Research at Canada's Prairie Swine Centre (PSC) confirms that use of an electric prod to move market hogs elevates stress levels in the animals vs. other means of handling.

A total of 192 hogs near market weight were walked from their finishing pens in groups of six, through a 984-ft.-long handling course that included numerous turns, curves, reversals and partially obstructed alleys.

The course took an average of 10 minutes to complete. Three handling regimens were imposed on the animals.

Hogs in the gentle treatment group were moved with a herding board, quiet voice and gentle slaps at a comfortable walking pace. These hogs were essentially unstressed by the procedure (Table 1).

Hogs in the second group were handled aggressively, at a fast pace, with shouting and slapping, but without use of an electric prod. These animals showed a higher incidence of stress, but none showed extremes that might lead to animal losses.

For the third group, pigs were moved at a fast pace, a louder voice and use of slapping or an electric prod. The use of the electric prod resulted in more than 40% of the pigs showing behavioral and physiological signs of stress, with 4% to the extreme point of stumbling and falling.

“Losses resulting from aggressively handled pigs can approach 4% in a commercial swine operation,” says PSC researcher Harold Gonyou. “For a 600-sow, farrow-to-finish operation marketing 14,000 hogs/year, assuming a 2% loss due to aggressive handling, this would represent lost revenue on 280 market hogs, or approximately $37,000 for that operation.”

In the trials, pigs that were highly stressed had higher temperatures, lower blood pH and higher blood ammonia levels than did pigs with no outward signs of stress.

“Clearly, we should be minimizing the use of the electric prod when handling animals,” points out Gonyou. “Before prodding a pig while it is being loaded, the handler should consider if another means of encouraging movement could be effective, even if it took slightly longer. If one pig is repeatedly being difficult to move, it should be left behind and perhaps herded separately rather than prodding it again.

“If producers find that they must use the electric prod frequently during the load out process, they should consider changes to their load out design and/or handling techniques.”

Researcher: Harold Gonyou, Prairie Swine Centre, Saskatoon, Saskatchewan. Contact Gonyou by phone (306) 373-9922, fax (306) 955-2510 or e-mail Kenneth Engele, assistant manager, Information Services, PSC, at Ken.Engele@usask.ca.

Table 1. The Incidence of Highly Stressed Pigs
in Three Different Handling Treatments
Aggressive
Gentle No-Prod Prodded
No signs of stress 47 41 54
Highly stressed but not falling 1 7 23
Highly stressed and falling 0 0 9
Total number of pigs 48 48 96
Handling time in course (sec.) 701 467 467

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