MOLDY GRAINS, MYCOTOXINS AND FEEDING PROBLEMS

Introduction

Aflatoxins

Zearalenone

Trichothecenes (DON, T-2)

Fumonisins

Ochratoxin

Preventative Practices

Detrimental Feed Concentrations

What is ppm & ppb?

Plant Disease Associations

Links

 

TRICHOTHECENES

 

Trichothecenes are a large group of toxic metabolites that are produced by many Fusarium species. Toxins of importance to livestock and poultry producers are T-2 toxin and deoxynivalenol .  

 

Most animals refuse to consume feeds with high concentrations of trichothecenes, resulting in loss of weight.

    

Deoxynivalenol  (DON)

 

Crops and Weather Conditions

 

Deoxynivalenol (DON), also known as vomitoxin, is produced by Fusarium graminearum (Gibberella zeae) on corn and wheat prior to harvest as well as during storage. Both Gibberella ear rot of corn and Fusarium head scab of wheat are common diseases. 

 

Impact on Animal Health

 

DON causes extensive feeding problems in swine.  

  • Clinical signs associated with consumption of a DON- contaminated diet by hogs are vomiting and feed refusal, followed by loss of body weight

  • Diets containing 12 ppm, when consumed, provoked vomiting after 15 minutes.

Poultry are also susceptible to DON.  

 

Beef cattle tolerate DON in feed at approximately 10 ppm in the ration.

 

Guidelines for Grain Use

 

 
Deoxynivalenol / Vomitoxin

FDA Advisory Level Concentration at which regulatory agency urges caution
Humans - Wheat, Barley (finished products)   1 ppm
Cattle and chickens (all grains) 10 ppm, not to exceed 50% of diet 
Swine (all grains)   5 ppm, not to exceed 20% of diet 

 

T-2 Toxin

 

One of the most potent mycotoxins of the trichothecene group, T-2 toxin, is produced in feedstuffs by several Fusarium species.  

 

Crops and Weather Conditions

 

T-2 toxin is produced over a wide temperature range, with maximum production occurring below 59° F. No T-2 toxin is formed above 90° F.

  

Corn that is high in moisture content and stored in conventional corncribs without artificial drying frequently becomes “moldy” and is at risk of developing T-2 toxin problems.

 

Impact on Animal Health

 

All farm animals are, to some extent, susceptible.

  • General symptoms in cattle are bleeding (uncontrollable, at times, during castration or dehorning), inflammation of the digestive tract, vomiting, diarrhea, decrease in milk production, loss of appetite and feed refusal.

  • T-2 toxicosis epidemics also pose a threat to the poultry industry. Clinical symptoms of T-2 toxicosis in poultry are the appearance of lesions on the mouth and tongue that impair eating.

  • Frequent defecation, vomiting, loss of weight and feed refusal are some of the signs associated with T-2 toxicosis in swine.