Flashcards in Production animal lameness 1 and 2 - BOVINE Deck (48)
Commonest causes of dairy lameness
1. sole ulcer (SU)
2. white line disease (WLD)
3. digital dermatitis (DD)
- toe necrosis (d/t treponemes)
- deep digital sepsis
- interdigital hyperplasia/ growth
- wall ulcer
Location - sole ulcer
always axial to midline and at heel (dairy)
What can WLD progress to?
chronic walled off ulcer
What can DD lead to?
Hx important for lameness workup
- which lactation
- how long calved (should be 100-150d, could dry off if late lactation)
- previous foot problems/ other problems (is this a chronic or complicated problem)
- how long is this problem (peracute?)
- what tx has she had
- is she pregnant, milking well on cull list? (determine if worth tx surgically)
Describe Dairy Co Mobility Score 0
- walks with even weight bearing and rhythm on all 4 feet, with a flat back
- long fluid strides possible
Describe Dairy Co Mobility Score 1
- steps uneven (rhythm or weight bearing) or strides shortened, affected limb(s) not immediately idenitifiable
Describe Dairy Co Mobility Score 2
uneven weight bearing on a limb that is immediately identifiable and/or obviously shortened strides (usually with an arch to centre of back)
Describe Dairy Co Mobility Score 3
unable to walk as fast as a brisk human pace (cannot keep up with healthy herd) and signs of score 2
Where is lameness most commonly located?
Hind feet (92%) on lateral claw (65% but 80% for SU or WLD)
How many lameness cases affected leg and other sites (rather than feet)?
What % lameness are d/t foot problems?
How do you clean the foot and do a functional trim?
- sawdust?/ hose?/ disinfectant
- Dutch % step foot trimming
How do cows react to hoof testers?
very subtle reactions in cows vs horses. you must test all the way round both claws.
Outline the objective of the 5 steps of the Dutch method
1. create a foot angle of 52 degrees
2. create balance b/w claws
3. transfer weight from sole onto wall, toe and heel
4. remove weight from a painful claw
5. remove loose or sharp horn
Outline how you trim toe to correct length (step 1)
start with inner hind claw or outer fore claw (the most normal claw). If length already correct, then sole depth correct, move to step 2. Measure (at least) 7.5cm from coronary band (placing fingers in interdigital space). Some large cows need 8cm. Trim sole so 80mm weight bearing stopping before sole thinning ('give' on thumb pressure) trim until white line just reappears at tip of toe. Once foot angle restored in 1st claw, use as a template for 2nd claw.
Outline step 4 of the dutch method
relieve weight off painful claw - trim back 2/3 painful claw or apply block to healthy claw.
Name 3 different block materials
What is step 5 of the dutch method?
remove loose/under-run horn and hard ridges (in most cases only back 1/3 of inner hind claw should be tidied. In most cases only back 2/3 of outer hind claw should be tidied)
What are the 2 commonest problems with foot trimming?
- overshortening the toe
- making sole too thin
What should you examine the lame foot for?
- visible lesions (sole, wall, heel, skin but multiple lesions common)
- pain with hoof testers and finger pressure on soft tissues
- feel and look b/w claws
- softening at heel or coronary band
- swelling above coronary band or in heel (sign that infection is tracking more deeply)
- redness (skin, haemorrhage in horn is approx 2 months historic)
Tx - uncomplicated sole ulcer
- if GT present - chop off
- if corium is swollen - don't chop ff
- to distinguish: corium is innervated whilst GT isn't. Determine by cow reaction to pressure.
Tx - sole ulcers
- treat early
- Dutch 5 step trim
- Nursing/ clean yard (severe cases)
- promote wound healing (nothing that cauterises)
Prognosis - SU
- generally ok
- recurrence next lactation possible
- reduced fertility and lifespan (by 450d)
- milk drop (500L) should recover in several wks
Theories - aetiology - SU
- stone penetration
- laminitis d/t hot ration and acidosis (controversiaL)
Outline laminitis in cows
- acidosis doesn;t directly appear to cause claw horn lesions
- most claw horn disease stems from environmental conditions
- BCS and claw horn growth rates may be important in SU pathogenesis
- Biotin may improve claw horn quality and reduce white line lesions
- high dry matter diets will reduce claw horn lesions (likely d/t drier dung)
Effective herd interventions - SU
- increase straw bedding per cow
- put heifers onto straw rather than cubicles for first 4 months post-calving
* both reduce trauma aspects of SU pathogenesis
Outline current theory on SU pathogenesis
(- SU originate at point where flexor tendon attaches to flexor process of P3)
Change in lamina structure around calving (probably hormonally mediated) occurs prior to inflammation --> allows some P3 movement away fro claw horn. Digital cushion thickness relates to BCS --> predisposes some cows to trauma through sole --> trauma --> change in shape of claw --> claw overgrowth --> viscious cycle of trauma on an overloaded claw with a thin digital cushion and inflammation in an enclosed space --> full SU several weeks later.
Uncomplicated WLD tx
- drain pus
- pare out to allow good drainage
- cut away dead horn (can be done 2 wks later)
- use sharp knives to avoid cutting into corium
- apply a block
- NSAIDs especially if localised swelling of corium
- AB (e.g. OTC spray)