| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
ANIMAL PRODUCTION |
* Department of Animal Sciences, Colorado State University, Fort Collins 80523-1171; and
Elanco Animal Health, Greenfield, IN 46140
1 Corresponding author: J.Daryl.Tatum{at}Colostate.edu
Effects of ractopamine hydrochloride (RAC) supplementation on growth performance and carcass characteristics of feedlot steers differing in biological type were investigated using British, Continental crossbred, and Brahman crossbred calf-fed steers (n = 420). Steers of each type were weighed at reimplantation [British, mean BW = 375 kg (SD = 38 kg); Continental crossbred, mean BW = 379 kg (SD = 42 kg); Brahman crossbred, mean BW = 340 (SD = 32 kg)] and sorted into 7 BW blocks, each block consisting of 2 pens (10 steers per pen) per type. Pens within a block x type subclass were randomly assigned to RAC treatments (0 or 200 mg · steer–1 · d–1 fed during the final 28 d of the finishing period). The type x RAC interaction did not affect (P > 0.05) any of the traits evaluated in this study. Feeding RAC improved (P = 0.001) ADG (1.50 vs. 1.73 ± 0.09 kg) and G:F (0.145 vs. 0.170 ± 0.005), but did not affect (P = 0.48) DMI of steers. Dressing percentage, adjusted fat thickness, KPH percentage, and yield grade were not affected by RAC supplementation. Carcasses of steers fed RAC had heavier (P = 0.01) HCW (359 vs. 365 ± 4.9 kg), larger (P = 0.046) LM areas (81.7 vs. 84.0 ± 1.1 cm2), and tended (P = 0.07) to have lower mean marbling scores (487 vs. 477 ± 5.2; Slight = 400, Small = 500) than did carcasses of control steers. Among the 3 biological types, Brahman crossbred steers had the lowest DMI and produced the lightest-weight carcasses that had the lowest mean marbling score (P < 0.05). Compared with Continental crossbred and Brahman crossbred steers, British steers produced carcasses with the greatest (P = 0.001) mean marbling scores. Continental crossbred steers had the heaviest BW and greatest dressing percentages and produced the heaviest carcasses with the largest LM areas (P < 0.05) compared with British and Brahman crossbred steers. In the present study, 28 d of supplementation with RAC at a dosage rate of 200 mg · steer–1 · d–1 elicited consistent responses in growth performance and carcass traits among 3 diverse biological cattle types.
Key Words: beef • biological type • breed • carcass • growth • ractopamine
This article has been cited by other articles:
|
|
 |
|
  S. J. Winterholler, G. L. Parsons, D. K. Walker, M. J. Quinn, J. S. Drouillard, and B. J. Johnson Effect of feedlot management system on response to ractopamine-HCl in yearling steers J Anim Sci, September 1, 2008; 86(9): 2401 - 2414. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. J. Quinn, C. D. Reinhardt, E. R. Loe, B. E. Depenbusch, M. E. Corrigan, M. L. May, and J. S. Drouillard The effects of ractopamine-hydrogen chloride (Optaflexx) on performance, carcass characteristics, and meat quality of finishing feedlot heifers J Anim Sci, April 1, 2008; 86(4): 902 - 908. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. L. Gruber, J. D. Tatum, T. E. Engle, K. J. Prusa, S. B. Laudert, A. L. Schroeder, and W. J. Platter Effects of ractopamine supplementation and postmortem aging on longissimus muscle palatability of beef steers differing in biological type J Anim Sci, January 1, 2008; 86(1): 205 - 210. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
