1.4 Production Animal Lameness 3 Flashcards
What are the major ovine conditions causing lameness?
mentioned in lecture
hoof:
- scald
- footrot
- contageous ovine digital dermatitis
- shelly hoof
- foot abscesses
- strawberry footrot
joint:
- spetic pedal arthritis
- joint ill
mid-upper limb:
- fractures
- upper limb lameness
What is ovine scald?
- also called benign foot rot
- Scald is caused by the bacterium Dichelobacter nodosus, which also causes severe footrot
- Foot scald involves inflammation, while foot rot involves necrosis
- clinical signs: inflammation of interdigital skin, may have grey/white scum and foul smell, common cause of lameness in lambs
- treatment: topical oxytetracycline; in adults, topical oxytetracycline & systemic oxytetracycline
- prognosis: good
- prevention: control of footrot? regular footbathing? provoking factors include wet conditions and long, rough grass
What is the causitive agent of ovine footrot?
Dichelobacter nodosus (sensitive to penicillin): Gram -ve anaerobe
What is the pathogenesis of ovine footrot?
fecal shedding of Dichelobacter nodosus by some sheep, chronically infected feet will act as a reservoir of infection and co-infection with Fusobacterium necrophorum occurs
What are the clinical signs of ovine footrot?
More severe form of foot scald.
Footrot progresses from scald when the infection progresses from the soft tissues of the interdigital skin to underrun the hoof (begin to infect the later beneath the hoof capsule); if neglected, the hoof becomes separate from the soft tissues of the toes.
characteristic smell, underrunning of hoof horn, and grey/white scum
How do you treat ovine footrot, and what is the prognosis?
do NOT trim
- systemic and topical oxytetracycline, Macrolides for refractory cases, +/- NSAID (no evidence)
good prognosis if treated promptly; delayed treatment can give rise to toe granuloma
How to you control and prevent ovine footrot at the level of the herd?
5 point plan: avoid, vaccinate, treat, quarantine, cull (2/3 strikes)
footbath: NEVER perform on lame sheep (preventative only)
- 3% formalin (submerge twice): painful, carcinogenic
- 10% zinc sulphate (stand in for 10 minutes): not as irritant
dry standing for 30 minutes after: if done poorly can increase the chance of footrot
What is contageous ovine digital dermatitis (CODD)?
Same as digital dermatitis in cows: infection with treponeme bacteria
- except in sheep causes ulcer at coronary band, underrunning of hoof horn, foul smell, hair loss: 3rd most common cause of lameness
- can be difficult to differentiate from footrot
What is the treatment and prognosis of contageous ovine digital dermatitis?
DO NOT TRIM
- systemic LA amoxicillin or
macrolides - topical oxytetracycline (does not appear to be particularly sensitive to systemic oxytetracycline: one reason it should be differentiated from footrot)
delayed treatment can lead to toe granuloma, deformed hoof, and deformation of pedal bone
prognosis is good if treated promptly
What is the difference between CODD and ovine footrot?
CODD starts at the coronary band (hoof – hair junction) and unlike footrot does not involve the interdigital space; infection spreads down the foot separating the horn from the underlying sensitive structures; ultimately the whole hoof capsule may fall off
- CODD: treponeme bacteria
- ovine footrot: Dichelobacter nodosus +/- Fusobacterium necrophorum
What is shelly hoof?
and how do you treat it
a complex disease with unknown etiology (nutrition, genetics, etc.) leading to the separation of the wall and sole horn of the ovine foot
- forms a pocket and allows impaction with soil and stones
treat by paring off the loose horn
good prognosis: animals usually only mildly lame, but often recurs in affected animals
What is the pathogenesis of ovine foot abscesses?
penetration of white line (with bacteria), incombination with genetics, dietary and underfoot conditions
- often very lame, may burst out at coronary band
How do you treat ovine foot abscesses?
pare foot to release pus, ± systemic antibiotics
- prevention: improve underfoot conditions, correct predisposing factors (nutrition, underfoot conditions, etc.)
good prognosis
How do you differentiate an abscess from a toe granuloma in sheep?
a toe granuloma will present as a red/pink “polyp” of moist granulation tissue surrounded by a collar of loose horn, whereas a foot abscess is likely to present as a bulging of the hoof without new tissue formation (and is filled with pus)
What is the pathogeneis of toe granuloma in the sheep?
chronic inflammation due to
- exposure of corium
- untreated footrot / CODD
- over-trimming
What is strawberry footrot?
it is due to a co-infection with orf virus (parapoxvirus genus) and D. congolensis
This causes proliferative granulation tissue around the lower limb that bleeds easily (has NOTHING to do with footrot)
What is septic pedal arthritis?
infection of the distal interdigital paryngeal joint (DIPj) causing local arthritis
- may be extension from foot or due to direct penetration (e.g. thorn)
- severely lame, heat and swelling above coronary band (this is where DIPj is)
- discharging tract possible
How does laminitis present in goats?
- due to differences in management (goats often on very high concentrate diets)
- the goat may develop ‘platform’ soles that are very high
- the hoof is often very hard and difficult to trim
- may see bruising within hoof horn
- acute disease less commonly encountered: heat, sudden onset lameness may be associated with ruminal acidosis, metritis etc.
What is treponeme-related disease in goats?
- thought to be due to treponemen infection of laminitis-affected feet
- clinical appearance (variable): (like sole ulcers or non-healing wall ulcers in cattle; can be CODD-like)
- treatment: cull, treat with LA amoxicillin and bandaging, digit amputation
- prevention: prevent laminitis, culling of affected goats, improve shed hygiene, regular footbathing
Explain pig foot anatomy.
Pig lameness chart for reference.
What causes of pig lameness are common in small scale producer and pet pigs?
- arthritis
- overgrown toes
- axial wall cracks
- sole punctures from foreign body
What is Erysipelothrix rhusiopathiae and how does it contribute to swine lameness?
- Known for its diamond skin lesions, but chronic form results in lameness
- Typically affects pigs >12 wks
- Clinical Signs: skin lesions (diamonds), pyrexia, stiff walk, vegetative endocarditis, single limb lameness, joint swellings, chronic cases ‘hunched’ posture
- Treatment: Penicillin/Amoxicillin and NSAIDs
What is bush foot and how does it contribute to swine lameness?
Multiple bacteria sp.
- proliferation of environmental contaminants in the hoof leads to abscessation which ultimately swells and bursts producing what is commonly recognised as bush foot
- Investigate flooring and housing
- Prognosis: poor for individual on commercial setting
- Treatment: broad spectrum antibiotic and NSAIDs OR Euthanasia
What is Mycoplasma hypsynoviae and how does it contribute to swine lameness?
Cause of “mycoplasma arthritis”
It is a respiratory disease, the organism being found in the upper respiratory tract nose and tonsils. It may be present in some herds and cause no clinical signs and yet in others cause severe disease.
It is spread by droplet infection. It invades the joints and tendon sheaths of susceptible animals and causes lameness and swelling. Most mother’s pass immunity to offspring: infection most common once MDAs wear off (week 10)
- Affects growers (> 10wks) and young adults
- Often newly bought in pigs to farms
- Clinical Signs: near signs, No pyrexia, sudden onset lameness, unilateral or multi-limb, response to lincomycin or tiamulin
- Diagnosis: PME, Culture of joint fluid (N.b. False -ve occur)
- Treatment: Antibiotic (tulathromycin, lincomycin or tiamulin), NSAIDs
- Prognosis: poor
