Assessing risks for mastitis and antibiotic use in dairy herds

Measures to control mastitis are fairly well established and known, yet mastitis control is still weak on some farms. Assessing risks for mastitis can help identify where improvements can be made.

The principles and practices of controlling mastitis aren’t new. Nor are they overly complicated. Yet many farms still struggle with mastitis and ship milk with a bulk tank somatic cell count (BTSCC) that indicates the disease is not well controlled in the herd. Frequently, antibiotics are not used in the most strategic manner for managing mastitis cases, resulting in overtreatment (or undertreatment) of infected quarters.

What does it take to consistently achieve a low BTSCC? What are the limiting factors to better mastitis control? How do we make better choices in drug therapy? These are questions being asked by the Quality Milk Alliance (QMA), a group of researchers and Extension professionals from Michigan State
University Extension
, and Penn State, Florida A & M and Mississippi State Universities.

The QMA will be looking at five primary areas that impact mastitis control and antibiotic use:

  • People and routines
  • Milking system
  • Cow and her environment
  • Management of infected cows
  • Management culture

People and routines are the specific steps in the milking routine and the consistency with which those routines are implemented in a timely manner. It also includes the manner in which cows are handled as that can affect their milk letdown.

The milking system is the tool used to harvest milk and maintain its quality, but as is the case with any tool, especially one that is used constantly, timely maintenance of the system, proper adjustment and replacement of worn parts affects the function and the chance that the system will harbor bacteria that can be passed on to uninfected cows.

The cow and her environment factors relate to the housing environment and its impact on the cleanliness of the cow and the potential exposure to bacteria. Therefore bedding type, quality and maintenance of beds, alley cleanliness and cow comfort are important factors. Ventilation and stocking rate may likewise impact exposure to mastitis pathogens.

Management of infected cows is a critical area of a mastitis program, not only because cows may be infected with contagious bacteria that could be spread to other cows, but because infected cows tell us something about mastitis risks in the herd. However, we need to take the opportunity to learn which bacteria are causing infections and when or where cows are becoming infected.

In addition, this is where decisions are made, good or bad, regarding treatment. The use of antibiotics should be reserved for those cases that are most likely to respond favorably to their use. Good udder health records can be an important means of learning which treatments are most successful, as well as helping to avoid residues in shipped milk or meat.

Management culture reflects what is the situation on many farms today, that milking, as well as other tasks that relate to quality milk, are done primarily by non-family employees. How owners and managers train, equip, provide feedback and communicate with employees certainly is related to the performance of those employees. Management that builds the teamwork of engaged employees to achieve goals is the owner’s responsibility. It would be difficult to maintain good milk quality where employees do not take pride in producing quality milk, or when they do not remain on the farm long enough to grow in their knowledge as well as their commitment.

The QMA is developing an evaluation system to accurately identify the highest risk areas for mastitis on a dairy farm, and make meaningful recommendations to address them in a cost-effective manner. The expectation is that if a producer is able to make improvements in these areas, milk quality will improve, and the improvement in udder health will mean less use of antibiotics for a disease for which prevention is the best means of control.

If you would like to learn more about the Quality Milk Alliance or mastitis control, please visit

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