The Milk Producer - January 2012 - (Page 36)

RUMINATIONS By Mario S. Mongeon and Tom Wright Contamination to blame? Mycotoxins produced by mold in your grains or feed can seriously impair your herd’s milk production performance I f your cows have gone off feed and milk production has dropped off, mycotoxins in their ration could be the culprit. An ear corn mold survey last fall has shown elevated levels of mycotoxins in some parts of Ontario. Mycotoxin is a generic term for toxic chemicals produced by mold that colonize crops and stored feed. One mold species may produce more than one type of mycotoxin, and various mold species may produce the same mycotoxin. Examples of these toxic chemicals are Aflatoxin, Zeralenone and Vomitoxin (DON). Molds can develop on various feed types at various growth stages—before harvest or during storage. When weather conditions are right for their growth, molds can grow on grain kernels still attached to plants in the field and produce mycotoxins. Corn and wheat, for example, can show significant mycotoxin levels at harvest. Molds can also proliferate on stored feed such as corn silage if oxygen leaks into the silage mass. Moldy feeds can typically cause performance losses of five to 10 per cent, even if they don’t produce mycotoxin. Cattle find moldy feeds less palatable and may reduce their dry matter intake. This lowered nutrient intake reduces weight gains or milk production. When mycotoxins do contaminate your feed, they can cause problems when cattle consume them even at extremely low levels. The toxins can impair performance and change normal metabolism, mainly targeting an animal’s immune function. Young, pre-ruminant calves and high-producing cows are most susceptible to mycotoxins, and cows already stressed by lameness, high temperatures or improper rations are also more at risk. The transition period and at calving time are critical, too. Last fall’s ear corn mold survey, conducted by the Ontario Ministry of Agriculture, Food and Rural Affairs, revealed some fields had elevated levels of DON. Severity varied across the province, but about 12 per cent of fields sampled showed levels between two and four parts per million (ppm). A few fields even had levels in excess of four ppm. Other sources have reported even greater concentrations in feed samples. In one case, a silo of high moisture corn has been analysed at 12 ppm of DON. Other data suggest Zearalenone could be trending higher, more so than DON. Mycotoxin contamination can come from purchased feed sources as well as your fields or silos. Before buying a load of corn distillers grains or similar material, ask for a laboratory report for mycotoxins. The fermentation process does Total Ration (on a dry matter basis) Mycotoxin DON/Vomitoxin Zearalenone T-2 HT-2 Various molds produce mycotoxins in feed. 36 | January 2012 | MilkPRODUCER Concern level (ppm) 0.56 0.56 0.25 0.25 Potentially harmful to cattle (ppm) 2.5 to 6.0 3.9 to 7.0 0.7 to 1.5 1.5 to 3.0 Adapted from Penn State

Table of Contents for the Digital Edition of The Milk Producer - January 2012

The Milk Producer - January 2012
Contents
Editor’s Notes
DFO Chair’s Message
Dairy Update
DFC Promotion
Farm Finance
Research
Applied Science
Ruminations
Rearing Replacements
Markets
New’N’Noted
Back Forty

The Milk Producer - January 2012

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