Dr. Warren Bohnhoff, DVM

Recently, the personnel at ANC had the opportunity and privilege of hearing Dr. Neil Forsberg of Oregon State University. He presented facts indicating a mold, Aspergillus fumigatus (AF) is capable of infecting the ruminant GI tract and causing hemorrhage. Primary avenues of entry for mycotic infection in ruminants include the abomasum and Peyer's patches of the small intestine. Several pathogenic fungi can affect ruminants, but A. fumigatus has been detected by DNA analysis in this disease.

Predisposing factors for mycotic infections in ruminants include:
   Feeding of moldy feed
   Immuno-compromising diseases
   Acidosis
   Anti-microbial therapy
   Reflux of abomasal contents
   Metabolic disturbances
   Post-partum stress
   Viral disease such as IBR and BVD
   Anti-inflammatory treatment
   Abortion

Interestingly, A. fumigatus is a virulent pathogen in immunosuppressed human patients, a condition similar to a highly-stressed lactating cow.

Stressors in lactation include:
   High starch diets (and potential acid reflux)
   Ketosis
   Milk fever
   Laminitis
   Rough handling
   Poor cow comfort
   Poor feeding practices
   Social isolation when sick animals are placed in a "hospital pen"
   Estrus and artificial insemination

When these occur, immunosuppression is a common result and underlies the morbidity associated with this disease.

In previous years, the bacteria Clostridium perfringens was thought to be the primary etiologic agent. While C. perfringens toxin genes alpha and epsilon were detected, they were not detected in all Jejunal Hemorrhagic Syndrome (JHS) cows. Also, some healthy cows tested positive for C. perfringens beta-toxin gene. Thus, JHS correlated with infection by A. fumigatus. The disease in cattle appears to be similar to aspergillosis in humans.

Dr. Forsberg then formulated a product, Omni-Gen AF™, based on its ability to inhibit fungal growth and tested it in the field. The trial involved 1,700 cows in herds which had experienced an incidence of mycotic abortions, JHS or both. The product successfully prevented occurrence of both mycotic abortions and JHS. Omni-Gen AF™ is now marketed by Prince Agri Products, Inc. and is available from Agri-Nutrition Consulting, Inc. Even though you may not have had any mortality, but A. fumigatus has been detected in feeds, feeding for prevention is a sound management decision.

Preventative measures:
   Follow best management practices for proper storage of feed ingredients and ensiled forages.
   Do not feed moldy feeds, especially to pregnant or milk producing animals.
   Feed a ration that avoids conditions conducive to acidosis.
   Have a veterinarian routinely conduct autopsies on cows suspected of having JHS.
   Submit blood samples for analysis of A. fumigatus if suspecting mycotic abortions or JHS.
   If possible, feed products that reduce susceptibility to A. fumigatus growth.

Mold problems are on the increase, partly due to feeding more fermented feeds, improperly ensiled or stored feeds, and no-till farming, thus allowing molds to proliferate amid surface organic matter.

If this problem exists in your herd, a test kit can be obtained by contacting your ANC consultant.