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 |
4.6%
|
3.9% |
4.5% |
4.3% |
- high |
13.9%
|
7.6%
|
7.3%
|
8.6%
|
- low |
1.2% |
0.4%
|
1.5%
|
1.2%
|
% new mastitis monthly - average |
2.6%
|
2.4%
|
2.5%
|
2.5%
|
- high |
5.4%
|
3.9%
|
3.8%
|
4.2%
|
- low |
0.8%
|
0.4%
|
1.1%
|
1.1%
|
% new mastitis of total - average |
64%
|
56%
|
59%
|
61%
|
- high
|
89% |
66%
|
80%
|
83%
|
- low |
22%
|
39%
|
26%
|
33%
|
total somatic cell monthly - average |
288 |
272
|
300
|
279
|
- high |
405
|
549
|
539
|
611
|
- low |
113
|
130
|
132
|
109
|
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. |