Vigilance Assures Food Safety

By Arden Wohlers DVM
Extension Veterinarian
University of Nebraska Panhandle Research and Education Center

Numerous neurological diseases and conditions affect the brain or other nerve tissue of cattle. The same is true for all mammals including humans. We have often found limited success in treating cattle with these conditions in an economical manner. The diseased animal may die or we may need to destroy it humanely. The threat of Bovine Spongiform Encephalopathy (BSE) has made it increasingly more important to obtain a diagnosis of any neurological condition in cattle by performing laboratory tests on the diseased animal. A correct diagnosis may allow successful treatment of some diseases or prompt the producer to implement procedures that will prevent diseases from spreading through the herd or into neighboring herds. Finding and eliminating diseases such as BSE assures the consuming public of the safety of our food supply.

It is often difficult to differentiate the common neurological diseases that we deal with in cattle because the clinical signs that the animal exhibits are very similar. Diseases that affect the front part of the brain will often cause blindness or behavior changes including depression, coma, or aggressiveness. Examples of these diseases would be rabies, BSE, polio, and lead poisoning. Bovine Virus Diarrhea can infect a fetus at a time when the back part the brain is vulnerable. The back part of the brain is responsible for coordination so along with other symptoms these animals commonly show staggering, tremors and spastic motions. Brainstem infections such as caused by listeria may result in staggering to the side or falling as well as paralysis of various muscles of the face causing inability to blink, chew or maneuver the tongue. Middle ear infections from bacteria can progress to the inner ear and the cow may lose her ability to walk or it may result in her death. Injury, cancer and tetanus will affect the spinal cord causing staggering, paralysis and loss of muscle mass.

Depending on the cause of these conditions, we may be able to treat the animal with antibiotics, use drugs that will reduce inflammation, replace deficient vitamins or minerals and try physical therapy. We are unable to cure some cattle from their neurological disease and we must remove them from our food supply. Any bovine over 30 months of age that dies after exhibiting neurological signs should have a diagnostic post mortem performed and the appropriate tests done to rule out BSE. The Animal and Plant Health Inspection Service leads an ongoing, comprehensive surveillance program for BSE in the United States. This is important to give confidence to our own consumers as well as those in the countries where we export meat. Federal veterinarians with USDA’s Food Safety and Inspection Service, state employed veterinarians with the Bureau of Animal Industry and many private practitioners have received training in the procedure for obtaining the tissue samples needed for testing for BSE. This extensive level of vigilance with the goal of testing 220,000 head of high risk cattle in the next year should assure that we have the safest food supply in the world.

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