Lameness causing foot lesions - Aetiology, treatment + risk factors Flashcards
What are infectious causes of lameness?
- Digital dermatitis
- Interdigital Phlegmon (foul in the foot)
- Interdigital dermatitis
- Heel horn erosion
What does digital dermatitis cause? Aetiology?
- Mortellaro disease
- Hairy heel warts
- Strawberry foot
- Aetiology = Treponema denticola, T. medium, T. phagedenis
What is seen with digital dermatitis?
- Painful, reddened area above interdigital cleft, between heel bulbs
- Erected hair around the lesion
What are non-infectious causes of lameness
- White line
- Bruising
- Ulcers
What is sole bruising?
- Contusion of the corium
- Pressure from pedal bone
- External pressure (eg from stones), especially when soles are thin
What are sole ulcers?
- A more severe manifestation of bruising (mainly caused by trauma/ contusions of the corium from the of the pedal bone)
- Disrupted sole horn production
- Exposure of the corium
What part of the hoof produces the sole horn? What protects it?
- Corium
- Protection = digital cushion
What is treatment of sole haemorrhage / bruising or sole ulcers?
- Foot trimming
- Block unaffected claw - if both claws affected don’t block
- NSAIDs
What are white line lesions?
- Separation, stones/ manure
- Associated with shearing/ sideways forces on the feet
- Claw overload, contusions of the corium could also be associated
- Abscess formation
What is treatment of white line?
- Functional trimming
- Remove detached horn,
- Block unaffected claw
- NSAIDs
- Antibiotics
With corrective foot trimming what are the aims?
- Remove all loose, undermined + necrotic horn
- Avoid damage tot he peripheral corium tissues
- Adjust weight bearing
- Change microenvironment from anaerobic to aerobic
What does use of a block do?
- Prevent repeated trauma
- Reduce pain by elevating claw
- Promote uninterrupted healing
What are risk factors for lameness?
- Cow comfort
- Stocking density
- Feed barrier space
- Milking frequency, duration, cow flow
- Floor surface
- Tracks
- Animal handling
- Foot shape / claw overgrowth
- Over trimming
- Calving
- Thin Cows
- Nutrition
- Age / Parity
How does cow comfort affect lameness?
- Lying / standing on concrete times - need comfortable cubicles - big enough + bedded
- Bedding material - deep sand = best choice
How does overcrowding cause increased stocking density?
- Increased standing times + more aggressive interactions
How does milking frequency, duration + cow flow affect lameness?
- 3 times milking = increased standing / walking times
- Long waiting combined with overcrowding in collecting yard = problem
- Bad cow flow / sharp corners
What is bad considering flooring? How can you improve flooring
- Hard, wet/slurry, slippery
- Try putting rubber flooring - especially in parlours + keep clean
How do tracks increase lameness?
- Wet + muddy
- Sharp stones + gravel on surface
What can overtrimming do?
Predispose cows to lesions - thinner soles
How does calving increase lameness risk?
- Weakening of connective tissues of the claw suspensory apparatus = increased susceptibility to sole ulcers + white line disease
How does nutrition affect lameness?
- Acidosis, SARA + link to laminitis
- Deficiencies, biotin, protein content, lipids
- BCS!!
How does age / parity affect lameness?
- Older cows = more likely to be lame
- Repeatability of major lesions
- Calving is a risk factor anyway
How are transitioning cows more likely to become lame?
- Calving effects on ligaments
- Reduced DMI / feed intake = reduced digital cushion
- Increased weight bearing
- Diet changes
- Inflammation
What is control of claw horn disruption lesions?
- Identify risk factors + improve conditions
- Early Tx of clinical cases
- Routine foot trimming
- Transition cow + heifer management - BCS, space
- Genetic selection
- Monitor progress
What are other non infectious foot lesions?
- Interdigital hyperplasia
- Toe ulcer / necrosis
- Vertical wall crack
- Axial wall crack / fissure
- Deep digital sepsis
- Retroarticular abscess
- Corkscrew claw
What can cause interdigital hyperplasia? Tx?
- Chronic skin irritation =
-digital dermatitis
-interdigital dermatitis - Tx = surgical removal under regional anaesthesia when painful
What causes toe necrosis? Tx?
- Over wear / trimming of toe sole
- Infection causing osteomyelitis
- Tx = trim + block unaffected claw - partial / full digital amputation
What are vertical wall cracks? Tx?
- Sandcrack, non-painful, exposed corium + granulation tissue
- Tx = block unaffected claw, trim
What should be done with axial wall cracks?
- Remove detached horn / granulation tissue + block healthy claw
What can cause deep digital sepsis? What should be done?
- Untreated foul in the foot, complicated sole ulcers, untreated white line abscess, puncture wounds
- V painful
- Tx = amputation / euthanasia / arthrodesis
What is a retroarticular abscess? What should be done?
- Abscess above heel bulb, V painful over heel of one digit
- Tx = surgery - digital amputation
What causes corkscrew claw?
- Hereditary - regular trimming + cull
What are risk factors for digital dermatitis?
- Housing / Hygiene / Infection pressure - slurry, wet conditions
- Skin integrity
- External foot-trimmer
- Dirty hoof-trimming knives
- Poor biosecurity - buying in heifers
- Over crowding - increased standing times
- Parity + repeatability - once infected = more likely to get again
- Genetics
How is digital dermatitis controlled?
- Identify risk factors + improve conditions
- Genetic selection
- Early treatment of cases
- Footbathing - formalin, copper sulphate, zinc sulphate
- Vaccines?
How would you treat digital dermatitis?
- Clean + dry lesion
- Apply topical antibiotics
- NSAIDs
What is foul in the foot? Aetiology? What is seen?
- Foot rot - fusobacterium necrophorum
- Sweeling above the claws + Strong Odour
- V Painful!!
How is foul in the foot treated?
- Clean lesion
- Remove necrotic tissue
- SYSTEMIC Antibiotics
- NSAIDs
What is interdigital dermatitis?
- Milder infection of interdigital skin?
- Dichelobacter nodosus
- Can spread across heels = heel horn erosion
What is treatment of heel horn erosion?
- Foot trimming
- Topical antibiotics
