Anomalies in ovarian function of peulh ewes

The ovarian activity of 8 Niger Peulh ewes was followed for 2 1 2 years by assaying the levels of progesterone in blood plasma sampled daily and by endoscopic observation. Although the ewes did not experience seasonal anestrus, their cycles were not regular. Most animals had persistent corpora lutea at some stage, but particularly in June. This resulted in cycles averaging 49.9+/-6.8 days in length instead of the normal 16.9+/-0.1 days. Intervals between successive luteal phases lasted 4-15 days as compared with 2.3+/-0.06 days seen in normal cycles. This occurred in most ewes at least once during the period from December to April. In these cases, the preovulatory discharge of LH was delayed until 7.5+/-1.8 days after the fall in the level of progesterone. The incidence of these anomalies suggests that the ewes had 69% of the ovulations and 56% of the behavioral estrus as compared to ewes that cycled regularly.