Reproductive responsesand progesterone levelsof postpartum oestrussynchronization in goatswith different body reserves

摘要

Thirty adult goats were classified at parturitioninto two body condition score (BCS)groups: BCI (n=16) with a score of 2.7 and BCII(n=14) with a score of 2.0. On the fiftieth daypostpartum, oestrus was synchronized by CIDRfor 5 days. Upon CIDR removal (Day 0), theyreceived 1 mL of PGF2α IM and mated for 72hours. Kids were kept with does and weaned at40 days of age. Blood samples were taken at 0,1, 4, 8 and 21 days after CIDR removal for progesteroneassay. The BCI group showed a greaterweight loss compared to the BCII group, andBCS before synchronization was 1.9±0.08 and1.6±0.07 for the BCI and BCII groups, respectively(P<0.05). The weaning weight of BCI kidswas greater when compared to BCII (P<0.001).After CIDR removal, all females were markedand mated. Pregnancy rate was higher in BCIgoats (87% vs 36%; P<0.05), as well as prolificacy(1.65 vs 1.25; P<0.05) and twinning rate(0.62 vs 0.25; P<0.05). Progesterone concentrationwas higher in pregnant does in BCI. A positiverelationship was found between progesteronelevel at CIDR removal and BCS at parturition(0.57; P<0.01), also between progesteronelevel at 21 days after CIDR removal andBCS at parturition (0.47; P<0.05), or BCSbefore synchronization (0.51; P<0.05). We concludethat oestrus response to postpartum CIDRsynchronization appeared to be slightly dependenton BCS. However, goats with low BCS atoestrus synchronization exhibited a reductionin pregnancy rate.