LAM 3 Midterm 1 Flashcards
What feedlot changes lead to lameness?
high energy diet + substrate changes - lameness
Where does 90% of dairy cow lameness occur?
rear limb lateral claw
What is the most common lesion associated with sheep lameness?
interdigital space lesions
How will cattle stand if they have lameness in their lateral digit?
base wide stance
How will cattle stand when they have medial claw lameness?
base narrow or limbs are crossed
What are the 3 synovial structures in the ruminant foot
Distan Inter tarsal Joint
Navicular Bursa
Flexor tendon sheath
What is graveling?
deep foot infection has to migrate to release the pressure at which tends to occur at the soft tissue planes
What is the role of the Periolic coria?
it is a moisture barrier to underlying coria
What spirochete is responsible for 50-70% of bovine lameness in the U.S?
Treponema
they live deep in the epidermis and create inflammation
What is considered the dirtiest foot zone + why
zone 0 because spray cleaners don’t reach between the claws
What are clinical signs of mild irritation of the interdigital skin (zone 0)?
small, red ulcers
mild swelling + pain
undermine heel: seperate perioplic corium from the underlying horn of the bulb
What do the cs related to mild irritation of the interdigital skin lead to?
overgrowth of the heel resulting in increased heel weight-bearing + concussive injury = rusterholz ulcer
What is the proper term that is commonly referred to as “foot rot”?
interdigital dermatitis
What bacteria are commonly involved in interdigital dermatitis?
Fuscobacterium +/- dichelobacter or porphoromonas
Define the pathology found in interdigital dermatitis
skin break caused by deep necrosis
What is super foot rot?
necrotizing, penicillin resistant necrobacillosis of the foot
What is the name of the disease condition associate with 80% of all lameness in sheep?
interdigital dermatitis (foot rot)
What are some cs + findings of interdigital dermatitis in sheep?
often malodorous
walk on their carpi (if forelimb disease)
Fuscobacterium + Dichelobacter
What are the 3 phases of digital dermatitis
heel ulcers
strawberry foot rot
hairy heel warts or “mortellaro”
Describe the “heel ulcer” phase of digital dermatitis
circumscribed erosion/ulcer on border of plantar commissure, or at skin horn jxn, near the declaws (zone 10) or interdigital space
Describe the strawberry foot rot phase of digital dermatitis
ulcer fills in with granulation tissue
Describe the hairy heel wart phase of digital dermatitis
papillomatous growth
As chronicity increases, granulation tissue toughens up + frong like growths can occur
What microbe is responsible for causing digital dermatitis
Tremonema spp.
spirochete in the skin leads to irritation then erythema and inflammation + skin breaks resulting in ulcers
What happens when tremonema enters a herd?
epizootics of foot problems and after the adult cows develop partial immunity + mild lesions but if new heifers are introduced they still get severe disease
Describe the progression of Contagious ovine digital dermatitis when it spreads through a herd
it starts at the coronary band and leads to underrunning and sloughing of hooves
Treponema related, spreads via new additions to flocks
What is interdigital hyperplasia + what are the lay terms for it
chronic irritation leads to hyperplastic tissue growth which may become ulcerated
usually secondary to another lesion
lay terms: fibroma or corn
What is interdigital hyperplasia an indicator of?
that there was a breakdown of the cruciate ligaments that are responsible for keeping the digits together
Describe the general treatment plan for soft tissue lesions
- clean foot w/ disinfectant scrubs
- Debride/resect necrotic or proliferative tissue
(be conservative around dorsal commissure) - Sterilize open wounds:
-foot baths, topical disinfectants, +/- topical antibiotics (extralabel use)
4.) Deep infections- systemic anbx
5.) consider bandages/ wires
6.) corrective trimming of contributory hoof lesions
7.) decreased the 4 M’s
What topical anbx would you consider for treponema?
tetracycline
linomycin
spectinomycin
If a patient has a deep infection caused by a soft tissue lesion, what drugs would you consider?
penicillins or sulfas for most
if “super foot rot” oxytetracycline
consider tilmicosin for digital dermatitis
What preventative measures can be taken to prevent ST lesions
adequate draining or lime absorbants
manure scrapings
straw bedding
even atraumatic surfaces
limit puddles +snoes
decrease udder hosing
foot baths regularly
regularly trim hooves
What are the 3 main areas that excessive horn growth tends to occur?
toe, abaxial wall, heel
What sequelae can occur when excessive toe growth is present
straining of the flexor tendons
movement of weight to the heel, splayed toes
What sequelae can occur when there is excessive growth at the abaxial wall ?
can strain the cruciate ligament and splays the claws
What sequelae can occur when there is excessive growth at the heel?
weight is moved to the heel which increases risk of concussive injury
a wide heel traps material in ID space
What can be seen when there is laminitis of the coria that makes up the wall? (coronary coria)
the wall will develop horizontal cracks aka “hardship grooves”
exacerbated by long toes
lever action can put pressure on coria
you can determine how long ago the insult occurred based on how far down the hoof wall it is
Describe the lesion that develops secondary to interrupted growth at the sole or heel
“Double Sole” : Anerobic pocket for bacteria that develops when the horn stops growing then restarts growing
What does white line seperation secondary to interrupted growth allow for?
abscess development
What does interrupted growth at the heel cause?
seperation from the skin known as an “underrun heel” that allows bacterial invasion
What changes does laminitis aka pododermatitis aseptica et diffusa cause to the horn when abnormal horn growth has occurred?
Horn becomes soft, bloody and mealy
it allows for bacterial invasion
no longer protects the soft tissue
When is the most common time we see hardship grooves in cattle?
1-3 months post partum
What are some genetically induced horn lesions in ruminants
screw claw
poor hoof confirmation or quality
What is laminitis induced compartment syndrome
edema + hemorrhage between hoof + bone
T or false: Horn lesions may promote ST lesions lesions and ST lesions may affect the adjacent corium
True! Bad horn lesions can do this
What do most horn problems result from?
abnormal production
this is secondary to diseases of of the corium/ laminae = laminitis
Problems of the ____ are most viable but problems on the ___ are most important
Wall; sole
Where do abscesses like to commonly occur in beef cows?
along the white line
near the toe (zone 1)
Where do abscesses like to occur in dairy cows?
along the white line
the lateral wall near the caudal sole
Why is ventral drainage of abscesses so important?
no ventral drainage means that infections will travel dorsad and reach vital structures
What is the pathogenesis that leads to a rusterholz ulcer?
weak or absent horn (laminitis) + concussive force (overgrowth) lead to injury + increased udder weight
severe injury will destroy the underlying corium and lead to proliferation of granulation tissue
Where do small ruminants tend to get horn overgrowth
abaxial wall grows long + curls under in small ruminants
Where do cows tend to have horn overgrowth?
the heel, abaxial wall and the toe
When performing corrective shoeing, what are important steps to ensure the foot is being reshaped to correctly bear weight?
we want a flat sole to spread weight evenly
remove extra toe, abaxial wall and heel
ensure there is good balance
avoid damaging the periople
dig out onfected tracks + cracks
remove double soles
trim back granulation tissue
place block on the sound claw if the other claw is very sore
check for infection of deeper structures
What can producers do to help prevent hoof lesions?
keep cows healthy - slow adaption to enviornments + diets, good hygiene, good bedding + stalls
exercise without too much standing around
softer substrates
regular hoof trims (2x a yr), foot baths, genetics
T or F donkies + horses have the same pain thresh hold
False, a dull donkey = a thrashing horse! Donkies are extremely stoic.
What causes wind-up pain in horses?
severe colitis, laminitis
What are some examples of patients that aren’t good NSAID candadites
pregnant, hypovolemic, hx of kidney disease,
What NSAIDs impact both the COX-1 and COX-2 pathways?
ketoprofen, meloxicam. flunixin meglumate (banamine), phenybutasone (bute),
What NSAID only targets the COX-2 pathway?
Firoxib
What are we taking away from the patient when we block productive prostaglandin synthesis?
pregnancy maintenance, liver, kidney, GI mucosa, blood clotting
What are indications of NSAIDs ?
pain, inflammation, pyrexia, anti-endotoxemia
Contraindications for NSAID administration
received a full dose less than 12 hours ago
renal compromise (elevated creatinine)
hepatic impairement
NSAID toxicity: right dorsal colitis
gastric ulcers
pregnancy/lactating
neonates
clotting disorder, thrombocytopenia