Progress 07/05/12 to 12/31/12
OUTPUTS: Activities included conducting and analyzing experiments along with mentoring two graduate students involved in this project. Events included presentation of these results at one national and one international professional conference to inform scientists of research results. In addition, results were disemminated to beef cattle producers and allied industry personnel at the Annual Texas A&M Beef Cattle Short Course. Products included the enhancement of methods to select cattle for more efficient production and the graduation of one doctoral student in Animal Science. PARTICIPANTS: David Forrest served as the Principal Investigator and coordinated project design and implementation. Gordon Carstens served as a Co-Investigator and directed the studies to elucidate the relationships among feed efficiency and reproductive traits in bulls. Partner organizations included Ovagenix located in Bryan, TX, Bioniche Animal Health in Bogart, GA, and JBS Five Rivers Cattle Feeding LLC in Greeley, CO. Collaborators included scientists located at Texas AgriLife Research Centers in Overton and Uvalde, TX along with scientists at Oklahoma State University and The Ohio State University. Two graduate students received training associated with this project. A.N. Hafla conducted the bull research as a component of her Ph.D. dissertation. J.W. Thorne conducted the embryo recipient research as a component of his M.S. thesis. Both graduate students experienced professional development through presentation of research results at professional meetings. TARGET AUDIENCES: One target audience consisted of scientists, industry professionals and students who are interested in the fundamental mechanisms that regulate the reproductive processes that are responsible for successful conception and gestation. Another target audience included beef cattle producers who are interested in incorporating management practices to increase reproductive efficiency. Efforts to deliver the results from this project included seminars, classroom teaching, presentations at professional society meetings and presentations at producer meetings. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
A meta-analysis of five postweaning performance trials and three breed types expanded our knowledge of relationships between feed efficiency and bull fertility traits. Inclusion of feed efficiency into a selection index does not appear to adversely affect pubertal development or potential fertility of bulls. These results allow beef cattle producers increased confidence in incorporating efficiency of gain into selection practices without compromising pregnancy rate of females mated to the more efficient bulls. A hormone administration protocol hypothesized to enhance luteal function in bovine embryo transfer recipient females failed to increase number or size of corpora lutea and did not result in a higher pregnancy rate. Further investigation of varying dose, timing or diluent of the hormone will be required before this technology will merit transfer to the beef cattle industry.
- Hafla, A.N., Lancaster, P.A., Carstens, G.E., Forrest, D.W., Fox, J.T., Forbes, T.D.A., Davis, M.E., Randel, R.D., and Holloway, j.W. 2012. Relationships between feed efficiency, scrotal circumference, and semen quality traits in yearling bulls. J. Animal Science 90:3937-3944.
- Thorne, J.W., Looney, C.R., Hasler, J.F., Hockley, D.K., and Forrest, D.W. 2012. Fertillity of beef recipients following a fixed-time embryo transfer protocol which included follicle stimulating hormone diluted in hyaluronan. Reproduction, Fertility and Development Special Issue 25(1):229-230. (abstract).