Musculoskeletal 1 Flashcards
What are the two most common problems on a dairy farm?
Lameness
Mastitis
Why is lameness important to the dairy industry?
Decreased milk production
Decreased reproduction
—15x more likely to have increased days open
— 8x more likely to be culled for repro failure
What clues should you look for when examining a cow for lameness?
Head bob
Limping or reluctance to bear weight
Hunched up back
Joints flexing unequally, or one more stiff than the other
Tracking up: rear feet should land almost in the foot prints left by the front feet
Where is lameness most commonly localized?
90% in the foot
Of that, 85% in the rear foot
Of that, 85% in lateral claw
Where is hoof horn generated?
From dermis (corium)
What is the white line?
Dermal papillae of laminar corium that generates horn
=> softest horn, abaxial heel is softest
What is the rate of growth of the hoof wall?
5mm/month or 1/4 inch
About 1 year seen on a whole hoof
What is the response of the corium to weight bearing?
Increased rate of horn production
Imbalance in weight bearing and overloading to the outside claw —> long toes and high heel —> increase risk to trauma to corium and higher risk for ulcer
Common conditions of the foot?
Interdigital phlegmon “foot rot”
Digital dermatitis
Heel horn erosion
Bacteria involved in foot rot?
Fusobacterium necrophorum
Porphyromonas levii
Prevotella intermedia
** anaerobic environment and tissue destruction with proteases and lukotoxins
What is the pathogenesis of foot rot?
Clot formation/local ischemia
— endotoxins and platelet aggregation
Protection from phagocytosis
Fusobacterium produces leukotoxin
P. Levii decreased optimizing antibodies
How does foot rot impact the feeding period?
Decrease ADG of 0.05kg/day
14 additional days to finish
What are the primary bacteria causing foot rot in small ruminants?
Dichelobacter nodosus (primary)
F necrophorum
What is the treatment for foot rot?
Debridement (bring air back to anaerobic bacteria)
Antibiotics
- ceftiofur
- oxytetracycline
- florfenicol (nuflor)
- gamithromycin
- tilmucosin (mycotil)
A market steer presents with foot rot 7 days before his last show. Which of the following treatment options is best?
A oxytet
B florfenicol
C Enrofloxacin
D ceftiofur
D ceftiofur
Withdraw time is less than 7 days
Infectous foot rot in sheep is best treated by?
A enrofloxacin
B procaine pen G
C gamithromycin
D tilmucosin
C gamithromycin works the best against anaerobes
PPG also would work against anaerobies but not as good
Digital dermatitis is AKA ?
Hairy heel warts Strawberry foot Verrucous dermatitis Digital warts Interdigital papillomatosis
EDx of digital dermatitis?
Treponema spp (spirochetes)
What environmental conditions predispose to digital dermatitis?
Confinement
Excess manure
Increased standing due to poor stalls or over crowding
Treatment for digital dermatitis?
Oxytet (topical or systemic)
Footbaths
- copper sulfate >5% solution
- formalin
What are common causes of heel horn erosion?
Poor environmental hygiene
Bacterial degradation of heel horn
What causes loss of heel horn?
Claw instability
Weight sift
Ulcer develop
What causes thin soles?
Rate of growth < rate of wear
Eg wet rough concrete or increased standing time
Excess trimming
During early lactation, hoof growth rate is decreased
What is the sequelae to thin soles?
Damage to sole corium
- toe ulcers or sole ulcers
White line dz
- less mature horn exposed
- more susceptible to foreign material penetration
Where are the most common locations for solar ulcers to occur in ruminants?
Lateral claw of hind foot
Medial claw of fore foot
What is the most common indication of a sole ulcer, besides lameness
Hemorrhage
What is white line disease?
Inflammation, ischemia of laminar corium
Often caused by shearing and compressive forces of P3
Increased rate and decrease quality horn growth —> fissure cracks
What occurs in subclinical laminitis?
Claw horn integrity compromised
Suspensory apparatus compromised
- collagen connecting P3 to lamellae
- digital cushion —> cruciate ligaments affected at attachments
Why does the toe tip up in laminitis ?
A pushed away from P3 by blood
B increased goth of dorsal hoof
C extensor tendon pull
D increased heel growth
D increased heel growth
Common causes of laminitis in cattle?
Dairy
- mastitis and metritis
- lactation ration
Beef
-feedlot
Rumen acidosis
Treatment of laminitis?
Acute — NSAIDS or euthanasia
Chronic — hoof trim and diet
What is the pathogenesis of laminitis?
Vasoactive compounds result in decreased blood flow —> ischemia, edema, pressure, and epidermal damage
Laminar corium damaged — P3 sinks and compresses sole corium
Generalized damage — increased rate and decreased quality of horn production
What role do cytokines play in laminitis?
Acute grain overload increases IL-1 in hoof laminae
MMP present in normal hoof for remodeling but may be out of control in laminitis (activated by cytokines, ROS, and NO)
—> can be increased at calving
How much laying time should a cow have per day??
10-12 hours
What is the ideal stall surface material?
Sand
Composite
Rubber filled mattresses?
DRY!
T/F: cows prefer to walk and stand of soft surfaces
True
Rubber mats in walkways
What type of foot baths are available to treat hoof disease?
Copper sulfate (5-10% solution)
Zinc sulfate
Formalin (2-5% solution) — formalin is cheap but less safe
What is often the only sign of solar trauma?
Discolouration of solar horn overlying point of entry
