Effect of lactation length of the sow on plasma progesterone, oestradiol 17-β and embryonic survival

Abstract

ABSTRACTThirty-three Landrace × Large White multiparous sows were allocated randomly to one of three treatment groups, and were weaned after a 10-day (treatment A), 21-day (treatment B) or 42-day lactation (treatment C). All sows were bled regularly from weaning through to day 24 post coitum, at which time the sows were slaughtered and their reproductive tracts recovered and dissected.Ovulation rates were similar for all groups. Embryo survival for treatments A, B and C respectively was 0·638, 0·728 and 0·777 but this difference was not significant. Oestradiol 17-β concentrations were significantly higher in sows weaned after 10-day lactations throughout the whole period from weaning to day 10 post coitum compared with the other two treatment groups (P < 0·001).