Genetic evaluation of calving difficulty in cattle: A review

Abstract

Advantages and drawbacks of different approaches of genetic evaluation of calving difficulty are described and discussed in the review. Calving difficulty is a complex trait, which affects the economics of cattle breeders. The main factors affecting calving difficulty include calf size, pelvic measures of the cow and, more importantly, their compatibility, breed, parity of the calving, sex of the calf, gestation length and the season of the calving. Scoring scales of calving difficulty differing in the number and description of the categories are applied across the countries. Among the various statistical approaches, preference is given to threshold and linear models for genetic evaluation of calving difficulty. It seems that linear models are more suitable for the use of field data. An improvement of predictions can be obviously achieved by the application of correlated traits.