Growth performance and enzyme development in weanling pigs injected with dexamethasone.

Three experiments were conducted to evaluate the effects of dexamethasone (DEX) on growth performance and on selected digestive enzyme activities in weanling pigs. In Exp. 1, 96 pigs (6.7 kg BW and 27 d) were used in a 3 x 2 factorial combination of three DEX frequencies (no injection; 1 mg DEX/kg BW 3 d before weaning; and 1 mg DEX/kg BW 6 and 3 d before weaning) and two feeding regimens: a simple diet fed throughout the 28-d trial, or a semicomplex diet fed during the first 14 d postweaning, followed by the simple diet. Growth performance was not affected (P > .10) by hormonal treatment. Pigs fed the simple diet had a greater ADF1 after d 15 postweaning (P < .10) and higher ADG from 15 to 21 d postweaning (P < .01). In Exp. 2, 80 pigs (7.2 kg BW and 26 d) were assigned 3 d before weaning to four dosages of DEX (0, .33, .66, and .99 mg/kg BW). Growth performance was similar regardless of DEX dosing. In Exp. 3, 24 pigs (6.4 kg BW and 21 d) were injected with DEX (1 mg/kg BW) or saline solution on d 3 before weaning. Four pigs per treatment were slaughtered at weaning, or on d 3 and d 6 postweaning. Dexamethasone resulted in greater (P < .10) pancreas weight and increased (P < .01) total activity of amylase and sucrase, but lactase was lowered (P < .10). Dexamethasone injection enhanced digestive enzyme activity but failed to improve performance, presumably because of the reduced feed intake of pigs at weaning.