U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska


Date of this Version


Document Type



Published in Beef Research Program Progress Report (1993) No. 4 (Part 1): 43-47


Based on requirements for assistance at first parturition as two-year-olds, experimental results document the importance of dystocia in major breeds of Bos taurus cattle. In addition to the greater labor and managerial requirements associated with dystocia (calving difficulty), experimental results show that dystocia results in reduced perinatal calf survival and reduced conception rate in females in the subsequent breeding season when dystocia is experienced. There is not agreement on the value of pelvic measures as a predictor of dystocia at first parturition. Information is limited on the genetic relationship between pelvic measures and other factors that may be genetically associated with dystocia. Selection criteria and procedures that have high predictive value for dystocia and can be evaluated prior to an age of one year when selection decisions are normally made are needed to optimally combine information on a series of bioeconomic traits to increase selection response for reducing dystocia without loss in postnatal growth rate. Because most of the selection opportunity in cattle is among males, selection criteria among males must have high predictive value in their female progeny. The purpose of this study was to provide estimates of genetic and phenotypic parameters on a series of bioeconomic traits evaluated at, or prior to, one year of age as a basis for developing selection criteria and procedures that may result in reduced dystocia while maintaining rate of postnatal gain.