D100
California Mastitis Test (CMT)
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| California
Mastitis Test. |
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The California Mastitis Test (CMT)
is a rapid, accurate, cow-side test to help determine somatic cell counts (SCC)
in a specific cow. The test was developed to sample individual quarters to
determine the presence of subclinical mastitis. A cow with subclinical mastitis
does not have abnormal looking milk or other clinical signs such as a swollen or
painful udder. The test can also be conducted on bucket and bulk tank milk
samples to help determine somatic cell counts (SCC) of the entire herd.
How to Perform the Test: (See figures 1-5.) A small sample of milk
(approximately ½ teaspoon) from each quarter is collected into a plastic paddle
that has 4 shallow cups marked A, B, C and D. An equal amount of CMT reagent is
added to the milk. The paddle is rotated to mix the contents. In approximately
10 seconds, read the score while continuing to rotate the paddle. Because the
reaction disappears within 20 seconds, the test must be read quickly.
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| Figure 1 |
Figure 2 |
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| Clean
each teat with alcohol. |
Squirt
a small amount of milk from each quarter into the appropriate
quadrant of the paddle. |
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| Figure 3 |
Figure 4 |
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| 1/2
teaspoon of milk is sufficient. |
Mix
an equal ratio of reagent to milk. |
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Figure 5
| Read
and record the results. |
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How to Read the Results: The
CMT reagent reacts with the white blood cells and the mixture thickens or gels
in proportion to the amount of infection present. To become accurate and
consistent, practice this test on cows with a known SCC.
| CMT
Score |
Average
Somatic Count
(Cells per milliliter) |
Description
of reaction |
| N (negative) |
100,000 |
No thickening, homogeneous. |
| T (trace) |
300,000 |
Slight thickening. Reaction
disappears in 10 seconds. |
| 1 |
900,000 |
Distinct thickening, no
gel formation. |
| 2 |
2,700,000 |
Thickens immediately, begins to
gel, levels in the bottom of cup. |
| 3 |
8,100,000 |
Gel is formed, surface elevates,
with a central peak above the mass. |
Treatment: Refer
to the mastitis information found on page F500.
