Progesterone test while you milk

Now, a South Canterbury veterinary clinic is trialling the P4 Rapid kits here (see panel).

The test was launched in the UK in September 2012 and manufacturer Ridgeway says sales are already at 500 kits of 25 tests per week: that’s over half a million tests/year.

Uptake has been similarly rapid in other countries, such as Finland where they were selling 400 kits/week four months after launch.

“Many farmers are either on or moving onto one of our Herd Packages which means they get regular deliveries for a much discounted price and based on their calving pattern,” Ridgeway’s Marcus Hollingshead told Rural News.

Most farms’ first use is to confirm dubious bulling behaviour, especially post AI.

“If a cow is seen or monitored apparently bulling after already being inseminated this is a simple cost-effective way of making sure that the cow is ‘open’ and not risking infection, a wasted straw or early foetal death by inseminating a cow that may already be pregnant,” he explains.

Another popular use is 19-21 days after AI to check for return to cycling.

“This is 100% effective. Farmers are wanting to make sure they catch their cows on the very next possible cycle.”

Compared to waiting two full cycles until conventional pregnancy diagnosis it’s a very cost-effective check to ensure no time is lost getting a cow that hasn’t held re-served.

A third use, and one most users come to once they’re used to the product, is to confirm oestrus before insemination.

“This is especially important to users of high cost semen,” notes Hollingshead.

Another use is to check return to cycling post-partum.

“Not necessarily for all second-plus lactation cows but some show no signs – especially if they’re lame or in restrictive/slippery housing.  A weekly test over three weeks on the same day each week will detect anoestrous cows and give a ‘work-from date’ for those cows that are cycling, but not showing.

“Some use that marker and work towards insemination next cycle. Others will test each day from a low indicator and inseminate as soon as.”

The test is also being used on cows diagnosed as pregnant but behaving in a way which makes the farmer believe something’s  not right.

“Low progesterone levels (3-5 ng/ml) continuing after a cow is pregnant are likely to result in re-absorbtion, EFD, or abortion.  A cow previously diagnosed as pregnant but showing 0-1 ng/ml levels of progesterone is definitely no longer in calf.”

While there are other milk progesterone level tests, Hollingshead says P4 Rapid is the only lateral flow milk progesterone test available.

“It is definitely the only five minute ‘cow-side’ test.  It was designed by a dairy farmer’s son, Aaron Bennett, specifically to give farmers quick information that they couldn’t otherwise easily get.

“He wanted it to be a practical, store on a shelf, ambient temperature, use when you want sort of tool: no fridge chemicals etc, just the test and a ¼ inch of well-homogenized milk; not even necessarily clean milk!”