MANAGEMENT
PIH-116
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PURDUE UNIVERSITY COOPERATIVE EXTENSION SERVICE • WEST LAFAYETTE, INDIANA
Handling Hogs
Authors
Temple Grandin, University of Illinois Kenneth and Debra Ernst, Sidney, Ohio John McGlone, Texas Tech University
Reviewers
John Albrecht, Clemson University Bob and Mary Hommez, Osage, Iowa Herman Mayes, University of Missouri S. H. Pohl, South Dakota State University
Introduction
Gentle handling and good husbandry practices will improve swine productivity. A recent study has documented that on farms where sows showed little fear of humans, reproductive performance was high. On other farms, where sows were fearful of humans, reproductive performance was lower [1],
Outside of daily handling, most growing pigs are “worked” at discrete stages of production. These include, but are not limited to, processing at birth (see PIH-I14), castration, weaning and moving to nursery, moving to growing building and finally moving to the finishing building (if a separate growing, finishing building is used) and shipping to market. Sows (and for the most part boars) are handled at breeding, pregnancy checking, vaccination, and weaning (See PIH fact sheets, 1, 74, and 89).
Handling Pigs
Pigs are handled for specific reasons, such as giving medication or redistributing into larger or different pens. Each time pigs are handled, the producer must ask if the benefits of handling exceed the possible performance setback. Animals accustomed to frequent, close, gentle contact with handlers are less likely to experience a production setback by nonpainful procedures such as weighing or being driven down the aisle. Painful procedures or rough handling are more likely to set pigs back. For maximum reproductive performance the person who manages breeding animals should not perform painful procedures on them.
Research has shown that people entering the finishing pens and walking the aisles once a week had no effect on weight gain, if the animals were handled gently [2,3]. 1 he animals became accustomed to people in the pens and did not become excited. However, weight gains were lowered and stress hormone levels increased if a handler occasionally slapped or shocked the pigs with a prod [4]. Even
though the handler was gentle most of the time, the pigs probably became stressed when he entered their pen, because they feared a possible unpleasant experience.
Mixing and Fighting. When pigs first meet, they go through a period in which they establish social relationships. One pig dominates, and the others become subordinate. In a socially-stable pen, which is the desired environment, each pig has a stable social relationship with each other pig.
Establishment of the social order requires that some, but not all, pigs fight. Some pigs submit without a fight. When pigs fight, they do not eat. Even the pigs who submit without fighting do not eat very much while other pigs are fighting. This reduced feed intake reduces weight gain. Newly weaned pigs do not eat much anyway; therefore, fighting does not have measurable negative effects on their performance. Older growing pigs, however, are eating at a productive rate and any disruption in feeding (such as occurs when pigs fight) causes reduced weight gain. The older and heavier the pigs are, the more negative the effects of fighting (see Table 1) [5,6], Larger pigs (especially over 150 lbs.) are very strong and can cause large wounds and extensive injuries. Mixing pigs over 150 lbs. should be avoided as much as possible. If many pigs gang
       Table 1.	Relative pig performance setback because of mixing pigs and fighting.		
Weight at	Weight gain	Added days	Other
mixing	depression	to market	problems a
	None measurable	0	Wounds
40-80	7 days	0	Wounds
80-150	28 days	0	Wounds and injury
over 150	28 days	7 or more	Wounds and injury
   a Other problems associated with social		stress include	
tail-biting, ear-chewing, prolapsed rectum, abscesses, and increased disease.			
Cooperative Extension work in Agriculture and Home Economics, state of Indiana, Purdue University and U.S. Department of Agriculture cooperating. H.A. Wadsworth, Director, West Lafayette, IN. Issued in furtherance of the acts of May 8 and June 30, 1914. The Purdue University Cooperative Extension Service is an affirmative action/equal opportunity institution.