The effect of post-mating hCG or progesterone administration on reproductive performance of Afshari × Booroola-Merino crossbred ewes

Abstract

To investigate the efficiency of hCG/CIDR after breeding to increase the reproductive performance, 35 synchronized ewes were mated with fertile rams and were assigned to three treatment groups. Ewes in hCG group (n = 12) received 400 IU hCG on day 11 post-mating, and ewes in CIDR group (n = 11) received CIDR from day 7 until day 19 post-mating. Ewes in the control group (n = 12) did not receive any treatment. Blood samples were collected on days 7, 12, 17, and 22 post-mating. Plasma P concentrations were higher on days 12 and 17 post-mating in hCG- and CIDR-treated groups (P < 0.05). However, the concentrations of P on day 22 post-mating in hCG and control groups were higher than that in CIDR group (P < 0.05). Ewes in hCG group produced more quadruplets (P < 0.05) and triplets, and as a result, they had a larger litter size (P < 0.05). The lamb mortality rate by weaning in hCG group (3.6%) was less than that in control (11.8%; P < 0.05) and CIDR (9.1%; P > 0.05) groups. Post-mating administration of hCG or CIDR did not affect the lamb birth weight in single and quadruplet births (P > 0.05), but the birth weight of twin lambs was higher in the hCG and CIDR groups (P < 0.05). Weaning weights of twin lambs were higher in the hCG and CIDR groups (P < 0.05). In conclusion, hCG/CIDR administration post-mating increased the maternal P concentrations and enhanced reproductive performance.

Effect of double GnRH injections on reproductive parameters in Awassi ewes receiving long-term progesterone

“…Therefore, it may be usefull that gonadotropic hormone injections are applied in order to support luteal structure and to increase progesterone levels in this critical term (Khan et al 2006). Rostami et al (2017) pointed out that GnRH injections applied between 7 and 19 days following mating may be important, although 12th day of gestation is critical for preventing luteolysis, because insufficient and abnormal luteal function in this period detrimentally affect embryonic development and cause embryonic loss (Spencer et al 2004). A study made by Beck et al (1996) reported that GnRH injection on day 12 post-mating improves reproductive outcome; these applications are essential for successful implantation and progression of gestation, supports follicular and luteal function with increased LH pulses, survival and quality of developing embryos can be improved during pre-implantation period (Khan et al 2007).…”

“…Gonadotropin releasing hormone (GnRH) or human chorionic gonadotropin (hCG) injections are applied concurrently with mating or just after in order to prevent embryonic and foetal loss or to increase reproductive performance in ewes (Beck et al 1994;Nephew et al 1994;Cam and Kuran 2004;Khan et al 2007;Ataman et al, 2013;Ahmadi and Mirzaei 2016;Rostami et al 2017). Embryonic loss generally results from inadequate early luteal function and insufficient progesterone levels during pre-implantation period (Spencer et al 2004).…”

“…During early luteal phase, inadequate or low progesterone levels generally cause to strike against embryonic development (Nephew et al 1991). For this reason, progesterone from corpus luteum is needed for embryonic implantation and development in uterus (Thatcher et al 2001) or exogenous progesterone applications may be needed to continue these vital processes for embryo (Davies and Beck 1992;Nephew et al 1994;Rostami et al 2017).…”

The effect of prostaglandin and gonadotrophins (GnRH and hCG) injection combined with the ram effect on progesterone concentrations and reproductive performance of Karakul ewes during the non‐breeding season

“…A higher plasma P 4 concentrations was reported in post‐mating hCG‐treated groups in Afshari × Booroola‐Merino crossbred ewes by Rostami et al. (2017). Injection of GnRH on the day of oestrus or at the time of mating and 7 or 9 days later increased serum P4 concentration.…”

“…The use of gonadotropin releasing hormone (GnRH) or the male effect in PGF2α-based protocols was reported previously (Mirzaei et al, 2017;Olivera-Muzante, Gil, Fierro, Menchaca, & Rubianes, 2011). Human chorionic gonadotropin (hCG) and GnRH administrations on the day of mating or post-mating were applied for improving the reproductive performance (conception, lambing, twining rate and litter size) of different breed (Akkaraman, fat tailed, Afshari × Booroola-Merino crossbred, Anatolian Merino) ewes (Ahmadi & Mirzaei, 2016;Ataman, Aköz, Sarıbay, Erdem, & Bucak, 2013;Dursun, 2019;Rostami, Hajizadeh, Shahir, & Aliyari, 2017). A higher plasma P 4 concentrations was reported in post-mating hCG-treated groups in Afshari × Booroola-Merino crossbred ewes by Rostami et al (2017).…”