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.

Objective: This study was conducted to estimate the association of age at first calving with first lactation traits as well as lifetime performance traits in Murrah buffaloes.Methods: Data on first lactation and life time performance of Murrah buffaloes (n=679), maintained at ICAR-CIRB, Hisar, India during the period 1983 to 2017, were deduced to calculate heritability estimates, genetic and phenotypic correlation of different first lactation and lifetime traits. The univariate animal model was fitted to estimate variance components and heritability separately for each trait, while bivariate animal models were set to estimate genetic and phenotypic correlations between traits under study.Results: The heritability was high for First Peak Milk Yield (FPY, 0.64±0.08), moderate for Age at First Calving (AFC, 0.48±0.07) and breeding efficiency (BE 0.39±0.09). High genetic correlations of FLTMY (First Lactation Total Milk Yield) with FLSMY (First Lactation Standard (305 days or less) Milk Yield), FPY (First Peak Milk Yield) and FLL (First Lactation Length) was seen. Likewise, genetic correlation of AFC was positive with traits viz. FLTMY, FLL, FDP (First Dry Period), FSP (First Service Period), FCI (First Calving Interval), HL (Herd Life) and PD (Productive Days). Significant phenotypic correlation of FLTMY was observed with traits viz. HL (Herd Life), PL (Productive Life), PD, Total LTMY (Total Lifetime Milk Yield), Standard LTMY (Standard Lifetime Milk Yield). Moreover, positive genetic and phenotypic correlation of FPY was observed with HL, PL, PD, Total LTMY and Standard LTMY.Conclusion: This study reports that age at first calving had positive genetic correlation with FDP, FSP, FCI and UD (Unproductive Days) while, negative association of AFC was observed with FLSMY, PL, Total LTMY, Standard LTMY and BE. This suggests that reduction of age at first calving would results in improvement of lifetime performance traits.

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