Ashworth CJ, Sales DI and Wilmut I, 1989. Evidence of an association between the survival of embryos and periovulatory plasma progesterone concentration in the ewe. Journal of Reproduction and Fertility 87: 23-32.
Atsan T, Emsen E, Yaprak M, Dagdemir V and Diaz GAG, 2007. An economic assessment of differently managed sheep flocks in eastern turkey. Italian Journal of Animal Science 6: 407-414.
Bartolome JA, Melendez P, Kelbert D, Swift K, McHale J and Hernandez J, 2005. Strategic use of gonadotrophin-releasing hormone (GnRH) to increase pregnancy rate and reduce pregnancy loss in lactating dairy cows subjected to synchronization of ovulation and timed insemination. Theriogenology 63: 1026–1037.
Bazer FW, Ott TL and Spencer TE, 1998. Maternal recognition of pregnancy: comparative aspects- a review. Trophoplast Research 12: 375-386.
Beck NFG, Green A, Khan TH and Khalid M, 1998. The effects of buserelin (GnRH analogue) or hCG treatment on luteal weight and embryonic development during early pregnancy in the ewe. Journal of Reproduction and Fertility 21: 95-96.
Beck NFG, Jones M, Davies B, Mann GE and Peters AR, 1996. The effect of GnRH analogue (buserelin) treatment on day 12 post-mating on ovarian structure and plasma progesterone and estradiol concentration in ewes. Animal Science 63: 407-412.
Beck NFG, Peters AR and Williams SP, 1994. The effect of GnRH agonist (buserelin) treatment on day 12 post mating on the reproductive performance of ewes. Animal Production 58: 243-247.
Breuel KF, Spitzer JC and Henricks DM, 1989. Systemic progesterone concentration following human chorionic gonadotropin administration at various times during the estrous cycle in beef heifers. Journal of Animal Science 67: 1564-1572.
Cam MA and Kuran M, 2004. Effects of a single injection of hCG or GnRH agonist on day 12 post mating on fetal growth and reproductive performance of sheep. Animal Reproduction Science 80: 81–90.
Cam MA, Kuran M, Yildiz S and Selcuk E, 2002. Fetal growth and reproductive performance in ewes administered GnRH agonist on day 12 post-mating. Animal Reproduction Science 72: 73–82.
Drew SB and Peters AR, 1994. Effect of buserelin on pregnancy rates in dairy cows. Veterinary Record 134: 267-269.
Farin CE, Moeller CL, Hayan H, Gamboni F, Sawyer HR and Niswender GD, 1988. Effect of luteinizing hormone and human chorionic gonadotrophin on cell populations in the ovine corpus luteum. Biology of Reproduction 38: 413-421.
Garrett JE, Geisert RD, Zavy MT and Morgan GL, 1988. Evidence for maternal regulation of early conceptus growth and development in beef cattle. Journal of Reproduction and Fertility 84: 437-446.
Jubb TF, Abhayaratne D, Maimo J and Andeson GA, 1990. Failure of an intramuscular injection of an analogue of gonadotrophin releasing hormone 11 to 13 days after insemination to increase pregnancy rates in dairy cattle. Australian Veterinary Journal 67: 359-361.
Kelly CM, Hoyer PB and Wise ME, 1988. In-vitro and in-vivo responisiveness of the corpus luteum of the mare to gonadotrophin stimulation. Journal of Reproduction and Fertility 84: 593-600.
Khan TH, Beck NFG and Khalid M, 2007. The effects of GnRH analogue (buserelin) or hCG (Chorulon) on Day 12 of pregnancy on ovarian function, plasma hormone concentrations, conceptus growth and placentation in ewes and ewe lambs. Animal Reproduction Science 102: 247-257.
Khan TH, Beck NFG and Khalid M, 2009. The effect of hCG treatment on Day 12 post-mating on ovarian function and reproductive performance of ewes and ewe lambs. Animal Reproduction Science 116: 162-168.
Khan TH, Beck NFG, Khalid M and Mann GE, 2001. Effect of post-mating GnRH analogue buserelin treatment on prostaglandin F2α release in sheep. Animal Reproduction Science 27: 107-115.
Khan TH, Hastie PM, Beck NFG and Khalid M, 2003. hCG treatment on day of mating improves embryo viability and fertility in ewe lambs. Animal Reproduction Science 76: 81-89.
Lankford LM, Yates DT, Halalsheh RA, Black PL, Hallford DM and Ross TT, 2010. Effects of human chorionic gonadotropin on serum progesterone concentrations, embryonic survival, and lambing rates in ewes. Proceeding of 2010 Western Section American Society of Animal Sciences 61: 153-157.
Mann GE, Fray MD and Lamming GE, 2006. Effects of time of progesterone supplementation on embryo development and interferon-tau production in the cow. Veterinary Journal 171: 500-503.
Mann GE and Lamming GE, 2001. Relationship between maternal endocrine environment, early embryo development and inhibition of the luteolytic mechanism in cows. Reproduction 121:175-180.
Mann GE, Lamming GE and Fisher PA, 1998. Progesterone control of embryonic interferon-τ production during early pregnancy in the cow. Journal of Reproduction and Fertility 21: 37.
McMillan W, Knight TW and Macmillan KL, 1986. Effects of gonadotrophin releasing hormone (buserelin) on sheep fertility. Proceeding of New Zealand Society of Animal Production 46: 161–163.
Michels H, Vanmontfort D, Dewil E and Decuypere E, 1998. Genetic variation of prenatal survival in relation to ovulation rate in sheep: a review. Small Ruminant Research 29: 129–142.
Moeini MM, Alipour F and moghadam A, 2009. The effect of hCG on the reproduction performance in Lory sheep synchronized with different doses of pregnant mare serum gonadotrophin outside the breeding season. Asian Journal of Animal and Veterinary Advances 4: 9-15.
Moradi-Kor N, Sadeghi S and Ziaei N, 2012. Comparison reproductive Performance in Kermani ewes Treated with two synchronization methods and Subsequent eCG treatment out of the breeding season. International Journal of Biological Medicine Research 3: 1485-1489.
Nakao T, Hanzawa M, Nakada K, Moriyoshi M and Kawata K, 1995. Effect of buserelin administered at artificial insemination (AI) or 11-12 days after AI on conception rate in dairy cows. Journal of Dairy Science: 279 (abstract).
Nephew KP, Cardenas H, McClure KE, Ott TL, Bazer FW and Pope WF, 1994. Effects of administration of human chorionic gonadotropin or progesterone before maternal recognition of pregnancy on blastocyst development and pregnancy in sheep. Journal of Animal Science 72: 453-458.
Peters AR, 1996. Embryo mortality in the cow. Animal Breeding 64: 587-598.
Redden RR, Herron B. J, Martinez CH and Ross TT, 2006. Effects of hCG and progesterone Administered to Ewes Post Breeding on Serum Concentrations of progesterone and Estradiol. Proceeding of 2006 Western Section American Society of Animal Sciences 57: 32-35.
Ryan DP, Snijders S, Condon T, Grealy M, Sreenan J and O’farrell KJ, 1994, Endocrine and ovarian responses and pregnancy rates in dairy cows following the administration of a gonadotrophin releasing hormone analog at the time of artificial insemination or at mid-cycle post insemination. Animal Reproduction Science 34: 179-191.
Santos J E, Thatcher WW, Pool L and Overton MW, 2001. Effect of human chorionic gonadotropin on luteal function and reproductive performance of high-producing lactating Holstein dairy cows. Journal of Animal Science 79: 2881-2894.
Seguin BE, Oxender WD and Britt JH, 1977. Effect of human chorionic gonadotropin and gonadotropin-releasing hormone on corpus luteum function and estrous cycle duration in dairy heifers. American Journal of Veterinary Research 38:1153-1156.
Sheldon M and Dobson H, 1993. Effects of gonadotrophin releasing hormone administered 11 days after insemination on the pregnancy rates of cattle to the first and later services. Veterinary Record 133: 160-163.
Sirjani MA, Shahir MH, Kohram H and Zare-shahne A, 2011. Effect of gonadotropin-releasing hormone (GnRH) treatment on multiple birth in Afshari ewes. African journal of Biotechnology 10: 12358-12362.
Spencer TE, Burghardt RC, Johnson GA and Bazer FW, 2004a. Conceptus signals for establishment and maintenance of pregnancy. Animal Reproduction Science 82: 537-550.
Spencer TE, Johnson GA, Bazer FW and Burghardt RC, 2004b. Implantation mechanisms: insights from the sheep. Journal of Reproduction and Fertility 128: 657-668.
Thatcher WW, Meyer MD and Danet-Desnoyers G, 1995. Maternal recognition of pregnancy. Journal of Reproduction and Fertility Suppl. 49: 15-28.
Thatcher WW, Moreira F, Santos JEP, Mattos RC, Lopes FL, Pancarci SM and Risco CA, 2001. Effects of hormonal treatments on reproductive performance and embryo production. Theriogenology 55: 75-89.
Thatcher WW, Staples CR, Danet-Desnoyers G, Oldick B and Schmitt EP, 1994. Embryo health and mortality in sheep and cattle. Journal of Animal Science 72: 16–30.
Wilmut I, Sales DI and Ashworth CJ, 1986. Maternal and embryonic factors associated with prenatal loss in mammals. Journal of Reproduction and Fertility 76: 851-864.
Yildiz H, Kaygusuzoolu E, Kaya M and Cenesiz M, 2009. Effect of administration of GnRH on 12 day Post-mating on serum progesterone, luteinizing hormone levels, duration of cycle and pregnancy rate in cows. Pakistan Veterinary Journal 29: 110-114.