Brain Infection in a Dairy Cow
February 2024

I was called on a Friday afternoon just before Christmas to see a cow that had been slow all day and was now unable to walk straight. She also had a head tilt and appeared blind. The farmer thought this may be ketosis which was plausible to me given the signs, though it would be strange to see it this far into the season.

When I examined the cow, she showed all the signs described by the farmer with the addition of pus leaking from the nose due to a forest’s worth of sticks being stuck up there. She was negative for ketosis as measured on a ketone meter, had a low body temperature (around 36 degrees), slow heart rate and evidence of mild dehydration. The cow was also clearly in a considerable degree of pain as she was grinding her teeth and not reacting to any part the exam including me jamming a finger up her nose.

I made a tentative diagnosis of meningitis(brain infection) secondary to nasal infection from the sticks in the nose and offered a poor prognosis. After discussion with the farmer, it was decided that it was best to put her down as she was in a lot of pain and it would take an aggressive and expensive treatment plan to have even a chance of saving her. I also mentioned that this cow would be eligible for the TSE surveillance program which is a scheme from the MPI offering farmers $250 for brains from cows presenting similar to this so that they can do nationwide surveillance for Mad Cow Disease. I hoped that in taking the brain for this program I might also confirm my diagnosis.

I opened the skull and exposed the brain revealing pockets of pus through its lining with a trail of infection starting deep in the nose - this confirmed my diagnosis. With the sheer amount of pus in the brain I was confident that there was nothing that we could have done, and treatment would have put her through unnecessary suffering.