The Catalonian donkey breed is in danger of extinction, and much needs to be learned about the reproductive features of its females if breeding and conservation programmes are to be successful. This study reports the oestrous behaviour, oestrus cycle characteristics and dynamic ovarian events witnessed during 50 oestrous cycles (involving 106 ovulations) in 10 Catalonian jennies between March 2...

During the oestrous cycle of the sheep, normal regression of the corpus luteum (cl) on Day 15 is prevented by total hysterectomy and the cycle is extended to a length approximating the gestation period (Wiltbank & Casida, 1956; Moor & Rowson, 1964). Rowson & Moor (1964) also reported that the increased life-span of the cl in partially hysterectomized sheep was roughly proportional to the amount...

Deslorelin acetate implants, recently licensed in Ireland and the UK for ovulation induction in mares, have been associated with prolonged interovulatory intervals in USA studies, leading to the practice of removing implants postovulation. Trial data in Australia indicate a less pronounced effect on interovulatory intervals, suggesting possible geographical variation. Objectives of the current ...

The expression of oestrous behaviour in Holstein Friesian dairy cows has progressively decreased over the past 50 years. Reduced oestrus expression is one of the factors contributing to the current suboptimal reproductive efficiency in dairy farming. Variation between and within cows in the expression of oestrous behaviour is associated with variation in peripheral blood oestradiol concentratio...

Hormone patterns in blood plasma were examined in relation to the bovine oestrous cycle in two experiments. During the luteal phase LH pulse frequency was low (2-3 pulses per 8 h). There were no consistent correlations between LH, FSH and progesterone concentrations. During luteolysis, falling progesterone concentrations were accompanied by an increase in oestradiol-17 beta concentrations, LH c...