Location: Range and Livestock ResearchTitle: Influence of Miles City Line 1 on the United States Hereford Population) Author
|Leesburg, Vicki - Reisenauer|
Submitted to: Journal of Animal Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/12/2014
Publication Date: 6/24/2014
Publication URL: http://handle.nal.usda.gov/10113/59333
Citation: Leesburg, V.L., MacNeil, M.D., Neser, F.C. 2014. Influence of Miles City Line 1 on the United States Hereford Population. Journal of Animal Science. 92:2387-2394. Interpretive Summary: Line 1 Hereford cattle have served as study material for numerous research projects since the mid-1930's. Studying the use of Line 1 Hereford cattle provides insight into dissemination of these cattle to an industry where they have been used in livestock breeding operations for almost 70 years. The focus of this research was to evaluate the use and potential influence of Line 1 Hereford within the United States. The Line 1 Hereford has contributed genetically through distribution of its genetics through production sales; rarely would this type of influence from one herd be seen anywhere in the world. Culturally speaking, the Line 1 Hereford serves as a visual document of Fort Keogh's research history and impact. Through these results it is apparent the Line 1 Hereford serves as a visual document of Fort Keogh's research history and impact. Through these results, it is apparent the Line 1 Hereford cattle from Miles City, MT, have influenced Hereford cattle around the United States. The first evaluation of the relationship Line 1 had to other Herefords in the U.S. was in 1983 and the relationship with 64%. Our study evaluated the period from 1980 to 2008 and the rate at which the Line 1 increased in relationship to other Hereford cattle was 1.69 ± 0.07% per year. Leading to the present day relationship of Line 1 to Herefords in the U.S. at 79%. The greatest concentration of these cattle related to Line 1 can be found in the Great Plains and Eastern Corn Belt. But Herefords related to Line 1 were found in 48 of the 50 states. Finally, 240 Line 1 and 311 Hereford sires are representative of the Hereford breed in the US and were genotyped for 50K SNP. The probability that the sires from the US population were members of Line 1 was 0.20. These results document the far-reaching and profound impact of a long-term research program.
Technical Abstract: The goal of this research was to document the influence of Line 1 (L1) Hereford cattle developed by the United States Department of Agriculture at its research facility in Miles City, Montana, on the United States Hereford population. The L1 Hereford population originated in 1934 and has been thereafter maintained as a closed herd at that location. Dissemination of germplasm began in 1948. Pedigree data for approximately 14 million cattle recorded by the American Hereford Association (AHA) were used. A preliminary experiment was conducted to establish sample size necessary to estimate the pedigree relationship between Line 1 and the recorded Hereford population. Five random samples of 100, 400, 500, and 3000 calves were drawn from the sets of calves born in 1980, 1990, and 2000. Sampled calves were pseudo-mated to Line 1 sires from the decades 1968 to 1978, 1978 to 1988, and 1988 to 1998, respectively. Inbreeding coefficients were calculated for the resulting "offspring" and the relationship of each sampled animal to Line 1 was taken to be twice the maximum inbreeding coefficient for the set of Line 1 sires used in the pseudo-matings. Based on the results of this experiment, it was decided that a sample size of 400 animals per replicate was sufficient to estimate the relationship between Line 1 and the general Hereford population recorded by AHA. In a second analysis, five sets of 400 animals were drawn from the AHA herdbook for the years 1980-2008, pseuo-mated to Line 1 sires, and their relationship to L1 calculated as described above. Over the period, the number of animals recorded by AHA that were related to L1 increased by 1.69 ± 0.07% per year. The L1 Hereford population was ancestral to 79% of Hereford cattle recorded in 2006-2008. The greatest concentration of animals related to L1 was in the Great Plains and Eastern Corn Belt of the USA, but animals related to L1 were found in 48 states. In a third experiment, 240 L1 Hereford cattle and 311 sires representative of the Hereford breed in the U.S. were genotyped for 50K SNP. Resulting genotypes were used to assess the probability that the animals sampled from the U.S. population were members of L1. The average probability of membership was 0.20 and the regression of pedigree relationship on genomic probability of membership was 1.73 ± 0.11 (R = 0.65). These results document the far-reaching and profound impact of a long-term research program.