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Sheep 21: Foot lameness
Veterinary Medicine

Additional Veterinary Medicine Flashcards




Foot rot


Wet conditions/trauma of interdigital skin
Interdigital dermatitis
F. necrophorum penetrates stratum corneum
D. nodosus proteases cause hoof separation and allow the deeper

penetration of F. necrophorum
With virulent strains, under-running spreads from axial heel, laterally and

anteriorly under sole to abaxial wall and toe 

Foot rot epidemiology


  • D. nodosus only survives for a few days outside the feet of ruminants, up to 7 days in mud.

  •   Transmission requires mean daily temperatures 10C or more, and 2 or 3 months exceeding 50mm rainfall/month (Australian data)

  •   Virulent strains do not readily cause latent infections

  •   Persistent clinical lesions may occur under cool conditions 

Foot rot clinical signs


  •   Mixture of interdigital dermatitis, under-run heels and severe under-run hooves.

  •   It is not possible to differentiate clinically between interdigital dermatitis and the

    early stages of footrot, or between benign footrot and early virulent footrot.

  •   Mild strains result only in separation at the heels and back of the sole (benign

    footrot), while virulent strains can result in complete separation of the horn of the

    hoof wall and sole.

  •   Characteristic smell

  •   Chronic cases misshapen hoof, trapping dirt and inflammatory exudates

  •   Advanced footrot - extremely lame, recumbent for long periods, flystrike on foot

    and flanks 

foot rot diagnosis


  1. is it footrot? How virulent is it?

    •   Clinical examination of many individuals (?10-40)

    •   May need re-inspection after 2 weeks to assess progression

  2.   Main DDX OID, CODD 
footrot treatment

Topical treatment
o Gentle paring and application of oxytet spray (small numbers) o Footbathing

3% formalin, formalin concentrations exceeding 5% can result in foot damage and should be avoided.


10% zinc sulphate (extended period or frequent)
Clean feet (esp. formalin) and dry standing afterwards important Cure rates of up to 80% feet, but not great against advanced



o Therapeutic effect some respond to first injection, 50-100% to second injection.

Parenteral antibiotics i/m
o 85% or more cure rates, effective against advanced lesions o Paring not needed
o Dry conditions required 24hrs post treatment
o Oxytetracycline 20mg/kg or high dose Pen & Strep 

Control and prevention of footrot


  • If prevalence high, treatments as above to reduce number of infected animals.

  •   Aim of control is to achieve;

o Low incidence of footrot

o Low % of early lesions developing into severe lesions Based on footbathing and vaccination


  •   Two doses needed for protection

  •   Given before transmission period if possible, difficult to predict in UK

  •   4-6 months protection in UK breeds

  •   Reactions and reduced LW gain not ideal for fat lambs

  •   In many UK flocks, vaccination is targeted at specific high-risk groups of animals,

    such as rams before mating 


  •   To stop development of early interdigital lesions into severe lesions

  •   To reduce environmental contamination

  •   During transmission periods (?from May if not too dry) weekly or fortnightly

  •   Some protection from re-infection for 24 hours after bathing, and no records of

    sheep becoming infected from pasture after 24hrs rest therefore move to “clean” pasture (rested two weeks) after treatment probably of minor importance in control (c.f. eradication)

  •   Foot paring has no role in preventing footrot 

Foot rot selection for resistance


Resistance to footrot appears is moderately hereditable and breeding of resistant sheep by selective culling could be considered as a potential control strategy. However, while breeding of resistant sheep is a genuine possibility, the value of this strategy is limited by the stratified system of sheep production in the UK. 

Foot rot eradication


Footrot can be eradicated from a farm by de-stocking for 7 days and re-stocking with clean sheep
Eradication from a
flock involves intensive effort during a non-transmission phase when all virulent footrot infections should be clinically apparent, and all pastures safe for clean sheep (c.f. control programs, when effort is concentrated in the transmission period). The identification of such periods in the UK is problematic.

  •   Prevalence should be 5% or lower

  •   All feet examined

  •   Cases treated or culled must be isolated if transmission possible

  •   Inspection repeated once or twice

  •   Non-responders culled

  •   Avoid re-introduction

o Purchase clean replacements impossible in UK
o Quarantine extended periods needed to eradicate footrot in the

purchased sheep often not practical o Closed flock

Climate change leading to drier summers may make eradication a practical

option over areas of the UK 

Interdigital dermatitis ( scald)


(45% of lameness)
Scald is a major cause of lameness in itself; in addition it is also the first stage in the pathogenesis of footrot and septic pedal arthritis.


F. necrophorum infection alone - does not require D. nodosus. It is clinically indistinguishable from benign footrot, caused by F. necrophorum and benign strains of D. nodosus, and early virulent footrot.


Interdigital dermatitis epidemiology


Moist conditions and trauma caused by long wet grass is often the predisposing factor, particularly in lambs. Straw bedding may play a similar role in outbreaks in housed ewes. Typically many animals in the flock are lame in one or more foot. In extreme cases, 90% of the flock can be affected 

interdigital dermatitis clinical signs


  •   Interdigital skin inflamed and swollen

  •   Layer of white necrotic material

  •   May progress to erosions of ID skin tissue

  •   No under- running of horn, no smell

  •   Lameness can persist for several months if untreated 

interdigital dermatitis treatment and control

Individual cases - oxytetracycline sprays 77



o Move to dry pasture ideal but unlikely
o Management of areas around troughs and gates etc.
o 10% zinc sulphate solution or 3% formalin footbath, followed by dry

standing for 1 hour
o Repeat 5 - 14 day intervals throughout the risk period 

Ovine digital dermatitis ( new variant foot rot)


A virulent, rapidly spreading foot disease similar to digital dermatitis in cattle has been described in sheep of all ages. Appeared widespread in early 2000’s. Prevalence seems to have decreases in recent years.

An association has been made between the disease and the presence of motile spirochaetes. However, motile spirochaetes may also be present on the lower limbs of healthy sheep. In some cases proliferative lesions at the coronary band appear similar to orf, but orf virus has not consistently been identified in scab material from the lesions.


In some areas up to 50% of sheep flocks have been affected 

ovine digital dermatitis clinical signs


  •   High morbidity rate (up to 70%)

  •   Severe lameness

  •   Initially, full thickness skin ulceration at the coronary band (c.f. scald and footrot)

  •   Hoof wall under-run from coronary band and often shed to expose the sensitive

    laminae which may bleed profusely.

  •   1 cm diameter circular areas of hair loss and ulceration sometimes seen on skin

    below the fetlock joints.
    Often cases of virulent footrot/mixed infections in same flock


    F. necrophorum and D. nodosus often present, and may increase severity. Formalin footbaths may increase the severity 

Ovine digital dermatitis treatment and control


  1. Treatment and Control

    •   Lesions heal quickly after topical treatment with oxytetracycline aerosol sprays

    •   Response to foot trimming and foot-bathing in formalin or zinc sulphate is poor.

    •   Footbathing for 20 minutes in tylosin or lincomycin antibiotic solutions followed by

      dry standing appears to be effective for prevention and treatment of ovine digital dermatitis (for example: Tylan soluble, Elanco, at a rate of 1 g of powder per litre of water).

    •   Individual cases may benefit from systemic antibiotic treatment. 

Other lameness diseases


  1. FOOT ABSCESS (Septic pedal arthritis) - failure to manage lameness

    TOE ABSCESS (White line abscess) - pairing



Foot Abscess


Aetiology and Pathogenesis
Interdigital dermatitis and/ or footrot

invasion by other pyogenic bacteria (e.g. A. pyogenes)
Distal interphalangeal joint capsule lies close to interdigital

septic arthritis of P2\P3 joint


foot abscess clinical signs


Usually one foot
Severe pain and lameness +/-

recumbency, muscle atrophy

Heat, swelling and discharging sinuses at coronary band + interdigital space

Widening of interdigital space +/- collateral ligament rupture

Rapid weight loss

Pregnant ewes-> pregnancy toxaemia( not eating, recumbant) 

Rams -> poor reproductive performance

Annual incidences of 2% common, up to 10%

failure to manage interdigital dermatitis

use of concentrated formalin footbaths 

Treatment for foot abscesses


Antibiotic treatment and flushing joint unsuccessful

Surgical removal of digit
Long term prognosis excellent

Cases may heal by arthrodesis if left for several


Radical curettage of joint has been successful

intra-articular antibiotic implants and casting


Digit amputation


Tourniquet above hock or below carpus

Clip and scrub over superficial vein
Laterally on hind limb (recurrent tarsal)

Medially on forelimb (cephalic)

5ml local anaesthetic into superficial vein, 19g 1inch needle

Use of a local anaesthetic with adrenaline - not caused any practical problems

Anesthetised in 5 minutes, test by pricking heel

Clean foot and interdigital skin

Interdigital cut

Insert embryotomy wire - remove digit 15above the horizontal

Cut through the middle of P2

Sharply debride any remaining infected tissue

Apply oxytet spray, non-adherent dressing

and well padded pressure bandage
Long acting oxytetracycline i/m if needed

Change for lighter dressing after 48 hours

Change again after around 4-5 days

This dressing removed after 5 days 

Toe abscess- white line abscess


Aetiology and Pathogenesis
Outbreaks sometimes seen in autumn, in wet and muddy

Culture often yields environmental bacteria including F.


Gain access to the sensitive laminae through small fissures
Shelly toe and overgrowth due to footrot etc also predispose

Clinical signs:

Sporadic cases of acute onset, severe lameness, usually one digit

Often non weight-bearing.

Pain on pressure on overlying

hoof wall

+/- swelling or a discharging sinus at coronary band

Abscess at white line towards the toe


treatment for toe abscess


Careful paring to reveal and release the trapped pus

Removal of under-run horn

Avoid excessive paring, may lead to;

Granuloma formation
Septic pedal arthritis 

shelly toe

- separation of the superficial hoof wall close to white line at the toe

- commonly seen in sheep grazing on lush pasture

- lameness when impacted with soil and faecal material

- pressure on sensitive tissues


Toe granuloma treatment


Do not recover without treatment
Overgrown horn pared (local anaesthesia facilitates this) Granulomatous tissue needs to be cut back

Bleeding prevented by;
heat cautery of the base
repeated pressure bandaging 

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