Journal of Animal Science, Vol 69, Issue 7 2685-2693, Copyright © 1991 by American Society of Animal Science

JOURNAL ARTICLE

Effects of ractopamine, genotype, and growth phase on finishing performance and carcass value in swine: I. Growth performance and carcass merit

Y. Gu, A. P. Schinckel, J. C. Forrest, C. H. Kuei and L. E. Watkins
Dept. of Anim. Sci., Purdue University, West Lafayette, IN 47907.

A replicated factorial experiment using 183 individually fed crossbred barrows was conducted. Pigs were fed an 18.5% CP (.95% lysine) diet with 3,594 kcal of ME/kg. The effects of five genotypes (GT): 1) Hampshire (H) x (H x Duroc [D]), 2) synthetic terminal sire line, 3) (H x D) x (Landrace [L] x [Yorkshire (Y) x D]), 4) L x (Y x D), and 5) Y x L; two levels of ractopamine (RAC) treatment: 0 and 20 ppm; and three treatment weight periods (WT): 1) 59 to 100, 2) 73 to 114, and 3) 86 to 127 kg live weight on growth performance and carcass traits were evaluated. Ractopamine increased (P less than .0001) amount (FSL) and percentage (PFSL) of carcass lean standardized to 10% fat content, loin eye area (LEA), and dressing percentage (PDRES) and reduced (P less than .01) amount (DF) and percentage (PDF) of dissected fat. Magnitudes of RAC effects were smaller than those reported by other researchers. Effects of GT and WT on all growth and carcass traits were highly significant (P less than .001) except for those of WT on ADG (P less than .05) and GT on average feed intake (AFI) and backfat thickness at the last rib (BFLR; P less than .05). Genotype 3 performed better for most economically important traits than did GT 1 and 4, suggesting that heterosis existed in GT 3, which essentially was obtained by crossing GT 1 and 4. Among the three treatment periods, WT 2 had the highest ADG. As BW increased from WT 1 to 3, AFI and AFI/ADG ratio (FCR) increased and lean percentage decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

This article has been cited by other articles:

				C. Rikard-Bell, M. A. Curtis, R. J. van Barneveld, B. P. Mullan, A. C. Edwards, N. J. Gannon, D. J. Henman, P. E. Hughes, and F. R. Dunshea Ractopamine hydrochloride improves growth performance and carcass composition in immunocastrated boars, intact boars, and gilts J Anim Sci, November 1, 2009; 87(11): 3536 - 3543. [Abstract] [Full Text] [PDF]

				R. Poletto, M. H. Rostagno, B. T. Richert, and J. N. Marchant-Forde Effects of a "step-up" ractopamine feeding program, sex, and social rank on growth performance, hoof lesions, and Enterobacteriaceae shedding in finishing pigs J Anim Sci, January 1, 2009; 87(1): 304 - 313. [Abstract] [Full Text] [PDF]

				J. N. Marchant-Forde, D. C. Lay Jr., R. M. Marchant-Forde, K. A. McMunn, and B. T. Richert The effects of R-salbutamol on behavior and physiology of finishing pigs J Anim Sci, November 1, 2008; 86(11): 3110 - 3124. [Abstract] [Full Text] [PDF]

				S. L. Gruber, J. D. Tatum, T. E. Engle, M. A. Mitchell, S. B. Laudert, A. L. Schroeder, and W. J. Platter Effects of ractopamine supplementation on growth performance and carcass characteristics of feedlot steers differing in biological type J Anim Sci, July 1, 2007; 85(7): 1809 - 1815. [Abstract] [Full Text] [PDF]

				J. A. Baszczak, T. Grandin, S. L. Gruber, T. E. Engle, W. J. Platter, S. B. Laudert, A. L. Schroeder, and J. D. Tatum Effects of ractopamine supplementation on behavior of British, Continental, and Brahman crossbred steers during routine handling J Anim Sci, December 1, 2006; 84(12): 3410 - 3414. [Abstract] [Full Text] [PDF]

				T. A. Armstrong, D. J. Ivers, J. R. Wagner, D. B. Anderson, W. C. Weldon, and E. P. Berg The effect of dietary ractopamine concentration and duration of feeding on growth performance, carcass characteristics, and meat quality of finishing pigs J Anim Sci, November 1, 2004; 82(11): 3245 - 3253. [Abstract] [Full Text] [PDF]

				J. N. Marchant-Forde, D. C. Lay Jr., E. A. Pajor, B. T. Richert, and A. P. Schinckel The effects of ractopamine on the behavior and physiology of finishing pigs J Anim Sci, February 1, 2003; 81(2): 416 - 422. [Abstract] [Full Text] [PDF]