Farm animal MSK disease Flashcards
(100 cards)
1
Q
Based on the AHDB Dairy Mobility Scoring system, what mobility score is appropriate for the following description?
Imperfect mobility
Steps uneven (rhythm or weight bearing) or strides shortened
Affected limb or limbs not immediately identifiable
A
Mobility score 1
2
Q
Based on the AHDB Dairy Mobility scoring system, what score is most appropriate for the following description?
Good mobility
Walks with even weight bearing and rhythm on all four feet and flat back
Long fluid strides possible
Tracking well - back foot lands where fores have been
A
Mobility score 0
3
Q
Based on the AHDH Mobility Scoring system, which score is most appropriate for the following description?
Severely impaired mobility
Unable to walk as fast as a brisk human pace (cannot keep up with healthy herd), uneven weight bearing on limb that is immediately identifiable and/or obviously shortened strides, usually arch at centre of back
A
Mobility score 3
4
Q
Based on the AHDB Mobility Scoring system, which score is most appropriate for the following description?
Impaired mobility
Uneven weight bearing on limb that is immediately identifiable and/or obviously shortened strides
Usually with arch at centre of back
A
Mobility score 2
5
Q
What action is most appropriate for a cow with mobility score 0?
A
- No action required
- Routine preventative foot trimming when/if required
- Record mobility at next scoring session
6
Q
What action is most appropriate for a cow with mobility score 1?
A
- Routine (preventative) foot trimming when/if required
- Further observation recommended
7
Q
What action is most appropriate for a cow with mobility score 2?
A
- Lame, will benefit from treatment
- Attend to case as soon as practically possible
- Lift foot to establish cause prior to treatment
8
Q
What action is most appropriate for a cow with mobility score 3?
A
- Very lame
- Will benefit from treatment, requires urgent attention and nursing
- Should not be made to walk far, keep on straw yard or at grass
- Culling may be only possible solution
9
Q
Where is the majority of lameness in cattle located?
A
Hind limbs
10
Q
List the non-infectious common foot lesions in cattle
A
- Sole bruising
- Sole/heel/toe ulcer
- White line disease
- Foreign body
11
Q
Describe the appearance of sole ulcers in cattle
A
- Very mild: sole discolouration yellow to pink
- More severe red to purple
12
Q
What causes sole bruising in cattle?
A
- Damage to corium (pressure) leading to leaking serum or blood being incorporated into new sole horn
- Sometimes sole too thin
13
Q
Outline the development of sole ulcers in cattle
A
- Pressure points towards back of sole, lead to poor horn formation and bleeding in the horn
- Flesh (corium) protrudes through ulcer
- When present, often outer claws of both hind feet
14
Q
Describe the appearance of white line disease in cattle
A
- Mild cases, wall separates from sole, sometimes with blood staining
- More severe cases become infected and pus is seen
- Pus can track up wall and burst out at coronary band or under sole to burst at heel
15
Q
List the infectious foot lesions of cattle
A
- Digital dermatitis
- Heel erosion
- Interdigital growth
- Foul
- Toe necrosis
16
Q
Outline the development of digital dermatitis in cattle
A
- Infection of skin caused by bacteria
- Raw, painful erosion of skin, most commonly above heel bulbs
- Can also be found at front of feet, between toes
- Chronic forms have rubbery hairs sprouting from lesion
17
Q
Outline the development of heel erosion in cattle
A
- Caused by enzymes produced by some bacteria which erode horn at heel
- Severe forms lead to deep pits and grooves
- Weight bearing surface of foot is lost
18
Q
Outline the development of interdigital growths in cattle
A
- Protruding flesh between toes caused by any chronic irritation e.g. by bacteria responsible for heel erosion or foul
- Can become superinfected with digital dermatitis
19
Q
Outline the development of heel ulcers in cattle
A
- Further back on foot than typical sole ulcer
- Sometimes tracks back to heel
20
Q
Outline the development of foul in cattle
A
- Caused by bacteria, enter through broken skin between the claws
- Lead to swelling and characteristic smell
21
Q
Outline the appearance of axial wall fissures in cattle
A
Appear as white line defect on inner wall, sometimes hard to spot
22
Q
Outline the development of toe necrosis in cattle
A
- Rotten toe
- May start as toe ulcer or split wall with deep infection
- Digital dermatitis bacteria may be involved, infecting exposed corium and preventing healing
23
Q
Outline the development of toe ulcers in cattle
A
- Particularly painful
- Often precipitated by thin soles
24
Q
What are the 4 main farmer factors for healthy feet in cattle?
A
- Reduce infection pressure
- Improve hoof shape and horn quality
- Reduce forces on foot (good cow flow, comfort)
- Early lameness detection and prompt,effective treatment
25
What is the ideal anterior wall length and angle in cattle?
- Length 90mm
| - Angle: 45-50degrees
26
What is the ideal heel height in younger and older cattle?
- Younger: 25-35mm
| - Older: 30-45mm
27
Outline the method for corrective foot trimming
- First cut: trim toe to 90mm, measure from coronary band, leave longer if foot very overgrown or cow is large
- Second cut: even out thickness of the sole, avoid over thinning, leave 5-7mm step at toe
- third cut: dish out to reduce weight bearing at main sole ulcer site
28
List your differentials for a calf presented with reluctance to stand, reluctance to suckle, positional dystocia, lame, swelling in lower left leg, pyrexia (39.4˚ C), and how would you proceed with this investigation?
- Septic arthritis, most likely systemic
- Physical trauma to joint from manipulation during calving
- Next: examine navel, joint tap, provide analgesia using one off dose of meloxicam
29
In a calf with septic arthritis that has occurred as a systemic spread from navel ill, outline a conservative treatment programme
- Meloxicam one off dose (or carprofen)
| - Antibiotics: systemic streptomycin + penicillin/amoxycillin
30
In a calf with septic arthritis that has occurred as a systemic spread from navel ill, outline an aggressive treatment programme
- Culture and sensitivity of fluid from joint tap
- Joint lavage using saline via 14-16Gneedle
- Local/regional antibioics e.g. regional vein or directly intra-synovial streptomycin, amoxycillin
- Analgesia with meloxicam
31
Identify risk factors for the development of septic arthritis
- High stocking density
- Lack of navel dipping
- Deep straw bedding managed poorly
- Dystocia (cow and calf feel worse, cow may have dropped colostrum prior to calving if long parturition etc.)
- Poor quality of colostrum/insufficient intake of colostrum
32
Briefly discuss the importance of lameness in farm animals
- Reduced productivity (e.g. milk yield)
- Involuntary culling
- Welfare
33
What are the 3 most important causes of lamenss in dairy cattle?
- Sole ulcers
- White line disease
- Digital dermatitis
- NB often considered together
34
Where does the majority of bovine lameness occur?
The lateral claw of the hind feet
35
Discuss the proposed pathogenesis of claw horn lesions in cattle
- Weight put through back of legs, concentrated on small area → lots of pressure
- Most pressure is on sensitive area of corium under pedal bone
- Excess pressure on dermis as a result of the calving effect, environmental factors, and changes to normal structures in the hoof
36
Explain the calving effect in the development of claw horn lesions in cattle
- Deterioration of the collagen fibres and connective tissues in the suspensory appratus leads to sinkage +/- rotation of the pedal bone
- Close to calving, pelvic relaxation occurs due to relation of tendons and ligaments, incl. suspensory apparatus
- Pedal bone may drop and crush the corium
37
Describe the structure and function of the suspensory apparatus in the bovine foot
- Collagen fibres running from P3 anchored in the dermal lamellae and claw capsule
- Suspend pedal bone within hoof capsule
38
Explain the changes to normal structures in the hoof that lead to excess pressure on the dermis in cattle
- Digital cushion changes following sole ulcers (more connective tissue, less fat tissue)
- Becomes less cushioning
39
Explain the importance of BCS with regards to the digital cushion in cattle
- Body fat is related to the content of fat within the digital cushion
- Fat content increases with age, poorly developed in heifers
- Fat cows = thick cushion, thin cow = thin cushion
- Thinning of digital cushion can occur as a result of loss of BCS, leading to lameness, further loss of body condition
40
Describe the normal weight bearing on the bovine foot
- Heel bulbs make first contact with the ground
- Digital cushion, sole, heel dermis dissipate concussive forces
- Elastic tissues expand laterally when compressed, transferring energy to the wall
- Weight distributed equally between claws
41
Explain the effect of concrete on pressure on the dermis of the foot in cattle
- Flattens and increases width of lateral claw
- Transfers part of load to central part of sole → increased pressure on dermis
- Overgrowth of lateral claw increases pressure on this area further
42
Explain how bony changes of the bovine foot can lead to excess pressure on the dermis
- P3 bony changes occur in diseased animals
- New bone formation (spiky processes on back of P3) associated with inflammatory process, incl. claw horn disease
- New bone compresses germinal epithelium
- More lame as a result of bony changes, so get more bony changes occurring and so on
43
Describe the structure and function of the sole corium in cattle
- Fills space between pedal bone and hoof capsule
- Contains blood vessels, nerves and other support structures
- Digital cushion dissipates force and transfers load to the wall during foot strike and limb loading
- Stratum germinativum produces sole horn
44
Give the ideal lengths and angles of the different parts of the bovine foot
- Anterior wall: 90mm
- Anterior wall to ground angle: 45-50degrees
- Heel height: 25-35mm
45
Discuss the consequences of toe overgrowth in cattle
- Overgrowth of toe shifts weight further back (toe angle <45degrees)
- More weight onto heel bulbs, less onto toes → not worn down as much → continual overgrowth
- Sole thickening also occurs in this region, exacerbating problem
46
Discuss the disparity in claw size that commonly occurs in cattle
- lateral claw (esp. HL) tends to overgrow as a result of abnormal gait, initial overgrowth forcing lateral claw to weight bear more, udder distension leading to leg swinging out to avoid contact
- Lateral claw more weight bearing normally, faster growth in response to wear
47
Briefly outline the method for claw trimming in cattle
- First cut: cut to length (90mm)
- Second cut: along sole, avoid overthinning, leave 5-7mm step at toe
- Third cut: reduce weight bearing at sole ulcer site by modelling axial aspect of claw
48
Outline how the adverse effects of foot trimming in cattle can be minimised
- Trim in small groups of cows to minimise wait time
- Start during or straight after milking
- Trim 1 week ahead of drying off date
- Provide water, food and lying space
- Provide clean, dry yards for holding and dispersing
49
What are the 5 principles of foot trimming in cattle?
- Correct toe overgrowth to correct food angle
- Spare heel, leave sole thickness
- Allow walls to bear most weight, take weight off sole ulcer site
- Remove weight from painful claws
- Remove dead/diseased horn
50
Outline the application of blocks to bovine feet
- Only to healthy claws
- To relieve weight on claw: trim down heel or apply block to sound claw
- Check size of block before clawing
- Place block over heel so weight bearing part of heel is covered
51
Outline your management approach to a sole ulcer in a cow
- Relieve weight on affected claw, if other claw healthy - apply block
- remove collar of bone
- Be hygienic
- Spray with antibiotic or copper gel
- Consider injectable antibiotics and analgesia
- Do not remove ulcer - may produce non-healing scar
52
Outline your management of sole bruising and thin soles in cattle
- Corrective trimming
- Do not make soles too thin
- Consider how standing time on concrete can be reduced
- Consider blocks applied to both claws if both claws are healthy
53
Outline your management of toe ulcers in cattle
- Usually occur due to over trimming or sharp/new concrete
- Place block on healthy claw
- Look for underlying cause and correct
- Formalin foot bath for herd (not cows with open sores)
54
Outline your management of white line disease in cattle
- Drain the pus
- Pare out ulcer to allow good drainage
- Cut away dead horn
- Use sharp knives to avoid cutting into quick and creating wall ulcer
55
Outline your management of white line abscesses in cattle
- Start with functional trim
- Remove disease tract in white line using sharp knife
- ensure drainage hole is made that will not block easily
- Keep cow in clean conditions
- Apply poultice and bandage if in straw yard
56
What are chronic white line infections/wall ulcers caused by in cattle?
- Delayed treatment
- Infection with digital dermatitis or other pathogens from environment/dirty knives
- Constant irritation from wet, sandy or slurry contaminated conditions
- Scarred quick
- Impaired healing capacities
57
Outline your management of interdigital growths in cattle
Veterinary treatment may require surgical removal or freezing
58
How does heel erosion develop in cattle?
- Standing in slurry
| - Pathogens found in slurry/wet conditions
59
Outline the treatment of heel erosion in cattle
Eroded heel should be removed, preserving as much healthy horn as possible
60
How does the hair form of digital dermatitis occur and how should this be treated?
- Chronic form of digital dermatitis
- Acts as reservoir of infection for the rest of the herd
- Vet may advise cutting lesion back, bandaging with antibiotics/copper sulphate, freezing, culling
61
What is "thimbling" in cattle? Treatment?
- Severe interruption of horn growth, usually following period of sickness
- Usually partly attached to the quick
- Keep removing loose parts of thimble that may be pulling on the quick
62
Outline the nursing and after care that should be implemented in the management of foot disease in cattle
- Increase lying time, reducing standing for milking
- Keep lesions clean and dry (separate nursing group, regular bandage changes)
- Re-examine and treat as necessary
- Relieve pain (NSAIDs, blocks)
63
List common mistakes that occur in the treatment of foot disease in cattle
- Over-trimming toe
- Leaving flat soles
- Removing healthy wall
- Applying blocks to diseased claws
- Blocks used that are too small for the claw
- Bandages left on for more than 3 days
64
List the surgical options for the treatment of deep digital sepsis in cattle
- Digital amputation
- Coring
- Navicular bone resection
- Drilling through and flushing affected area
65
What methods can be used to provide local analgesia of the bovine foot for surgery?
- Local infiltration, field and ring blocks
| - Regional anaesthesia (perineural or intravenous)
66
Outline the use of local infiltration, field blocks and ring blocks for local analgesia in cattle (drugs, method, effects)
- 2-3% lidocaine hydrochloride (NB no longer licensed) often add adrenaline
- Infiltrate either into or around the site to be desensitised to varying depths
- Produces local vasoconstriction
- Ring blocks preferable over perineural anaesthesia
67
Describe the method for perineural anaesthesia of the bovine forefoot (include which nerve is blocked)
- Subcut 5ml on medial border of extensor tendon at mid-carpal (radial)
- 2cm deep 5ml injection on medial border of deep flexor tendon, 5cm proximal to fetlock (median)
- 1cm deep 5ml injection on lateral border of deep flexor tendon 5cm proximal to fetlock (ulnar)
- Subcut 5ml injection between and just proximal to accessory digits (median and ulnar branches)
68
Describe the method for perineural anaesthesia of the bovine hind foot at mid-tarsal level, and which nerve is blocked
- Subcut 5ml injectioin directly over extensor tendon (superficial peroneal)
- 1.5cm deep 5 ml injection directly below extensor tendon (deep peroneal)
- 1cm deep 5ml injection on medial border of deep flexor tendon (medial plantar)
- 1cm deep 5ml injection on lateral border of the deep flexor tendon (lateral plantar nerve)
69
What are the 2 methods for perineural anaesthesia of the bovine hind foot?
- Mid-metatarsal (similar to forefoot)
| - Proximal to the hock
70
Describe the method for perineural anaesthesia proximal to the hock in the bovine foot, and the nerve blocked
- 20ml injection posterior and distal to lateral condyle of tibia (peroneal nerve)
- 20ml injection 10cm above summit of calcaneous just in front of the Achilles tendon on its medial aspect (tibial nerve)
71
Describe the method for intravenous regional analgesia in the cow
- Tourniquiet applied tightly around limb proximal to capus or hock
- 30-40ml of 2-3% lidocaine hydrochloride without adrenaline injected rapidly into any obvious superficial vein (radial vein on medial aspect of FL, or lateral saphenous in HL)
- Analgesia complete within 10-15 mins, interdigital space last area to lose sensation
72
Outline the method for digit amputation as a treatment of deep digital sepsis in cattle
- Apply tourniquet
- Prepare foot for surgery
- Scalpel incision along length of interdigtal space to depth of 2-3cm
- Place wiresaw in the cut, direct obliquely upwards and out (either saw through proximal P2 or distal P1)
- Curette away necrotic/infected tissue, and remove protruding interdigital fat
- Firmly bandage
- +/- Parenteral broad spec antibiotic
- Dressing to be changed every 2-3 days until covered in healthy granulation tissue (~2 weeks)
73
Discuss the prognosis and contraindications for a digit amputation in cattle
- Short average productive life, although some continue to be productive for years expectancy
- Not an option for heavy animals e.g. breeding bulls, or animals on slatted floors
74
Describe the method for coring in the treatment of deep digital sepsis in cattle
- Apply block to sound claw
- Insert hoof knife through sole of affected claw into necrotic area
- Move in coring motion to produce 3-4cm hole on plantar aspect of foot, extending to full depth of the lesion
- Must allow hole to stay open
- +/- Parenteral broad spec antibiotic
75
Discuss the prognosis and aftercare for coring in the treatment of deep digital sepsis in cattle
- Reasonable success rate
- Must lift and inspect daily for blockage, flush with running water
- May end up in toe up position (disruption of DDFT) unless wired to normal digit
76
Compare coring and navicular bone resection for the treatment of deep digital sepsis in cattle
- Navicular bone resection more refined than corin
- More time req. more surgical skill,
- Inevitably damage DDFT so need to wire to sound digit
77
Describe the method for navicular bone resection for the treatment of deep digital sepsis in cattle
- Incision made across full width of affected bulb, just proximal to skin-horn junction
- Wedge of tissue incl. digital cushion, DDFT, navicular bone and associated ligs and soft tissue removed, and as much articular cartilage curetted from DIP joint as possible
- If all necrotic tissue removed, close as normal
- If wound is left open, antiseptic dressing applied, change q2-3 days until healthy granulation tissue
- +/- parenteral broad spec antibiotics
78
Outline the method for drilling and flushing for the treatment of deep digital sepsis in cattle
- Drill through affected area, abaxial to axial approach
- Direct proximally and dorsally to emerge on dorsolateral aspect of digit just proximal to coronary band to drain septic arthritis of DIP joint
- Abaxial to interbulbar approach for retroarticular abscesses
- Once hole drilled, insert drainage tube
- Firmly knot distal end of drainage tube, puncture tube with 16G needle to make lots of small holes
- Feed tube from caudal aspect of foot, up to the cranial aspect so knot is snug with bulbs
- Bandage free end to cow's leg in figure of 8 pattern
- Carry out flushing with lots of pressure on plunger to expel blood blots or debris from fenestrations in tube (50ml syringe)
79
Describe the aftercare, prognosis/advantages for drilling and flushing in the treatment of deep digital sepsis in cattle
- Flushing via drainage tube twice daily
- Prognosis: earlier and more satisfactory resolution of problem vs other surgical options
- Less traumatic, does not necessarily result in total disruption of the attachment of the DDFT
80
Describe the typical clinical signs of botulism in cattle
- Progressive, symmetrical flaccid cranial and peripheral nerve paralysis beginning in HLs, progresses cranially
- Initially sternal recumbency with head round to one side, then lateral recumbency
- Respiratory depression
- Dry MM
- Initially diarrhoea, then constipation
- Dilated pupils, poor PLR
- May be observed from 24hours up to 17 days after exposure to toxin
- Some cases may present as sudden deaths
- Fatality ~90%
81
Which toxins are usually associated with clinical botulism in cattle?
C or D
82
Describe the typical clinical signs of botulism in sheep and goats
- Arched back with drooping tail, head and neck
- In early stages, have unusual stilted gait
- Muscles of mastication and swallowing less obviously affected vs cattle
83
Describe the clinical signs of botulism in birds
- Progressive flaccid paralysis progressing cranially from legs
- Initially may be sitting and reluctant to move
- May seem lame
- Wings droop
- Eyelid paralysis
- Respiratory depression/failure, gasping when handled
- Broilers may have diarrhoea
- Neck feathers loose
84
Which toxin type is associated with atypical botulism?
Type B
85
Describe the clinical signs of atypical botulism
- Diarrhoea
- Profuse salivation
- regurgitation and vomiting
86
Describe the clinical signs of periparturient botulism in cattle
- Indigestion
- Non-infectious acute laminitis
- Ataxia
- Stiff, stilted gait
- Paralysis
- Engorged veins
- Oedema in the legs, udder and dewlap
- Increased respiratory effort
- Tucked up abdomen
- Sudden death
87
List the metabolic differentials that may cause similar clinical signs as seen with botulism in cattle and sheep
- Hypocalcaemia
- Hypophosphataemia
- Postparturient paresis
- Ketosis
- Hypokalaemia
88
List the infectious differentials that may present similarly to botulism in cattle and sheep
- Bacterial, viral or chlamydial encephalitides
- e.g. Histophilus somnus
- Listeriosis
- Paralytic/dumb rabies
- BSE
- Brain abscess
89
List the toxic differentials that may present similarly to botulism in cattle and sheep
- Hepatoencephalotpahy
- Lead poisoning
- OP toxicity
90
List the differentials that may present similarly to botulism in birds
- Newcastle disease
- Avian influenza
- Marek's disease
- Avian encephalomyelitis
- Lead poisoning
- Myopathies e.g. ionophore toxicity
- Alphachloralose poisoning
91
Describe the approach to the diagnosis of botulism
- Demonstration of toxin in serum or viscera e.g. liver of animals that have not undergone autolysis
- GI contents or faeces (low value for diagnosis)
- Detection of toxin in feed/water
- PM: nothing pathognomic, use to rule out other conditions
- Mouse inoculation test is gold standard but not sensitive enough to confirm diagnosis
92
List the risk factors for botulism in ruminants
- Access to broiler litter
- Access to decaying carcass material
- Access to ware contaminated by decaying carcass material
- Access to spoiled/decaying plant crops/vegetable material
93
Discuss the food safety and human health implications of diagnosing botulism in sheep and cattle
- Low risk to human health
- All milk and meat from affected and unaffected in contact sheep in groups diagnosed with botulism is withheld for 14 days from onset of last case, or 17 days from date of last exposure to toxin
94
Outline the prevention of botulism in sheep and cattle
- Do not use broiler litter
| - Vaccines available for types C and D
95
Give the 2 forms of clostridial myositis in cattle, and give the causative agents
- Blackleg: Clostridium chauvoei
| - Malignant oedema: many clostridial species, early always associated with wound infection
96
What is blackleg?
Gangrenous myositis due to activation of latent C chauveoi spore infection
97
What agents cause false/pseudo black leg?
C novyi or septicum spores
98
Outline the aetiology of blackleg
- G-ve, anaerobic, sporulating
- Soil organism
- Following ingestion, spores localise in spleen, liver and muscles
- Vegetative form produces toxins capable of inducing local muscle necrosis and toxaemia
- Trigger mechanisms unknown, likely lower oxygen tension and muscle damage
- After activation, rapid bacterial multiplication and toxin formation = gangrenous lesion and systemic toxaemia
99
Describe the clinical signs of C. chauveoi in cattle
- Death
- Signs relate to site
- Limbs: lameness, swelling of upper part, initially hot and painful, later cold and emphysematous
- Tongue: protrusion, marked resp. distress
- Sublumbar muscles: stiffness, reluctance to move
- Marked depression, anorexia, rapid pulse, high temp (>40)
- Later: dyspnoea, recumbency, coma and death within 12-24 hours
100
Describe the pathology associated with blackleg in cattle
- Acute
- Blackened, dry crepitant muscle, spongy appearance, rancid odour, pale yellow serous fluid surrounds affected muscle, becomes more bloodstained
- Bloodstained froth exudates from body orifices
