Ruminant Lameness Flashcards
Why do we care about lameness in ruminants?
1) 20-50% of dairy cattle have some detectable gait abnormality
2) Second most common clinical disease
3) Third most common reason for culing
4) 20-30% of sheep operations have foot rot
What is the estimated cost of clinical lameness in dairy cattle
$500 per case
costs
1) treatment
2) reduced milk production
3) Reduced fertility (increased days open, increased days to firsts service, increased number of services/conception)
4) Culling
5) Death loss
What are the animal welfare concerns with lameness in ruminatns
lameness interferes with an animal’s ability to exhibit natural behaviors by altering lying time, social itneraction, ovarian acitivty, estrus intensity, and possibly rumination behavior
*producers and vets have a certain obligation to produce an ehthical product and minimize harm
an consumer and retailers have vested interest in animal welfare
90% of ruminant lameness is due to
problems in the foot
(two digits of the limb in artiodactyls)
therefore it means that these issues are in one or both digits of the limb and distal to fetlock
What does foot mean in ruminants
anything distal to the fetlock, not just structures within the hoof capsule and P3
What causes foot issues in ruminants
50% infectious
-foot rot, hairy heel warts (digital dermatitis), interdigital dermatitis
50% non-infectious: originating from hoof conformation issues
In ruminants, is the keratin of the sole or the keratin of the hoofwalls softer
keratin of the sole
-animals need to be walking on the hoofwall
What is the white line in the ruminants hoof
the junction between the vertical hoof walls with the sole
highly vascular and innervated tissue that provides nutrition to the hoof
dense matrix of connective tissue -connects the basement membrane of the dermal epidermal junction to the periosteal surface of P3 and thus suspends P3 from the innerwall of the hoofcapsule
corium
What connects the basement membrane of the dermal epidermal junction to the periosteal surface of P3
Corium
-thus suspens P3 from the innerwall of the hoofcapsule
What attaches bony P3 to the hoof capsule
Laminae
in the wall and tightly attached to lateral and cranial portions of P3 and interdigitate with insensitive lamina in the hoof capsule
sensitive laminae
Why do ruminants have a smaller laminar region of the digit compared to horses
because they have less surface area of contact per unit of supported weight
Conditions that disrupt the corium will result in
significant pain! and non-weight bearing
In ruminants,
The fetlock is __________________ while the pastern joint is ______________
fetlock is proximal to dewclaws
pastern is roughly halfway between coronary band and dewclaw
In ruminants, what might penetrating wounds and deep ulcers or abscess of the heel cause
secondary infection of 1) navicular bone and bursa
2)coffin joint
3) digital flexor tendon
helps fix the bony column in vertical formation and pulls the tip of P3 ventrally transfering the weight forward
deep digital flexor tendon
a complex arrangement of fat deposits between P3 and solar corium (lamina)
cushion and distribute weight trasnferred to the sole
-thickest at heel
-helps with vascular and lymphatic return
Digital cushion
In ruminants, the digital cushion is thickest at the
heel
In ruminants, what is normal growth rate of hoof
5-6 mm per month
influenced by Nutrition, lactation, gestation,cycle, season, substrate/footing
Positive influences on hoof growth
copper
zinc
iron
biotin
What diet in ruminants leads to ruminal acidosis and laminitis (coritis)
excessive carbohydrate in the diet
In ruminants, what hoofs bear more weight
Front feet: medial claws
Hind feet: lateral claws
In the front limb, hoof lesions are more often to occur in the
medial claws - animal bears more weight
In the high limbs, hoof lesions more often occur in the
lateral claw- animal bears more weight
How can you identify a foot-sore ruminant from a distance
1) Arched back
2) Ears are back
3) Restless, shifting weight, tail flicking constantly
4) head position is variable
What is seen with footpain
when touching it with a jet of water or a stick, the animal will rapidly flex the joints of the upper limb to bring the foot up off the ground
How do you notice ruminants with upper limb pain
hesistant to to flex those joint and move those bones and soft tissues.
they will hold the joints in neutral, slightly bent posture and move those joints minimally as they walk. Short anterior phase to the side
How do you distinguish between upper and lower limb pain in ruminants
Lower limb: animal will rapidly flex the limb upwards when touching it
Lower limb: joints held in neutral and will move the joints minimally as they walk
What is seen with medial claw pain
more often the forelimb
it may adduct the limb in order to place more weight on the sound lateral claw
What is seen with lateral claw pain
more often the hindlimb
may abduct the limb in order to place more weight on the sound medial claw; the limb may be held slightly outward rotated position as well
Is abduction seen with medial or lateral claw pain?
lateral claw pain
Is adduction seen with medial or lateral claw pain
medial claw pain
what is a great tool for detecting generalized soft tissue swelling in the ruminant foot **
Dewclaws - compare with the contralateral limb
dewclaws are anchored in soft tissue of the digit, if it swells, the dewclaws will spread apart.
How might you differentials differ with bilateral dewclaw swelling vs unilateral *
Bilateral - more likely interdigital disease (eg bovine foot rot)
Unilateral - more likely septic synovial structure
why are the dewclaws in ruminants a helpful method in assessung swelling
they are loosely anchored in the soft tissues, they are spread further apart in the swollen foot versus the non-swollen foot.
Bovine lameness scoring systems
1-5
1= normal, level back, no lameness
5= significant lameness
modification with feedlot animals as you cant get as close to them
you have a cow with a base-wide hindlimb stance. In what limb and digit does this cow have pain?
hindlimbs, bilateral (lateral claw) disease likely
but get more information on movement
How do you examine the cow’s foot
Restraint is key
1) Tilt tables- common in dairies, puts far less back/low back strain on the individual
2) Ropes- limb that is to be worked on is secured with ropes to the side bars of the chute/stocks
3) Standing chute or stocks
How do you examine the foot of ruminants
1) Wash surface of foot
2) If sole remains dirty, use hoof knife to remove superficial layer of horn
3) Look at the white line as it is a common area for lesions
4) Hoof testers - sole, heel, and hoofwall
non-painful one first, re-apply to see if it repeatable and increase confidence of results
5) Palpate each digit - flex and extend
6) Examine the sole for any dark colored defects
When using hooftesters in cattle, what limb do you want to do first
non-painful claw and limb first
get the cow used to the pressure of the hoof tester so that it increases the likelihood that they are demonstrating a response to discomfort rather than a response to a new stimulus
What do dark-colored defects on cow’s sole indicate
sole absceses- any defects should be carefully pared out with a hoof knife to determine if there is any underlying exudate
How often should ruminant hoofs be trimmed
Dairy: recommended 2 times a year
Beef/Small Ruminants: vaires by operation, terrain, and distance traveled
When hoof trimming ruminants, how much should you trim
Trim to a length of 7.5-8cm
add 3mm for each 75kg over 750kg
maintain adequate sole thickness of ~5mm at the toe tip
excessively long toes shifts weight bearing in the
palmar/plantar direction
puts it over the softer heel horn, can lead to bruising or pressure necrosis of the heel horn
also increased strain on flexor tendons
Sole ulcer/Rusterholz ulcer
an ulcer that is caused by pressure necrosis of the heel horn by overgrown claws sifting the weight bearing in the palmar/plantar direction
ucler could allow bacteria to colonize deeper structures like the DDFT sheath, navicular bursa, coffin joint, etc.
What are the result of overgrown claws in ruminants
1) Weight bearing shifted in palmar/ plantar direction
2) Sole ulcer (could allow bacteria to colonize deeper structures of DDFT sheath, navicular bursa, coffin joint)
3) Increased strain on the flexor tendons
What may result of the entire thickness of the corium undergoes pressure necrosis
it may allow surface bacteria to colonize the digit deep to corium
corrective trimming
the well trimmed foot has a center of weight bearing that is moved more toward the center of the digit where the sole horn is much thicker and there is additional weight bearing support provided by the hard vertical walls of the center of the hoof
What are the 4 most. common causes of foot lameness in ruminants
1) Digital dermatitis (hairy heel warts)
2) Laminitis
3) Sole abscesses
4) Interdigital necrobacillosis (foot rot)
The most common cause of lameness in dairy cattle *
Digital dermatitis
What are other names for digital dermatitis
hairy heel wart
strawberry goot
verricois dermatitis
digital warts
interdigital papillomatosis
What causes digital dermatitis in cattle
Contagious polybacterial disease
-Treponema spp. involved
-Bacteria invade epidermis
T/F: Treponema alone causes digital dermatitis
False- Tremonema is thought to be the cause but several studies investigated potential role of D. nodusus, F necrophorum, bacteroides, porphyromonas spp
With digital dermatitis, what does the lesion look like
Starts as red, eroded granular lesion, exudative, hairs at periphery matted
Progresses to look like a big wart with raised conical projections of epithelium (blackened keratin)
typically in the palmar/plantar aspect of the interdigital skin and/or skin just above the heel bulb
lesion progresses over time, takes 130-150 days
