Jim House posed an intriguing question during Hog Days in Brandon last week: do hogs have a greater tolerance to fusarium-infected grain than is generally believed?
House is an associate professor of animal science at the University of Manitoba who has done research that suggests the question warrants a closer look.
Grain infected by fusarium head blight can be tainted by deoxynivalenol, or DON. The presence of that mycotoxin in feed grain can adversely affect the health and performance of pigs.
The Canadian Food Inspection Agency’s guidelines state that DON levels in a pig’s diet should be no more than one part per million.
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But House found in his research that pigs, especially barrows, may have a DON tolerance as high as four parts per million.
While he is not yet recommending producers feed grain with that level of infection, he thinks his findings, backed by further research, could eventually lead to a review of the CFIA guidelines for DON-infected grain, particularly for animals being fed for slaughter.
For hog producers and grain growers on the eastern Prairies, a change to those guidelines would be significant.
The region was once considered an ideal place to raise hogs because of affordable feed and abundant farmland. However, that advantage eroded over the past few years, largely because fusarium has plagued the region’s cereal crops.
An ability to feed more fusarium-infected grain to hogs would mean that more cereals grown on the eastern Prairies could be used in hog rations rather than shipping it elsewhere for cattle feed. At the same time, it would save hog producers the expense of importing feed grain from outside the region.
House conducted three trials using fusarium-infected barley. The first trial was done two years ago with grower-finisher pigs. Feed intake was significantly reduced when DON levels were at two parts per million, but there wasn’t a severe impact on barrows’ daily gains or the time it took them to reach 110 kilograms.
That trial did find a difference in the performance of gilts when fed grain with the higher DON level, suggesting they may be more sensitive to the mycotoxin. The difference was evident in average daily gains and in the time needed to reach market weight.
In the second trial, in 2002, DON levels were raised to as high as four parts per million. The findings were even more remarkable.
House found that barrows and gilts posted the same feed intake and average daily gain as those fed barley with little or no DON infection. The time it took them to reach 110 kg was comparable between the groups.
“It’s an indication that perhaps this is an area we should be focusing more attention on.”
A trial with starter pigs was also done in 2002. In feed barley with DON levels up to two parts per million, there was no difference in feed intake, average daily gains or feed conversion efficiency.
“It shows that even with younger pigs, there may be a higher level of tolerance,” House said.
The findings challenge the notion that hogs should be fed grain with DON levels no higher than one part per million. What has not yet been accounted for is the difference between the CFIA guidelines and what House’s research has shown.
He speculated that today’s pigs may have a greater tolerance than those used when the guidelines were set.
As well, most previous studies focused on wheat and corn rather than barley. House said it’s possible barley has unique characteristics that come into play.
He emphasized that the research was only with barley and was directed at pigs grown for slaughter. The concerns about feeding DON-infected grain to breeding animals should not be dismissed, he said.
