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 disorders calls for studies on survey data on a large population. However, this approach suffers from lack of detailed herd feeding data and consequently only few have studied feeding as a risk factor for disease. Therefore, 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 herd effects, and the fact that the effect of one factor cannot be kept constant for investigation in a real-life dynamic herd call for a conceptual model as a framework for the review. The complexity is minimized to allow the representation of important elements. Within-cow relationships (such as feeding-disease relationships, disease interrelationships, and disease-production relationships) are reviewed specifically for: ketosis, milk fever, displaced abomasum, acidosis, sole ulcers and laminitis, and bloat. The major feeding management factors involved are concentrate feeding (level and how it is provided) and overconditioned cows. Disease interrelationships are important. Generalization of production loss from diseases is complicated due to the variety of estimates and measures used.