Lameness in sheep

• What is the most common cause of lameness in sheep?

  Scald/ strip/ interdigital dermatitis.

  Scald is an earlier presentation of foot rot.
• What are the clinical signs of scald?

  Inflammation of the skin between the claws.

  Reddening.

  Paste

  White/grey scum.

  
• What are the clinical signs of foot rot in sheep?

  Smell

  Grey ooze

  Under running of hoof horn near to skin between claws - this is the main differentiating factor between scale and foot rot.
• How does CODD (contagious ovine digital dermatitis) present?

  Highly invasive and painful starting with a lesion at a coronary band.

  Rapid invasion and underunning of hoof wall.

  May be no involvement of the interdigital space.

  Often >30% of flock in first year and then settles to ~2% lame sheep.

  Many control approaches the same as for footrot.

  
• What is the treatment for CODD (contagious ovine digital dermatitis)?

  Spirochaetes/treponemes involved but often mixed infection with D nodosus.

  Requires long acting injectable antibiotic - Amoxicillin, Oxytetracycline, Macrolides if no response to first 2.

  Only treat the lame sheep, promptly (within 3 days of identifying lameness).
• What are the factors linked to lower levels of CODD (contagious ovine digital dermatitis)?

  Not purchasing sheep.

  Isolating sheep returning to the farm.

  Avoiding use of summer grazing away from the farm.

  Preventing ewes from mixing with neighbouring flocks.

  Examine feet prior to purchase.
• Toe granuloma in sheep

  Inflamed granulomatous tissue coming out from under the horn.

  From snipping into sensitive part of the toe or chronic unresolved footrot, often due to over trimming.

  Very difficult to treat.

  Don’t cut it off without a tourniquet or will bleed profusely.

  Use local anaesthetic.

  Have a habit of recurring.

  
• What is white line disease?

  Defect on abaxial surface of the horn at the junction of the wall and the sole.
• White line disease - shelly hoof

  Hoof comes away from the foot.

  Soil or debris accumulates laterally at the 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.

  
• White line disease - toe abscess

  Usual presentation is that of sudden onset extreme lameness with pain and heat but no obvious swelling.

  Pus tracks up and breaks out at the 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.

  
• Foot abscess in sheep

  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.
• How should you treat sheep with footrot?

  Trimming horn actually delays healing:

  Administer antibiotics to clear D.nodosus
• Is routine foot trimming in sheep detrimental?

  Appear to neither be beneficial nor detrimental if done carefully to return the foot to a normal shape.

  Over trimming can lead to lameness.
• What is the 5 point plan for sheep lameness?

  Avoid spread of infection (in gateways, at gatherings) - bacteria spread in wet muddy soiled areas.

  Treat animals quickly and effectively - catch lame sheep within 3 days, topical antibiotic spray, systemic antibiotics.

  Quarantine - to avoid CODD and virulent foot rot, reject lame sheep.

  Cull - persistently lame ewes spread lameness and are expensive, do not breed from these sheep.

  Vaccinate against footrot - multivalent vaccine containing all UK strains of foot rot.