The effects of floor temperature, supplemental heat and drying at birth on neonatal swine.

The objective was to determine the effects of floor temperature (20 or 30 C), supplemental heat (heat lamp or light bulb) and drying at birth on piglet survival to day 5. Rectal and infrared skin temperatures were taken on 326 piglets for the first 8 hr postpartum. Blood samples were obtained at birth, day 2 and day 5 and analyzed for thyroxine (T4), triiodothyronine (T3) and cortisol by radioimmunoassay. Weight of each pig was recorded at birth and on days 1, 2, and 5. Survival rates were monitored daily. It was postulated that piglets not dried at birth might have increased heat conservation because of vasoconstriction, which may increase the thermostability and survival of the neonate. Supplemental heat was the only treatment that increased rectal temperature after 3 hr postpartum. Skin temperature at 1/2 and 1 hr was increased by drying, and supplemental heat resulted in elevated skin temperatures from 5 to 8 hr postpartum. Plasma cortisol concentrations were elevated at 2 days of age among pigs not given supplemental heat, but no differences were detected at 5 days of age. Plasma T4 concentrations at 5 days of age were lower among male pigs, pigs on the 30 C floor and pigs given supplemental heat. No significant treatment effects were noted in T3 values at day 5. Pig weights and survival rate at 5 days of age were influenced by the interaction of floor temperature and drying pigs at birth. Pigs dried at birth and kept on the 20 C floor were heavier than those on the 30 C floor, whereas those not dried and kept on the 20 C floor weighed less than those on the 30 C floor. The rate of survival was significantly lower among pigs dried at birth and kept on the 20 C floor than among those not dried and on the 30 C floor (80.9 vs 97.2%), while drying had no effect on survival rate among pigs on the 30 C floor (94.5 vs 93.1%).