GROWTH AND REPRODUCTIVE PERFORMANCE OF GILTS RAISED UNDER SUPPLEMENTARY INFRARED OR MICROWAVE HEAT

Abstract

Forty-eight newly weaned gilts with an average weight of 7.34 kg were randomly allocated in groups of four to either continuous infrared (CI), operant infrared (OI) or operant microwaves (OM) for 12 or 13 d. There was no significant difference (P > 0.05) between treatments for average total weight gain or average feed:gain. Pigs allowed OM demanded heat less often (P < 0.05) than the OI pigs (6.50 min h−1 vs. 14.56 min h−1, respectively). All pigs were then raised under normal conditions until puberty and bred. Various reproductive parameters were studied. There was no significant difference (P > 0.05) between treatments for the age of the gilts at first breeding. However, the gilts raised under OM were significantly (P < 0.05) older at time of farrowing than the gilts raised under CI. More of the OM gilts required a second service. There was no significant difference (P > 0.05) between gilts raised under OM vs. OI, nor between gilts raised under OI vs. CI for age at farrowing. There was a significant difference (P < 0.05) between replicates for age at first breeding and age at farrowing. There was no significant difference (P > 0.05) between treatments or replicates for average number of piglets born alive (overall group mean: 8.5 piglets, ± 2.57), live vs. dead piglets, males vs. females, or average 21-d piglet weights (overall group mean: 5.47 kg, ± 1.00). Key words: Operant conditioning, gilts, microwave, reproduction