Armstrong, D. V. 1994. Heat stress interactions with shade and cooling. J. Dairy Sci. 77:2044-2050.
Badinga, L. R. J. Collier, W. W. Thatcher and J. Wilcox. 1985. Effects of climatic and management factors on conception rate in subtropical environment. J. Dairy Sci. 68:78-85.
Badinga, L., W. W. Thatcher, T. Diaz, M. Drost and D. Wolfenson. 1993. Effects of environmental heat stress on follicular development and steroidogenesis in lactating Holstein cows. Theriogenology 39:797-810.
Burke, J. M., R. L. De La Sota, C. A. Risco, C. R. Staples, E. J-P. Schmitt and W. W. Thatcher. 1996. Evaluation of timed insemination using a gonadotropin-releasing hormone agonist in lactating dairy cows. J. Dairy Sci. 79:1385-1393.
Cartmill, J. A., S. Z. El-zarkouny, B. A. Hensley, G. C. Lamb and J. S. Stevenson. 2001a. Stage of cycle, incidence and timing of ovulation, and pregnancy rates in dairy cattle after three timed breeding protocols. J Dairy Sci. 84:1051-1059.
Cartmill, J. A., S. Z. El-zarkouny, B. A. Hensley, T. G. Ronzell, J. F. Smith and J. S. Stevenson. 2001b. An alternative AI breeding protocol for dairy cows exposed to elevated ambient temperatures before or after calving or both. J. Dairy Sci. 84:799-806.
De La Sota, R. L., J. M. Burke, C. A. Risco, F. Moreira, M. A. Delorenzo and W. W. Thatcher. 1998. Evaluation of timed insemination during summer heat stress in lactating dairy cattle. Theriogenology 49:761-770.
Ferguson, J. D. and D. T. Galligan. 1993. Prostaglandin synchronization programs in dairy herds (part I). Compend. Contin. Educ. Pract. Vet. 15:646-655.
Folman, Y., M. Rosenberg, Z. Herz and M. Davidson. 1973. The relationship between plasma progesterone concentration and conception in post-partum dairy cows maintained on two levels of nutrition. J. Reprod. Fertil. 34:267-278.
Gilad, E., R. Meidan, A. Berman, Y. Graber and D. Wolfenson. 1993. Effect of heat stress on tonic and GnRH-induced gonadotrophin secretion in relation to concentration of oestradiol in plasma of cyclic cows. J. Reprod. Fertil. 99:315-321.
Gong, J. G., B. K. Campbell, T. A. Bramley, C. G. Gutierrez, A. R. Peters and R. Webb. 1996. Suppression in the secretion of follicle-stimulating hormone and luteinizing hormone and ovarian follicle development in heifers continuously infused with a gonadotropin- releasing hormone agonist. Biol. Reprod. 55:68-74.
Howell, J. L., J. W. Fuquay and A. E. Smith. 1994. Corpus luteum growth and function in lactating Holstein cows during spring and summer. J. Dairy Sci. 77:735-739.
Ingraham, R. H., R. W. Stanley and W. C. Wagner. 1979. Seasonal effects of tropical climate on shaded and nonshaded cows as measured by rectal temperature, adrenal cortex hormones, thyroid hormone, and milk production. Am. J. Vet. Res. 40:1792-1797.
Jemmeson, A. 2000. Synchronizing ovulation in dairy cows with either two treatments of gonadotropin-releasing hormone and one of prostaglandin or two treatments of prostaglandin. Aust. Vet. J. 78:108-111.
Kesler, D. J., H. A. Garverick, R. S. Youngquist, R. C. Elmore and C. J. Bierschwal. 1978. Ovarian and endocrine responses and reproductive performance following GnRH treatment in postpartum dairy cows. Theriogenology 9:363-369.
Larson, L. L. and P. J. H. Hall. 1992. Regulation of estrous cycles in dairy cattle: a review. Theriogenology 38:255-267.
Mialot, J. P., G. Laumonnier, C. Ponsart, H. Fauxpoint, E. Barassin, A. A. Ponter and F. Deletang. 1999. Postpartum subestrus in dairy cows: Comparison of treatment with prostaglandin $F_2\alpha$
or GnRH+ prostaglandin $F_2\alpha$
+GnRH. Theriogenology 52:901-911.
National Research Council. 1989. Nutrient Requirements of Dairy Cattle. 5th Ed. National Academy Sci. Washington, DC.
Pursley, J. R., M. C. Wiltbank, J. S. Stevenson, J. S. Ottobre, H. A Garverick and L. L. Anderson. 1997a. Pregnancy rates per artificial insemination for cows and heifers inseminated at a synchronized ovulation or synchronized estrus. J. Dairy Sci. 80:295-300.
Pursley, J. R., M. O. Mee and M. C. Wiltbank. 1995. Synchronization of ovulation in dairy cows using PGF$_2\alpha$
and GnRH. Theriogenology 44:915-923.
Pursley, J. R., M. R. Kosorok and M. C. Wiltbank. 1997b. Reproductive management of lactating dairy cows using synchronization of ovulation. J. Dairy Sci. 80:301-306.
Putney, D. J., S. Mullins, W. W. Thatcher, M. Drost and T. S. Gross. 1989. Embryonic development in superovulated dairy cattle exposed to elevated ambient temperatures between the onset of estrus and insemination. Anim. Reprod. Sci. 19:37-51.
Rosenberg, M., M. Kaim, Z. Herz and Y. Folman. 1990. Comparison of methods for the synchronization of estrous cycles in dairy cows. 1. Effects on plasma progesterone and manifestation of estrus. J. Dairy Sci. 73:2807-2816.
Ryan, D. P., J. F. Prichard, E. Kopel and R. A. Godke. 1993. Comparing early embryo mortality in dairy cows during hot and cool seasons of the year. Theriogenology 39:719-737.
Ryan, D. P., S. Snijders, H. Yaakub and K. J. O'Farrell. 1995. An evaluation of estrous synchronization programs in reproductive management of dairy herd. J. Anim. Sci. 78:3687-3695.
SAS Institute Inc. 1998. SAS/STAT User's Guide: Version 7 Edition. SAS. Institute Inc. Cary NC.
Savio, J. D., W. W. Thatcher, G. R. Morris, K. Entwistle, M. Drost and M. R. Mattiacci. 1993. Effects of induction of low plasma progesterone concentrations with a progesterone-releasing intavaginal device on follicular turnover and fertility in cattle. J. Reprod. Fertil. 98:77-84.
Stevenson, J. S., Y. Kobayashi and K. E. Thomson. 1999. Reproductive performance of dairy cows in various programmed breeding systems including OvSynch and combinations of gonadotropin-releasing hormone and prostaglandin F$_2$. J. Dairy Sci. 82:506-515.
Twagiramungu, H., L. A. Guilbault, J. Prolux, R. Ramkumar and J. J. Dufour. 1994. Histological populations and atresia of ovarian follicles in post-partum cattle treated with an agonist of gonadotropin-releasing hormone. J. Anim. Sci. 72:192-200.
Vasconcelos, J. L. M., R. W. Silcox, G. J. Rosa, J. R. Pursley and M. C. Wiltbank. 1997. Synchronization rate, size of the ovulatory follicle, and conception rate after synchronization of ovulation with GnRH on different days of the estrous cycle. J. Dairy Sci. 80(Supp. l):178(Abstr.).
Vasconcelos, J. L. M., R. W. Silcox, J. A. Lacerda, J. R. Pursley and M. C. Wiltbank. 1998. Pregnancy rate, pregnancy loss, and response to heat stress after AI at 2 different times from ovulation in dairy cows. Biol. Reprod. 56(Supp. l):140(Abstr.).
Wilson, S. J., R. S. Marion, J. N. Spain, D. E. Spiers, D. H. Keisler and M. C. Lucy. 1998. Effects of controlled heat stress on ovarian function of dairy cattle. 1. Lactating cows. J. Dairy Sci. 81:2124-2131.
Wise, M. E., D. V. Armstrong, J. T. Huber, R. Hunter and F. Wiersma. 1988a. Hormonal alterations in the lactating dairy cow in response to thermal stress. J. Dairy Sci. 71:2480-2485.
Wise, M. E., R. E. Rodriguez, D. V. Armstrong, J. T. Huber, F. Wiersma and R. Hunter. 1988b. Fertility and hormonal responses to temporary relief of heat stress in lactating dairy cow. Theriogenology 29:1027-1035.
Wolfenson, D., W. W. Thatcher, L. Badinga, J. D. Savio, R. B. J. MedanLew, R. Braw-Tal and A. Berman. 1995. Effect of heat stress on follicular development during the estrous cycle in lactating dairy cattle. Biol. Reprod. 52:1106-1113.
Xu, Z. Z. and L. J. Burton. 2000. Estrus synchronization of lactating cows with GnRH, progesterone, and prostaglandin F$_2\alpha$ J. Dairy Sci. 83:471-476.
Xu, Z. Z., G. A. Verkerk, J. F. Mee, S. R. Morgan, B. A. Clark, C. R. Burke and L. J. Burton. 2000. Progesterone and follicular changes in postpartum noncyclic dairy cows after treatment with progesterone and estradiol or with progesterone, GnRH, PGF$_2\alpha$
, and estradiol. Theriogenology 54:273-282.
Xu, Z. Z., L. J. Burton and K. L. Macmillan. 1997. Reproductive performance of lactating dairy cows following estrus synchronization regimess with PGF$_2\alpha$
and progesterone. Theriogenology 47:687-701.