Effect of boar contact on follicular development and on estrus expression after weaning in primiparous sows. Langendijk,P.; Brand, H. van den; Soede, N, M.; Kemp, B. Theriogenology (2000) 54(8) 1295-1303.
Boar contact can induce ovarian activity, advance oestrus and stimulate oestrous behaviour in sows. High amounts of boar contact can however, suppress oestrous behaviour. The present study with primiparous sows was designed to compared sows (n = 47) that had contact with a teaser boar during detection of oestrus with sows (n= 47) that had no boar contact at all [Netherlands, date not given]. Number of sows detected in oestrus within 9 days after weaning, onset and duration of oestrus, follicular dynamics and timing of ovulation were studied. Boar contact increased the number of sows that ovulated and showed oestrus from 14 of 47 to 24 of 47 (p<0.05). Average timing of ovulation was later for sows with boar contact (165 h. vs 150 h. after weaning). Duration of oestrus, detected without a boar was similar in the two groups. For the sows with boar contact, duration of oestrus detected with a boar was longer than oestrus detected without a boar (56 vs. 38 h: p<0.01). Follicular dynamics were not affected by boar contact; boar contact only increased the number of sows with ovulation. Ovulatory sows showed a larger increase in follicular diameter (p<0.01) from weaning to day 4 after weaning (from 2.3 to 5.4 mm) than anovulatory sows (from 2.5 to 4 mm). Anovulatory sows did not show follicular growth after day 4. It is concluded that boar contact can increase the number of sows that ovulate and show oestrus after weaning. Oestrous behaviour does not seem to be suppressed by contact with a teaser boar compared to sows without boar contact. Copyright CAB International
