Infectious and non-infectious (mixed) claw horn lesions in cows

Mixed lesions usually occur when a claw horn lesion becomes infected. However, an infection can lead to claw horn lesions, so prompt treatment is essential.

Success factors

Treating the following lesions rely on differing combinations of all four success factors:

• Low infection pressure
• Good hoof shape, horn quality and digital cushion
• Early detection and quick, effective treatment of lame cows
• Low forces on the feet (good cow comfort and cow flow)

Any lesion caused by an infectious agent could spread on contaminated equipment from cow to cow. It's therefore important that this equipment is properly disinfected. 

Remember, your vet is there to support you, particularly in difficult cases; always consult them if you're unsure.

Secondarily infected lesions

These include white line disease (WLD) and sole ulcers (SU).

Description

• These are lesions which do not heal despite competent trimming and blocking
• The primary lesion is usually a claw horn lesion which has become secondarily infected, typically with digital dermatitis bacteria
• Toe necrosis is a separate example of a non-healing lesion, where the tip of the pedal bone has become infected
• Veterinary attention is necessary for non-healing lesions (unless culling) as surgical debridement or digit amputation are the treatments of choice, which both require local anaesthesia

Typical risks

• These conditions stem from an initial claw horn lesion, so attention to those risk factors is important
  Associated success factors: 2 and 4
• Non-healing lesions/difficult-to-cure lesions often involve secondary digital dermatitis infection on the exposed corium (quick), so attention to infection pressure is important. Other bacteria are involved too
  Associated success factors: 1
• Slow reaction to treat the lesions, or ineffective initial treatment, is often the underlying reason why claw horn lesions become infected
  Associated success factors: 3

White line abscesses, under-run sole and wall ulcers

• White line disease with infection causing pus
• Pus usually eventually escapes (‘bursts out’) at the coronary band or the heel bulb if not treated promptly

Under-run sole

• These occur most commonly from a white line abscess whereby build-up of pus has caused separation of the sole horn from the underlying corium
• May also be secondary to infected sole ulcers, again with build-up of pus. Sometimes multiple layers of under-run soles (or ‘false soles’) occur

Wall ulcer

This is the colloquial term for a white line abscess which has burst out at the coronary band, exposing the underlying corium; often become secondarily infected and become a non-healing lesion, sometimes with protruding granulation tissue (‘proud flesh’)

Typical risks

• These conditions all (usually) stem from an initial white line disease, so all the factors are important
  Associated success factors: 2 and 4
• Infected white lines with delayed healing can be associated with superimposed DD infections
  Associated success factors: 1, 3 and 4
• Slow detection and treatment of early lameness
  Associated success factors: 3
• Poor treatment protocol or technique
  Associated success factors: 3
• Poor acclimatisation to concrete floors
  Associated success factors: 2