Dwyer C M, Dingwall W S, Lawrence A B
Animal Biology Division, SAC, Edinburgh, UK.
Physiol Behav. 1999 Sep;67(3):443-54. doi: 10.1016/s0031-9384(99)00089-x.
The onset of maternal behaviour in sheep is controlled by levels of oestrogen and progesterone in gestation and the release of oxytocin during delivery. Factor analysis was used to investigate the relationships between maternal behaviour, offspring behaviour, and maternal ovarian hormone levels during gestation in sheep. Ewes gave birth to lambs following embryo transfer between two breeds (Suffolk and Scottish Blackface), which differ in their expression of maternal behaviour. Plasma oestradiol-17beta concentration was significantly higher in Blackface ewes in the last 6 weeks of pregnancy, whereas plasma progesterone was higher in Suffolk ewes in early and mid gestation. Factor analysis revealed three factors that accounted for 50% of the total variation between variables. Factor 1 described lamb activity and had positive loadings for lamb behavioural latencies immediately postpartum, and negative loadings for sucking frequency. Factor 2 described some aspects of ewe maternal behaviour, and had positive loadings for ewe-lamb separation and lamb vocalisation, and negative loadings for ewe grooming behaviour and plasma oestradiol concentration. Factor 3 described ewe and lamb-sucking interactions, and had positive loadings for ewe moving as the lamb made sucking attempts, and negative loadings for ewe and lamb vocalisation. Factor 1 scores were significantly affected by lamb breed: Suffolk lambs received positive scores, indicating a longer latency to right and stand, whereas Blackface lambs had negative scores. Maternal progesterone concentration was significantly correlated with Factor 1 scores. Factor 2 and 3 scores were significantly affected by ewe breed. This study has shown that there are two behavioural axes to maternal behaviour in sheep, and that maternal oestradiol concentration is related to affiliative behaviours (e.g., grooming) but only weakly to ewe responsiveness to lamb-sucking attempts.
绵羊母性行为的起始受孕期雌激素和孕酮水平以及分娩时催产素释放的控制。采用因子分析来研究绵羊孕期母性行为、后代行为和母羊卵巢激素水平之间的关系。母羊在两个品种（萨福克和苏格兰黑脸羊）之间进行胚胎移植后产羔，这两个品种在母性行为的表现上存在差异。在怀孕的最后6周，黑脸母羊的血浆雌二醇-17β浓度显著更高，而在妊娠早期和中期，萨福克母羊的血浆孕酮更高。因子分析揭示了三个因子，它们占变量间总变异的50%。因子1描述羔羊活动，对产后即刻羔羊行为潜伏期有正负荷，对吸吮频率有负负荷。因子2描述母羊母性行为的某些方面，对母羊与羔羊分离和羔羊鸣叫有正负荷，对母羊梳理行为和血浆雌二醇浓度有负负荷。因子3描述母羊与羔羊的吸吮互动，对羔羊吸吮尝试时母羊移动有正负荷，对母羊和羔羊鸣叫有负负荷。因子1得分受羔羊品种的显著影响：萨福克羔羊得正分，表明起身和站立的潜伏期更长，而黑脸羔羊得负分。母羊孕酮浓度与因子1得分显著相关。因子2和3得分受母羊品种的显著影响。本研究表明，绵羊的母性行为存在两个行为轴，并且母羊雌二醇浓度与亲和行为（如梳理）有关，但与母羊对羔羊吸吮尝试的反应性仅存在微弱关联。
