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Why do we care about lameness? (3)
animal welfare concerns (pain), decreased production, economic losses (increased culling, decreased preg)
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Sole ulcers mainly contributes to ____________; digital dermatitis mainly contributes to ____________; foot rot mainly contributes to ____________.
milk loss; treatment cost; decreased fertility
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Causes of lameness. (6)
hoof diseases, fractures, hip luxations, joint infections, tendon/ligament disorders, muscle trauma
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What is the primary concept to localizing lameness?
they spend less time on the lame leg (down on sound, short-strided)
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What is very suggestive of dorsal hip luxation?
greater trochanter in line with tuber coxae and tuber ischii- greater trochanter should be ventral, forming a triangle
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What is very suggestive of ventral hip luxation?
greater trochanter disappears- rectal palpation to try and feel femoral head in obturator foramen
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How does a cow stand if lame on the medial claw(s)?
- unilateral- leg further under body
- bilateral- crossed legs
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How does a cow stand if lame on the lateral claw(s)?
leg(s) placed more laterally than normal (put weight on medial claw)
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What are the 3 most common pathologies of the stifle joint?
patellar luxation, collateral ligament rupture, CCL ligament rupture
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You can flex the stifle and extend the hock simultaneously...what's wrong?
peroneus tertius rupture
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You can flex the hock with the stifle straight/extended....what's wrong?
gastroc rupture
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What is the 90% rule?
- 90% of bovine lameness is below the fetlock.
- 90% is in the rear leg.
- 90% is in the lateral claw.
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What foot diseases may make the cow non-weightbearing lame, but are usually negative with hoof testers? Why?
foot rot, digital dermatitis (hairy heel wart), interdigital hyperplasia (corn-usually not lame unless huge); soft tissues of interdigital space--> hurts to bear weight, but hard parts of hoof are unaffected
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What are the 2 agents most commonly associated with foot rot?
Dichelobacter nodosus, Fusobacterium necrophorum
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Describe the pathogenesis of foot rot?
maceration from water/urine/feces--> skin gets soft/friable--> mechanical lesions develop in skin--> anaerobic environment for bacteria
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What are clinical signs of foot rot? (6)
pain/lameness, foul odor, swelling, erythemia of soft tissues, exudate, necrosis
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What is the treatment of foot rot? (3)
Pen G, local disinfection (oxytet, erythromycin), animals in clean/dry environment
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Describe prevention of foot rot. (3)
separate infected animals, clean/dry environment, copper or zinc sulfate footbaths
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What is the etiology of hairy heel wart?
spirochete- Treponema
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What are the 2 presentations for hairy heel wart?
erosive/reactive condition; proliferative wart-like lesions
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What is the treatment for hairy heel wart?
topical oxytetracycline
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What are prevention measures for hairy heel wart? (3)
dry environment, segregate infected cows, proper hygiene
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What causes corns?
result of chronic irritation in interdigital region due to buildup of slurry dried on hooves
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What are preventative measures for corns?
prevent buildup of slurry from drying on feet
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Describe the pathogenesis of laminitis.
disturbance of microvascular circulation of the corium--> degeneration and inflammatory changes at the dermal-epidermal junction
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What are sequelae of laminitis? (4)
impaired horn production, sole ulcers, white line disease, claw deformation
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What are potential causes of laminitis? (4)
carb overload and lactic acidosis, excess protein, endotoxemia, mechanical factors
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Where do Rusterholz ulcers most commonly occur?
plantar process of distal phalanx- point of maximal pressure; lateral hind claw
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Describe the pathogenesis of sole ulcers.
[soft diseases soles] laminitis, heel erosions, most environment--> flat soles, long toes--> pressure concentration at plantar process of P3--> ischemic necrosis of corium--> granulation tissue
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What is the treatment for sole ulcers? (2)
pare out lesion, block on opposite toe
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What is the pathogenesis of white line disease?
wet conditions/claw deformities/laminitis soften white line further--> penetration of debris--> abscess formation and disintegration of white line--> ulceration
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How do you treat white line disease?
remove dead tissue, provide drainage, balance claws; +/- check for involvement of deeper structures, claw amputation, facilitated ankylosis
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Describe prevention of white line disease.
proper hygiene, claw trimming, foot baths
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