ChileanJAR

The iniciation fo ovulation was studied with 286 ovaries of Corriedale 5 year old ewes, collected at Punta Arenas abattoir from January 2^nd to February 28^th 1973. During January no ovulations were detected although follicular size indicated the approaching reproductive season. Ovulations were present from February 15^th onwards.
In 1972, at Otway Research Campus, in Magallanes province, from January 25^th to March 15^th, 216 Corriedale adult ewes were alloted to 6 groups of 36 animals each. Every 10 days one of the groups was exposed to entire rams for a 10 days period. The control group was kept isolated from rams.
Induced synchronization of oestrus was obtained, being February 4^th the optimum time for introduction of rams. Where ram induced synchronization of oestrus was good, up to 62% of ewes lambed within one week.
From February 27^th onwards, fertile mating was detected. February 15^th is the most likely time for begining of ovulation.