Non-infectious causes of lameness Flashcards
What are the 3 most common causes of lameness?
- sole ulceration
- white line disease
- digital dermatitis
What are sole ulceration and white line disease cases also known as?
Claw horn lesions
What kind of lesions are these photos examples of?
Sole ulcer / haemorrhage
What is the old hypothesis behind the cause of claw horn lesions?
High oligofructuose overload in the diet
Can acidosis cause sole haemorrhages?
No - it has been proven
What is now know to cause claw horn disease?
Pressure lesion of soft tissue below P3 - causes alteration to the production of the sole which leads to lesion formation
What causes excess pressure on the dermis of the sole?
Environmental factors
- hard standing/walking surfaces (often used because easy to clean)
- standing/lying times (if doesn’t lie down for long enough in the day and stands too much >12hours)
- track surfaces/maintenance (if pushed along quickly and walk onto rocks will cause injury)
Calving effect
- relaxin produced during claving will cause tendons to relax in foot (suspensory apparatus of P3 are loose and gives it a chance to sink and rotate)
Changes to the normal structures in the hoof
- digital cushion thickness (associated to BCS so don’t want cows to be too thin)
- Milk yield and energy balance
- Previous lameness - means they are at higher risk of developing further lameness because will have greater new bone development on P3 due to inflammatory process and will compress dermis
- also means they are less likely to recover from lameness (euthanasia?)
When are digital cushions fully developed by?
Fully develop during the second lactation (fat content increases with age) - their BCS is important to get them to develop properly
Describe the normal weight bearing in the foot during locomotion
- 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
What 2 factors affect normal weight bearing?
- Overgrowth of the lateral claw further increases pressure in the dermis
- Prolonged standing on hard surfaces increases the pressure on the dermis
How should you treat claw horn lesions?
- treatment trim
- block foot
- NSAIDs
Most important factor - treating early!!
How can you make sure lameness is picked up early?
Regular mobility scoring
How does the administration of NSAIDs at calving affect lameness?
Animals in 1st lactation that given NSAIDS were at lower risk of developing lameness in their subsequent lactation
Give NSAIDS
How can you prevent the development of sole lesions?
- Promote lying (cubicle comfort - deep bedding)
- Regular trimming (pre-calving, peak lactation, dry off)
- Make sure BCS is maintained in the transition period (manage diet)
- Limit standing times (splitting cows into more groups so they are not all at the same time in collecting yards for long periods of time)
- Surface (rubber matting where cows stand for a long time)
- Identify and treat animals early to limit impacts of disease (scoring every 2 weeks)
How much lunge zone do we need in cubicles for cows to get up comfortably?
90cm
How can you reduce the risk of sole lesions in post calving period?
Heifers
* Cubicle training during rearing
* Provide at least one month in cubicles before they calve
* Expose to concrete before they calve if they will be on concrete post-calving
* Allows the foot to adapt to the post calving environment
Fresh cow group
* Provide “best” cubicles at a low stocking rate or very clean straw yard for 4-6 weeks after calving
* Reduces pressure on feet during risk period
* Reduces stress during the post calving period
NSAIDs at calving
What are risk factors for white line disease?
- Poor underfoot conditions/ track conditions
- Turning sharply, shearing forces
- Periparturient increase in the movement of the pedal bone
- Loss of fat from the digital cushion and new bone formation on P3
How can we prevent white line disease?
- improve cow tracks
- repair damaged yards
- let cows walk at own pace
- no sharp turns, steep sections or bottle necks
- free of sharp grit
- grooving concrete to reduce slipping
What can be added to the diet to reduce incidence WLD?
Biotin 20mg/cow/day
