Lameness in cattle Flashcards
Discuss the issue of cattle lameness in the UK?
In top 3 problems facing UK dairy industry
- Welfare
- Health
- Cost
22 –70 cases / 100 cows / year
An important but less common disease in suckler cows Poor recording = hard to estimate
1 in 3 lame at any one time is not good enough
What is striking about farmers approach to lameness?
What is the cost to a farmer of some of the causes of lameness?
What must farmers understand to make them pay attention to their lameness problems?
Cost of Lameness
It’s the other costs which are the main contributors to financial issues. Should communicate the financial implications of the loss of production
How does lameness effect milk yield?
Reduction in Milk Yield across lactation
Earlier in lactation and the more severe the lameness = more milk they loose
Lameness is a disease of?
High production
How do cows show lameness pain?
- Altered gait
- Hyperalgesia* (A decrease in pain threshold)
Welfare implications of lameness?
Many consider lameness the most significant welfare issue currently affecting UK dairy cows
- Number affected
- 25% of population
- ~500,000 animals in the UK at one time
- Level of discomfort
- Duration of episodes
- 27 ± 19d* (around a month)
Label the bovine hoof anatomy?
Label this?
Look at these labels?
Describe the pedal bone?
Pedal bone
- Centrally within hoof
- Strong connective tissue attachment to the dorsal wall
- Flexor tendon attached to caudal edge, with navicular bone between tendon and P2
Describe the sole corium?
Sole corium
- Fills space between pedal bone and hoof capsule
- Blood vessels, nerves and other support structures
- Digital cushion –pad of fat and elastic tissue. Dissipates force and transfers load to the wall during foot strike and limb loading.
- Stratum germinativum –produces sole horn
What are the ideal measurements and angles of the bovine hoof?
How do bovine limbs bear forces?
Normal weight bearing
- Wall, white line, heels and abaxial parts of the sole
During Walking
- Force generated by hind limbs (fore limbs act as “posts”)
- Up to 80% of load borne by lateral claw (the metatarsal bone is longer is that digit) particularly during heel strike and limb loading
Standing
weight more evenly distributed between claws
60% fore feet
40% hind feet
Discuss the bovine toe?
The Toe
- Wall is produced more rapidly at the toe and the heel can be undermined by slurry heel in winter.
- If stood in wet ground too. Front of toe curves up and shifts all the weight.
- This leads to further overgrowth of toe (none weight bearing) and weight shifted further back (toe angle <45 o)
Discuss the bovine sole?
The Sole
Overgrowth of the toe leads to thickening of the sole in this regions exacerbating the problem
What has happened here?
Disparity of claw size (lateral claw of hind foot tends to overgrow-due to the way the cow swings weight out)
- weight bearing on lateral claw (longer metatarsal) -> increase irritation and sole overgrowth -> increase pressure and pain in lateral claw –> leg swung out –> increase weight on medial claw –> reduced wear on lateral claw
- Overgrowth at toe forces hocks together –> decrease weight bearing on lateral claw
- Udder distension (particularly in early lactation) –> Leg swung out to reduce contact with udder
Look at these images of toe problems?
Where does lameness occur?
The vast majority of bovine lameness occurs in the lateral claw of the hind feet. Most in the hind feet due to the weight bearing movements (its like a rear drive car). Hind feet are easiest to trim too
Name some causes of lameness?
- Sole ulceration
- White line disease
- Digital dermatitis
- Local sole bruising
- Foul in the foot
- Interdigital hyperplasia
- Foreign body penetration
- Heel horn erosion
- Heel abscess
In order of occurence
What comprises claw horn lesions?
Sole ulceration
White line disease
Digital dermatitis
What can be seen here?
Sole Ulcer / Haemorrhage =interchangeable
What can be seen here?
White Line Disease
- Separation where wall joins sole horn
- Dirt can track back = abscess
Historical view of how laminitis happens in bovines is incorrect. Pathology is not understood. So if a vet starts talking about laminitis?
Clarify what they mean by laminitis and if they explain via mediators they are wrong.. Basically and you gottatrust John
Naming of this syndrome currently remains un-clear could call it:
- Sub-clinical laminitis (SCL)
- Claw horn disruption (CHD)
What is the Proposed Aetiology and Pathogenesis of Claw Horn Lesions?
Where do claw horn lesions occur?
What causes excess pressure on the dermis?
Describe the calving effect?
The Suspensory Apparatus
- Collagen fibres run from P3 and anchored in the dermal lamellae and hence to the claw capsule
- Suspend the pedal bone with in the hoof capsule by transferring and distributing the load
- Hence the suspensory apparatus determines the degree of compression of the sole dermis
- The “quality” of the collagen fibres and connective tissues is critical, any deterioration will cause sinkageand / or rotation of the pedal bone
- At parturition –tendons and ligaments relax (this happens all over the body). Hence the bone drops in the foot
Where do collagen fibres run?
Run between P3 and the epidermal laminae
How do the digital cushions change after sole ulcers?
What is shown in this CT image?
The Digital Cushion CT image
What is the digital cushion?
- Three cylindrical parallel oriented bodies
- Capsule of connective tissue filled with fat
- High in mono unsaturated fatty acid
- Fully develop during the second lactation (fat content increases with age)
What is the normal weight bearing series of events?
- Heel bulbs (particularly the lateral claw) make first contact (“elastic” horn reduced initial shock)
- Digital cushion and sole and heel dermis act to dissipate concussive forces
- Elastic tissues expand laterally when compressed transferring energy to the wall (high tensile strength)
- Majority of weight then transferred to the wall
- Weight distributed equally between claws (however medial claw slightly smaller)
- Prolonged exposure to concrete flattens and increases the width of the lateral claw
- This transfers part of the load to central part of the sole increasing the pressure on the dermis
- Overgrowth of the lateral claw further increases pressure in this area
- Prolonged standing on hard surfaces increases the pressure on the dermis
The thickness of the digital cushion is linked to what?
The thickness of the digital cushion is linked to body condition score (fat cow = thick cushion and thin cow = thin cushion)
What is considered a risk factor for claw horn disease?
- Thinning of the digital cushion, via loss of body condition (particularly weight loss to peak yield in high yielding cows) is now considered a risk factor for claw horn disease We don’t know where in the cycle this starts.
- Thought those who loose weight in early lactation = lame
- Rapid weight loss is thought to be the lameness risk factor
How do changes caused by excess pressure on the Dermis appear?
How does new bone formation due to excess pressure exacerbate the problem of lameness?
New bone exacerbates the problem by further compressing the germinal epithelium increasing the likelihood of disease
Explain the self perpetuating downward cyle of disease?
- Disease is predominantly seen in older cows, and animals which have had previous lameness events
- Once disease becomes chronic cows are more difficult to treat and less likely to recover
- It often takes time for the benefits of herd intervention programmes to become apparent
