Milk  Collection Guidelines for Bovine Mastitis Culture

The Diagnostic Services Bacteriology Laboratory can only test samples collected from individual or compost quarter samples and cannot test bulk tank milk samples. For the best possible results from the laboratory, take samples directly from the cow using the aseptic technique as outlined by the National Mastitis Council (click here for reference). Do not take samples via the milking equipment or weight meter. For more information on milk collection and bovine mastitis culture, please contact the laboratory at 902-566-0821.

Please Note: Laboratory fees will be applied regardless of whether clean or contaminated samples are submitted.


Materials for Aseptic Milk Collection

• Sterile vials or tubes
• 70% alcohol (ethyl or isopropyl)
• Cotton balls or gauze soaked in 70% alcohol, or commercially prepared, individually packaged alcohol swabs
• Cooler with ice or freezer packs for storing samples
• Racks for holding sample tubes or vials while sampling cows, and for cooler storage
• Disinfectant for cleaning teats (effective germicidal products used for pre-milking teat disinfection are recommended)
• Paper towels or individual cloth towels
• Means of identifying samples: permanent ink pen (with ink that is stable in both water and alcohol) or typed labels

Aseptic Milk  Collection Technique

  • Label tubes prior to sampling (date, farm, cow, quarter).
  • Brush loose dirt, bedding, and hair from the udder and teats. Thoroughly wash and dry grossly dirty teats and udders before proceeding with sample collection. Udders should be washed as a last resort.
  • Discard several streams of milk from the teat (strict foremilk) and observe milk and mammary quarters for signs of clinical mastitis. Record all observations of clinical signs.
  • Dip all quarters in an effective pre-milking teat disinfectant and allow at least 30 seconds contact time.
  • Dry teats thoroughly with an individual towel.
  • Beginning with teats on the far side of the udder, scrub teat ends vigorously (10 to 15 seconds) with cotton balls or gauze moist (not dripping wet) with 70% alcohol. Teat ends 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 ends. Avoid clean teats coming into contact with dirty tail switches, feet, and legs. In herds where cows are not cooperative, begin by scrubbing the nearest teat until clean, obtain the sample, and move to the next teat. • Begin sample collection from the closest teat and move to teats on the far side of the udder. Remove the cap from the tube or vial but do not set the cap down or touch the inner surface of the cap. Always keep the open end of the cap facing downward. Maintain the tube or vial at approximately a 45 degree angle while taking the sample. 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.
  • To collect a composite sample (milk from all four quarters in the same tube), begin sample collection with the nearest teats and progress to the teats on the far side of the udder. One to 2 ml of milk should be collected from each quarter of the udder.
  • 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.

Laboratory Submission Guidelines

  • Please include a listing of all cows sampled and the teat(s) collected on the sample submission. Attaching a separate sheet with this information is acceptable.
  • Please state whether or not the samples had been frozen.
  • Ensure submission form and sample identifications are kept in a plastic bag to avoid getting wet.