12 September 1997

Vets idea may raise heat detection rate

KEEN to improve heat detection rates? Then a simple system of milk progesterone testing developed by Glos vet Chris Watson could be worth considering.

It involves taking three milk progesterone samples and should mean that its possible to detect 80% of returns to service, compared with the 50% national average.

Mr Watson of the Wood Veterinary Group, is concerned that progesterone testing is under-used on farms. To encourage uptake he told the conference he was keen to move away from systems that detect oestrus. "The work involved leads to lack of co-operation from the farm staff."

What is needed is a system to aid heat detection – the key to fertility performance, he said. It must be user-friendly enough to give encouragement without causing complication and confusion.

"The simple fact that a herdsperson can be alerted to the possibility of a cow likely to repeat in a period of a few days is extremely valuable," he said.

The system, trialled on two farms, tests three categories of cows: Cows observed in oestrus and to be served (day 0); and cows at day 19 and day 24 after service.

A low reading at day 0 establishes diagnosis of oestrus and the cow is served; a high means inaccurate heat detection and further samples are unnecessary. Key samples are day 19 and 24, said Mr Watson. Low at both tests means heat is likely; high at 19, low at 24 gives a non-predicted return and a high, high result means the cow is pregnant.

Over three-quarters of returns – 77% – were predicted. They showed a low progesterone at day 19. "This information could be used to highlight cows worth observing closely; increased observation and heat mounted detectors could then be used."

As a result Mr Watson suggested it would be achievable and realistic to detect 80% of returns. Conception rate should lift with the better observation, he added.

Use of three progesterone samples at 0, 19, 24 produced a very high accuracy of PD, he said. "Coupled with a later manual PD at days 38-45 post service on the positives – and a system of handling the negative animals, the system helped lift performance. &#42

Glos vet Chris Watson… Use of three progesterone samples coupled with a later manual PD will help lift fertility performance.