Testing for antibiotic identification
With a 12-week dry period recommended for first lactation cows, early-calved first calvers that are due around February 1 again in 2025 need to finish their 2024 lactation in late October/early November.
Consequently, teat sealers and the right dry cow antibiotic (where required) will need to be prescribed and bought in time.
Milk culturing is a process whereby a lab grows the bacteria in the samples you have submitted and assesses the colonies that form to identify the causative agents (Staph. aureus, Strep. uberis or Strep. agalactiae, etc.). Sensitivity analysis, which examines the resistance or susceptibility of the cultured bacteria to a list of antibiotics is the final step to help identify the appropriate treatment for your cows that require antibiotic treatment.
Correct sampling technique
The sampling technique is critical for successful outcomes from culture and sensitivity sampling, as bacteria from the environment, such as your hands or dirt from the cow’s udders or teats, can contaminate the sample, which makes it useless for culture and sensitivity testing. This is a major source of frustration for farmers, so follow these steps:
- Clean, disinfect and dry teats;
- Use disposable gloves and sterile sampling bottles;
- Keep the sample bottle capped until you are ready to take the sample;
- Draw the milk into the sample bottle holding it at a 45o angle to avoid any debris from the udder ending up in the bottle;
- Refrigerate at 4o C or freeze if necessary; and,
- Visit Animal Health Ireland Successful Culture and Sensitivity Sampling for a more detailed description of how to take a sterile sample.
The above article by Dr Joe Patton, Head of Dairy Knowledge Transfer at Teagasc, first appeared in the October Teagasc Dairy Advisory Newsletter. To access the full publication, which includes top five tips and grazing objectives for October, click here.
Also read: How to take a sterile milk sample for culture and sensitivity