Lameness in cattle

Question 1

Discuss the issue of cattle lameness in the UK?

Answer 1

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

Question 2

What is striking about farmers approach to lameness?

Answer 2

Question 3

What is the cost to a farmer of some of the causes of lameness?

Answer 3

Question 4

What must farmers understand to make them pay attention to their lameness problems?

Answer 4

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

Question 5

How does lameness effect milk yield?

Answer 5

Reduction in Milk Yield across lactation

Earlier in lactation and the more severe the lameness = more milk they loose

Question 6

Lameness is a disease of?

Answer 6

High production

Question 7

How do cows show lameness pain?

Answer 7

• Altered gait
• Hyperalgesia* (A decrease in pain threshold)

Question 8

Welfare implications of lameness?

Answer 8

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)

Question 9

Label the bovine hoof anatomy?

Answer 9

Question 10

Label this?

Answer 10

Question 11

Look at these labels?

Answer 11

Question 12

Describe the pedal bone?

Answer 12

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

Question 13

Describe the sole corium?

Answer 13

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

Question 14

What are the ideal measurements and angles of the bovine hoof?

Answer 14

Question 15

How do bovine limbs bear forces?

Answer 15

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

Question 16

Discuss the bovine toe?

Answer 16

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)

Question 17

Discuss the bovine sole?

Answer 17

The Sole

Overgrowth of the toe leads to thickening of the sole in this regions exacerbating the problem

Question 18

What has happened here?

Answer 18

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

Question 19

Look at these images of toe problems?

Answer 19

Question 21

Where does lameness occur?

Answer 21

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

Question 22

Name some causes of lameness?

Answer 22

• 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

Question 23

What comprises claw horn lesions?

Answer 23

Sole ulceration

White line disease

Digital dermatitis

Question 24

What can be seen here?

Answer 24

Sole Ulcer / Haemorrhage =interchangeable

Question 25

What can be seen here?

Answer 25

White Line Disease * Separation where wall joins sole horn * Dirt can track back = abscess

Question 26

Historical view of how laminitis happens in bovines is incorrect. Pathology is not understood. So if a vet starts talking about laminitis?

Answer 26

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)

Question 27

What is the Proposed Aetiology and Pathogenesis of Claw Horn Lesions?

Answer 27

Question 28

Where do claw horn lesions occur?

Answer 28

Question 29

What causes excess pressure on the dermis?

Answer 29

Question 30

Describe the calving effect?

Answer 30

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

Question 31

Where do collagen fibres run?

Answer 31

Run between P3 and the epidermal laminae

Question 32

How do the digital cushions change after sole ulcers?

Answer 32

Question 33

What is shown in this CT image?

Answer 33

The Digital Cushion CT image

Question 34

What is the digital cushion?

Answer 34

* 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)

Question 35

What is the normal weight bearing series of events?

Answer 35

1. Heel bulbs (particularly the lateral claw) make first contact (“elastic” horn reduced initial shock) 2. Digital cushion and sole and heel dermis act to dissipate concussive forces 3. Elastic tissues expand laterally when compressed transferring energy to the wall (high tensile strength) 4. Majority of weight then transferred to the wall 5. Weight distributed equally between claws (however medial claw slightly smaller) 6. Prolonged exposure to concrete flattens and increases the width of the lateral claw 7. This transfers part of the load to central part of the sole increasing the pressure on the dermis 8. Overgrowth of the lateral claw further increases pressure in this area 9. Prolonged standing on hard surfaces increases the pressure on the dermis

Question 36

The thickness of the digital cushion is linked to what?

Answer 36

The thickness of the digital cushion is linked to body condition score (fat cow = thick cushion and thin cow = thin cushion)

Question 37

What is considered a risk factor for claw horn disease?

Answer 37

* 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

Question 38

How do changes caused by excess pressure on the Dermis appear?

Answer 38

Question 39

How does new bone formation due to excess pressure exacerbate the problem of lameness?

Answer 39

New bone exacerbates the problem by further compressing the germinal epithelium increasing the likelihood of disease

Question 40

Explain the self perpetuating downward cyle of disease?

Answer 40

* 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