We have tried to join in this paper most of the actually available information about reproduction in the main sheep breeds of Portugal, namely Merinos, Bordaleiros and Churros. Most f1ocks are naturally bred all over the year, but in some of them the mating season is from spring to autumn. Ovarian cyclicity is maximum from September to January and minimun in May. Puberty is reported to start between 6 and 12 after birth, depending on the breed and the season of birth. Fertility (ewes lambing in the year) is about 80‑90% and prolificacy varies from 113‑116% (Merino and Churro) and 132‑135% (Bordaleiro). Hormonal treatments (progestagen, melatonin) to improve reproductive performance have been only used in experimental work.
Seasonality is not very marked and its effects can be overcome by improvement of management techniques, mainly nutrition that seems to be the most important factor influencing reproductive performance.