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.

PAGs are detectable as early as 28 days after insemination, so it is recommended that the test can be used from this point and throughout the whole gestation period.

The Alertys Milk Pregnancy Test has been developed to perform robustly on milk samples from cows, goats, sheep and water buffalo. The test can be run on samples that have been exposed to heat treatment (during milk component analysis) and preserved milk samples (e.g. Bronopol). For more information on the types of preservatives that have been validated with this test, please contact your IDEXX technical services representative. The assay can be run on whole or skim milk samples. Samples should not be micro-waved prior to testing.

Yes, if certain conditions are met.

• Excellent results obtained on well-parameterised Lely* robot:

  • Ensure sampling shuttle is installed correctly horizontally (verify with a spirit level). Please also ensure that the length of hose is well adjusted.

  • Increase emptying time of the milk pump ≥ 9 seconds (do not forget to reset the parameters to the initial setting after the weighing).

• The results of reliability are very similar to the values obtained from a normal milking parlour (only 3.5% of samples to be re-checked and 2% false positives).

*Test in progress on other brands

Yes, frozen and thawed samples can be run on the Alertys Milk Pregnancy Test. Make sure to thoroughly mix the thawed sample. Mix by gentle vortexing or inverting at least five times. Frothing or overmixing of samples will cause denaturation of proteins. If a sample is frozen and thawed repeatedly, the sample quality may suffer due to clotting, and test results may be altered.

Yes, you can use all the milking parts. There is no difference in the results. The usual procedure is to discard a few streams of milk and then collect the milk into a tube.

Open cows can have a major impact on profitability. Research shows that the average cost per open cow is €5 a day*. These costs include the value of the milk the cow would have produced, the value of her calf, and other relevant factors. Dairy farms can optimise profitability by shortening the calving interval and reducing the number of days that cows are open.

*De Vries et al, Economics of improved reproductive performance in dairy cattle (Publication AN 156), Gainesville FL, University of Florida Institute of Food and Agriculture Science; 2005

PAGs are detectable as early as 28 days after insemination.

PAG levels take time to disappear after calving or embryonic loss. We recommend leaving 60 days after calving and up to 10 days after early embryonic loss before using the test. The further on in gestation then the longer it takes for the PAG level to drop below the cut off line.

Whatever the method of pregnancy diagnosis, it is useful to do a confirmatory test after around 70-110 days post breeding*. The earlier the initial pregnancy test, the more important the confirmatory test is.

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The value of doing an initial pregnancy test early is to quickly identify the open cows so they can be re-bred. Most open cows should have been detected in oestrus at the 3-week return point. However, some balance needs to be struck. If we test too soon, a greater proportion of pregnancies will be lost (a confirmatory test is definitely required) and if we test too late, we aren’t getting the advantage of finding those open cows to serve again.

*LeBlanc, S. J. 2013. Short communication: Field evaluation of a pregnancy confirmation test using milk samples in dairy cows. J. Dairy Sci. 96:2345-2348.

The test will provide a pregnant, non-pregnant or 're-check' result. It cannot tell the stage of gestation, the sex of the calf or if the cow is carrying multiple calves.

Poor quality samples may compromise the accuracy of test results. Bronopol or a similar preservative may be used to maintain sample quality. Prior to testing, milk samples should be checked to ensure that they are not soured or separated and are free from contamination. Care should be taken to minimise the likelihood of milk carry-over from cow to cow during sample collection, particularly when using samples collected for routine herd recording

There is some evidence to suggest that higher milk yields result in lower circulating PAG levels, but this does not affect test results. There is currently no evidence to suggest that other milk components have an effect on test results. Also, IDEXX has no evidence to date to suggest that antibiotic treated milk has a negative effect on the test results.

Early embryonic loss can occur in 10-20% of previously confirmed pregnancies. You can use the milk pregnancy test to confirm pregnancy (to detect early embryonic losses) and to prevent dry-off of open cows or slaughter of pregnant cows. There is no extra hassle and in many instances your milk laboratory can automate this testing for you. So, you are alerted if a cow needs attention and you can have the vet out to check. Many Milk Recording Organisations/Labs also offer milk pregnancy testing anytime and have a sample kit available for you to collect your own samples.

The test is proven to be as accurate as ultrasound and can be used as early as 28 days after insemination.

When it comes to the overall accuracy of the test, it has been compared to transrectal ultrasound and per-rectum palpation. A pregnancy test can be measured by its ability to find open cows or pregnant cows. These are called negative and positive predictive values.

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A Canadian study¹, comparing veterinary per-rectum palpation and the Alertys* Milk Pregnancy Test ≥ 60 days after service in 683 cows, found agreement in over 99% of results.

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In a large Australian study², pregnancy diagnosis using transrectal ultrasound and the Alertys Milk Pregnancy Test had similar good sensitivity - ultrasound 94% and Milk PAG test 96% - but differed in predictive values. Pregnancy diagnosis in seasonally calving herds around 85-100 days after the start of the breeding period using the milk PAG test resulted in a higher negative predictive value but lower positive predictive value than testing via ultrasound.

Also, a recently published Canadian paper³ was conducted to estimate the diagnostic accuracy of both the test and transrectal ultrasound by an experienced skilled operator among individual dairy cows at 28-45 days following the breeding. In fact, the results found that both tests have excellent accuracy for pregnancy diagnosis, with near-perfect sensitivity and specificity. There was very little disagreement observed between the two tests, with just 23 cows out of 519 pregnancy tests yielding discordant results.

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Overall, there is no disadvantage in using Alertys Milk Pregnancy Test for early pregnancy diagnosis when it comes to accuracy, compared with other traditional methods. The advantages would be simplicity, it being a non-invasive test, and it not being dependent on the availability of a highly skilled and experienced technician or vet for reliable early diagnosis.

Reference:

¹⁾ LeBlanc, S. J. 2013. Short communication: Field evaluation of a pregnancy confirmation test using milk samples in dairy cows. J. Dairy Sci. 96:2345-2348.

²⁾ Shephard, R. W., and J. M. Morton. 2018. Estimation of sensitivity and specificity of pregnancy diagnosis using transrectal ultrasonography and ELISA for pregnancy-associated glycoprotein in dairy cows using a Bayesian latent class model. NZ Vet J. 66(1):30-36.

³⁾ Dufour, S., J Durocher, J Dubuc, N Dendukuri, S Hassan, and S Buczinski. 2017. Bayesian estimation of sensitivity and specificity of a milk pregnancy-associated glycoprotein-based ELIDSA and of transrectal ultrasonographic exam for diagnosis of pregnancy at 28-45 days following breeding in dairy cows. Prev Vet Med 140:122-133.