[Correlations between the first lactation and the lifetime performance traits in Holstein-Friesian cows]
1997
Markovic, M. (Biotechnical Institute, Podgorica (Yugoslavia)) | Vidovic, V. | Adzic, N. | Veljic, M. | Markovic, B. | Ljumovic, M.
Data on 2834 lactation records of 689 cows from two farms, daughters of 39 sires, were analysed for relationship of the first lactation traits with traits of total lifetime performance using REML methodology and a linear mixed model. Effects of farm, year, number of lactation, genotype and age at the first calving were considered to be fixed, and sires were considered to be random. Each cow had at least three complete lactations. Phenotypic means of the first lactation and total lifetime milk yield were relatively high, and ranged considerably. The estimates of heritabilities of the first lactation yield traits were low, but heritabilities for total lifetime performance traits were within the range of heritabilities reported in the cited literature. All genetic and phenotypic correlations were positive, except correlations of fat percentage taits. Genetically, the first lactation milk yield was highly correlated with most measures of lifetime performance, from 0.63 to 0.97, except lifetime fat percentage (0.11). Given high positive genetic correlations, selection on the first lactation milk yield will improve all measures of lifetime performance.
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Эту запись предоставил Unassigned data from Yugoslavia
