Location: Livestock and Range Research Laboratory
2022 Annual Report
Accomplishments
1. Prediction accuracy of inbreeding depression improved. When genetically related animals are bred to one another, it is called inbreeding. Inbreeding depression refers to a decrease in performance of an animal. Decreased performance of some traits, like growth and fertility, can be costly to producers. The greater the level of inbreeding generally means the greater the decrease in performance. This research allows scientists to predict the effect of inbreeding on animal performance. New technology has allowed closer evaluation of the genes involved with inbreeding. Cattle that are more closely related have genes that are more similar. This similarity is referred to homozygosity. Runs of homozygosity can be used to determine the degree of inbreeding. Making this comparison at the chromosome level was better than at the whole animal level. This greatly increased the ability to predict the decrease in calf performance. The study was published in the journal, Animals.
2. Breed makeup of composite livestock are not stable and are influenced by management and environment. Composite breeds are commonly used in the U.S. beef industry. They provide producers with benefits such as breed complementarity and heterosis. Composite cattle genomes are not well characterized. In this study, genomic information was used to evaluate the genetic content of a three-breed composite (50% Red Angus, 25% Charolais, 25% Tarentaise) formed in the 1980s. Research was conducted from cattle in a cool, semi-arid environment. The proportion of Tarentaise in this composite increased to 57% while Charolais decreased to 5%, and Red Angus decreased to 38%. It appears that new genome segments formed around the sixth generation. These changes show that original breed proportions are not stable over generations and that environment and management affect the proportions. The increase in Tarentaise proportion suggests useful attributes to the composite in a cool semi-arid environment. The study was published in the Journal of Animal Science.
3. Replacement heifer nutrition is critical for embryo development. Almost half of the reproductive loss in cattle comes from early embryo death. Most of these embryos die between 8 and 16 days after fertilization. Replacement heifers are virgin cows that are developed for herd replacements. After weaning, many heifers are raised in a pen and provided feed. Other heifers are raised on pasture until breeding or raised on pasture until breeding at about 15 months of age. In some years, there is less forage available either before or after breeding. ARS researchers at Miles City, Montana, are studying effects of heifer nutrition before and after breeding on early embryo development. When less energy is fed to heifers for 30 days before breeding, hormone levels are reduced. Embryo development is also slower in heifers fed less energy before breeding. When less energy is fed for 7 days after breeding, embryo quality is reduced. Lower quality embryos and embryos that grow slower are less likely to result in pregnancy success. Producers should ensure heifers are fed sufficient energy before and after breeding to improve pregnancy rates. Higher pregnancy rates generally lead to greater profit.
4. Declining nitrogen availability in land ecosystems. Global supplies of nitrogen have more than doubled in the last century mainly due to industry and farming activities. Recent studies show nitrogen has decreased in many areas of the world. ARS researchers in Miles City, Montana, along with scientists in the United States and Europe have examined the causes of decreased nitrogen availability. Nitrogen inputs are not evenly distributed around the world. In many locations, increases in carbon dioxide and warmer temperatures are increasing plant demand for nitrogen. This increased nitrogen use by plants decreases its supply. In areas where nitrogen levels have decreased, plant growth can also be decreased due to lower nitrogen content. These decreases affect both the amount and quality of forage for livestock, wildlife, and insects. Several measures could be used to decrease these declines in nitrogen. Reducing carbon dioxide emissions would lessen the demand for nitrogen by plants. Nitrogen could also be better managed in areas that have experienced nitrogen declines. Strategic feeding of supplements may be required to maintain livestock production in areas where nitrogen is declining. In general, monitoring nitrogen conditions to inform management decisions should be adopted.
Review Publications
Pilon, B., Hinterneder, K., Hay, E.A., Fragomeni, B. 2021. Inbreeding calculated with runs of homozygosity suggests chromosome-specific inbreeding depression regions in Line 1 Hereford. Animals. 11(11). Article 3105. https://doi.org/10.3390/ani11113105.
Rinella, M.J., Bellows, S.E., Geary, T.W., Waterman, R.C., Vermeire, L.T., Van Emon, M.L., Cook, L.A., Reinhart, K.O. 2022. Early calving benefits livestock production under winter and spring warming. Rangeland Ecology and Management. 81:63-68. https://doi.org/10.1016/j.rama.2022.01.003.
Williams, A.R., Vermeire, L.T., Waterman, R.C., Marlow, C.B. 2022. Grazing and defoliation timing effects in Great Plains ponderosa pine woodland following a large summer wildfire. Forest Ecology and Management. 520. Article 120398. https://doi.org/10.1016/j.foreco.2022.120398.
Hay, E.A., Toghiani, S., Roberts, A.J., Paim, T., Kuehn, L.A., Blackburn, H.D. 2022. Genetic architecture of a composite beef cattle population. Journal of Animal Science. 2022. Article 230. https://doi.org/10.1093/jas/skac230.
McLean, M.K., Geary, T.W., Zezeski, A.L., Smith, M.F., Spencer, T.E., Pohler, K.G., Reese, S.T., Perry, G.A. 2022. Impact of preovulatory estradiol concentrations on subsequent luteal function in beef cattle. Systems Biology in Reproductive Medicine. 68(4):286-297. https://doi.org/10.1080/19396368.2022.2038717.
Rich, B., Thomas, D.B., Longnecker, M., Tolleson, D., Angerer, J.P., Perez de Leon, A.A., Teel, P. 2022. Bovine fecal chemistry changes with progression of Southern Cattle Tick, Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) infestation. Veterinary Parasitology. https://doi.org/10.1016/j.vetpar.2022.109679.
Rowell, J.E., Blake, J.E., Roth, K., Sutton, C., Sachse, C., Cupp, A.S., Geary, T.W., Zezeski, A.L., Alexander, B.M., Ziegler, R.L., Shipka, M.P. 2022. Medroxyprogesterone acetate in reindeer bulls: testes histology, cfos activity in the brain, breeding success and semen quality. Journal of Animal Sciences. 100(6):1-11. https://doi.org/10.1093/jas/skac106.
Mason, R., Elmore, A., Fulweiler, R.W., Groffman, P., Craine, J., Lany, N., Jonard, M., Ollinger, S., Angerer, J.P., Read, Q., Reich, P.B., Templer, P.H. 2022. Evidence, causes, and consequences of a global decline in ecosystem nitrogen availability in terrestrial ecosystems. Science. 376(6590). https://doi.org/10.1126/science.abh3767.