First-calving age and first-lactation milk production on Dutch dairy farms

摘要: Abstract Farmers attempting to reduce first-calving age (FCA) need understand which rearing management factors influence FCA and first-lactation milk production (FLP). Reduced might be associated with lower FLP. This study describes the association between herd FCA, FLP, several herd-level health variables FLP at cow level. It uses data from a 2010 survey of 100 Dutch dairy farms about general management, colostrum feeding, housing, cleanliness, healthcare, disease, breeding. also used available on 305-d both The associations median were determined using multivariate regression analysis. was minimum first insemination, feeding waste milk, amount given preweaning. vaccination status for bovine respiratory syncytial virus. (based 8,454 heifers) analyzed single-effect linear mixed model, where dependent variable either or relative (defined as difference heifer they belonged). Heifers having an 24 mo produced, average, 7,164 kg per 305 d, calving 1 mo earlier gave 143 kg less 305 d. When did not deviate heifers 7,272 kg From herd, produced 90 kg 305 d less, later 86 kg more. is that explained FCA. assumes raised within same farm have similar development because are similarly managed. Similar reflected by deviation heifer’s reflecting herd’s average. advantage it accounts between-farm differences in management. showed insemination without adjusting ensure sufficient lowers An economic optimum exists costs, and, consequence, decisions regard young stock should made care.