Date of this Version
Results from the Germplasm Evaluation Program (GPE) at the Roman L. Hruska U. S. Meat Animal Research Center (MARC) have shown that significant differences exist among cows representing breeds of diverse biological types In such production traits as 200-day weaning wt per cow in the breeding herd. Production of Bos indicus F1 cross cows (Brahman and Sahiwal sired crosses out of Hereford and Angus dams) was equalled only by F1 cross cows sired by large size dual purpose breeds (Brown Swiss, Gelbvleh, Simmental, Holstein and Maine Anjou crosses out of Hereford and Angus dams) excelling in milk production and genetic potential for growth. Indications are that the advantages of Bos indicus crosses are associated with greater heterosis found in Bos indicus x Bos taurus crosses than is found in crosses of two Bos taurus breeds. In the GPE program, F1 cross cows by diverse sire breeds were compared when they were raising terminal three-breed cross calves by bulls of an unrelated Bos taurus breed (e.g., Simmental or Brown Swiss). Thus, progeny of Bos indicus sired F1 cross cows were 25% Bos indicus and 75% Bos taurus compared to progeny of 100% Bos taurus inheritance for all other F1 cross cows. Matings were made to determine the optimum proportion of Bos indicus inheritance in a temperate environment. Results for mortality and cold tolerance of calves containing increasing proportions of Bos indicus (0, 25, 50 and 75% Brahman or Sahiwal) relative to Bos taurus (100, 75, 50 and 25% Angus, Hereford or Pinzgauer) inheritance are presented in this report.