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Small Ruminant Research 78 (2008) 41–47

Available online at www.sciencedirect.com

Diet selection and eating behaviour of lactating goats subjected totime restricted feeding in choice and single feeding system

Murat Gorgulu a,∗, Mustafa Boga a, Ahmet Sahin b, Ugur Serbester a,Hasan Rustu Kutlu a, Suat Sahinler b

a Cukurova University, Agricultural Faculty, Department of Animal Science, Adana, Turkeyb Mustafa Kemal University, Agriculture Faculty, Department of Animal Science, Hatay, Turkey

Received 16 January 2008; received in revised form 14 March 2008; accepted 8 April 2008Available online 21 May 2008

bstract

This study was carried out to investigate diet selection and eating behaviour of lactating German Fawn × Hair Crossbred goats inifferent feeding methods and levels. Twenty German Fawn × Hair first backcross does (B1) were allocated into 4 treatment groups2 feeding methods single (TMR) and choice feeding × 2 feeding levels ad libitum and restricted) with 5 replicates. Restrictedeeding was applied only 4 h feed allocation during day. Barley, corn, soybean meal, corn gluten meal, wheat bran and alfalfa hayere feed ingredients for single and choice feeding. Eating patterns, milk yield and composition were determined for 8 weeks. The

ollowing results were obtained: (1) the meal criteria for goats restricted single and choice-fed, ad libitum single and choice-fed wereetermined as 1.00 and 0.63, 12.88 and 10.23 min, respectively. (2) Ad libitum feeding increased meal size, meal length, intermealnterval, total eating duration and decreased eating rate and meal number, compared to restricted feeding (P < 0.01). Choice feedingecreased meal size (P < 0.05), meal length (P < 0.01) and increased eating rate and meal number (P < 0.01), compared to singleeeding. Restricted fed goats decreased intermeal interval in single feeding compared to choice feeding (P < 0.01), but increasedeal number in choice feeding (P < 0.01). (3) Ad libitum choice-fed does made a diet containing 12.79% corn, 35.41% barley,

3.21% wheat bran, 5.35% soybean meal, 1.28% corn gluten meal and 29.80% alfalfa meal while restricted choice-fed does madediet having more corn (27.69%), corn gluten meal (5.62%) and wheat bran (16.17%) and less barley (14.37%) and soybean meal

4.51%). (4) Choice feeding decreased RUP intake (P < 0.05) without affecting milk protein, irrespective to feeding levels, whileaving a tendency to increase in milk yield (14.2%) and 4% FCM (8.8%). (5) Restricted feeding decreased DM, ME, ADF andDF intakes (P < 0.05) with concomitant decreases in 4% FCM, total milk solid, ash and fat compositions (P < 0.05), irrespective

o feeding methods. (6) Choice-fed goats changed their preferences for a possible synchronized nutrient intake during a daytime,

s sorted barley, soybean meal and alfalfa hay from early morning to late afternoon.

It could be concluded that choice-fed goats have the ability to make their diet to meet nutrient requirements and had a tendencyo increase in milk yield. Restriction in feeding time resulted in lower feed intake and milk yield, although the animal changed theireed preference in favour of high quality ingredients and eating pattern with lower meal criterion and intermeal interval.

2008 Elsevier B.V. All rights reserved.

eywords: German Fawn × Hair crossbred goats; Dietary choice; Time restr

∗ Corresponding author. Tel.: +90 322 3386463.E-mail address: gorgulu@cu.edu.tr (M. Gorgulu).

921-4488/$ – see front matter © 2008 Elsevier B.V. All rights reserved.doi:10.1016/j.smallrumres.2008.04.004

iction; Milk production

1. Introduction

The goats offered feed ingredients simultaneously inad libitum feeding condition can select their optimum

minant

42 M. Gorgulu et al. / Small Ru

diet to meet their nutrient requirements, correspond-ing to their physiological status. They consume highamount of concentrate without suffering any digestiveproblem by balancing fiber intake with creating syn-chronicity among feed ingredients in respect to energyand nitrogen supply to the rumen and/or host animal(Fedele et al., 2002; Gorgulu et al., 2003; Yurtseven andGorgulu, 2004). Choice feeding improves milk yield indairy goats when offered feed ingredients with propercombinations maintaining their nutrient requirements(Fedele et al., 2002; Gorgulu et al., 2003; Yurtseven andGorgulu, 2007). Thus choice feeding could be evaluatedan economic and alternative feeding system for smallruminants. Rodriguez et al. (2007) tested choice feedingfor lambs and proved that it was an alternative to con-ventional feeding system for fattening lamb in feedlotcondition.

In conventional goat production, the goats are pas-tured in early and late hours of the daytime and feedingwith restricted amount of concentrate during milkingor after pasture. This system may lead goats to sufferfrom inadequate nutrient intake and consequently poorperformance. The ability and/or good wisdom of smallruminants for diet selection in choice feeding situationmay prevent the above referred problems by selectinga higher quality food to counteract the time restrictionin feeding. There is, however, insufficient informationabout the ability of feed preferences and lactating perfor-mance in goats when feed ingredients are offered freelyin ad libitum and restricted conditions throughout aday.

On the other hand, few studies on diurnal eat-ing pattern (daily feed intake, number of visits, meallength, intermeal interval, eating rate) of dairy cows(Tolkamp et al., 1998, 2000; DeVries et al., 2003)in single feeding condition, but not for dairy goats,either in single or choice feeding condition have beenreported. Intermeal interval for dairy cows was deter-mined as 20 min (Metz, 1975; Tolkamp and Kyriazakis,1999) by using frequency distribution. Rossi et al.(1999a,b) defined “meal” as feed removal exceeding5 g and separated to two meals between each otherby taking a 15 min period of not-eating as the cri-terion. However, there is still insufficient informationregarding meal pattern of dairy goats subjected to dif-ferent feeding managements. Therefore, the aim of thepresent study was to investigate (1) whether goats wouldhave the ability to maintain milk yield and nutrient

intake during either free or restricted access to feed-stuff, (2) to determine meal criterion and diurnal feedingpattern in dairy goats under the above feeding condi-tion.

Research 78 (2008) 41–47

2. Materials and methods

In the study, 20 German Fawn × Hair first backcrossdoes (B1), having twin kids, in the second lactation wereused. Twenty does weighing 54.8 ± 1.6 kg, yielding daily2.72 ± 0.20 kg milk and being 25 ± 0.7 days after postpartum,were allocated into four treatment groups. Each goat withineach treatment was one replicate.

Treatment groups were set up according to 2 × 2 factorialarrangements to evaluate two feeding methods (single feed-ing and choice feeding) in two feeding levels (ad libitum andrestricted feeding) as main effects. Restricted feeding wasapplied by allowing the goats to reach feed only from 09:00 to11:00 and from 15:00 to 17:00 in a day, while there were no timerestrictions applied in ad libitum groups. Barley, corn, soybeanmeal, corn gluten meal, wheat bran and alfalfa hay were usedas feed ingredients for both single and choice-fed groups. Sin-gle diet (TMR) was prepared according to diet selection dataobtained from the study of Yurtseven and Gorgulu (2007) forthe goats in same breeds.

Each goat was housed in a 1.5 m × 1.5 m sized pen havingone trough sizing 0.4 m × 1.2 m with 15-L bucket for freshwater. Feed troughs of animals in choice feeding groups weredivided into six equal parts to offer feed ingredients separatelybut simultaneously. The does were divided into four groups ofsimilar mean live weight and milk yield.

The experiment lasted for 8 weeks. Before the experi-ment, choice does were habituated organoleptic properties andmetabolic consequences of feed ingredients for a week. Wheatbran, corn and barley, soybean meal, and corn gluten meal alongwith alfalfa hay (1–2 cm particle size) were offered to choicedoes in the first, second and third day of the week. This proce-dure was repeated again for following three days to guaranteefamiliarisation of feedstuffs by goats. On 7th day, all ingredi-ents were offered simultaneously to be continued throughoutexperimental period. At the same time, single-fed does wereaccustomed to organoleptic properties of single diet. Each feedingredient, except alfalfa hay, was mixed with limestone, saltand vitamin–mineral mixture at the levels present in the controldiet in order to ensure the micronutrients intakes of choice doesand, also, to prevent any possible effect of micronutrients onfeed selection. Fresh water was available during experimentalperiod.

The chemical composition of feed ingredients was deter-mined according to the standard AOAC (1998) procedures.NDF and ADF were analyzed by using ANKOM fiber ana-lyzer (Van Soest et al., 1991). Metabolisable energy contentsof the diets were calculated using the table values of the feedingredients published by NRC (1981). Ingredient compositionof TMR and its chemical contents are given in the first columnof Table 1.

Live weight change, milk yield and feed intake were deter-mined weekly after training period. Feeds were offered adlibitum to individual goat everyday, but recorded weekly.Daily refusals were given to the animal on the followingday by adding fresh feed or feed ingredients, but on last

M. Gorgulu et al. / Small Ruminant Research 78 (2008) 41–47 43

Table 1The proportional content of feed ingredients and macronutrients in single diet (TMR) or diets made by goats subjected to ad libitum and restrictedfeeding (mean ± S.E.D., %)

Feeding methods Single feeding Choice feeding P-valuee

Feeding levels Restricted and ad libitum Restricted Ad libitumFeed ingredients/diets Single diet (TMR)d Goat-made diet

Corn (C) 15.00 27.69 ± 10.03 12.79 ± 2.82 0.19Barley (B) 26.39 14.37 ± 6.64 35.41 ± 3.80 0.02Wheat bran (WB) 16.06 16.17 ± 7.36 13.21 ± 1.18 0.70Soybean meal (SBM) 3.00 4.51 ± 2.41 5.35 ± 3.10 0.83Corn gluten meal (CGM) 7.39 5.62 ± 1.97 1.28 ± 0.56b 0.06Alfalfa hay (A) 30.00 29.49 ± 1.64 29.80 ± 0.65 0.85Limestonea 1.55 1.55 ± 0.04 1.55 ± 0.01 0.84Salta 0.51 0.51 ± 0.04 0.51 ± 0.00 0.87Premixa,c 0.10 0.09 ± 0.00 0.10 ± 0.00 0.14

Macronutrient content (%)DM 90.19 89.87 ± 0.18 90.35 ± 0.09 0.04ME (Mcal/kg DM) 2.58 2.61 ± 0.06 2.58 ± 0.01 0.62CP 18.73 17.82 ± 2.03 16.68 ± 1.27 0.64RUP 6.93 5.99 ± 0.95 4.34 ± 0.33b 0.13ADF 19.75 19.39 ± 1.17 19.62 ± 0.19 0.85NDF 32.55 31.65 ± 2.32 32.63 ± 0.39 0.68Crude ash 10.24 10.47 ± 0.48 9.94 ± 0.13 0.31Ether extract 3.08 3.30 ± 0.19 2.87 ± 0.08b 0.07

a These feed additives were added to single diet while they were selected indirectly with barley, corn, soybean meal and corn gluten meal.b Denotes the difference between the diets selected by does and single diet based on one sample t-test (P < 0.05).c Each kilogram vitamin–mineral premix provides 8.000.000 IU vitamin A, 1.000.000 IU vitamin D3, 30 g vitamin E, 50 g Mn, 50 g Zn, 50 g Fe,

10 g Cu, 150 mg Co, 800 mg I and 150 mg Se.restric

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d Man-made diet was offered to the both ad libitum fed and the feede Shows the significance in differences between the diets selected b

ay of week, animal was allowed to finish the refusals and,hen, offered fresh feed or feed ingredient. Animals were

ilked by hand at 07:00 in the morning and at 14:00 in thefternoon and milk samples were taken from morning milknd, then, milk fat were determined by Gerber method. Milkamples were also analyzed for dry matter, ash, milk pro-ein, NPN, casein nitrogen according to AOAC (1998). Theest of the nitrogen fraction was determined by calculation.actose was obtained by subtracting fat plus protein fromilk organic matter as described by Sanz Sampelayo et al.

1998).To record diurnal eating pattern of does, a prototype record-

ng system was developed and set up including six scales0 ± 0.005 kg capacity and connected to a computer witherial multiplier. The system recorded meal size and mealength for each balance with getting stability after 5 s from

shift in the balance weight for 24 h in a day for ad libi-um fed does and for 4 h (from 09:00 to 11:00 and from5:00 to 17:00) in a day for time restricted fed does. As

nly one prototype system was owed in the experimentallace, a doe from each treatment group was kept in a realime data recording system once a week for a day during 8eeks experimental period. The data recorded for each weekere taken as replicates for the doe from each treatment

ted goats.es fed ad libitum and restricted.

groups. Meal criteria were calculated as the point at whichthe probability density functions of the final two populationscross from the parameters of the two and three-populationGaussian models which minimizes the mis-assignment ofintervals to the wrong populations (Tolkamp et al., 1998;Tolkamp and Kyriazakis, 1999; Yeates et al., 2001). The mod-els were fitted using nonlinear curve fitting in GraphPad Prism(2005, Version 4.03) to the pooled and loge-transformed inter-val lengths (expressed in second) between feeding events.Meal criterion for experimental groups restricted single feed-ing, restricted choice feeding, ad libitum single feeding andad libitum choice feeding were determined as 1.00, 0.63,12.88 and 10.23 min, respectively and accordingly, eatingpatterns of does (eating rate, meal size, meal length, inter-meal interval, meal number and total eating duration) weredetermined for these experimental groups. Eating frequencyin Fig. 1 was determined by counting number of visitsto feed container by each doe kept in the recording sys-tem.

Data obtained in the experiment were analyzed by GLMprocedure of SPSS with Duncan’s Multiple Range Test. Thedifferences between the diets selected by does and single dietwas tested by one sample t-test (Windows version of SPSS,release 10.01).

44 M. Gorgulu et al. / Small Ruminant

Fig. 1. Time dependent eating frequency of the does fed ad libitum(CF: choice feeding, TMR: single feeding).

Fig. 2. The proportional intake of feed ingredients by ad libitumchoice-fed does. A: alfalfa hay, B: barley, CGM: corn gluten meal,C: corn, WB: wheat bran, SBM: soybean meal.

ing duration (125.94 min vs. 135.52 min, P = 0.08) in

Fig. 3. The proportional intake of feed ingredients by does subjectedto restricted feeding. A: alfalfa hay, B: barley, CGM: corn gluten meal,C: corn, WB: wheat bran, SBM: soybean meal.

3. Results

The experimental results are given in Table 1 (dietselection), Table 2 (milk yield and composition), Table 3(eating pattern) and Figs. 2 and 3 (diet selection).

Research 78 (2008) 41–47

Table 1 shows that ad libitum choice-fed does madea diet containing less corn, corn gluten meal, and wheatbran and higher barley and soybean meal proportion-ally in comparison to those of the group’s offered thesingle diet without any statistical difference. Also, theydid not change CP, ADF and NDF intakes. Choice-fed does tended to increase DMI (2.98 kg day−1 vs.2.86 kg day−1), reflecting to a tendency to increasein fat corrected milk (FCM) yield (2.56 kg day−1 vs.2.18 kg day−1) but poorer milk production efficiency(0.91 MY/DMI vs. 1.18 MY/DMI) (Table 2), comparedto ad libitum single-fed goats.

Choice feeding decreased RUP intake (P < 0.05) inboth feeding levels ad libitum and restricted feedingwithout affecting other macronutrient intakes in lactatingdoes.

Restricted choice-fed does made a diet contain-ing higher corn, soybean meal and less barley andcorn gluten meal proportionally compared to restrictedsingle-fed does without any statistical difference. Whencompared to ad libitum choice-fed does, restrictedchoice-fed does tended to select higher amounts of cornand corn gluten meal, but similar CP, ADF and NDFintakes (Table 1). However, restricted choice-fed doeswere not able to increase FCM yield (1.66 kg day−1 vs.2.56 kg day−1, P < 0.05) as closer to what ad libitumchoice-fed does did (Table 2).

Restricted feeding decreased DM, ME, ADF andNDF intakes (P < 0.05) with resulting decreases in4% FCM, total milk solid, ash and fat compositions(P < 0.05) irrespective of feeding methods whereaschoice feeding had no effects on milk yield and com-position.

Table 3 shows that ad libitum choice-fed doesincreased eating rate (13.04 g min−1 vs. 7.82 g min−1,P < 0.01) and meal numbers (17.63 vs. 13.25, P < 0.01)while decreased intermeal interval (50.72 min vs.76.91 min, P < 0.05), meal size (167.07 g vs. 203.42 g permeal, P < 0.05), meal length (18.78 min vs. 33.08 min,P < 0.01) and total eating duration (328.94 min vs.434.74 min, P = 0.08) compared to ad libitum single-feddoes.

Restricted choice-fed does increased meal number(33.25 vs. 20.50, P < 0.01), intermeal interval (11.12 minvs. 6.03 min, P < 0.05) and eating rate (19.97 g min−1

vs. 12.70 g min−1, P < 0.01) while decreased meal size(63.60 g vs. 80.35 g per meal, P < 0.05), meal length(3.79 min vs. 6.97 min per meal, P < 0.01), and total eat-

comparison to restricted single-fed does (Table 3).Feeding method and feeding level interaction affected

intermeal interval (P < 0.01) and meal number signif-

M. Gorgulu et al. / Small Ruminant Research 78 (2008) 41–47 45

Table 2The effect of single or choice feeding in ad libitum or restricted level on milk yield and composition

Feeding methods (FM) Single feeding (TMR) Choice feeding (CF) P-value

Feeding level (FL) Restricted Ad libitum Restricted Ad libitum S.E.D. FM FL FM × FL

Milk yield (MY, kg/day) 2.31 2.63 2.30 3.34 0.35 0.34 0.07 0.324% FCM (kg/day) 1.69b 2.18ab 1.66b 2.56a 0.27 0.52 0.02 0.45BWC (g/day) 32.78 33.85 86.64 60.85 26.05 0.14 0.64 0.61DMI (kg/day) 2.43b 2.86ab 2.63ab 2.98a 0.15 0.30 0.01 0.76MPE (DMI/MY) 1.05 1.18 1.40 0.91 0.20 0.85 0.38 0.14MEI (Mcal/day) 6.28b 7.41ab 6.88ab 7.70a 0.39 0.26 0.02 0.69CPI (g/day) 455.35 537.35 470.89 499.69 45.85 0.81 0.24 0.57RUPI (g/day) 168.48ab 198.82a 157.12ab 129.15b 16.98 0.03 0.94 0.10ADFI (g/day) 479.99 566.43 512.03 582.88 33.50 0.48 0.03 0.81NDFI (g/day) 791.14 933.62 841.00 972.63 60.86 0.47 0.03 0.93

Milk compositionTotal solid (%) 10.88ab 11.28a 10.43b 11.07a 0.18 0.08 0.01 0.50Ash (%) 0.61ab 0.64ab 0.60b 0.67a 0.02 0.55 0.03 0.32Protein (%) 3.81 3.59 3.54 3.54 0.10 0.14 0.30 0.30Fat (%) 2.29ab 2.86a 2.14b 2.50ab 0.18 0.18 0.02 0.57Lactose (%) 4.18 4.20 4.15 4.37 0.09 0.41 0.17 0.27

FCM: fat corrected milk, BWC: body weight change, DMI: dry matter intake, MPE: milk production efficiency, MEI: metabolisable energy intake,C ADFI:n statisticf

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PI: crude protein intake, RUPI: rumen undegradable protein intake,itrogen. a,bDifferent superscripted letters within the same row showeeding level (P < 0.05).

cantly (P < 0.05), as evidenced that restricted goatsecreased intermeal interval in single feeding comparedo choice feeding (P < 0.01) but increased meal number

arkedly (P < 0.01) in choice feeding (Table 3).

. Discussion

The results obtained in the current study showedhat lactating goats were able to make a diet to meetheir nutritional requirements when they are offered feedngredients on self selection basis, even though when

able 3ating behaviour of goats in different feeding methods (single vs. choice feedystem throughout 8 weeks

eeding methods (FM) Single feeding (TMR) Choic

eeding level (FL) Ad libitum Restricted Ad lib

eal criterion* (min) 12.88 1.00 10.23ating rate (g/min) 7.82c 12.70b 13.04eal size (g intake/meal) 203.42a 80.35c 167.07eal length (min/meal) 33.08a 6.97c 18.78

ntermeal interval (min) 76.91a 6.03c 50.72eal number 13.25c 20.50b 17.63

otal eating duration (min/day) 434.74a 135.52c 328.94

,b,cDifferent superscripted letters within the same row show the statistical diffevel (P < 0.05).

* This parameter was obtained from the data recorded for a doe from each t

ADF intake, NDF: NDF intake, DM: dry matter, NPN: non-proteinal difference between them with respect to either feeding method or

they were subjected to time restriction for feeding. Thesuccess in diet selection by choice-fed goats can beexplained by hourly arrangements in feed intake and dietselection as shown in Figs. 1–3.

The does fed ad libitum exhibited intensive feed-ing activity near sunrise (08:00–11:00) and sunset(17:00–19:00) (Fig. 1). Fedele et al. (2002) observed

that does maximized feed intake at 07:00 and 17:00. Thereason of high feeding activity during sunrise and sunsetis, more likely, an optimal solar radiation and tempera-ture during these periods because of warm season when

ing) and levels (ad libitum vs. restricted) set in the real time recording

e feeding S.E.D. P-value

itum Restricted FL FM FL × FM

0.63 – – –b 19.97a 1.15 0.00 0.00 0.38b 63.60c 12.04 0.00 0.04 0.42b 3.79c 2.64 0.00 0.00 0.05b 11.12c 4.76 0.00 0.04 0.00bc 33.25a 1.87 0.00 0.00 0.04

b 125.94c 31.84 0.00 0.08 0.14

erence between them with respect to either feeding method or feeding

reatment for a day of the total 8 weeks experimental period.

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46 M. Gorgulu et al. / Small Ru

the current experiment was conducted. Also, ad libi-tum fed does, especially those on choice-fed, extendedtheir feeding activity much wider time in the afternooncompared to the morning, more likely, due to reachingsatiety by consuming fast and high amount of feed in themorning.

The does kept in the real time recording system pre-ferred barley in early time, around 08:00 am in ad libitum(Fig. 2) and 09:00 am in restricted feeding condition(Fig. 3). The preferences of feed ingredient were sortedby animals as barley, soybean meal and alfalfa hay fromthe beginning to the end of the cycle. Barley preferencedecreased during feeding cycle gradually and soybeanmeal (protein) preference increased in the same courseby the choice-fed does irrespective of the feeding lev-els. This preference was supported by Leibowitz (1992)and Kronberg and Malechek (1997), who reported thatmammals prefer carbohydrate during early hours of thefeeding cycle, whereas appetite for protein increasesgradually over the course of active cycle. Barley is ahighly degradable starch source and it can create fastand effective feedback signal in the rumen and body ofanimals. Other preferences during later phase of the daywere concomitant with the minimization of discomfortin the rumen condition and nutrient balance in the rumenand/or host animal (Forbes, 2001; Gorgulu et al., 2003;Yurtseven and Gorgulu, 2004).

Restricted does consumed feed very quickly in themorning, extended their feeding activity to longer periodin the afternoon and selected corn (having high MEcontent with slow degradable starch source) and CGM(having high protein content with slow rumen degrad-able protein source) among the feed ingredients, morelikely, to compensate the energy and protein require-ments for rumen microorganisms and host animal duringfeed restriction periods. Although the diet selected bythe does in choice feeding group is highly nutritious,those does did not respond better to milk yield. Thesepreferences could be attributed to needs optimizing rumi-nal condition mainly and changes to nutrient partitionbetween mammary tissue and body fat tissues. This couldbe seen from the tendency in higher live weight gainin choice-fed does if they fed restricted (Table 2). Thecorn-based diets could supply more propionate and glu-cose resulting in increase in plasma insulin, which canincrease body condition and fat accretion (Schmidely etal., 1999; Goetsch et al., 2001).

Ad libitum choice-fed does did make a diet having

lower RUP content than other experimental groups. Thismay be explained that ad libitum choice-fed does mayhave consumed protein for their symbiotic microorgan-ism because of having more time to compensate their

Research 78 (2008) 41–47

protein requirement for milk, but time restricted choice-fed does tried to increase RUP intake which is known tobe ready for absorption as the animal had a limited timeto do so.

Restricted does increased meal numbers what ad libi-tum fed goats did, with a concomitant increase in cornconsumption. If they had preferred barley to corn, theycould have suffered from acidosis due to their highlydegradable starch (Aldrich et al., 1993; Khorasani et al.,1994; Casper et al., 1999). It is well known that ruminantscould change their diet preference to minimize imbal-ances in ruminal condition (Forbes, 2001; Fedele et al.,2002; Gorgulu et al., 2003).

Expectantly, restricted feeding decreased DM, ME,ADF and NDF intakes, reflecting to lower total solid,fat and ash contents in milk in comparison to ad libi-tum feeding, irrespective to feeding methods. Of course,restricted does were allowed to eat feed 6 times lesserperiod than that of ad libitum does. In the current study,choice feeding improved nutritional status of the doesby increasing DM, ME, ADF and NDF intakes, irrespec-tive to feeding levels. This was evidenced by a moderateincrease in milk yield about 14.2% and 4% FCM about8.8% with an improved MPE when compared to single-fed does. This increase in FCM and milk fat content withthe increase in feeding level could be a reflection of thegained nutritional status of the does by ad libitum feeding(Sanz Sampelayo et al., 1998; Yurtseven and Gorgulu,2004). The results obtained in this study and our previousstudies (Gorgulu et al., 2003; Yurtseven and Gorgulu,2007) showed that choice feeding have a potential toincrease lactating performance. It has also been reportedthat choice feeding increased fattening performance inlambs (Gorgulu et al., 1996). Additionally, Rodriguez etal. (2007) reported that choice feeding could be an eco-nomic and applicable feeding method in practical feedlotcondition.

Choice feeding increased eating rate (13.04 vs. 7.82for ad libitum feeding; 19.97 vs. 12.70 for restrictedfeeding) compared to single feeding. These could beexplained that more choices and ad libitum feed avail-ability may give advantages to the does to do feedingactivity more liberally. Furthermore, goats are moreselective than other livestock in feeding activity (VanSoest, 1982); these may be incentive for goat to con-sume feed in shorter interval and higher incidence. Morelikely, to make precise dietary choices, present feedrestricted goats increased meal number by making sec-

ondary meals (Table 3) compared to ad libitum fed goats.Above all, the meal criterion was determined as 0.63 minin restricted choice-fed goats. It was clearly understoodthat restricted goats only had totally 4 h in a day for

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M. Gorgulu et al. / Small Ru

eed allowance to compensate their nutritional require-ents for milk production and used about 52–56% of this

llowed time for eating while ad libitum fed goats usednly 22–30% of this time. Actually, goats eat during twoong periods per day called main meals separated by sev-ral smaller meals called secondary meals (Abijaoudet al., 1999). Goats substituted one feed with anotheraking a precise choice (Fedele et al., 2002).It could be concluded that choice-fed goats have the

bility to make their diet to meet nutrient requirementsnd had a tendency to increase in milk yield. Restrictionn feeding time resulted in lower feed intake and milkield, although the animal changed their feed preferencen favour of high quality ingredients (for energy; corns. barley, for protein; corn gluten vs. soybean meal) andeeding pattern with lower meal criterion (0.82 min vs.1.6 min) and intermeal interval (8.6 min vs. 63.8 min).

cknowledgements

The authors are thankful to staffs of Research andpplication Farm of Cukurova University, Agriculturalaculty for their technical contribution and also to Scien-

ific Research Fund of Cukurova University for financialupport under the project number ZF2004BAP6.

eferences

bijaoude, J.A., Morand-Fehr, P., Bechet, G., Brun, J.P., Tessier, J.,Sauvant, D., 1999. A method to record the feeding behaviour ofgoats. Small Rumin. Res. 33, 213–221.

ldrich, J.M., Muller, L.D., Varga, G.A., Griel, L.C., 1993. Non-structural carbohydrate and protein effects on rumen fermentation,nutrient flow, and performance of dairy cows. J. Dairy Sci. 76,1091–1105.

OAC, 1998. Official Methods of Analysis. 16th ed., 4th Revision,Association of Official Analytical Chemists, Washington DC.

asper, D.P., Maiga, H.A., Brouk, M.J., Schingoethe, D.J., 1999. Syn-chronization of carbohydrate and protein sources on fermentationand passage rates in dairy cows. J. Dairy Sci. 82, 1779–1790.

eVries, T.J., von Keyserlingk, M.A.G., Weary, D.M., Beauchemin,K.A., 2003. Measuring the feeding behavior of lactating dairy cowsin early to peak lactation. J. Dairy Sci. 86, 3354–3361.

edele, V., Claps, S., Rubino, R., Calandrelli, M., Pilla, A.M., 2002.Effect of free-choice and traditional feeding systems on goat feed-ing behaviour and intake. Livest. Prod. Sci. 74, 19–31.

orbes, J.M., 2001. Consequences of feeding for future feeding. Comp.Biochem. Physiol. Part A 128, 463–470.

oetsch, A.L., Detweiler, G., Sahlu, T., Puchala, R., Dawson, L.J.,2001. Dairy goat performance with different dietary concentratelevels in late lactation. Small Rumin. Res. 41, 117–125.

orgulu, M., Kutlu, H.R., Demir, E., Ozturkcan, O., Forbes, J.M.,1996. Nutritional consequences of free choice among feed ingre-dients by Awassi lambs. Small Rumin. Res. 20, 23–29.

orgulu, M., Guney, O., Torun, O., Ozuyanık, O., Kutlu, H.R., 2003.An alternative feeding system for dairy goats: effects of free-choice

Research 78 (2008) 41–47 47

feeding on milk yield and milk composition in early lactation ofDamascus goats. J. Anim. Feed Sci. 12, 33–44.

Khorasani, G.R., de Boer, G., Robinson, B., Kennelly, J.J., 1994.Influence of dietary protein and starch on production andmetabolic responses of dairy cows. J. Dairy Sci. 77, 813–824.

Kronberg, S.L., Malechek, J.C., 1997. Relationship between nutritionand foraging behavior of free-ranging sheep and goats. J. Anim.Sci. 75, 1756–1763.

Leibowitz, S.F., 1992. Neurochemical–neuroendocrine systems in thebrain controlling macronutrient intake and metabolism. TrendsNeurosci. 15, 491–497.

Metz, J.H.M., 1975. Time Patterns of Feeding and Ruminationin Domestic Cattle. Communications Agricultural University,Wageningen.

NRC, 1981. Nutrient Requirements of Goat. National Academy Press,Washington, DC.

Rossi, R., Del Prete, E., Scharrer, E., 1999a. Effect of the H1-histaminereceptor agonist betahistine on drinking and eating behaviour inpygmy goats. Physiol. Behav. 66, 517–521.

Rossi, R., Del Prete, E., Rokitzky, J., Scharrer, E., 1999b. Circadiandrinking during ad libitum and restricted feeding in pygmy goats.Appl. Anim. Behav. Sci. 61, 253–261.

Rodriguez, A.B., Bodas, R., Fernandez, B., Lopez-Campos, O., Man-tecon, A.R., Giraldez, F.J., 2007. Feed intake and performance ofgrowing lambs raised on concentrate-based diets under cafeteriafeeding systems. Animal 1, 459–466.

Sanz Sampelayo, M.R., Perez, L., Boza, J., Amigo, L., 1998. Forage ofdifferent physical form in the diets of lactating Granadina Goats:nutrient digestibility and milk production and composition. J. DairySci. 81, 492–498.

Schmidely, P., Lloret-Pujol, M., Bas, P., Rouzeau, A., Sauvant, D.,1999. Influence of feed intake and source of dietary carbo-hydrate on milk yield and composition, nitrogen balance, andplasma constituents of lactating goats. J. Dairy Sci. 82, 747–755.

Tolkamp, B.J., Allcroft, D.J., Austin, E.J., Nielsen, B.L., Kyriazakis,I., 1998. Satiety splits feeding behaviour into bouts. J. Theor. Biol.194, 235–250.

Tolkamp, B.J., Kyriazakis, I., 1999. To split behaviour into bouts, log-transform the intervals. Anim. Behav. 57, 807–817.

Tolkamp, B.J., Schweitzer, D.P.N., Kyriazakis, I., 2000. The biologi-cally relevant unit for the analysis of short-term feeding behaviorof dairy cows. J. Dairy Sci. 83, 2057–2068.

Van Soest, P.J., 1982. Nutritional Ecology of the Ruminant. O. and B.Books, Corvallis, OR.

Van Soest, P.J., Robertson, J.B., Lewis, B.A., 1991. Methods for dietaryfiber, neutral detergent fiber, and nonstarch polysaccharides in rela-tion to animal nutrition. J. Dairy Sci. 74, 3583–3597.

Yeates, M.P., Tolkamp, B.J., Allcroft, D.J., Kyriazakis, I., 2001.The use of mixed distribution models to determine bout criteriafor the analysis of animal behaviour. J. Theor. Biol. 213, 413–425.

Yurtseven, S., Gorgulu, M., 2004. Effects of grain sources and feedingmethods, free-choice vs total mixed ration, on milk yield and com-position of German Fawn × Hair crossbred goats in mid lactation.

Yurtseven, S., Gorgulu, M., 2007. The effects of multiple choices forgrain and protein sources differing in ruminal degradability on dietselection and performance of lactating dairy goats. J. Anim. Prod.48, 7–14.