Production Animal Lameness + Ruminant Foot Structure

Lameness

• clinical sign not disease - adjustment of gait to relieve pain

• physiological distress → decreased production

• nutritional and hormonal impacts

• consider at individual and herd level

  • herd level → management/husbandry improvements

• 88% feer

• other sites - dislocated hips, spinal issues or nerves

Clinically relevant anatomical key words

Ruminant foot anatomy → lameness causes

• often solved by foot trimmers rather than vets

1. Laminae → laminitis

2. White line (junction between horn of wall and sole of foot)

   • When foreign body invades white line → white line disease

3. Hoof wall, pedal bone, sole horn

4. Corium (dermis)

   • Sits underneath pedal bone

   • Sits above horn of sole and dorsal wall of foot

5. Digital cushion

   • Fat pad → acts as shock absorber as pedal bone bounces on top of corium

   • Sits under pedal bone process

     • Skinny cow/Poor horn growth → depleted fat in digital cushion → hook process of P3 presses against the corium → sole ulcer

Most frequent ruminant foot lesions [4]

1. sole ulcer

2. white line disease

3. digital dermatitis

   • strawberry raw lesion at palmar/plantar aspect at cleft underneath dewclaws

4. Fouling foot (foul)

   • penetration injury of digital space

   • bacteria grows in hoof soft tissues

   • swelling + infection of hoof

   • pressure builds in enclosed space → swelling inside hoof capsule seen at coronary band

3+ 4} infections → can appear together

1+2} claw horn traumatic disruption lesions, requires debridement

Sheep lameness

• Infectious causes more common than noninfectious

• Scald-footrot complex biggest problem (65%)

  1. Scald

  2. Shelly hoof → white line disease

  3. Toe abscess

  4. Toe granuloma

  5. CODD → contagious ovine digital dermatitis

  6. Footrot

Infectious vs traumatic

• Traumatic (claw horn disruption lesions)

  • Sole ulcer → most often affects outer hind claw

  • White line disease

  • Sole bruising

• Infectious

  • Digital dermatitis - most sheep lesions

• Both often involved simultaneously

Lameness clinical signs

• Arched back

• Swelling on non weight bearing foot

• Dull

• Struggling to stand

Lameness consequences

• Reduced ability to stand and move freely

• Reduced ability to feed

  • reduced appetite (pain/immobility)

  • unable to reach food

  • competition from other cows

• Results in:

  • reduced milk yield

  • reduced BCS/ weight loss → reduced digital cushion

• Reduced fertility

  • reduced detection → not mounting cows in heat

  • will not stand for bull

  • low BCS → struggle to get into calf, hormone imbalances → irregular cycles → high cull rate

Direct costs of lameness

• Treatment fees

• Labour time

• Decreased milk yield:

  • Wasted due to drug withdrawal time

  • Reduced milk yield

Indirect costs of lameness

• Reduced future fertility

• Increased culling

Mobility scoring (AHDB)

• 0, 1, 2, 3

• 0 not lame, 3 non weight bearing

• Can be used to distinguish animals needing treatment

• Can be used as prevalence indicator at herd level

Score 0

• Walk with even weight bearing and rhythm on all 4 feet

• Flat back

• Long fluid strides possible

• Scoring timing/frequency: 100 day in milk check and dry off trim may be good routine for sound cows

Score 1

• Uneven steps (rhythm or weight bearing) or strides shortened

• Slight arch to back?

• Affected limb(s) not immediately IDable

• Remedial attention → routine trimming and further observation

Score 2

• Uneven weight bearing on limb that is immediately IDable

• Obviously shortened strides may be seen (usually with arch to centre of back)

• Lame → feet should be lifted and examined ASAP

Score 3

• Unable to walk as fast as brisk human pace → cannot keep up with healthy herd

• Signs of score 2

• Lame → urgent attention and treatment, should be kept on straw yard on pasture

• Culling if severe to relieve pain → best catch lameness earlier before it reaches 3

Prevalence

• Mobility scoring

• Number of lame cows on farm AT GIVEN TIME TESTED

• 36/100 cows were score 2 or 3 when tested → prevalence is 36% during time tested

Incidence

• Lameness records (multiple scores/recordings) → serial records

• Number of NEW cases that have occurred in given period of time

  • does not take into account when one cow has multiple incidences

• 36 cases recorded in 100 cows in 3 years → incidence is 12 cases per 100 cows per year

• 200 new cases recorded in 100 cows in a year → incidence is 200 cases per 100 cows per year (cows had more than 1 new case in that period)

Husbandry Factors Affecting Lameness 1

White Line

Husbandry Factors Affecting Lameness 2

Digital Dermatitis

Husbandry Factors Affecting Lameness 3

Solar Ulcer

Key lameness prevention

• Mobility scoring, keep records

• Rapid treatment of clinical cases

• Footbath schedule

  • Morning → formalin

    • Ensure footbath is long enough to be covered in a couple of strides

    • All feet dunked in

  • Afternoon → CuSO4

• Routine trimming

Summary info

• Huge welfare/economic impact

• Large number of husbandry/farming factors involved in lameness

• Apply herd level approach to:

  • Understand pathogenesis

  • Spot control points

  • Use evidence based interventions

Farm factors for cow lameness

• Lack of routine trimming

• Prolonged standing

• Bad biosecurity

• Slurry management

• Biotin supplementation for horn quality

• Bedding material

• Cubicle comfort

• Stocking density

• Feed space

Surface issues

• Slippery/uneven concrete

• Wet conditions

• Rough tracks

Cow factors

• Low BCS

• Distal phalanx descent

• Toe length and foot angle overgrowth

• Horn quality

• Chronic pedal bone changes + fat pad scarring

• Matrix metalloproteinase + relaxin released during calving period → slackens suspensory ligament and DFTs

Ruminant Claw

Cloven - hoof → Split = interdigital cleft 

• Inside split of interdigital cleft = axial surface btw 2 claws

• Abaxial - outside (lateral surfaces) = remaining rounded surface of the claw

• 2 digits on each foot

Regions

Sole → slightly concave region on palmar/plantar aspect of each digit 

Heel (Bulb) → slightly convex region at heel of sole

Wall 

• Abaxial aspect - convex + merges with bulb 

• Axial aspect - junction with bulb has groove = axial cleft 

Dermis = Corum of wall

Similar to horse - arranged in laminae

Interdigitates with the epidermal horn - produced by papillon coronary region 

• dermal layer of the coronary band

• contains papillae = make coronary and solar hoof wall

  • supply nutrients to hoof wall and sole

    • lamellae - suspend and attach P3

Horn on the sole & bulb - also produced by papillae

Hypodermis in bulb - forms pad of fibrous elastic tissue = digital cushion

Dewclaws - present in most ruminants - do not make contact with ground 

Consist of wall and bulb but no practical importance

Ovine interdigital pouch

• Found in fore and hindlimbs of both sexes

• Pouches are tubular invaginations of the skin 

• Walls of pouch contain sebaceous & serous glands

• Discharge waxy secretion which spreads down onto hooves 

• Serves as trail-marker

Horn Growth

Horn of hoof grows at rate of 5mm per month 

Growth should = wear in cattle move freely 

Intensively kept cattle → Growth > Wear ⇒ foot trimming required to maintain optimal shape and angle 

Horn overgrowth: coffin joint is gradually overextended and deep flexor tendon tensed 

• Greater weight placed over caudal part of the hoof and can cause pain and lameness