Tradotto da: ATTI dell’11° Congresso Multisala SIVAR

Palazzo Trecchi - Cremona - Italia8-9 maggio 20091

USE OF HEPAGEN® IN THE DAIRY COW DURING THE TRANSITION PERIOD: PRACTICAL EXPERIENCES

USE OF HEPAGEN® IN THE DAIRY COW DURING THE TRANSITION PERIOD: PRACTICAL EXPERIENCES

Federico Gorrieri1 - Pier Giorgio Persona2 1DMV LP, Reggio Emilia - 2 DMV, Fatro

INTRODUCTION

During the transition period, conventionally subdivided into close-up (three weeks before calving) and fresh-cow (three weeks after calving), the dairy cow encounters deep metabolic changes that can damage its state of health, and its future milk production, as well as its reproductive career. In particular, the Negative Energy Balance which takes place at the onset of the milk production, causes rapid fatty mobilization, which on the one hand guarantees suffi cient amounts of energy for the production of milk but, on the other, causes a high concentration of NEFA in the blood, and consequently accumulation in the liver, inducing fat infi ltration and, consequently, a reduction in the detoxifying and synthesising functions of the liver. The consequences of this hepatic lipidosis manifest themselves very early in the post-partum, appearing as placental retention, metritis, ketosis, abomasum displacement and mastitis.To prevent fatty infi ltration of the liver, different strategies can be adopted regarding the diet of the cow in the last stage of lactation, during the dry-off period and the close-up period and also management of the groups of animals at the various productive stages.Inside this complex mechanism, the complementary use of a molecule named phenoxy-2-methyl-2-propionic acid (Hepagen®) becomes interesting, whose action, from a biochemical point of view is the activation of PPAR-α (peroxisome proliferator activated receptor-α), which plays a fundamental role as a regulator of energy homeostasis in cases of fatty liver syndrome and metabolic pathologies.More specifi cally, this receptor has been identifi ed as a regulator of the transcription of certain genes participating in lipid catabolism, in the transportation of fatty acids and their entry into the hepatocytes. Recent studies have investigated the possibility that the NEFA can be oxidized into peroxisomes, small sub-cellular bodies present in many body tissues; in particular, it seems that peroxisomal ß-oxidation, involves a greater energy production than that in the mitochondria, which is not under the control of the energy requirements of the cells; therefore, peroxisomal ß-oxidation can represent a good pathway for the oxidation of an excess of fatty acids derived from massive lipomobilisation.

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ß-oxidation in the peroxisomes has also been demonstrated in cattle; in particular it seems that oxidation of around 50% of the NEFA takes place in peroxisomes, and with no limitations caused by a defi ciency of carnitine, essential for the entry of fatty acids into the mitochondria.5 The consequences of the activation of PPAR-α are increased mitochondrial activity, greater peroxisomal ß-oxidation and high hepatic gluco-neogenesis, and therefore a reduced accumulation of triglycerides in the hepatocytes, with, as a consequence, a recovery of liver functions and an increase in energy production. The aim of this trial is an evaluation of the effects of Hepagen® after its administration during the transition period in the dairy cow, considering certain clinical and productive parameters, such as pathologic post-partum dysmetabolisms, ketosis, milk production, % of milk protein and fat and fertility rate.

MATERIALS and METHODS

For the trial, starting from May 2008, 200 dairy cows were recruited belonging to a herd located in the “Pianura Padana”, in Northern Italy, producing milk for transformation into the typical Parmigiano-Reggiano cheese; on the basis of the herd number, the animals were subdivided into two groups of 100 head each: even numbers - treated group, odd numbers - control group.Each group consisted of cows clinically in a good state of health at the time of assignment to the group and were subdivided as follows: 1/3 primiparous, 1/3 second calving and 1/3 multiparous. The recruited animals were fed on the same diet throughout the trial and were kept under the same environmental conditions, considering their productive and reproductive stage.The animals included in the experimental trial calved between June and August 2008.The protocol consisted of a double administration of 50 ml of Hepagen® / per head; the fi rst administration was given 20 days before the expected date of calving, while the second injection was given on the day of calving; the control group did not receive any treatment.The evaluation of the BCS of the animals was routinely performed in the herd and was performed by assigning a score between 1 and 5.The ketosis evaluation was run on a random sample of 20 animals from each group through the use of reactive strips available on the market (Ketolac BHB’- Intervet)4; moreover, at the same time, the percentage milk fat was also determined. Data collection regarding production was performed on the basis of the tabulated monthly functional controls performed by the APA (Local Breeders Association), while the analysis of fertility was conducted through the management data base for each herd.

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RESULTS and DISCUSSION

A) Post-partum pathologiesThe average time of injection in the treated group were the follows: the animals received the fi rst injection 19.7 days before the real calving date: in particular for the primiparous it was 20.25 days, for the secondiparous 17.48 days and for the multiparous 19.48 days.In the treated group the following pathologies were detected:1. Primiparous: 4 cases of primary puerperal metritis and 2 cases of puerperal metritis secondary to dystocia and 2 cases of abomasum displacement.2. Second calving: 2 cases of primary puerperal metritis and 1 case of puerperal metritis secondary to placental retention; 1 case of placental retention without the onset of metritis.3. Pluriparous: 2 cases of primary puerperal metritis and 1 case of puerperal metritis secondary to placental retention (one of these due to a three-calf parturition).No cases of paresis, or milk fever, before or after calving were detected in either group. On the basis of the data collected, it appears evident that the treated animals were less affected by post-partum pathologies than control group.

In particular, double incidence of post-partum pathologies was recorded in the animals belonging to the control group, and this is perfectly in accordance with results reported in previous trials.More specifi cally, an analysis of the data subdivided on the basis of the number of lactations clearly shows that there are no differences between primiparous animals regardless of the group; on the contrary, the untreated elder animals suffered a higher frequency of puerperal metritis and placental retention in comparison to those belonging to the treated group, and the recorded frequency is higher with the increase in the number of calving. This difference in the animals after two or more calving can be explained as a greater in adapting to the metabolic changes in the pre-calving period, probably linked to previous pathologies also involving the liver; the better results showed by the animals belonging to the treated group can be attributed to the benefi cial effects of phenoxy-2-methyl-2-proprionic acid on liver function and, in general on digestive function.Lipid metabolism can compromise the immunological capacity of the cow: the pathogenesis of placental retention and puerperal metritis certainly involves an alteration to leukocyte migration, metabolic disorders and hormonal upsets, all factors strictly connected to the liver function.

Table 1: Post-partum pathologies - comparison between the two groups.

∗χ2 > 2,71: P > 90%**χ2 > 3,84: P > 95%

Pathology

Primary metritisPlacental Retention + metritisMetritis secondary to dystocic calvingAbomasum displacement

Treated (entire group)

83

2

2

Control (entire group)

1511

2

2

χ2

3.26*5.8**

0

0

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B) KetosisThe evaluation of ketosis was conducted through the use of reactive strips available on the market (Ketolac BHB® - Intervet), on 20 animals from each group, randomly chosen every week; this diagnostic kit detects the presence in milk of 13-hydroxy-butyrate.Results were of 0,35 mg / dl as an average value for the treated group and 0,86 mg/dl for the control group; it is interesting to note the positive frequency to the test recorded in the groups: 10% for the treated group and 25% for the control group. In the literature, the reference values for concentrations of 13-hydroxy-butyrate in milk for healthy dairy cows are less than 1 mg /dl, values between 1 and 2 mg / dl for cows affected by sub-clinical ketosis and between 2 and 10 mg / dl in cases of animals suffering from clinical ketosis.The mean values recorded in the two groups clearly differ, although the values recorded are low, but this is in accordance with the historical data of the herd, where clinical cases of ketosis have never been a problem. These data are also in accordance with results from other previous trials, stating that preventive administration of phenoxy-2-methyl-2-propionic acid permitted a reduction in the frequency of sub-clinical ketosis.

C) Fat content in milkAn analysis to establish the percentage of fat in the milk was carried out during the fi rst 5-7 days of milking after calving, on all the recruited cows. The recorded values are expressed as a mean percentage ± standard deviation; treated primiparous 3,81 ± 0,94, control primiparous 3,96 ± 1,02; secondiparous treated 3,99 ± 1,36, secondiparous controls 4,14 ± 1,77; treated pluriparous 3,93 ± 0,93, pluriparous controls 4,40 ± 1.It was clear that the treated animals have a lower milk fat content than control animals: considering that the udder is the usual site for lipogenesis during the peak lactation and that the concentration of fatty acids depends on the lactation stage and lipomobilisation, this could indicate that the treated animals show lower lipomobilisation than control animals, probably due to a better utilization of the NEFA already circulating.

D) BCSThe determination of BSC involved all the animals included in the experimental trial, but the data were processed only for the cows at the second or later calving, because for primiparous animals, obviously, BSC data from the period before calving were not available.From an analysis of these data, no signifi cant differences were noted between the treated and control groups; among the treated groups, 4 cows lost ≥ 0.5 BCS points from the start of drying-off to calving, while in the control group 8 cows lost ≥ 0,5 BSC points during the same period; in both groups, these cows were the ones which later suffered post-partum pathologies.This can be explained by the fact that the great lipomobilisation which took place in these cows produced direct consequences on the liver, altering correct function in this organ and producing direct consequences for the post-partum.

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E) FertilityThe analysis of fertility in the animals included in the experimental trial concerned the calving-1st A.I. and the calving-conception intervals and the values recorded were expressed as mean data ± standard deviation.Calving-1st A.I. interval: globally, the animals belonging to the treated group had a mean value of 60,26 ± 15,96 days, while the animals belonging to the control group showed a value of 60,85 ± 16,04. Considering the animals in terms of the number of lactations, the following data were obtained: treated primparous: 60,68 ± 17,94 days, primiparous controls 55,48 ± 14,22; treated secondiparous 61,7 ± 15,06, secondiparous controls 64,79 ± 17,22; treated pluriparous 54,85 ± 13,19, pluriparous controls 64,38 ± 15,89.A global analysis of the calving - 1st A.I. interval shows that for both groups the fi rst A.I. was practically the same, because both groups formed part of the same herd and they were taken into the trial under the same management conditions (e.g. heat detection) and environmental conditions (e.g. feed); in particular, primiparous controls had an calving - 1st A.I. interval which was better than that in treated animals, while both treated secondiparous animals and multiparous animals showed clearly better values than the controls.Calving - conception interval: globally, the animals belonging to the treated group showed values of 76,39 ± 27,72, while the animals of the control group had a mean value of 89,07 ± 33,84.The calving - conception interval was always in favour of the treated animals rather than the controls, considering the two groups globally and analysing the value in relation to the number of lactations. Moreover, this parameter also tends to improve the higher the number of lactations.

F) ProductionThe analysis of milk production in kg, protein and fat, was conducted taking the values recorded by the monthly control on function run by the APA (Local Breeders Association): lactations were compared with each other and with an equivalent mature cow.Both groups, treated and controls, had a production of around 10 tons, with a content of 3.4 % protein and 3.5 % fat; after data processing, no statistically-signifi cant differences were recorded.

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milk

pro

duce

d in

kg

Milk production

1st control

2nd control

1st control

2nd control

1 T

23,41

23,07

1 C

24,06

25,21

2T

28,39

24,43

2C

24,09

24,09

3+T

27,53

30,26

3+C

26,7

25,1

31

29

27

25

23

21

19

17

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CONCLUSIONS

Over the last decade, the management of the transition period in dairy cows has been extensively discussed, especially as regards the relevance that this period has on the state of health and on production, as well as on the profi tability of the reared cows.The greatest care possible must be given to cows experiencing this phase in terms of quality and quantity of food and water, as well as suitable facilities for preparation of calving and an absence of environmental stressors.Many scientifi c articles have been written about the importance (in economic terms or lack of profi tability) which one or more pathologies which appear at calving could have, but these have their roots in a non-optimal management of the previous lactation and/or drying-off and pre-calving periods.The costs of post-partum pathologies can be divided into direct costs, linked to the fees for veterinarians and the use of drugs, and indirect costs, linked to the wasted milk or the lower quantity of the milk produced, to an increase in the number of open days, or to possible death, culling or imposed slaughter of the same animal.From this control case-study, it can be stated that preventive treatment before calving with phenoxy-2-methyl-2-propionic acid (Hepagen®), was able to improve the calving - conception interval as well to reduce the incidence of port-partum pathologies, in animals which were taken under the same dietary and environmental conditions.It is no less interesting to note that rearing establishments with modern management systems can, during the transition period which is the key phase as regards both reproductive and productive aspects, successfully implement corrective preventive and metabolic actions which reduce the risk and severity of pathologies, the discomfort of the animals and, at the same time, increase the profi tability of the dairy herd.

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