Location: Livestock Bio-Systems
2021 Annual Report
Accomplishments
1. Heifers developed on native range have better ovarian function than heifers developed in a dry lot. Nutritional status during the first year of life influences the development of the ovary in beef heifers. ARS researchers at Clay Center, Nebraska, developed feeding methods that increase the number of eggs in the ovary. Research with collaborators at New Mexico State University demonstrated that these benefits are 30% greater for heifers developed in a dry lot than for heifers developed on native range. This method increases reproductive longevity for heifers developed in a dry lot but may not be necessary for heifers raised on native range. Understanding the benefits of native range on ovarian development will help improve methods for developing fertile replacement heifers. Cow-calf producers can use nutritional programming to improve reproductive longevity in their herd, resulting in decreased cost of developing replacement heifers and increased profitability for the enterprise.
2. Estradiol improves nutrient transport to the developing conceptus. Estradiol is a hormone produced by the ovary during the reproductive cycle that is critical for proper uterine function and maintenance of pregnancy. ARS researchers at Clay Center, Nebraska, in collaboration with South Dakota State University investigated how estradiol influences uterine function during pregnancy in beef cows. Gene networks associated with nutrient transport were the primary targets for regulation by estradiol. Activation of these networks was associated with greater likelihood of maintaining pregnancy. Managing cows to ensure that they have initiated reproductive cycles prior to the breeding season will improve conception, leading to increased profit of $300 to $600 per pregnant cow for cow-calf producers.
3. Applying genomic markers to improve carcass traits does not negatively impact reproductive performance in replacement heifers. Selection for production traits in beef cattle can have unintended negative impact on reproductive function in the cow herd. ARS researchers at Clay Center, Nebraska, reported that genetic markers that associated with tenderness in beef steers also associated with a delayed calving date in heifers. To validate this detrimental effect on reproduction, ARS researchers at Clay Center, Nebraska, used data from steers to generate a breeding value for tenderness based on genetic markers. When used in heifers, the breeding value did not antagonize reproductive function. Cow-calf producers can apply these genetic markers to improve tenderness in steers without concern for unintended negative impact on reproductive function in replacement heifers.
Review Publications
Caton, J.S., Crouse, M.S., McLean, K.J., Dahlen, C.R., Ward, A.K., Cushman, R.A., Grazul-Bilska, A.T., Neville, B.W., Borowicz, P.P., Reynolds, L.P. 2020. Maternal periconceptual nutrition, early pregnancy, and developmental outcomes in beef cattle. Journal of Animal Science. 98(12):1-16. https://doi.org/10.1093/jas/skaa358.
Afedi, P.A., Larimore, E.L., Cushman, R.A., Raynie, D., Perry, G.A. 2021. iTRAQ-based proteomic analysis of bovine pre-ovulatory plasma and follicular fluid. Domestic Animal Endocrinology. 76:106606. https://doi.org/10.1016/j.domaniend.2021.106606.
Cunha, F., Cushman, R.A., Santa Cruz, R., de Nava, G., Vinoles, C. 2020. Antral follicular count has limited impact in the selection of more fertile beef heifers. Livestock Science. 241:104230. https://doi.org/10.1016/j.livsci.2020.104230.
Freetly, H.C., Cushman, R.A., Bennett, G.L. 2021. Production performance of cows raised with different postweaning growth patterns. Translational Animal Science. 5(3):1-7. https://doi.org/10.1093/tas/txab031.
Juengel, J.L., Cushman, R.A., Dupont, J., Fabre, S., Lea, R.G., Martin, G.B., Mossa, F., Pitman, J.L., Price, C.A., Smith, P. 2021. The ovarian follicle of ruminants: the path from conceptus to adult. Reproduction, Fertility and Development. Article RD21086. https://doi.org/10.1071/RD21086.
King, D.A., Shackelford, S.D., Cushman, R.A., Wheeler, T.L. 2021. Extended aging and marbling class effects on color stability of beef Longissimus lumborum, Gluteus medius, and Biceps femoris steaks. Meat and Muscle Biology. 5(1):1-14. https://doi.org/10.22175/mmb.11139.
Diniz, W.J., Crouse, M.S., Cushman, R.A., McLean, K.J., Caton, J.S., Dahlen, C.R., Reynolds, L.P., Ward, A.K. 2021. Cerebrum, liver, and muscle regulatory networks uncover maternal nutrition effects in developmental programming of beef cattle during early pregnancy. Scientific Reports. 11. Article 2771. https://doi.org/10.1038/s41598-021-82156-w.
Bennett, G.L., Keele, J.W., Kuehn, L.A., Snelling, W.M., Dickey, A.M., Light, D.E., Cushman, R.A., McDaneld, T.G. 2021. Using genomics to measure phenomics: Repeatability of bull prolificacy in multiple-bull pastures. Agriculture. 11(7). Article 603. https://doi.org/10.3390/agriculture11070603.
Hales, K.E., Tait Jr, R.G., Lindholm-Perry, A.K., Cushman, R.A., Freetly, H.C., Brown-Brandl, T.M., Bennett, G.L. 2020. Effects of the F94L Limousin associated myostatin gene marker on metabolic index in growing beef heifers. Applied Animal Science. 36(6):851-856. https://doi.org/10.15232/aas.2020-02046.
Northrop-Albrecht, E.J., Rich, J.J., Cushman, R.A., Yao, R., Ge, X., Perry, G.A. 2021. Influence of estradiol on bovine trophectoderm and uterine gene transcripts around maternal recognition of pregnancy. Biology of Reproduction. 105(2):381-392. Article ioab091. https://doi.org/10.1093/biolre/ioab091.
