Some aspects of feeding of brood gilts and sows

The amounts of feed required during each of the reproductive phases are graphically illustrated and supported by specific recommendations where possible with discussion of the underlying rationale and of the often conflicting considerations. For flushing, an increase of 50 to 100% of energy requirements above maintenance level is recommended, supplied, for example, by one to two kg maize extra per day during the week before expected oestrus, in order to increase the ovulation rate. During pregnancy a constant feeding level is proposed 2.2 to 2.5 kg of feed with 8.8 MJ of nett energy/kg and 12% digestible crude protein being necessary. Two days before farrowing the feeding level must be lowered and steps taken to keep the gut contents to a minimum. During lactation the feed has to contain 8.8 MJ nett energy/kg and 14% digestible crude protein and the intake reduced by 10 to 20% in the case of early weaning. At weaning a fasting regime is suggested to effect physiological stress. The relation between feeding level during pregnancy and the mass gain of the sow asnd number of piglets born, as well as on the birth mass of the piglets, and the relation between N intake and N retention and litter mass oat birth are shown graphically.