Effect of Space Allowance and Antibiotic Feeding on Performance of Nursery Pigs

The relationship between space allowance and feeding antibiotics to pigs weaned at 3 to 6 wk of age was investigated in a cooperative study that involved nine experiment stations in the North Central Region of the United States. Treatments, arranged factorially, were control vs antibiotics (110 mg chlortetracycline, 110 mg sulfamethazine and 55 mg penicillin/kg of diet) and .14 vs .23 m2 of floor space/pig. Treatments were replicated 45 times, utilizing 1,724 pigs. Pigs allowed .23 m2, compared with .14 m2, had 10.6% greater (P less than .01) rate of gain and 3.6% improved (P less than .05) feed/gain. Pigs fed antibiotics had 13.2% faster (P less than .01) rate of gain and 4.7% improved (P less than .01) feed/gain in the 4-wk experimental period. There were no interactions between antibiotic and space allowance for performance measurements, except for average daily gain (P less than .05) in the 0 to 3 wk period. In this period the antibiotic response was greater among pigs allowed .23 m2, as compared with those allowed .14 m2.