Producers who mix up “home-brewed” antibiotics to treat cows for mastitis may find their herds infected with yeast mastitis as well, says Ralph Farnsworth, veterinarian at the University of Minnesota. Dirt on the tube or on the teat end often gets pushed up into the teat canal, causing a yeast infection.

Yeast organisms produce mastitis with clinical signs similar to coliform mastitis, including hard, swollen quarters and a fever greater than 106 F. However, animals with yeast mastitis will keep eating — a difference from coliform mastitis. Veterinarians recommend culturing suspected cases. Once identified as yeast-infected, give cows time to self-cure, because they don’t usually respond to antibiotic therapy. Most infections will pass in a week or so.

Yeast mastitis doesn’t occur very often — Virginia Tech research suggests around 8.5 percent of cultures show yeast mastitis — yet knowing about it and culturing can save you money in unnecessary treatment cost and discarded milk.

Your veterinarian is learning more about yeast mastitis in the March 2001 issue of Bovine Veterinarian, a sister publication of Dairy Herd Management. Ask him about it.