Observations on the reproductive performance of ewe lambs synchronised for oestrus.

Oestrus induction and synchronisation achieved by means of progesterone implants (Silestrus; Abbott) and one or two injections of 500 in FSH (Gestyl; Organon) at 15-day intervals was followed by natural service in 194 10-month-old ewe lambs, fed on pasture (Group A, of 101 animals) or pasture and concentrates (Group B, of 93 animals) used to study the influence of nutrition and of induction of a second synchronised oestrus on the percentage of oestrus manifestations, conception rate, number of lambings and of lambs born among the above animals.