Yeast and Molds: A Practical Summary for Controlling Mastitis

Introduction

Mastitis cases caused by yeast and mold are typically sporadic and are usually not a significant issue in a herd. Yeast form white or cream-colored colonies that can easily be confused with coagulase-negative staphylococci. Gram staining will differentiate yeast from CNS; yeast are two to three times larger than CNS and typically exhibit budding. Mold colonies can have a fluffy texture and exhibit several different colors.

Information in this publication was summarized from the National Mastitis Council’s Laboratory Handbook on Bovine Mastitis (Hogan et al. 1999).

Where are these organisms found?

These organisms are commonly found in soil, plants, decaying organic matter, and most importantly, in contaminated treatment preparations. Bulk bottles of treatments, teat cannulas, and syringes are common sources of yeast and mold.

How do yeast and mold infect the mammary gland?

Yeast and mold will infect the mammary gland through dirty infusions. Sometimes these pathogens will invade the mammary gland from contamination in the environment or possibly from cow to cow during milking when improper procedures are used.

How can you prevent and control mastitis caused by yeast and mold?

The prevention of yeast and mold mastitis starts with aseptically infused intramammary preparations. When infusing the mammary gland with a mastitis treatment or at dry off with a dry cow therapy product, ensure that teats are clean and dry. After the udder is milked out, use a separate alcohol wipe for each teat. Scrub each teat thoroughly until clean. Infuse the teat with a single-dose sterile tube or cannula. Do not reuse teat cannulas or tubes. Consider only inserting the teat cannula partially into the teat canal.

Additionally, proper medical treatment to injured teats will help to minimize infection. Stripping out infected quarters and proper sanitization of milking equipment will reduce exposure.

When are yeast and mold mastitis infections most likely to occur?

Most yeast and mold infections occur during treatment of another mastitis pathogen due to a dirty infusion.

How likely is a yeast or mold infection to be cured?

Antibiotic therapy is NOT recommended for yeast or mold mastitis because it can worsen the clinical signs of mastitis. While most yeast or mold infections will spontaneously cure within two months, the infections that are not cured will typically result in culling.

Quick Notes

• Yeast and mold mastitis cases are typically caused by dirty infusions.
• Aseptic infusions and single-dose sterile intramammary tubes should be used to prevent the introduction of yeast and mold into the mammary gland.
• Antibiotic therapy is not recommended for the treatment of yeast or mold infections.
• Most yeast/mold mastitis will spontaneously cure within two months. The cases that do not cure typically result in culling.
• Proper milking procedures, medical attention to any teat injuries, and proper sanitation of milking equipment should prevent yeast and mold mastitis.

References

Hogan, J. S., R. N. Gonzalez, R. J. Harmon, S. C. Nickerson, S. P. Oliver, J. W. Pankey, and K. L Smith. 1999. Laboratory Handbook on Bovine Mastitis. Madison, WI: National Mastitis Council.