Recent rains caused delays in completing the wheat harvest leading to reports of damaged wheat, particularly in the northern areas of South Dakota. If the damage levels are high enough, the wheat can be unmarketable through regular channels. Feeding damaged wheat to cattle can be a way to salvage the crop.
If cattle producers are thinking about feeding the damaged wheat, Warren Rusche, SDSU Extension Cow/Calf Field Specialist said they need to consider factors such as vomitoxin or ergot which may affect cattle health and performance.
Vomitoxin is a mycotoxin that may be produced in wheat grain infected by Fusarium head blight or scab.
The FDA guidelines on vomitoxin for feedstuffs fed to beef cattle older than four months is 10 parts per million (ppm), as long as the affected feed does not exceed 50 percent of the diet. Rusche said that because wheat is rapidly fermented in the rumen, wheat grain should be limited to 40 percent of the diet to reduce the chances of digestive upset .
"Be extremely cautious feeding wheat screenings. The cleaning process removes a large percentage of the smaller, scab-infested kernels resulting in increased concentration of any mycotoxins present," Rusche said.
Rusche said the safest option is to not feed wheat screenings from scab-infested wheat at any level.
If they are fed, these feedstuffs have to be lab tested prior to feeding. "The risk level of the grain cannot be determined by visual examination, as not all wheat with scab contains vomitoxin and those levels do not necessarily correlate with the physical symptoms in the grain. The only certain measure is a lab analysis," Rusche said.
These mycotoxins can also be found in wheat straw. Rusche said the safest option would be to use straw from fields known to contain vomitoxin as bedding for feedlot or mature cattle. "If the straw is to be fed, it should be tested prior to feeding and diluted accordingly," he said.
Ergot in wheat has also been reported in northern South Dakota in 2015. Wheat containing more than 0.05 percent ergot may be rejected in the commercial grain trade.
Studies show that ergot concentrations greater than 0.1 percent have affected cattle performance.
More information on ergot and potential problems with livestock can be found at iGrow.org.
Delayed harvest can also lead to issues with sprouted wheat. "This grain will be significantly discounted in commercial channels. However, there have been no performance losses observed in cattle feeding trials, indicating that marketing sprouted grain through cattle is a viable option," Rusche said.
He added that these grains should still be tested for vomitoxin and fed at no more than 40 percent of the diet dry matter.
Other tips for feeding wheat (normal or damaged) include:
- Adapt cattle by introducing wheat at low levels (10 to 15 percent of the diet) and increase that amount in steps over a number of days.
- Wheat should be coarsely cracked for improved digestibility, but not finely ground.
- Including an ionophore will help reduce over consumption and acidosis.
- Do not feed wheat in a self-feeder.
Source: SDSU Extension