Milk Pregnancy Test

A simple milk test providing accurate and timely results

Meet Patrick Stevens

Routine PD scanning is being replaced by Alertys™ Milk Pregnancy Test from IDEXX, also known as the Pregnancy Associated Glycoprotein (PAG) milk test, a simple method providing accurate, timely results for a growing number of dairy farmers. Amongst them is Patrick Stevens who is both expanding his Devon-based herd and moving from all year round to autumn block calving.


'Introducing PAG 70 days after service has brought ‘peace of mind’, says Patrick Stevens who currently manages a 240-cow herd at Upottery, near Honiton. 

It’s a simple milk pregnancy checker that is delivering information to build up a picture and mathematical probability and it is helping us to respond more promptly to herd status. Every open day costs £3 a head, so the sooner the better we know when a cow is in calf

“We’ve just started serving early November through to the end of January and we are gradually tightening up the calving pattern. PAG has helped identify which cows remain open and need to be served again. Since we introduced the test in 2017 to routinely check the herd once a year, 60% are calving in the first six weeks, that’s a 10% improvement. By 2021 I want to move that figure to 80%, and eventually 100% within the first three cycles,” he explains. 


“To improve accuracy and ensure we’re on target, then we plan to PAG milk test after the first 30-day service period, consequently it will eliminate that current 40-day window of uncertainty amongst those cows which conceived in the first cycle.”


Patrick says the logistics are simple. After signing up for PAG with CIS, it delivers the milk sample pots to the farm, collects within 72 hours, and issues for lab analysis. I receive notification from CIS when the results are ready and I log in to check them. 

We currently have so many changes going on in the herd, this new service is relatively very straight forward. We are running a profit-based business. My objective is to focus on one job and to do it well which has led to us changing our strategy

Patrick Stevens 1

“We are in the process of swapping a sheep enterprise for total dairy enabling the herd to expand from 240 to 400 cows and we are just about to start building a new dairy. For the last five years, we’ve been moving from all year round calving to a low-cost autumn block calving herd - mainly Jerseys with some crossbreds, and it is currently averaging 5,000 litres, 5.1% BF and 3.7% protein, a yield level we are planning to increase by 30% along with the constituent value."

“We’re farming 600 grassland acres at 800’ on medium to heavy clay; March and April can be pretty harsh up here and it would be a struggle to get sufficient grazing days for a spring block calving herd. 


We used to PD the entire herd just once a year after the service period was complete, however, we were getting nervous about upsetting a pregnancy whilst it is still fragile in the early stages of pregnancy. The PD scan process was a hassle, it demanded extra time and labour and we have poor handling facilities. It was getting stressful not knowing when a cow was in calf until we had officially finished serving."


He adds: " Whilst PAG is marginally more expensive than PD scanning, the milk test has overcome all those PD induced issues and it seems to particularly lend itself to block calving herds. The procedure is unobtrusive, it is theoretically accurate and what’s more it’s given me that peace of mind.” 

PAG is another tool in the box, it offers another indicator that helps to build up the whole herd picture of what can be done differently. It also provides an opportunity to bring about another incremental change. I think it’s easy to overlook a 1%, 2% or 3% improvement, however its these small changes over a period of time can make a real difference to any herd and to any business

PAG Pregnancy Checker

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The simple Milk Pregnancy Test measures Pregnancy Associated Glycoproteins (PAGs)

PAGs are produced by the placenta once pregnancy is established

Milk samples can be tested from 28 days post-insemination to find non-pregnant cows, and throughout gestation to confirm pregnancy status

Up to 24% of cows can lose a pregnancy from 28 days after breeding 

Reliable pregnancy confirmation, 98% accuracy

Available from CIS, NMR and QMMS

What other customers are saying

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Reliable, Simple and Trusted

Developed by IDEXX, a world leader in veterinary diagnostics, the Alertys™ Pregnancy Tests have been performed more than 44 million times since 2010. Milk testing is trusted by tens of thousands of farmers around the world.
For more information on the Alertys™ Milk Pregnancy Test, please contact your milk recording organisations or visit our website:

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IDEXX Alertys Milk Pregnancy Test