Shropshire Farming Talk: Pregnancy Diagnosis in Dairy Herds
With conception rates regularly below 50%, it is important to recognise non-pregnant cows as early as possible and one method is to test through regular milk samples.
Milk pregnancy testing helps dairy farms shorten the calving interval and reduce the number of days that cows are open.
Open cows can have a major impact on profitability. Research has indicated that the average cost per open cow is £4.50 per day.
These costs include the value of the milk the cow would have produced, the value of her calf, and other relevant factors.
Therefore, if one cow stays open 20 days longer than expected, the farmer loses £90 on that single cow.
Considering a 100-cow dairy farm, this effect can have a tremendous impact and can reduce profitability by as much as £9,000.
The milk pregnancy test is non-invasive and hassle-free by testing samples from milk recording. The test detects highly specific markers of pregnancy: pregnancy-associated glycoproteins (PAGs). Unlike progesterone levels that fluctuate naturally during a cycle, PAGs are only produced in the presence of an embryo or foetus.
In the CIS laboratory at Telford, a few drops of milk are placed in each well, on ELISA plates.
Several reagents are added successively. An optical density reader is used to measure the colour of each milk sample and if the cow is pregnant, a colour develops; if she is not pregnant, the wells remain clear.
The milk pregnancy test is proven to be as accurate as ultrasound and can be used as early as 28 days after insemination. Already more than 27 million tests performed worldwide based on the ELISA technology.
There are three recommended test windows, the first early test is from 28 days post AI to identify non-pregnant cows as early as possible so the cow can be re-inseminated quickly.
The second at around 70-110 days to reconfirm and detect early embryonic death, and then the third window is before dry off to avoid drying off a non-pregnant cow in anticipation of calving.
From timely breeding to pregnancy confirmation to successful calving – milk pregnancy testing is key component on today’s dairy farms.
It can help you get herds below the national calving index of 420 days.
Amanda Wilkes, CIS Area Manager
