NMC responds:
An important part of a mastitis control program includes microbiological analysis of milk from cows that have mastitis or are suspected of having mastitis.

Culturing milk samples allows for the identification of the organisms causing the mastitis.

This information is critical for understanding specific herd problems, for applying preventative management programs and for developing treatment programs.

Proper technique in collecting the milk sample is essential. Strict aseptic procedures must be followed to avoid contaminating the milk with bacteria present on the skin of the cow, hands of the sampler and barn environment.

Procedure for taking an individual quarter sample:

• Use sterile single-use tubes with tight-fitting caps.

• Label tubes prior to sampling (date, farm, cow, quarter) with a permanent marker.

• Brush loose dirt, bedding and hair from the udder and teats. Teats and udders that are extremely dirty should be washed and dried before taking a sample.

• Discard several streams of milk from the teat to be sampled to remove contaminated milk from the teat end.

• Dip quarter in an effective premilking teat disinfectant and allow at least 30 seconds contact time.

• Dry teat thoroughly with an individual towel.

• Scrub teat end vigorously (10 to 15 seconds) with cotton balls or swabs moistened with 70% alcohol. Teat end should be scrubbed until no more dirt appears on the swab or is visible on the teat end. A single cotton ball or alcohol swab should not be used on more than one teat. Take care not to touch clean teat end. Avoid clean teat coming into contact with dirty tail switches, feet and legs.

• Remove the cap from the tube. Do not set the cap down or touch the inner surface of the cap to avoid contamination. Always keep the open end of the cap facing downward. Hold the tube at an angle while taking the sample so that debris does not fall into it. Do not allow the lip of the sample tube to touch the
teat end.

• Collect one to three streams of milk and immediately replace and tightly secure the cap. Do not overfill tubes, especially if samples are to be frozen.

• When samples are taken at the end of milking or between milkings, teats should be dipped in an effective germicidal teat disinfectant following sample collection.

• Store samples immediately on ice or in some form of refrigeration. Samples to be cultured at a later date (more than 48 hours) should be frozen immediately.

If more than one quarter from an individual cow is going to be sampled, the teats on the far side of the udder should be cleaned and disinfected first, followed by the teats on the near side. Sample collection should be the reverse order; starting with the near teats first, followed by the teats on the far side of the udder.  EL