Location: Livestock and Range Research Laboratory2022 Annual Report
Objective 1: Evaluate effects of heifer development and winter supplementation protocols that differ in level and type of harvested feed inputs on the sustainability of beef production systems, including annual reproductive success, lifetime productivity, and progeny performance. Component 1: Problem Statement 1A, 1B Objective 2: Establish postweaning heifer development protocols that provide opportunities for improved fertility and differential forage utilization. Component 1: Problem Statement 1A, 1B Objective 3: Integration of phenomics and genomics data to dissect the genetic basis of reproductive and growth traits in beef cattle. Component 1: Problem Statement 1A, 1B Component 2: Problem Statement 2A, 2B, 2D Objective 4: Study the effect of environment, management and genetic interaction on range beef cattle production. Component 1: Problem Statement 1A, 1B Component 2: Problem Statement 2B, 2D We have proposed a series of experiments that will contribute to the alleviation of rate limiting factors that compromise beef production efficiency by: 1) Collectively increasing knowledge of the phenotypic and genetic interplay between nutrition and lifetime reproductive efficiency (Objectives 1, 2, 3 and 4) thus facilitating the economic optimization of feed level and identification of germplasm that is of less risk of reproductive failure when feed level is reduced; 2) Developing strategies that will provide producers management approaches to better utilize forage and better cope with yearly environmental variation (Objective 1, 2, and 4); 3) Further identifying phenotypic and genomic factors controlling fertility in bulls and establishment and maintenance of pregnancy in females thus leading to targets for managerial interventions that increase pregnancy rate, decrease replacement rate and reduce cost associated with producing replacement females (Objective 1, 3, and 4); 4) Prioritizing weighting of phenotypic and genotypic traits influencing production at the time selection decisions occur (typically at approximately one year of age) targeting lifetime performance (Objectives 1, 2, 3, and 4) thus facilitating selection of breeding stock for efficient low-cost production. Work needed to accomplish our objectives is multi-disciplinary and contributions from more than one scientist are expected in order to bring each objective to fruition.
Feed consumption and replacement of cows, culled for reproductive failure, are two primary determinants of beef production efficiency. Our overarching goal is to develop strategies and technologies to alleviate these limitations. Sufficient nutrient intake resulting in adequate body energy stores are believed essential for reproduction. Thus, producers are challenged to match nutritional environment, which is subject to seasonal and annual variation, and various genotypes to obtain sustainable reproduction and retention rates. Our approach is, of necessity, long-term and multi-disciplinary, involving both basic and applied aspects of genetics, nutrition, and physiology in a semi-arid grazing production system. This proposal brings to fruition ongoing research and establishes investigations of genetic by environmental interactions and physiological mechanisms limiting reproductive success. Four distinct cattle populations (an intercross of Charolaise (25%), Red Angus (50%) and Tarentaise (25%), Line 1 Hereford, purebred Angus, and Hereford-Angus herd) will be used to facilitate assessment of genetic factors affecting fitness (hybrid vigor). Distinct nutritional environments differing in provision of harvested or grazed forage will be tested to challenge the nutrition-reproduction interface to reveal roles of genetic, physiological, and management factors influencing feed utilization and lifetime productivity. Identification of genetic, nutritional, and physiological mechanisms that limit or contribute to beef production efficiency will facilitate early in life selection and management of replacement animals most fit for particular production environments. This research will result in the establishment of evidence based beef female development and management protocols that provide producers options for dealing with annual environmental variations.
This is the final report for this project which expires in October 2022. The replacement project, 3030-31000-019-00D, “Identifying and Mitigating Factors that Limit Beef Production Efficiency” for this project begins in mid-October. Objective 1, Sub-objective 1A: Progress on our project included data analysis on retention and progeny data collected over a 9-year period for manuscript preparation within the Red Angus/Charolais/Tarentaise-composite cow herd. No retention and performance data were collected for 2022 because of drought conditions and herd reductions. Objective 2, Sub-objective 2A: Data have been organized for analyses and publication of a manuscript on nutritional and grazing management flexibility under changing environmental conditions. Retirements of two key scientists have delayed this publication. Objective 2, Sub-objective 2B: Data have been collected and are being analyzed to prepare a manuscript. Objective 2, Sub-objective 2C: Manuscript has been submitted comparing precision of two methods for estimating activity of rangeland heifers monitored with collars equipped with GPS and motion sensors: One method used movement velocity thresholds from GPS data and the second method was based on distance thresholds from GPS data and 2-axis accelerometer data. Both methods yielded similar estimates for time spent resting and grazing. Differences between the two methods were found in estimated time spent traveling. Both methods presented an acceptable degree of concordance. The GPS method appeared to be a reliable means of estimating cattle activities within certain limits. GPS data revealed that heifers developed in the feedlot traveled farther and covered larger areas of the pasture during the first few days of spring grazing than heifers developed on range and provided a protein supplement. Objective 2, Sub-objective 2D: Post-weaning performance data collection for calves was completed and is being analyzed to compare developmental nutrition management differences on progeny performance. No additional progeny data were collected this past year because of drought conditions and herd reductions. Objective 3, Sub-objective 3A: A genome-wide association study of longevity was conducted, and results revealed several quantitative trait loci associated with longevity. Further, a study on genomic prediction of fertility traits was conducted and results indicated that inclusion of genomic information increased the genetic prediction of pregnancy status by 26 to 29%. Furthermore, a study dissecting genetic composition of the composite beef cattle population at Fort Keogh was conducted and showed a change in the progenitor breed proportions. The study also revealed several selection signatures on the genome of the composite. The study was published in the journal of Animal Science. Objective 3, Sub-objective 3B: Bull fertility phenotypes and semen were collected in 2018 and 2019 from yearling bulls within the Line 1 Hereford-Angus heterosis project and evaluated using standard and 4 novel flow-cytometry measures of fertility. Samples were then frozen and further evaluations post-thaw have been conducted. We have not yet completed analyses of the post-thaw evaluation of these semen samples. An additional fertility evaluation has been performed on frozen/thawed semen of bulls with known high and low field fertility and manuscripts are in preparation. Preliminary analyses revealed that some of our measures may be predictive of field fertility but will require sampling a larger population. More detailed evaluation of these sperm biomarkers may provide enhanced scrutiny of bull fertility and improve developmental management for bull fertility. Objective 3, Sub-objective 3C: As part of the Grand Challenge collaboration with ARS researchers in Miles City, Montana, Clay Center, Nebraska, Fort Collins, Colorado, and El Reno, Oklahoma, growth and carcass data were collected from calves finished in 2020 and 2021. Because of drought and herd reductions, calves from the Grand Challenge were not received at Fort Keogh during the 2021-2022 calendar year. Data are currently being analyzed for meeting presentations and manuscript preparation. Objective 4, Sub-objective 4A: Final growth and reproduction data on heterosis animals were collected. The phenotypic data are being summarized. Genomic information will be used to detect heterotic variants (dominance effects) and evaluate the effect of heterosis on economically important traits. Analysis and characterization of inbreeding in Line 1 Hereford using genomic data has been completed. The results showed that inbreeding is not evenly distributed across the genome and that chromosomal level inbreeding affect phenotypes differently. Objective 4, Sub-objective 4B: Pregnancy success is greater and embryonic mortality is less among cows that are induced to ovulate a large (physiologically mature) follicle compared to a small (physiologically less mature) follicle. Research indicates that physiologically immature oocytes lack the transcripts, and thus enzymes available within specific metabolic pathways, to provide adequate energy to support embryo development and pregnancy success. Objective 4, Sub-objective 4C: Cows that ovulate a larger follicle also experience greater circulating concentrations of preovulatory estradiol and progesterone during early pregnancy. Inadequate preovulatory estradiol and inadequate progesterone during early pregnancy both decrease embryo survival & pregnancy maintenance. Mechanistic studies were begun by Miles City, Montana researchers in collaboration with Texas A&M University and University of Missouri scientists to determine how preovulatory estradiol improves embryo survival.
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.
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.