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 (31 degreesN lat.). Average daily low temperature and high temperatures and average RH for year 1/year 2 were: 21 degreesC/21 degreesC, 32 C/33 degreesC, and 83%/78% for summer; and 9degreesC/7degreesC, 22 degreesC/21 degreesC 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.