lameness in sheep Flashcards
What us the impact of lameness in sheep?
- treatment costs
- Control costs
- wealfare
- Reduced growth rates
- lower conception rates
What are the clincial signs of Scald/strip/interdigital dermatitis?
- Inflammation of skin between claws
- Reddening
- Paste
- White / grey scum
What are the clinical signs of footrot?
- Smell
- Grey ooze
- Under running of hoof horn near to skin between claws
- Under-running of horn anywhere
What is the thought process behind the development of footrot or scold?
- Footrot is the commonest cause of lamenesswith Dichelobacter nodosus present on 97% of farms
- It used to be thought that Interdigital dermatitis (ID) (scald) was caused by Fusobacterium necrophorum and then Dichelobacter involvement led to Footrot ..but evidence suggests this is not the case!
now belived that both of these are present in all sheep and that load changes throughout the diesease process
What are the control measures of interdigital dermatis and foot rot?
- targeted at sheep with ID as well as FR
- Treat and separate from flock to prevent environmental accumulation of D. nodosus and further sheep-sheep transmission
What are the clinical signs of contagious ovine digital dermatits?
- Highly invasive and painful starting with a lesion at coronary band.
- Rapid invasion and underrunning of hoof wall.
- May be no involvement of interdigital space.
- Often >30% of flock in first year & then settles to ~2% lame sheep
- Many control approaches the same as for footrot
Sudden high level of lameness in a flock
What is the cause of contagious ovine digital dermatits?
What is the treatment?
Spirochaetes/treponemes involved but often mixed infection with D nodosus
Need long acting acting injectable antibiotic - amoxicillin or oxytetracycline and NSAIDs
Treat the individual sheep (not whole flock)
what factors are linked to lover CODD levels?
Is footbathing helpful?
What about foot trimming?
- Not purchasing sheep
- Isolating sheep returning to the farm
- Avoiding use of summer grazing away from farm
- Preventing ewes from mixing with neighbouring flocks.
- Examining feet prior to purchase.
- Use of footvax (?)
Quarantine important – introduction linked to poor biosecurity - Foot bathing didn’t provide as good control as parenteral antibiotics of individual sheep
- Foot trimming the flock more than twice a year associated with higher levels of CODD
What is a toe granuloma in sheep?
What is the treatment?
Inflamed granulomatous tissue coming out from under horn
From snipping into sensitive part of toe or chronic unresolved footrot
Very difficult to treat
* Don’t cut it off without a tourniquet or it will bleed profusely.
* Use local anaesthetic
- Can cauterise the granuloma site with a hot iron (nb keep clean!) & pack with copper sulphate crystals.
What is white line disease in sheep?
Defect on abaxial solar surface of horn at junction of wall and sole.
Two distinct presentations:
**1. Shelly hoof **
* Soil or debris accumulates laterally at white line.
* Seen as black half-moon if pared away.
* Often causes no lameness.
* However may lead to acute lameness if pus forms and damage and inflammation affects deeper laminae.
2. foot abcess
* Usual presentation is that of sudden onset extreme lameness with pain & heat but no obvious swelling.
* Pus tracks up & breaks out at coronary band.
* Small localised black spot seen at white line if foot is carefully pared.
* If possible avoid parenteral antibiotics until the pus has burst out – poultice the foot to encourage this.
* Do not pare the acute case.
What are foot abscesses in sheep?
What are these normally caused by?
What are the clincical signs?
What is the treatment?
- Deep sepsis of the distal inter-phalangeal joint.
- Often a sequel to trauma or infection or even following excessively strong foot-bathing
- Usually extreme pain, swelling, heat and discharging sinus at the coronary band or interdigital space.
- Usual course of action is to surgically amputate the digit though if caught early enough there may be success with antibiotic flushing.
What are the thoughts about trimming lame sheep feet?
lameness recovery levels were higher in animals that thad injectable and spray antibiotics and recovery was worse when trimming was performed
What is the hypothesis behind timming horn of sheep with foot rot?
Trimming horn delays healing
* Hypothesis: foot is inflamed and swollen and trimming removes sensitive tissue that would mend – longer time to recovery
Without antibiotics
* Does not clear D. nodosus and so further footrot occurs
* Damages foot and leads to further disease
What are the thoughts about trimming the feet of not lame sheep with over grown feet?
Routine foot trimming appears neither beneficial nor detrimental if done to carefully to return foot to normal shape
Good trimming technique - Does nothing
Bad trimming technique - causes lameness
Whole flock inspection without trimming could reduce lame sheep by early treatment
Sheep feet become overgrown beause they are infected, they don’t get infected because they are overgrown
What is the 5 point control plan for sheep lameness?
- Avoid spread of infection (in gateways, at gatherings) (wet muddy area) (seperate lame animals)
- Treat individuals quickly and effectively
- Quarantine bought-in sheep
- Cull out persistent offenders
- Vaccinate to protect against foot rot
What are the key aspects of footbathing to manage scald/footrot in lambs?
- Good facilities - not straight to mud
- Clean feet before footbathing
- Stand on hard surface after footbathing
- Follow the instructions of the products used -
- 10% zinc sulphate for at least 2 minutes
- 3% (no stronger!) formalin as a walk-through
- Use - for lambs with scald or to control spread after handling
- NB foot-bathing is NOT EFFECTIVE to treat footrot
What are the principles behind treating sheep with lameness?
Treat quickly:
* Catch lame sheep quickly (within 3 days) – even if mild catch, inspect and diagnose.
* Treat appropriately
* Mark and record
* Avoid trimming
* Topical antibiotic - Spray, allow to dry & re-spray
AND
* Injectable antibiotic
Essential for foot rot & CODD
What are the principles behind quarantine to control sheep lameness?
what is this trying to control?
to avoid CODD & virulent foot rot
* Buy in from known source
* Reject lame sheep
* Ask about vendors vaccination status & lameness policy
Quarantine incomers for 3 weeks
* Inspect all feet and footbath / treat on arrival
* Treat promptly if become lame
* Discuss vaccination
* Only add to flock once you are sure
Quarantine for at least 2 weeks
What are the principles behind culling lame sheep?
- Persistently lame ewes spread lameness & cost £££s
- Don’t breed from these sheep
- Keep records of all lame sheep!
2 or 3 strikes and she is out…….
What tpye of lameness in sheep can you vaccinate against?
What are the guidelines for using this?
Multivalent vaccine containing all UK strains of foot rot
Discuss strategic use and timings:
* Two doses (6 weeks apart & a single dose every year just before the risk period for that farm).
Very useful as part of a control package - still need to catch and treat lame sheep
NB 1. Can cause swelling & colouring of wool at injection site – care with show sheep!
2. Due to the same carrier system, moxidectin 1% should not be given to sheep previously vaccinated with Footvax
