|Credentials:||1988 - Ph.D. Washington State University; Animal Sciences|
|Office:||Fort Keogh LARRL|
USDA-ARS, Fort Keogh LARRL
Develop beef cattle better suited for sustainable production
The long-term goal of research is to determine physiological processes by which genetic and environmental factors influence reproduction, thereby facilitating the ability to match cattle genotype with production environment. Research utilizes genomic, functional genomic and physiological approaches to identify key genes involved in controlling reproductive processes and determine how nutrition interacts with these genes to influence reproduction in cattle. Knowledge from this research is expected to result in the development of management and selection strategies that improve fertility and efficiency of beef production.
Jinks EM, MF Smith, JA Atkins, KG Pohler, GA Perry, MD MacNeil, AJ Roberts, RC Waterman, LJ Alexander and TW Greary. 2013. Preovulatory estradiol and the establishment and maintenance of pregnancy in suckled beef cows. J. Anim. Sci. 91:1176-1185.
Endecott RL, RN Funston, JT Mulliniks and AJ Roberts. 2013. JOINT ALPHARMA-BEEF SPECIES SYMPOSIUM: Implications of beef heifer development systems and lifetime productivity. J. Anim. Sci. 91:1329-1335
Mulliniks JT, ME Kemp, RL Endecott, SH Cox, AJ Roberts, RC Waterman, TW Geary, EJ Scholljegerdes and MK Petersen. 2013. Does β-hydroixybutyrate concentration influence conception date in young postpartum range beef cows? J. Anim. Sci. 91:2902-2909.
Funston RN, AF Summers and AJ Roberts. 2012. Implications of nutritional management for beef cow-calf systems. J. Anim. Sci. 90:2301-2307.
Funston RN, JL Martin, DM Larson and AJ Roberts. 2012. Nutritional aspects of developing replacement heifers. J. Anim. Sci. 90:1166-1171.
Geary TW, KJ Wells, DM Deavila, J Deavila, VA Conforti, DJ McLean, AJ Roberts, RC Waterman and JJ Reeves. (2011). “Effects of immunization against LHRH and treatment with trenbolone acetate on reproductive function of beef bulls and steers.” Journal of Animal Sciences 89:2086-2095.
Roberts AJ and DJ McLean (2011). “Differential gene expression in anterior pituitary glands from anestrous and cycling postpartum beef cows.” Journal of Animal Science 89(4): 1035-1041.
Underwood KR, JF Tong, et al. (2010). “Nutrition during mid to late gestation affects growth, adipose tissue deposition, and tenderness in cross-bred beef steers.” Meat Science 86(3):588-593.
Geary TW, RP Ansotegui, et al. (2010). “Effects of flunixin meglumine on pregnancy establishment in beef cattle.” Journal of Animal Science 88(3): 943-949.
Roberts AJ, TW Geary, EE Grings, RC Waterman and MD MacNeil. 2009. Reproductive performance of heifers offered ad libitum or restricted access to feed for a 140-d period after weaning. J. Anim. Scie. 87:3043-3052.
CG Elsik, RL Tellam, KC Worley, TA Gibbs…L. Alexander,…A. Roberts,…RC Waterman, …, MD MacNeil. 2009. The Genome Sequence of Taurine Cattle: A Window to Ruminant Biology and Evolution. Science 324:522-528.
Grings EE, AJ Roberts, TW Geary and MD MacNeil. Milk yield of primipatous beef cows from three calving systems and varied weaning ages. J. Anim. Sci, 2008. 86(3): p. 768-79.
Roberts AJ, SI Paisley, TW Geary, EE Grings, RC Waterman and MD MacNeil. Effects of restricted feeding of beef heifers during the postweaning period on growth, efficiency, and ultrasound carcass characteristics. J. Anim. Sci, 2007. 85(10): p. 2740-5.
Perry GA, MF Smith, AJ Roberts, MD MacNeil and TW Geary. 2007. Relationship between size of ovulatory follicle and pregnancy success in beef heifers. J. Anim. Sci. 85:684-689.
Waterman RC, EE Grings, TW Geary, AJ Roberts, LJ Alexander and MD MacNeil. Influence of seasonal forage quality on glucose kinetics of young beef cows. J. Anim. Sci. 2007. 85(10):p. 2582-95.
MacNeil MD, TW Geary, GA Perry, AJ Roberts and LJ Alexander. Genetic partitioning of variation in ovulatory follicle size and probability of pregnancy success in beef heifers. J. Anim. Sci. 2006. 54(7): p. 1646-50.
Roberts AJ, MJ Al-Hassan, PM Fricke and SE Echternkamp. Large variation in steroid concentrations and insulin-like growth factor binding proteins exists among individual small antral follicles collected from within cows at random stages of the estrous cycle. J. Anim. Sci. 2006. 84(10):p.2714-24.
Roberts AJ, J. Klindt and TG Jenkins. Effects of varying energy intake and sire breed on duration of postpartum anestrus, insulin like growth factor-1, and growth hormone in mature crossbred cows. J. Anim. Sci 2005. 83(7): p. 1705-14.
RN Funston, RJ Lipsey, TW Geary and AJ Roberts. (2005) Effect of administration of human chorionic gonadotropin after artificial insemination on concentrations of progesterone and conception rates in beef heifers. J. Anim. Sci. 83:1403-1405.
Perry GA, Smith MF, Lucy MC, Green JA, Parks TE, MacNeil MD, Roberts AJ, Geary TW. (2005) From the Cover: Relationship between follicle size at insemination and pregnancy success. Proc. Natl. Acad. Sci. USA. 102(14):5269-73.