Fusarium mold thrives in cool, humid conditions—temperatures of 69°F or lower and relative humidity above 70%. Among Fusarium species, Fusarium graminearum is notably responsible for producing vomitoxin, also known as deoxynivalenol (DON), and is a leading cause of gibberella ear and stalk rot in corn. Vomitoxin is a type B trichothecene mycotoxin found in grains such as corn, wheat, barley, oats, and rye.
FDA Guidelines for DON in Feed and Food
The U.S. Food and Drug Administration (FDA) has established advisory levels for DON concentrations in grains to ensure food safety for humans and animals:
- Human consumption: Maximum of 1 ppm DON in grains.
- Animal feed (88% dry matter basis):
- 10 ppm DON in grains and grain by-products for ruminating beef cattle over four months old.
- 30 ppm DON in distiller grains, brewer grains, and gluten feeds/meals.
- Total mixed ration (TMR) should not exceed 10 ppm DON.
Research on Feeding DON-Contaminated Grains to Cattle
Several studies conducted between the 1980s and 1990s evaluated the effects of feeding DON-contaminated grains to feedlot cattle. The findings consistently showed no adverse impacts on cattle health or performance, even at higher DON concentrations.
- University of Nebraska
- Feeding diets with 0 to 10 ppm DON to steers and heifers for up to 142 days revealed no differences in average daily gain (ADG), dry matter intake (DMI), or feed-to-gain ratio (F:G).
- North Dakota State University
- Barley diets with DON concentrations up to 12.6 ppm in the finishing phase showed no differences in ADG, DMI, F:G, or carcass characteristics.
- Heifers fed 10 to 15 ppm DON barley diets during gestation and lactation showed no effects on ADG, DMI, or calf birth weight.
- University of Minnesota
- Diets with up to 21 ppm DON in barley fed to feedlot steers for 135–144 days had no negative effects on ADG, DMI, F:G, or carcass traits.
Key Takeaways
- Cattle Tolerance to DON: Feedlot cattle can tolerate diets with DON concentrations as high as 21 ppm without adverse health or performance effects. The rumen’s diverse microbiome can degrade DON into less toxic compounds, mitigating its harmful effects observed in other species, such as swine.
- Practical Implications: Feeding DON-contaminated grains to beef cattle provides a viable alternative to crop loss. However, the acceptance levels of contaminated grains vary among grain elevators, so it’s essential to confirm requirements.
- Research Gaps: Limited data exist on the maximum DON tolerance levels in cattle, emphasizing the need for further studies to refine feeding guidelines.
Feeding DON-contaminated grains or silages to cattle destined for slaughter represents an efficient use of otherwise compromised crops, aligning with sustainable and economically viable feedlot practices.
