375 Genomic Approaches for Feed Efficiency in Sheep

Abstract United States seedstock sheep producers have selected for higher weaning and post-weaning weights using estimated breeding values approximately forty years. Despite this, little work has investigated if the increased performance inadvertently resulted in feed intakes, increasing total costs producer. Eighty range-breed ewe lambs (forty Targhee Rambouillet) were enrolled a residual intake (RFI) trial shortly after at four months of age. Feed was recorded utilizing GrowsafeTM feeding system modified sheep. Following two-week adaption period, intakes daily forty-two days. Body collected beginning, end, weekly throughout period. Residual calculated mid-trial body measurements. Six ewes removed from due to failure adapt system. Linear regressions utilized determine association between weight RFI weight. As expected, there significant relationship (p< 0.05) value during trial. No statistically identified, indicating selection not decreased efficiency growth phase. Additional measures will be on these same later life stage represent maintenance phase production as opposed In addition, genetic rumen microbial analysis is ongoing. Together approaches aid construction framework eventual genomic U.S. range