Two reduced nocturnal temperature regimens for early-weaned pigs

Two experiments, each consisting of three trials and using 3- to 4-wk-old newly weaned pigs, were conducted to evaluate the effects of two reduced nocturnal temperature regimens on weaned pig and subsequent growing-finishing performance and nursery energy (propane and electricity) use. In Exp. 1, nursery treatments were 1) a control temperature (CT) regimen of 30 degrees C constant air temperature lowered 2C degrees/wk and 2) a regimen for pigs in pens with hovers (MRNT-H) in which the temperature from 1900 to 0700 beginning 1 wk after weaning was lowered 6 C degrees from the 0700 to 1900 temperature setting, which was 3C degrees lower than CT. The nursery temperature treatments in Exp. 2 were 1) CT and 2) a 10C degrees reduction in air temperature (MRNT10) from 1900 to 0700 from CT beginning 1 wk after weaning. In addition, within each temperature, diet sequences of 1.2% lysine for 3 wk followed by 1.0% lysine vs 1.15% lysine offered continuously were evaluated. In Exp. 1, there was no effect (P greater than .1) of temperature on feed intake but ADG decreased (P less than .001) in two of the three trials for MRNT-H vs CT and feed/gain worsened (P less than .05) in all trials. In Exp. 2, there was no difference between MRNT10 and CT for ADG and feed/gain. No interaction was observed between nursery diet and temperature regimen for weaned pig performance. There was no effect (P greater than .1) in either experiment of nursery temperature on subsequent growing-finishing performance. Overall energy savings comparing the MRNT-H and CT treatments were 68 MJ per weaned pig. Energy savings for Exp. 2 were 79 MJ per weaned pig. Application of cyclical temperatures in a controlled manner can result in energy savings of approximately $50 per pig weaned under the conditions of these experiments.