Selection of cattle adapted for sustainable use of extensive rugged rangelands: Part 2 - What we can learn from the genotype.
Milt Thomas
Gonzalo Rincon
Juan Medrano
Derek Bailey
Publication Year

Genomic information and GPS collar measurements were used to examine cattle grazing distribution in extensive rangelands. This is the first study to conduct genotype to phenotype association studies of difficult to measure quantitative production traits that are important for rangeland sustainability. DNA was obtained from 87 beef cows that were tracked in mountainous and/or extensive rangeland pastures. The DNA was used for high density genotyping (BovineSNPHD; ~800,000 genotypes/cow) and the GPS data were used to characterize use of rough terrain and areas far from water using indices based on the normalized averages of slope use, elevation use, and distance to water. A chromosome region associated with these traits is known as quantitative trait loci (QTL) and the significance is determined by the statistical association of genotypes with phenotype effects (log10 p-value > 5). Significant QTL regions were detected on chromosomes 17 and 29 for slope and elevation. When these variables were combined with distance to water, QTL were detected on 11 chromosomes and a structural copy number variant QTL was detected on chromosome 8. A QTL region can span many base-pairs on a chromosome and encompass numerous genes. However, QTL analyses are a useful entry-point for identifying functional loci and potential genetic markers to help understand the genetic and physiological basis of cattle grazing distribution and to develop marker-based genetic selection procedures.

Additional Information
Milt Thomas1, Gonzalo Rincon3, Juan Medrano3, Derek Bailey2 --- 1Colorado State University, Fort Collins, CO, USA, 2New Mexico State University, Las Cruces, NM, USA, 3University of California, Davis, CA, USA