Lameness in calves Flashcards
1
Q
Arthritis definition
A
- inflammation of joints (synovial membrane and articular surfaces)
2
Q
Septic arthritis definition
A
- arthritis due to infection
3
Q
Polyarthritis definition
A
- multiple joint affected
- septic or immune-mediated
4
Q
Septic arthritis aetiopathogenesis in calves <3w old
A
- FPT is primary risk factor
-> omphalophlebitis (mixed bacteria) or septicaemia (Gram-negatives)
-> circulating bacteraemia
-> bacteria localise on articular surfaces - polyarthritis is common
- calves might also show other CS related to sepsis e.g. meningitis, uveitis, enteritis
- prognosis = guarded to poor
- multiple joints = poorer prognosis
- FPT = poorer prognosis
5
Q
Septic arthritis aetiology calves >3w old
A
- may be subsequent to penetrating wounds (T.pyogenes - opportunistic bacteria seen in lots of cattle infections)
- Mycoplasma bovis: typically BRD also present +/- otitis media/interna (head tilt), often stifles affected
- circulating bacteraemia: intestinal origin e.g. Salmonella spp, respiratory origin e.g. H.somni, M.bovis
6
Q
Septic arthritis: diagnosis
A
- clinical exam and history
- arthrocentesis: clip & scrub area, large gauge needle (16G or 18G), sedate if needed, culture sample
- imaging: rarely done as rarely adds info on top of CE
7
Q
Septic arthritis presenting signs
A
- pain -> lameness (NWB if 1 leg affected)
- affected joints painful and hot to touch, more chronic cases might not be
- joint swelling variable -> pyogenic bacteria = greatest swelling
- general signs variable present e.g. pyrexia, inappetence, weight loss
- co-morbidities may be present: omphalophlebitis in young calves, endocarditis in older animals
- chronic: fibrin development -> will be swollen but less painful and may not be hot, less likely to see general signs
8
Q
Septic arthritis CE
A
- acute cases usually pyrexic and dull
- observe the calf walking: lameness will be present, keen to lie down
- if recumbent see if calf will stand: will be difficult or maybe not possible
- examine joints: usually painful, usually reduced RoM -> may be very impaired or ankylosed if chronic
- hock, stifle and carpus most commonly affected
- older calves -> often single joint affected
- young calves -> typically multiple joints
9
Q
PM finding of a septic arthritis joint
A
- lots of fibrin
- synovial fluid very turbid
- can see frank pus instead of synovial fluid
10
Q
Arthrocentesis of a septic arthritis joint
A
- volume: high
- ease of obtaining fluid: usually easy
- gross appearance: turbid, yellow, may be purulent, may be more watery/less viscous
- leukocytes µL: high numbers (4000-8000), predominantly neutrophils (80-90%)
- protein: high (TP = 3.2-4.5g/dL)
- microbiology: bacteria (or other pathogens) might be culture or visible on Diff Quid (although not always)
11
Q
Septic arthritis tx
A
- analgesia: NSAIDs
- antibiotics: select based on likely organisms, penicillin/oxytet/TMPS (parenteral, licensed, broad spec, penetrate synovial membrane), long course recommended (3w), intra-articular antibiotics (described but rarely used, no licensed formulation)
- joint lavage (+ antibiotics + NSAIDs): better results than antibiotics + NSAIDs alone
- supportive care: feeding, bedding, good nursing
12
Q
Septic arthritis likely pathogens
A
- Trueperella pyogenes
- Fusobacterium necophorum
- Staphylococcal spp
- E.coli
- Salmonella spp
- Mycoplasma bovis
- Erysipelothrix rhusiopathiae
13
Q
Trueperella pyogenes causing septic arthritis (presentation, common? antibiotic susceptibility)
A
- presentation: any age of calves, concurrent omphalophlebitis in calves <3w
- common? very common, the most common isolate in older calves and adults
- antibiotic susceptibility: penicillin, amoxicillin, oxygen, TMPS
14
Q
Fusobacterium necophorum causing septic arthritis (presentation, common? antibiotic susceptibility)
A
- presentation: any age of calves, concurrent omphalophlebitis in calves <3w, may also see calf diphtheria, faecally spread
- common? yes, esp if unhygienic feeding practices
- antibiotic susceptibility: amoxicillin, TMPS, oxytet
15
Q
Staphylococcal spp causing septic arthritis (presentation, common? antibiotic susceptibility)
A
- presentation: any age of calves, concurrent omphalophlebitis in calves <3w
- common? yes
- antibiotic susceptibility: penicillin, amoxicillin, oxytet, TMPS
16
Q
E.coli causing septic arthritis (presentation, common? antibiotic susceptibility)
A
- presentation: calves <3w, concurrent septicaemia
- common? yes
- antibiotic susceptibility: amoxicillin, TMPS, oxytet
17
Q
Salmonella spp causing septic arthriti (presentation, common? antibiotic susceptibility)s
A
- presentation: older calves
- common? sporadic
- antibiotic susceptibility: amoxicillin, TMPS, oxytet
18
Q
Mycoplasma bovis causing septic arthritis (presentation, common? antibiotic susceptibility)
A
- presentation: calves 3-6m, may have concurrent resp dz, may have concurrent otitis media/interna
- common? yes on some farms, rare on others, may be under diagnosed, seen in beef + dairy
- antibiotic susceptibility: TMPS, oxytet, NOT penicillins
19
Q
Erysipelothrix rhusiopathiae causing septic arthritis (presentation, common? antibiotic susceptibility)
A
- presentation: older calves
- common? rare (most commonly seen in sheep, pigs & turkeys)
- antibiotic susceptibility: penicillin, amoxicillin, oxytet, TMPS
20
Q
Joint lavage for septic arthritis
A
- best results if done early (acute stages) -> too much fibrin when chronic
- use sterile, isotonic (0.9%) saline or Hartmann’s
- through and through technique
- can be done on farm, no special equipment needed
- surgical prep
- use LA: deposit 2-5ml procaine sc at sites of needle placement
- sedate if needed: Xylazine or detomidine
- place needles on each side of the joint as far apart as possible
- calves = 16-18G needle
- adults = 14-16G needle
- inject lavage solution: large joints (e.g. stifle) at least 3L, small joints at least 250ml
- giving set tubing can help continuous flushing
- to express remaining joint fluid add firm pressure pressure with fingers
- apply light dressing if needed
21
Q
WMD
A
- white muscle dz
22
Q
WMD aetiology
A
- vit E/selenium deficiency -> nutritional (aka nutritional muscular atrophy)
- dams fed diet insufficient in vitE/Se (calves don’t get enough in utero, from colostrum & milk)
- young, fast growing animals: calves <6m most often affected, has been reported up to 2y, lambs and kids as well as calves
- often following sudden expectation of exercise: calves reared indoors then turns out at 6-8w
- but is reported in housed animals
23
Q
WMD clinical signs
A
- recumbency and difficulty standing: inability to stand for more than a few mins
- stiff, trembling legs
- weakness elsewhere e.g. neck
- may rotate distal hindlimb from hocks if able to walk
- gluteal, shoulder and dorso-lumbar musculature palpably enlarged and firm
- other signs related to (striated) muscle affected: intercostal mm = dyspnoea, myocardium = cardiac arrhythmias, tongue mm = inability to suckle
24
Q
WMD diagnosis
A
- CE & hx: known deficient pastures
- urinalysis: myoglobin present
- biochem: elevated creatine kin and aspartate aminotransferase
- biochem: low selenium or glutathione peroxidase
- liver biopsy: low selenium and vit E
- PM: less myoglobin present so muscles look very pale
- glutathione peroxidase (GSH-Px): delayed increase in response to selenium admin (4-6w), can be tested in calves that have been recently treated, lithium heparin (green top) or EDTA (purple top) tube [check with lab], selenium protein, preferred test
- selenium: only useful for untreated calves, lithium heparin or plain tube
25
Q
WMD tx
A
- vit E / selenium: single dose usually sufficient but can be repeated after 2-4w if needed, myocardial involvement = poorer tx response
- NSAIDs as needed
26
Q
WMD prevention
A
- ensure adequate selenium intake of dams during late pregnancy, selenium -> transplacental and colostral, vit E -> colostral
- provide supplementation to dams if deficient pastures: long acting (bolus) injections, intraruminal bolus, oral dosing, addition to ration
- can also supplement calves
27
Q
Vit E/selenium supplementation
A
- barium selenate: sc depot injection, 9-12m duration
- Cosecure: sodium selenate: intraruminal bolus, 6-12m duration
- zinc, cobalt, selemnium & b12: sodium selenate, oral drench, 1-3m duration
- selenium minerals: added to feed, unreliable due to variations in individual cow feeding
28
Q
Fractures
A
- most common causes = calving injuries (neonates) and accidents (any age)
- casts/splints are most common methods of on farm management
- cattle have excellent healing capability and neonates are quick to heal
29
Q
Types of fractures
A
- distal metacarpal/metatarsal
- femoral fractures
- growth plate fractures
30
Q
Distal metacarpal/metatarsal fracture (cause, fracture type, management, prognosis)
A
- common cause: excessive traction on rope/chain during calving
- fracture type: typically closed
- management: external coaptation (casting), surgical repair
- prognosis: both methods = excellent if closed (80=90%) but poor if open
31
Q
Femoral fractures (cause, fracture type, management, prognosis)
A
- common cause: pressure from dam’s pelvis during breech presentation
- fracture type: closed
- management: surgical repair, conservative management
- prognosis: surgical repair = fair to good, conservative management = guarded to fair
32
Q
Growth plate fractures (cause, fracture type, management, prognosis)
A
- common cause: accidents
- fracture type: open or closed
- management: external coaptation if closed, surgical repair or euthanasia if open
- prognosis: closed with external coaptation = excellent, open with surgical repair/euthanasia = guarded to poor
33
Q
Principles of casts/splints in calves
A
- best candidates = transverse or short oblique fractures and Salter-Harris type 1 and 2 growth plate fracture
- x-ray is best to decide ^ but can make decisions based on careful CE
- in general, the more proximal the fracture the more difficult it will be to immobilise
- closed fractures only -> examine skin carefully for wounds
- include the hoof in all casts
34
Q
Salter-Harris classification
A
I = no displacement
II = chip fracture of the metaphysis
III = epiphyseal involvement
IV = both epiphyseal and metaphysical involvement
V = compression fracture
35
Q
Cast application
A
- use commercially available casting material and cotton woof/soffban for padding
- lay animal in lateral recumbency with fractured leg uppermost (sedate or GA to avoid fracture reduction)
- carefully pad bony prominences and place cotton wool between claws
- cast limb in a neutral position starting at fracture site
– overlap casting material by 50% each roll
– apply minimal tension on 1st layer and gradually increase with each layer
– use 6-8 layers of casting material for calves <150kg
– include embryotomy wire (in giving set tubing) to aid removal
36
Q
Aftercare
A
- keep calf in small, well bedded pen for 6-8w
- calf must be checked daily: signs of pain, signs of wetness or cracks in cast, alterations in gait/weight bearing (should fully weight bear within a few days of casting and continue to do so until cast removed), sudden alterations in limb use -> remove cast and assess
- replace the cast every 3-4w in neonates to accommodate fast growth
- remove after 6-8w
37
Q
Soft tissue injuries (age, treatment)
A
- seen any age
- treat conservatively: NSAIDs, rest/restricted exercise, deep bedding
38
Q
Congenital deformities
A
- joint deformities
- contracted tendons
39
Q
Contracted tendons
A
- large calves (bend weird in utero and so tendons don’t have space to stretch)
- flexor tendons
- mild cases -> exercise and encourage weight bearing
- more severe cases -> splint or cast
- oxytet?
