Gibberella zea, the asexual stage of Fusarium gramineaum, is the cause of head scab in wheat.This is related to the time the wheat head at antithesis is wet with water. Two mycotoxins may be produced by head scab.

• Deoxynivalenol, commonly DON or Vomitoxin,1986 survey .6 to 4 ppm.
• Zearalenone, can be produced in the field or in storage.1986 survey .31 to 3.1 ppm.

Feeding Scabby Wheat to Dairy CattleFeeding wheat to dairy cattle may be an economical alternative to shelled corn this year. The feeding of wheat should be limited to less than one half of the concentrate mix (1). Cattle should be adapted to wheat feeding slowly. Start with feeding 1/4 of the target amount you want to feed and work up from there over a two to three week period.

During this adaption period, record daily dry matter intake and back off, or discontinue, amounts of wheat being fed if dry matter intake decreases by more than 10%. Protein in wheat averages about 12% CP and that of shelled corn about 10% CP. The level of protein supplement feed may be reduced to compensate for wheat higher protein content.

Scabby wheat in 1986 contained between .6 ppm and 4 ppm deoxynivalenol (DON). DON, commonly referred to as vomitoxin. Levels of 10 ppm are generally tolerated by ruminant animals. Lower levels may cause a drop in feed intake and milk production. Monitoring of dry matter intake isgenerally recommended when wheat is used to replace shelled corn in dairy rations and can aid producers in determining the acceptable level to include. Generally, feeding cracked wheat in a total mixed ration (TMR) is the best way to feed wheat and test the cow response. Start with feeding heifers and late lactation groups before feeding wheat to the early lactation cows.