Tips to avoid disease when importing dairy stock

Greater distance, reduced ability to inspect stock, and potential for infections means careful consideration and a robust approach is crucial when buying in stock from abroad, writes Paddy Gordon, Shepton Vets.

Risks when buying from abroad

Psoroptic mange

Purchase of cattle from Belgium has resulted in a form of mange (psoroptic mange – similar to sheep scab) occurring on a small number of farms in the UK.

This has the potential to become the most common skin disease in cattle with associated severe production losses and welfare concerns, according to the Animal Health and Veterinary Laboratories Agency.

This form of mange can become dormant, so infected cattle cannot always be identified.

It is also difficult to treat, with repeated treatments necessary to eradicate.

While primarily seen in beef cattle, there is no reason why psoroptic mange could not spread to dairy heifers.

The major concern here is once they are milking, the treatment options are restricted or involve prolonged milk discard.

Fatty liver

The import of in-calf dairy heifers from Holland resulted in a number of heifers suffering severe fatty liver and some deaths from liver failure.

This was noted by a number of XL Vets practices, including Shepton Vets. The precise reason for liver failure was not identified, but frequent movements, group changes and feed changes in late pregnancy were thought to result in repeated disruption to feed intake.

Due to the calf continuing to draw its energy needs from the heifer, these small upsets resulted in a more serious condition similar to pregnancy toxaemia in sheep.

Under the Welfare of Animals Transport Order (WATO) 2006, it is illegal to move cattle in the last four weeks of gestation.

Experience with heifers suffering liver failure indicates that not only is it illegal, but additional care must be taken with animals in late pregnancy to minimise upset and ensure good feed-quality and access.

BVD

Not all diseases are exotic. Bovine viral diarrhoea (BVD) is a widespread virus estimated to cost the UK industry £40m annually.

One of the most likely means of introducing BVD into the herd is through the purchase of a pregnant heifer.

Even when the herd is vaccinated there is no guarantee this heifer was either vaccinated, or responded to vaccination, prior to service. BVD infection during pregnancy can result in infection of the calf in the womb.

When the calf is born, it is persistently infected (PI) with BVD and will shed large amounts of BVD throughout its life.

There is no method available to test the status of the calf in utero and so buying pregnant animals carries a very high risk. Options available are to buy only from an accredited BVD-free herd, or to avoid buying pregnant animals.

Key actions

• Before acquiring animals from abroad speak to your vet and discuss the diseases you need to be aware of. Consideration of the health status of your herd and the vendor’s herd should be made. A good document to use as a guide is the Cattle Purchasing Checklist available on the DairyCo website – www.dairyco.org.uk
• Identify the required individual animal tests prior to purchase. Remember tests for Johne’s disease will not be wholly reliable as cows may not become positive until later in life. Herd status may be of greater use, as is the case for BVD status, when dairy heifers are pregnant. Check the due date of pregnant heifers to avoid contravening WATO.
• Establish if the animals are coming from a single herd or from a collection centre. If you do proceed, look closely at the distance involved and time for the journey. We have seen animals in poor health following prolonged or disrupted journeys.
• Talk to your vet about policy on arrival. Ideally a quarantine policy should be implemented, but this can prove impractical with milking animals. As a minimum there should be a plan for routine vaccination, foot-bathing and parasite control.

Considerations when importing heifers

• Discuss purchase with your vet
• New diseases can emerge from imported cattle, such as psoroptic mange
• Pregnant heifers can bring in bovine viral diarrhoea
• Transport of late-pregnancy heifers is illegal and may result in deaths from liver failure
• Disease status of both herd and individuals must be considered
• Consider distance to be travelled
• Consider authenticity and confidence of disease status information