Lameness causing foot lesions - Aetiology, treatment + risk factors

Question 1

What are infectious causes of lameness?

Answer 1

• Digital dermatitis
• Interdigital Phlegmon (foul in the foot)
• Interdigital dermatitis
• Heel horn erosion

Question 2

What does digital dermatitis cause? Aetiology?

Answer 2

• Mortellaro disease
• Hairy heel warts
• Strawberry foot
• Aetiology = Treponema denticola, T. medium, T. phagedenis

Question 3

What is seen with digital dermatitis?

Answer 3

• Painful, reddened area above interdigital cleft, between heel bulbs
• Erected hair around the lesion

Question 4

What are non-infectious causes of lameness

Answer 4

• White line
• Bruising
• Ulcers

Question 5

What is sole bruising?

Answer 5

• Contusion of the corium
• Pressure from pedal bone
• External pressure (eg from stones), especially when soles are thin

Question 6

What are sole ulcers?

Answer 6

• 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

Question 7

What part of the hoof produces the sole horn? What protects it?

Answer 7

• Corium
• Protection = digital cushion

Question 8

What is treatment of sole haemorrhage / bruising or sole ulcers?

Answer 8

• Foot trimming
• Block unaffected claw - if both claws affected don’t block
• NSAIDs

Question 9

What are white line lesions?

Answer 9

• Separation, stones/ manure
• Associated with shearing/ sideways forces on the feet
• Claw overload, contusions of the corium could also be associated
• Abscess formation

Question 10

What is treatment of white line?

Answer 10

• Functional trimming
• Remove detached horn,
• Block unaffected claw
• NSAIDs
• Antibiotics

Question 11

With corrective foot trimming what are the aims?

Answer 11

• Remove all loose, undermined + necrotic horn
• Avoid damage tot he peripheral corium tissues
• Adjust weight bearing
• Change microenvironment from anaerobic to aerobic

Question 12

What does use of a block do?

Answer 12

• Prevent repeated trauma
• Reduce pain by elevating claw
• Promote uninterrupted healing

Question 13

What are risk factors for lameness?

Answer 13

• 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

Question 14

How does cow comfort affect lameness?

Answer 14

• Lying / standing on concrete times - need comfortable cubicles - big enough + bedded
• Bedding material - deep sand = best choice

Question 15

How does overcrowding cause increased stocking density?

Answer 15

• Increased standing times + more aggressive interactions

Question 16

How does milking frequency, duration + cow flow affect lameness?

Answer 16

• 3 times milking = increased standing / walking times
• Long waiting combined with overcrowding in collecting yard = problem
• Bad cow flow / sharp corners

Question 17

What is bad considering flooring? How can you improve flooring

Answer 17

• Hard, wet/slurry, slippery
• Try putting rubber flooring - especially in parlours + keep clean

Question 18

How do tracks increase lameness?

Answer 18

• Wet + muddy
• Sharp stones + gravel on surface

Question 19

What can overtrimming do?

Answer 19

Predispose cows to lesions - thinner soles

Question 20

How does calving increase lameness risk?

Answer 20

• Weakening of connective tissues of the claw suspensory apparatus = increased susceptibility to sole ulcers + white line disease

Question 21

How does nutrition affect lameness?

Answer 21

• Acidosis, SARA + link to laminitis
• Deficiencies, biotin, protein content, lipids
• BCS!!

Question 22

How does age / parity affect lameness?

Answer 22

• Older cows = more likely to be lame
• Repeatability of major lesions
• Calving is a risk factor anyway

Question 23

How are transitioning cows more likely to become lame?

Answer 23

• Calving effects on ligaments
• Reduced DMI / feed intake = reduced digital cushion
• Increased weight bearing
• Diet changes
• Inflammation

Question 24

What is control of claw horn disruption lesions?

Answer 24

• Identify risk factors + improve conditions
• Early Tx of clinical cases
• Routine foot trimming
• Transition cow + heifer management - BCS, space
• Genetic selection
• Monitor progress

Question 25

What are other non infectious foot lesions?

Answer 25

* Interdigital hyperplasia * Toe ulcer / necrosis * Vertical wall crack * Axial wall crack / fissure * Deep digital sepsis * Retroarticular abscess * Corkscrew claw

Question 26

What can cause interdigital hyperplasia? Tx?

Answer 26

* Chronic skin irritation = -digital dermatitis -interdigital dermatitis * Tx = surgical removal under regional anaesthesia when painful

Question 27

What causes toe necrosis? Tx?

Answer 27

* Over wear / trimming of toe sole * Infection causing osteomyelitis * Tx = trim + block unaffected claw - partial / full digital amputation

Question 28

What are vertical wall cracks? Tx?

Answer 28

* Sandcrack, non-painful, exposed corium + granulation tissue * Tx = block unaffected claw, trim

Question 29

What should be done with axial wall cracks?

Answer 29

* Remove detached horn / granulation tissue + block healthy claw

Question 30

What can cause deep digital sepsis? What should be done?

Answer 30

* Untreated foul in the foot, complicated sole ulcers, untreated white line abscess, puncture wounds * V painful * Tx = amputation / euthanasia / arthrodesis

Question 31

What is a retroarticular abscess? What should be done?

Answer 31

* Abscess above heel bulb, V painful over heel of one digit * Tx = surgery - digital amputation

Question 32

What causes corkscrew claw?

Answer 32

* Hereditary - regular trimming + cull

Question 33

What are risk factors for digital dermatitis?

Answer 33

* 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

Question 34

How is digital dermatitis controlled?

Answer 34

* Identify risk factors + improve conditions * Genetic selection * Early treatment of cases * Footbathing - formalin, copper sulphate, zinc sulphate * Vaccines?

Question 35

How would you treat digital dermatitis?

Answer 35

* Clean + dry lesion * Apply topical antibiotics * NSAIDs

Question 36

What is foul in the foot? Aetiology? What is seen?

Answer 36

* Foot rot - fusobacterium necrophorum * Sweeling above the claws + Strong Odour * V Painful!!

Question 37

How is foul in the foot treated?

Answer 37

* Clean lesion * Remove necrotic tissue * SYSTEMIC Antibiotics * NSAIDs

Question 38

What is interdigital dermatitis?

Answer 38

* Milder infection of interdigital skin? * Dichelobacter nodosus * Can spread across heels = heel horn erosion

Question 39

What is treatment of heel horn erosion?

Answer 39

* Foot trimming * Topical antibiotics