Response of Rumen Protected Methionine and lysine supplementation on lactation and reproductive performance in periparturient dairy cows.

______ ____ __________________________ _______________ ______ This study was conducted to investigate the effect of supplementing rumen protected methionine (RPM) plus lysine (RPL) on milk production and its composition, nutrient utilization, plasma metabolites and reproductive performance in peri parturient crossbred cows (Bos taurus X Bos indicus). Eighteen crossbred cows were selected and divided into two groups (9 each) on the basis of most probable production ability (MPPA) and lactation number. Animals in group 1 (MPPA 4119 kg) were fed chopped wheat straw, chaffed green maize fodder and concentrate mixture as per requirements (NRC, 2001) whereas, animals in supplemented group 2 (MPPA 4120 kg) were fed same ration as group 1 plus 5 gm RPM and 20 gm RPL, pre partum and 7 gm RPM and 60 gm RPL, postpartum, respectively. The experimental period commenced 40 days before expected date of parturition to 120 days post parturition. During the pre-parturient period, rumen protected methionine and lysine supplemention exhibited higher gross apparent changes in body condition score. Intakes of CP, RDP, RUP, MP, TDN, ME and NEL were similar while duodenal supply of methionine and lysine was increased on supplementation of rumen protected methionine and lysine in pre parturient cows . Plasma triglycerides and VLDL concentration were increased (P<0.05) in prepartum cows on supplementating rumen protected methionine plus lysine. Plasma glucose, phosphatidylcholine, NEFA, vitamin E, cholesterol and BUN were not affected. Plasma amino acids profile of the pre partum cows was not affected on supplementing rumen protected methionine and lysine while plasma methionine, cysteine and lysine concentrations tended to increase on supplementation. During post partum period, fortnightly changes in body weight revealed that there was overall a net loss of 18.59 kg in group 1, whereas there was overall gain of 5.79 kg in group 2. The DM, CP, MP, TDN, ME and NEL intake kg per day as well as per cent body weight was higher in group 2 than that of group 1 lactating cows. Milk yield during supplementation period in group 2 was 17.69 kg/d, which was 11.33 per cent higher (P<0.01) than that of group 1 (15.89 kg/d). There was no effect of supplementation on milk protein, solid not fat (SNF), milk choline and MUN contents in both the groups, whereas milk fat content was higher (P<0.01) by 2.18 per cent in group 2 (4.22%) than that of group 1 (4.13%). The efficiency of utilization of DM, CP, MP, TDN, ME, NEL per kg milk or FCM yield was better in group 2 than that of group 1. The saturated fatty acids, unsaturated fatty acids, mono and poly unsaturated fatty acids in milk fat were similar in group 1 and group 2. Plasma glucose (55.61 and 55.07 mg/dl), phosphatidylcholine (138.57 and 140.98 μg/ml) NEFA (106.80 and 105.77 mg/L), vitamin E (1.01 and 0.90 μg/ ml), cholesterol (193.16 and 198.31 mg/dL) and BUN (18.13 and 18.01 mg/L) concentrations were similar in both the groups. Plasma triglycerides and VLDL concentrations were 13.40 and 16.22 mg/dL and 2.68 and 3.24 mg/dL in group 1 and 2, respectively which were higher (P<0.01) in group 2 than in group 1. Plasma aspartate, glycine, alanine, valine (P<0.05), methionine, cysteine, and lysine (P<0.01) concentrations were increased in cows fed ration supplemented with RPM plus RPL. However, RPM plus RPL supplementation lowered (P<0.05) plasma isoleucine concentration. The plasma prolactin (79.68 and 80.39 ng/L) and growth hormone (6.63 and 6.63 ng/L) concentration were similar in both the groups. The body weight of calves at the time of birth was similar in both the groups. Two cases of premature births were reported in group 1, however, one case was observed in group 2. Four cases of retention of fetal membranes (RFM) were observed in group 1 while only one case was observed in group 2. Higher incidence of metritis in group 1 (3 cases) were recorded whereas only one case was observed in group 2. The time required for commencement of cyclicity was similar (P>0.01) in both the groups. The service period was shorter (P<0.01) by 11.8 days in group 2 than that of group 1, indicating that lesser time was required for the animals in group 2 for conception. AI required for conception was similar in both the groups. The conception rate during the experimental period of 120 days was 55.55 % in group 1 and 66.66 % in group 2. Supplementtion of rumen protected methionine and lysine to high yielding lactating cows during periparturient period was found to be cost effective. The results of the present study showed that the supplementation of rumen protected methionine and lysine improved reproductive performance and lead to efficient use of nutrients at early stage of lactation, which in turn manifested in higher milk yield. In addition, milk fat content was increased, resulting in improvement in the commercial value of milk.