Lameness in calves

Question 1

Arthritis definition

Answer 1

• inflammation of joints (synovial membrane and articular surfaces)

Question 2

Septic arthritis definition

Answer 2

• arthritis due to infection

Question 3

Polyarthritis definition

Answer 3

• multiple joint affected
• septic or immune-mediated

Question 4

Septic arthritis aetiopathogenesis in calves <3w old

Answer 4

• 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

Question 5

Septic arthritis aetiology calves >3w old

Answer 5

• 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

Question 6

Septic arthritis: diagnosis

Answer 6

• 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

Question 7

Septic arthritis presenting signs

Answer 7

• 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

Question 8

Septic arthritis CE

Answer 8

• 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

Question 9

PM finding of a septic arthritis joint

Answer 9

• lots of fibrin
• synovial fluid very turbid
• can see frank pus instead of synovial fluid

Question 10

Arthrocentesis of a septic arthritis joint

Answer 10

• 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)

Question 11

Septic arthritis tx

Answer 11

• 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

Question 12

Septic arthritis likely pathogens

Answer 12

• Trueperella pyogenes
• Fusobacterium necophorum
• Staphylococcal spp
• E.coli
• Salmonella spp
• Mycoplasma bovis
• Erysipelothrix rhusiopathiae

Question 13

Trueperella pyogenes causing septic arthritis (presentation, common? antibiotic susceptibility)

Answer 13

• 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

Question 14

Fusobacterium necophorum causing septic arthritis (presentation, common? antibiotic susceptibility)

Answer 14

• 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

Question 15

Staphylococcal spp causing septic arthritis (presentation, common? antibiotic susceptibility)

Answer 15

• presentation: any age of calves, concurrent omphalophlebitis in calves <3w
• common? yes
• antibiotic susceptibility: penicillin, amoxicillin, oxytet, TMPS

Question 16

E.coli causing septic arthritis (presentation, common? antibiotic susceptibility)

Answer 16

• presentation: calves <3w, concurrent septicaemia
• common? yes
• antibiotic susceptibility: amoxicillin, TMPS, oxytet

Question 17

Salmonella spp causing septic arthriti (presentation, common? antibiotic susceptibility)s

Answer 17

• presentation: older calves
• common? sporadic
• antibiotic susceptibility: amoxicillin, TMPS, oxytet

Question 18

Mycoplasma bovis causing septic arthritis (presentation, common? antibiotic susceptibility)

Answer 18

• 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

Question 19

Erysipelothrix rhusiopathiae causing septic arthritis (presentation, common? antibiotic susceptibility)

Answer 19

• presentation: older calves
• common? rare (most commonly seen in sheep, pigs & turkeys)
• antibiotic susceptibility: penicillin, amoxicillin, oxytet, TMPS

Question 20

Joint lavage for septic arthritis

Answer 20

• 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

Question 21

WMD

Answer 21

• white muscle dz

Question 22

WMD aetiology

Answer 22

• 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

Question 23

WMD clinical signs

Answer 23

• 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

Question 24

WMD diagnosis

Answer 24

• 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

Question 25

WMD tx

Answer 25

- vit E / selenium: single dose usually sufficient but can be repeated after 2-4w if needed, myocardial involvement = poorer tx response - NSAIDs as needed

Question 26

WMD prevention

Answer 26

- 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

Question 27

Vit E/selenium supplementation

Answer 27

- 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

Question 28

Fractures

Answer 28

- 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

Question 29

Types of fractures

Answer 29

- distal metacarpal/metatarsal - femoral fractures - growth plate fractures

Question 30

Distal metacarpal/metatarsal fracture (cause, fracture type, management, prognosis)

Answer 30

- 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

Question 31

Femoral fractures (cause, fracture type, management, prognosis)

Answer 31

- 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

Question 32

Growth plate fractures (cause, fracture type, management, prognosis)

Answer 32

- 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

Question 33

Principles of casts/splints in calves

Answer 33

- 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

Question 34

Salter-Harris classification

Answer 34

I = no displacement II = chip fracture of the metaphysis III = epiphyseal involvement IV = both epiphyseal and metaphysical involvement V = compression fracture

Question 35

Cast application

Answer 35

- 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

Question 36

Aftercare

Answer 36

- 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

Question 37

Soft tissue injuries (age, treatment)

Answer 37

- seen any age - treat conservatively: NSAIDs, rest/restricted exercise, deep bedding

Question 38

Congenital deformities

Answer 38

- joint deformities - contracted tendons

Question 39

Contracted tendons

Answer 39

- 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?