'Sheep purchases bring risk of introducing disease or parasites to farm'

Photo Brian Farrell
Photo Brian Farrell

Eamon Dempsey

Over the summer/autumn there is a lot of movement of sheep on farms, be it either drafting lambs for sale to factories/marts or, with breeding sales, the movement of breeding stock from farm to farm.

For farmers who do not keep a closed flock, they should be aware of the key risk from a health point of view of bringing in new animals onto the farm. Once a farmer purchases and introduces sheep to the existing flock there is a risk of the introduction of a disease or parasite which is not currently in the flock.

Farmers involved in the knowledge transfer programme are required as part of the scheme to complete a flock health plan with their VET.

This plan sets out a health programme for managing sheep over the year at weaning, mid-pregnancy and pre and post lambing, bringing health issues and parasites to farmers' attention and allowing them to be proactive rather than reactive in parasite and disease control. All farmers should have a flock health plan which provides advice for the introduction of stock onto the farm.

Diseases such as footrot and Contagious Ovine Digital Dermatitis (CODD) are highly infectious and can spread rapidly in your flock.

Purchased sheep can also carry resistant parasites, which are resistant to dosing products e.g. stomach worms. The big concern for farmers is the introduction of abortive agents e.g. Enzootic Abortion.

The sheep carrying this infective agent can look perfectly healthy but will abort at a later date and spread this disease to other sheep in your flock.

It is advisable for farmers to vaccinate purchased sheep against enzootic abortion and have an enzootic abortion vaccination programme for the entire flock.

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Some diseases have long incubation periods and symptoms will not appear until 6 months or 2 years later e.g. Scrapie, or Johnes Disease. We know the risks of the introduction of infective diseases, so how do we minimise the risk. For lameness and anthelmintic resistance issues, farmers must quarantine all purchased animals for a period of around 4 weeks where possible. Purchased Sheep should be treated with Zolvix or injectable Ivermectin and left in the shed or pen for 48 hours to allow infected faeces to pass out in the yard rather than onto fresh pastures.

It is a good idea to purchase from a known source, where you can talk to the farmer and ask questions about the health status of their flock. Ideally, farmers should aim to keep their own replacements and reduce the number of flocks they buy from.

Rams go through a rigourous selection process checking teeth, feet, Eurostar index etc, so they should be fit and healthy upon introduction to the flock, but quarantine and further observation is advisable.

Farmers know all too well the costs and hardship associated with diseases and parasites on their farms. Every farmer involved in buying and selling sheep must take responsibility for selling sheep that are healthy, disease free and be open and honest about their flocks health. Sheep which are treated should not be sold until back to full health, and always obey the withdrawl periods on treatment products.

Diseases such as Sheep Scab, Scrapie or other notifiable diseases, if suspected or confirmed, must be notified to the Department of Agriculture, Food and the Marine in accordance with the Regulations. If you buy in a condition like CODD or enzootic abortion it has a significant effect on the production potential of your flock, not to mention labour and medical expense.

All farmers purchasing sheep must have a good biosecurity programme which is aimed at minimising the risk of buying in a disease and operate a closed flock if possible.

Online Editors


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