2003 Annual Report 1.What major problem or issue is being resolved and how are you resolving it? Compatibility between beef cattle type (i.e., breed) and the environment is critical in harsh environmental zones such as the subtropics. Cattle breeds adapted to warm climates are limited to the Zebu breeds, primarily the American Brahman. Several characteristics of purebred Brahman cattle are undesirable and include poor reproductive and feedlot performance, carcass quality including meat tenderness, temperament, and neonate survivability. Solving these problems requires that we first gather knowledge about the genetic variation for important traits (i.e., carcass quality) in breeds currently being used in the subtropical U.S.A. Identification of tender Brahman sire lines or families would allow cow-calf producers to select bulls from these families to improve product quality and marketability. Another approach is the introduction of improved genetics from other countries of the world that are adapted to tropical environments. 2.How serious is the problem? Why does it matter? From an economic standpoint, over 50% of cash receipts from farm marketings (90 billion dollars per year) are from livestock and livestock products. Nearly 45% of cash receipts from farm marketings of livestock and livestock products are cattle and calves (40 billion dollars per year). Nearly thirty percent of the cattle in the U.S.A. are estimated to have some percentage Brahman breeding. The widespread use of Brahman breeding by commercial beef producers throughout the southern regions of the U.S.A. demonstrates the economic value placed on tolerance to heat, humidity, and diseases including parasites. Due to perceived problems primarily associated with poor feedlot performance and carcass quality including meat tenderness, crossbred feeder calves exhibiting Brahman characteristics, such as long ears or humps, are often heavily discounted by cattle buyers. 3.How does it relate to the National Program(s) and National Program Component(s) to which it has been assigned? This research evaluates and preserves tropically adapted beef cattle breeds in the subtropics with potential for increasing production efficiency and improving marketability with emphasis on reproductive efficiency and product quality, which contributes to National Program 101, Food Animal Production. The evaluations of different beef cattle breeds are conducted in cooperation with other ARS locations and universities across a range of nutrient and location variables in the subtropics. Research on developing cattle production systems for the subtropical U.S.A. is in cooperation with USDA-ARS Meat Animal Research Center. 4.What were the most significant accomplishments this past year? A. Single Most Significant Accomplishment during FY 2003: Brahman-cross cattle are well suited for use in the subtropical United States because of their adaptation to adverse conditions; however, this is at least partially negated by the lower prices paid for Brahman-cross calves because of poor carcass quality especially tenderness. The offspring from 27 Brahman sires was evaluated at the Subtropical Agricultural Research Station in Brooksville, FL, for various attributes including carcass quality. Heritability estimates for traits related to palatability and tenderness in purebred Brahman cattle were obtained from subsequent genetic analyses, and included low estimates (< 0.2) for tenderness (after seven, 14, and 21 days of aging), amount of connective tissue, juiciness, flavor intensity, off-flavor, and calpastatin (enzyme responsible for inhibiting the normal postmortem tenderization of beef; expressed in high levels in beef from Brahman cattle) activity. In cooperation with Dr. Don Franke, these results were combined with those from others to generate comparative breeding values for tenderness and other carcass quality traits for 179 Brahman sires; producers that use Brahman cattle will be able to use these results to select bulls for improvement of beef tenderness and carcass quality. B. Other Significant Accomplishment(s), if any: C. Significant Accomplishments/Activities that Support Special Target Populations. 5.Describe the major accomplishments over the life of the project, including their predicted or actual impact. In our evaluation of reproductive and maternal traits of tropically adapted crossbred beef cows, a greater percentage of Tuli x Angus cows calved as five- and six-year-olds than did Brahman x Angus or Senepol x Angus cows, but no differences were observed at earlier ages. Brahman x Angus cows were larger and heavier than cows of the other breed crosses and their calves were heavier at weaning. In another long term study to evaluate the Romosinuano, a tropical adapted breed native to Colombia, we demonstrated that Romosinuano bulls and heifers reached puberty at relatively young ages that were earlier than Brahman and at lighter body weights. Additionally, Romosinuano heifers were observed to be as heat tolerant as Brahman heifers. 6.What do you expect to accomplish, year by year, over the next 3 years? In FY 2004, final data analysis will be completed and a refereed publication prepared for the evaluation of reproductive and maternal traits of tropically adapted crossbred beef cows. In FY 2005, final data analysis will be completed on feedlot growth of Brahman steers and heifers. In FY 2006, final data analysis will be completed on weaning traits of Romosinuano straightbred and crossbred calves. 7.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? Technology transfer of research findings and potential impacts were discussed with various producers, producer groups (e.g., National Cattlemen's Association and Florida Cattlemen¿s Association), and international visitors. Scientists at the unit interacted with several Brahman breeders from throughout the southern U.S. and with representatives of the American Brahman Breeders Association (ABBA) and Florida Brahman Association to discuss current and future research studies. Scientists at the unit met with scientists from Louisiana State University and ABBA representatives to work on the national evaluation of carcass and tenderness traits in Brahman cattle. Results (EPD) were provided to ABBA. Scientists at the unit were also involved in technical interaction with private Romosinuano cattle breeders from Mexico, Costa Rica, and Venezuela and with representatives from the Romosinuano breed association of Venezuela. A major constraint to technology transfer of beef cattle germplasm is that maximal production efficiency may only be achieved when animal genetic resources are matched to environmental resources. This is difficult in the subtropics where cows and calves must be adapted to hot and humid weather but after weaning calves are transported to other areas of the country and fed in feedlots in cooler climates. Therefore, genetics and breeding programs that take these factors into account are of extreme importance; however, relatively long generation intervals and genotype x environment interactions necessitate longer term breeding projects conducted across multiple environments. 8.List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: This does not replace your peer-reviewed publications listed below). "Do I Have the Cow that is the Most Efficient Producer for My Environment/Management Level?," 2003 Beef Cattle Short Course, Gainesville, FL, April 30-May 2, 2003. "New Research at STARS," Florida Cattlemen¿s Association Annual Meeting, Marco Island, FL, June 18-20, 2003. Review Publications Block, J., Chase, C.C., Hansen, P.J. 2002. Inheritance of resistance of bovine preimplantation embryos to heat shock: relative importance of the maternal versus paternal contribution. Journal of Molecular Reproduction and Development. 63:32-37. Paula-Lopes, F.F., Chase, C.C., Al-Katanani, Y.M., Krininger Iii, C.E., Rivera, R.M., Tekin, S., Majewski, A.C., Ocon, O.M., Olson, T.A., Hansen, P.J. 2003. Genetic divergence in cellular resistance to heat shock: differences between breeds developed in temperate vs. hot climates in responses of preimplantation embryos, reproductive tract tissues & lymphocytes to elevated culture. Reproduction.125:285-294. Olson, T.A., Lucena, C., Chase, C.C., Jr., Hammond, A.C. Evidence of a major gene influencing hair length and heat tolerance in Bos taurus cattle. Journal of Animal Science. 2003. v. 81. p. 80-90. Riley, D.G., Chase, C.C., Hammond, A.C., West, R.L., Johnson, D.D., Olson, T.A., Coleman, S.W. 2003. Estimated genetic parameters for palatability traits of steaks from Brahman cattle. Journal of Animal Science. 81:54-60 Riley, D.G., Chase, C.C., Olson, T.A., Hammond, A.C., Coleman, S.W. 2003. Reproductive and maternal performance of f1 brahman-, senepol-, and tuli-angus cows bred to charolais bulls as 3- to 8-yr olds [abstract]. Journal of Animal Science.81(2):4 Koch, J.W., Tatman, S.R., Chase, C.C., Welsh, Jr., T.H., Randel, R.D. 2003. Comparison of testicular and epididymal sperm content in angus, brahman, and romosinuano bulls. Journal of Animal Science Vol. 81,(Suppl.2)P 13. Kostenbauder, M.J., Coleman, S.W., Chase, C.C., Kunkle, W.E., Hall, M.B., Martin, F.G. 2003. Supplementing bahiagrass hay with molasses or molasses-urea with or without soybean hulls [abstract]. Journal of Animal Science. 81(2):9. Riley, D.G., Barling, K.S., Chase, C.C., Olson, T.A., Hammond, A.C., Coleman, S.W. 2003. Odds ratios for failure to calve and wean for senepol- and tuli-angus cows compared to brahman- angus cows. Journal of Animal Science 81 (suppl-1): 254.