Mr Price-Davies has discovered the true extent of foot rot infection

Tag : Zinc Sulphate
Carmarthenshire farmer Iwan Price-Davies found that sheep will milk better and keep a good condition when they are bred with sound. The funded project was carried outon the 183ha (450-acre) upland farm in Carmarthenshire where MrPrice-Davies runs a flock of 1000 Beulah Speckled Face ewes. Byworking closely with his specialist sheep vet, Mr Price-Davies hasdiscovered the true extent of foot rot infection within his flock.
Consultant vet Kate Hovers visited <ahref="http://maps.google.co.uk/maps?f=q&hl=en&geocode=&q=babel&sll=51.856427,-4.310537&sspn=0.164549,0.218697&ie=UTF8&ll=52.011303,-3.713036&spn=0.010249,0.013669&t=h&z=16">GellyrhyddFarm</a> _fcksavedurl=""http://maps.google.co.uk/maps?f=q&hl=en&geocode=&q=babel&sll=51.856427,-4.310537&sspn=0.164549,0.218697&ie=UTF8&ll=52.011303,-3.713036&spn=0.010249,0.013669&t=h&z=16">GellyrhyddFarm</a>" _fcksavedurl=""http://maps.google.co.uk/maps?f=q&hl=en&geocode=&q=babel&sll=51.856427,-4.310537&sspn=0.164549,0.218697&ie=UTF8&ll=52.011303,-3.713036&spn=0.010249,0.013669&t=h&z=16">GellyrhyddFarm</a>" _fcksavedurl=""http://maps.google.co.uk/maps?f=q&hl=en&geocode=&q=babel&sll=51.856427,-4.310537&sspn=0.164549,0.218697&ie=UTF8&ll=52.011303,-3.713036&spn=0.010249,0.013669&t=h&z=16">GellyrhyddFarm</a>" three times over a 12-month period to assesslameness levels and monitor the effectiveness of a lamenessprevention programme.
The flock regularly had one or two lame sheep, but it was quite arevelation when closer inspection showed that 17.5% needed someform of foot rot treatment.
It can be difficult to assess the true extent of lameness in alarge flock, explains Ms Hovers. "However, by inspecting each sheepindividually in a turnover crate, we found foot rot was present inmore than twice as many sheep as those that were showing obviousphysical signs of lameness."
With so many sheep showing signs of foot rot infection, theproject's next phase was to introduce a whole-flock controlprogramme to contain the disease.
All the sheep were injected with an initial dose of foot rotvaccine, to allow each animal to build up immunity to the <ahref="http://en.wikipedia.org/wiki/Dichelobacter-nodosus">Dichelobacternodosus</a> bacterium that causes foot rot, and to stopinfection spreading more widely. Sheep were also walked through azinc sulphate footbath, the lame sheep going through last toprevent any sound animals becoming infected. Lame sheep were thengiven an injection of long-lasting oxytetracycline antibiotic.
split flock
The flock was then split into two groups - those sheep that weresound were turned out onto clean pasture that hadn't been grazedfor a minimum of two weeks, while lame sheep were isolated andre-treated with antibiotics a week later if still lame.
Sheep were then inspected again a month later. Any sheep still lamereceived another antibiotic injection, as well as a booster of footrot vaccine. Out of the 638 animals inspected, 363 were sound, butneeded some foot-trimming, while 112 needed treatment for foot rot.
Over the next 12 months, sheep were constantly monitored. Thisresulted in 19 ewes culled due to recurring or unresponsivelameness. The whole flock was also given a foot rot vaccine boosterinjection before tupping, and put through a formalin footbath threetimes during the year.
reduced lameness
One final inspection at the end of the 12 months indicated the newregime had drastically reduced the incidence of lameness. Out of635 sheep, only 27 showed obvious signs of lameness, and this wasthe first time that no animals needed foot care beforeover-wintering.
Mr Price-Davies remarked that: "We haven't got rid of foot rotcompletely, but we have reduced the number of infected sheep to amuch more manageable level.
"By being more proactive, we have saved ourselves a lot of time andadditional work, as there is a lot less foot-trimming to do. Wehave also noticed a vast difference in the performance of oursheep. At the end of the day, if the sheep aren't lame, they willdo much better in terms of milk production, growth rates andoverall body condition."
Where foot rot is the definite cause of lameness, vaccination canbe a highly effective way of controlling the disease, says MsHovers. "But, for vaccination to be effective, producers must havea definitive diagnosis of foot rot, as opposed to other lamenessconditions such as scald or <ahref="http://www.moredun.org.uk/feature-article.asp?ref=25">ContagiousOvine Digital Dermatitis</a> (CODD)" she said.
"Sheep do not produce a natural antibody response to the bacteriumthat causes foot rot. The only way to break the disease cycle is toundertake a whole-flock vaccination programme.
"This simplifies treatment, reduces the disease challenge foruninfected sheep and helps identify animals not responding totreatment for culling," she adds.