Small Ruminants: Lameness in Sheep Flashcards
Where does most lameness in sheep occur?
Most lameness in sheep is in the foot
What are the main diseases and foot lesions that cause foot lameness?
Foot rot- benign footrot, interdigital dermatitis, scald, virulent
CODD
White line disease
Toe granuloma
Foot abscess
Interdigital hyperplasia
Overgrown or misshapen claws
Foreign body
Soil balling
What non-foot diseases are associated with lameness?
Arthritis- infectious, osteo
Fractures
Muscular
Neurological
Always confirm diagnosis youself
What % of flocks are affected by benign footrot/ID/scald
97%
either on its own or part of mixed infection
flock level problem
How does benign footrot/ID/scald appear?
What is the main pathogen?
- Lame
- Interdigitsl skin inflamed ±discharge
- No horn under running (not coming off)
- Damage to skin may predispose to bacterial infection (damp, frost, thistles)
Dichelobacter nodosus- main pathogen
RWhen are outbreaks of benign footrot/scald/ID?
How can lesions progress?
Outbreaks in groups of growing lambs
Lesions can progress to footrot with underrunning of horn depending on sheep, treatment
Risk factors the same a footrot
What is footrot?
Interdigital dermatitis with
progressive under-running of sole of hoof horn starting at medial aspect of sole and progressing laterally
Grey necrostic pungent smelling horn
What are the characteristics of dichelobacter nodosus?
- Aetiological agent of foot rot
- Facultative anaerobe
- Survives 7 days in environment
- Present in normal sheep
- Virulence- fimbrae, proteases
Fusobacterium necrophorum- anaerobe, gut, faeces, often found in foot rot
What are the characteristics of dichelobacter nodosus?
- Aetiological agent of foot rot
- Facultative anaerobe
- Survives 7 days in environment
- Present in normal sheep
- Virulence- fimbrae, proteases
Fusobacterium necrophorum- anaerobe, gut, faeces, often found in foot rot
What are the risk factors associated with ID and foot rot?
- Warm
- Wet under foot conditions
- Muddy
- Housing
- Gathering
- Genetics
How is ID treated?
Topical treatment-
* oxytet spray (dry before grazing)
* Footbathing in antiseptic- formalin, zinc sulphate
Systemic antibiotics- LA oxytet
What is needed with foot-bathing for ID?
- Antiseptic needs to be exposed to inter-digital area for 2 mins approx
- Clean feet before hand
- Correct concentration
- Dry standing afterwards
How is footrot treated?
- Treat as quickly as possible
- Isolate lame sheep
- Treat individuals/groups
- Injectable LA- oxytet/amoxicillin
- May require repeat reatments
- Do not trim feet unless necessary
Should feet be trimmed before treatment?
Farmers often treat after trimming- expose air
But studies show not necessary- trimming not reccomended
What does CODD stand for?
Contagious ovine digital dermatitis
Severe lameness
How does CODD appear clinically?
Ulcerative or proliferative lesion starts at coronary band
Progressive under-running of hoofwall downwards
Hoof sloughs off
Often mixed infections
What grade of CODD is this?
Grade 1- coronary band lesion only
What grade of CODD is this?
Grade 2- <50% of horn capsule seperated
What is the difference between grade 3 and 4 CODD?
Grade 3- 50-100% hoof capsule off
Grade 4- healing but still active lesion present
What is grade 5 CODD?
Healed
What is the aetiology of CODD?
Treponeme bacteria identical to those causing digital dermatitis in cattle,
T. medium, phagedenis, pedis
Dichelobacternodosus and fusobacterium necrophorum also found
What are the risk factors for CODD?
Seasonal trend late summer/early autumn
Large flock size
Lowland pasture, lush pasture, poached pasture
Many cases thought to develop from footrot/ID
What is the treatment of CODD?
- Isolate
- Prompt
- Responds to ABs- LA amoxicillin
- Usually require repeat doses
- Treat until cure
- Macrolides licensed for sheep
How should foot disease be managed?
Generally
- As soon individual animal is seen lame it should be treated, welfare, disease spread
- Flock level ID- five point plan
- CODD/Footrot/Scald closely related, control all
- Biosecurity- prevent entry
- Reduce disease challange- hygiene ventilation, drug treatments
What is the 5 point plan to manging foot infectious disease?
- Vaccinate twice yearly- footvax
- Treat lame sheep quickly
- Biosecurity
- Environmental challenge
- Cull chronically lame
How is footrot vaccinated for?
- Footvax
- Useful for farms that struggle
- Oily adjuvant injection site lumbs
- Not used prior to shearing
- Not used close to lambing time
- Not use if sheep had moxidectin 1%
How can lame sheep be treated early?
- Prompt individual isolation/treatment
- Worth considering going through whole flock
- Treatment with injectable ABs- LA oxytet/amoxicillin, macrolides
- Scald- topical abs
- Repeat until clinical cure
How should biosecurity of foot diseases be controlled?
- Bought in sheep- don’t buy in new diseases or new strains of disease, consider where bought from, isolate, treat anthelmintic resistance, treat scab
- Check for foot lesions- to pick up early
- Footvax farm- treat all sheep with footvax
- Find CODD/Foot rot- return?, whole group ABs
How should environmental hygiene be controlled for CODD and footrot?
- Keep handling areas as clean as possible
- Foot trimming equipment clean and disinfect
- Wet muddy areas in the fields and housing can be good areas for disease to spread (bedding dry)
When shoud sheep be culled for lameness?
- Sheep had 2-3 cases of lameness then cull
- Harbour infection in feet, spread in the flock
- Production- less likely to get pregnant, rear healthy lambs
- Breeding own replacements
- What is shelly hoof also known as?
- What is the aetiology?
- Why does it not always cause lameness?
- White line Disease
- Aetiology- unknown, genetics, nutrition
- Dont cause lameness unless sensitive tissue affected- impaction with stones, mud, abscess formation
What does the following image show?
White line abscess
How can white line disease be treated?
No infection just separation of sole from wall- leave, can carefully trim out area of separation
Abscess- heat, pain swelling, trim if necessary
What condition is this image showing?
Soil Balling- remove, clean, topical ABs
What is this conditions what can cause it and how is it treated?
Toe Granuloma
Caused by over trimming
Treatment- IV regional anaesthesia, cut back grannulation tissue, cauterise (disbudding iron)
What condition does this image show, how is it treated?
Interdigital hyperplasia- breed related, excessive ID skin
Often secondary infection- treat and clean area- ABs
How do animals with laminitis show clinically?
How is it treated?
Affected animals are reluctant to stand, when standing, affected animals hold all limbs close together under the abdomen, warm digits (pulse)
Hooves develop horizontal grooves that take months to grow out
Excess access to high energy cereal-based feed and acute disease of metritis/mastitis can predispose
Treatment- NSAIDs, Address underlying cause
What is the cause of pedal joint abscess?
What are the clinical signs and treatment?
Cause- consequence of extention of interdigital infection into the distal interphalangeal joint structures, pus tracks abaxially across the distal interphalangeal joint to emerge at abaxial coronary band
CS: animals are severly lame, foot is swollen, interdigital space is widened, purulent dischaging sinus maybe
Treatment- flush and ABs, digit amputation
- What is digit amputation?
- What sedation and anaesthesia is used?
- Disarticulation between P1 and P2
- Sedate- Xylazine
Local- IV regional 5-10ml procaine or ring block
Describe the process of digit amputation?
- Clip, clean and prepare foot
- Disarticulate between P1/P2
- Bandage
- Change after 3/4 days
- ABs, NSAIDs
When should sheep not be foot trimmed?
When they have an infectoin
How should feet be trimmed?
Not much- only ever need careful cosmetic trimming
* If feet overgrown (often after housing)- are likely to self correct, don’t cause bleeding
* If white line abscess to allow drainage
What is strawberry foot?
Proliferative scab lesion in distal limbs
Usually or an dermatophillus
Systemic and topical ABs and move to dry fields
White element deficiency can cause lameness?
White muscle disease- selenium and vitamin E deficicieny
stiffness and reluctancy to move
How is white muscle disease diagnosed and treated?
Dx- raised glutathione peroxidase levels in blood
Tx- Vit E/Selenium supplementation
What bone diseases can cause lameness?
Fractures
Rickets
Arthritis
How do fractures in sheep normally present?
How is it treated?
- Sudden onset of lameness of varying severity but commonly non-weight bearing
- Pain, swelling and crepitus may accompany the site
- Pain swelling, haemorrhage and exposed bone
- Tx- Casting, confinement, surgery, often successful in young animals
- How does rickets present?
- What causes it?
- How is it diagnosed and treated?
- Lameness, stiffness, swollen joints, angular limb deformities
- Vitamin D deficiency
- Dx- blood vitamin D levels, Tx- vitamin D/caclium supplements
What are the main two types of arthritis that affect sheep?
Infectious
Degenerative joint disease
What can cause infectious arthritis?
Neonatal infections- strep dysgalactaie
Tick pyemia- staph aureus infection
Erysipelothrix rhusiopathie
- Where does DJD most commonly occur?
- How does the joint present?
- How can diagnosis be confirmed
- Elbow joint most commonly affected, tarsal, carpal and stifle joints
- Thickening, effusion, pain and restricted movement of joint
- Radiography can be used
