Location: Range Sheep Production Efficiency Research
2020 Annual Report
Accomplishments
1. Facilitating genetic improvement of the Polypay sheep breed. Profitable producers strive for genetic improvement in their livestock. One way to achieve this is through use of estimated breeding values (EBV), which indicates an individual’s genetic potential for a trait. The accuracy of EBV is dependent upon the number of production records from the individual of interest as well its relatives (offspring, siblings, parents, etc.). Further, confidence in comparing EBV across flocks is greatly enhanced if flocks have strong genetic connectedness (i.e., share ancestry). Unfortunately, such kinship data is often lacking in the sheep industry, resulting in EBV of subpar accuracy. In an extensive effort to improve the utility of EBV for the Polypay sheep breed, ARS researchers at Dubois, Idaho, collected, formatted, and uploaded 17,379 records to the National Sheep Improvement Program, which is the primary database used for calculating EBV for U.S. sheep. The large volume of records and genetic connectivity to other flocks will result in increased accuracy of EBV and improved confidence in comparing EBV across flocks for the Polypay breed, thus enabling producers to meet their genetic improvement goals sooner.
2. Mitigating the burden of rearing orphan lambs. The annual number of lambs born to a ewe (female sheep) greatly influences profitability of range sheep enterprises. In highly prolific flocks, some ewes may give birth to more lambs than they can successfully rear, which is the case for triplet-bearing, wool-type ewes managed in rangeland systems of the U.S. West. Often, producers are forced to orphan at birth and artificially rear (e.g., bottle feeding) extra lambs, which drastically erodes profitability. ARS scientists in Dubois, Idaho, have developed a solution that involves leaving triplet lambs with the birth ewe until the lambs are approximately 35 days of age, then immediately weaning one of the triplet lambs. This method reduces the burden of artificially rearing orphan lambs and thus, maintains profitability. Such management solutions are critical for producers to efficiently improve flock lambing rates without suffering from the economic and laborious burden of artificially rearing orphan lambs.
Review Publications
Sprinkle, J.E., Taylor, J.B., Clark, P., Hall, J.B., Strong, N.K., Roberts-Lew, M. 2019. Grazing behavior and production characteristics among cows differing in residual feed intake while grazing late season Idaho rangeland. Journal of Animal Science. 98(1):1-9. https://doi.org/10.1093/jas/skz371.
Henslee, D., Yelich, J., Taylor, J.B., Ellison, M. 2019. Avoidance of Phenylthiocarbamide in mature Targhee and Rambouillet rams. Translational Animal Science. 3(4):1194-1204. https://doi.org/10.1093/tas/txz125.
Murphy, T.W., Stewart, W.C., Smith, C.G., Taylor, J.B. 2018. Effects of late gestation shearing on body weight, feed intake, and plasma metabolite concentrations in Rambouillet ewes managed outdoors during winter. Animal. 13(3):600-605. https://doi.org/10.1017/S175173111800191X.
Page, C.M., Van Emon, M.L., Murphy, T.W., Larson, C.K., Berardinelli, J.G., McGregor, I.R., Taylor, J.B., Stewart, W.C. 2019. Effects of zinc source and dietary concentration on serum zinc concentrations, growth performance, wool traits, and reproductive characteristics in developing rams. Animal. 14(3):520-528. https://doi.org/10.1017/S1751731119002180.
