The effect of food intake on prolificacy and plasma progesterone concentrations in multiparous sows

Abstract

Eighty crossbred multiparous sows were allocated to one of 4 treatment groups which consisted of 2 levels of food intake in lactation and 2 levels of food intake in very early gestation. HH (High-High) and HL (High-Low) sows were offered 1.8 kg +0.55 kg per piglet suckled per day in lactation (26 days) wheras LH (Low-High) and LL (Low-Low) sows were given 1.8+0.25 kg per piglet per day. HH and LH sows in early pregnancy were offered 3.5 kg per day and HL and LL sows received 1.5 kg per day. For treatments HH,HL,LH and LL; the bodyweight changes from parturition to service were: −10.1, −14.6, −28.4 and −33.6 kg respectively, the P2 backfat changes over the same period were: −1.6, −2.2, − 4.0 and −3.8 mm respectively, the bodyweight changes in early pregnancy were: +9.5, +0.05, +13.7 and +0.01 kg respectively, the P2 changes were +2.1, +0.73, +1.65 and +0.81 mm.and, the mean litter sizes (total born) were: 10.8, 12.0, 11.1 and 12.1 piglets per litter. (NS) There were no significant differences in plasma progesterone concentrations in early pregnancy but there was a significant correlation ( P<0.01) between plasma progesterone concentration on day 20 post coitum and litter size born. ( r=+0.35) The results have demonstrated that different patterns of food intake in either lactation or in early pregnancy have no significant effect on plasma progesterone concentrations in early pregnancy or on the subsequent litter size in multiparous sows.