Newsletter
May, 2001
September, 2001
BioCycle Products

This mycotoxin review covers 50 TMR (total mixed ration) samples collected in California, Oregon, Washington and British Columbia during the last quarter of 2000 and the first quarter of 2001. Participating dairies represent varied facilities, management practices and silage handling skills. They range in size from about 100 milking cows to several thousand. All samples submitted were included in the review. TMR samples were collected from dairies that utilize some silage and/or haylage.

Samples of TMR were sent to the same laboratory. Generally speaking, they were tested for aflatoxin, deoxynivalenol (DON or vomitoxin), T-2 toxin and zearalenone (Z). Some of the early samples were not tested for T-2. It should be considered that while approximately 350 mycotoxins have been identified, we assayed for four as an indication of the presence of these debilitating chemicals. These four were selected because of their importance throughout the United States and Canada. Aflatoxin is known to depress the immune system and cause liver damage. DON can be responsible for feed intake, lower milk production, elevated somatic cell counts and poor reproductive response. Ruminants consuming high levels of T-2 may demonstrate reduced feed intake, intestinal hemorrhaging, a depressed immune system, frequent defecation and high death loss. Zearalenone can be responsible for poor estrogenic response, drops in reproduction and enlarged mammary glands in virgin heifers. When present with other mycotoxins or pathogens, mycotoxins may compound symptoms or demonstrate completely different disease syndromes.

Participants were instructed to follow this protocol when collecting samples:

• Collect a two-pound sample daily for five to seven days

• Keep samples refrigerated during the collection period

• Mix and take a composite two-pound sample from the daily samples

• Freeze the composite and send it to the laboratory via second-day air

Because of interaction of mycotoxins, pathogens and environmental conditions (ie synergisms and antagonisms) and because of the probable presence of toxins not assayed, we tend to judge debilitation by the presence of multiple toxins rather than the quantity of individual toxins (see “How much is safe?” Lamb, 2001).

Samples were sorted by geographic region (Southern California, Northern California and the Northwest). California was divided north and south at Bakersfield. At least two mycotoxins were found in 98% of the samples tested. Forty-two percent of the samples were positive for all mycotoxins assayed (see table #1).

Aflatoxin
Aflatoxin was found to be present in 94% of the rations. With the exception of a few samples, levels found would not be considered problematic if it weren’t for the certainty of interactions. Interestingly, 59% of the samples containing aflatoxin (a mycotoxin produced by Aspergillus molds) also tested positive for at least two other mycotoxins produced by Fusaria molds.

Deoxynivalenol
In a North Carolina State University study (Whitlow et al., 1991), a level of 0.5ppm of deoxynivalenol (DON) was found to cause a three-pound decrease in the milk production of lactating dairy cattle. Ninety percent of the samples tested at or above 0.5ppm (see table #2). It is safe to say that DON reduces productivity on most dairies regardless of other mycotoxins present.

T-2 Toxin
T-2 toxin is a particularly debilitating mycotoxin. It attacks the organs and produces symptoms that are similar internal diseases. Due to local silage handling practices, T-2 was highest in Southern California, however, frequency of positive assays and quantities of T-2 found are problematic throughout the west.

Zearalenone
Zearalenone is frequently responsible for breeding difficulty and production problems. It proves to be illusive to laboratory assays. While the percentage of positive assays was similar in all areas, quantities found were highest in the northwest where climatic conditions are optimum for Fusaria production.

Summary:
Mycotoxins were affecting production and/or health to some extent in most, if not all, of the participating dairies. Participating dairies were typical in size, production and management practices.

While toxins tend to run higher in rations containing more haylage than silage, quantities found tend to fluctuate more with management skill than with type of storage. Quantities of mycotoxins found were greater in high-moisture, wrapped bales (popular in the northwest).

Select DTX or Bio Cycle Plus should be incorporated into total mixed rations routinely, particularly when silage and haylage are used.

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