2006 Annual Report 1.What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? Why does it matter? Reproductive efficiency has a greater influence on the economic sustainability of commercial sheep production than does any other performance-related trait. This is because reproductive efficiency is a composite trait that affects the total weight of lambs weaned from a flock, and because commercial sheep are currently marketed on a live-weight basis. Indeed, flock reproductive efficiency is an integrated measure of age at puberty, capacity to produce and deliver adequate numbers of fertile spermatozoa, ovulation rate, ovum fertilization rate, embryo and fetal survival to parturition, prolificacy, milk yield of dams, postnatal survival to weaning, interval between pregnancies, reproductive lifespan, and ability to cope with a variety of environmental stressors. In addition, genotype and nutrient intake and utilization affect each of the traits comprising reproductive efficiency. Thus, genotypic changes that favor phenotypic traits, such as growth rate, muscling, and increased mature body size, must not be allowed to compromise reproductive efficiency. Current knowledge of each component of reproductive efficiency is not sufficient for the development of integrated production systems to optimize nutrient utilization, while allowing producers to respond effectively to market forces, such as consumer demands associated with meat quantity, quality, and flavor, with the confidence that reproductive efficiency will not be compromised. Thus, a thorough understanding of each component of reproductive efficiency is needed so that sheep can be selected to produce germplasm that will result in offspring appropriate for various management systems. In addition, cost effective methods are needed for efficient production and industry-wide delivery of superior sheep germplasm to ensure a high quality product for consumers. Therefore, this project is designed to improve economically important traits of sheep, determine how to mitigate the effects of stressors that divert nutrients away from reproduction and overall production, and maintain or improve reproductive efficiency. The specific objectives are to. 1)develop and validate nonsurgical, transcervical artificial insemination procedures for sheep,. 2)determine whether manipulating uterine immune functions will reduce the incidence of uterine bacterial contamination and prevent subsequent reductions in pregnancy and lambing rates, 3) evaluate different biological types of sheep for reproductive efficiency, rate and efficiency of growth, carcass composition, meat quality, and mature size, 4) determine whether strategic nutrient intervention will mitigate the negative effects of production stressors on growth, health, and reproductive processes and on skeletal muscle nutrient composition, and. 5)develop and validate methods for characterizing sexual performance of rams and reproductive efficiency of their daughters. Results from this project will allow us to improve economically important production traits of sheep without compromising reproductive efficiency. This project addresses problems defined in the Reproductive Efficiency; Genetic Improvement; Nutrient Intake and Use; Growth and Development; and Product Quality components of the Action Plan for NP 101, Food Animal Production. Accomplishing the objectives for this project will allow us to. 1)produce and transfer to the industry recommendations and genetic selection tools that can be used to improve lifetime reproductive performance of ewes and rams, enhance the rate and efficiency of growth, and improve carcass composition and meat quality; 2) transfer effective, nonsurgical artificial insemination procedures to the private sector;. 3)transfer an effective, nonantibiotic-based method for enhancing host immunity to reduce bacterial contamination in the uterus and improve reproductive success, and. 4)prescribe nutrient management strategies for enhancing sheep tolerance to stressors and optimizing production efficiencies. 2.List by year the currently approved milestones (indicators of research progress) Year 1 (FY 2004) Further develop and validate nonsurgical, transcervical artificial insemination (TC-AI) procedures for sheep, and compare the efficacy of transcervical methods with established laparoscopic procedures. Determine whether exogenous prostaglandin F2alpha (PGF2alpha) induces uterine secretion of PGF2alpha, up-regulates uterine immune functions, and reduces the severity of uterine infections, even if progesterone is maintained at luteal-phase concentrations. Define selenium balance and tissue distribution in growing wethers that have been fed supranutritional amounts of selenium from an organically bound source. Determine whether exposure of rams to estrual ewes at an early age and then as adults will improve sexual behavior of the rams in serving capacity tests. Begin evaluating different biological types of sheep for reproductive efficiency, rate and efficiency of growth, carcass composition, meat quality, and mature size. Use quantitative genetic methods to identify physical and physiological criteria for enhancing reproductive efficiency and other economically important traits, including meat quality, quantity, and flavor. Year 2 (FY 2005) Establish the influence of time and dietary concentration of selenium on selenium distribution in growing wether lambs. Determine whether a ram's sexual behavior classification can be used to predict breeding efficiency in a competitive-mating environment. Begin developing a new white-faced composite terminal sire line that will better enable sheep producers to meet target market specifications with commercial lambs, resulting in a more desirable end product that meets consumer demands without sacrificing reproductive efficiency. Year 3 (FY 2006) Determine whether exogenous PGF2alpha treatment will enhance uterine health and improve pregnancy and lambing rates. Determine the effects of uterine infection and nutrient stressors on nutrient balance and metabolism in splanchnic and hind limb tissues of growing ewe lambs. Further determine whether exposure of adult rams to estrual ewes before serving capacity tests will provide more reliable serving capacity test scores. Determine whether a single cohort serving capacity test will provide a rapid and reliable method for discriminating between high-performing and low-performing rams. Determine whether sexual behavior classification based on serving capacity tests can be used to predict the breeding performance of rams in single-and multiple-sire breeding regimens. Determine whether calpastatin activity can be determined through an antemortem biopsy procedure and whether activity that is correlated with the traditional method of measuring activity in postmortem longissimus muscle. Determine whether acute antemortem management stress negatively affects quality and nutritive composition of skeletal muscle. Year 4 (FY 2007) Establish the amount of selenium and D-alpha-tocopherol needed to mitigate the negative effects of uterine infection. 4a.List the single most significant research accomplishment during FY 2006. Strategically increasing fetal selenium: Because of the limited accessibility and regulatory restrictions of many rangelands, providing supplemental selenium to ewes grazing selenium-deficient forages is difficult and sometimes impossible. Strategic nutrient-delivery solutions enable producers to overcome obstacles that limit production. Scientists at the U.S. Sheep Experiment Station, Dubois, Idaho, and North Dakota State University, Fargo, fed ewes supranutritional organically-bound selenium during late pregnancy and increased fetal muscle selenium. Based on these data, selenium supplementing strategies are being developed that provide a “stored form” of selenium for the lamb when dietary selenium is limiting. This research contributes to NP 101, Food Animal Production, components addressing Nutrient Intake and Use; Growth and Development; and Product Quality. 4b.List other significant research accomplishment(s), if any. Using novel grains to improve micronutrient utilization: Undigested phytate phosphorus can bind essential minerals in the digestive tract making them unavailable to the animal. The rapid passage rate of concentrate finishing rations in digestive tracts of sheep and cattle allow passage of undigested phytate to the small intestine. In cooperation, scientists at three ARS research units in Dubois, Aberdeen, and Kimberly, Idaho, replaced common-variety with low-phytate mutant variety barley grain in diets fed to finishing lambs and increased calcium, iron, magnesium, and zinc absorption. These results, which contribute to NP 101, Food Animal Production, components addressing Nutrient Intake and Use and Growth and Development, were summarized and submitted to a refereed journal for publication. Based on these data, nutrient-management strategies using low-phytate mutant grains to enhance mineral utilization in lamb-finishing programs can be developed. Improving reproductive efficiency of rams: Scientists at the U.S. Sheep Experiment Station, Dubois, Idaho, determined that rams with above-average serving capacity test scores bred more ewes and sired more lambs than did rams with below-average serving capacity test scores, when the rams were challenged to individually breed 9 to12 ewes daily. By contrast, when the same rams needed to breed only 1 or 2 ewes daily, the above-average rams were not superior to the below-average rams. The data indicate that, under typical large-scale reproductive management systems for commercial sheep, rams with below-average serving capacity test scores will reduce overall flock reproductive efficiency. This research contributes to NP 101, Food Animal Production, Reproductive Efficiency, and the data are being prepared for submission to a peer-reviewer scientific journal. The methods for scoring the rams are practical and will be transferred to the sheep industry. 4c.List significant activities that support special target populations. None. 4d.Progress report. None. 5.Describe the major accomplishments to date and their predicted or actual impact. National and international livestock producers, special-interest associations, and regulatory groups need information describing supranutritional (dietary) use and benefits of selenium naturally inherent in high-selenium feedstuffs. Methods for strategic manipulation of selenium status and nutrient management to offset infection stress and long-term selenium deficiency were developed and contribute to NP 101, Food Animal Production, Components I. Reproductive Efficiency, a. Embryo, Fetal, and Neonatal Development and Survival; III. Product Quality (pre-harvest), a. Interactions of Genetics and Nutrition; VI. Growth and Development, b. Tissue Growth and Development; and VII. Nutrient Intake and Utilization, b. Interactions Affecting Reproduction, d. Minimizing Production Losses, and e. Nutrient Use and Feed Evaluation. These methods, which rely on grains that are naturally enriched with organically-bound selenium, can be used to enhance selenium status of sheep, improve the ability of sheep to manage common infections, and minimize nutrient wastage due to improper use of mineral supplements. The methods can also be used to enrich sheep muscle foods with organically-bound selenium and help humans meet their selenium requirements. The National Research Council (Mineral Tolerance of Animals, 2005; Nutrient Requirements of Small Ruminants, in review) has used this research to increase the suggested upper limit of selenium for sheep and cattle diets. 6.What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end-user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Information regarding dietary selenium has been published in several refereed journals, an international symposium proceeding, and several scientific meeting proceedings, and presented (via invitation) at scientific-, marketing-, and producer-based group meetings. Upon request, information relating to the supranutritional use of selenium in livestock diets has been transferred to the committee charged with revision of the 7th Edition of the Nutrient Requirements for Small Ruminants (National Research Council). 7.List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). Presentation on "Nutrient management research at the U.S. Sheep Experiment Station," Annual Meeting Idaho Wool Growers Association, November 2006. Presentation on "Strategic Use of High Selenium Feedstuffs to Alleviate Selenium Deficiency," Annual Meeting Oregon Sheep Growers Association, December 2005. Presentations on "Selenium and Small Ruminant Production" and “Small Ruminant Nutrient Management,” Annual Meeting Utah Sheep and Goat Day, January 2006. Review Publications Stellflug, J.N., Cockett, N.E., Lewis, G.S. 2006. The relationship between sexual behavior classifications of rams and lambs sired in a competitive breeding environment. Journal of Animal Science. 84:463-468. Stellflug, J.N. 2006. Comparison of cortisol, luteinizing hormone, and testosterone responses to a defined stressor in sexually inactive rams and sexually active female-oriented and male-oriented rams. Journal of Animal Science. 84:1520-1525. Leeds, T.D., Lewis, G.S. 2006. Breed Comparisons and Trends for Ewe Productivity and Lamb Growth Traits in Sheep Managed as Contemporaries in a Western Range System. Proceedings of the Western Section of the American Society of Animal Science. 57:86-89. Traul, D., Taus, N.S., Oaks, J.L., Lewis, G.S., Li, H. 2006. The upper respiratory tract of sheep is the predominant site of ovine herpesvirus-2 replication. International Herpesvirus Workshop. Paper No. 8-68. Wulster-Radcliffe, M.C., Seals, R.C., Lewis, G.S. 2005. Uterine Response to Multiple Inoculations with Arcanobacterium pyogenes and Escherichia coli in Nulliparous Ewes. American Journal of Reproductive Immunology. 54:249-261. Lewis, G.S., Wulster-Radcliffe, M.C. 2006. Prostaglandin F2ALPHA up regulates uterine immune defenses in the presence of the immunosuppressive steriod progesterone. American Journal of Reproductive Immunology. 56:102-111. Sheldon, I.M., Lewis, G.S., LeBlanc, S., Gilbert, R.O. 2006. Defining postpartum uterine disease in cattle. Theriogenology. 65:1516-1530.