Despite the fact that you have done a good job of getting a handle on contagious mastitis pathogens like Staph. aureus, mastitis remains one of the most costly diseases to the U.S. dairy industry, Pam Ruegg, University of Wisconsin veterinarian and milk quality specialist told audiences at the NMC Regional Meeting in Grand Rapids, Mich.

That’s because environmental pathogens now cause many of the problems on dairies. These pathogens often trigger an immune response with mild to moderate clinical symptoms.

The challenge to dealing with these pathogens is some have become more host-adapted and may present as mild clinical cases that erroneously appear to be resolved when the case has actually returned to a subclinical state, says Ruegg. Other environmental pathogens are truly opportunistic and the cow’s immune response successfully eliminates them after a brief period of mild clinical disease.

“Both scenarios make it very difficult for producers and veterinarians to discern the success of mastitis treatments,” she says.

To help improve the odds of success, Ruegg recommends that you do not treat every case the same and she strongly encourages the use of milk cultures to determine what you are dealing with. “You must know the pathogen causing the problem,” she says. The probability of a cure depends on pathogen characteristics.

In addition, she says that you must realize that not every case has the same probability of a cure. While some cases occasionally experience spontaneous cure, the therapeutic cure rate for several mastitis pathogens, like yeasts or mycoplasma, are essentially zero, regardless of treatment.

Factors influencing treatment outcomes include: cow age, stage of lactation and whether she has had a previous case of mastitis, as well as pathogen, duration of therapy and so on.

Therefore, Ruegg notes that it is vitally important for farmers to keep good records and monitor the outcomes of clinical mastitis cases. And it is essential to involve your veterinarian in the developing and evaluating treatment protocols for clinical mastitis.