Results of eight years of artificial insemination in a purebred Angus herd

Abstract

Statement of Problem: The purpose of this study was to determine, from records of Kermac Angus Ranch, Poteau, Oklahoma, factors that influence results in a beef cow herd artificially inseminated. The results of this study will be used to help cow herd owners of LeFlore County alter their management practices for greater profits.

Methods and Procedure: Records of 783 conceptions resulting from artificial insemination at Kermac Angus Ranch were studied to determine how breeding efficiency varied between groups of cows, by seasons of the year, by years, and by age of cows. In addition, a study was made of the influence of delaying rebreeding and a study of how a heifer's first conception could serve as an indication of her future efficiency as a breeder.

Findings and Conclusions: The 783 conceptions required an average of 2.14 services per conception and 48.43 percent of these conceptions were conceptions to first service. There was rapid improvement in services required per conception during the first four years of the study and very little improvement in the last half of the study. Rate of conception to first service showed only slight improvement after 1960. Breeding efficiency of cows in this study steadily improved through five years of age. Percentage of cows settling to first service increased to five years of age. Best results were obtained when breeding was started during the first quarter of the year. There was a steady improvement in breeding efficiency of cows born during the different years of the study. Delaying rebreeding until 90 days or more postpartum seemed to improve breeding efficiency. Heifers requiring four or more services for their first conception were poorer breeders later than heifers requiring less than four services for their first conception.