The effect of pregnancy, energy intake and mating weight on protein deposition and energy retention of female pigs

Abstract

SUMMARY: 1. In a comparative slaughter experiment, 12 female pigs (six at 80 kg and six at 100 kg) were allocated at first oestrus to each of five treatments: Treatment 1 initial slaughter, or Treatments 2, 3 and 4 mated and given 19·5, 25·8 or 32·1 MJ ME/day for the last 100 days of pregnancy, or Treatment 5 not mated (virgin) and given 25·8 MJ ME/day over a similar period. Pigs on Treatments 2, 3, 4 and 5 were given the same amount of protein and were killed about 123 days after first oestrus. Piglets were removed at birth.2. Total protein deposition (carcass+viscera+piglets) was increased from a total (±SE) of 5·50 to 8·47 (±0·43) kg as ME intake was increased from 19·5 to 32·1 MJ ME/day. About 75% of the increase in protein deposition was in the carcass component. The average response to ME was 2·2 ± 0·58 g total protein deposition per MJ increment in ME.3. The once-mated pigs deposited similar amounts of total protein to the virgin pigs but significantly less (P0·85. day. The average efficiency of utilization of ME for energy retention was 58·5 ± 6·2%.6. There was no evidence of any pregnancy anabolism other than that involving the conceptus, the needs of the dam specific to pregnancy and preparation for lactation.