Unit 2 - Lameness in Cattle Flashcards
T/F: Lameness is one of the most costly clinical diseases of dairy cattle.
True
What digits of the bovine foot supports the most weight?
Digits 3 and 4
A.
Heel
B.
Sole
C.
White Line
D.
Abaxial wall
E.
Axial wall
F.
Interdigital space
The white line is the junction between the ____ and the ____ of the foot.
Wall; sole
What is the laminar corium also known as?
The suspensory apparatus
What does the laminar corium do?
It suspends P3 within the claw capsule and produces horn of the white line
The laminar corium interdigitates with what?
The lamelae of the wall
What claw lesions typically cause lameness?
Sole ulcers, white line disease abscessation, traumatic lesions of the sole, and foreign bodies
Where do sole ulcers always occur and what do they result from?
At the heel-sole junction resulting from the pressure into the sole
What is white line disease?
When an abscess occurs within the white line
What traumatic lesions of the sole can result in lameness?
Holes in the sole that reach the corium caused by sharp objects on floors
Foreign bodies that make contact with the solar or perioplic corium
Breaks in the sole caused by excessive wear
What is a sole abscess?
Any and all of the following can abscess - sole ulcers, white line disease, traumatic lesions of the sole, and foreign bodies
The point is - a sole abscess can occur as a sequelae of any of these things
T/F: An abscess is a diagnosis.
False - an abscess is a condition that occurs secondary to a sole ulcer, white line disease, and traumatic lesions of the sole - it is not a diagnosis
90% of lameness is in the _____, 90% of that involves the ______ _____, of that, nearly 90% involves the ______ _____.
Foot; rear feet; outside claw
What are the two main components of claw disorders?
Mechanical and metabolic
What mechanical causes can result in sole ulcers and white line disease?
Overgrowth, overloading, and excess weight bearing
What metabolic causes can result in sole ulcers and white line disease?
Rumen acidosis, enzyme induced, and hormonal
How can metabolic processes result in sole ulcers and white line disease?
The suspensory apparatus becomes weakened and there is sinking and rotation of P3
What part of the claw will have the most overgrowth?
The more weight bearing part of the claw - which just so happens to be the outer claw
What enzymes can result in sole ulcers and white line disease?
metalloproteases
What are the risk factors for the metabolic component of claw disorders?
Carbohydrate feeding - rumen acidosis
Peri-partum period - activation of MMP and hormonal changes
Excessive time standing
MMP-9 is associated with ______ induced laminitis.
acidosis
Pro MMP-2 causes what?
Physiological/pathological remodeling of connecctive tissue
When is MMP-2 activated?
During the peri-partum period
What peripartum hormonal effects can result in lameness?
Weakness by hormonal changes at or around calving (estrogen and relaxin)
How do cows present with acute laminitis?
Camped under posture - arched back, tender-footed, and extreme reluctance to walk
How does chronic laminitis affect the horn?
It accelerates horn growth resulting in overgrowth of the toe and walls and permanent disfiguration of the hoof
What occurs during phase 1 of laminitis?
Release of vasoactive substances, impaired blood flow to the corium, with degeneration and weakening of the suspensory apparatus
What occurs during phase 2 of laminitis?
Sinking or the downward displacement of P3 and compression-related injury of the corium and digital cushion underneath
What occurs during phase 3 of laminitis?
Characterized claw horn lesions - hemorrhages, WLD, and sole ulcers
When is the onset of phase 3 of laminitis?
8-9 weeks after the onset of phase 1
Describe the suspensory apparatus of the bovine claw.
P3 is fixed in position by a series of collagen fiber bundles that run from the zone of insertion on the surface of the bone to the basement membranes
What is laminitis in regards to the suspensory apparatus?
The loosening, weakening, and/or elongation of the collagen fiber bundles leads to sinking of P3
What forms the horn of the white line?
the laminar coreum
How does standing on hard flooring surfaces affect the suspensory apparatus?
It causes stretching, elongation, hemorrhage, and inflammation
What does standing on hard flooring surfaces result in?
Hemorrhages in the white line and poorer quality white line horn
Prevalence of sole ulcers and white line disease was significantly associated with the thickness of what?
The digital cushion
Thickness of the digital cushion is highly correlated with what?
Body condition scores
Following the sinkage of P3 what happens to the digital cushion?
The fat content is substantially reduced and it is replaced by collagenous connective tissue and less fat
Bottom line: ______ cows get lame.
thin
For most claw lesions, what is the appropriate treatment?
Corrective trimming and a foot block to the healthy claw to relieve weight bearing on the injured claw
What is the purpose of corrective trimming of the hoof?
Removal of all loose horn around the lesion
How do hoof wounds heal?
By second intention - the wound is left open and allowed to close by epithelization and contraction
There are ___ phases to hoof wound healing.
4
What is the first phase of hoof wound healing?
Hemorrhage and blood clot formation
What is the second phase of hoof wound healing?
Inflammatory phase where WBC phagocytize bacteria and cellular debris at the site of injury
What is the third phase of hoof wound healing?
Proliferative phase - characterized by angiogenesis, fibroplasia, granulation tissue formation, epithelialization, and tissue contraction
What is the fourth phase of wound healing?
Remodeling phase - the formation of a scar and lesion contraction
Epithelialization begins at _____ _______ and continues _______.
Wound edges; centripetally
What is the objective in wound healing?
The rapid unimpended re-epithelialization of the lesion
The clinical indicator of an interference with wound healing is the formation of what?
exuberant granulation tissue
What is the multimodal approach to pain management in lameness cases?
- Use a IV regional or ring block for corrective trimming and tx
- Avoid damaging healthy corium tissues during corrective trimming
- Use foot block on healthy claw
- Avoid topical therapies
- Administer analgesics, NSAIDs, sedative-analgesics
- Provide comfortably housing and thoughtful management
What is wind-up pain?
An exaggerated pain reaction in response to a lesser stimulus.
How does the ‘wind-up’ pain phenomenon occur?
Persistent pain and inflammation results in the ‘winding up’ of the sensory neurons in the spinal cord and brain
What type of pain is meloxicam indicated for in cattle?
Nocioceptive or aching types of pain It is for extralabel use
What type of pain is gabapentin indicated for in cattle?
Treatment of chronic neuropathic pain or wind-up pain
______ treatment of the corium should be avoided.
Caustic
What are the infectious disorders of the foot and foot skin in cattle?
Digital dermatitis and foot rot
T/F: Digital dermatitis is the most common infectious disease affecting housed dairy cattle world-wide
True
What is digital dermatitis?
A poly microbial disease involving treponemes and other anaerobes
How does digital dermatitis appear clinically?
Lesions appear as a raw, red, oval ulcer on the back of the heel
The lesions are often raised with a wart-like appearance
Hair-like projections of epithelium may extend upward from the surface with chronic lesions
T/F: The abundance of treponemes remains consistent as a digital dermatitis lesion progresses.
False - it increases
How long does it take for a lesion due to digital dermatitis to progress?
From normal skin to a mature lesion it is 130-140 days
What is the standard protocol for treatment and control of digital dermatitis?
Topical treatment and footbaths
T/F: Although topical treatment and footbaths reduce digital dermatitis lesion pain, recurrence rates are high.
True
What is topical treatment for digital dermatitis aimed towards?
The treatment of mature and chronic lesions to reduce pain
Footbaths are important for the control of ____ digital dermatitis lesions.
early
From a distance, how does foot rot appear?
Generalized swelling of the foot that may extend up to or above the dew claws
Separation of the claws
Severe lameness
Cow frequently lifts the foot in pain
On close examination, how does foot rot appear?
Necrotic lesion of the interdigital skin
Foul-smelling
Febrile cow
Extreme sensitivity to touch
In rare cases - swelling but no lesion
Bovine foot rot is strongly influenced by _______ factors.
environmental
What is an important factor in the pathogenesis of bovine foot rot?
Injury of the interdigital skin by abrasion, maceration, chapping, or a heavy bacterial contamination
It is important to distinguish foot rot from what?
Foreign bodies, traumatic lesions, distal interphalangeal joint sepsis, and retroarticular and bulbar abscesses
What matters most in the treatment of claw lesions?
Corrective trimming and relief of weight bearing
What is the primary cause of abscess formation in cows claws?
Anaerobic bacteria which is why it is important to change the microenvironment from anaerobic to aerobic
