Submitted to: Western Section of Animal Science Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/1/2002
Publication Date: 6/1/2002
Citation: Tseveenjav, .B., Maiwashe, .N., Golden, B.L., Blackburn, H.D. 2002. Predicted rate of inbreeding for a closed line of hereford cattle. Western Section of Animal Science Proceedings. 52:105-107. Interpretive Summary: Within-breed inbred lines of cattle can be used to provide insights about genetic diversity in subpopulations of a breed. This work quantifies the change in inbreeding levels for such an inbred line of Hereford cattle. It was found that inbreeding levels increased and decreased over the 60-year existence of the line. During this time period, 12 generations of cattle were generated. Across generations, the population had an average inbreeding level of 21.5%. The maximum inbreeding level for an individual animal was 57.8%. During the last three generations inbreeding decreased as cattle from outside the station, but of the same line, were introduced, therefore increasing the level of genetic variation.
Technical Abstract: The purpose of this study was to determine the rate of inbreeding for a closed line of Hereford cattle at San Juan Basin Research Center Colorado (SJBRC). This line (Prospector) is one of the inbred lines that was established in early '40s to examine the effects of intensive inbreeding and subsequent line crossing on various traits. A total of 994 pedigree records was used to calculate inbreeding coefficients using the Animal Breeders Tool Kit. Only inbreeding coefficients from individuals identified as Propsector line (n= 323) were used in further analysis. Forty-six percent of the individuals had a non-zero inbreeding coefficient with an average and maximum coefficent of 21.5% and 57.8%, respectively, The rate of inbreeding increased in the first three generations with the maximum reached at generation three, and it was due to use of same individuals in consecutive years. However, a sharp decline was observed in the next few generations, and there was a tendency to stablize around zero in the last generation. This result suggests that the rate of inbreeding was not constant through the generations. Therefore, minimization of the predicted rate of inbreeding in future generation is important for the maintenance of genetic variation.