Heat occurrence and length in gilts and sows
Nogueira, L.A.G.; Filho, J.M.S.; Neto, A.M.; Silva, M.I.F.; Bergmann, J.A.G.
Proceedings of the 8th International Pig Veterinary Society Congress, Ghent, Belgium, Aug 27-31, 1984: 302
75 Landrace and Large White sows were housed in groups of 5 after a 21-day lactation. From 2 days after weaning, a boar was put in sight of the sows 3 times daily (at 06.00, 12.00 and 18.00 h), and the sows were tested for the standing reflex. The onset of oestrus was considered as the mean interval between the previous observation period and the period in which the standing reflex was first shown. The same procedure was applied to 25 gilts.