A REVIEW OF THE FEEDING-HEALTH-PRODUCTION COMPLEX IN A DAIRY-HERD

Diseases may be an important link in the relationship between feeding and production in a dairy herd. The low frequency of relevant disorder s calls for studies on survey data on a large population. However, thi s approach suffers from lack of detailed herd feeding data and consequ ently only few have studied feeding as a risk factor for disease. Ther efore, we reviewed information from various studies to integrate what is known of the feeding-health-production complex in a dairy herd. The need for putting together information from different sources, the her d effects, and the fact that the effect of one factor cannot be kept c onstant for investigation in a real-life dynamic herd call for a conce ptual model as a framework for the review. The complexity is minimized to allow the representation of important elements. Within-cow relatio nships (such as feeding-disease relationships, disease interrelationsh ips, and disease-production relationships) are reviewed specifically f or: ketosis, milk fever, displaced abomasum, acidosis, sole ulcers and laminitis, and bloat. The major feeding management factors involved a re concentrate feeding (level and how it is provided) and overconditio ned cows. Disease interrelationships are important. Generalization of production loss from diseases is complicated due to the variety of est imates and measures used. (C) 1998 Elsevier Science B.V.