Influence of temperature and light on feeding behaviour of pigs

Abstract

Feeding behaviour and feed consumption of growing pigs (36 kg) were observed over a 6-day period while they were in two chambers, each housing four pigs. The temperature in one chamber was held constant at 33°C while the other cycled between a minimum of 26°C at 0530 h and a maximum of 40°C at 1400 h. The light schedule was 16 h light (0500–2100 h) and 8 h dark. Water and feed were provided ad libitum. Each chamber had one feeder capable of accommodating three pigs. Feeding behaviour was monitored continuously on a video recorder while feed consumption was determined every 4 min from an electronic output from a feeder scale. Feed consumption and feeder usage in both treatments were primarily a response to the light: dark pattern with two peaks in food intake; one at about the time the lights were turned on and the other shortly before the lights were turned off. Cyclic temperatures resulted in similar daily feed intakes and feeder usage, but shifted the diurnal feeding pattern. Feed consumption shifted to the coolest part of the thermal cycle, and the period of highest feed intake occurred earlier in the morning and later at night than those in the constant temperature treatment. The feeder was occupied for only 22 and 23% of the time in the constant and cyclic temperature treatment, respectively. During peak feeding activity, feeders were utilized by only one pig ∼50% of the time. Social facilitation did not appear to influence feeder usage. Only 25% of total feeding time occurred with two or three pigs at the feeder. During the remaining time, feeder usage was on an individual animal basis. During periods of peak feeder usage, 30% of the feeder usage was by two or three pigs at one time in the constant temperature treatment, while 40% of the feeder usage was by two or three pigs in the cyclic temperature treatment. Rate of ingestion (defined as feed consumed in g min −1 a pig was at the feeder) indicated that for 74% of the time the pigs in both temperature treatments consumed feed at a rate <25 g min −1 per pig. Mean ingestion rates for both thermal treatments were similar (15 g min −1 per pig).