Effects of milk fever, ketosis, and lameness on milk yield in dairy cows.

摘要: The effects of milk fever, ketosis, and lameness were studied using data from 23,416 Finnish Ayrshire cows that calved in 1993 followed for one lactation (i.e., until culling or the next calving). Monthly test day yields treated as repeated measurements within a cow mixed model analysis. Disease index variables created to relate timing disease measures milk. Statistical models each parity included fixed calving season, stage lactation, index. An autoregressive correlation structure was used association among measurements. yield contracting fever affected period 4 6 wk after calving; loss ranged 1.1 2.9 kg/d, depending on time elapsed diagnosis. Despite loss, with produced 1.7 kg more milk/d than did healthy cows. Milk started decline 2 before diagnosis ketosis continued varying it. daily greatest diagnosis, 3.0 5.3 parity. Cows higher most severely by ketosis; average total per 353.4 kg. Lameness also yield; diagnosed foot leg disorders varied between 1.5 2.8 kg/d during first