T. E. Bond

The effects of modified summer environment on swine behaviour

Abstract Daily observations were made at two-hour intervals over a 50-day period on growing pigs subjected to the following heat relief measures: shade only (controls), wallow in the sun, wallow in the shade, wallow combined with increased air motion, and access to an air-conditioned house. The pigs were maintained in dry lot concrete pens under California summer conditions with an average mean temperature of 75 °F. (average range of 58·5 to 94·4 °F.). Where shade was the only relief measure provided, it was used about 80 per cent, of the time from 7 a.m. until 3 p.m. Addition of a wallow reduced the time spent in the shade. Use of portable houses (3-sided, wooden floor, metal roof) was relatively low as compared to fabric shades and other shade on the concrete floor. Use of heat relief measures increased rapidly when the temperature went above 70 °F. The air-conditioned house was used about 60 per cent, of the time during the hours of observation. An increased weight gain in all treated lots over the control lot was not correlated with any behaviour pattern. The importance of suitable shade on summer days with temperature over 70 °F. is indicated. The use of other relief measures such as wallows also is of importance.

Continuous versus periodic observations in behaviour studies with swine raised in confinement

Abstract A group of 9 hogs in confinement was observed continuously for different activity patterns for 12-hour periods on 5 different days during the summer. Data were analysed for different observation intervals up to 120 minutes and compared with the activity pattern recorded continuously. Depending upon the activity pattern or patterns of interest, observation intervals up to 60 minutes proved adequate. Activities consuming relatively small periods of time required a shorter observation interval. Significant differences among individual animal activity patterns were noted over the five 12-hour periods, emphasizing the shortcomings of observing only one animal per group.

Physiological response of swine to cycling environmental conditions

Rectal and surface temperatures, and respiration and pulse rates, were obtained for groups of Duroc pigs that were exposed to air temperatures that varied sinusoidally over a 24-hour period. Two groups averaging 37 and 108 kg were exposed to a constant temperature of 21·1°C and then to temperatures that cycled about a mean of 21·1°C (15·6–26·7°C, 10·0–32·2°C, and 4·4–37·8°C). For a third group averaging 53 kg, the minimum was always near 21·1°C, and the maximum air temperature of the cycle was 33·2, 42·5 or 48·8°C. The response of rectal and surface temperatures, and pulse and respiration rates, to the various 24-hour cycling air temperatures are discussed and com-pared with inherent daily fluctuations in these responses that are present even when there is no variation in air temperature.