Effect of environmental temperature and dietary energy concentration on the performance and carcass characteristics of growing-finishing pigs fed to equal rate of gain

Abstract

An experiment involving 54 individually-housed castrated male pigs was conducted to determine the interactive effects of environmental temperature (12, 20 or 28°C) and dietary-energy density (13.0 vs. 15.0 MJ digestible energy (DE) kg −1) on the performance and carcass characteristics of growing-finishing pigs, fed to achieve equal rate of weight gain at any treatment. The diets were based either on maize with supplemental maize oil (high-energy diet), or on barley with supplemental wheat bran (low-energy diet). There was no temperature × dietary-energy density interaction ( P > 0.10) for any parameter studied. Daily DE intake, and the amount of DE required per unit of body weight gain (BWG) or empty body weight gain (EBWG), increased quadratically ( P < 0.01) as environmental temperatures decreased. Additional DE required to compensate for 1°C drop in temperature between 28 and 20°C, and between 20 and 12°C, amounted to 0.20 and 0.44 MJ day −1, respectively. The environmental temperature had no substantial effect on the total fat of the carcass. However, the body fat distribution was modified: backfat weight and thickness were increased ( P < 0.05) in the cold, whereas weight of leaf fat was decreased ( P < 0.05). The decrease in temperature was associated with a linear increase ( P < 0.01) in the backfat unsaturation rate.