Genetic aspects of Wood's lactation curve parameters in Jersey crossbred cattle using Bayesian approach.

The study was undertaken to estimate the genetic parameters of lactation curve parameters of Wood's function in Jersey crossbred cattle using the Bayesian approach. Data on 33,906 fortnightly test day milk yields of 1,718 lactation records of Jersey crossbred cows, maintained at the ICAR-National Dairy Research Institute in West Bengal, were collected over a period of 40 years. The lactation curve parameters including 'a' (initial milk yield after calving), 'b' (ascending slope up to peak yield) and 'c' (descending slope after peak yield) and lactation curve traits, peak yield (ymax), time of peak yield (tmax) and persistency of milk yield (P) of individual cow for each lactation were estimated using the incomplete gamma function (Wood's model) by fitting the Gauss-Newton algorithm as an iteration method using PROC NLIN procedure of SAS 9.3. Variance components and genetic parameters of lactation curve parameters/traits were estimated by a repeatability animal model using the Bayesian approach. Estimates of heritabilities were found to be 0.18 ± 0.05, 0.09 ± 0.03 and 0.11 ± 0.04 for parameters 'a', 'b' and 'c', respectively and 0.24 ± 0.05, 0.12 ± 0.04, and 0.15 ± 0.05 for ymax, tmax and P, respectively. Repeatability estimates were 0.31 ± 0.03, 0.21 ± 0.04 and 0.30 ± 0.04 for parameters 'a', 'b' and 'c' respectively and 0.39 ± 0.03, 0.24 ± 0.03 and 0.37 ± 0.03 for ymax, tmax and p, respectively. Genetic correlations among lactation curve parameters/traits ranged from -0.75 to 0.95. Existence of genetic correlations among lactation curve parameters/traits indicated substantial genetic and physiological relationships among lactation curve parameters/traits of Jersey crossbred cattle.

Effect of superoxide dismutase, catalase, and glutathione reductase supplementation on cryopreservation of Black Bengal buck semen.

The present experiment was carried out with the objectives to study the effects of antioxidants superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GSH) on cryopreservation of Black Bengal buck semen. Semen ejaculates (n = 60) were collected from eight bucks by artificial vagina method and diluted with Tris citrate egg yolk glycerol extender. To study the effect of antioxidants, SOD was added @ 0, 100, and 150 IU/ml; CAT was added @ 0, 200, and 400 IU/ml while GSH was added @ 0, 1, and 2 mM of diluted semen. Semen samples were equilibrated and vapor frozen in liquid nitrogen. Semen samples were evaluated after 48 h of storage for post thaw in vitro characters such as motility, viability, functional membrane integrity, and acrosome integrity. Semen extenders supplemented with SOD @ 100 and 150 IU/ml and GSH @ 1 and 2 mM had a higher (p < 0.01) number of motile cells, viable cells, HOST reacted cells, and acrosome intact cells than their respective controls. Further, semen extenders added with catalase @ 200 and 400 IU/ml had more (p < 0.05) number of viable, HOST reacted cells and significantly higher (p < 0.01) acrosome intact sperm cells than its control group. It can be concluded that supplementation of antioxidants SOD, GSH, and CAT had a beneficial effect on cryopreservation of Black Bengal buck semen.

Influence of pre and postpartum alpha-tocopherol supplementation on milk yield, milk quality, and udder health of Jersey crossbred cows at tropical lower Gangetic region.

BACKGROUND AND AIM: Alpha-tocopherol supplementation influences milk yield, milk quality, and udder health of dairy cows, which needs to be investigated for Jersey crossbred cows at hot-humid climate. Therefore, the present study was framed with an objective to study the effect of pre and postpartum Alpha-tocopherol supplementation on milk yield, milk quality, and udder health status of Jersey crossbred cows at tropical climate. MATERIALS AND METHODS: For this study, 19 similar parity, body condition score, and production level dairy animals were separated randomly into three groups, namely, Control, T1 and T2. Control group (no supplementation) was compared with two treatment groups, namely, T1 and T2. Supplementation of Alpha-tocopherol was done in concentrate fed to the animals (at 1 g/cow/day) 30 days prepartum to 30 days postpartum in T1 and 30 days prepartum to 60 days postpartum in T2 groups. Observations were taken for different parameters up to 5 months of lactation. RESULTS: Statistically analyzed data revealed that overall significantly (p<0.01) more milk production was found in T2, followed by T1 than the control group. Overall significantly (p<0.01) lower somatic cell counts and modified California mastitis tests were recorded in T2, followed by T1 than the control group. Overall significantly (p<0.01), better milk quality in terms of methylene blue reduction test was found in T2, followed by T1 than control groups. Differences in the milk composition of all three groups were non-significant (p>0.05). CONCLUSION: Supplementation of Alpha-tocopherol during prepartum to initial lactation period may enhance milk yield, milk quality, and udder health status of Jersey crossbred cows at the tropical lower Gangetic region.