Hormone guided estrus synchronization using progesterone sponge and PMSG in goats: a cost-effective optimization strategy

Congliang Wang^1,2Xiaoyu Liu^1,2Shutao Shang¹Zhihao Wang¹Xiayu Yun¹Jinwang Liu²Xiaomin Du¹Junjun Zhai¹Fenghong Wang¹Meixia Wang¹Jinlian Hua^2*Haijing ZHU^1*Lei Qu^1*

• ¹Yulin University, Yulin, China
• ²Northwest A&F University, Yangling, China

This study aimed to evaluate the efficacy of estrus synchronization protocols in goats and to identify the most cost-effective regimen for intensive farming. The protocols assessed used progesterone (P4) sponges or controlled internal drug release (CIDR) devices, with supplemented with pregnant mare serum gonadotropin (PMSG) and prostaglandin (PG), for inducing estrus and pregnancy in goats, and to identify the most cost-effective regimen for intensive farming. During both breeding and non-breeding seasons, does were assigned to treatments: Group I (P4 sponge + PMSG), Group II (P4 sponge + PMSG + PG), and Group III (CIDR + PMSG + PG). We measured estrus response after device removal and pregnancy rates after artificial insemination (AI) were evaluated, and analyzed serum hormone dynamics. Additionally, medication costs were calculated for each protocol. For the most effective protocol, we also determined ovulation timing, performed laparoscopic-assisted AI. Estrus onset occurred earlier in Groups II and III than in Group I during both trial seasons. Nevertheless, overall estrus and pregnancy rates did not differ significantly among the groups (P > 0.05), with Group II exhibiting the lowest pregnancy rate. Medication cost per does and per pregnancy were lowest for Group I. Under the Group I protocol, ovulation occurred at 32 h after estrus onset, and laparoscopic-assisted AI yielded a significantly higher pregnancy rate with fresh semen than with chilled semen (P < 0.05). Serum estradiol (E2) concentration at estrus onset was significantly higher in Group I than in Group II (P < 0.05), and luteinizing hormone (LH) levels at estrus onset and ovulation were significantly higher in Groups I and III than in Group II (P < 0.05). Serum P4, LH, and E2 profiles during the estrous cycle followed similar patterns across all groups. In conclusion, there was no significant difference in pregnancy rates between the three estrus synchronization protocols. However, Protocol I demonstrated the lowest per doe and per pregnancy medication costs. Based on cost-effectiveness considerations, the P4 sponge + PMSG protocol is recommended for use in intensive goat production systems.