Fat changes in breeding sows

Abstract

ABSTRACTOne hundred and eight crossbred sows from nine different commercial sources were monitored over two parities for changes in live weight and fatness. All sows were given a common nutritional regime. Thirty sows were slaughtered and physically dissected. After weaning the second litter, mean carcass measurements ( ± s.d.) were: live weight, 139±9·5kg; lean mass, 26·6 ± 2·8kg; subcutaneous fat mass, 4·l ± l·7kg; ultrasonic P2 backfat depth (USP2), 11·3±2·8mm; total dissected fat (kg) = 0·63 ± 0·073 USP2 —1·1 ±0·85(r = 0·85). Between mating (parity 1) and weaning (parity 2) sows gained 22kg live weight and lost 6·8mm backfat. There were significant differences between sources with respect to fatness, despite standardized feeding. It is suggested that for breeding pigs such as these, starting their reproductive life with limited fat reserves (16·4 ± 3·0mm USP2 at 92 ± 6kg live weight), a conventional fat-exploiting feeding regime is unlikely to be appropriate.