Influence of additive and maternal effects on production and reproduction traits in Murrah buffaloes: Insights from Bayesian analysis.

The aim of this research was to assess genetic parameters for first lactation production and reproduction traits in Murrah buffaloes by employing additive and maternal effects. Data on pedigree and specific traits of 640 Murrah buffaloes were gathered from 1997 to 2020. These traits encompassed first lactation milk yield (FLMY), 305-day first lactation milk yield (305FLMY), first lactation length (FLL), first lactation peak yield (FPY), first service period (FSP), first calving interval (FCI) and first dry period (FDP). Genetic evaluations employed six univariate animal models, accounting for both direct and maternal effects, facilitated by THRGIBBS1F90 and POSTGIBBSF90 programs. Fixed factors included in the analysis were period of calving, season of calving and age at first calving. The Bayesian estimates for direct heritability, derived from the most suitable model, were as follows: FLMY: 0.28 ± 0.01, 305FLMY: 0.30 ± 0.01, FLL: 0.19 ± 0.01, FPY: 0.18 ± 0.01, FSP: 0.12 ± 0.01, FCI: 0.14 ± 0.01 and FDP: 0.12 ± 0.01. Maternal effects were found significant, ranging from 5% to 10%, in first lactation traits under Model 2 and Model 5. Additionally, positive and significant genetic and phenotypic correlations were observed among the studied traits. In conclusion, selection based on 305-day first lactation milk yield suggests potential for genetic enhancement in Murrah buffaloes, advocating its inclusion in breeding programmes to bolster early performance. Also, consideration of maternal influences is necessary for genetic progress of animals.

Sharma R ，Dahiya S ，Bangar YC ，Yadav DC ... -  《-》

Genetic and Phenotypic Trends for Production and Reproduction Traits in Murrah Buffaloes.

The objective of the study was to estimate genetic and phenotypic trends for first lactation production and reproduction traits in Murrah buffaloes. The information of pedigree and targeted traits of 640 Murrah buffaloes was collected for the period from 1997 to 2020. The first lactation production traits included first lactation milk yield (FLMY), 305 days first lactation milk yield (305FLMY), first lactation length (FLL), first lactation peak yield (FPY) whereas reproduction traits included first service period (FSP), first calving interval (FCI) and first dry period (FDP). Genetic and phenotypic trends were estimated. Phenotypic trends for FLMY, 305FLMY, FLL and FPY exhibited as 36.96 ± 8.58 kg/year, 31.93 ± 8.34 kg/year, 1.47 ± 0.55 days/year and 0.12 ± 0.02 kg/year, respectively and respective genetic trends exhibited as 3.73 ± 1.67 kg/year, 1.94 ± 0.76 kg/year, -0.15 ± 0.07 days/year and 0.01 ± 0.01 kg/year, respectively. It was revealed that there were significant (p < 0.05) and positive phenotypic trends for all production traits while genetic trends were significant (p < 0.05) for FLMY and 305FLMY traits. The phenotypic trends of studied reproductive traits indicated that only FDP trait significantly (p < 0.01) decreased (1.87 days/year) over time. For FSP and FCI traits, nonsignificant (p > 0.05) genetic and phenotypic trends indicated no change over time. This study highlighted potential challenges in maintaining reproductive efficiency alongside productivity improvements in Murrah buffaloes.

Sharma R ，Dahiya S ，Bangar YC ，Hada R ，Yadav DC ... -  《-》

Association between age at first calving, first lactation traits and lifetime productivity in Murrah buffaloes.

Tamboli P ，Bharadwaj A ，Chaurasiya A ，Bangar YC ，Jerome A ... -  《-》

Genetic Parameters for First Lactation and Lifetime Traits of Nili-Ravi Buffaloes.

The data on first lactation and lifetime performance records of 501 Nili-Ravi were collected for a period from 1983 to 2017 (35 years) maintained at ICAR-Central Institute for Research on Buffaloes, Sub-Campus, Nabha, Punjab. The data were analyzed to calculate heritability, genetic and phenotypic correlation for first lactation traits, viz., Age at First Calving (AFC), First Lactation Total Milk Yield (FLTMY), First Lactation Standard (305 days or less) Milk Yield (FLSMY), First Peak Milk Yield (FPY), First Lactation Length (FLL), First Dry Period (FDP), First Service Period (FSP) and First Calving Interval (FCI), Herd Life (HL), Productive Life (PL), Productive Days (PD), Unproductive Days (UD), Breeding Efficiency (BE), Total Lifetime Milk Yield (Total LTMY), Standard Lifetime Milk Yield (Standard LTMY), Milk Yield Per Day of Productive Life (MY/PL), Milk Yield Per Day of Productive Days (MY/PD), and Milk Yield Per Day of Herd Life (MY/HL). For estimation of variance component and heritability separately for each trait, the uni-trait animal model was equipped, whereas to estimate genetic and phenotypic correlations between traits, bi-trait animal models were fitted. The estimates of heritability for production and reproduction traits of Nili-Ravi were medium, i.e., 0.365 ± 0.087, 0.353 ± 0.071, 0.318 ± 0.082, 0.354 ± 0.076, and 0.362 ± 0.086 for FLSMY, FDP, FSP, FCI, and AFC, respectively. The estimates of heritability were low, i.e., 0.062 ± 0.088, 0.123 ± 0.090, 0.158 ± 0.090, 0.155 ± 0.091, and 0.129 ± 0.091 for HL, PL, PD, Total LTMY, and Standard LTMY and high, i.e., 0.669 ± 0.096 for BE. Genetic correlation for FLTMY was high with FLL (0.710 ± 0.103), and genetic correlation of FLTMY was high and positive with HL, Total LTMY, MY/PL, and MY/PD while low and positive with PL. Genetic correlation of AFC was low and negative with PL, PD, UD, BE, Total LTMY, Standard LTMY, MY/PL, and MY/PD and negative with MY/HL. Significant positive phenotypic association of FPY was seen with FLTMY, FLSMY, FLL, AFC, HL, Total LTMY, and Standard LTMY. Higher heritability of first lactation traits especially FPY suggests sufficient additive genetic variability, which can be exploited under selection and breeding policy in order to improve overall performance of Nili-Ravi buffaloes.

Tamboli P ，Bharadwaj A ，Chaurasiya A ，Bangar YC ，Jerome A ... -  《Frontiers in Veterinary Science》

Estimation of additive and maternal covariance of production traits in Murrah buffalo.

The study was done to determine additive, maternal and common permanent environmental effects and best-suited model for some production traits using six univariate animal models that differed in the (co)variance components fitted to assess the importance of maternal effect using likelihood ratio test in Murrah buffaloes. Data from 614 Murrah buffaloes related to production traits were collected from history pedigree sheets maintained at the buffalo farm, Department of Livestock Production and Management (LPM), LUVAS, Hisar. The production traits under this study were 305 days milk yield (305DMY), peak yield (PY), lactation length (LL), dry period (DP), lactation milk yield (LMY) and wet average (WA). The heritability estimates were in the range of 0.33-0.44 for 305DMY, 0.25-0.51 for PY, 0.05-0.13 for LL, 0.03-0.23 for DP, 0.17-0.40 for LMY and 0.37-0.66 for WA. Model 1 was considered best for most of the traits, viz., 305DMY, PY, LL, LMY and WA followed by model 2 for DP. Covariance and correlated values within the traits caused inflation of heritability in model 3 and model 6. The maximum covariance between the additive and maternal effect was found in trait LMY, which was 14,183.90 in model 3 and the minimum value was also reported in the same trait for model 6, valued at -3522.37. Multivariate analysis showed that all production traits were moderate to high and positively correlated with each other except for DP, which was low and negative genetic and phenotypic correlated. Spearman's rank correlation coefficients of breeding value among all six models were high and significant, ranged from 0.78 to 1.00 for all the traits except DP, therefore any of the models could be taken into account depending upon the availability of data.

Sharma S ，Dhaka SS ，Patil CS 《-》