Year: 2017 | Month: February | Volume 7 | Issue 1
Genetic and Non-Genetic Parameters of First Lactation Milk Yield, Composition and Energy Traits in Karan-Fries Cat
Abstract:
Records of 1471 Karan-Fries cows from 102 sires with five or more daughters per sire during the period 1989-2013 were used to study genetic and non-genetic parameters for First lactation 305-days or less milk yield (FL305MY- kg), First lactation 305 days or less wet average (FL305WA- kg), Average test day milk yield (ATDMY- kg), Average test day fat percentage (ATDFP-%), Average test day fat yield (ATDFY-g), Fat based energy per kg (FBE/kg-cal) and Fat based energy per first lactation 305 days or less milk yield (FBE/FL305MY–kcal). The non-genetic parameters were analysed by fixed linear model. Heritability and phenotypic/genetic correlations were estimated by paternal half sib correlation method and sire variance and covariance, respectively. Period of calving was significant for all the traits. Season had significant effect on all the traits except ATDFP and FBE. Age group was significant for ATDFP only. The FBE/FL305MY had positive and significant (P<0.01) genetic and phenotypic correlations with FL305MY, FL305WA, ATDMY and ATDFY. The positive phenotypic correlation of ATDFP and FBE/kg with composition and energy traits revealed selection for an increased fat percentage will improve the concentrations of other constituents in milk. Higher estimates of heritability, significant genetic and phenotypic correlation between FL305MY and FBE/FL305MY revealed that any of the two traits can be used for genetic evaluation of Karan-Fries bulls when genetic improvement is sought.
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