Foot lameness in cattle Flashcards
Incidence of lameness in UK dairy farms
55 lameness cases per 100 cows per year
Prevalence of lameness among UK dairy cattle
25% of dairy cows are lame at any one time
Why are such high lameness levels tolerated on dairy farms?
They are still producing a good quantity of saleable milk
What is the estimated economic cost of lameness in dairy cows?
£180 per lameness case
What % of lameness in cattle is related to the hoof?
> 90%
Distribution of lameness between feet of cattle
Front feet 15% (50:50 lateral and medial claws)
Hind feet 85% (85:15 lateral and medial claws)
Bones in the bovine foot
Third phalanx (pedal bone) and distal sesamoid bone (navicular bone)
Components of the hoof
Wall, sole, heel, and white line
What produces horn in the hoof?
the corium
What rate does the hoof horn grow?
5mm/month
How long is the dorsal wall of the hoof?
8cm (so takes approx 16mo to grow out)
How thick is the sole?
1cm (so takes approx 2mo to grow out)
What is the corium?
Horn (hoof) producing tissue, which includes the perioplic, coronary, laminar, and solar corium.
What is the white line?
The cemented junction between the wall and the sole
What is the digital cushion?
Arrangement of fat and connective tissue that functions to disspate forces when the animal is weight bearing
What is the suspensory apparatus of the foot?
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.
Signs of lameness in cattle
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)
Mobility scoring of cattle
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.
How often should dairy cows be mobility scored?
Ideally every 2 weeks
Dairy mobility score 0
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.
Dairy mobility score 1
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.
Dairy mobility score 2
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.
Dairy mobility score 3
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.
Four most common foot lesions in cattle
Sole ulcer
·
White line disease
Digital dermatitis
Interdigital necrobacillosis (Foul of the foot)
Claw horn lesions
Sole ulcer
White line lesion
Heel ulcer
Sole haemorrhage
Toe ulcer
Horizontal fissue
Vertical fissure
Axial fissure
Infectious causes of foot disease in cattle
Digital dermatitis
Foul, footrot, phlegmon
Heel erosion
Interdigital dermatitis
Miscellaneous causes of foot lameness in cattle
Thin sole
Interdigital hyperplasia
Corkscrew claw
Sole ulcer (pododermatitis, circumscripta, Rusterholz disease)
Exposed corium at the classic site corresponding to the flexor process of the pedal bone
White line lesion (white line separation, white line disease)
Diseased horn affecting the junction between the sole and the wall, including bruising (haemorrhage), separation (fissuring), abscessation and ulceration
Heel ulcer
Exposed corium found in the midline of the claw at the junction between the sole and heel. Usually affects medial hind claws
Sole haemorrhage (sole bruising)
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.
Toe ulcer (toe necrosis, apicalis necrotica)
Diseased horn affecting the white line at the toe, usually with a pungent odour. Often called ‘rotten toes’ by farmers.
Horizontal fissure or hardship groove (fissure ungulae, fissure ungulae transversalis)
Linear horn defect parallel to the coronary band affecting the wall horn, causing lameness when the defect extends through the corium
Vertical fissure (sandcrack, fissure ungulae longitudalis)
Linear horn defect at 90° to the coronary band affecting the wall horn, causing lameness when the defect extends through to the corium
Axial fissure
Linear horn defects affecting the axial wall horn, causing lameness when the defect extends through to the corium
Digigtal dermatitis (hairy heel warts, Mortello disease)
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.
Foul, footrot, phlegmon (interdigital phlegmon, interdigital necrobaccilosis)
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.
Heel erosion (slurry heel)
Heel horn loss, often in the form of variable pits or fissures. Does not commonly affect the corium (and therefore is rarely painful)
Interdigital dermatitis (scald)
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
Thin sole
A sole that is less than 5mm thick and flexes under firm thumb pressure. Usually associated with excessive wear or over-trimming
Interdigital hyperplasia (corn, interdigital fibroma, interdigital growth)
Soft tissue masses between the claws
Corkscrew claw
Genetic condition resulting in twisting of the claw capsule. Bony swelling deep to the abaxial coronary band is pathognomic
What are claw horn lesions incattle mainly due to?
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
Inadequacy of the digital cushion
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.
Laminitis theory
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.
Causes of laminitis
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.
Pathogenesis of laminitis
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.
Hoofase associated failure of the suspensory apparatus
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.
Matrix metaaloproteinases (MMPs)
Degrade the collagen fibre bundles of the suspensory apparatus of P3.
Failure of suspensory apparatus associated with peripartum hormaonal effects
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.
How does damage to the dermal-epidemral junction and weakening of the suspensory apparatus lead to claw horn lesions?
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.
What management factors are associated with claw horn lesions?
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.
Other factors associated with claw horn disease
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)
Clinical signs of digital dermatitis
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).
Aetiology of digital dermatitis
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.
Risk factors for digital dermatitis
Young (low parity) – (Immunity related)
Early lactation – (Immunity related)
Cooler months
Cubicle housing
Higher yields
Poor hygienic conditions (poor slurry management)
Classification and scoring system for stages of digital dermatitis
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
