Genetic parameters of production, feed intake, body weight, body composition, and udder health in lactating dairy cows

摘要: Records on milk yield, body weight, feed intake, SCC, mastitis incidence, and indicators of composition were analysed both as repeated measures within lactations aggregated lactation measures. The data comprised 603 293 dairy cows an experimental farm in Denmark. Most genetic parameters agreement with similar results from the literature. Minimum weight is reached earlier than peak yield much before intake. Genetic selection for higher production will lead to lower gains during therefore that are less well prepared meet energy requirements subsequent lactation. There positive correlations between mobilisation reserves SCC indicating increased leads metabolic stress a change immune system. Single trait increases thereby frequency. Cows large fat depots had production. However, leaving cow next This study showed variation variables attempting describe shape curves Therefore, encouraged continuation recording these variables, physiological understand fundamental biological complex balance lactating needed. may be using random regression models order forward mechanisms records early late