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Title: PRE- AND POSTWEANING PERFORMANCE OF PIGS INJECTED WITH DEXAMETHASONE AT BIRTH

Author
item GAINES, A - UNIVERSITY OF MISSOURI
item Carroll, Jeffery - Jeff Carroll
item ALLEE, G - UNIVERSITY OF MISSOURI
item YI, G - UNIVERSITY OF MISSOURI

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/10/2002
Publication Date: N/A
Citation: N/A

Interpretive Summary: We conducted a study to determine pre- and postweaning performance of pigs injected with a synthetic stress-mimicking hormone (dexamethasone; Dex) either 1 or 24 h after birth. The study was split into 3 experiments: 1) preweaning period; 2) nursery period; and 3) grow/finish period. At the end of the preweaning period, Dex-treated males were 10% heavier than Control males, and there was no difference in body weight among the female groups. At the end of the nursery period, Dex-treated males were on average 8% heavier than Control males, and there was no difference in body weight among the females. We also did not detect any difference in feed efficiency among the groups during the nursery period. At the end of the grow/finish period, Dex-treated males were on average 5.45 kg heavier than Control males, and there was no difference in body weights among the females. At the end of the study, we did not detect any treatment differences in carcass characteristics or quality due to treatment. These studies demonstrate that Dex given within 24 h of birth improves both pre- and postweaning performance of male, but not female pigs. This information is extremely important and relevant to swine producers, swine veterinarians, scientists, and industry personnel as it has the potential to enhance economic returns in swine production.

Technical Abstract: A trial was conducted to determine pre- and postweaning performance of pigs injected with dexamethasone (Dex) either 1 or 24 h after birth. In Exp1, 225 pigs were assigned according to birth weight and sex to 3 treatments. Treatments (Trt) included either saline (Cont), Dex1 (2 mg/kg BW i.m. injection of Dex within 1 h of birth) or Dex24 (2 mg/kg BW i.m. injection of Dex within 24 h after birth). Birth weights did not differ among Trt (P>0.96) or between sexes (P>0.70). For body weight at weaning (15 d), there was a Trt x Sex interaction (P<0.02) with Dex1 and Dex24 males 10% heavier than Cont males and no significant differences in BW among the female groups. In Exp2, 180 pigs from Exp1 were transported to a SEW nursery facility and assigned to 10 pens/Trt/Sex (60 pens). At the end of Exp2 (49-d period) there was a Trt x Sex interaction (P<0.01) for BW with Dex1 and Dex24 barrows being an average 8% heavier than the Cont barrows and no signficant difference in BW among the gilts. No differences in fee efficiency (G:F) were observed during the nursery period. In Exp3, pigs from the nursery were moved to a finishing facility and assigned to 4 pens/Trt/Sex (24 pens). Real-time ultrasound was used to measure 10th rib backfat depth (BF) and loin-eye area (LEA). At the end of Exp3 (83-d period) there was a Trt x Sex interaction (P<0.02) for final BW with Dex1 and Dex24 barrows being on average 5.45 kg heavier than Cont barrows and no difference in BW among the gilts. No significant treatment differences were observed for BF, LEA or G:F. These studies demonstrate that Dex given within 24 h of birth improves both pre- and postweaning performance of barrows but not gilts.