1952
Effects of added zinc during the grower and/or finisher phase on growth performance and carcass characteristics of finishing pigs fed diets with or without ractopamine HCl
A total of 1,197 pigs (PIC 337 × 1050) were used in a 72-d study to determine the effects of added Zn from ZnO fed during the grower (d 0-45; initially 58.8 kg) and finisher (d 45-72; initially 99.0 kg) in diets with or without ractopamine HCl (RAC; Elanco Animal Health, Greenfield, IN) on growth performance and carcass characteristics. There were 25 pigs per pen and 6 pens per treatment. Pens were randomly assigned to a 2×2×2 factorial arrangement in a split-plot design. The whole plot consisted of diets with or without 75 ppm added Zn from d 0 to 45 and the subplots were diets with or without 75 ppm added Zn and with or without 10 ppm RAC from d 45 to72. All diets contained 50 ppm Zn supplied from the premix. No interactions were observed. Addition of 75 ppm Zn during either period or both did not influence pig growth performance or carcass characteristics. Pigs fed RAC had improved (P<0.03) ADG, G:F, final BW, HCW, loin depth, and fat-free lean index compared with pigs fed the control diet. In conclusion, feeding RAC improved the performance of grow-finish pigs; however, additional Zn did not.
Keywords: growing-finishing pigs, ractopamine HCl, zinc
Table 1. Effects of added zinc during the grower and/or finisher phase on growth performance and carcass characteristics of finishing pigs fed diets with or without ractopamine HCl
Added Zn d 0-45: |
- |
- |
- |
- |
+ |
+ |
+ |
+ |
|
Added Zn d 45-72: |
- |
+ |
- |
+ |
- |
+ |
- |
+ |
|
Added RAC d 45-72: |
- |
- |
+ |
+ |
- |
- |
+ |
+ |
SEM |
d 0 to 72 |
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ADG, kg |
0.89 |
0.88 |
0.95 |
0.95 |
0.89 |
0.88 |
0.97 |
0.96 |
0.01 |
ADFI, kg |
2.65 |
2.60 |
2.60 |
2.63 |
2.69 |
2.68 |
2.71 |
2.72 |
0.05 |
G:F |
0.34 |
0.34 |
0.37 |
0.36 |
0.33 |
0.33 |
0.36 |
0.35 |
0.00 |
Final BW, kg |
118.7 |
118.0 |
122.9 |
123.6 |
119.4 |
118.0 |
124.0 |
124.2 |
2.7 |
Carcass Characteristics |
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HCW, kg |
86.0 |
86.0 |
88.2 |
90.0 |
85.4 |
87.1 |
88.7 |
89.5 |
2.2 |
Yield,1 % |
74.09 |
74.12 |
74.64 |
75.35 |
73.09 |
75.52 |
73.98 |
74.08 |
1.35 |
Backfat thickness,2 mm |
16.75 |
15.69 |
13.81 |
14.86 |
16.29 |
16.28 |
14.13 |
13.67 |
0.63 |
Loin depth,2 mm |
62.64 |
61.71 |
64.59 |
63.12 |
61.99 |
61.58 |
65.52 |
66.06 |
1.13 |
FFLI,2 % |
53.13 |
53.70 |
55.13 |
55.13 |
53.52 |
53.33 |
55.01 |
55.94 |
0.57 |
1Calculated by dividing HCW by live weight obtained at the packing plant. 2Adjusted using HCW as a covariate. |
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