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Dry versus liquid feeding in two contrasting finishing systems(fully slatted versus straw based housing)

Finishing Pigs: Systems ResearchProduction Trial 1

CONTENTS

EXECUTIVE SUMMARY

INTRODUCTION

OBJECTIVES

OUTLINE OF RESEARCH METHODOLOGY

Trial design

Diets and feeding

Animals and their management

Animals

Pig identification and weighing

Management

Research measurements

KEY RESULTS

Production

Feeding and housing

Variability

Feeds

Pig health and welfare

Losses and health conditions

Health monitoring

Behaviour

Slaughter assessments

Microbial status

Feed, water and straw

Faeces, effluent and dust

Pigs

Environmental impact

Ammonia and dust

Waste

Meat quality

Fresh meat, chemical composition and sensory quality

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TABLES Page

Table 1 Pig performance and carcase quality by housing and feeding system 11

Table 2 Pig performance and carcase quality by feeding within housing system 12

Table 3 Formulation against actual use of raw feed ingredients in the production of grower and finisher

liquid diets 13

Table 4 Nutrient analysis (%) of complete liquid and dry diets 13

Table 5 Major end products of natural fermentation in liquid diets 13

Table 6 Pig losses by housing and feeding system 14

Table 7 Pig losses by feeding within housing system 14

Table 8 Veterinary treatment (pig days) by housing and feeding system 15

Table 9 Veterinary treatment (pig days) by feeding within housing system 15

Table 10 Hygiene and skin lesion scores by feeding within housing system 15

Table 11 Acute Phase Proteins in blood by feeding within housing system 16

Table 12 Percentage time spent performing general activities by feeding within housing system 16

Table 13 Percentage time spent performing manipulative behaviours by feeding within housing system 16

Table 14 Slaughter assessments by feeding within housing system 17

Table 15 Microbial status of the feed, drinking water and fresh straw 17

Table 16 Microbial status of pen faeces, slurry and dust by housing and feeding system 18

Table 17 Detection of Salmonella in faecal, effluent and dust samples by housing, week and room 18

Table 18 Microbial status of pigs at slaughter by housing and feeding system 19

Table 19 Ammonia and dust emission and dust concentration 20

Table 20 Production and composition of waste 20

Table 21 Meat quality by housing and feeding system 21

APPENDICES 22

I OTHER RESULTS 24

II DETAILED RESEARCH METHODOLOGY 31

III SYSTEMS TECHNICAL SPECIFICATIONS 48

GLOSSARY 54

REFERENCES 57

ACKNOWLEDGEMENTS 59

EXECUTIVE SUMMARY

This report is based on the results from the first of four major production trials under the Finishing Systems Research Programme.

The research is evaluating two contrasting systems of housing (fully slatted v straw based) and liquid feeding technologies for pig

performance, carcase quality, cost of production, pig health and welfare, microbial status, environmental impact and meat quality.

PRODUCTION TRIAL 1

Dry and liquid (ad libitum) feeding were evaluated within a fully slatted and a straw based housing system using a total of 1024 pigs

housed in pen groups of 32 with a mean weight of 34kg (SD 4.0kg) at entry. Numbers per pen were reduced at week 6 to 25 in the

fully slatted and 20 in the straw based system and pigs were finished to slaughter at around 104kg.

The key findings according to the main effects of feeding, housing and systems interaction between feeding and housing are presented

below.

Feeding

Production

Liquid feeding significantly improved daily gain (796 v 754 g/day). Feed intake was significantly reduced in liquid fed pigs (1.75 v 1.85

kg/day).With liquid feeding, the combined effects of an improved daily gain and reduced intake resulted in a significant improvement

in feed conversion ratio (2.27 v 2.53).

Backfat thickness (P2) was similar in liquid and dry fed pigs (11.45 v 11.39 mm) at an average dead weight of 77kg.

There were no significant differences in the variability of gain and carcases quality (P2) between liquid and dry fed pigs.

Liquid feeding reduced cost of production by 4.6p/kg dead weight.


Overall mortality was low (1.2% in liquid and 0.6% in dry fed pigs).The number of pigs failing to complete the study for health reasons

did not differ significantly between feeding systems (4.8% in liquid and 6.2% in dry fed pigs), but significantly more pigs were removed

from the dry fed groups for respiratory conditions.Veterinary treatment for health was higher in liquid fed pigs (352 v 223 pig days),

with respiratory conditions and lameness being the major reasons for treatment. This included a greater level of management

intervention to curtail biting requiring increased use of BITEX for tail spraying and antibiotic treatment for tail injury in liquid fed

pigs.

Liquid fed pigs had a significantly lower hygiene score (i.e. were dirtier) than dry fed pigs (71% v 82% clean skin). Liquid feeding gave

rise to significant behavioural differences: liquid fed pigs were less active (59% v 52% of time spent ‘sleeping’) and spent less time

performing investigatory behaviours, particularly towards other pigs (7.5% v 9.4%) and pen parts (6.3% v 9.1%).

Post-slaughter assessment of foot damage showed no overall difference between liquid and dry fed pigs. Liquid fed pigs had

significantly less gastric ulceration than dry fed pigs (1.3 v 3.0 on a 0-5 severity scale).There were no significant differences in the

lung scores of liquid and dry fed pigs (1.5 v 1.2 on a 0-55 severity scale).

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Microbial status

Fermentation became established in the liquid feed by the presence of naturally occurring microbes as indicated by the significant

increase in viable aerobic and anaerobic, lactic acid bacteria and yeast counts. End product analysis indicated a lactic acid bacteria

dominated fermentation (1.3% lactic acid, 0.2% acetic acid and 0.3% ethanol).

Conversely, liquid feeding significantly decreased the microbial loading of the gut as shown by reductions in viable aerobic and

anaerobic, lactic acid bacteria, coliform and yeast counts at slaughter.

The lactic acid bacteria to coliform ratio in the gut and faeces was favourably and significantly increased by liquid feeding (1.48 v

1.31).

Salmonella could not be detected in samples of compounded dry diets, individual ingredients used in the production of liquid diets,

the final liquid feed mixtures or fresh straw. Pigs were the mostly likely route for Salmonella entry as around 8% tested positive

(ELISA) and one pig tested positive for caecal presence at entry.

Liquid feeding significantly reduced the percentage of pigs which tested positive for Salmonella at slaughter (ELISA 16 v 35%;

Caecal presence 23 v 39%).


There were no significant effects of dry or liquid feeding on dust and ammonia emissions or waste composition.

Liquid feeding significantly increased effluent production (7.31 v 5.20 litres per pig/day).

Meat quality

There were no differences of commercial importance in fresh and sensory meat quality of liquid and dry fed pigs.

Housing

Conclusive differences between the effects of housing systems will be established following the completion of the four production

studies. Interim key results from the first study are summarised below, but these should be treated with caution.

Production

There were no consistent effects of housing on growth performance and carcase quality.

The cost of production was 4.3p/kg dead weight higher in the straw based system.


Number of pigs removed for health conditions was higher from the fully slatted system (34 v 13), with lameness and tail injury

being the major reasons for removal.

Tail biting was also found in the straw based system with one pig removed for tail injury compared with 14 from the fully slatted

system.

Veterinary treatment for health was higher in the straw based system (359 v 216 pig days), with respiratory conditions being the

major reasons for treatment. Pigs housed in the fully slatted system required a greater level of management intervention to curtail

biting, with increased use of BITEX for tail spraying. Antibiotic treatment for tail injury was also higher in the fully slatted system.

Pigs in the fully slatted system had a significantly better hygiene score (85% v 68% clean skin).

Pigs in the straw based system were significantly more active than those in the fully slatted system, spending less time lying down

(67% v 74%) and less time ‘sleeping’ (51% v 61%).

Pigs in the straw based system spent a significant amount of their time investigating and manipulating straw (14.2%), whereas pigs

in the slatted system spent only 1.3% of their time investigating and manipulating the hanging ‘toy’ that was provided for them. Pigs

in the straw based system spent less time investigating pen components (6.7% v 8.8%), although a similar amount of time was

spent investigating other pigs in both systems (8.4% v 8.3%).

Post-slaughter assessment of the feet found no overall difference in the amount of damage; however there were significant

differences in the type of damage (on a 0-3 scale of severity). Pigs in the straw based system had significantly higher scores for

white line lesions (1.2 v 0.9) and toe erosions (1.2 v 0.5). Pigs in fully slatted system had more severe heel erosions (1.2 v 0.3).

Gastric ulceration (on a 0-5 scale of severity) was higher in pigs from the fully slatted system (2.5 v 1.9). There were no

significant effects of housing system on rind-side damage or lung score.

Microbial status

No major differences were found between the housing systems, with the exception of a significant increase in the microbial

loading (total aerobic viable and coliform counts) of dust sampled from the straw based system.

A higher percentage of pigs from the straw based system tested positive for Salmonella at slaughter (ELISA and caecal presence)

but the difference was not statistically significant.


No major differences were found between the housing systems.

Meat quality

No significant differences were found between the housing systems.

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Feeding and housing interactions

Production

Growth and feed conversion benefits from liquid feeding were significantly higher in the straw based system during the finishing

stage.

Liquid feeding reduced cost of production by 1.6p/kg dead weight in the fully slatted system and 7.6p/kg dead weight in the straw

based system.


The number of pigs removed for health conditions was higher with liquid feeding in the fully slatted system and with dry feeding in

the straw based system.

Whilst liquid feeding increased veterinary treatment for health conditions in both housing systems, the pattern of health

conditions requiring treatment differed according to feeding and housing system. Liquid feeding with fully slatted housing

increased veterinary treatment for lameness and tail biting/injury, whereas liquid feeding with straw based housing increased

treatment for respiratory and enteric conditions.

Liquid feeding reduced the hygiene score of the pigs in straw based housing to a much greater extent than in slatted housing.

However, there were no significant interactions between feeding and housing systems in respect of behavioural measures or post

mortem health assessments.

Microbial status

There were no consistent or major interactions between feeding and housing systems.


There were no significant feeding and housing interactions.

Meat quality

Sensory evaluations showed that cooked lean samples from liquid fed pigs housed in the straw based system had significantly

increased boar flavour scores, though this increase is unlikely to be of importance at the consumer level.There were no other

consistent or significant feeding and housing interactions.

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INTRODUCTION

The Finishing Systems Research Programme addresses Industry strategic and Government policy requirements covering several

priorities through a multidisciplinary approach.

Research activity is centred at MLC’s Stotfold Pig Development Unit using the purpose built Finishing Systems Research Unit.This

consists of a Feed Centre, which manufactures, processes and delivers liquid feed to growing/finishing pigs in two contrasting

systems of production, fully slatted v straw based housing.

The two housing systems will be evaluated over four production trials, with each trial designed to investigate liquid feeding

technology.

This report is based on the results of the first production trial, which compared dry and liquid feeding and provides the detailed

background information to the reporting of the subsequent trials.

OBJECTIVES

The objective of the research programme is to investigate the effect of housing and feeding and the interaction between housing

and feeding on:

Pig performance and cost of production


Microbial status


Meat quality

OUTLINE OF RESEARCH METHODOLOGY

Trial design

Dry and liquid feeding were evaluated in two contrasting systems of housing (straw- based v fully slatted) using growing and

finishing pigs from 34kg to slaughter at 104kg live weight.

Each house consisted of four rooms, with four pens within each room. Dry and liquid feeding treatments were replicated within

housing system and between rooms according to the following pattern.

Figure 1 Allocation of feeding treatments (dry v liquid) according to housing system and rooma

a Allocation of feeding treatment by room was necessary for the determination of the effects of feeding treatment (liquid v dry) on environmental

impact (see pages 20, 40, 41 and 47 for detail).

Room 1 2 3 4

Straw based Liquid Dry Liquid Dry

Room 1 2 3 4

Fully slatted Dry Liquid Dry Liquid

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Diets and feeding

The dry and liquid diets were formulated to the same nutrient specification using similar ingredients (see page 32 for

formulations). In Trial 1, no liquid co-products were used in the production of liquid diets.

There were two diets for both dry and liquid fed pigs, a grower diet fed from entry to about 60 kg (14.7 MJ DE/kg, 1.2% total

lysine) and a finisher diet from 60 kg to slaughter (14.2 MJ DE/kg, 0.9% total lysine).

The dry diets were manufactured commercially in 3mm pellets.The liquid diets were produced on site by milling cereals and

mixing individual ingredients using the liquid feeding system.

The dry diets were offered in ad libitum hoppers. Liquid feeding was computer controlled by feed demand at the troughs using

sensors, which signalled for refill on empty.Troughs were refilled with 15kg drops. Liquid feed was available ad libitum except

during the period between 24:00 and 01:00 hours when the system was automatically paused, allowing pigs to clear troughs of any

accumulated residues.

Animals and their management

Animals

A total of 1024 (Large White x Landrace) x Large White pigs weighing between 30 to 40kg were received in 8 equal batches of

132 over 11 weeks and transferred to the housing according to the following pattern.

Figure 2 Batch entry order during stocking according to housing system and room


Two pigs were randomly identified for slaughter for the baseline assessment of health and gut microbial status and two surplus

pigs were randomly selected and removed to alternative accommodation.The remaining 128 pigs were ear tagged for individual

identification and sorted by weight from lightest to heaviest.The batch was divided into 4 equal groups of 32 pigs in order of

weight: Light Light (LL), Light Medium (LM), Medium Heavy (MH) and Heavy Heavy (HH). Each group was randomly allocated to

one of four pens in the room.

On week 6 pigs were weighed and numbers were reduced from 32 to 25 and 20 pigs per pen in the fully slatted and straw based

systems respectively. Pigs removed were pre-selected to represent the range (minimum and maximum) and average weight in the

pen so that the overall distribution of individual weights was not skewed by random selection.

Pigs were weighed 9 days prior to slaughter and those weighing more than 95 kg were selected for slaughter so that the target

weight at slaughter could be close to 105kg. Pigs were re-weighed the day before slaughter.

Room 1 2 3 4

Straw based Batch 7 Batch 5 Batch 3 Batch 1

Room 1 2 3 4

Fully slatted Batch 8 Batch 6 Batch 4 Batch 2

Management

The management and care of the pigs is detailed in Appendix II and in brief covered the following elements:

Biosecurity to minimise the cross transfer of micro-organisms potentially associated with a particular feeding and housing system.

Management of the environmental control system to achieve target temperature and ventilation rates. Provision of toys for the

environmental enrichment of pigs in the fully slatted housing. Daily inspection to safeguard health and welfare, and under

Veterinary supervision to take appropriate action in the care and treatment of pigs with health conditions. Daily removal of soiled

bedding and provision of fresh straw in the straw based building. Daily inspection of drinkers and feeders to ensure correct

operation and absence of faecal contamination. Maintaining a high level of hygiene and tidiness in the feed centre and service areas.

Research measurements

To establish the potential effects of feeding (dry v liquid) and housing (straw based v fully slatted) on pig performance, pig health

and welfare, microbial ecology, environmental impact and meat quality the following measurements and records were taken.

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Pig production Pig weights, feed intake (automatically for liquid, manually for dry), nutrient analysis of feed

ingredients and complete diets, mortality and other losses, slaughter weight, commercial carcase

classification measurements (weight and P2), labour use (pig husbandry and cleaning), medicine

use, power consumption (liquid feed production and delivery, housing heating, lighting and

ventilation and cleaning), water use (liquid feed, drinking and cleaning), straw use, effluent and

manure production and cost of production.

Pig health and

behaviour

All pigs: any individual health or welfare condition, pen faecal consistency, veterinary treatments,

reasons for death (post mortem) or pigs removed from study.

Focal pigs (6 per pen): skin lesions and cleanliness, hock bursitis, behavioural time budgets, feeding

behaviour.At slaughter: skin damage, foot lesions, osteochondrosis, heart and lung scores, gastric

ulceration. Blood samples at entry, mid-point and slaughter evaluated for acute phase proteins,

generalised immunity and PRRS virus.

Microbial status Salmonella:All pigs at entry and slaughter blood sampled for ELISA test, plus all pigs at slaughter

tested for the presence of Salmonella in caecal samples. Individual feed ingredients, complete

diets, straw, dust, pen faeces and effluent routinely tested for the presence of Salmonella.Where

appropriate, microbial evaluations of systems samples also included total aerobic and anaerobic

viable counts, lactic acid bacteria, enterobacteraciae, coliform and yeast counts and Lawsonia and

Brachyspira.

Environmental impact In the straw and fully slatted housing by room: ammonia and dust concentrations and emissions.

Effluent and farm yard manure production and composition.

Meat quality Fat firmness, subcutaneous fat skatole and indole contents, and fatty acid profile, drip loss, muscle

colour, simulated retail display, oxidative rancidity (TBARS) and sensory evaluation of cooked

loins.

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KEY RESULTS

Production

Feeding and housing

Pig performance and carcase quality according to housing and feeding system are given in Table 1. Pig performance and carcase

quality according to feeding system (dry v liquid) within housing system are given in Table 2.

Table 1 Pig performance and carcase quality by housing and feeding system

Housing System Feeding System s.e.d.b Pa

Fully Straw Liquid Dry H F I

slatted based

Live weight (kg)

Entry 35.62 32.75 34.14 34.23 1.286 *

Mid 67.00 61.78 65.50 63.28 1.982 **

Final 102.60 103.20 103.00 102.90 0.753 **

Feed intake (kg/pig day)

Grower 1.51 1.39 1.44 1.47 0.040 ** **

Finisher 2.21 2.39 2.22 2.39 0.053 ** **

Overall 1.82 1.78 1.75 1.85 0.021 * *** *

Growth (g/day)

Grower 707 666 717 656 17.2 * ***

Finisher 832 852 853 831 16.0 **

Overall 781 768 796 754 9.6 *** **

Feed conversion ratio

Grower 2.15 2.10 2.00 2.24 0.062 *** *

Finisher 2.67 2.83 2.60 2.89 0.075 0.06 *** **

Overall 2.39 2.41 2.27 2.53 0.027 ***

Carcase quality

Slaughter weight (kg) 103.6 103.7 103.6 103.7 0.54 *

Carcase weight (kg) 77.09 76.89 76.60 77.38 0.415 0.07 *

Killing out % 74.40 74.18 73.96 74.62 0.207 **

Backfat P2 (mm) 11.75 11.08 11.45 11.39 0.304 *

Number (n) of observations per mean = 16.a In this and subsequent tables, significant probability (P) values for housing system (H), feeding system (F) and interaction (I) between housing

and feeding system are given as *, ** or *** for P values <0.05, <0.01 and <0.001 respectively. P values >0.05 and <0.1 are presented

numerically and P>0.1 are left blank.A P value of <0.05 (5% level) is taken as a statistically significant effect.b s.e.d. is the standard error of difference.

Table 2 Pig performance and carcase quality by feeding within housing system

Fully slatted Straw based s.e.d. P

Liquid Dry Liquid Dry H F I

Live weight (kg)

Entry 36.26 34.98 32.02 33.48 1.819 *

Mid 69.38 64.63 61.62 61.93 2.803 **

Final 101.60 103.60 104.30 102.20 1.065 **

Feed intake (kg/pig day)

Grower 1.44 1.59 1.44 1.35 0.057 ** **

Finisher 2.16 2.26 2.27 2.52 0.075 ** **

Overall 1.75 1.90 1.75 1.80 0.029 * *** *

Growth (g/day)

Grower 733 682 702 629 24.4 * ***

Finisher 815 849 891 813 22.6 **

Overall 785 777 807 730 13.6 *** **

Feed conversion ratio

Grower 1.96 2.33 2.05 2.15 0.088 *** *

Finisher 2.66 2.68 2.54 3.10 0.106 0.06 *** **

Overall 2.27 2.50 2.26 2.57 0.038 ***

Carcase quality

Slaughter weight (kg) 102.9 104.3 104.3 103.1 0.76 *

Carcase weight (kg) 76.18 78.00 77.01 76.76 0.587 0.07 *

Killing out % 74.04 74.77 73.89 74.48 0.293 **

Backfat P2 (mm) 11.70 11.81 11.19 10.97 0.430 *

Number of observations per mean = 8

Variability

There were no significant differences in the variability for intake, growth and carcase fatness according to feeding and housing

system.

Feeding and housing could influence the variability in the growth rate and carcase fatness of individual pigs. For example ad libitum

liquid feeding may generate greater competition for feed during automatic delivery and in turn this may result in a greater spread

of growth rate and subsequent fatness of pigs at slaughter.This was investigated by subjecting the within pen standard deviation (a

measure of variability) for daily gain and carcase P2 to statistical analysis. No significant effects of feeding or housing system were

found (see Appendix I Table 7).

Feeds

The target formulation against actual use of raw feed ingredients in the production of grower and finisher liquid diets are given in

Table 3.The results from the laboratory analysis of samples of complete liquid and dry diets are given in Table 4.

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Table 3 Formulation against actual use of raw feed ingredients in the production of grower and finisher

liquid diets

Grower diet Finisher diet

Formulation Actual Formulation Actual

Ingredient (%)

Wheat 41.30 40.78 38.62 36.93

Barley 13.77 12.09 12.87 11.01

Wheatfeed 10.00 10.02 20.00 20.36

Soya bean meal (HP) 18.37 19.50 10.05 13.52

Rapeseed meal 5.00 5.19 10.00 9.84

Fish meal 2.50 3.79 --- ---

Soya oil 5.96 5.65 5.36 5.29

Minerals and vitamins 3.10 3.00 3.10 3.05

Formulations adjusted according to sample analysis of newly delivered batches of major individual feed ingredients

(see Appendix II Table 1).

Table 4 Nutrient analysis (%) of complete liquid and dry diets

Liquid dietsa Dry diets

Grower (n=11) Finisher (n=16) Grower (n=8) Finisher (n=9)

Mean SDd Mean SD Mean SD Mean SD

Dry matterb 14.7 3.25 16.2 2.93 88.6 0.33 88.7 0.31

Crude protein 19.0 3.25 19.6 4.21 17.3 0.46 15.0 0.77

Oil (B) 10.0 1.50 8.8 1.19 7.0 0.38 6.2 0.56

NDAF 14.1 4.68 17.5 4.34 11.6 0.45 14.2 0.59

Ash 6.5 0.72 5.8 0.87 5.3 0.42 5.1 0.44

Total lysine 1.05 0.23 0.88 0.16 0.98 0.15 0.75 0.12

Calcium 0.70 0.106 0.61 0.077 - - - -

Phosphorus 0.69 0.058 0.65 0.079 - - - -

Copper (mg/kg) 180 26.2 112 27.5 - - - -

DE (MJ/kg)c 14.1 0.55 13.8 0.53 14.6 0.23 14.0 0.29a In liquid diets the nutrients were adjusted to a meal equivalent of 87% dry matter.b The target dry matter content of liquid diets was 20%, which was achieved according to the weight of ingredients and water used and recorded

automatically by the liquid feeding system. However, a representative sample of the final diet was difficult to obtain due to the rapid settling of

the particulate fraction when the stirrers were switched off for sampling.c Estimated by regression MAFF (1993).d Standard deviation.

Additional samples of liquid diets were taken on site and tested for dry matter content and pH.The dry matter content (see

note b under Table 4) and pH of the grower and finisher diets were very similar and averaged 17.7% (SD 1.87) and 4.9 (SD 0.21)

respectively.

Major end products of natural fermentation found in the liquid diets are given in Table 5.

Table 5 Major end products of natural fermentation in liquid diets

Mean (n = 6) SD

mg/kg mmol/litre % mg/kg mmol/litre %

Ethanol 3175 64 0.3 822 16 0.08

Lactic acid 13272 147 1.3 1485 17 0.15

Acetic acid 2328 38 0.2 660 11 0.07

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Losses and health conditions

Pig losses through deaths and health conditions by housing and feeding system are given in Table 6. The results are presented by

feeding system within each housing system in Table 7.Veterinary treatment for health conditions by housing and feeding system are

given in Table 8. The results are presented by feeding system within each housing system in Table 9.

Table 6 Pig losses by housing and feeding system

Housing system Feeding system

Fully slatted Straw based Liquid Dry

Losses (number)

Deaths

Grower 3 (0.59)a 6 (1.17) 6 (1.17) 3 (0.59)

Finisher 0 0 0 0

Removed

Grower 21 11 11 21

Finisher 13 2 9 6

Total 37 19 26 30

Health condition (number)

Respiratory 4 5 1 8

Enteric 1 2 1 2

Lameness/physical damage 11 3 10 4

Tail injury 14 1 6 9

Multipleb 1 3 2 2

Otherc 6 5 6 5

Total 37 19 26 30a Value in parenthesis is % mortality.b Individual pigs with multiple conditions (e.g. respiratory, enteric, post-weaning multi-systemic wasting syndrome or PMWS).c Includes prolapsed, abscess, sudden death, poor body condition and meningitis.

Table 7 Pig losses by feeding within housing system

Fully Slatted Straw Based

Liquid Dry Liquid Dry

Losses (number)

Deaths

Grower 2 (0.78) 1 (0.39) 4 (1.56) 2 (0.78)

Finisher 0 0 0 0

Removed

Grower 10 11 1 10

Finisher 9 4 0 2

Total 21 16 5 14

Health condition (number)

Respiratory 1 3 0 5

Enteric 1 0 0 2


Tail injury 6 8 0 1

Multiple 0 1 2 1

Other 4 2 2 3

Total 21 16 5 14

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Table 8 Veterinary treatment (pig days)a by housing and feeding system


Fully slatted Straw based Liquid Dry

Health condition

Respiratory 26 250 150 126

Enteric 0 49 40 9


Tail bitingb 83 1 50 34

Tail injuryc 28 0 23 5

Multiple 0 0 0 0

Other 8 14 11 11

Total 216 359 352 223a Each day a pig was treated for a given health condition, including consecutive and repeated treatments on the same pig.b In pens where an outbreak of tail biting was observed tails were sprayed with BITEX (topical application containing a bitter compound, 1%

bitrex) as a management intervention to curtail biting.c Pigs with tail injury due to biting and at risk of infection or with signs of infection were treated with veterinary prescribed antibiotics.

Table 9 Veterinary treatment (pig days) by feeding within housing system

Fully Slatted Straw Based


Health condition

Respiratory 5 21 145 105

Enteric 0 0 40 9


Tail biting 50 33 0 1

Tail injury 23 5 0 0

Multiple 0 0 0 0

Other 3 5 8 6

Total 140 76 212 147

Health monitoring

Weekly skin lesion and hygiene scores according to feeding within housing system are given in Table 10. Results from analysis of

blood samples for Acute Phase Proteins at different stages in the trial are shown in Table 11.

Table 10 Hygiene and skin lesion scores by feeding within housing system

Fully slatted Straw based P


Lesions/pig 14 11 13 16

Hygiene score (% clean) 82 87 60 76 *** *** **

Bursitis (0-5) 1.1 1.0 1.0 1.1

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Table 11 Acute Phase Proteins in blood by feeding within housing system



At entry

C-Reactive protein 129 148 137 129

Haptoglobin 0.73 0.75 0.62 0.56

At mid-point


Haptoglobin 1.64 1.23 0.81 1.09 ** *

At slaughter


Haptoglobin 0.67 0.71 0.39 0.48 **

Behaviour

Percentage time spent performing general activities by feeding within housing system is given in Table 12. Percentage time spent

performing manipulative behaviours by feeding within housing system is given in Table 13.

Table 12 Percentage time spent performing general activities by feeding within housing system



% Time

Lying 78 69 69 65 ** **

‘Sleeping’ 65 56 52 49 *** **

Eating 3.9 4.4 4.6 5.0

Drinking 0.4 1.2 0.7 1.2 ***

Table 13 Percentage time spent performing manipulative behaviours by feeding within housing system



% Time

Straw - - 14.0 14.3 ***

Toy 1.1 1.5 - - *** **

Other pig 7.0 10.0 7.9 8.8 **

Pen parts 6.9 10.6 5.7 7.6 * ***


A summary of all slaughter assessments by feeding within housing system is given in Table 14.

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Table 14 Slaughter assessments by feeding within housing system



Foot lesions ( 0-3 scale)

White line lesion 0.8 1.0 1.1 1.2 *

Toe erosion 0.5 0.4 1.2 1.1 ***

Sole erosion 0.7 0.9 0.7 0.8

Heel erosion 1.0 1.3 0.3 0.2 ***

Osteochondrosis (04 scale)

Front score 2.5 2.4 2.5 2.7

Rear score 2.0 2.0 2.0 1.9

Gastric ulceration (0-5 scale) 1.7 3.2 0.9 2.8 ** ***

Rind-side damage (0-5 scale) 2.2 2.3 2.3 2.2

Lung score (0-55 scale) 1.5 1.0 1.5 1.3

Microbial status

Feed, water and straw

All microbial analysis results, unless otherwise indicated, are presented as Log10 colony forming units (cfu) per gram or per ml as

appropriate.The microbial status of the compounded complete dry diets and individual feed ingredients used in the production of

the resulting liquid diets, and water and straw samples is given in Table 15.

Table 15 Microbial status of the feed, drinking water and fresh straw

n

Liquid feed ingredients

Wheat 1 ND 5.06 4.39 2.61 3.80 4.13

Barley 1 ND 6.64 6.34 4.53 6.27 2.74

Wheatfeed 2 ND 5.78 5.12 4.02 3.09 2.76

Soya bean meal (HP) 1 ND 4.38 3.31 3.70 2.47 3.16

Rapeseed meal 2 ND 6.23 5.91 5.13 3.33 4.76

Fish meal 1 ND 3.48 4.76 ND ND ND

Minerals and vitamins (Grower) 1 ND 1.48 2.60 ND ND ND

Minerals and vitamins (Finisher) 2 ND 3.36 2.95 1.18 ND ND

Complete liquid diets

Grower 12 ND 8.72b 8.63b 9.15b 2.19 6.80b

Finisher 12 ND 8.95b 8.83b 9.25b 2.41 7.17b

Complete dry diets

Grower 14 ND 5.13a 4.47a 3.17a 1.98 2.66a

Finisher 14 ND 4.78a 4.04a 3.12a 2.16 3.52a

Drinking water ND

Fresh straw ND

ND = not detecteda, b Mean bearing the same superscript letter within the same column are not statistically significant (P>0.05).

Faeces, effluent and dust

The microbial status of faecal, effluent and dust samples according to housing and feeding system is given in Table 16.The detection

of Salmonella in faecal, effluent and dust samples is presented by housing system, room, batch, pen and date in Table 17.

Sal

mo

nella

Tota

l Aer

obi

cV

iabl

e C

oun

t

Tota

l Ana

ero

bic

Via

ble

Co

unt

Lac

tic

acid

bact

eria

Co

unt

Ent

ero

bact

erac

iae

Co

unt

Co

lifo

rm C

oun

t

Yeas

t C

oun

t

18

Table 16 Microbial status of pen faeces, slurry and dust by housing and feeding system

Housing system Feeding system s.e.d. P

n Fully Straw Liquid Dry H F I

slatted based

Total Aerobic Viable Count

Faeces 12 8.73 8.66 8.65 8.74 0.139

Dust 38 6.91 7.92 7.41 7.44 0.137 ***

Total Anaerobic Viable Count

Faeces 12 8.95 8.98 8.87 9.06 0.118

Lactic Acid Bacteria (LAB) Count

Faeces 12 8.35 8.46 8.25 8.56 0.111 **

Coliform Count

Faeces 12 6.73 6.59 6.31 7.01 0.197 **

Dust 38 2.11 3.30 2.72 2.71 0.187 *** *

LAB : Coliform Ratio

Faeces 12 1.25 1.29 1.32 1.22 0.037 *

Enterobacteraciae Count

Effluent 12 5.48 5.47 5.51 0.292 - -

Table 17 Detection of Salmonella in faecal, effluent and dust samples by housing, week and room

Faeces Effluent Dust

Housing system Week of Room Pen number Room Log10 Room Log10

study tested positive cfu/ml cfu/g

Fully slatted 6 3 21, 23 3 35 3 2

9 3 4

11 3 23 3 14

12 3 5

13 3,1 5, 160 2 2

15 3 23 3,2,1 160,22,35

16 2 4

18 1 4 1 4

Straw based 10 1 3,4 3 <2

12 2 5,7

14 1,3 1,3,9,10,11,12 1,2 2,<2

16 2 8

Pigs

The microbial status of the pigs at entry, according to housing and feeding systems allocation, is given in Appendix I Table 8.With

the exception of Salmonella ELISA showing a significantly higher percentage positive for pigs entering the fully slatted compared

with the straw based system (10% v 5%, P<0.01), overall the microbial status was broadly similar according to systems allocation.

This shows that there was no initial treatment bias for the microbial status of pigs at the start of the trial.The presence of

Brachyspira and Lawsonia in the caecal contents of pigs slaughtered at entry are given in Appendix I,Table 9.The microbial status

of pigs at slaughter is given in Table 18.

19

Table 18 Microbial status of pigs at slaughter by housing and feeding system



slatted based

Salmonella 16

Caecal %positive 28 34 23 39 7.5 *

ELISA %positive 22 29 16 35 7.3 *

Total Aerobic Viable Count

96

Ileal 8.29 8.32 8.04 8.58 0.283 **

Caecal 8.12 8.21 7.78 8.56 0.217 **

Colon 8.52 8.51 8.09 8.94 0.230 **

Total Anaerobic Viable Count

96

Ileal 8.57 8.65 8.38 8.84 0.266 ***

Caecal 8.97 9.14 8.81 9.30 0.250 **

Colon 9.12 9.24 8.89 9.48 0.213 **

Lactic Acid Bacteria (LAB) Count

96

Ileal 8.07 8.20 7.94 8.33 0.284 **

Caecal 8.19 8.30 7.85 8.65 0.243 ** *

Colon 8.74 8.81 8.39 9.16 0.224 **

Coliform Count 96

Ileal 8.07 7.80 7.55 8.33 0.409 **

Caecal 6.31 6.54 5.84 7.02 0.304 **

Colon 6.44 6.44 5.79 7.10 0.275 **

LAB : Coliform Ratio 96

Ileal 1.01 1.06 1.07 1.01 0.027 0.064 *

Caecal 1.32 1.31 1.37 1.26 0.029 **

Colon 1.38 1.41 1.48 1.31 0.033 **

Yeast Count 96

Ileal 5.06 4.85 4.56 5.36 0.318 **

Caecal 4.32 4.03 4.03 4.32 0.314 0.074 0.07 ***

Colon 4.04 3.83 3.91 3.97 0.252 0.094 0.09

20


Ammonia and dust

Ammonia and dust emission and dust concentration according to housing and feeding system are presented in Table 19.

Table 19 Ammonia and dust emission and dust concentration

Fully slatted Straw based


Ammonia

Emission (g NH3-N per lu hour) 1.90 1.64 2.02 1.94

Dust

Concentration (mg per m3) 1.83 3.17 1.81 2.02

Emission (g per lu hour) 0.85 1.80 1.09 1.21

There were no significant differences between different housing and feeding systems (n=4).

Waste

The volume of effluent and weight of farm yard manure generated and composition is presented in Table 20. Liquid compared with

dry feeding significantly (P<0.001; s.e.d. 0.367) increased the volume of effluent produced in the fully slatted system.

Table 20 Production and compositiona of waste



Production (pig/day)

Effluent (litres) 7.31 5.20 - -

Farm Yard Manure (kg) - - 3.40

Compositiona (n=7)

Dry matter (%) 6.90 6.45 17.2

Ammoniacal nitrogen

(mg NH4-N/kg) 3105 3033 2385

Kjeldahl nitrogen (mg N/kg) 4355 4076 5561

Total phosphorous (mg/kg) 837 1238 1551a Composition results highly influenced by sampling error and not statistically significant.

Meat quality

Fresh meat, chemical composition and sensory quality

The results from the evaluation of fresh meat samples for quality and chemical composition and sensory panel scoring of cooked

samples are presented in Table 21.There were no consistent significant interactions between feeding and housing system.

The subcutaneous fat characteristics and sample fatty acid profiles by housing and feed system are presented in Appendix I Table 10.

21

Table 21 Meat quality by housing and feeding system



slatted based

Fresh 64

Drip loss (%) 6.75 5.36 5.79 6.31 0.932

Colour Saturation

Day 3 7.43 7.16 7.65 6.94 0.179 ***

Retail cutting 7.28 7.05 7.50 6.83 0.219 **

Display day 1 9.00 8.37 8.90 8.46 0.217 ** *

Display day 2 8.69 8.30 8.69 8.29 0.192 * *

Display day 3 8.56 7.96 8.46 8.07 0.213 **

TBARS 20

Display day 1 0.024 0.030 0.030 0.024 0.003

Display day 3 0.069 0.083 0.085 0.067 0.008 *

Taints (ppm) 20

Indole 0.030 0.032 0.034 0.028 0.006

Skatole 0.044 0.062 0.056 0.049 0.015

Cooking loss (%) 23.17 22.66 22.93 22.89 0.664

Eating 64

Lean

Juiciness 14.58 14.94 15.01 14.51 0.446

Tenderness 15.50 16.03 15.76 15.77 0.449

Pork flavour 13.12 13.36 13.34 13.14 0.378

Abnormal flavour 3.03 2.89 2.73 3.19 0.321

Boar flavoura 1.88 1.98 2.10 1.76 0.173 0.051 **

Overall Acceptability 13.43 13.77 13.63 13.57 0.442

Fat

Pork flavour 11.63 11.74 11.98 11.39 0.397

Abnormal flavour 1.88 2.04 1.93 2.00 0.206

Boar flavour 1.41 1.45 1.46 1.40 0.105

Pork odour 10.12 10.21 10.22 10.11 0.401

Abnormal odour 2.95 2.93 2.81 3.07 0.309

Androstenone odour 1.60 1.72 1.64 1.68 0.173

Skatole odour 1.45 1.35 1.42 1.38 0.124a The H x F significant interaction (P<0.01) for boar flavour in the lean was due to a higher mean score (2.40) given to samples from pigs housed

in the straw based system fed liquid feed.

22

APPENDICES Page

APPENDIX I OTHER RESULTS 24

Tables

Table 1 Inputs and waste production 24

Table 2 Input costs 25

Table 3 Cost of production (p/kg dead weight) by housing and feeding system 26

Table 4 Cost of production (p/kg dead weight) by feeding within housing system 26

Table 5 Sensitivity analysis for cost of production (p/kg dead weight) by feeding within housing system 27

Table 6 Nutrient analysis of liquid feed ingredients 28

Table 7 Variability (SD) in gain and carcase quality by housing and feeding system 28

Table 8 Microbial status of pigs at entry by housing and feeding system 29

Table 9 Brachyspira and Lawsonia presence in caecal contents at entry 30

Table 10 Subcutaneous fat characteristics and fatty acid profile of the lean 30

APPENDIX II DETAILED RESEARCH METHODOLOGY 31

Pig production 31

Housing 31

Feed centre 31

Feeding 32

Feed sampling and laboratory analysis 33

Animals 34

Pig identification and weighing 35

Management 35

Straw and water use and power consumption 36

Waste production 36

Pig health and welfare 36

Blood sampling 37

Health monitoring 37

Skin lesions and cleanliness 37

Behavioural recording 37

Slaughter assessments 38

Microbial status 38

Sampling 38

Microbial evaluations 39

Environmental impact 40

Ventilation rate 41

Ammonia 41

Dust 41

Waste 41

Meat quality 42

Carcase measurements and sampling 42

Chemical analysis 44

Simulated retail display 44

Sensory evaluation 44

23

Page

Data processing 46

Production 46


Microbial status 46

Meat quality 46

Statistical analysis 47

Production 47


Microbial status 47

Environmental impact 47

Meat quality 47

Tables

Table 1 Meal equivalent formulations and nutrient specifications of diets 32

Table 2 Feed and feed ingredients sampled and their laboratory analysis 34

Table 3 Blood sampling and analysis for health and Salmonella status 37

Table 4 Summary of microbial evaluations of samples 39

Table 5 Media and conditions for microbial counts performed on samples 40

Table 6 Summary of environmental monitoring 40

Table 7 Selection of focal pigs for carcase and meat quality evaluations 43

Table 8 Sensory evaluation of cooked loin chops 45

APPENDIX III SYSTEMS TECHNICAL SPECIFICATIONS 48

Finishing system 48

Buildings 48

Ventilation system 48

Liquid feeding trough 51

Feed centre 52

Tables

Table 1 Settings for the environmental control system in the finishing buildings 48

24

APPENDIX I OTHER RESULTSTable 1 Inputs and waste production

Fully slatted Straw basedLiquid Dry Liquid Dry

Feed (kg)Grower (Per pig) 64.9 69.1 60.7 61.2Finisher (Per pig) 85.7 104.4 108.4 124.8

Labour (minutes)Husbandry

Per pig day 0.14 0.14 0.40 0.40Per pig 11.8 12.6 36.0 37.8

CleaningPer pig day 0.06 0.06 0.05 0.05

Per pig 5.3 5.3 4.6 4.7Medicines

Per pig day (p) 0.34 0.12 0.89 0.63Per pig (p) 28.60 10.44 80.05 59.60

Power consumption (kWh)Buildings


Liquid feed production and deliveryPer pig day 1.15 - 1.15 -

Per pig 95.89 - 103.19 -Power washing


Water used (litres)a

Drinking and liquid feedPer pig day 7.69 5.91 6.72 4.46

Per pig 640.46 522.20 602.20 419.85Cleaning


Straw used (kg)Per pig day - - 0.49 0.49

Per pig - - 44.23 46.49MortalityGrowing stage (34 to 64kg)

(%) 0.78 0.39 1.56 0.78Mean weight (kg) 32.00 58.5 38.63 38

Finishing stage (64 to 103kg)(%) 0 0 0 0

Pigs removedGrowing stage (34 to 64kg)

(%) 3.91 4.30 0.39 3.91Mean weight (kg) 47.65 45 35.00 39.05

Finishing stage (64 to 103kg)(%) 4.50 2.00 0.00 1.25

Mean weight (kg) 79.22 80.88 0.00 87.75Waste production (kg)Farm Yard Manure

Per pig day - - 3.40 3.40Per pig - - 304.26 319.78

EffluentPer pig day 7.31 5.20 - -

Per pig 608.06 460.57 - -a Meters used to monitor drinking and cleaning water overestimated actual use by around 25%.Values given in Table 1 above are based

on previous research (Gill, 1988).

25

Table 2 Input costs

Unit Cost per unit (£) Notes

Variable Inputs

Weaner pig 32.50 Weaner costs were loaded for systems mortality. Pigs

removed during the growing stage for health conditions

were added to mortality losses.

Feed Based on September 2003 costs.

Barley t 85

Wheatfeed t 75

Wheat t 92

Rapeseed Meal t 108

Soya bean meal t 160

Fish meal t 480

Soya oil t 380

Grower mins/vits supplement t 345

Finisher mins/vits supplement t 280

Grower compound t 167 Includes £25/t margin plus £7/t delivery over baseline

raw feed costs

Finisher compound t 149 As above

Labour hr 7.15 Average of basic rate plus 10hrs o/t per week, including

National Insurance etc.

Power kWh 0.04 Assuming 50/50 normal and cheap rate tariff.

Water m3 0.70

Straw t 30 Wheat straw

Waste management

Farm Yard Manure t Contractor disposal cost of £2.40 per m3

Effluent t Contractor disposal cost of £1.72 per m3

Capital Investment Total Capital cost of feeding equipment (dry and liquid)

depreciated over 20 years at 6% interest. Capital cost of

straw and fully slatted housing depreciated over 30 and

25 years at 6% interest. Repair/maintenance costs at 2%

for housing and 4% for feeding equipment.

Liquid feeding

Mill 8,500 1t/hr 3-phase hammer mill + elevator - including

installation

Central processing unit 42,300 Bins and augers for 3 cereals, 2 proteins and oil, with

processing tank and controls, installed in new building.

Pig house tank/pipeline 13,620 Tank, pipeline and 16 feeders.

Dry feeding

Bin/Auger/feeders 5,300 Feed bin, centreless auger and 16 feeders.

Housing

Fully slatted m3 227 Average of trade quotes based on building plan.

Straw based m3 193 As above.

26

Table 3 Cost of productiona (p/kg dead weight) by housing and feeding system


Fully Straw Liquid Dry

slatted based

Variable costs

Feed 33.7 34.6 28.9 39.5

Vet and Med 0.3 1.0 0.8 0.5

Bedding 0 2.1 1.0 1.0

Total 34.0 37.6 30.7 41.0

Fixed costs

Housing 5.6 4.9 5.1 5.4

Feed system 1.4 1.5 2.3 0.6

Labour 3.0 6.9 4.7 5.1

Energy 4.8 4.2 6.9 2.0

Water 0.7 0.4 0.6 0.5

Slurry storage and disposal 2.0 1.1 1.6 1.4

Total 17.5 18.8 21.2 14.9

Total Finishing Cost 51.5 56.4 51.9 55.9

Weaner cost 43.3 42.7 42.7 43.3

TOTAL COST 94.8 99.1 94.6 99.2a Totals are correct individual costs subject to rounding to one decimal place.

Table 4 Cost of production (p/kg dead weight) by feeding within housing system



Variable costs

Feed 29.0 38.4 28.7 40.5

Vet and Med 0.4 0.2 1.1 0.8

Bedding 0.0 0.0 2.1 2.0

Total 29.4 38.6 31.8 43.4

Fixed costs

Housing 5.5 5.6 4.6 5.1

Feed system 2.2 0.5 2.4 0.6

Labour 3.0 3.0 6.5 7.2

Energy 7.4 2.2 6.5 1.8

Water 0.8 0.6 0.4 0.4

Slurry storage and disposal 2.3 1.7 1.0 1.1

Total 21.2 13.6 21.4 16.2

Total Finishing Costs 50.6 52.2 53.2 59.6

Weaner cost 43.3 43.3 42.1 43.3

TOTAL COST 93.9 95.5 95.3 102.9

27

Table 5 Sensitivity analysis for cost of production (p/kg dead weight) by feeding within housing system



Base line cost of productiona 93.9 95.5 95.3 102.9

Cost of liquid feeding system (+/- of baseline)

+10% 94.1 - 95.5 -

-10% 93.7 - 95.0 -

Feed costs (+/- of base line)

+10% 96.8 98.6 98.1 106.1

-10% 91.0 92.4 92.4 99.7

No difference in growth rate and FCR between dry and liquid fed pigs (see data)

97.3 95.5 102.0 102.9

Installation sizeb

Below IPPC threshold

1000 pig places 94.5 - 95.9 -

At IPPC threshold

2000 pig places 93.9 95.5 95.3 102.9

Above IPPC threshold

4000 pig places 93.5 - 94.7 -a From Table 4.b Estimated to determine the effects of unit size on the spread of overhead costs associated with capital investment in a liquid feeding system.

28

Table 6 Nutrient analysis of liquid feed ingredients

Nutrients (% dry matter) n DM CP Oil (B) NDAF Ash DE (MJ/kg)a Total lysine Ca P Na

Feed ingredient

Whole grain wheat 2 86.80 12.45 2.30 11.30 1.50 14.53

Wheatfeed pellets 2 85.30 15.55 4.45 31.15 4.00 11.70

Whole grain barley 1 86.80 10.30 2.90 15.90 5.60 12.73

Rapeseed meal 2 88.55 33.00 4.85 28.80 6.75 12.90

Soya bean meal (HP) 1 88.30 49.10 1.90 8.30 6.10 16.31

Fish meal 1 90.80 60.30 10.60 8.50 22.10 13.99

Grower mineral and

vitamins premix 2 2.93 22.25 4.78 9.97

Finisher mineral and

vitamins premix 3 2.47 23.49 2.50 11.04a Estimated by regression MAFF (1993).

Table 7 Variability (SD) in gain and carcase quality by housing and feeding system



slatted based

Growth (g/day)

Grower 16 165 178 184 159 17.5

Finisher 16 152 137 153 136 16.0

Overall 16 91 85 97 80 8.7 0.06

Carcase quality

Slaughter weight (kg) 16 4.40 5.01 5.06 4.34 0.492

Carcase weight (kg) 16 3.73 3.97 3.91 3.79 0.375

Killing out % 16 2.42 2.13 2.23 2.32 0.179

Backfat P2 (mm) 16 2.24 1.97 2.19 2.02 0.151 0.08

29

Table 8 Microbial status of pigs at entry by housing and feeding system



slatted based

Salmonella

Caecal %positive 16 See note (a) below - - - -

ELISA %positive 16 10 5 6 9 1.60 ** *

Total Aerobic Viable Count 8

Ileal 8.06 8.44 8.58 7.93 0.310 0.059 *

Caecal 8.45 8.44 8.65 8.23 0.200 0.058

Colon 8.69 8.68 8.72 8.65 0.220

Total Anaerobic Viable Count 8

Ileal 8.39 9.04 9.04 8.40 0.628 0.061 0.064

Caecal 8.95 9.30 9.13 9.13 0.263

Colon 9.19 9.20 9.23 9.15 0.173

Lactic Acid Bacteria (LAB) 8

Ileal 7.77 8.48 8.32 7.93 0.442

Caecal 8.38 8.61 8.59 8.40 0.293

Colon 8.80 8.76 8.83 8.72 0.223

Coliform count 8

Ileal 6.82 6.81 7.12 6.51 0.571

Caecal 7.54 7.15 7.42 7.27 0.376

Colon 7.48 7.12 7.40 7.16 0.488

LAB : Coliform Ratio 8

Ileal 1.15 1.30 1.18 1.26 0.132

Caecal 1.12 1.21 1.16 1.17 0.063

Colon 1.20 1.24 1.20 1.24 0.069

Yeast count 8

Ileal 4.59 4.78 4.70 4.67 0.652

Caecal 4.87 4.36 4.70 4.53 0.500

Colon 4.46 4.06 4.34 4.14 0.578

Note: (a) One pig was found positive for Salmonella presence.

Table 9 Brachyspira and Lawsonia presence in caecal contents at entry

Date Animal no. B. hyodysenteriae B. innocens B. pilosicoli Lawsonia

22 Apr 02

7 May 02

13 May 02

27 May 02

5 Jun 02

17 Jun 02

24 Jun 02

1 Jul 02

Table 10 Subcutaneous fat characteristics and fatty acid profile of the lean



slatted based

Fat characteristics

Backfat P2 (mm) 16 11.75 11.08 11.45 11.39 *

Fat Firmness (subjective) 64 4.50 4.52 4.14 4.87 0.169 ***

Mean penetrometer score 64 706.4 698.3 677.3 727.4 18.6 **

g fatty acids/100g lean 20 1.28 1.04 1.22 1.10 0.096 *

g/100g fatty acids 20

Saturated 32.91 31.49 31.41 33.00 0.613 * *

Monounsaturated 30.22 28.32 29.78 28.76 1.276

Polyunsaturated 32.46 35.34 34.31 33.49 1.497

Aldehydes 1.47 1.70 1.36 1.80 0.131 **

Total 97.06 96.85 96.87 97.04 0.124

30

19

39

64

73

178

196

229

231

283

316

269

296

443

391

401

485

-

-

+

+

-

-

-

-

+

-

+

+

+

-

-

-

+

+

+

+

-

-

-

-

+

-

+

+

+

+

+

-

+

-

-

-

+

-

-

-

+

-

-

+

-

-

-

-

+

-

-

-

-

-

-

-

-

-

-

-

+

-

-

-

31

APPENDIX II DETAILED RESEARCH METHODOLOGY

Pig production

Housing

The Finishing Systems Research Unit (FSRU) located at MLC’s Stotfold Pig Development Unit consists of a Feed Centre, which

manufactures and delivers liquid feed to growing/finishing pigs in two contrasting systems of production, fully slatted v straw based

housing.

Each house consists of four rooms and each room contains four pens. Both houses have a reception area with pig weighing

facilities, ventilation controllers and storage for clothing and other equipment.The drawings for the two housing systems and pen

layouts are further details can be found in Appendix III.

Feed centre

The feed centre houses a dry feed storage and milling unit and a state-of-the-art liquid processing and feeding system (see

Appendix III for further detail).

The dry feed storage holds six ingredients in cloth silos, whole grain wheat and barley, pelleted wheatfeed, soyabean meal and

rapeseed meal.Wheat, barley and wheatfeed are hammer milled into small cloth bins (fitted with load cells) before transfer by

auger to the central processing tank of the liquid feeding system.The dry feed storage houses 3 small rip and tip bins for mineral

and vitamin supplements and fishmeal.These bins also deliver material to the central processing tank by independent augers.

Feed centre

Fully-slatted house

Straw-based house

Liquid co-product storage tanks

32

The liquid feeding system was supplied by Meyer Lohne (Germany), and designed in association with MLC to meet the

requirements of the research programme. It consists of 6 tanks fitted with load cells, with a central processing tank as the focal

point for the intake, proportioning and blending of all individual ingredients (dry and up to 4 liquid co-products, plus soya oil) to

any formulation specified in the computer controlled Winfeed programme.The central processing tank can heat materials to 95°C

and then chill before transfer to one of 5 different tanks. Depending on protocol, the blend can be transferred into one of two

fermentation tanks, as in the case of a cereal mix, or into a protein tank as in the case of a protein rich blend.These can then be

transferred independently to one of two feeding tanks linked to the dual pipeline system delivering feed to the two pig finishing

buildings.All tanks have the facility for micro additions of dry and liquid products, such as enzymes and organic acids and the

processing and fermentation tanks are equipped with pH control systems.

The dual pipeline arrangement can phase-feed to deliver different proportions of the two mixes held in the feeding tanks

according to the nutritional requirements of each pen group of pigs.

Feeding

Pigs were fed a growing and a finishing diet either in dry pelleted or in liquid form.The liquid and dry diets were formulated to

similar nutrient specification and using similar feed ingredients (see Table 1).

Table 1 Meal equivalent formulations and nutrient specifications of diets

Grower diets Finisher diets


Ingredient (%)

Wheat 41.30 38.25 38.62 35.15

Barley 13.77 12.65 12.87 11.75

Wheatfeed 10.00 10.00 20.00 20.00

Soya bean meal (HP) 18.37 2.00 10.05 ---

Fullfat soya --- 21.50 --- 12.50

Rapeseed meal 5.00 5.00 10.00 10.00

Fish meal 2.50 2.50 --- ---

Fat blend --- --- --- 2.50

Soya oil 5.96 2.00 5.36 2.00

Molasses --- 3.00 --- 3.00

Minerals and vitaminsa 3.10 3.10 3.10 3.10

Nutrient Specificationb

DE (MJ/kg) 14.75 14.72 14.13 14.22

Lysine (%) 1.22 1.17 0.94 0.89

Ca (%) 0.79 0.90 0.73 0.83

P (%) 0.68 0.67 0.59 0.56

Na (%) 0.40 0.42 0.40 0.40a Mineral and vitamin supplement provided per kg of grower diet:Vitamins A, D and E 9000, 1500 and 75 iu respectively,Vitamin K 1000 ug,

Riboflavin 5 mg, Pyridoxine 6 mg, Cyanocobalamin 45 mg, Biotin 100 ug, Pantothenic acid 24 mg, Niacin 23 mg, Copper 175 mg, Zinc 85 mg,

Manganese 35 mg, Iron 40 mg, Iodine 1.75 mg and Selenium 0.4 mg. Mineral and vitamin supplement provided per kg of finisher diet:Vitamins A,

D and E 6000, 1500 and 70 iu respectively,Vitamin K 1000 ug, Riboflavin 2 mg, Pyridoxine 4 mg, Cyanocobalamin 30 mg, Biotin 66 ug, Pantothenic

acid 16 mg, Niacin 15 mg,Thiamine 0.5 mg, Copper 100 mg, Zinc 80 mg, Manganese 25 mg, Iron 100 mg, Iodine 0.5 mg, Cobalt 0.5 mg and

Selenium 0.45 mg.The supplements also provided per kg of grower diet: 1.74 g lysine as lysine hydrochloride, 9.10 g salt, 6.04 g Calcium and

1.53 g Phosphorous; and per kg of finisher diet 1.27 g lysine as lysine hydrochloride, 9.75 g salt, 6.67 g Calcium and 0.69 g Phosphorous.b Differences in expected nutrient specifications between dry and liquid formulations are due to differences in MLC and Farm Nutrition matrix

values for individual ingredients.

33

Dry feed was manufactured (Farm Nutrition, Provimi Ltd) in 3mm pellets and delivered in 25kg bags.The feed was manually

weighed and tipped into ad libitum hoppers. Feed was offered ad libitum.To estimate intake and feed conversion ratios (feed

intake/body weight gain), residual feed was weighed when pigs were weighed and deducted from feed inputs.

The liquid feed was manufactured on site in the Feed Centre (see Appendix III) according to formulations given in Table 1. The

formulations were adjusted according to sample analysis of newly delivered batches of major individual feed ingredients.Water was

pre-weighed into the Central Processing Tank (Tank 3) to produce liquid feed (grower or finisher) in batches of around 370kg with

a 20% target dry matter content.

Whole grain wheat and barley and wheatfeed pellets were hammer milled (4.5 mm screen) and transferred with other feed

ingredients to the Central Processing Tank.

The components were mixed and transferred to Tanks 5 and 6 (grower) and 4 (finisher) for temporary storage at ambient

temperature before delivery in complete batches to feeding Tanks 1 (A) and 2 (B) respectively.This process was led by feed

demand at the troughs using sensors, which signalled for refill on empty.Troughs were refilled with 15kg drops of either grower or

finisher feed according to growth stage of each pen group (when mean weight of pigs in pen exceeded 60kg, they were

transferred from the grower to the finisher diet). Liquid feed was available ad libitum except during 24:00 and 01:00 when the

system was automatically paused, allowing pigs to clear troughs of any accumulated residues.

Feed sampling and laboratory analysis

Each newly delivered batch of individual feed ingredient and compounded dry pelleted feed was sampled and dispatched (Sciantec

Analytical Services Ltd., North Yorkshire, England) for nutrient analysis.The results from the analysis of feed ingredients were used

to adjust formulations in the production of liquid diets to meet target DE and total lysine content.

Grower and finisher liquid diets were sampled during the course of the trial from Feed Tanks A and B for on site determination of

oven dry matter content (24hrs at 100oC), and pH (Hanna Instruments HI 991000).Weekly liquid diet samples were stored for

subsequent dispatch and laboratory analysis for nutrient content (Sciantec Analytical Services Ltd., North Yorkshire, England).

A summary of samples taken and associated laboratory analysis are given in Table 2.

34

Cru

de p

rote

in (

CP

)

Oil

(B)

Neu

tral

det

erge

nt

plus

amyl

ase

fibre

(N

DA

F)

Ash

Tota

l lys

ine

Cal

cium

(C

a) a

nd

pho

spho

rous

(P

)

So

dium

(N

a)

Co

pper

(C

u)

Fatt

y an

d vo

lati

le a

cid

pro

files

,eth

ano

l and

pH

Room 1 2 3 4

Batch 7 Batch 5 Batch 3 Batch 1

Straw basedPen 2 Pen 4 Pen 6 Pen 8 Pen 10 Pen 12 Pen 14 Pen 16

Pen 1 Pen 3 Pen 5 Pen 7 Pen 9 Pen 11 Pen 13 Pen 15

Room 1 2 3 4

Batch 8 Batch 6 Batch 4 Batch 2

Fully SlattedPen 31 Pen 29 Pen 27 Pen 25 Pen 23 Pen 21 Pen 19 Pen 17

Pen 32 Pen 30 Pen 28 Pen 26 Pen 24 Pen 22 Pen 20 Pen 18

Table 2 Feed and feed ingredients sampled and their laboratory analysis

Feed ingredient

Whole grain wheat � � � � �

Wheatfeed pellets � � � � �

Whole grain barley � � � � �

Rapeseed meal � � � � �

Soya bean meal (HP) � � � � �

Fish meal � � � � �

Grower mineral and vitamins premix � � �

Finisher mineral and vitamins premix � � �

Complete liquid diet � � � � � � � � �

Complete dry pelleted diet � � � � � �

DM, Oil (B),Ash, Ca, P, Na and Cu were determined according to the methods described by MAFF (1982). CP was determined by

nitrogen gas analyzer (Leco FP – 528) using induction furnace and thermal conductivity. NDAF was determined according to the

method described by MAFF (1993).Total lysine content in feed samples was analysed according to Liu et al. (1995).The

component fatty acid content of the lipid fraction were determined according to ISO (1995) and ISO (2001).Volatile fatty acid

content, lactic acid and ethanol in liquid feed samples were analysed according to Fussel and McCalley (1987). pH was measured

using a pH probe (Hanna Instruments HI 991000).

Animals

A total of 1056 (Large White x Landrace) x Large White pigs weighing between 30 to 40kg were received in 8 equal batches of

132 over 11 weeks commencing 12th April 2002. Pigs were delivered on a Friday and transferred to a room in the finishing

systems housing according to the pattern given below.

Dry

mat

ter

(DM

)

35


On the following Monday, two pigs were randomly identified for slaughter for the baseline assessment of gut microbial status and

two surplus pigs were randomly selected and removed to alternative accommodation.The remaining 128 pigs were ear tagged for

individual identification, weighed and then sorted by weight, from lightest to heaviest.The batch was divided into 4 equal groups of

32 pigs in order of weight: Light Light (LL), Light Medium (LM), Medium Heavy (MH) and Heavy Heavy (HH). Each group was

randomly allocated to one of four pens in the room.

Pigs were weighed at two weekly intervals for growth performance monitoring and to establish the timing (week 6) at which pen

weight within room averaged 60kg for stocking density reduction and the switch from grower to finisher diet. On week 6 pigs

were weighed and stocking density in the fully slatted and straw based systems was reduced from 32 to 25 and 20 pigs per pen

respectively. Pigs removed were pre-selected to represent the range (minimum and maximum) and average weight in the pen so

that the overall distribution of individual weights was not potentially skewed by random selection.

Pigs were weighed 9 days prior to slaughter and those weighing more than 95 kg were selected for slaughter so that weight at

slaughter could be as close as possible to a target of 105kg. Pigs were weighed again the day before slaughter for determination of

end point liveweight.

Pigs selected for slaughter were slap marked for individual identification and this was recorded on the slaughter sheets with

corresponding information for pen number, pig ear tag number, sex, dispatch weight and pre-selection code for focal pigs (see

Health and Welfare Monitoring). Slap marking clearly distinguished focal pigs from other trial pigs.

Management

Pigs were managed according to standard protocol covering the following key responsibilities:

The day before entry the environmental control system was set up to achieve target temperature and ventilation rates (see

Appendix III:Ventilation system).

Staff changed overalls and wellington boots before entering each building. Foot dips (Virudine,Antec International Ltd., Suffolk)

were used on entry and exit. Separate foot dips were used for each building and these were cleaned and replenished twice per

week.

Pigs in the slatted building were provided with chains and plastic mats were used in the first two weeks in the fully slatted house

to reduce draughts in the lying area.

Pigs were inspected twice daily for signs of ill health and welfare.Appropriate action was taken to manage pigs with health

conditions. Health conditions were recorded and appropriate action was taken to safe guard the welfare of each pig.Treatments

were carried out according to veterinary recommendations and all veterinary treatments were documented. Pigs that did not

respond to veterinary treatment and where welfare was at risk, were weighed and removed from the study and recorded with

date.

All deaths and culls for health conditions were recorded and a post-mortem was conducted by a Veterinary Surgeon to assess the

cause of death.

36

In each room, the ventilation system was checked and temperature readings were taken and recorded using a hand held probe

during the morning inspection of animals every Monday,Wednesday and Friday. Readings were taken at pig level in the middle of

each of 4 pens in each room.

Soiled bedding was removed daily from each pen.The straw based system was scraped out daily (farm scraper was cleaned and

disinfected (Virkon S,Antec International Ltd., Suffolk) before use to limit microbial cross contamination) and fresh straw was

made available at the rate of about a third of a bale per pen per day.

All nipple drinkers were inspected daily to ensure satisfactory water flow. Feed troughs and probe sensors were inspected twice

daily, any contaminated feed, faeces and straw were removed. Central passages were cleaned daily.

Straw and water use and power consumption

Straw use was monitored by recording the number of bales used daily and a sub-sample of bales were weighed during the trial as

an estimate of total weight used.

Drinking water used within each room and water used for cleaning each finishing building was measured using 12.5 mm water

meters (Minomess,Apartment Water Meters, Minol Messtechnik, Germany).

Power consumption in the Feed Centre for the milling, material transfer, mixing, circulation and delivery of liquid feeds to troughs

was measured using electric meters (RDL Power Rail 303). Power consumption for heating and ventilation of each finishing

building was measured using electric meters (RDL 3P100ANL Power Meters).

Waste production

In the fully slatted house, the volume of effluent produced by each pen group of pigs was measured by dipstick at four locations

within the pen area. Measurements were taken before and after emptying to estimate difference in surface fall (h). Slurry pit width

(w), length (l) and h were used to calculate the volume of effluent produced by each pen group as w x l x h.

Manure production from the straw based system was weighed daily by scraping waste onto a trailer fitted with weight cells.The

weight of manure produced was estimated by taking load cell readings before and after loading with waste. It was not practical to

estimate waste production at the pen level due to the use of common scraping passages either side of the central passage (see

Appendix III, buildings).


Standard management procedures for monitoring and safeguarding the health and welfare of pigs on trial were complemented by

more detailed observations on sub-samples of pigs (focal pigs).

Following entry and allocation of pigs within batch to pens, 3 pairs (balanced by weight and sex) were selected as focal pigs; one

pair at approximately median weight of the group, one pair within the upper quartile weight band and another pair in the lower

quartile weight band. Focal pigs remained in the pen after stocking density reduction at around 60kg for subsequent monitoring to

finishing and at slaughter.Any focal pig removed or lost from the trial (health, welfare or death) was replaced with a pig of the

same sex and approximate start weight.

37

Blood sampling

Pigs were blood sampled under veterinary supervision (Home office Licence number PPL 70/5367) for the determination of health

and Salmonella exposure status at entry, at mid-point in the trial (at stocking density reduction) and during exsanguination at

slaughter.The number of pigs sampled and analysis is summarised in Table 3 below.

Table 3 Blood sampling and analysis for health and Salmonella status

Analysis Pigs

Salmonella ELISA test All pigs at entry (8 batches x 128 pigs per batch, n = 1024)

Focal pigs at mid-point, batches 1 to 4 (4 batches x 24 pigs per batch, n = 96)

All pigs at slaughter (n = 720)

Acute Phase Proteins All focal pigs at start (8 batches x 24 pigs per batch, n = 192)

Focal pigs at mid-point, batches 1 to 4 (4 batches x 24 pigs per batch, n = 96)

All focal pigs at slaughter ( 8 batches x 24 pigs per batch, n= 192)

Generalised immunity Focal pigs at start, mid-point and slaughter, batches 1 to 4 (n = 288)

PRRS virus Focal pigs (15 from 24 per batch), batches 1 and 8 only, start, mid-point and slaughter (n = 90)

Health monitoring

All pigs, including focals were subjected to weekly detailed health monitoring.This included records of any incidence of external

clinical signs of respiratory, locomotory and enteric disorders, behavioural vices such as tail, flank or ear lesions and any other

problems (e.g. hernias, abscesses and rectal prolapse).

The average faecal consistency was scored weekly for each pen on a subjective visual scale of 1 to 5 (1 very loose to 5 very solid).

Skin lesions and cleanliness

Hygiene status of focal pigs was scored weekly by visual estimation of the % whole body surface area which was clean (as

opposed to soiled).

Body lesions were counted weekly on each of the focal pigs. Seven areas of the body were assessed: face and ears, neck, shoulders,

flank, rump, buttocks and tail. For each area (excluding the tail), lesions on the left and right hand sides were recorded separately.

Bursitis of the hock in focal pigs was visually scored weekly on a subjective scale of 0 to 5 according to Lyons et al. (1995) as

follows: 0 no bursitis, 1 small raised swelling, 2 moderate swelling, 3 fairly extensive swelling, 4 very severe swelling and 5

eroded/ulcerated bursa with infection.

Behavioural recording

Behavioural time budgets for focal pigs were recorded concurrently by time sampling at 10 minute intervals for three 2-hour

periods (09.00-11.00, 12.00-14.00, and 15.00-17.00hrs).This was repeated 3 times for each room: in the week of entry, the week

prior to stocking density reduction and the week before slaughter. Data were entered onto a standard recording sheet using an

ethogram.

A 24-hour video record of behaviour at the feed trough was taken in each of the 3 weeks detailed above. Focal pigs within each

pen were uniquely spray marked so that they could be recognised individually.

The number of pigs feeding and queuing for the trough was recorded at 5 minute intervals.The feeding bouts of focal pigs were

individually documented. For each bout, the start and end time and method of initiation and termination were recorded.

38


Foot damage of focal pigs was subjectively evaluated on the slaughter line based on the method described by Lyons et al. (1995).

Both claws of the left hind foot were inspected for the presence of white line lesions, false sandcracks, toe erosions, sole erosions,

and heel flaps (torn heels).These conditions were scored on a scale of 0 to 3, with 0 no damage and 3 as severe damage.

The hearts and lungs of all pigs were removed and scored for lesions by a Veterinary Surgeon.All seven lung lobes were scored: 4

were scored out of 10, and 3 scored out of 5 to give a maximum total score of 55 for any given pig (Goodwin and Whittlestone,

1979). Lesions on the lobes were scored proportionately; if lesion covered 20% of the surface area of a lobe it was scored as 2. If

other conditions were present (for example pleurisy, scarring), they were scored on an increasing severity scale (+,++ or +++).

The heart was inspected for evidence of pericarditis and scored on an increasing severity scale (+,++ or +++).

The gastrointestinal tract of focal pigs was scored for gastric ulceration (including hyperkeratosis of the gastric pars oesophagus)

according to Potkins and Lawrence ( 1989). Any digesta was removed from the pars oesophagus and its surface condition was

subjectively scored on a scale of 0 to 5: 0 apparently normal, 1 hyperkeratosis just beginning, 2 slight hyperkeratosis, 3 moderate

hyperkeratosis, 4 severe hyperkeratosis and 5 severe hyperkeratosis and ulcer (active or healed).

The dressed carcases of focal pigs were scored for skin damage using the standard MLC subjective scale of 1 to 5: 1 unblemished

to 5 severely blemished.

The leg joints of 2 pairs (equal sexes) of focal pigs per pen were dissected to expose the joint.The extent of osteochondrosis was

scored according to Slevin et al. (2001) on a scale of 0 normal (no gross lesion) to 4 generalised dulling, deep depressions and

extensive erosion, ulceration or absence of cartilage.

Microbial status

Gut contents on entry and at slaughter, individual feed ingredients, complete diets (dry and liquid), fresh straw, drinking water,

fresh faeces, effluent and dust were sampled during the trial for microbial evaluations by the Veterinary Laboratories Agency (VLA,

Bury St Edmunds). Sterilised equipment and sample containers were used to avoid cross contamination. Blood samples were taken

from all pigs on entry and during exsanguination at slaughter, plus additional samples were taken from focal pigs at mid-point for

Salmonella ELISA testing as described by Heijden (2001).

Sampling

Gut contents (ileum, caecum and colon) were sampled from 2 randomly selected pigs per batch on entry (Tuesday) and from all

focal pigs at slaughter. Caecal contents were sampled from all pigs at slaughter. Ligated segments of the ileum, caecum and colon

were removed and placed in an insulated box with cool packs. Segments were transported to the VLA for sampling.

All feed ingredients (except soya oil) were sampled during delivery to Stotfold Pig Development Unit. Pelleted dry compound

diets were sampled from unopened bags from each new batch of delivered feed.Weekly samples of dry pelleted diets from

unopened bags and liquid diets (grower and finisher mix) from the feed tanks (Tanks 1 and 2, see Appendix III) were taken.

Bales used for bedding the straw based system were sampled on 9 separate occasions during the course of the trial.

Each room was fitted with a water tap from which samples were taken on 3 separate occasions (on stocking with pigs, mid-point

and on emptying).Taps were flushed and cleaned using 70% alcohol prior to sampling.

Pens were sampled for fresh faeces on 3 separate occasions (on stocking with pigs, mid-point and on emptying). Each pen was

sampled from 4 locations and these sub-samples were pooled for analysis. Samples were taken from the dunging area and slatted

flooring of the straw based fully slatted systems.

39

Sal

mo

nella

Tota

l Aer

obi

c V

iabl

e C

oun

t

Tota

l Ana

ero

bic

Via

ble

Co

unt

Lac

tic

acid

bac

teri

a

Ent

ero

bact

erac

iae

coun

t

Co

lifo

rm c

oun

t

Yeas

t co

unt

Law

soni

a an

d B

rach

yspi

ra

Effluent samples were taken weekly from each room within the fully slatted system.The pit under each pen was sampled from 4

locations and pen sub-samples were pooled to represent the room sample for analysis.

Dust samples were taken weekly from each room. Samples were taken from the windowsills along the outer walls of the room

using a sterile Petri dish exposed for 2 hours.

Microbial evaluations

The samples were evaluated for the following microbial organisms.

Table 4 Summary of microbial evaluations of samples

Gut contents at entry (8 pigs)

Ileum � � � � �

Caecum � � � � � �

Colon � � � � � �

Gut contents at slaughter

Ileum (focal pigs only) � � � � �

Caecum (focal pigs only) � � � � �

Colon (focal pigs only) � � � � �

Caecum (all pigs) �

Feed ingredients � � � � � �

Complete feeds � � � � � �

Fresh straw �

Drinking water �

Fresh faeces � � � � �

Effluent � �

Dust � � �

40

Table 5 Media and conditions for microbial counts performed on samples

Microbial organism Media and inoculation Supplement Incubation Reference

Salmonella Buffered peptone, 37°C for 18h;

Diassalm semi-solid agar, 30°C/41.5°C Netten et al. (1991)

Rambach agar, for 24/48h;

Columbia agar, 37°C for 24h

MacConkey agar serial incubations

Total aerobic bacteria Plate count agar, 5% defibrinated sheep Aerobic, for 72 h ISO (1991)

viable count pour plate blood for gut samples

only

Total anaerobic Wilkins-Chalgren 5% defibrinated sheep Anaerobic, 37°C

bacteria viable count Anaerobe agar, blood for 48 h

spread plate

Lactic acid bacteria MRS agar, spread 5% CO2, 30°C

plate for 48 h

Enterobacteraciae Violet red bile Aerobic, 37°C Mackie and

count glucose agar, pour for 24 h MacCartney (1965)

plate

Coliform count VRBL agar, Aerobic, 37°C

MacConkey broth for 18 to 24 h

Yeast Rose Bengal agar Chloramphenico Aerobic, 25°C

l, Oxoid SR78 for 4 days

Lawsonia and PCR Jones et al. (1993),

Brachyspira Moller et al. (1998) and

Leser et al. (1997)

Limits of detection; for pour plates, 10 cfu per g: for spread plates, 100 per g.


The table below summarises systems monitoring for the assessment of environmental impact of housing and feeding system

during Production Trials 1, 2 and 4.

Table 6 Summary of environmental monitoring

Parameter monitored Frequencya

Ammonia concentration at the entry to the exhaust Once per hour per room, continuously

fan in each room

Dust concentration at one position in each room 14 occasions, each nominally of 3 days duration, nominally once aweek

Ventilation rate of each room Hourly averages, computed from a large number of basic readings

Ammonia emission rate from each room One value per hour per room, continuously

Dust emission rate from each room 14 occasions, each nominally of 3 days duration, nominally once a week

Effluent volume from each slatted room Each occasion of emptying slurry pit

Effluent composition from each slatted room Each occasion of emptying slurry pit

Farm Yard Manure production from whole straw Each occasion of cleaning out the straw based building

based building

FYM composition from whole straw based building Analysis carried out on a pooled sample, once every 14 daysa In trials 2 and 4 dust concentration will be measured at a reduced frequency of once per fortnight during the period when both buildings are

fully stocked.

41

Ventilation rate

Ventilation rate was continuously measured for each room using a fan-wheel anemometer installed in the exhaust duct, between

the inlet damper and the exhaust fan (Demmers et al., 1999). The rate of rotation of the fan wheel as well as the opening angle of

the inlet damper were continuously monitored electronically, to give an accurate log of the instantaneous ventilation rate of each

room. Each fan-wheel anemometer was calibrated by installation in an identical ventilation chimney fitted to a fan test rig at Silsoe

Research Institute before the start of Trial 1 (Moulsley and Randall, 1990).This calibration will be checked at the end of trial 4.Any

variation in the calibration curve and hence ventilation rate will be accounted for after trial 4.

Ammonia

Ammonia concentration was measured using a chemiluminescence-type nitric oxide analyzer (Demmers et al., 1999), following

catalytic conversion of ammonia to nitric oxide at 750˚C. Measurements were taken at 12 locations, at entry to the exhaust fan

within each room of the straw based and fully slatted housing and at four placed immediately outside the buildings, to correct for

ambient ammonia entering the buildings.The analyzer was calibrated regularly using certified standard gas mixtures.

Net ammonia emission rate for each room was estimated as a function of hourly ammonia concentration and hourly ventilation

rate, corrected for any incoming concentration of ammonia.The ammonia emission was normalised to the live weight of pigs in

each room.The ammonia emission factor (g NH3-N per live weight unit per hour) was calculated from the cumulative emission.

One live weight unit corresponds to 500 kg live weight.

Dust

Dust concentration was measured at entry to the exhaust fan within each room of the straw based and fully slatted housing

(Takai et al., 1998). Dust concentration was also measured at one of the air inlets in the sidewalls of one room to correct for dust

entering the buildings.

The average ventilation rate over the period of exposure of each set of dust concentration samplers (normally 3 days) was

multiplied by the average dust concentration (corrected for any incoming dust), to give average dust emission rate for each room.

Waste

The volume and weight of waste (effluent and manure) produced were monitored as described on page 36.

Slurry samples were taken immediately before pit emptying for the determination of dry matter, total nitrogen and ammoniacal

nitrogen and phosphorous content according to APHA (1985).Analysis was carried out on a pooled sample representing the

content of the slurry pits within each room.

Four grab samples of manure were taken from the trailer, at randomly selected points, at 14 day intervals for the determination of

dry matter, total nitrogen, ammoniacal nitrogen and phosphorous content.The samples were combined, coned and quartered to

give a 1 kg sample for analysis.

42

Meat quality

Carcase measurements and sampling

Pigs were transported to the abattoir and slaughtered (day 1) under commercial conditions and the carcases were conditioned

using achilles suspension.

The carcases were graded using the Hennessy Grading Probe for the estimation of carcase lean content using the following EU

approved (88/234/EEC) equation:

Y = 62.5 – 0.62X1 – 0.46X3 + 0.16X4

where,

Y = the estimated percentage of lean meat in the carcase,

X1 = the thickness of backfat (including rind) in mm, measured at 6 cm off the midline of the carcase at the last rib (commonly

known as P2),

X3 = the thickness of backfat (including rind) in mm, measured at 6 cm off the midline of the carcase between the 3rd and 4th

last ribs (known as ‘rib-fat’),

X4 = the thickness of muscle in mm, measured at the same time and in the same place as X3 (known as ‘rib-muscle’).

Carcases were chilled overnight under commercial slaughter house conditions (1°C).The left side of the carcase from 4 out of 6

focal pigs (see selection Table 7) were transported (day 2) to MLC Winterhill House, Milton Keynes, under controlled refrigeration

and stored in a chiller at 1°C for subsequent evaluation.

On day 3, firmness measurements were taken of the subcutaneous fat by penetrometer over the shoulder and leg. Subjective fat

firmness scores, on scale of 1 to 8 (1= very soft (oily), 8 = very hard), over the shoulder and leg were assessed by depressing the

subcutaneous fat with the tip of a finger or thumb.

The sides will were butchered to provide the following samples:

Shoulder fat (200g); vacuum packed and frozen for subsequent analysis of skatole and indole levels.

Shoulder fat (100g); vacuum packed and frozen for subsequent analysis for fatty acid profile.

Single steak (20 mm); from the anterior end of the loin for immediate assessment of drip loss according to the following method.

The steak was weighed and suspended in a polythene bag for 24 hours at 1°C.The steak was removed from the bag and

reweighed.The drip was weighed.The eye-muscle was removed from the steak and weighed. Per cent drip loss was calculated as

(weight of drip loss/(weight of drip + weight of eye-muscle))*100.

43

Table 7 Selection of focal pigs for carcase and meat quality evaluations

Housing system Room Pen Meat quality evaluationsa Chemical analysisb

Fully slatted 1 32 2 mixed sex pairs 1 male and 1 female

31 2 mixed sex pairs 1 female

30 2 mixed sex pairs 1 male


2 28 2 mixed sex pairs 1 female


26 2 mixed sex pairs 1 female and 1 male


3 24 2 mixed sex pairs 1 male







17 2 mixed sex pairs 1 male and 1 female

Straw based 1 1 2 mixed sex pairs 1 male and 1 female








3 9 2 mixed sex pairs 1 male







16 2 mixed sex pairs 1 male and 1 female

Total 64 pairs = 128 20 males and 20 females = 40a Evaluations include: fat firmness, drip loss, Minolta Chroma Meter readings, simulated retail display and sensory evaluations.b Analysis includes: skatole, indole, fatty acid profile and TBARS.

44

Remainder of the boneless primal loin was vacuum packed and held in refrigerated storage (0-3ºC) until Day 8.

Minolta Chroma Meter readings were taken on the cut surface of each loin, at the anterior end, following a period of blooming

and prior to vacuum packing.

On Day 8 the primal loin was butchered to provide the following samples (from the anterior end):

Three over-wrapped retail packs, each of two steaks (20 mm) for simulated retail display.

Two steaks (20 mm) vacuum packed and frozen for subsequent sensory evaluation.

Chemical analysis

Skatole and indole were determined according to the method described by Whittington et al. (1995). Fatty acid profiles were

determined by direct saponification according to Enser et al. (1998).

Simulated retail display

The three retail packs per side were placed in a chiller for a period of simulated retail display (at 0-3ºC). The packs were opened

in sequence at 1, 3, 4, 5 and 7 days. On opening, Minolta Chroma Meter readings were taken and the steaks vacuum packed and

frozen. Following the end of the trial, day 1 and day 7 samples were frozen for subsequent TBARS (thiobarbituric acid values)

assessment according to Vyncke (1970).

Sensory evaluation

Trained sensory panellists were used to evaluate lean and fat samples from cooked loin steaks for the attributes presented in

Table 8.

Panel sessions were structured so that samples from each housing system x feeding treatment were compared in each session.

Six samples were allocated to each session in an incomplete block design so that there were male and female pigs represented in

each session. (Not all treatments were represented in both sexes).This resulted in a total of 22 single panel sessions for the trial.

In each session all samples were assessed by six experienced sensory panellists. Cooking and sampling procedures are

documented below.

Vacuum packed steaks (2 per carcase) were selected from the freezer and thawed for 24 hours in a chiller at 3°C.

Steaks were removed from the packs about an hour before cooking and where necessary trimmed to a uniform thickness of 20

mm and weighed. Steaks were placed on a cooking turntable.The grill (Stot Benham Supergrill 600 gas grill) was set at the highest

temperature and the turntable was placed under the burners.

45

Table 8 Sensory evaluation of cooked loin chops

Sample Attribute Method

Lean

Juiciness Tasting

Tenderness

Pork flavour

Abnormal flavour

Boar flavour

Fat

Pork flavour

Abnormal flavour

Boar flavour

Lean and fat

Overall acceptability

Fat

Pork odour Smelling

Abnormal odour

Androstenone

Skatole

Steaks were grilled to an internal temperature of 75°C (monitored at the end of cooking using a Comark probe C9003

thermometer,Welwyn Garden City, Herts), about 5 minutes on each side. During cooking, the turntable was rotated

approximately 60 degrees every 25 seconds.After cooking, the steaks were removed and placed on coded plates and each steak

was re-weighed on a clean plate (one plate per steak to avoid transfer of flavour components between samples) to establish

cooking loss. Each steak was loosely wrapped in aluminium foil, returned to its coded plate and held in a hot cabinet (54°C) until

sub-sampling for sensory evaluation.

Steaks were removed from the cabinet, one at a time, and placed on a clean chopping board.The fat was separated from the lean.

Six cubes, one per trained sensory panellist, about 1.5 to 2.0 cms in size, were cut from the lean, discarding the outside edges. Six

unbrowned fat samples, about 1 cm were also cut. One sample of lean and another of fat was wrapped in aluminium foil. Excess

fat from each pair of chops was placed in a coded, screw-top, wide-mouth glass jar for odour assessment.The wrapped samples,

one from each allocation within sensory session, were placed in individual wells of a circular microwave bun-tray and returned to

the hot cabinet until all samples were ready for sensory evaluation.

The bun-trays were transferred to the sensory booths within the panelling room. Each booth was illuminated by a green light (to

eliminate bias from sample colour differences) and was equipped with a hot plate onto which a bun-tray was placed. Panellists

were provided within each booth with a small white plate, knife, fork, glass of warm water and a piece of white toast (to cleanse

residual flavour between sampling) and a disposable cup for residues.The jars containing fat samples, were placed on a hot plate,

for assessment by all panellists.

The six trained sensory panellists were asked to score wrapped lean and fat samples and fat samples within jars, on a psuedo line

24 point scale (1 = weak/low to 24 = strong/high) for the attributes listed in Table 8. For statistical analysis, individual panellist

scores were averaged to give a single score per attribute per pig sampled.

46

Data processing

Production

Feed intake (kg/pig day) was derived from total intake per pen divided by total pig days per pen specific to the grower and finisher

stages and overall (grower plus finisher stages).

Growth rate (g/pig day) was derived from total net weight gain per pen divided by total pig days per pen specific to the grower

and finisher stages.The overall growth rate was calculated for only those pigs left in the pens for finishing after the numbers were

reduced at the end of the grower stage (week 6).

Feed conversion (intake/gain), was derived from total intake per pen divided by net weight gain per pen specific to the grower and

finisher stages and overall (grower plus finisher stages).

All other inputs (labour, medicine, power, water and straw) and farm yard manure production were calculated overall (combined

grower and finisher stages) from total input (or manure produced) per housing system divided by total pig days specific to each

feeding system. Effluent production was measured for each pen and total output was divided by total pigs days for each pen over

the combined grower and finisher stages.


Health, hygiene and lesion scores were averaged across pigs within each pen, and across recording weeks for each pen. Behaviour

data were expressed as the proportion of observations at which that behaviour was expressed. These data were

subsequently averaged across pigs within each pen, and across recording weeks for each pen. All of the post-slaughter

assessments were averaged across pigs within each pen.

Microbial status

All microbial counts were transformed to log10 before analysis.

Salmonella tests on blood (ELISA) and caecal contents (laboratory incubation) were recorded as either positive or negative and

present or absent respectively.These data were used to calculate the proportion of pigs that tested positive/present per pen, by

dividing the number of positive/present results by the total recorded samples in each pen.

Meat quality

Sensory scores for individual panellist were averaged to give a single score per attribute per pig sampled for statistical analysis.

Sensory score sample means and all other sample assessments were considered as independent experimental units in the

statistical analysis of meat quality data.

47

Statistical analysis

Production

Pen means for live weight, feed intake, growth rate, feed conversion ratio, slaughter weight, carcase quality measurements and

within pen standard deviation for growth and carcase quality measurements were subjected to Analysis of Variance (ANOVA)

using the General Linear Model (GLM) in Minitab Statistical Software (Minitab Inc., State College, PA, U.S.A.). Model inputs

included housing system (H), feeding system (F) and an interaction term for feeding and housing (I).

Pen effluent data were subjected to one-way ANOVA to establish the effect of feeding system on waste production.


Pen means for hygiene, lesion, health, behaviour and post-slaughter measurements were subjected to a two-way ANOVA. Model

inputs included housing system (H), feeding system (F) and an interaction term for feeding and housing (I).

Microbial status

All microbial counts from gut samples at the start of the trial were subjected to two-way ANOVA and for colon samples GLM

was used. Model inputs included H, F and I.All microbial counts from gut samples at slaughter were subjected to ANOVA using

GLM. Model inputs included H, F and I.

Viable counts in complete feed samples were subjected to one-way ANOVA for the effect of feeding system.

Bacterial counts in faecal samples were subjected to two-way ANOVA. Model inputs included H, F and I.

Enterobacteraciae in effluent samples were subjected to ANOVA using GLM for the effect of feeding system.

Data obtained for total aerobic and coliform counts in dust samples were subjected to ANOVA using GLM. Model inputs included

H, F and I.

Pen positive rates for Salmonella ELISA and caecal presence were subjected to two-way ANOVA. Model inputs included H, F and I.


Room results for dust and ammonia were subjected to two-way ANOVA, with H and F as model inputs. Pen results were

subjected to ANOVA using GLM for the effect of feeding system (F) on effluent production. Room sample results were subjected

to ANOVA for the effect of feeding system (F) on effluent composition (F).

Meat quality

Sample data from physical, chemical and sensory measurements of meat quality were subjected to ANOVA using GLM. Model

inputs included pig gender, H, F and I.

48

APPENDIX III SYSTEMS TECHNICAL SPECIFICATIONS

Finishing system

Buildings

The finishing buildings have identical shells constructed of a steel frame (33.8m long, 12.30m wide with 2m eaves height at a 15

degree pitch). External walls are constructed from Durox insulated blocks (215mm, U value of 0.6) finished using Fibrocem plaster

coating (3mm).The roofs are constructed with fibre cement with fibreglass insulation giving a U value of 0.7.

Ventilation system

The ventilation and environment in each room is automatically controlled (Euromatic DOL34H, Skov, Denmark) to set maximum

and minimum ventilation, relative humidity (RH) and temperature against occupancy day.

Table 1 Settings for the environmental control system in the finishing buildings

Day Max. ventilation (%) Relative humidity (%) Straw based system: Fully slatted system:

Target temperature (°C) Target temperature (°C)

1 65 55 24 25

7 75 60 22 23

14 85 - 20 21

21 - - 19 20

42 100 75 18 20Minimum ventilation: Summer 20% and Winter 5%.

Each room is equipped with temperature and humidity sensors.

Fresh air is ventilated into each room through three side vents allocated in the external wall above each pen.The vents are fitted

with adjustable flaps controlled by the Skov system.

Stale air is extracted from each room by a single fan located centrally in the roof. Fan speed and airflow are controlled

automatically by the Skov system through adjustment of the exhaust inlet flap under negative air pressure.

Additional heating is provided by two heaters above each pen.These are also automatically controlled by the Skov system.

If in the event of a power cut the flaps and fan go to a default position and the building operates as an ACNV (Automatically

Controlled Natural Ventilation) system.

Environmental data is captured on a computer using Skov software.

49

Internal construction of the fully slatted building,

each pen with independent shallow effluent pit (10 to

14 days storage) for waste monitoring.

Internal layout of the fully slatted building, complete

with concrete slats, central passage and internal

walls, pen divisions and gates made from recycled

high density polypropylene (PP), Panel Plus (51mm).

Internal construction of the straw based building,

with central passage and scraped dunging areas.

Internal layout of the straw based building, with solid

concrete for strawed lying and scraped dunging

areas. Internal walls, pen divisions and gates

(incomplete) made from recycled high density

polypropylene (PP), Panel Plus.

50

Figure 1 Pen layout within each room of the fully slatted building

Figure 2 Pen layout within each room of the straw based building

Location of ad libitum hoppers for pen groups on pelleted dry feed (Trial 1)

X

X

X

1.0m 5.5m

3.7m

X

1.0m 5.8m

3.7m

51

Liquid feeding troughs in the fully slatted (left) and straw based (right) buildings with delivery pipes and sensors

fitted.

Liquid feeding trough

Figure 3 Design and specification of the ad libitum liquid feeding trough

Three dimensional view

SectionShowing detail of divider

Side Elevation300mm deep with lip heightof 220mm. Base and backfixings.

Front Elevation1200mm wide with 2 dividers, 10mm ‘chin bar’ to reduce spillage,Front lip folded down to form safe edge, all other exposed edges with 5mm wire as protection.

52

Feed centre

Figure 4 Schematic layout of feed centre (not to scale)

See page 53 (opposite) for details

27 28 29 30

1 2 3 4 24

13

7 8 95

14

6

10 11 1222

25

23

26

21 20 19 18 17 16 15

Entrance

Fire Exit

Fire Exit

53

System ID Capacity Description

Dry feed storage and milling

1 DS1 5 tonnes Reserve cloth silo

2 DS2 19 tonnes Cloth silo holding whole grain wheat

3 DS3 19 tonnes Cloth silo holding pelleted wheatfeed

4 DS4 19 tonnes Cloth silo holding whole grain barley

5 DS5 5 tonnes Cloth silo holding rapeseed meal

6 DS6 19 tonnes Cloth silo holding soya bean meal

7 S7 1.3 tonnes Cloth bin with load cells holding milled wheat

8 S8 1.3 tonnes Cloth bin with load cells holding milled barley

9 S9 1.3 tonnes Cloth bin with load cells holding milled wheatfeed

10 DS15 0.5 tonnes Metal bin holding mineral and vitamin supplement mix (grower)

11 DS11 0.5 tonnes Metal bin holding mineral and vitamin supplement mix (finisher)

12 DS10 0.5 tonnes Metal bin holding fish meal

13 Hammer mill

14 Dust valve and filter assembly

Liquid feed processing and delivery system (Meyer Lohne, Germany)

15 3000 litres Waste storage tank

16 Tank 3 3000 litres Central processing tank with load cells, receiving all feed ingredient

components, with heating and chilling facilities

17 Tank 4 1500 litres Protein tank with load cells

18 Tank 5 (L1) 3000 litres Insulated fermentation/storage tank with load cells and heating & chilling

facilities

19 Tank 6 (L2) 3000 litres Insulated fermentation/storage tank with load cells and heating & chilling

facilities

20 Tank 1 1000 litres Feeding tank with load cells

21 Tank 2 1000 litres Feeding tank with load cells

22 S44 1000 litres Soya oil pumped into central process tank

23 Positive displacement pumps for liquid feed transfer and delivery

Heating, refrigeration and water supply

24 S41 Water tank

25 Boiler

26 Chiller

Co-product storage and delivery

27 - 30 37, 38, 39 22 tonnes each Tanks for separate storage and delivery of four co-products to central process

and 40 tank

54

GLOSSARY

Nutritional

Enzymes In the context of pig nutrition, enzymes help to breakdown dietary substances, such as starch and protein,

so that they can be more easily absorbed as nutrients.

pH A measure of the acidity or alkalinity of liquids, such as liquid feed.As pH decreases from a neutral value of

7.0, acidity increases.The pH of liquid feed samples from Trial 1 ranged between 4.4 and 5.3.

DE Digestible energy.The total energy in the pig’s food minus that lost in the faeces. DE is usually around 85%

of the total energy present in the pig’s diet.

Lysine The first limiting essential amino acid in a cereal based diet, which must be provided for lean growth by

supplementation with protein rich feed ingredients (e.g. soya bean meal) or synthetic lysine.

NDAF Neutral detergent plus amylase fibre.The cell wall fraction of plant derived feed ingredients, which the pig

is unable to readily digest.

Ethanol Alcohol.

Lactic acid Produced predominately by lactic acid bacteria as a by-product from the fermentation of carbohydrates

(e.g. lactose and glucose). Lactic acid at a concentration of between 100 and 150mmol per litre (or 1 to

1.3%) is highly desirable in the control of Salmonella and other undesirable bacteria such as coliforms in

liquid feeds.

Acetic acid Vinegar acid, which can also be generated during microbial fermentation of liquid feeds. Concentrations

(>30mmol per litre or 0.16%) are undesirable and can reduce feed palatability.

Lipid fatty acids The individual fatty acids found in oils and fats.These are usually a mixture of saturated, mono-saturated

and polyunsaturated fatty acids.

Health and welfare

Acute Phase Proteins Acute-Phase Proteins (APP) are produced mainly by liver cells.The production of these proteins is

dramatically changed by infection, inflammation, and malignancy. Levels are generally regarded as being

sensitive, although non-specific, indicators of inflammation.

PRRS virus Porcine Respiratory and Reproductive Syndrome virus commonly known as “Blue-ear” causes pneumonia

in grower-finishers and abortions, infertility and stillbirths in sows.

C-Reactive protein C-reactive protein (CRP) is considered one of the "major" Acute-Phase Proteins. Increases in response to

insults.

Haptoglobin Haptoglobins are Acute-Phase Proteins and are a group of substances produced by the liver, which bind

free haemoglobin circulating in the blood. Increases in response to insults.

Hyperkeratosis Thickening of tissues such as the skin.

Osteochondrosis Abnormal growth of the cartilage particularly on joint surfaces, which may cause lameness.

Microbiology

Salmonella ELISA An enzyme-linked immunosorbent assay (ELISA) or test, which detects the presence of circulating

antibodies in the pig resulting from exposure to the Salmonella group (or genus) of bacteria.A positive test

does not necessarily indicate that the pig is carrying Salmonella.

Salmonella A group of rod-shaped bacteria found in the pig’s food, gut or faeces, which can be transmitted to humans

through the consumption of contaminated pig meat products and which may cause food poisoning.To

detect the presence of Salmonella in pig feed, the gut or in pig meat, the sample must be subjected to

microbial culture techniques in the laboratory.

Bacterial counts Counts of viable bacteria are made by serially diluting a sample in 10-fold steps, then plating these samples

on agar containing appropriate nutrients. Bacterial colonies are assumed to arise from single cells and the

number of cells is then calculated through the degree of dilution of the sample.

55

Total Aerobic The total aerobic count provides a measure of the number of bacteria capable of growth in air on a

Viable Count general-purpose growth medium.

Total Anaerobic The total anaerobic count provides a measure of the number of bacteria capable of growth in the absence

Viable Count of oxygen on a general-purpose growth medium. Facultative bacteria will appear in both aerobic and

anaerobic total counts.

Lactic acid bacteria A group of Gram-positive lactic-acid-producing bacteria capable of anaerobic growth on MRS agar. In

porcine intestinal samples this includes predominately Lactobacilli with some Bifidobacteria, Streptococci

and Lactococci.

Enterobacteraciae A group of Gram-negative short rod-shaped bacteria found in the intestine of most animals.The group

includes the coliform bacteria as well as related bacteria such as Klebsiella.

Coliform A subgroup of the Enterobacteriaceae which includes Escherichia coli and a number of pathogenic species

such as Salmonella.

Yeast A spore-forming single-celled fungal group with few pathogenic members.Yeast may cause problems in feed

storage and excessive alcohol levels in liquid feeds.

Lawsonia Lawsonia intracellularis is the agent which causes the disease porcine ileitis. It is difficult to isolate from

faeces or gut contents.Their presence is normally detected using molecular techniques.They are rarely

enumerated, the molecular techniques provide only presence or absence data.

Brachyspira Brachyspira (formerly known as Serpulina) is a group (or genus) of bacteria some of which cause colitis

and/or dysentery in pigs. Disease causing species for pigs include B. pilosicoli and B. hyodysenteriae.These

pathogens are difficult to isolate from faeces or gut contents.Their presence is normally detected using

molecular techniques.They are rarely enumerated, the molecular techniques provide only presence or

absence data.

Log 10 As bacteria occur in their millions, laboratory counts are transformed using log 10 so that large numbers

transformation are more manageable. For example 1,000,000 (1 million) in log 10 is expressed as 6, and 100,000 is

expressed as 5 and so forth.All microbial analysis results are presented as Log10 colony forming units (cfu)

per gram or per ml of sample as appropriate.


Emission The release of a potential pollutant, such as dust and ammonia, into the environment from pig production.

Ammonia Ammonia is produced from the microbial breakdown of nitrogen rich compounds found in the pig’s faeces

and urine.Ammonia can be found in the liquid fraction of waste, such as manure and slurry, and is readily

released into the atmosphere.Ammonia is a potential environmental pollutant and there are regulations,

which aim to control emissions from intensively housed pigs.

Ammoniacal nitrogen Nitrogen present within ammonia.

Kjeldahl nitrogen Nitrogen present in all other substances present within effluent (e.g. protein) excluding ammonia.

Meat quality

Minolta Chroma A device used to measure colour based on a light source and silicon photocells to measure reflected light.

Meter This gives a set of numeric values for sample colour. The value given in the results is the saturation value,

which is a measure of the intensity of colour. Higher values indicate a more intense colour (i.e. darker pink

in the case of pork).

Skatole and indole Principle components of boar taint in pig meat, produced in the pig’s gut by bacterial fermentation.A

skatole level greater than 0.25ppm is considered undesirable for consumers.

TBARS "Thiobarbituric acid reactive substances" values are a measure of the degree of rancidity of pig meat fat

samples.Values higher than 1 are generally considered as undesirable in pork.

56

Statistical

Mean Means or averages in the report are weighted means of the observation.They are values from the

statistical analysis, which ensures that no biases have resulted from, for example, an uneven distribution of

animals to a particular treatment.

Level of significance A single asterisk denotes significance at the five per cent level, meaning that such differences could arise by

chance alone, with a probability (P) of 1 in 20.A double asterisk is at the 1% level and a triple asterisk is at

the 0.1% level. Significance between the 5 and 10% level of probability is given as the P value. P values

greater than 10% are left blank.

Lack of significance does not necessarily imply that real differences do not exist, only that in the work

conducted they were not demonstrated or were not large enough to distinguish from the effects of

random variation.

Interaction An interaction (I) between housing system (H) and feeding system (F) implies that the difference between

the two feeding systems was not the same for both housing system. For example in Trial 1, the growth

benefits from liquid feeding over dry feeding were much greater in the straw based compared with the fully

slatted system, giving a statistically significant interaction.

Standard deviation Standard deviation (SD) is a measure of how variable the data are for a given measurement of interest, say

growth rate. In most data sets, around 94% of all values fall within +/- 2 standard deviations either side of

the mean.

Standard error of The standard error of difference (s.e.d.) is a function of the standard deviation and the number of

difference independent observations per treatment mean.As a general guide, two treatment means tend be

significantly different if the difference between the means is twice the s.e.d.

57

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59

ACKNOWLEDGEMENTS

The Finishing Systems Research Programme is funded by Defra and BPEX.

The research participants are:

Acorn House Veterinary Surgery1

Liquid Feeders Research Group2

Meat and Livestock Commission3

Scottish Agricultural College4

Silsoe Research Institute5

University of Newcastle upon Tyne6

University of Nottingham7

University of Plymouth8

Veterinary Laboratories Agency9

This report was compiled by Dr Pinder Gill3, co-ordinator of the research programme, with the support of the following

participants:

Dr Jane Beal8, Professor Peter Brooks8, Dr Phil Cain6, David Chennells1, Dr Rob Davies9, Dr Theo Demmers5, Professor Sandra

Edwards6, Peter Heath9, Dr Kevin Hillman4, Brian Hunt9, Kim Matthews3, Philip McTiffin2, Mike Owen3, Martin Sage2, Kamara Scott6,

Lisa Taylor3, Dr Jayne Thompson3, John Tingey2, Barry Weigleb3, Dr Julian Wiseman7.

The following companies participated in the development of the Stotfold Finishing Systems Research Unit and their provision of

technical support is gratefully received:

Quality Equipment, G.E. Baker (UK) Ltd, Bury St Edmunds, Suffolk

Meyer Lohne GmbH, Lohne, Germany.

© (May 2004) Meat and Livestock Commission.All rights reserved.

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than by reproduction in an unmodified form for the sole purpose of use as an information resource when the MLC is clearly acknowledged as the source, or in accordance

with the provisions of the Copyright, Designs and Patents Act 1988.

Whilst all reasonable care has been taken to ensure that the information contained herein is correct at the time of publication, no representation or warranty is given

nor is to be implied as to its accuracy, nor its fitness for any particular purpose. Use of the information contained in this publication is strictly at the reader’s own risk.To

the fullest extent permitted by law, the MLC excludes liability for any loss or damage, whether direct or indirect, caused by reliance upon any statement or omission in

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BRITISH PIG EXECUTIVE

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www.stotfoldpigs.co.uk

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