As farmers may be looking to assess their flock for the next breeding season once they are dried off after weaning, it is an important time to control the spread of diseases on-farm.
With prices reducing for sheep farmers at the factories in recent weeks, measures should be in place to maintain a healthy flock to ensure farmers will enter the breeding season with a full selection of rams and ewes to achieve lambing targets.
This can be achieved by farmers employing a good biosecurity programme, which must be implemented especially when farmers are buying in sheep, with this time of year being when new animals are being bought between marts and factories.
Disease in sheep
According to Eamonn Dempsey, a Teagasc advisor, once a farmer purchases and introduces sheep to the existing flock there is a risk of introducing disease, parasites or anthelmintic resistance.
These highly infectious diseases include footrot, Contagious Ovine Digital Dermatitis (CODD), and iceberg.
Diseases with incubation periods that will show symptoms after six months to two years include:
- Scrapie;
- Johne’s disease.
Sheep can also carry abortive agents, such as enzootic abortion, which can cause the carrier to look healthy but will eventually abort and will spread the disease throughout the flock.
Farmers must vaccinate sheep that they purchase in against enzootic abortion and put a vaccination programme in place for future purchases.
Purchased animals should be quarantined for four weeks and regularly checked for signs of lameness.
For treatment of internal parasites, Teagasc recommends sheep be treated with a Monepantel (group 4 – AD) and either Levamisole (Group 2 – LV) or Macrocyclic Lactone (Group 3 – ML).
The sheep should be housed for 48 hours after their dose, and then turned out to a pasture recently grazed by sheep.
Sheep bought into a farm should also be dipped for the control of scab, lice, keds and ticks, and be vaccinated with clostridial and pasteurella vaccine.
Sheep with suspected or confirmed notifiable diseases, such as sheep scab or scrapie, must be notified to the Department of Agriculture, Food and the Marine.
Purchasing animals
To reduce the risk of disease coming into sheep farms, farmers should aim to produce and keep their own replacements, thereby reducing the number of flocks they buy from.
Dempsey said: “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 must take responsibility for selling sheep that are healthy, disease free and be open and honest about the health status of their flock.”
Sheep that are being treated for diseases must not be sold until they are in full health, while the withdrawal periods on the veterinary products being administered to them must be obeyed.
A closed flock is also recommended by Teagasc as key to maintaining a good biosecurity programme, as the flock being kept within “effective boundary fences” will prevent contact with neighbouring animals that may have disease.