What are the symptoms cattle have if they consume high levels of nitrate in stalks or silage? At extreme high nitrate levels, the first symptom you might see sometimes is a dead cow. That's not common. But there are concerns with moderate issues such as possible problems with reproduction in cows, for example. "If a cattle producer does have concerns about nitrate in cornstalks I'd encourage them to contact their nutritionist or veterinarian and discuss this," says Loy. "I don't think it's something to be alarmed about, yet it is something to watch as we go through this fall."
Aflatoxin levels in corn are also important to livestock feeders
What about aflatoxin issues in corn grain harvested this fall? "There are spotty areas around the state reporting some aflatoxin in corn," says Loy. "The good news regarding aflatoxin is the level that can be fed to beef cattle, especially finishing cattle, is up to 300 parts per billion or pbb. From the levels I've heard about showing up in Iowa so far, there are very few cases, if any, that have reached that level."
Livestock are usually the market for aflatoxin-infected corn. Livestock can tolerate some level of aflatoxin, but levels above legal limits can cause problems in livestock. Reduced performance, immunosuppression, liver damage and in extreme cases even death can be the result of feeding high levels of aflatoxin.
The federal Food and Drug Administration has approved these aflatoxin levels for safe use: Feedlot cattle—less than 300 ppb; finishing cattle—less than 200 ppb; Breeding cattle and breeding swine—less than 100 ppb; dairy cattle, young cattle or young swine—less than 20 ppb; intended use not known—less than 20 ppb; human food—less than 20 ppb. For mature poultry and sheep the safe level for feeding corn containing aflatoxin is less than 100 parts per billion.