Bacteriological testing uncovers some “unusual suspects”

Wet weather and a bit of increased stress on cows has led to an increase in the number of cases of mastitis recently. This has led to an increase in the number of milk samples we have been looking at over the same period. Usually, the bacteriological cause of mastitis at this time of year is one of the “usual suspects” ie. Staphylococci or Streptococci. In most cases the cow has picked up one of these “bugs” at milking time, ie. these types of mastitis are generally contagious, meaning they spread from cow to cow, usually on the milking operators’ hands at milking or through the milking machine. Recently however when milk samples have been cultured and analysed in the lab, we have seen some cases of bacteria which are not the “usual suspects”

One such case was a mastitis sample which contained a pure growth of a particularly nasty bug called Pseudomonas aeruginosa . Usually this organism is present in the environment and is not the main cause of mastitis on farms, however in some cases it can cause mastitis in its own right. In these cases, the bacteria can gain entry to the udder from the housing, but also through the use of contaminated water in the milking routine. I call this a particularly nasty bug because when it was tested to see which antibiotic tubes were effective against it, we found that it was resistant to all except one of the routinely used antibiotics.

Another interesting cause of bacteria recently was a yeast called Candida albicans. Again, yeasts are not a major cause of mastitis, but sometimes occur after a cow has been treated on several occasions with intramammary antibiotics. The reason being that yeasts are not killed by antibiotics (as was the case with this one when we tested it in the lab). Recently we have become more aware that there is a natural biome of “good” bacteria in the teat canal which helps defend the udder from infection. Over-use of antibiotics may interfere with these defence mechanisms, and allow the overgrowth of yeasts.

Bacteriological culture of mastitis samples is the only way to identify these “unusual suspects”, and treating these sorts of cases without knowing what’s going on can make matters worse. The lead up to drying off is a good time to discuss with your vet about some monitoring of high cell count cows, or problem cows to build up a profile of the bugs present on the farm.

The vet can then use this information to help inform the decision on which are the correct dry cow treatments to use on the farm. There is a growing move towards selective dry cow therapy, where some of the cows on the farm are infused with antibiotics at drying off if needed, while others are left untreated. Carrying out selective dry cow therapy on a farm without knowing the causes of clinical or subclinical mastitis can be very dangerous, as you can get a big flare up in the incidence of mastitis on the farm in the following season, particularly if there are highly infectious organisms such as Staphyloccus aureus present on the farm.

New Submission form

We have added a new style of submission form for use by our veterinary clients. We hope that the new form will be easier to use, and has a full list of all of the tests which are available from FarmLab Diagnostics, including our new range of equine tests.  The form also contains information on the various tests which we offer, which means that in total it is 7 pages long. We only require that the first two pages, which can be printed front on back on one sheet will be used for sending with samples. We advise vets to read the information provided on the other sheets to avoid confusion in relation to test submission, and limitations of certain tests. The form is available for download from our downloads page or can be accessed directly by clicking on the following link: Should vet practices have any queries please feel to contact us to discuss. F#514-1 Diagnostics Sample Submission Form.docx

Early Lambing – Investigating abortions in sheep

Early lambing is less popular than it was in our part of the world, but we have had some cases of sheep aborting in recent weeks. This mainly has been in pedigree lambing flocks where early lambing is still popular. One recent case involved a hogget delivering two malformed lambs which were premature and partially decomposed. Continue reading “Early Lambing – Investigating abortions in sheep”

Elisa testing – Enzyme Linked Immunosorbent Assay Tests

Elisa testing stands for Enzyme-Linked Immunosorbent Assay. It is a test method often used to detect antibodies to an infectious or parasitic disease. Antibodies are immunological proteins produced by an animal in response to exposure to infection. Continue reading “Elisa testing – Enzyme Linked Immunosorbent Assay Tests”

Investigate the Reason for Chlamydia Abortus / Sheep Abortion

Please download a story in the Irish Farmers Journal where a Sligo vet discusses the causes of infectious abortion in sheep. The most common causes include Toxoplasmosis and Chlamydia. Both can be detected by a test provided by Farmlab and you can order the sampling kit here.

Continue reading “Investigate the Reason for Chlamydia Abortus / Sheep Abortion”

Testing for Infectious Bovine Rhinotracheitis (IBR)


Infectious Bovine Rhinotracheitis (IBR) is caused by bovine herpesvirus 1 (BoHV-1). This virus causes an acute upper respiratory tract disease which can lead to fatal pneumonia. Infection can also cause a severe and prolonged drop in milk yield, reduced fertility and abortion. Continue reading “Testing for Infectious Bovine Rhinotracheitis (IBR)”

What is Bovine Viral Diarrhoea (BVD) in Cattle?

BVD in Cattle

BVD is a viral disease of cattle, caused by a pestivirus, called Bovine Viral Diarrhoea Virus (BVDV). BVDV can infect cattle at any stage of their lives, resulting in impaired immunity thereby weakening the immune system and leaving the animal susceptible to other infections at the same time. This can be particularly pronounced in the case of cattle which become concomitantly infected with other respiratory viruses, such as IBR. Combined infection with IBR and BVD can cause a severe fulminating pneumonia and potentially death. Continue reading “What is Bovine Viral Diarrhoea (BVD) in Cattle?”

Veterinary sample submission form

We have updated our sample submission form for veterinary practitioners to include all the new tests which we have added recently. We have also included some explanatory notes relating to the various tests . We would ask veterinary practitioners to use this sample submission form when submitting samples. Continue reading “Veterinary sample submission form”

Submission Form

We have added an updated submission form on our downloads page. There is also now a Word version of the submission form for anyone who would like to fill it in electronically. We have added an option to indicate whether sample results should be transferred to ICBF or not. This is particularly significant for Johnes disease tests. Continue reading “Submission Form”

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