Functional anatomy of the cow's foot

Question 1

Aetiological theories - sole ulcer

Answer 1

• Loss of laminar suspension around calving
• Loss of fat pad
• Long standing times
• Laminitis and drop/rotated PIII
• Poor foot angle
• Sole over-growth
• Bone exostoses
• Inflammation in a closed compartment
• Soft claws and heel erosion

Question 2

Sequealae - sole ulcer

Answer 2

Possible answers include:

• Synovitis
• Tenosynovitis
• Heel abscess
• Rupture of DDF insertion on PIII
• Osteitis
• Chronic infection with DD
• Scarring and likely recurrence
• New bone formation on PIII
• Fat necrosis/steatitis
• Deep digital sepsis, leading to claw amputation or culling

Question 3

White line - aetiological theories

Answer 3

Very little good evidence published:
• Biotin deficiency (Hedges et al 2001)
• Soft claws during high rainfall (Nz cows)
• Loss of fat pad
• Thin soles (Nz cows/Wisconsin zero-grazed sand)
• Over trimming
• Rough, stoney tracks
• Bruising from long standing times (Bell et al 2006)
• Sharp turns on concrete
• Pushing and shoving e.g. backing gate over-use

Question 4

Sequelae - white line

Answer 4

• Wall ulcers
• Under-run sole or side wall
• Unlikely to produce deep digital sepsis
• Scarring and recurrence

Question 5

Digital dermatitis - aetiological theories

Answer 5

• Three families of Treponeme, gaining entry through hair follicles

Question 6

Sequelae - digital dermatitis

Answer 6

• Cross infection
• Chronic infection in deep dermal tissues, which is unresponsive to most antimicrobial treatments
• Interdigital hyperplasia

Question 7

Toe necrosis - aetiological theories

Answer 7

• Treponemes invading from coronary band in interdigital space
• Treponemes gaining entry through over-trimmed toes

Question 8

Sequelae - toe necrosis

Answer 8

• Chronic infection and severe under-run
• Heel-first gait
• Stretched tendons
• Cross-infections

Question 9

Aetiological theories - foul

Answer 9

• Fusobacterium necrophorum biotypes A, B and AB (ubiquitous)
• Ingress through macerated skin and/or wounds in the interdigital space

Question 10

Sequelae - foot foul

Answer 10

• Interdigital hyperplasia
• Axial wall and sole under-run (like sheep with scald/foot rot)
• Superfoul – term usually reserved for peracute cases but epidemics can evolve to involved mixed bacterial infection, leading to cases of SF
• Superfoul cases are usually shot on farm