Purchasing livestock is the most likely way of introducing disease into a herd, but that risk can be removed. Andrew Cobner president of the British Cattle Veterinary Association outlines disease avoidance strategies.
A plan drawn up in collaboration with the farm vet is key and should include knowing the health status of your own herd first.
You can then decide what health status you aspire to. Establish the health status of any herd you buy from.
See also: Neospora added to health scheme list
What is the single most important measure a farmer can take to avoid importing diseases?
Some diseases such as Johne’s are difficult to test for, so you need to know the herd situation. Ask whether your vet can make contact with the vendor’s vet; if they aren’t open to this, alarm bells should ring.
A single animal can damage the health of your herd, for instance introducing one Persistently Infected BVD carrier.
What quarantine procedures should be in place?
No direct contact should take place between purchased animals and their by-products – such as faeces, urine and milk – and the existing herd. The gold standard is a separate building or a field with a 3m separation fence around the perimeter.
Some advice suggests housing animals in the same building as existing animals will suffice with a 3m gap between both groups, but I wouldn’t recommend this because the animals share the same airspace.
Consider where dung and urine is draining to, because these can transmit diseases; for instance, the animals may be in a separate shed, but if their by-products are draining through the yard where your existing stock is, these animals are at risk.
How long should animals be kept in quarantine before they are introduced to other stock?
That time period will depend on the disease. For instance, bovine TB should be tested for 60 days after the animal’s arrival, so the quarantine period for TB is at least 60 days.
For IBR, the animal could be released into the herd a month after purchase if its test result is negative. The advice on quarantine periods is therefore not straightforward and veterinary advice should be sought.
What diseases should your vet screen for?
Bovine TB, BVD and Johne’s will already be on the radar because of national campaigns. Others to screen for will depend on an individual farm’s situation, but will include IBR, leptospirosis, campylobacter foetus venerealis, neospora caninum and salmonellosis.
But there are other diseases to look out for, such as digital dermatitis and infectious mastitis, because these can cause huge damage if not already present on the farm.
What treatments should animals be given on arrival? You are not only protecting your herd from the purchased animal, but that animal from diseases already present in the herd.
So during the quarantine period vaccinate against diseases you know you have. You may want to treat for worms and fluke if that is part of your protocol.
What are the common pitfalls farmers make when it comes to quarantine and treatment?
Another common mistake is applying stringent rules when buying a cow or bull, but forgetting this when it comes to what I would term as a casual acquisition, such as buying a replacement calf for a cow that has lost hers.
That acquisition can pose a significant risk because that calf may be a BVD carrier. The risk from by-products can also be forgotten, so consider drainage and avoid feeding milk from a bought-in cow to calves already on the farm.
How can dairy animals be managed separately through the parlour?
Very few dairy farms have a separate milking facility, so the best you can aspire to is to milk those animals after everything else, return them to the separate building or field and clean the parlour as usual.
Checklist for minimising infection risk
- Know your disease status
- Decide on your goals
- Formulate a plan with your vet
- Source from a single herd where possible
- Know the status of herds you are buying from
- Quarantine on arrival
- Test according to your health plan
- Vaccinate and treat in accordance with your status and plan
- Don’t forget biosecurity of the casual acquisition