Sterile milk sampling for bacteriology

When clinical mastitis has been diagnosed in a quarter, a sterile milk sample should be taken to determine which bacteria is responsible. This will help with implementing specific mastitis control measures. Cows should be sampled as soon as mastitis is detected, preferably before milking is commenced.

1: Clean disposable gloves must be worn. Use a separate pair for each cow.

2: If teats appear clean, go straight on to step 3. If teats are obviously dirty then clean off dirt from teats only (avoid getting udder wet) with clean running water from the in-line hose, then dry wipe teats completely with a disposable paper towel.

3: Dip teats in a rapid-acting predip (As shown in figure 1.), then dry wipe. Strip fore milk (3-4 draws).

4: Thoroughly disinfect the whole surface of the teat with a disposable spirit / alcohol soaked swab. As shown in figure 2.

5: Gently scrub only the teat ends with an individual disposable spirit / alcohol swab, using fresh swabs if necessary until both teat and swab are clean. It is most important to use a new swab for each teat. If sampling more than one teat per cow, clean the teats furthest away from you first, to avoid contaminating cleaned teats. As shown in figure 3.

6: Take a sterile pot and carefully remove the lid, taking care not to contaminate the pot or lid. When taking the sample incline the pot to 45° (as this will reduce the chance of dirt falling into the pot). Only a few ml are required for a useful sample. Remember the longer the lid remains off, the greater chance of contaminating a sample.

7: Record cow ID, quarter sampled and date of sampling on the tube.

8: After sampling, appropriate treatment should be administered in accordance with veterinary advice.

9: Samples should be stored appropriately until being sent to the lab (either refrigerated if sample is being sent to the lab within 24 hours, or frozen with glycerol if not being sent within 24 hours).