sealPurdue News

September 1997

With all-in/all-out, hog producers may not need antibiotics

WEST LAFAYETTE, Ind. -- Many hog producers use antibiotics to help keep hogs healthy. In some situations, antibiotics are warranted. However, a Purdue University study suggests that hogs raised in all-in/all-out (AI/AO) management systems live in such a disease-free environment that antibiotics could well be a waste of money for the producer.

In an all-in/all-out system, animals of similar age enter and leave a farrowing or nursery unit at the same time.

Purdue animal scientist Mark Diekman and animal sciences graduate student Amy Ice raised 200 barrows in AI/AO and 200 barrows in continuous management systems. Half of each group received antibiotic treatment, the other half did not.

At the end of six months, hogs in the AI/AO group had fewer lung lesions and produced more lean meat than did the hogs in the continuous management system. However, the AI/AO group that was given antibiotics did no better than did the untreated AI/AO group. The researchers' results suggest that for hogs raised in AI/AO management systems, routine use of antibiotics could be a waste of money.

Diekman reported his work last month at the national meeting of the American Society of Animal Science.

CONTACT: Diekman (765) 494-4829; e-mail,

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