Foot lameness in cattle

Question 1

Incidence of lameness in UK dairy farms

Answer 1

55 lameness cases per 100 cows per year

Question 2

Prevalence of lameness among UK dairy cattle

Answer 2

25% of dairy cows are lame at any one time

Question 3

Why are such high lameness levels tolerated on dairy farms?

Answer 3

They are still producing a good quantity of saleable milk

Question 4

What is the estimated economic cost of lameness in dairy cows?

Answer 4

£180 per lameness case

Question 5

What % of lameness in cattle is related to the hoof?

Answer 5

> 90%

Question 6

Distribution of lameness between feet of cattle

Answer 6

Front feet 15% (50:50 lateral and medial claws)

Hind feet 85% (85:15 lateral and medial claws)

Question 7

Bones in the bovine foot

Answer 7

Third phalanx (pedal bone) and distal sesamoid bone (navicular bone)

Question 8

Components of the hoof

Answer 8

Wall, sole, heel, and white line

Question 9

What produces horn in the hoof?

Answer 9

the corium

Question 10

What rate does the hoof horn grow?

Answer 10

5mm/month

Question 11

How long is the dorsal wall of the hoof?

Answer 11

8cm (so takes approx 16mo to grow out)

Question 12

How thick is the sole?

Answer 12

1cm (so takes approx 2mo to grow out)

Question 13

What is the corium?

Answer 13

Horn (hoof) producing tissue, which includes the perioplic, coronary, laminar, and solar corium.

Question 14

What is the white line?

Answer 14

The cemented junction between the wall and the sole

Question 15

What is the digital cushion?

Answer 15

Arrangement of fat and connective tissue that functions to disspate forces when the animal is weight bearing

Question 16

What is the suspensory apparatus of the foot?

Answer 16

Consists of dense collagenous fibres that extend from P3 to epidermal lamellae of the hoof wall, suspending P3 within the hoof capsule.

Function to transform pressure force of weight to a tractional force.

Question 17

Signs of lameness in cattle

Answer 17

Uneven weight bearing or uneven rhythm of strides

Short strides

Arched back

Head nod

Lowered head carriage

Abnormal foot placement

Leg swing wide or narrow of normal

Unsymmetrical body posture

Reduced walking speed or reluctance to move

Not tracking up (hind foot should land in the place left by the fore foot)

Question 18

Mobility scoring of cattle

Answer 18

Best performed on clean, level non-slip concrete and the cows should be ideally seen from the side and then from behind as they walk away from the observer. They should take around 6-10 uninterrupted steps.

0: Good mobility
1: Slightly impaired mobility, affected limb not obvious.
2: Impaired mobility in which the affected limb is identifiable.
3: Severely impaired mobility.

Question 19

How often should dairy cows be mobility scored?

Answer 19

Ideally every 2 weeks

Question 20

Dairy mobility score 0

Answer 20

Walks with even weight bearing and rhythm on all four feet, with a flat back.

Long, fluid strides possible.

• No action needed
• Routine (preventative) foot trimming when/if required
• Record mobility at next
  scoring session.

Question 21

Dairy mobility score 1

Answer 21

Steps uneven (rhythm or weight bearing) or strides shortened; affected limb or limbs not immediately identifiable.

• Could benefit from routine (preventative) foot trimming when/if required
• Further observation
  recommended.

Question 22

Dairy mobility score 2

Answer 22

Uneven weight bearing on
a limb that is immediately
identifiable and/or obviously
shortened strides (usually with an arch to the centre of the back).

• Lame and likely to benefit from treatment
• Foot should be lifted to
  establish the cause of lameness before treatment
• Should be attended to as soon as practically possible.

Question 23

Dairy mobility score 3

Answer 23

Unable to walk as fast as a brisk human pace (cannot keep up with the healthy herd).

Lame leg easy to identify – limping; may barely stand on lame leg(s); back arched when standing and walking.

Very lame.

• This cow is very lame and requires urgent attention, nursing and further professional advice
• Examine as soon as possible
• Cow will benefit from treatment
• Cow should not be made to walk far and kept on a straw yard or at grass
• In the most severe cases, culling may be the only possible solution.

Question 24

Four most common foot lesions in cattle

Answer 24

Sole ulcer
·
White line disease

Digital dermatitis

Interdigital necrobacillosis (Foul of the foot)

Question 25

Claw horn lesions

Answer 25

Sole ulcer

White line lesion

Heel ulcer

Sole haemorrhage

Toe ulcer

Horizontal fissue

Vertical fissure

Axial fissure

Question 26

Infectious causes of foot disease in cattle

Answer 26

Digital dermatitis

Foul, footrot, phlegmon

Heel erosion

Interdigital dermatitis

Question 27

Miscellaneous causes of foot lameness in cattle

Answer 27

Thin sole

Interdigital hyperplasia

Corkscrew claw

Question 28

Sole ulcer (pododermatitis, circumscripta, Rusterholz disease)

Answer 28

Exposed corium at the classic site corresponding to the flexor process of the pedal bone

Question 29

White line lesion (white line separation, white line disease)

Answer 29

Diseased horn affecting the junction between the sole and the wall, including bruising (haemorrhage), separation (fissuring), abscessation and ulceration

Question 30

Heel ulcer

Answer 30

Exposed corium found in the midline of the claw at the junction between the sole and heel. Usually affects medial hind claws

Question 31

Sole haemorrhage (sole bruising)

Answer 31

Bright or deep red discolouration of the sole. Mild bruising can take the form of diffuse pin-prick sized spots or generalised yellowing of the horn.

Question 32

Toe ulcer (toe necrosis, apicalis necrotica)

Answer 32

Diseased horn affecting the white line at the toe, usually with a pungent odour. Often called ‘rotten toes’ by farmers.

Question 33

Horizontal fissure or hardship groove (fissure ungulae, fissure ungulae transversalis)

Answer 33

Linear horn defect parallel to the coronary band affecting the wall horn, causing lameness when the defect extends through the corium

Question 34

Vertical fissure (sandcrack, fissure ungulae longitudalis)

Answer 34

Linear horn defect at 90° to the coronary band affecting the wall horn, causing lameness when the defect extends through to the corium

Question 35

Axial fissure

Answer 35

Linear horn defects affecting the axial wall horn, causing lameness when the defect extends through to the corium

Question 36

Digigtal dermatitis (hairy heel warts, Mortello disease)

Answer 36

A well circumscribed infection of the skin, usually between the heel bulbs or palmar/plantar pastern area.

Lesions generally start as exudative epithelial erosions/ulceration, progressing to granulation, followed by hyperkeratosis and scab formation.

Question 37

Foul, footrot, phlegmon (interdigital phlegmon, interdigital necrobaccilosis)

Answer 37

An acute bacterial infection of the subcutaneous tissue of the interdigital space characterised by symmetrical swelling, separation of the claws and interdigital skin necrosis yielding a pungent odour.

Question 38

Heel erosion (slurry heel)

Answer 38

Heel horn loss, often in the form of variable pits or fissures. Does not commonly affect the corium (and therefore is rarely painful)

Question 39

Interdigital dermatitis (scald)

Answer 39

A superficial epithelial inflammation producing a white exudate with a pungent smell similar to foul.

Experts disagree about the nature of this condition. Many believe it is a mild form of foul or digital dermatitis between the claws

Question 40

Thin sole

Answer 40

A sole that is less than 5mm thick and flexes under firm thumb pressure. Usually associated with excessive wear or over-trimming

Question 41

Interdigital hyperplasia (corn, interdigital fibroma, interdigital growth)

Answer 41

Soft tissue masses between the claws

Question 42

Corkscrew claw

Answer 42

Genetic condition resulting in twisting of the claw capsule. Bony swelling deep to the abaxial coronary band is pathognomic

Question 43

What are claw horn lesions incattle mainly due to?

Answer 43

Failure of the suspensory apparatus

Inadequacy of the digital cushion

These causes changes to the support of the pedal bone allowing movement and exccessive forces to be applied to the horn producing tissue

Question 44

Inadequacy of the digital cushion

Answer 44

Structure of the digital cushion varies with the animal’s age-
in heifers it consists of loose connective tissue that overtime is replaced with fat, for older cows the fat is gradually replaced with collagenous connective tissue which reduces the cushioning capacity.

Therefore, heifers and older cows have less cushioning and increased risk of lameness.

Thin cows have thinner digital cushions than cows with higher body condition score, so these cows have a higher risk of lameness.

Mechanical injury to the corium and digital cushion may also occur in thin soled animals where the protective function of the sole horn is insufficient, particularly on hard walking surfaces.

Question 45

Laminitis theory

Answer 45

Claw horn lesions have been traditionally associated with laminitis.

Acute laminitis uncommonly occurs in cattle and has been associated with acute ruminal acidosis and acute toxaemic conditions.

Claw horn lesions are thought to be associated with subclinical laminitis caused by the same factors, but lameness is not immediately apparent.

Question 46

Causes of laminitis

Answer 46

Associated with disruption of the microcirculation of the blood within the corium leading to the breakdown of dermal-epidermal junction (claw wall and P3).

The main cause of this is thought to be due to rumen acidosis (acute or subacute) releasing various vasoactive substances such as endotoxin, lactate and histamine.

Toxaemic conditions (mastitis/metritis) may contribute and are often found in early lactation cows, such as toxic mastitis and toxic metritis.

Question 47

Pathogenesis of laminitis

Answer 47

Inflammation accompanied by oedema, haemorrhage and necrosis of the corium tissue.

Functional disturbances follow caused by activation of matrix metalloproteinases (MMPs) that degrade the collagen fibre bundles of the suspensory apparatus of P3.

This is exacerbated by epidermal growth and necrosis factors that contribute to alteration of basement membranes and capillary walls.

The vascular effects also interrupt differentiation and proliferation of keratinocytes within the germinal layer of epithelium leading to reduction in keratinisation of horn cells in the stratum spinosum decreasing structural rigidity and strength of claw horn, making it weaker, less resistant to mechanical, chemical and microbial invasion.

Question 48

Hoofase associated failure of the suspensory apparatus

Answer 48

Activation of MMP (matrix metalloproteinases) by “hoofase”, a substance found in the hooves of periparturient animals. Therefore, around parturition there is increased laxity, decreased rigidity, increased load-bearing and deterioration in structural integrity of hooves.

Question 49

Matrix metaaloproteinases (MMPs)

Answer 49

Degrade the collagen fibre bundles of the suspensory apparatus of P3.

Question 50

Failure of suspensory apparatus associated with peripartum hormaonal effects

Answer 50

Weakening of suspensory apparatus is also due to release of oestrogens and relaxin.

These also cause relaxation of pelvic musculature, tendons and ligaments around the time of calving.

Question 51

How does damage to the dermal-epidemral junction and weakening of the suspensory apparatus lead to claw horn lesions?

Answer 51

Predisposes to downward displacement and rotation of P3.

This results in compression of corium and supporting tissues that lie between P3 and the sole this predisposes to the development of haemorrhage and in severe cases sole ulcers.

In some cases, rotation of the apex of P3 is severe enough to cause toe ulcers or sinking of P3 in the rear portion causes heel ulcers.

Shearing forces applied to feet - white line disease.

Question 52

What management factors are associated with claw horn lesions?

Answer 52

Confinement of cows on hard surfaces is the most important predisposing cause.

Excessive standing due to poor housing designs and management procedures where cows are made to stand for long periods are associated with sole problems such as haemorrhage and ulcers.

White line lesions are associated with shear forces on the claws, where mechanical tearing of the compromised white line. This weakening allows material to penetrate causing the disease. Shear forces on feet are due to cows moving in directions that they would not normally go, due to such factors are sharp turns or being pushed backwards in badly managed collecting yards.

Question 53

Other factors associated with claw horn disease

Answer 53

Differential mechanical loads on medial and lateral claws

Longer lateral digits in both forelimbs and hindlimbs.

Heel erosion

Small ‘foot print’ for their size

Biotin (vit B7) deficiency due to altered rumen function (produced by rumen flora)

Question 54

Clinical signs of digital dermatitis

Answer 54

Dermatitis of digital skin that is generally very painful to touch and has a characteristic fetid odour.

Most commonly found on the palmar/plantar interdigital ridge of the foot, especially of hind feet.

Other sites include skin of interdigital cleft, found on hyperplasia, skin around dew claws, the heel sometimes underrunning the sole, and the dorsal aspect of the coronary band.

A white epithelial margin and overlong hair have been described around acute ulcerative DD lesions while more chronic stages associated with dyskeratosis, filamentous or mass-like epithelia proliferations (also called hairy warts).

Question 55

Aetiology of digital dermatitis

Answer 55

Multifactorial caused by spirochetes of Treponema spp.. Other bacterial species such as Fusobacterium spp., Campylobacter spp., Prevotella spp. also isolated from acute DD lesions as secondary invaders.

Question 56

Risk factors for digital dermatitis

Answer 56

Young (low parity) – (Immunity related)

Early lactation – (Immunity related)

Cooler months

Cubicle housing

Higher yields

Poor hygienic conditions (poor slurry management)

Question 57

Classification and scoring system for stages of digital dermatitis

Answer 57

M0: Normal digit skin without signs of DD

M1: Early small circumscribed red to grey epithelial defect less than 2cm

M2: Acute, active ulcerative (bright red) or granulomatous (red-grey) digital skin changes, greater than 2cm dimeter.

M3: Healing stage within 1-2 days after topical therapy, where the acute DD lesion has covered itself with a firm scab like material

M4: Late chronic lesion, may be dyskeratotic (mostly thickened epithelium) or proliferative or both (filamentous, scab like or mass proliferation)

M4.1: Additional stage refers to chronically affected foot that displays M4 stage in addition to M1 stage