Exam 1 - Food Animal Musculoskeletal Diseases Flashcards
cattle put more weight on the _____ claw in the front, & on the _____ claw in the rear
medial
lateral
T/F: lameness is a major cause of culling in dairy cattle
true
85-90% of lameness we see in the ____, with 85-90% in the ______ limbs, & 80-90% affecting the ______ claw
foot
rear
lateral
what is a lameness grade of I?
animal is normal
what is a lameness grade of II?
there is a slight abnormality & an uneven gait
what is a lameness grade of III?
slight but obvious lameness present
what is a lameness grade of IV?
obvious lameness & the animal has difficulty turning
what is a lameness grade of V?
animal is non-weight bearing
where should you start your physical exam on a lame patient?
restrain the animal & start with the foot, & clean it well
use hoof testers, percussion, hyper-extend/flex the digits, look for obvious sole lesions, and palpate for any heat/swelling
what is the rate of growth of the hoof wall?
1/2cm a month at the toe & 1cm a month at the heel
what is the wall of the hoof?
cornified epidermis - a lot of keratin at the sole mainly
what makes up the sole in a cow?
softer keratin that is thicker toward the heel
T/F: the front feet of a cow are larger together than the rear feet & are more flat in comparison
true
what is the general shape of the rear feet in a cow?
oblong & concave
why use hoof testers on the foot?
differentiate pain from fighting physical restraint
where are bruises & ulcers most commonly located in the sole of the foot?
caudal third of the sole
why is it important to know that the tendon sheaths don’t communicate with one another after the bifurcation proximal to the fetlock joint on the plantar/palmar aspect?
in animals with tenosynovitis, you don’t want to contaminate the other side
when amputating a digit from a cow, why is it important to remove the bone at a 45 degree angle at the distal 1/3 of P1?
the dorsal interdigital cruciate ligaments need to stay intact - this angle helps avoid damaging them
what is concerning about infection present at the axial interdigital skin?
it is the closet point to the distal interphalangeal joint, & it can easily extend up into it
what is the attachment site of the deep digital flexor tendon? why is it important?
attaches to P3 at the junction of the heel & sole - important to consider with sole ulcers
if using a wooden block as treatment in a lame animal, where should the block be placed?
on the unaffected toe - helps raise the affected toe off of the ground
what is an example of how longevity of an animal with a toe amputation is dependent on use & the animal’s environment
lateral claw removal on the rear limb of a breeding bull - animal won’t last long
front lateral claw removal may last years on a bull used for natural collection & not natural service
T/F: the use of flunixin in lactating dairy cows is appropriate as it has a 4-day slaughter withdrawal time
false - cannot use in lactating dairy cows!!!
T/F: phenylbutazone can be used in dairy cattle under 20 months of age
true - need to have a valid VCPR to do this
correct conformation of the bovine hoof includes the fact that the soles of the rear claws are relatively _____, while the soles of the front claws are relatively ________
concave
flat
what is footrot in cows?
infection of the interdigital skin & deeper structures
what agents cause footrot in cows?
fusobacterium necrophorum (leukotoxin & endotoxin) & porphyromonus levii (spreads lesion via collagenolytic enzymes) - both require means of entrance because they can’t penetrate intact skin
both are gram negative obligate anaerobes normally found in bovine gi tract
what is the pathogenesis of footrot in cows?
there is compromise of the interdigital skin
12-24 hours, diphtheritic membrane appears marking the start of necrosis
48 hours - lesion is seen in entire interdigital space
name the disease
foot rot
what clinical signs would you expect this animal to present with?
typically affects one limb with a mild to non-weight bearing lameness
will see necrotic tissues at the edges of the lesion & swelling/redness above the coronary band because deeper subcutaneous structures are commonly invaded
how do you treat footrot in cattle?
oxytetracycline is the favorite choice - want a systemic antimicrobial
what is the most severe sequela to footrot in cattle?
it invades the coffin joint
how can footrot in cattle be prevented?
improve the animal’s environment - reduce chances of interdigital trauma/constant fecal contamination/contact
f. necrophorum bactrin - 2 doses, 3-4 weeks apart followed by yearly booster
aureomycin feed additive
what is bovine contagious interdigital dermatitis?
acute to chronic inflammation of the interdigital skin that does NOT extend into deeper tissues - results in heel horn erosion & undermining of the heel bulbs
what is the agent that causes bovine contagious interdigital dermatitis?
dichelobacter nodosus
what clinical signs do you expect this patient to present with if it has this lesion?
mild lameness (paddling - walking on eggshells) & superficial erosions/undermind heel bulbs, & melting of the horn, no necrosis - bovine contagious interdigital dermatitis
what are some things that can predispose a cow to developing bovine contagious interdigital dermatitis?
continuously wet/unhygienic conditions & sequelae to laminitis
how do you treat bovine contagious interdigital dermatitis?
put the animal on dry ground/clean environment
topical treatments & trim off loose tissue with frequent foot care/trimming
how is bovine contagious interdigital dermatitis prevented?
improved management of cattle
what is another name for papillomatous digital dermatitis?
hairy heel wart
what clinical signs would you expect this patient to present with if it has this lesion?
severe lameness/weight shifting - small lesion is very painful to the touch
expect to see it above the heel bulbs around the coronary band (sometimes on the dorsal aspect) in the interdigital space with fronds at the periphery (wash cloth appearance) - hyperplasia of epidermis
how does a cow get this lesion?
associated with spirochete (treponema), increased moisture in the environment, & potentially a zinc deficiency
how can you differentiate between foot rot, hairy heel warts, & bovine contagious interdigital dermatitis?
hairy heel warts are not necrotizing like footrot & hairy heel warts are more proliferative than bovine contagious interdigital dermatitis
how are hairy heel warts prevented?
management of the moisture/filth!!!! spray/vaccine available
how are hairy heel warts treated?
cleaning & oxytetracycline under a bandage!!!!! frequent foot baths to inactivate disease causing agents
what is contagious footrot in sheep?
interdigital dermatitis with extension into adjacent epidermal tissue underlying the hard horn
how is contagious footrot in sheep transmitted?
carrier sheep in a warm, moist environment
what agents are associated with causing contagious footrot in sheep?
dichelobacter nodosus, f. necrophorum, & actinomyces pyogenes
what is the pathogenesis of contagious footrot in sheep?
the agents love anaerobic environments within deep fissures/cracks in the hoof - travel through wet, inflamed interdigital skin causing necrosis
extends laterally/caudally through layers of underlying soft & hard horn - separation of axial bulb horn from the under-running bulb, sole, axial, & abaxial walls - causes deep pockets of necrosis
if you’re concerned about contagious footrot in a sheep, what clinical signs would you expect the animal to have?
severe lameness with 50-75% of the flock affected
how is contagious footrot in sheep treated?
radical hoof trimming!!!!!!!
systemic antibiotics (PPG or oxytetracycline), foot baths with zinc sulfate
cull severe cases & get them into a dry environment
how is contagious footrot in sheep prevented/controlled?
hoof trimming 2-4 times a year & footvax/volar (vaccines)
what is this lesion?
contagious footrot in sheep
what antibiotics would you use for treating this?
PPG or oxytetracycline
what is the lesion seen in the photo?
subsolar abscess
what causes a subsolar abscess?
anything that allows entrance to spaces under the horn
puncture wounds, concrete/grinder burns, white line disease, inferior hoof quality, & bruises
what are the possible sequelae of a subsolar abscess?
joint, tendon, or ligament involvement
what are the clinical signs seen with the lesion in the picture?
pain & altered stance
no swelling!!!!
how do you treat subsolar abscesses?
systemic abx, curettage all undermined horn, wooden block on good claw
what is tenosynovitis?
usually an extension of digital disease into the deep digital flexor tendons
secondary to - footrot, white line disease (allows an opening that starts an infection that can spread to the joints/tendon sheaths), & trauma
what clinical signs do you expect to see in a cow with tenosynovitis?
severe lameness & swelling/drainage of synovial fluid from the tendon sheath (usually pronounced & extends up the limb to above the hock sometimes)
unilateral distended sheath
if you’re concerned about tenosynovitis, why is ultrasound helpful?
can help differentiate between infection in the sheath vs the surrounding tissue
how is tenosynovitis treated?
adequate drainage & flush - treat like an abscess, but remember it is essentially an open joint!!! must be covered with a sterile bandage after & changed daily for the first 5 days
what are some sequelae of tenosynovitis?
tendon separation, fibrosis/adhesions, & chronic lameness - very time consuming expensive condition!!!
what is primary septic arthritis/physitis?
penetration into the joint - trauma
what is secondary septic arthritis/physitis?
extension into the joint from adjacent infection
what is tertiary septic arthritis/physitis?
systemic or hematogenous spread (navel, polyarthritis, endocarditis)
what joint in cows is most commonly affected by septic arthritis?
coffin joint
what clinical signs are associated with septic arthritis/physitis?
pain, heat, significant swelling, marked lameness, & potentially systemic signs
how is septic arthritis/physitis diagnosed?
physical exam, synovial fluid aspirate, inflammatory leukogram, culture, & ultrasound
what is the treatment for septic arthritis/physitis?
joint lavage early (1-3 days) into the course of disease
arthrotomy - sometimes the only way to address a chronically septic joint (signs greater than 2-3 days) due to fibrin build up in the joint
what is the prognosis of septic arthritis/physitis?
poor - joint infections are difficult to treat without permanent damage
what infectious diseases of the digit cause moderate to severe lameness with swelling above the coronary band?
footrot
contagious footrot in sheep
tenosynovitis
septic arthritis/physitis
osteomyelitis
what infectious diseases of the digit cause moderate to severe lameness WITHOUT swelling above the coronary band?
papillomatous digital dermatitis
subsolar abscess
what non-infectious diseases of the digit cause moderate to severe lameness with swelling above the coronary band?
potentially - P1 fracture
potentially - white line disease
what non-infectious diseases of the digit cause moderate to severe lameness WITHOUT swelling above the coronary band?
sole ulcer!!!!!!
sand crack & thimble crack - depends
laminitis
white line disease
how do you treat a fracture of P3 in a cow?
wooden block on good claw
how do you treat a fracture of P2/P3 in a cow?
cast foot to just above the fetlock
how do you treat a fracture of P1 in a cow?
cast to enclose the foot & include carpus/tarsus
what is the etiology of laminitis?
believed to be an ischemic event in capillaries in laminae - endotoxin thought to play a role
animals on high concentrate, low long stem roughage diets
what is the pathogenesis of laminitis?
hyperemia - hemorrhage - thrombosis - vasculitis - hypoxia - leads to edema, necrosis, followed by separation, & rotation
quality of horn produced is affected for life - inferior horn will crack, bruise, erode more easily
separation of white line, axial grooves leads to packing with dirt, manure, infection, & deeper spread
what are the clinical signs associated with acute laminitis in cows?
weight shifting, pain, heat felt, walking stiffly (on eggshells), increased HR/RR
what are the clinical signs associated with chronic laminitis in cows?
chronic pain from secondary conditions occurring in the foot
how do you treat acute laminitis in cows?
correct the cause
laxatives (magnesium oxide), NSAIDS for endotoxemia, antihistamines if early, & soft bedding
how do you treat chronic laminitis in cows?
foot care & regular trimming
what is the etiology of sole ulcers?
big one - long heels & long toes
overgrown toes, high concentrate diets (low grade laminitis), & cubicles are too small
what are the clinical signs associated with sole ulcers?
painful lesion at the junction of the heel & the sole - may have erupted tissue
!!! attachment site of DDFT !!!
why is the location of this lesion important to consider?
sole ulcer - attachment site of DDFT
what is the treatment for sole ulcers?
rads to determine extent of involvement/duration
foot trim & pare out all undermined horn, trim out granulation tissue, block healthy claw
may need to amputate/arthrodesis depending on severity
prognosis is guarded depending on extent of structures involved
what animals are more commonly affected by sand cracks?
heavier bulls/cows - rodeo bulls
85% in the front lateral claw
what lesion is shown here? what is the etiology?
sand crack (vertical fissure)
laminitis (inferior horn quality), stress lines, or nutritional problem
what is the major clinical sign of sand cracks?
crack in the horn that may extend to the coronary band
how are sand cracks treated?
trimming - shorten & roll toe to quicken break over & put less pressure on the toe
keep hooves soft, curettage/drainage/keep clean, wooden block on healthy claw
how long will this take to heal?
6-8 months
toe will take 1 year
if you have a cow present with a grade 3/5 lameness & no swelling above the coronary band, what differentials are you considering?
subsolar abscess
sole ulcer
P3 or P2 fracture
vertical or horizontal wall fissure
white line disease
what is thimble claw? what are some potential causes?
horizontal fissures - laminitis/inferior horn can predispose
what clinical signs are associated with thimble claw?
usually all 4 feet have stress lines - probably a vascular event
what is the treatment for thimble claw?
pare off the unattached horn
what is the prognosis of thimble claw?
good unless there are deeper tissues involved
what is white line disease?
separation to suppuration of white line - most often abaxial wall (weight bearing area across toes also)
seen on front medial claw & rear lateral claw
what lesion is this?
white line disease
what lesion is this?
thimble claw - horizontal fissure
what is the etiology of white line disease?
sequelae of laminitis, thin walls, wet conditions, & overgrown hoof
what are the clinical signs of white line disease?
uncomplicated - pain due to movement along the junction of the wall & sole, dark areas at the white line due to packing of fecal material/dirt into separation
severe - lateral penetration, navicular bursitis & drainage above the coronary band & DIP joint infection
what is the treatment for white line disease?
remove affected sole/wall, self cleaning (make a groove to allow manure and/or other material to escape
systemic abx if deeper structures are involved, wooden block on unaffected toe
careful with toe lesions that extend to P3 - can cause osteomyelitis
what are interdigital fibromas?
corns - hyperplasia & fibrosis of interdigital skin, animals may or may not be lame, but typically are benign
what may predispose an animal to developing corns?
overfeeding, wet/filthy conditions, & irritation
what are the clinical signs of corns?
seen most commonly on the front feet of bulls & rear feet of cows
what is the treatment for corns?
benign neglect or remove them
what is corkscrew claw?
rotation of the lateral hoof wall toward the axial plane - results in the malalignment of P2 & P3
seen on the lateral claws of rear limb & medial claws of the front, may be evident at 1-3 years of age
how do you tell if corkscrew claw was inherited in an affected animal?
heritable - see it in all 4 limbs
chronic problem/regrowth - only one claw
what are some sequela of corkscrew claw?
DJD, ligament damage, lifetime of hoof trimming/correction, & sole ulcers
don’t breed these animals - heritable condition
what are some factors that may lead to stifle injuries?
slip & fall (hypocalcemia)
fighting
breeding injuries
what are the clinical signs you would expect to see in a cow with a stifle injury?
animal avoids flexing the stifle, holds the hock & stifle in a fixed position, weight is placed mainly on toes, legs camped under body to take weight off of affected limb, periarticular/joint swelling, quadriceps/gluteal muscle atrophy, & potentially see lameness in foot
what clinical signs are associated with a CCL rupture in a cow?
effusion into the medial femorotibial joint
how is a CCL rupture treated in cows?
salvage, stall rest, collect semen/embryos, or surgery
what do you think is wrong with this bull?
CCL rupture - effusion seen
what do you think is wrong with this bull?
stifle injury
what is this?
corn
what condition does this animal have?
corkscrew claw
