GENETIC CORRELATIONS OF DAYS OPEN WITH MILK YIELD AND METABOLIC WEIGHT IN HOLSTEIN AND BROWN SWISS COWS Correlaciones genéticas de días abiertos con producción de leche y peso metabólico en vacas Holstein y Pardo Suizo
Year: 2015
Type: article
Abstract: The aim of the present study was to estimate (co)variance components and genetic correlations of days open with milk yield per lactation, lactation length and metabolic weight in Holstein and Brown Swiss cows under subtropical conditions of Mexico. Cows were kept in an intensive rotational grazing system in which the principal feed was Star grass (Cynodon plectostachyus). Cows were milked twice daily, by machine. Analyses of data were made applying a series of bivariate animal models in the MTDFREML program. Models for days open, milk yield per lactation and metabolic weight included breed of cow, calving year, calving season and lactation number as fixed environmental effects, and animal direct genetic, cows permanent environmental, and residual as random effects. For lactation length the model included the same fixed and random effects, except cows permanent environmental effect. The estimates of genetic correlations of days open with milk yield per lactation and metabolic weight were moderate and positive (0.45 and 0.33, respectively), suggesting that genes that control milk yield per lactation and metabolic weight also control days open. Estimates of phenotypic and permanent environmental correlations were smaller than estimates of genetic correlations. Results of the present study evidence that poor genetic potential for reproductive performance is associated with high genetic potential for milk production and metabolic weight.
Language: English
Subfield: Genetics
Domain: Life Sciences
SDG: Zero hunger
Open Access status: green
OpenAlex ID: W1873561729