Three trials involving 118 sows were conducted to evaluate the effects of fat and triamcinolone additions in the diets of late-term gravid sows on pre- and postweaning performance of pigs. Beginning an average of 9 d prepartum, sows were fed daily 1.8 kg of a fortified, corn-soybean meal diet [6 Mcal of metabolizable energy (ME) and 290 g of protein/sow] that was supplemented with 4 Mcal of ME/sow in the form of starch, soybean oil or soybean oil plus 70 mg/sow of triamcinolone, a synthetic glucocorticoid. During a 28-d lactation, sows were self-fed a standard 14% protein, corn-soybean meal diet. The addition of soybean oil to the diet of sows during late gestation did not (P greater than .10) influence the weights of survivability of pigs at birth, 14 or 28 d of age, but increased (P less than .05) the carcass fat content of the pigs at birth. The dietary addition of triamcinolone to the sow's prepartum diet increased (P less than .10) pig weights at birth and 14 d, and tended to increase pig weights at 28 d compared with those of pigs from sows fed soybean oil only. Prepartal administration of triamcinolone depressed (P less than .05) carcass protein content and adrenal weights in pigs at birth or 28 d of age. From weaning (d 28) to 56 d of age, pigs from sows fed soybean oil before parturition, particularly those from sows fed triamcinolone, tended to consume less feed and gained slower and less efficiently than pigs from sows fed starch, although the differences were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)