Genomic information and GPS tracking data were used to examine genetic influences on cattle grazing distribution. A total of 87 cows were tracked for 1 to 3 months in mountainous and/or extensive pastures at 5 ranches located in New Mexico, Arizona, and Montana. The Illumina Bovine SNPHD array, which evaluates approximately 770,000 genetic markers (i.e., single nucleotide polymorphisms; SNP) was used to genotype DNA from these cows. Tracking data were used to calculate terrain use indices based on normalized averages of slope use, elevation use, and distance travelled from water. A chromosome region associated with these traits is known as a quantitative trait locus (QTL). One genetic marker on chromosome 29 overlaid a gene that has been reported to be a factor in feeding behavior, appetite and locomotion. This locus accounted for 25% of the phenotypic variation in use of steep slopes and high elevations, while a QTL on chromosome 17 accounted for 21% of phenotypic variation. Additional QTL accounted for 5 and 10% of the variation in terrain use indices. Using results from the QTL analyses,  a smaller 50 SNP panel was developed and used to evaluate the 87 cows tracked previously and an additional 73 cows from 4 ranches. With the 50-SNP panel analyses, multiple genetic markers near or within the gene identified on chromosome 29 were associated with indices of terrain use and accounted for 10 to 18% of the phenotypic variation. In addition, a marker on chromosome 4 accounted for 26% of the variation. Other QTL on chromosomes 8, 12 and 17 accounted for 8 to 16% of the phenotypic variation in terrain use indices. The associations between terrain use indices and multiple genetic markers near candidate genes clearly shows that cattle grazing distribution is inherited.
Oral presentation and poster titles, abstracts, and authors from the Society for Range Management (SRM) Annual Meetings and Tradeshows, from 2013 forward.