Understanding the mycotoxin challenges in feed ingredient sources
Mycotoxins have a 5 billion USD estimated impact on the US and Canadian animal industries annually. While mycotoxin contamination can be difficult to completely assess due to sampling and testing complexity, it is critical to understand the extent of mycotoxin challenges in feed ingredient sources.
The most common mycotoxins are aflatoxin, deoxynivalenol (also known as DON or vomitoxin), zearalenone, and fumonisin. When determining mycotoxin testing and mitigation plans, watch for key symptoms associated with each of these mycotoxins.
Aflatoxin is a highly toxic and carcinogenic mycotoxin that decreases performance and overall animal well-being. Aflatoxin occurs in corn, wheat, barley, oats, rice, cottonseed, sunflower, nuts, and spices. Aflatoxin is absorbed readily from the gut and is converted to even more toxic compounds in the liver. Like many other mycotoxins, aflatoxins suppress the immune function of animals. In cattle, calves are most susceptible to aflatoxin. In young animals, feed intake is commonly reduced, resulting in depressed growth rate. In lactating cows, if aflatoxin is managed effectively (below 20 ppb in total diet) to avoid risk of aflatoxin M-1 appearing in milk at more than the permitted 0.5 ppb, physiological impacts on the animal are limited.
Symptoms of aflatoxin consumption include:
- Reduced milk production
- Dry, peeling skin on the muzzle
- Liver damage
- Slow growth in growing animals
- Hair loss
- Decreased appetite
- Overall appearance of ill-health
Deoxynivalenol (DON) is a relatively common mycotoxin, especially in the northern half of the US and in Canada. Corn, wheat, barley, oats, sorghum, rye, and all grain silage types are at risk for DON. Feeding DON-contaminated diets has been associated with reproductive problems, although the effect may be partly related to undetected presence of other toxins. DON is one of the most immunosuppressive mycotoxins, causing increased risk from other stressors. Thus, effects are more pronounced in stressed cattle or if DON is combined with other toxins.
Symptoms of DON consumption include:
- Reduced feed intake
- Lowered milk production
- Lower milk fat production
- Higher somatic cell counts
- Decreased rumen function
- Damaged mucous membranes that may lead to diarrhea
Also known as the reproductive mycotoxin, zearalenone and related compounds are most harmful for the breeding herd. Their estrogenic effects produce a range of changes to the reproductive tract that can disrupt reproductive performance. When zearalenone risk is known, it is advisable to monitor grain, grain by-products, and grain forages being used in heifer or cow diets, and to eliminate any known contaminated ingredients from the diets of reproducing animals. Zearalenone is commonly found in corn silage, high-moisture corn, barley, and sorghum. It is often found in conjunction with DON and/or Gibberella ear rot in corn.
Symptoms of Zearalenone consumption include:
- Vaginal or rectal prolapses
- Irregular or missed estrous cycles
- Increased embryonic losses
- Early maturity of mammary glands & reproductive organs
- Reduced conception rates
- Reduced fetal development
- Lower viability of newborns
Fumonisins are fairly common contaminants of grains, grain by-products, and some grain silages, especially in the southern half of the United States. Ruminants tend to be much less susceptible to fumonisin than monogastric species. While limited data is available, it appears much of the fumonisin ingested by cattle ends up in the feces, as it is not readily absorbed or extensively metabolized in the rumen or lower gastrointestinal tract.
Symptoms of fumonisin consumption include:
- Increased mortality
- Decreased feed intake
- Reduced immune response
- Lowered liver and kidney function
- Tumors in the liver, lungs, GI tract, and brain
Managing Mycotoxin Risks Through Nutrition
Understanding mycotoxin risks by following regional survey results, monitoring ingredients, managing suspect ingredients, and employing mitigation tactics is essential for building productive and profitable operations. Working with your nutrition team to determine the best measures for managing mycotoxins will be key when feeding crops grown in 2019 to livestock. Assistance can include formulation and nutrition solutions. Reach out to your local Cargill Representative or contact us here to learn more about how PROMOTE® additives are part of the nutrition solutions provided by Cargill.