EFFECT OF SEASON (SUMMER VS. FALL) AND DIET NUTRIENT DENSITY ON PERFORMANCE AND CARCASS CHARACTERISTICS OF GROWING–FINISHING SWINE

摘要

A study was conducted to evaluate the effects of rearing environment/season (hot, humid/summer vs. thermoneutral/fall) and dietary nutrient density (high energy/high lysine vs. moderate) on performance and carcass lean content of growing-finishing swine (32 to 112 kg). For each of two consecutive years, two trials, each with 80 pigs, were conducted: one during the summer, and the other during the fall. The trials were conducted in northwest Florida (31º N lat.). Average daily low temperature and high temperatures and average RH for year 1/year 2 were: 21ºC/21ºC, 32ºC/33ºC, and 83%/78% for summer; and 9ºC/7ºC, 22ºC/21ºC, and 79%/76% for fall. Diets were corn and soybean meal based. The high energy/high lysine diets (H) were additionally supplemented with L-lysine HCl (at 0.15% of the diet) and feed fat (at 6%). The H and moderate (M) diets averaged 3.6 and 3.3 mcal ME/kg, respectively. Ten pigs were allotted to each pen and assigned to one of two dietary treatments. Pigs were housed in a curtain-sided building in pens with solid concrete floors. Pigs had access to water for evaporative cooling. Floor space was 0.72 m 2 per pig