Genetic parameters of first lactation production traits and test day milk records in Hardhenu cattle

Abstract

This study employed the 486 Hardhenu crossbred cattle, focusing on first production traits and test day milk yields collected from history-pedigree records maintained at the  Department of Animal Genetics and Breeding (AGB) at Lala Lajpat Rai University of Veterinary and Animal Sciences (LUVAS) in Hisar, to estimate the genetic parameters of production performance traits. The overall least -squares means for age at first calving (AFC), first lactation milk yield (FLMY), first lactation milk yield at 300 day (FMY300D), peak yield (PY), first lactation length (FLL), first dry period (FDP), first service period (SP), first calving interval (FCI) were 1232.95±11.80 days, 2806.95±60.1 kg, 2595.38±46.99 kg, 11.96±1.84 kg/day, 303.77±3.45 days, 113.02 ±4.28 days, 126.51±3.19 days, 410.12±3.56 days, respectively. The overall least-squares means for different test days milk records were 5.16±0.15, 8.43±0.18, 9.55±0.18, 10.02±0.17, 9.89±0.17, 9.03±0.14, 7.92±0.15, 6.96±0.16, 5.9±0.17 and 4.19±0.11 kg/day for TD₁, TD₂, TD₃, TD₄, TD₅, TD₆, TD₇, TD₈, TD₉ and TD₁₀, respectively. Test day milk yields (TDMY) peaked at 10.02 kg/day during the fourth test day (TD4). Significant effects of calving period and season on several traits were noted to underscoring their importance in management practices. Heritability estimates for production traits varied, with FLMY showing the highest at 0.27, while test day milk records ranged from 0.04 (TD10) to 0.24 (TD2). Strong genetic correlations were found between FLMY, FLMY-300, TD4 and other traits, although negative correlations with AFC and dry period (FDP) were observed. For test-day milk records, genetic correlations ranged from 0.11 to 0.78, with the lowest correlation seen between the most distant test days. The phenotypic correlations for test-day yields varied from 0.12 to 0.82. The findings suggest that early test day records can effectively predict overall lactation performance, emphasizing the relevance of genetic parameters in developing breeding strategies for enhanced productivity in Hardhenu cattle.