Ask the Vet

Neurologic Issues Hard to Diagnose

A calf that falls often can be suffering from a number of issues. A diagnosis can be critical to safeguard the health of the herd. (Progressive Farmer photo by Jim Patrico)


My brother and I penned some calves to sell, one being a 5-month-old heifer. We had to isolate her because the other calves kept knocking her down. Every time she was bumped, she went down, and it took her a couple of minutes to get back up. She did not seem to be able to stand normally, but she walks and runs -- just not like the other calves. It seems like an equilibrium problem. Have you had any experience with this?


Neurologic issues in cattle can be frustrating, especially in a "field" situation. In human medicine, and increasingly in veterinary medicine, we have several diagnostic tools at our disposal. But, those tools are either not possible to use with an animal in a chute, or they are simply cost prohibitive.

CT scans (computed tomography), MRIs (magnetic resonance imaging), lab work, spinal taps and other advanced diagnostics are often needed to figure out these cases in live animals. There are, however, some diseases that could create the situation you describe that can be diagnosed and possibly even successfully treated in the field.

Let's first consider polioencephalomalacia. This is a neurologic disease of ruminants seen worldwide. It can be caused by excessive grain consumption or high sulfur levels in feed or water, but I have seen it in animals on very-good-quality pastures. I have had some success early on in treating this disease with high levels of thiamine (vitamin B1).

Bacterial encephalitis could also be the cause. Listeria and Histophilus somni (Haemophilus somnus) have commonly been implicated, but many bacteria can be involved. Viral encephalitis is another possibility, and rabies has to be considered. Bovine spongiform encephalopathy (BSE) is also on the list. Even head trauma is a possibility since this calf is being bullied. Lastly, toxins could be involved. I have seen several cases of lead toxicity during the years that displayed signs similar to what you describe.

Given there are several scenarios to consider, it is imperative your veterinarian examine this calf as soon as possible. If the calf dies or has to be put down, I recommend a complete necropsy either by your veterinarian or your state diagnostic lab. If for no other reason than the slight risk of rabies, you owe it to yourself and others to rule that out. And while BSE would be far more rare than rabies, as stewards of our animals and the public health, we should be on the lookout for this, as well.