|Gaines, Aaron - UNIV OF MISSOURI|
|Allee, Gary - UNIV OF MISSOURI|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 12, 2003
Publication Date: N/A
Interpretive Summary: A series of experiments were conducted on commercial swine farms to determine if the beneficial growth responses we have previously reported for small-scale studies would be similar under commercial conditions. Three separate experiments were conducted on three different commercial farms. We evaluated two synthetic glucocorticoid products, dexamethasone and isoflupredone, on a total of 1,321 pigs in these three experiments. We also evaluated the potential benefit of supplying supplemental milk to glucocorticoid-treated pigs. Our results indicated, contrary to our previous findings, that supplying exogenous glucocorticoids to neonatal pigs shortly after birth did not enhance growth during the preweaning period. However, the experiments did highlight the importance of parity, environmental conditions, and health status on the pig¿s growth response to exogenous glucocorticoids. Overall, results from the present study, combined with our previously reported studies, would indicate that the beneficial growth effect associated with exogenous glucocorticoid treatment may be practical in some commercial situations, but not all. This information will be of interest to swine producers, swine veterinarians, scientists, and extension personnel.
Technical Abstract: Three commercial trials were conducted evaluating the use of dexamethasone (Dex) and or isoflupredone (Predef) in improving preweaning growth performance of neonatal pigs. The objectives of the commercial trials were three-fold: to evaluate Predef as compared to Dex; address the sexual dimorphic growth response observed in a previous commercial trial; and to determine whether there is any benefit to providing Dex-treated pigs supplemental milk. In Exp. 1, 276 pigs (Triumph 4 x PIC Camborough 22) were assigned according to birth weight and sex to three treatments. Treatments included either saline (Control), Dex (2 mg/kg BW i.m. injection of dexamethasone) or Predef (2 mg/kg BW i.m. injection of Predef 2 X) within 24 hours after birth. A treatment effect was observed for BW at weaning (P < 0.003) with pigs injected with Predef being 0.51 kg lighter than Control and Dex treated pigs. The lower body weights of Predef treated pigs at weaning were due to a lower ADG (P < 0.001) during the preweaning period as compared to Control and Dex pigs. The ADGs of Predef, Control, and Dex pigs were 170.1 +/- 5.9, 200.7 +/- 5.9, and 202.0 +/- 5.7 g/d, respectively. In Exp. 2, 703 pigs (Triumph 4 x PIC Camborough 22) were assigned according to birth weight and sex to three treatments. Treatments included either an i.m. injection of saline (Control), Dex1 (1 mg/kg BW of Dex), or Dex2 (2 mg/kg BW of Dex) within 24 hours after birth. No treatment effects were observed for BW at weaning (P > 0.76) or ADG (P > 0.62). The ADGs of Control-, Dex1-, and Dex2-treated pigs were 230.6 +/- 3.75, 225.8 +/- 3.86, and 226.4 +/- 3.82 g/d, respectively. In Exp. 3, 342 pigs (Genetiporc) were assigned to two treatments according to birth weight and sex. Treatments included either an i.m. injection of saline or Dex (2 mg/kg BW) within 24 hours after birth. All pigs were provided supplemental milk from the time of treatment until weaning age. No treatment effects were observed for BW at weaning (P > 0.19) or ADG (P > 0.13). The ADG of Control and Dex treated pigs were 229.4 +/- 5.28 and 218.1 +/- 5.15 g/d, respectively. The negative response to Predef was similar to the growth suppressive effects observed with chronic glucocorticoid treatment. In contrast to our previous findings, Dex did not improve preweaning growth performance regardless of dosage or supplemental milk.