Published online by Cambridge University Press: 02 September 2010
Fresh sperm motility declined from 79·2 (s.e. 0·9)% to 55·8 (s.e. 1·7)% while occurrence of normal acrosomes declined from 82·9 (s.e. 1·3)% to 71·3 (s.e. 1·2) % from the day of collection to 7 days after collection, and conception rate declined from 47·6% using 3-day-old semen to less than 30% from using 5· or 7-day-old semen. Neither the number of embryos nor embryo survival from pregnant sows were affected by the age of semen. Boar effects were evident but they did not interact with the effects of age of semen, indicating that semen quality after storage was proportional to initial semen quality.