29 September 1995

Progesterone tests pay

HEREFORDSHIRE dairy farmer Hugh Black has reduced his vet bills since using milk progesterone tests to identify cows not cycling post-calving.

He has been monitoring milk progesterone levels on his 69ha (170-acre) Wharton Bank Farm, Leominster for the last five years and in that time has improved heat detection rates by 30%.

He samples his 130-cow mainly summer calving herd on a weekly basis post-calving and tests for milk progesterone to determine which cows are cycling normally.

When cows show a low level of progesterone at least once in 3-4 samples he knows they are cycling well and coming on heat.

But when all the samples are low he consults his vet – it could be that the cow is anoestrus. Alternatively, progesterone may be high due to a cystic corpus luteum – or because the cow is pregnant already.

Mr Black believes the early vet treatment is one of the main benefits of milk progesterone testing.

"Instead of waiting until 60 days after calving to call the vet to examine a cow, we know by day 40 whether she is cycling or not and can take action to get her back in-calf as soon as possible," he says.

Cows cycling normally are sampled for milk progesterone every other day from day 15 or 16 after a previous heat (or low level of progesterone during weekly sampling). When a new low level of progesterone is seen cows are observed closely at least three times a day for signs of heat. Those not seen bulling are served blind on the day after the low value.

Mr Black says that in such cases conception rates are about 10% lower at about 45% than the 55% achieved by service after observation. Heat detection rate at Wharton Farm is now 95%-98% compared with 65%-85% before use of progesterone testing.

Each test supplied by Ridgeway Science costs about 30p. For the 15 tests needed for weekly and daily sampling, the cost is £4 a cow.

&#8226 Dr Dick Esslemont of DAISY says that in the right hands, milk progesterone profiling reduces vet work on fit cows and delivers an extra £70-£100 profit a cow.