A vaccine is now registered for use across Australia that will assist producers to eradicate virulent footrot from their sheep flocks. This provides an alternative to the use of antibiotics in limiting the number of sheep to be culled during the summer program of eradication by repeated inspections, which is necessary to get rid of this nasty scourge. At the June 2017 BESTWOOL/BESTLAMB conference in Bendigo, Dr Bruce Jackson from Tasmania described how to apply this new technology. This was based on his experience using experimental vaccines that the commercial vaccine is based on. This is a summary of his advice. The previously available commercial vaccine contained 10 serogroups of the bacterium Dichelobacter nodosus. However, with this many serogroups present, the vaccine was, at best, only able to control the disease.
By limiting the number of serogroups in the new vaccine to only one or two (customised for the sheep on your farm), a stronger and longer-lasting immunity is developed in vaccinated sheep. This means up to 95% of infected sheep can be completely cured.
An outbreak of footrot can result in an average weight loss of 50g/day resulting mainly from pain and reduced feed intake. It can have a direct effect on fertility of rams with a subsequent lower lambing percentage (>10%). Furthermore disease is associated with significant treatment costs and the condition can predispose to other diseases such as:
–Twin lamb disease
Including culling, the total cost of a lameness case can result in a loss of between €6.50 – €7.80/ewe.
The most common cause of lameness is foot-rot, which is an extremely painful, production-limiting disease that affects sheep of all ages. oot-rot is caused by the naturally occurring bacteria Dichelobacter nodosus, which is carried by healthy as well as lame sheep, and can remain infectious up to 14 days on contaminated pasture. This means the feet of infected sheep play a significant role in the transmission of the disease. By implementing each of the five points of the five-point plan, the incidence of sheep lameness can be reduced below 2% by the end of the third year of implementation.
Features of Foot Rot Vaccine For Sheep
The important thing about vaccination is fitting it into the farming calendar. The timings you need to consider include:
- Make sure you leave six weeks between the first dose and the booster.
- Make sure no other vaccines are used within two weeks of vaccination, to allow the immune system to fully respond to one vaccine before using another.
- When vaccinating close to tupping or lambing, make sure you vaccinate at least six weeks before tupping, four weeks before lambing or four weeks after lambing, to prevent the immune response affecting fertility and to avoid stress at these critical times.
- Don’t vaccinate six to eight weeks before shearing, and within the previous six months of animals being shown or sold, as a well-
defined, inactive lump at the site of injection may occur.
Most people will vaccinate before the risk period on their farm, and that time will obviously differ between farms. For some, foot-rot may be more of a spring/summer issue after lambing, but for others it could be in the autumn or when animals are housed. Timing should be four weeks before the risk period. You need to work with your healthcare provider to see when the problem is, and then plan in the vaccination, tailored to meet the individual flock.
Control of Foot Rot in Sheep
Control of footrot can be summarised by the acronym RSTUV:
- Remove chronically affected sheep. Reduction of circulating bacteria can be achieved by progressive culling of those animals that are identified as a potential source of the bacteria.
- Segregation – All sheep entering the flock must be quarantined for at least 2 weeks before allowing access to the main flock. Maintaining a closed flock is the best approach. All clinical cases should be hospitalised (segregated) from cohorts as this reduces spread of infectious organisms.
- Treat clinical cases – All clinical cases of footrot require aggressive treatment with topical and systemic antibiotics. Footbathing may also be useful. Further information is available from your local veterinary practitioner from whom advice should be sought.
- Understand farm specific factors – Issues such as roadway surfaces, bedding and other under-foot conditions that could contribute to elevated lameness should be addressed.
- Vaccination – The use of vaccine helps to elevate immunity and reduce bacterial circulation. The vaccine is licensed as an aid in the reduction of footrot. It is also licensed for the treatment of footrot in Northern Ireland. This product may only be prescribed by your veterinary practitioner from whom advice must be sought. Further information, relevant to your region, may be obtained on the product by browsing under the heading Species / Relevant Region / Sheep on the homepage.
Prices of Foot Rot Vaccine For Sheep
$35.00 – $35.98