7/29/97

Contacts:
Liesl Hohenshell, Animal Science, (515) 294-2088
Don Lay, Animal Science, (515) 294-2088
Ed Adcock, Agriculture Information, (515) 294-2314

EARLY-WEANED PIGS STUDIED FOR ABERRANT BEHAVIORS

Nashville, Tenn. -- An Iowa State University research project that weaned pigs earlier than usual failed to find a high rate of abnormal behaviors that have been noted in other studies. The findings were presented at the annual meeting of the American Society of Animal Science July 29-Aug. 1

Producers are weaning earlier and earlier because early-weaning appears to increase growth, decrease disease and frees up space in the farrowing room sooner. But weaning pigs early for segregated- and medicated-early-weaning programs can produce aberrant behaviors that may jeopardize the pigs' welfare. For example, pigs may engage in a variety of sucking, biting and rooting behaviors. It is believed early-weaned pigs engage in these behaviors to satisfy their need to suckle.

"We wanted to see if these behaviors, or excessive energies, followed them through life and keep them from gaining weight properly," said graduate student Liesl Hohenshell, who was supervised in her master's thesis research by ISU animal science professor Don Lay. Sixteen litters of pigs were followed to slaughter and their carcasses analyzed.

Hohenshell weaned eight litters of pigs at 8 to 13 days after birth and weaned the other eight litters at 27 to 34 days (21 days is a typical weaning date for producers). The pigs were weaned without being segregated into a pathogen-free environment. She recorded weight gains of both groups. Time-lapse photography recorded behaviors at 2, 3 and 4 days after weaning. Researchers collected data on the frequency of feeding and drinking and the time spent "play-fighting."

Over the three-day sampling period, there was no difference in the number of pigs eating or drinking, but the early-weaned group spent more time play-fighting. In direct observations there were no differences in time spent lying, standing, sitting or play-fighting, or the frequency of belly-nosing or metal biting. But the early-weaned group manipulated pen mates more than the late-weaned group.

The early-weaned group gained more weight from birth to 42 days of age. Hohenshell attributed the greater weight gain, increased play-fighting and manipulations of pen mates to the early-weaned pigs being more active. The weight advantage of the early-weaned group disappeared as the pigs developed and both groups averaged .7 kilograms a day from birth to slaughter.

Lay said the study's results are encouraging for small pork producers because there does not seem to be a penalty for weaning to an environment that is not pathogen free.

Producers need to follow the basics of providing weaned pigs enough heat in a draft-free room and keeping feed dry to make sure they eat, he added.

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