Aseptic Milk Sampling for Bacteriology Year Group: BVSc1 + Document number: CSL_F02
Equipment for this station: Equipment list: Cow model (fitted with milking udder) Wet wipes Paper towel Teat dip bottle Bottle of surgical spirit Cotton wool swabs Sterile sample pots (tubes) Gloves Marker pen Labels Considerations for this station: The same teat preparation technique is used: To take a sterile sample for bacteriology For intra-mammary infusion For dry cow therapy including teat sealant To take a sample for a California Milk Test (CMT) If practising with the Clinical Skills Lab (CSL) model cow: Place paper towel on the floor to catch any liquid spills Note: The surgical spirit in the bottle has been replaced with water to prevent damage to the rubber teat Sample pots are re-used in the CSL so are not sterile When sampling from a cow, ensure she is aware of your presence as you near the udder e.g. run hand down flank. Anyone working in the Clinical Skills Lab must read the CSL_I01 Induction and agree to abide by the CSL_I00 House Rules & CSL_I02 Lab Area Rules Please inform a member of staff if equipment is damaged or about to run out.
Clinical Skills: 1 2 3 A sample is taken from the affected quarter. If sampling more than one quarter, each sample is taken into a separate pot and must be clearly labelled i.e. the cow s identification, the date and the quarter being sampled. Wear a clean pair of disposable gloves. Wash excessively dirty teats with clean water. Wipe the teat dry with a clean paper towel. Steps 1 and 2 are only required when working with live animals NOT when practising in the Clinical Skills Lab (CSL). Dip (or spray) the teat with a suitable disinfectant pre-dip and allow 30 seconds contact time. Please note: If practising in the CSL the dip is empty. 4 5 6 Wipe the teat dry with a fresh clean paper towel. Discard 10-15ml of milk by stripping (i.e. draw 3 to 4 good strips of milk). If practising with the CSL model cow, please place some paper towel on the floor to catch the liquid. Apply surgical spirit to a cotton wool swab. If practising in the CSL, the surgical spirit has been replaced with water to avoid damage to the rubber teat.
Clinical Skills: 7 8 9 Disinfect the teat end by thoroughly cleaning (scrubbing) with the swab, working from the centre of the teat end (orifice) outwards. Allow to dry. Discard 10-15ml of milk by stripping (i.e. draw 3 to 4 good strips of milk). If practising with the CSL model cow, check that there is some paper towel on the floor to catch the liquid. Disinfect the teat end again by thoroughly cleaning (scrub) with a fresh surgical spirit swab; working from the centre of the teat end (orifice) outwards. Allow to dry. Do not touch the teat again with unclean hands or gloves. If any dirt is splashed onto the udder, repeat the previous steps before progressing any further. 10 11 12 Remove sample pot lid and hold in the palm of your hand with the lid top facing upwards so that the inside of the lid remains clean. Collect a sample by stripping milk from the teat 4 times into the collection pot, which should be held as horizontally as possible to help prevent any dirt falling into the pot from the cow s skin and coat above. Put the lid on immediately and label. Label the tube with the cow s identification, quarter being sampled and the date. In the CSL use one of the sticky labels, write the details on a label with the marker pen and then apply to the tube.
13 14 Clinical Skills: Teat dip with the postmilking teat dip solution and allow to dry. If practising in the CSL, use the pre-milking dip (as is also often the situation on farms). If sampling more than one quarter, repeat all the steps for each teat and use a separate tube for each quarter to be sampled.
Resetting the station: 1. Check that the tank in the milking cow still contains water. If empty please report to a member of the CSL team or write a note on the white board in the CSL. 2. Wipe the teats clean with a wet wipe. 3. Mop up any water on the floor with a paper towel. 4. Dispose of used towels and swabs in the bin. 5. Empty the sample pot and replace in the box. 6. Replace all equipment in the box/cupboard. Station ready for the next person: Please inform a member of staff if equipment is damaged or about to run out.
I wish I d known: Aseptic milk sampling is essential when bacteriology will be undertaken to avoid culturing organisms contaminating the milk sample e.g. from dirt on the skin, rather than those present in the udder and likely to be causing disease. Sampling is best done in the parlour after milking. Ensure the cow is aware of your presence. Cows can kick so be careful where you put your arms. Samples should be stored in a fridge and sent to the laboratory as soon as possible (within 24 hours). If it is likely to be more than 24 hours before sample/s are sent in the post, the sample/s can be put in the freezer. The sample pot lid should be secured with tape. There are useful AHDB guides to: i) Aseptic Milk Sampling https://dairy.ahdb.org.uk/resources-library/technical-information/healthwelfare/parlour-guide-taking-an-aseptic-milk-sample/ ii) California Milk Test (CMT) https://dairy.ahdb.org.uk/resources-library/technical-information/healthwelfare/parlour-guide-performing-a-california-milk-test/ The CMT is used to indicate the somatic cell count of the milk in each quarter. If needing to bend down to take a milk sample: never kneel, always crouch. You can then move away quickly if necessary to avoid getting kicked.