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Doc's Corner Article 113

April 17, 2006

Is Mastitis a Problem? How great is the problem of mastitis?

“What are normal mastitis levels within a dairy herd?” or better yet, “What are acceptable mastitis levels in well managed dairy operations?”

Ask any Mastitis Consultant, Dairy Practitioner, Mastitis Drug Salesmen or Dairyman and observe the varying answers or most likely no answer you might receive. It is difficult for me to believe that many who attempt to aid the dairyman in controlling this very costly disease lack the straight answer as to what one might expect under varying milking management conditions. Many years ago, I was of the opinion that given a dozen dairies without apparent mastitis problems and a dozen with serious mastitis problems that I could monitor on a monthly basis, I would find the answer to solving this long time major disease in the dairy industry. Unfortunately, after many years of effort, I cannot honestly say that if you persist in correcting the many so-called causes of mastitis that the problem will be solved. There are many ways in which one can lower somatic cell levels and minimize the numbers of mastitis, but none that really solve the problem. There are many dairies that have minimal mastitis problems and at the same time many that have extreme mastitis problems, but even with these comparisons, there is no clear answer as to how to completely correct the problem.

Ask the question as to what might be considered abnormal or high levels of mastitis and you might hear from 2% to 10% monthly. Ask what might be considered a good goal and you could well hear about 1% monthly. Many avoid answering because they know that if all mastitis cases were to be recorded, the % of reported mastitis cases would be much higher.

In attempting to analyze the situation, one must define mastitis. For now let’s consider any clinical case to be abnormal milk, either watery or thickened to form clots or garget. Lets consider any animal that has a California Mastitis Test (CMT) plus 3 to be a treatable case of mastitis, but at same time remembering that most animals with gram negative organisms within the quarters will self-cure, depending upon severity of infection. Mastitis cases that repeat after 21 days should be considered another event while cases that repeat weekly should be recorded as the same event. It is my opinion, that all cases of mastitis must be recorded whether treated or not, on a monthly basis. Cases of mastitis immediately sold or animals dying from mastitis must be recorded as mastitis animals. It is generally assumed that all cows dried are treated for mastitis but not recorded as such.

A recent article in “Hoards Dairyman” by Pam Ruegg suggests that specific procedures directly relate to the incidence of mastitis on a monthly basis:

- written milking routine 5.0% mastitis, no written routine 7.1% mastitis
- complete milking procedures 5.5% mastitis, no procedures 10.3%
- fore-stripping 5.8% mastitis, no fore-stripping 9.4% mastitis
- no training frequency 9.6% mastitis, frequently 5.8% mastitis

The above information must have supporting data to make the statements as to levels of mastitis after initiating suggested improvements. In all my efforts over many years, I have never been able to initiate those procedures with the level of success as suggested. Another article in “Hoards” recently suggested that 10% clinical cases per month to be rather common.

The mastitis data recorded by the participants in my mastitis program are animals with any abnormal milk - this is the agreement, but one cannot always be certain this to be a fact. Total mastitis per month includes new cases and all repeat cases during the current lactation.

Total mastitis per month includes new cases and all repeat cases during the current lactation. My attempted goal is to reduce the new cases monthly along with the objective of adequately treating each case of mastitis to minimize monthly repeats within the herd. It has been my observation that use of the CMT on all fresh and clinical cases of mastitis greatly enhances the ability of reducing level of repeat cases and at the same time lessening the numbers of clinical cases during the 15-90 day period of production after freshening.

Data accumulated over the past several years from roughly 20 to 25 dairies have shown the following:

Year 2003 2004 2005 2006
% total mastitis monthly - average
3.9% 4.5% 4.3%
 - high



- low 1.2%


% new mastitis monthly - average



 - high



- low



% new mastitis of total - average




- high


- low



total somatic cell monthly - average 288


 - high



 - low




My opinion is that the dairies in my projects are dairymen that understand mastitis and are making determined efforts in attempting to control the disease. In many situations mastitis seems relatively easy to control but in others very difficult to lower the incidence of clinical cases. Even though high levels of persistency exists, often one is very concerned about the often lack of complete management for the full 24 hours of the milking operation.

Based upon my observations, one could easily expect mastitis levels to be in the 10% plus range per month on many of the dairies that are less concerned or fail to keep accurate mastitis records. As prices of milk become lower and lower, many dairymen will see that many dollars can be potentially saved by instigating improved milking management and control procedures to minimize somatic cell and mastitis levels.

No effort in mastitis control will be successful unless the dairyman completely understands the problem and has an extremely high level of determination and persistency.

Doc's Corner is a contribution of Lionel H. Brazil, DVM (1928-2007). Dr. Brazil offered dairy consultation services worldwide for many years. His services covered the following areas: milking management, vacuum system evaluation; and all management procedures relating to mastitis control and SCC reduction.



 Copyright© 2010 L. J. Engineering, Inc. All rights reserved. Revised: June 8, 2010