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Hardcopy Reference:	PW 040205-03
Title:	The Way Pigs Eat
Author(s):	Gonyou, H.W.
Publication Year:	1998
Reference:	Centred on Swine Volume 5, Number 2. Prairie Swine Centre. 1998.
Country:	Canada
Summary:	Feeder design improvements in the past 15 years have had a significant impact on pig behaviour, says Dr. Harold Gonyou, research scientist in ethology at the Prairie Swine Centre Inc. Today’s feeder models provide pigs with adequate space to show normal feeding behaviours along with easy access to feed. “With those two changes in design elements, we have more pigs eating out of a feeder hole, eating more quickly and without having to work as hard to get access to feed. As a result, we’ve reduced feed wastage.” A decade ago, feeders with a feed wastage of less than 8% were the industry’s accepted norm. In comparison, all of the 12 feeders tested by PSCI had feed spillage rates of less than 5%, says Gonyou. Eating Behaviour As researchers observed pigs using the different feeder types, Gonyou says they had to determine the reasons for the animals’ eating behaviours. “You have to decide if you’re seeing a facilitation of eating — something about the way you’re presenting food that makes it easier to eat — or if you’re seeing the pigs trying to cope with a limitation of the feeder.” Researchers saw both types of responses associated with the speed at which the pigs ate and the amount of time they spent eating during the day. For example, pigs on wet/dry feeders ate approximately 25% faster than pigs eating on dry feeders. “It’s easier eating slightly wet, mash feed than eating dry feed,” explains Gonyou. But researchers also observed that pigs spent less time eating from single space dry feeders which were in high demand. “That indicates that the pigs are starting to experience some stress related to feeder availability. They would eat faster because there wasn’t much time available to eat from the feeder,” says Gonyou. “The combination of a reduction in total eating time and shorter meals suggests that those pigs were in a crowded situation related to feeder space.” The combined effects of single space and dry feeders resulted in an average feeder occupancy rate of more than 80%, which would be even higher for small pigs. Gonyou says the effects of overcrowding feeders can be seen in the first three weeks after weaning: “This is the period of a pig’s life when the number of pigs per feeder space is most critical.” Feed Wastage Small and large pigs spilled a similar amount of feed, but since large pigs eat more than small pigs, feed spillage as a percentage of total feed disappearance differed significantly (4.4% for small pigs, 2.4% for large pigs). Rooting was the most common behaviour associated with feed wastage for all pig sizes. Smaller pigs spilled feed when they stepped inside feeders to reach their feed, a common occurrence since feeders are built to accommodate market-sized animals. “For our smallest pigs (25 kilograms), the size of some of these feeder spaces was large enough for two pigs to eat from. When you get two pigs doing that, they start fighting and waste feed,” notes Gonyou. More feed was spilled from wet/dry feeders than from dry feeders. But since more feed was consumed from the wet/dry feeders, there wasn’t any significant difference in spillage as a percentage of total feed consumed. Dry feeders had very small spillage areas compared to wet/dry feeders. “Because the feed would stick onto the pigs as they backed out, we would find spilled feed several feet away from the wet/dry feeders,” says Gonyou. Large pigs left four times as much feed in the feed bowl than did small pigs, mainly because they couldn’t clean feed out corners with their larger snouts. Ergonomics If feeder designs don’t fit the animals’ natural behaviour, it can slow down pigs’ eating speeds and cause more feed wastage as pigs adapt their behaviour to the situation, explains Gonyou. Using a specially designed, adjustable feeder, researchers conducted five ergonomic studies on grower-finisher pigs. Research showed that the deeper the feeder, the more often smaller pigs would step in. Another finding was that pigs do not prefer to stand at a 90 degree angle when they’re eating feed. “We’ve built our feeders believing that pigs want to go straight in and eat,” says Gonyou. “That works if the feed is in a pile and on the floor. But if the feed is against a vertical surface, the pigs end up twisting their bodies and rotating their heads. They’re trying to get the best angle so they can eat out of the corner.” The study’s findings suggest that feeders which allow pigs to enter at an angle may speed up pigs’ eating, but more work needs to be done to determine the practicality of such a design.
Abstract:
Database:	Prairie Swine Centre
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