Ask The Vet
Bovine Health Watch recently discussed the impact of Mycoplasma on dairy production with David R. Wolfgang, VMD. Dr. Wolfang is a dairy veterinarian at the Pennsylvania State University, University Park, PA, in the Department of Veterinary and Biomedical Science. He is involved in dairy disease field investigations in addition to his responsibilities as an extension veterinarian.
BHW: Would you briefly describe the health and economic impact of Mycoplasma on dairy animals?
Dr. Wolfgang: There are young stock issues where we have calves that are chronically affected with Mycoplasma. These are often very difficult to treat, so many of these get culled at an early age. Another aspect is that some calves, while they don’t exhibit clinical signs, are carriers of the disease. Some of them, as heifers, may carry the organism in their upper respiratory tract for the rest of their lives. This can result in Mycoplasma mastitis in cows, which can be fairly insidious and costly in a dairy herd. So, generally, the economic losses due to Mycoplasma include animals that are culled from the herd, milk production losses from Mycoplasma mastitis and treatment costs.
BHW: How difficult is it to diagnose Mycoplasma?
Dr. Wolfgang: Mycoplasma requires special media and special culture techniques. Mycoplasma can be missed if these special diagnostic techniques are not used.
BHW: How is Mycoplasma prevented and/or controlled?
Dr. Wolfgang: Herds that have a good protocol in place for controlling all contagious mastitis pathogens have fewer Mycoplasma problems. Managers of these herds do a good job keeping the milking parlor clean; they use teat dips; they identify cows early in the milking stream that have an infection. A very good transition program for your cows is also important. If we can pre-vent sick cows during the transition period, we often have fewer problems. That means a good nutrition program and clean facilities with adequate space, among other things.Typically what we see first with Mycoplasma is a pneumonia outbreak, often caused by overcrowded conditions or by stress during the transition period. Once cows have broken with the respiratory form, it lends itself to Mycoplasma mastitis.Feeding waste or discarded milk to heifers is another risk. We encourage people to have a pasteurizer for their waste milk. Properly used, a pasteurizer can minimize the spread of the disease.
Dr. Wolfgang: At risk animals, such as those you might be purchasing for herd expansion, are at a fairly high risk for breaking with Mycoplasma because of stress. I think there’s a real opportunity for using Mycoplasma vaccine prior to moving these animals. It’s sort of like a preconditioning program to have them vaccinated ahead of time.Herds that have had Mycoplasma problems in the past can obtain real benefit from using Mycoplasma vaccines in the heifers. If those heifers going into the transition period are fed a good diet, are healthy and strong and have some immunizations, then when they go into a stress period – having a calf and entering a lactating herd – they can be pretty well protected.I want to get them vaccinated prior to the stress and transition periods so that they have antibodies built up. My basic philosophy is immunizations help, but need to be targeted and used based on risk and reward. Producers should try to think of the herd or farm in a more holistic fashion.I am a big advocate of having a veterinarian work with producers to actually develop an immunization plan or protocol for their specific situation. This plan needs to be based upon what can be done to reduce risk, maximize health and improve overall immune function.