Growth rate and protein and fat gain in early-weaned piglets housed below thermoneutrality

Abstract

Two trials involving 78 piglets were conducted over a period of six weeks, following weaning at approximately three weeks of age, in order to determine the effect of cold temperatures on growth depression and on the protein ( N × 6.25) (P) and fat (F) deposition in individually-housed piglets. The temperature patterns and mean daily food intakes were 32-26, 28-22, 24-18°C and 81 g/kg 0.75 (Trial I); 28-22°C and 73 and 62 g/kg 0.75, 24-18°C and 100 and 74.5 g/kg 0.75 (Trial II). Depositions of protein and fat were determined by the comparative slaughter technique. Growth rate increased with each unit of daily food intake (1 g/kg 0.75) by 7.67 ± 0.72 g/day. This value did not vary significantly with temperature. At a constant level of food intake of 80 g/kg 0.75/day, the growth rate of piglets and the gain: food ratio were similar in the 32-26 and 28-22°C environments and significantly higher than at 24-18°C. Growth rate decreased on average by 12.2 g per 1°C fall in temperature below 28-22°C. Daily P and F were increased by 0.98 ± 0.10 and 1.24 ± 0.10 g/day per unit increment in food intake, respectively. These regression coefficients did not vary significantly with temperature. At a constant level of food intake, P and F decreased by 1.30 and 1.35 g/day per 1°C fall in temperature below 28-22°C, respectively. The protein content of the empty body weight gain increased with each decrease in daily food intake by 0.09 ± 0.02% and the fat content fell correspondingly by 0.23 ± 0.03%. These regression coefficients did not vary significantly with temperature.