Abstract:

The response to the male effect was studied in two Saˆanen and two Alpine flocks over 5 consecutive years. Adult male and female goats were exposed to artificial long days (16 h light and 8 h darkness, 16L:8D) in open barns for approximately 3 months (between December 1 and April 15) followed by a natural photoperiod.

Goats were treated for 11 days with fluorogestone acetate (FGA) or progesterone (CIDR) immediately before joining. Bucks carrying marking harnesses with adapted aprons joined females 49-63 days after the end of the long-day treatment (between April 30 and June 5) and were left with them for 5 days. In experiment 1 (n = 142), FGA- and CIDR-treated goats were inseminated at a time based on the detection of oestrus.

Two insemination groups were distinguished by the occurrence of marking over a 48-h period. Earlier (group 1) and later (group 2) buck-marked goats received one single insemination 12-24 h or 0-12 h after marking, respectively. Unmarked goats were inseminated along with group 2. In experiment 2 (n = 344), FGA-treated goats were inseminated 52 and 70 h (52 h:70 h group) or 52 and 75 h (52 h:75 h group) after joining. In experiment 3 (n = 285), FGA-treated goats were inseminated 52 h (1-AI group) or 52 and 75 h.