When using internal teat sealants:

Use good hygiene practices to avoid pathogens being introduced into the mammary gland
Work with your vet to ensure anyone administering ITS receives thorough training first.

For more information on drying off and preventing mastitis visit dairynz.co.nz/mastitis

Mastitis control is very much front of mind for many of you as you prepare to dry off your cows for the winter.


It's best practice to only use antibiotic dry cow therapy to treat cows that display mastitis symptoms. For other animals, use alternatives such as internal teat sealants to prevent mastitis infection.

Interestingly, research has found that internal teat sealants are just as effective as dry cow therapy. They reduce rates of new infections over the dry period and reduce rates of clinical mastitis in the subsequent lactation.

So, how do you determine which cows need antibiotic dry cow therapy verses internal teat sealants?

The best way to identify which cows need antibiotics is to individually test your herd's somatic cell count, which can be done through a herd test or culture test by a vet.

A good case study is Manawatu dairy farmer Christine Finnigan who used milk testing to take her mastitis control to the next level.

Two years ago, Christine was having to treat up to a quarter of her herd (about 50 cows) with antibiotic dry cow therapy, but this year she's only had to use it to treat five cows.

Christine achieved these results thanks to the support of her local vet who recommended she milk test cows with mid-high somatic cell count to identify the type of bacteria causing the infection and develop a tailored treatment plan based on the results.

She believes it's equally important to target cows with a mid-somatic cell count, which can sometimes "go under the radar" as they pose just as big a risk to infect other cows with Staph aureus, as those with a high somatic cell count.


Christine used internal teat sealants for her whole herd and also followed best management practice in the milking shed to avoid mastitis.

She recommends farmers talk to their vet about the benefits of milk testing as part of their strategy to prevent mastitis.

"If you don't know what's causing it, it's difficult to deal with it. Milk sampling has given us a lot of information that's been really helpful and given us a pathway to reduce our somatic cell count and the use of antibiotics."

She says the milk sampling was relatively inexpensive and saved her money in the long-run.

"Milk tests (through our vet) cost about $10 a sample, whereas the cost of dry cow therapy antibiotics is around $12 a cow. It's worth doing as you'll save around 30 per cent of your cows needing antibiotics. You'll be in no worse a position this year, and in a better position next year.

"Our average bulk SCC used to be around 150,000 cells/ML, which wasn't bad. But we've managed to drop that even lower, to less than 100,000 cells/ML."

• Kate Stewart is a DairyNZ consulting officer based in Palmerston North