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Genetic evaluation of Alpine goats using test day milk yield

This paper is available in a repository.
This paper is available in a repository.

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Abstract

Data consisting of 26,389 individual test day milk yield from 825 lactations of 356 Parda Alpina goats, recorded from 1997 to 2004, were used to estimate genetic parameters and to predict breeding values for test day (PLDC) and accumulated (PAC) milk yields. The model for PLDC included the fixed effects of contemporary group (year-month of test), age of dam at kidding as covariate, and additive genetic, permanent environment and residual random effects. The model for PAC included the same random effects used for PLDC and the fixed effects of contemporary group (year-month of kidding) and the covariates age of dam at kidding and lactation length. Larger heritability estimates for milk yield in the intermediary test days indicate possibility of selection response. Rank correlation between breeding values for milk yield up to 305 days and intermediary PLDC were larger than those on early and late lactation. Despite the high rank correlation, changes in ranking of bucks for milk yield up to 305 days were observed when selection was based on PLDC at 90 days. Selection based on PLDC and PAC in middle lactation may be used as a selection criterion in substitution for milk yield up to 305 days.