Lecture 19 3/24/25 Flashcards
Why is lameness in cattle an important issue?
-high priority producer concern because they can see it
-causes economic losses
-animal welfare concern
-it occurs very commonly
What are the economical impacts of lameness in the diary industry?
-reduced milk yield
-discarded milk
-decreased fertility rate
-increased culling rate
What are the economical impacts of lameness in cow-calf operations?
-limited grazing leads to less milk and lower calf weight
-lower fertility rate
-increased culling rate
What is the economical impact of lameness in feedlot operations?
direct reduction of feed conversion and weight gain
What are the behavioral changes seen in lame cattle?
-reluctance to walk
-decreased food and water intake
-loss of hierarchic status
-increased stress
-less likely to mount cows/reproduce
What are the physiological consequences of lameness in cattle?
-less daily weight gain
-decreased milk production
-reduced reproductive performance
What are the signs of normal gait in cattle?
-flat back
-minimal head bobbing
What are the signs of abnormal gait in cattle?
-head bob
-arched back
-short strides
-joint stiffness
-legs swinging in or out
-reluctance to bear weight on one foot
Which claw bears the most weight in the hindlimb?
lateral claw
Why is it important to know that most hoof problems affect the hind lateral claws?
animals with lateral claw issues will begin to bear weight on the medial claw
What are the statistics regarding the cause of lameness in cattle?
-90% of lameness cases originate in the foot
-90% of foot lameness occurs in the hind limbs
What is the composition of the foot?
-2 digits, numbers 3 and 4
-3 phalanges per digit
-1 distal sesamoid bone per side
-horn covers the claws
Which joints are present in the foot of cattle?
-fetlock joint (metacarpo(tarso)-phalangeal joint)
-PIP joints (proximal interphalangeal joints)
-DIP joints (distal interphalangeal joints)
Which foot joint experiences the most issues?
DIP joints
What are the characteristics of the claw?
-protects underlying sensitive corium
-dissipates concussion forces at impact to the ground during the stride
-3 components; wall, sole, and heel bulb
What are the characteristics of the hoof wall?
-has an axial wall inside/between the digits
-has an abaxial wall with dorsal (front of hoof) and abaxial components
-new hoof wall grows down from the coronary band
What are the characteristics of the corium?
-sensitive, vascular tissue below hoof wall
-contains blood vessels and nerves
-supplies nutrients to growing hoof capsule
-made of small, finger-like projections called laminae
-laminae interlock with hoof wall to form a strong bond
Which coria are present in the hoof?
-perioplic
-coronary
-laminar
-solar
What are the characteristics of the solar portion of the claw/
-produced by solar corium
-merges with horn of heel
-connected to wall by the white line
What are the characteristics of horn formation?
-living epidermis with highly mitotic cells are found between the dermis and the rest of the epidermis
-epidermis becomes keratinized as the horn grows towards the bottom of the foot
-the outermost layers of horn are cornified/fully keratinized
What are digital cushions?
3 parallel cylinders of loose connective tissue infiltrated by a variable amount of fat
What are the purposes of the digital cushions?
-compress and expand to absorb shock
-protect fragile inner structures
What happens if the digital cushions become too fatty?
they lose their springiness and are not as functional
What are the characteristics of the laminar corium?
-largest corium that produces the most laminae to interdigitate with hoof wall
-found along entire abaxial wall, around toe, and 1/3 of abaxial side
-produces white line
-suspends P3 in the claw; cow is in her claw, not on it
What are the characteristics of the deep digital flexor tendon?
-attaches on the P3 extensor process
-palmar/plantar to the distal sesamoid bone
Where does the superficial digital flexor tendon attach?
P2
What is the purpose of the palmar/plantar cruciate ligament?
X-shaped ligament that maintains the 2 claws together during weight bearing
**cow cannot function without this structure
What are the characteristics of the fetlock?
-contains the lateral and medial metacarpo(tarso)-phalangeal joints
-100% communication between the two joints
What are the three joints of the carpus?
-radiocarpal joint
-intercarpal joint
-carpometacarpal joint
Which joints in the carpus communicate with one another?
intercarpal and carpometacarpal joints
What are the four joints of the tarsus?
-tarsocrural
-proximal intertarsal
-distal intertarsal
-tarsometatarsal
Which joints in the tarsus communicate 100% with one another?
tarsocrural and proximal intertarsal
Why is it important that the lateral malleolus is NOT fused to the tibia in cattle?
on radiographs it appears as a radiolucent line; important to recognize it is NOT a fracture
What are the 3 joints within the stifle?
-femoropatellar
-medial femorotibial
-lateral femorotibial
Which joints in the stifle have 100% communication with one another?
femoropatellar and medial femorotibial
Which ligaments are present within the stifle?
-3 patellar ligaments
-2 collateral ligaments
-cranial and caudal cruciate ligaments
What is the purpose of the reciprocal apparatus?
ensures the stifle and hock move together
Which muscles contribute to the reciprocal apparatus?
-peroneus tertius
-gastrocnemius
What are the characteristics of the peroneus tertius?
-runs from extensor fossa of femur to medial side of tarsus
-the muscle that is typically ruptured when there are reciprocal apparatus issues
What is the sign of peroneous tertius rupture?
flexion of the stifle with extension of the tarsus
What is the sign of gastrocnemius rupture?
bearing weight on the hock
What is the suspensory ligament in cattle called?
interosseous medius muscle
Why must the nerves of the limbs be considered in cattle?
-can provide local anesthesia
-post-recumbency problems
-deficits can explain gait abnormalities
Which type of block can be used to anesthetize the entire foot?
4 point block
Which type of block can be used to anesthetize the entire forelimb?
brachial plexus block
Which nerve is at greatest risk of injury during recumbency?
radial nerve
Which syndromes can occur with tibial nerve paralysis?
-tibial paralysis
-tibial spasms
What is the importance of sciatic paralysis?
affects majority of limb and makes weight bearing very difficult
What are the characteristics of obturator paralysis?
-cannot adduct the limbs
-need non-slip floor and hobbles to prevent injury
What is a regional limb perfusion?
placement of a tourniquet on a limb prior to injection of anesthetic or antibiotics; drug circulates within the specified region rather than throughout the body
