Drying off for a number of first lactation cows and thin cows should be only a matter of days away and milk culturing should be carried out to identify the bacteria lingering on the farm.
With a 12-week dry period recommended for first lactation cows, the end of the 2024 lactation draws near for early-calved first calvers that are due around February 1.
This means that there is not a lot of time to get teat sealers and the right dry cow antibiotic for your herd bought in time.
Blanket dry cow therapy is a thing of the past and the use of selective dry cow therapy (SDCT) is now required on cows, but others are still going to need an antibiotic at dry off.
Getting a culture and sensitivity test is a good idea ahead of drying off, as it provides you with a better understanding of the bacteria you have to deal with on your farm.
Milk culturing
Milk culturing is the process where a lab grows the bacteria in the samples you have submitted and assesses the colonies that form to identify the causative agents.
The causatives agents are generally staph, aureus, strep, uberis or agalactiae, along with others that can cause issues on farm level.
A sensitivity analysis then examines the resistance or susceptibility of the cultured bacteria to a list of antibiotics to see the effectiveness.
This is the final step to help identify the appropriate treatment for your cows that require an antibiotic treatment.
The success of milk culturing and sensitivity analysis is completely determined by the cleanliness of the sampling technique as bacteria from the environment, such as your hands or dirt from the cow’s udder or teat can contaminate the sample.
If the sample gets contaminated, then it is useless and a waste of time, so a strategy to successfully harvest the milk sample should be implemented.
The following steps should be taken:
- Clean, disinfect and dry teats;
- Use disposable gloves and sterile sampling bottles;
- Keep the sample bottle capped until you are taking the sample;
- Draw the milk into the sample bottle holding it at a 45° angle to avoid any dirt from the udder going into the bottle;
- Refrigerate at 4℃ or freeze the sample if necessary.
A culture and sensitivity test takes 48 hours and it is then tested, which takes a further 12 hours. In total, test results will take three days.
The test should give you a better picture of the bacteria causing mastitis/cell count issues on your farm and you can then (with the consultation of your vet), select the antibiotics that will work best in your herd.
Not every cow needs to be tested, but more than one cow should have a sample taken in order to ensure accuracy.