GROWTH AND BODY CONDITION OF SOWS GIVEN DIFFERENT FEEDING REGIMES DURING THE REARING STAGE AND THROUGH 8 PARITIES WHEN HOUSED IN GROUPS WITH STRAW BEDDING

A 2 X 3 factorial experiment was designed to study the consequences of feeding strategy during rearing and pregnancy over eight parities on sow growth and body condition. Two hundred and fifty-four gilts were g roup-fed on a restricted scale rising to either 2.25 (L) or 2.70 (H) k g/day (12.5 MJ/kg digestible energy (DE), 193 g/kg crude protein (CP) diet) from 70 to 175 days of age. A total of 156 of the L and H gilts were then given either 1.8 (1), 2.1 (m) or 2.4 (h) kg/day during subse quent pregnancies (12.9 MJ/kg DE; 177 g/kg CP diet). The same diet was offered to a standard scale during lactation. Sows were group-housed in pregnancy and given straw bedding. Losses of sows in rearing and ea ch parity were not associated with treatment. After rearing, data have been presented only for those sows which completed eight parities. At 175 days of age, H gilts had grown faster (P < 0.001). From 175 days to service all gilts were given the same feeding regime but L gilts pu t on significantly more weight than H gilts, exhibiting more efficient utilization of food. There were no statistically significant differen ces in weights between L and H sows after the third pregnancy but L so ws gained more weight than H sows in most pregnancies. The sows grew i n each parity, indicating mature body size was not achieved. The pregn ancy regimes had a significant (P < 0.05) effect on live weight, P2 ba ckfat measurement, body length, neck circumference and condition score . Pregnancy treatment h produced the heavier and fatter animals but no t all treatment 1 sows maintained adequate backfat levels for six pari ties. When housed in groups and given a generous supply of straw, the nutritional requirements of sows to sustain growth and body condition suitable for a long life may be less than has been previously identifi ed for sows housed on concrete and slats without bedding.