Our district vets are still diagnosing new cases of virulent footrot and with recent rain and lowering temperatures creating spread conditions, it is a timely reminder for all sheep producers to review their biosecurity practices and knowledge on the disease.
Spread conditions are environmental factors allowing the bacteria that causes virulent footrot (Dichelobacter Nodosus) to reactivate in dormant lesions and infect clean sheep.
These conditions occur when temperatures are mild, rainfall is high and pastures retain enough moisture to allow the skin between the toes of sheep to remain wet for long periods. Constantly wet skin loses its ability to repel bacteria and hence allows the footrot bacteria to establish and cause disease.
Footrot is introduced into a flock by purchasing infected sheep or having infected sheep stray onto a property, then mix with clean sheep during a spread period. The disease does not live in the ground or on mechanical vectors for longer than a week, but lives in pockets in infected hooves. These pockets can dry out over summer or during drought conditions only to reactivate when the above environmental conditions occur.
By following the below steps, you can reduce the chance of footrot becoming established in your flock.
Firstly, inspect sheep regularly and get lameness investigated. The sooner the disease is detected, the quicker management practices can be put in place to reduce spread and impact on a flock. Sheep can be lame for a number of reasons, so not all lameness is indicative of virulent footrot.
Next, ask for a National Sheep Health Declaration when purchasing sheep. This is a document where the seller outlines the presence of certain disease in the mob/s for sale including both benign and virulent footrot.
Next, inspect and quarantine purchased stock. All newly purchased sheep should be inspected on arrival and any concerns checked by a vet. As good practice, all recently introduced stock should be quarantined from existing stock for as long as practical following purchase, preferably through a spread period. This allows incubating disease in new stock to be diagnosed and managed. Quarantining sheep until after a spread period will allow dormant footrot to reactivate and ideally be detected before it has an opportunity to spread to other sheep.
Make sure you maintain boundary fences. This will help prevent straying sheep entering a property.
Do not forget to inspect straying sheep and goats for disease. If straying sheep are suspected of carrying the disease, sheep they have mixed with should be isolated in order to prevent spread of the disease to the remaining flock.
If you are concerned about lame sheep or would like to discuss footrot further, please give an LLS district veterinarian a call:
– From the Local Land Services Tablelands Telegraph – April 2021