RESUMEN
Twenty-five newborn pigs were used to evaluate the energy utilization of sow colostrum by pigs maintained for 24 h in respiratory chambers at an environmental temperature of 33 degrees C. Within a litter, five neonatal pigs were obtained before nursing and allotted on the basis of initial body weight (IBW) at 3 h of age to one of the five treatments: killed, fed intragastrically 6, 12, or 18 g of sow colostrum/kg IBW per meal, or fasted. A total of 24 meals at 60-min intervals was provided and pigs were killed 1 h after the last meal. Heat production (HP) was measured by indirect calorimetry and energy retention (ER) was calculated by metabolizable energy (ME)-HP. A balance technique was used to determine nitrogen (N) retention, and comparative slaughter technique (CST) was used to determine fat accretion and glycogen mobilization. The ME intake increased quadratically (P < .01) with the level of colostrum intake. The efficiency of ME for ER was 91 +/- 4%. Nitrogen absorbed was utilized with an efficiency of 89 +/- 3% for N retention, and the estimated energy cost of 1 kcal of protein synthesized was 1.11 +/- .11 kcal. Thermoneutral maintenance ME requirement was low (68.5 kcal.kg avg BW-1 x 24 h-1) because of the low activity of pigs. Fasting heat production (FHP) measured by calorimetry and CST amounted to 56.4 and 60.4 kcal.kg avg BW-1 x 24 h-1, respectively. Estimates of the contribution of glycogen and protein catabolism to FHP were 83.0 and 6.8%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)