Associate Professor, Extension Dairy Specialist Department of Animal and Veterinary Science Caldwell Research and Extension Center University of Idaho 16952 S. 10th Avenue Caldwell, Idaho 83607   Phone: 208-459-6365 FAX: 208-454-7612 Email: jdalton@uidaho.edu   PhD - 1999, Animal Science, Virginia Polytechnic Institute and State University RESEARCH INTERESTS: Reproductive Physiology RESEARCH SUMMARY: There is evidence that dairy profitability increases as pregnancy rate (PR) increases; therefore, it is financially important to address reproductive efficiency in dairy herds. Consequently, dairy research (and Extension) efforts focus on increasing PR through the development of, and (or) dissemination of information regarding scientifically sound, labor-efficient management practices aimed at optimizing conception rate (CR) and heat detection rate (HDR), which are components of pregnancy rate, as (HDR * CR) = PR. Specifically, my research interests focus upon increasing the efficiency of AI in dairy cattle. Recently, together with Dr. Amin Ahmadzadeh (Associate Professor, University of Idaho), I have investigated 1) the effect of elapsed time between initial thawing of multiple .5-mL semen straws and AI on conception rates in dairy cattle, and 2) conception rates following detection of estrus and timed AI in dairy cows synchronized using GnRH and PGF2?. Currently, Dr. Ricardo Chebel, (Assistant Professor, University of Idaho), and I are investigating the effect of synchronization protocols on 1) follicular development, and 2) reproductive and economic performance in dairy heifers.   REPRESENTATIVE PUBLICATIONS: Dalton, J.C., R. Manzo, A. Ahmadzadeh, B. Shafii, W. J. Price, and J. M. DeJarnette. 2005. Short Communication: Conception rates following detection of estrus and timed AI in dairy cows synchronized using GnRH and PGF2?. J. Dairy Sci. 88:4313-4316. Dalton, J.C., A. Ahmadzadeh, B. Shafii, W.J. Price, and J.M. DeJarnette. 2004. Effect of thawing multiple 0.5-ml semen straws and sequential insemination number on conception rates in dairy cattle. J. Dairy Sci. 87:972-975. Dalton JC, Nadir S, Bame JH, Noftsinger M, Nebel RL, Saacke RG. (2001) Effect of time of insemination on number of accessory sperm, fertilization rate, and embryo quality in nonlactating dairy cattle. J Dairy Sci. 84(11):2413-8. Dalton JC, Nadir S, Bame JH, Noftsinger M, Saacke RG. (2000) The effect of time of artificial insemination on fertilization status and embryo quality in superovulated cows. J. Animal Sci. 78:2081-2085. Saacke RG, Dalton JC, Nadir S, Nebel RL, Bame JH. (2000) Relationship of seminal traits and insemination time to fertilization rate and embryo quality. Anim Reprod Sci. 60-61:663-77. Review. Dalton JC, Nadir S, Bame JH, Saacke RG. (1999) Effect of a deep uterine insemination on spermatozoal accessibility to the ovum in cattle: a competitive insemination study. Theriogenology. 51(5):883-90. Bame JH, Dalton JC, Degelos SD, Good TE, Ireland JL, Jimenez-Krassel F, Sweeney T, Saacke RG, Ireland JJ. (1999) Effect of long-term immunization against inhibin on sperm output in bulls. Biol Reprod. 60(6):1360-6.