Reproductive traits in primiparous sows in relation to feeding level.

Abstract

To estimate the effect of plane of nutrition and induction of oestrus with 400 IU of pregnant mare serum and 200 IU of human chorion gonadotropin, 113 primiparous Dutch Landrace sows were given 4 or 2.5 kg feed daily from weaning to oestrus. The feed included maize 12, barley 18, soya bean oilmeal 15, wheat bran 15, cassava pellets 13, maize gluten feed 5, lucerne meal 8, citrus pulp 5.5, molasses 5, animal protein 1.1%, minerals and vitamins. The number of sows in oestrus within 21 days of weaning was 69 (61%). Within 7 days of induction of oestrus on day 21, 41 sows were in oestrus (36%). On day 21, 37 (65%) of the better-fed sows were in oestrus and 32 (53%) of the poorer-fed group. The interval from weaning to spontaneous oestrus was 9.1 and 8.2 days, respectively, and ovulation rate 15.2 and 14.8. Size of the sexual organs was not affected by feeding level. Rate of gain of sows during the interval from weaning to oestrus was influenced by feeding level: +4.1 kg and -2.3 kg, respectively, for the sows in oestrus within 21 days of weaning. Sows with induced oestrus shed significantly more ova than did sows in which oestrus was not induced (21.7 and 15.0, respectively). Loss of weight, loss of heart girth, and loss of backfat thickness during previous lactation (absolute and relative) did not differ for sows with or without induction, but was higher for sows with a spontaneous oestrus between 10 and 21 days after weaning than for sows with an oestrus within 10 days after weaning. Ovulation rate was not affected by weight at weaning or at oestrus, weight loss during lactation, gain during the interval from weaning to oestrus or size of the preceeding litter at birth. (Abstract retrieved from CAB Abstracts by CABI’s permission)