Recording of production diseases in cattle and possibilities for genetic improvements: A review

A frequent occurrence of production diseases can restrict the possibilities of having an efficient milk production considerably. Management and environmental corrections are the primary changes that should be made in order to reduce disease incidence. Breeding activity can also be a fruitful area to consider, but it requires the efficient recording of diseases. Procedures for recording diseases may be categorised as either direct or indirect, and advantages and disadvantages of both types are discussed. Some of the most important production diseases in cattle have been shown to be influenced by inherited factors. Heritability estimates for diseases recorded directly through clinical registrations are, however, generally low, usually below 5%, while heritabilities of diseases recorded by indirect measurements have proved somewhat higher. Although the heritabilities are low, the genetic variability has been shown to be reasonably high, suggesting that a significant genetic improvement of the disease resistance is achievable if proper procedures are applied. However, the inclusion of disease resistance into the overall breeding objective necessitates a thorough investigation of its value, in economic or other terms, relative to production traits. The situation is further complicated by results showing that a genetic antagonism probably exists between production traits and disease resistance.