Follicular dynamics, estrous response and pregnancy rate following GnRH and progesterone priming with or without eCG during non-breeding season in anestrous Beetal goats

• Published in: Small ruminant research Vol. 182; pp. 73 - 77
• Main Authors: Hameed, Nasir, Khan, Muhammad Irfan-ur-Rehman, Ahmad, Waqas, Abbas, Mustansar, Murtaza, Ali, Shahzad, Muhammad, Ahmad, Nasim
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-01-2020
• Subjects: CIDR; Estrous induction; Ovulation; Subtropical; Ultrasonography; Subtropical; CIDR; Ovulation; Estrous induction; Ultrasonography
• ISSN: 0921-4488; 1879-0941
• DOI: 10.1016/j.smallrumres.2019.106026

•GnRH + short-term progesterone priming induced follicular turnover by 66.6 ± 8.1 h.•GnRH induced ovulation in 44% of the goats within 24 h of its administration.•Administration of eCG increased follicular growth, estrous response, ovulation rate, P4 concentration, and pregnancy rate.•GnRH + progesterone priming without eCG had limited impact on the induction of estrus in anestrous goats.
Goats show seasonal reproductive behaviour under subtropical latitude; limiting the scope of the intensive farming system. Therefore, the objective was to evaluate the efficacy of GnRH plus short-term progesterone treatment with or without eCG on reproductive parameters of anestrous Beetal goats during the non-breeding season. We hypothesized that GnRH + short-term progesterone priming will be effective in inducing estrous response in anestrous Beetal goats during the non-breeding season. Anestrous goats (n = 48) were treated with GnRH and CIDR (Day 0), and randomly divided into eCG (400 IU; n = 27) and non-eCG (n = 21) groups on Day 7. All goats were administered PGF2α at the time of CIDR removal on Day 7. After the GnRH administration, eighteen goats were monitored daily for follicular dynamics. Of which 44% goat ovulated and had earlier emergence of new wave (P < 0.05) than non-ovulating goats. Estrous response after CIDR removal was better in eCG than non-eCG treated goats (92.6% vs. 52.4%; P < 0.05). Similarly, onset of estrus was earlier (33.2 ± 2.0 vs. 57 ± 4.2 h; P < 0.05) and the duration of estrus was longer in eCG vs. non-eCG goats (P < 0.05). Pregnancy rate on day 25 post-breeding was better in eCG than non-eCG treated goats i.e., 60 vs. 18.8% (P < 0.05). The plasma progesterone concentration was more (P < 0.05) in eCG than non-eCG treated goats on days 9 and 18 post-breeding. In conclusion, GnRH at the beginning of short-term progesterone treatment with eCG (at CIDR removal) promotes follicular growth, estrous response, ovulation rate, P4 concentration, and pregnancy rate in anestrous goats during the non-breeding season. However, GnRH plus progesterone priming without eCG has a limited impact on the induction of estrus in anestrous goats. Thus, results do not support the initial hypothesis.