PROG TEST CAN BE FEW AND FAR BETWEEN
PROG TEST CAN BE FEW AND FAR BETWEEN
STRATEGIC monitoring of dairy cow milk progesterone levels using as few as two samples could help improve fertility results.
Ed Darwash of Nottingham Universitys Cattle Fertility Research Group, has studied the use of a minimum number of progesterone tests taken on specific dates to improve fertility.
Testing milk samples every other day is expensive, with each milk sample costing about £3 to test in the lab. But fewer tests at specific times can give valuable fertility information more cheaply, especially with the £60-£100 cost for each cycle that a cow does not get in calf.
To check AI timing is correct just two milk progesterone samples taken five days apart are needed, says Dr Darwash.
"One test on the service day and a second five days after insemination will save having to wait until 24 days after service for a milk progesterone pregnancy test or until the cow is seen bulling. This allows the cow to be observed more closely when her next heat is due."
Dr Darwashs studies show that 11% of animals have high progesterone levels on the days of insemination, indicating late insemination. And five days after service 19.5% of animals show low progesterone and 12.8% high progesterone indicating inappropriate timing of insemination for ovulation, delayed ovulation or an incompetent corpus luteum.
He also suggests that just three milk samples taken in the week after a cow is treated by the vet would show if treatment had initiated normal heat and ovulation, or whether the cow needed re-treating, without having to wait another month.
For herds that suffer silent bullers, monitoring cows milk progesterone levels with eight samples over a 20-day heat cycle would confirm whether cows are cycling and ovulating normally. Typically these samples should be taken between 30-55 days after calving for insemination at 50 to 60 days.
Dr Darwash that says in his study 15.4% of animals showed delayed ovulation when tested on this protocol, regardless of previous ovulation, and needed treatment. This also identified irregular oestrus behaviour caused by follicular cysts in 2.2% of cows needing GnRH treatment.
"Milk progesterone testing saved waiting for 90 days after calving before treating cows for sub fertility."
Milk progesterone testing can also show if animals are cycling normally but do not visibly show heat, as may be seen in three out of every 27 heat cycles. This needs 18 to 27 tests between 20 and 55 days after calving for the vet to give the right treatment or to allow insemination using progesterone levels when there is a chance of conception.n
Ed Darwash… strategic monitoring of milk progesterone levels can help improve fertility.