102
Comparison of the effects of antibiotic-free and conventional management on growth performance in swine
Seven hundred and twenty-four, mixed sex pigs were placed in 11 rooms at the Purdue Swine Environmental Research Building to determine the effects of rearing pigs without antibiotics on growth performance. Pigs were blocked by BW and gender and allotted to room and pen with 10 or 11 mixed-sex pigs/pen. Control pigs consumed diets (Table 1) containing antibiotics and were treated with injectable antibiotics when deemed necessary. Antibiotic-free animals consumed diets with alternatives to antibiotics and received no injectable antibiotics. If sick animals did not respond to antibiotic alternatives, they were removed from the experiment. Pigs were weighed at the start and end of each dietary phase, and mortality and morbidity were recorded daily. Data were analyzed using the GLM procedure in SAS. During the nursery phase, control pigs grew faster (P<0.02; 0.449 vs 0.426 kg/d), and consumed more feed (P<0.05; 0.694 vs. 0.660 kg/d) than antibiotic-free animals, resulting in similar G:F. Similar ADG, ADFI and G:F were observed throughout the grower phases, and therefore the increased BW of control-fed pigs was maintained, and tended to be heavier (P=0.06) at the start of the finisher phases (86.0 vs. 84.5 kg). However, antibiotic-free animals grew 3% faster (P<0.01) and had 6% better G:F (P<0.001) in the finisher phases. As a result, there was no overall effect (P>0.10) of treatment on ADG, but there was a trend (P = 0.08) for increased ADFI (2.11 vs. 2.07 kg) and reduced (P<0.05) G:F (0.518 vs. 0.527) in control pigs compared to antibiotic-free. Thirty antibiotic-free animals (8.3%) were removed from the study compared to 11 control (3.0%). In conclusion, antibiotic-free management can yield a similar growth performance to conventional systems, but the limited disease treatment options may limit the number of pigs marketed under this management system.
Table 1. Antibiotic and antibiotic alternative rotations. |
|||
Phase |
Duration |
Antibiotic program |
Antibiotic free program |
Nursery 1 |
1.36 kg/hd |
Carbadox+3,000 mg/kg Zn |
Water Acidification+3,000 mg/kg Zn |
Nursery 2 |
2.5 kg/hd |
Carbadox+2,500 mg/kg Zn |
Water Acidification (13 days total)+2,500mg/kg Zn |
Nursery 3 |
8.18 kg/hd |
Carbadox+2,000 mg/kg Zn |
Direct-fed microbial (DFM)+2,000 mg/kg Zn |
Nursery 4 |
Ad lib to day 42 |
Carbadox+189 mg/kg Cu |
DFM+250 mg/kg Cu |
Grower 1 |
21 days |
Chlortetracycline–50 g/ton |
DFM+126 mg/kg Cu |
Grower 2 |
21 days |
Lincomix–100 g/ton |
DFM+Water Acidification |
Grower 3 |
21 days |
Lincomix–40 g/ton |
DFM |
Finisher 1 |
21 days |
Tylan–20 g/ton |
Oregano |
Finisher 2 |
21 days |
Tylan–10 g/ton |
Oregano |
Keywords: swine, antibiotic, performance