SASKATOON — Fusarium has become the top problem affecting grain crops this year.
“About 60 percent of samples of wheat and barley are being downgraded on account of fusarium damage,” said Daryl Beswitherick of the Canadian Grain Commission.
So far, analysts have not distinguished between fusarium avameceum or the more toxic form, graminearum, which produces mycotoxins harmful to animals.
Levels of contamination vary from slight to 17 to 20 percent damage, Beswitherick said.
Fusarium-contaminated grain is well known for its effects on livestock. It is particularly toxic to swine.
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Ergot in cereal grains may also be a problem this year, said Denise Beaulieu of the University of Saskatchewan.
“I would not take a chance in feeding it to my sows,” she said at the western nutrition conference held in Saskatoon Sept. 20-22.
“Feeding it to your beef or dairy cows is not a solution to dealing with ergot.”
Fusarium graminearum produces vomitoxin also known as deoxynivalenol (DON). While there are feed mixing techniques to reduce the risk of many other mycotoxins, there has been less success with DON.
Testing must to be carried out to determine what form of fusarium is present but it can be expensive, Beaulieu said.
The Canadian Food Inspection Agency provides legal limits on the amount of alflatoxins that may be blended into feed, but there is not similar information about vomitoxin.
Different species experience varying levels of sensitivity to amounts blended into feed. Very small amounts at two parts per million or two kernels per bushel of wheat can be troublesome.
Contamination is found on the outer layer of the kernel.
One project tried pearling the barley to remove DON. The technique worked but a lot of the barley was lost so this abrasive form of removal has not found acceptance within the feed industry.
Kernel sorting technology is available. The Swedish company BoMill has an effective grain quality sorting technology and can handle about 30 tonnes of grain per hour.
Considerable research on swine of all ages has searched for ways to remove the harmful impacts of DON in grain.
Feed additives like charcoal, activated clay or silicates offer an alternative to removing mycotoxins from the grain.
These bind and decrease the absorption of the mycotoxins in the gut. They work well on other toxins but not DON.
“We have had less success removing DON from the diet with the use of these binders,” she said.
Research has also monitored growth rates among different ages of pigs fed corn-based diets contaminated with DON. Additives were used but none of them were able to return to the growth seen when the pigs ate clean grain.
An experiment on the effect of DON on the average daily gain in weaner pigs showed a decrease in growth, yet some of the animals did fine and did not seem to suffer ill effects.
Researchers would like to learn why some of these pigs handled this grain better than others.
Other projects have found combinations of clay and yeast additives reversed some of the negative effects on mycotoxins.
There has also been some success among commercial entities but their techniques to reduce DON are proprietary.
Adding charcoal or enzymes have all had a measure of success but more research is needed.
An Agriculture Canada project is also looking to see if a soil bacteria added to feed could improve intake and growth while mitigating the harmful effect of DON. This is promising work, said Beaulieu.
Another project used spray-dried porcine plasma plus clay to help reduce the negative effects of the DON and encourage growth.
“We know spray-dried plasma helps improve animal performance overall,” she said.
There was some speculation this treatment success could be due to positive effects on intestinal morphology but researchers are not sure if this was the connection. The research ended when a possible connection was made between the spread of porcine epidemic diarrhea and blood plasma in feed.
“We wanted to do further work in this area but unfortunately several years ago PED came along and with the association of porcine plasma and PED, our barn manager did not think this was an important area (of research),” she said.
Some work was done using bovine plasma, but it is not possible to compare the two products at this time.
Beaulieu said the entire question of mycotoxins needs more work and researchers are looking for data from Western Canada. Most of the research has been on corn-soybean based diets rather than wheat-barley based diets.
barbara.duckworth@producer.com
- It affects the gastro-intestinal tract.
- Levels of one to two parts per million cause a reduction in feed intake and affect rate of gain.
- Between 0.5 and three p.p.m., it is wise to dilute with clean grain.
- As levels increase above five ppm, decrease in feed intake may become severe.
- Levels of 10-20 p.p.m. cause vomiting and complete feed refusal, resulting in reduced body weight gain or body weight loss.
- Pigs will initially consume sufficient amounts of the ration to induce vomiting, but will voluntarily reduce intake to stop vomiting.
- Sows are more tolerant than young pigs.
- Low levels can suppress the immune system.
- Source: Ontario Agriculture
