There is no doubt that milk pregnancy testing has grown in popularity on dairy farms across the country over the last couple of years, but is it as accurate as scanning?
Milk pregnancy testing works by detecting the protein changes in the milk that are associated with pregnancy.
Milk pregnancy testing gives farmers the opportunity to check for pregnancy from a milk sample that has been taken at your routine milk recording or through individual post sampling.
The benefits of milk pregnancy testing is that you are not adding unnecessary stress to the cows and it is non-invasive, so there is no risk to the vulnerable growing fetus.
However, scanning, when it is done in a calm and measured manner without upsetting the cows, can be just as effective.
For both scanning and milk pregnancy testing, it should be at least 28 to 30 days since the last cow in the herd could have been served for the cow to be tested or scanned. This is done to ensure accuracy, as it is difficult to pick up very early pregnancies.
No matter which option you choose, some form of pregnancy testing should be carried out, as each day that a cow is empty can cost you between €3.70-€6.10, which could have a serious impact on farm profitability.
Milk pregnancy testing
The proteins that the test is checking for are pregnancy associate glycoproteins (PAGs), which are specific to pregnancy in cattle.
The use of milk pregnancy testing can be done to compliment your scanning results to ensure complete accuracy, but it can also completely replace the need for scanning on your farm.
The test has three varieties, depending on the expected pregnancy of the cow: Early test; confirmation test; and pre-dry off test.
The early test is used from 28 days after artificial insemination (AI) to identify non-pregnant cows as early as possible, so the cow can be re-inseminated quickly.
Meanwhile, the confirmation test, used from 70 to 110 days, is utilised to detect embryonic death.
Finally, the pre dry off test can be used in late gestation to avoid drying off a non-pregnant cow in anticipation of calving.
The accuracy of the milk pregnancy test from day 28 post-AI is estimated to be 98.7% which seems to be on par with palpation and ultrasounds.
Milk pregnancy testing does not include the stress and labour of scanning, as a lot of the time scanning can be a stressful day on both the farmer and the animal.
Scanning
Scanners will be able to give you a good estimate of the number of weeks that each cow has gone in calf and you can use this information to predict the cows due date which will influence how she is fed.
Delaying scanning until later when some cows have gone 12 weeks or more in calf can lead to issues identifying the exact stage of pregnancy or if the cow is carrying twins or not.
By identifying when cows are due to calf, they can be grouped accordingly nearer their calving time to allow for an easy calving with minimum moving around.
Scanning certainly has that advantage over milk pregnancy testing that it can predict when your cow is going to calve, making it easier to make management decisions around diet and facilities.
Scanning costs can vary but generally cost around €5/cow plus a call out charge of €20 to €50, according to Teagasc.
Rates will vary depending on the number of animals being scanned and the time it takes to scan the herd of cows but it is money well spent.
Milk pregnancy testing costs around €4/cow for each test and again, is money well spent to know which cows are empty and in calf.
The two pregnancy tests have their pros and cons and it is not uncommon to for farmers to have both carried out on their farms.
This is done firstly to identify what is in calf through the milk pregnancy testing and then to follow up with a prediction on when she is due to calve down through scanning.