|
|
||||||||
ANIMAL PRODUCTS |

* Edgar L. Rhodes Center for Animal and Dairy Science, University of Georgia, Athens 30602-2771; and
and
Elanco Animal Health, a Division of Eli Lilly and Co., Indianapolis, IN 46240
2 Correspondencephone: 706-542-0997; fax: 706-542-0399; e-mail: dpringle{at}uga.edu.
Crossbred barrows (n = 144; 80 kg) from four farrowing groups were phenotypically selected into fat (FAT) and lean (LEAN) pens using ultrasound. The difference in 10th-rib fat depth between the LEAN and FAT groups was
0.5 cm. Within a farrowing group, pigs were assigned to pens (five pigs per pen and eight pens per phenotype) to equalize pen weight and fat depth. Pigs were fed a corn-soybean meal diet containing 19% CP, 1.0% added animal/vegetable fat, and 1.1% lysine (as-fed basis). Half the pens received 10 ppm (as-fed basis) of ractopamine (RAC) during the 28-d finishing phase. At 7-d intervals, live weight and feed disappearance were recorded to calculate ADG, ADFI, and G:F, and 10th-rib fat depth and LM area were ultrasonically measured to calculate fat-free lean and fat and muscle accretion rates. During the first 7 d on feed, LEAN pigs fed RAC gained less (P < 0.05) than FAT pigs fed RAC or LEAN and FAT pigs fed the control diet (RAC x phenotype; P = 0.02); however, RAC did not (P > 0.25) affect ADG after the second, third, and fourth weeks, or over the entire 28-d feeding period. Although wk-2 and -3 ADG were higher (P
0.03) in LEAN than in FAT pigs, phenotype did not (P = 0.08) affect overall ADG. Dietary RAC decreased (P
0.05) ADFI over the 28-d feeding trial, as well as in wk 2, 3, and 4, but intake was not (P > 0.20) affected by phenotype. Neither RAC nor phenotype affected (P > 0.10) G:F after 7 d on trial; however, RAC improved (P
0.04) wk-3, wk-4, and overall G:F. Lean pigs were more efficient (P
0.05) in wk 2 and 3 and over the duration of the trial than FAT pigs. Ultrasound LM accretion (ULA) was not (P
0.10) affected by RAC; however, LEAN pigs had greater (P
0.02) ULA in wk 2 and 4 than FAT pigs. Although fat depth was lower (P < 0.01) in RAC-fed pigs than pigs fed the control diet, ultrasound fat accretion rate indicated that RAC-pigs deposited less (P = 0.04) fat only during wk 4. In addition, calculated fat-free lean (using ultrasound body fat, ULA, and BW) was increased (P < 0.05) in RAC pigs after 3 and 4 wk of supplementation. In conclusion, RAC enhanced the performance of finishing swine through decreased ADFI and increased G:F, whereas carcass lean was enhanced through decreases in carcass fat and increases in carcass muscling.
Key Words: Growth Fat-Free Lean Phenotype Ractopamine Swine
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] |
||||
![]() |
G. J. Hausman, M. V. Dodson, K. Ajuwon, M. Azain, K. M. Barnes, L. L. Guan, Z. Jiang, S. P. Poulos, R. D. Sainz, S. Smith, et al. BOARD-INVITED REVIEW: The biology and regulation of preadipocytes and adipocytes in meat animals J Anim Sci, April 1, 2009; 87(4): 1218 - 1246. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. M. Fernandez-Duenas, A. J. Myers, S. M. Scramlin, C. W. Parks, S. N. Carr, J. Killefer, and F. K. McKeith Carcass, meat quality, and sensory characteristics of heavy body weight pigs fed ractopamine hydrochloride (Paylean) J Anim Sci, December 1, 2008; 86(12): 3544 - 3550. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. K. Apple, C. V. Maxwell, B. R. Kutz, L. K. Rakes, J. T. Sawyer, Z. B. Johnson, T. A. Armstrong, S. N. Carr, and P. D. Matzat Interactive effect of ractopamine and dietary fat source on pork quality characteristics of fresh pork chops during simulated retail display J Anim Sci, October 1, 2008; 86(10): 2711 - 2722. [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] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |