Watch your feed corn for mycotoxins

Last fall’s harvest conditions in many key corn-growing areas were conducive to mold growth and mycotoxin contamination. Even if those conditions didn’t exist in your area, purchased corn may come from miles away and could be a problem.

Also be cautious regarding the ever-increasing availability of distillers grains. Corn is often shipped long distances to ethanol plants. The fermentation process concentrates non-starch components — including mycotoxins — in the distillers grains.

Specialists from five land-grant universities — Penn State, Purdue, Ohio State, Iowa State and Kentucky — are cooperating to keep an up-to-date report on this problem. While visual appearance of molds is a warning sign, mycotoxin-infected grain can look normal.

If your livestock feed intake or production seems off, consider having the feed analyzed, and be certain of the type and level of any mycotoxins. At the farm level, it’s often possible to formulate a safe ration by blending the infected feed with safe feedstuffs.

Key Points

• Feed corn and distillers grains may harbor mycotoxins.

• Watch for changes in appetite, feed refusal and poor weight gain.

• Sample and test suspect feeds to develop an alternative feeding plan.

Signs of feed toxins

General symptoms of mycotoxicosis are: loss of appetite, poor weight gain, feed refusal, diarrhea, bleeding and unthriftiness. Grain quality problems are often aggravated by poor storage conditions. The most likely culprits are:

Fumonisins: These toxins are produced by Fusarium species that grow on corn in the field or in storage. High levels of fumonisins are associated with hot and dry weather followed by periods of high humidity.

Trichothecenes: More commonly referred to as vomitoxin or deoxynivalenol (DON), these are important to livestock and poultry producers. Most animals refuse to eat feeds with high concentrations of them.

Ochratoxin: This toxin is produced by some species of Penicillium and Aspergillus fungi in cereal grains. It affects kidney function in animals. Optimal conditions for ochratoxin production are at a temperature range between 68 to 77 degrees F and a crop moisture content of 16% or above.

Sample and test

If you have suspect feeds, there’s no substitute for a mycotoxin analysis at a reputable lab. For a thorough discussion of how to sample and send feedstuffs, as well as a listing of 13 laboratories in several different states, see www.oardc.ohio-state.edu/ohiofieldcropdisease/wheat/mycotoxin%20text2.htm.

Harpster is a Penn State animal scientist and a beef cow-calf producer.

This article published in the March, 2010 edition of AMERICAN AGRICULTURIST.

All rights reserved. Copyright Farm Progress Cos. 2010.