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Carcass and Meat Quality Characteristics of Pigs Receiving Generic Ractopamine (Engain 9® – Zoetis)
The objective of this study was to evaluate carcass and meat quality characteristics of market pigs receiving a generic ractopamine HCl product (Engain 9® - Zoetis; RAC) for 28 days before slaughter. Animals (n=220 pigs; 44 pens) were assigned to the study using a split plot design, with barrows and gilts fed separately and divided equally between control group (CON; no ractopamine) and treated group (RAC) fed at 10 ppm for 28 d. All animals (n=219) were harvested after approximately 16 h feed removal. Eighty eight (88) carcasses (2 per pen) were selected closest to the pen mean to evaluate pork meat quality and carcass cutting yields. Data were analyzed using a general linear mixed model with appropriate fixed and random terms. Pen was the experimental unit. Results for dressing percent are presented by sex as the treatment by sex interaction was significant (p<0.05); all other results are presented by treatment.
Results are presented as least squares mean (LSMean) ± standard error and p-value.
Variable |
CON |
RAC |
P-Value |
HCW, kg |
93.1±0.69 |
98.2±0.69 |
<0.0001 |
Dressing Percent, Barrows, % |
77.8±0.33 |
78.9±0.33 |
<0.0001 |
Dressing Percent, Gilts, % |
78.2±0.3 |
78.7±0.3 |
0.0586 |
Carcass Lean, % |
54.2±0.35 |
55.5±0.35 |
0.0002 |
Loin Depth, mm |
64.3±0.47 |
69.1±0.47 |
<0.0001 |
Loin Eye Area, cm2 |
51.1±0.98 |
56.1±0.98 |
<0.0001 |
Backfat Thickness 10th rib, mm |
19.3±0.55 |
17.7±0.55 |
0.0070 |
Minolta L* |
48.8±0.4 |
48.7±0.4 |
0.7932 |
Minolta a* |
8.9±0.15 |
7.8±0.15 |
<0.0001 |
Minolta b* |
4.0±0.30 |
3.2±0.30 |
<0.0001 |
Warner-Bratzler Shear Force, kg |
3.26±0.16 |
3.62±0.17 |
0.0238 |
Carcass Cutting Yield, % |
77.2±0.29 |
78.3±0.29 |
0.0001 |
Lean Cutting Yield, % |
62.5±0.37 |
63.9±0.37 |
0.0010 |
Boneless Lean Cutting Yield, % |
40.5±0.30 |
42.4±0.30 |
<0.0001 |
No differences were observed in (p>0.05; CON vs RAC) last rib fat thickness (22.4 vs. 22.3 mm), pH (5.52 vs. 5.53), drip loss % (4.79 vs. 4.62), belly flop (21.2 vs 21.1 cm) and belly thickness (3.62 vs 3.73 cm). The 14 day post mortem loin chop Warner-Bratzler Shear Force was increased, similar to values reported in previous RAC studies.
Treatment of pigs with 10 ppm generic RAC showed minimal changes in meat quality but showed improvements in carcass cutting, lean cutting and boneless lean cutting yields. Results were consistent with expectations for pigs treated with RAC.
Keywords: swine, ractopamine, carcass