Recently, I was called to treat a valuable replacement dairy heifer which had become acutely lame. The client was convinced it was broken, such was the level of discomfort that the calf was in. Luckily, or so I thought at the time, the leg was fully intact, but the left hind hock joint was displaying extreme tenderness. The calf was put on a course of antibiotics and some pain relief.

Five minutes after leaving the farm, I received a call on my mobile from the same client enquiring had I gone far.

Luckily it was only a milk sample he wanted me to take back to the lab for mastitis culture and sensitivity testing. I duly drove back for the sample from a cow with mastitis in two quarters that was proving stubborn to the farmer’s usual array of trusted mastitis tubes.

I attended a few more farms that night and when I finally returned to the clinic, I noticed something strange with the milk sample. It didn’t look like the usual milk sample that would be sent in to us.

This sample seemed to have settled out and resembled a sample of dirty water where the bottom of the sample tube contained what looked for the most part like sand or grit. Such was the unusualness of this finding that the sample was sent to the Central Veterinary Research Laboratory Backweston.

A few days later the results were confirmed and mycoplasma bovis had been cultured from the sample.

On talking to my client, I discovered that this cow had mastitis a week or so and that he had been feeding the waste milk to a pen of late calves, which included the calf with the joint ill. Not only that, but a second calf had also developed joint ill.

I advised him to stop treating the mastitis cow and to dry her off for culling and not to use her milk any more. A bulk milk sample was taken to see if there were further positives in the milking herd.

Mycoplasma bovis can cause pneumonia, joint ill/arthritis and mastitis among other symptoms. It has become more apparent over the last few years and is something that should be discussed with your veterinary surgeon, especially where mastitis problems are difficult to cure.