Newsletter
June, 2001
September, 2001
BioCycle Products

How much is safe?
As we discuss molds and the effect of their secondary metabolites, mycotoxins, on dairy cattle with veterinarians, nutritionists and dairymen a question frequently asked is: "What level of mycotoxins is safe in a dairy ration?" or conversely, "what level of mycotoxins will cause problems?" In recent continuing education programs throughout the west we recommended that you discount the advice of any technician who is willing to give you a definitive answer to this question for the following reasons:

• No one really knows. Current industry standards estimate the affect of single toxins in a controlled, stress free, sterile ‘lab’ environment. Lab dosing has little to do with field dosing. It can be said that debilitating lab dosing is 10 to 100 times greater than field dosing.

• One strain of mold may produce more than one toxin and the toxins produced from one strain of mold may be different depending on conditions when the spore is releasing its secondary metabolites.

• Chronic dosing may cause a completely different disease syndrome than acute dosing.

• Interactions (i.e. synergism, antagonism, etc.) occur. There are over 350 identified mycotoxins; a feed ingredient or total mixed ration rarely, if ever, has just one. Animal science is beginning to understand that these complexities exist. If science could predict the symptomatic affect of a single mycotoxin in a sterile, stress free environment, it could not predict the debilitation caused by the same toxin in company with others or when it is present at the same time as environmental or pathogenic stress.

The following study (Jones et al.) demonstrated the affect on aflatoxin and Treponema hyodysenteriae, a known diarrhea causing pathogen, on the onset of diarrhea and death in swine when they are introduced individually and together. Aflatoxin caused no scours when introduced alone (aflatoxin is not recognized as a diarrhea causing agent). The introduction of treponema caused diarrhea on the 17th day, duration was 8 days and there was 12% mortality. When the two were introduced at the same time the days to onset was cut in half, duration doubled, and death loss increase over 4 fold. In this typical interaction, aflatoxin caused, or at least increased the effect of, a disease syndrome that it is not known to produce.

Conclusions:
In late 2000 and early 2001 All West/Select Sires and Agrarian Marketing sponsored the testing of TMR samples from dairies in California, Oregon, Washington and the province of British Columbia. They were tested for aflatoxin, deoxynovalenol (DON), T-2 and zearalenone (Z). 97.8% of these samples tested positive for two or more of the toxins. Researchers at North Carolina State demonstrated that a contamination of 0.5ppm of deoxynovalenol reduced milk production by 3 pounds per head per day. 91.3% of the samples tested had more than 0.5ppm. It seems prudent to accept the following:

• Almost every TMR carries a sufficient load of mycotoxin to debilitate production in livestock to some degree.

• The routine inclusion of DTX or Bio Cycle Plus in most TMR would be economically sound.

• Manage all forages to reduce the rate of mold growth. Clean mixers, augers and other equipment regularly and manage feed bunks well.

• Regular testing for a few mycotoxins makes sense, but don’t pass up the information offered by the best laboratory, dairymen’s own cattle. When milk production or butterfat is lower than expected, when diarrhea strikes, when conception rates dip, or when abortions or mortality increase, take immediate steps to adjust feeding rates of offending ingredients (if possible) and add DTX or Bio Cycle Plus to the feeding program.

For additional information contact:
Don Lamb
Director/Sales - Feed Supplement Division
Cellular: (360) 941-0009
FAX: (360) 835-1607
E-Mail: lambdk@juno.com