Ractopamine hydrochloride improves growth performance and carcass composition in immunocastrated boars, intact boars, and gilts

Rikard-Bell, C., Curtis, M. A., van Barneveld, R. J., Mullan, B. P., Edwards, A. C., Gannon, N. J., Henman, D. J., Hughes, P. E. and Dunshea, F. R. (2009) Ractopamine hydrochloride improves growth performance and carcass composition in immunocastrated boars, intact boars, and gilts. Journal of Animal Science, 87 11: 3536-3543. doi:10.2527/jas.2009-2002


Author Rikard-Bell, C.
Curtis, M. A.
van Barneveld, R. J.
Mullan, B. P.
Edwards, A. C.
Gannon, N. J.
Henman, D. J.
Hughes, P. E.
Dunshea, F. R.
Title Ractopamine hydrochloride improves growth performance and carcass composition in immunocastrated boars, intact boars, and gilts
Journal name Journal of Animal Science   Check publisher's open access policy
ISSN 0021-8812
Publication date 2009-11-01
Sub-type Article (original research)
DOI 10.2527/jas.2009-2002
Volume 87
Issue 11
Start page 3536
End page 3543
Total pages 8
Editor Lawrence P Reynolds
Jean Rice
Place of publication United States
Publisher American Society of Animal Science
Language eng
Subject C1
830308 Pigs
070202 Animal Growth and Development
Formatted abstract
The β-agonist ractopamine is a dietary ingredient that improves growth and increases the lean mass with little change in fat mass in gilts and barrows. Limited data in boars indicate that dietary ractopamine may increase lean tissue and decrease fat deposition, whereas there are no data for immunocastrated boars. The aims of this investigation were 1) to assess whether the growth performance of all sexes could be maintained over 31 d by using a step-up dietary ractopamine feeding program of 5 mg/kg of ractopamine for the first 14 d, then increasing the dose to 10 mg/kg for a further 17 d, and 2) to determine if dietary ractopamine would increase lean mass in all sexes and decrease fat mass in boars and immunocastrated boars. The study involved 286 pigs randomized and proportionally allocated by breed into 24 groups of 11 or 12 pigs at 17 wk of age, with equal groups of boars, immunocastrated boars, and gilts. Dietary ractopamine decreased (P = 0.005) ADFI during the first 2 wk, particularly in the intact and immunocastrated boars, with the reduction in ADFI being
maintained in the immunocastrated boars after the increment in dietary ractopamine. Daily BW gain was not altered by dietary ractopamine during the first 2 wk, but was increased (P < 0.001) after the increment in dietary ractopamine. Dietary ractopamine decreased (P ≤ 0.033) feed conversion ratio in all sexes with the response being greater after the increase in dietary ractopamine. Carcass weight was increased (P < 0.001) by dietary ractopamine in all sexes, whereas back fat tended (P = 0.076) to be reduced in the immunocastrated boars. Dietary ractopamine increased (P = 0.018) lean tissue mass by 4.0, 4.8, and 6.5 kg in the intact boars, gilts, and immunocastrated boars, respectively. In the entire and immunocastrated boars, the increase in lean tissue was accompanied with a decrease (P = 0.004) in fat mass. There was little effect of dietary ractopamine on fat mass in gilts. However, carcass percent fat was decreased (P = 0.004) and percent lean increased (P= 0.006) in all sexes. Immunocastration caused a decrease in lean tissue mass and an increase in fat mass and an increase in ADFI in the last one-half of the study. Dietary ractopamine may decrease fat mass in intact and immunocastrated boars and offers an excellent
means of maximizing the effects of immunocastration and minimizing the increase in fat mass sometimes observed in immunocastrated boars.
Keyword boar
body composition
growth
immunocastration
ractopamine
finishing pigs
porcine somatotropin
dietary ractopamine
tissue deposition
vaccine improvac
lipid deposition
energy-intake
treated pigs
back fat
protein
Q-Index Code C1
Q-Index Status Confirmed Code

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2010 Higher Education Research Data Collection
School of Agriculture and Food Sciences
 
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Citation counts: TR Web of Science Citation Count  Cited 34 times in Thomson Reuters Web of Science Article | Citations
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Created: Thu, 12 Nov 2009, 21:58:18 EST by Mr Andrew Martlew on behalf of School of Animal Studies