Lameness in calves Flashcards
What is the primary risk factor for septic arthritis in calves<3 weeks old? What are other causes? What is the prognosis?
FTPI is primary risk factor - then omphalophlebitis and septicaemia
Bacteria localise on articular surfaces
Polyarthritis common
Prognosis = guarded to poor
Multiple joints = poorer Px
FTPI = poorer Px
What causes septic arthritis in calves > 3 weeks old?
- May be subsequent to penetrating wounds - T.pyogenes
- 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
How would you diagnose septic arthritis in calves?
- Clinical examination and history
- Arthrocentesis
- Clip and scrub area
- Large gauge needle (16G or 18G)
- Sedate if needed
- Imaging -> rarely done
What are the presenting signs of septic arthritis?
- Pain -> lameness (may be non-weightbearing)
- Affected joints painful and hot to touch - more chronic cases might not be
- Joint swelling variable -> pyogenic bacteria = greatest swelling
- General signs variably present - E.g. pyrexia, inappetence, weight loss
- Co-morbidities may be present
- Omphalophlebitis -> young calves
- Endocarditis -> older animals
What should you include in your clinical exam investigating possible septic arthritis?
- Acute cases usually pyrexic and dull
- Observe the calf walking
- Lameness will be present
- Calf will be keen to lie down
- If recumbent, see if calf will stand
- Will be difficult or maybe not possible
- Examine joints
- Usually painful
- Usually reduced range of motion -> may be very impaired or ankylosed if chronic
- Hock, stifle and carpus most commonly affected
- Older calves -> often single joint
- Young calves -> typically multiple joints
What synovial fluid analysis findings would you expect to get from arthrocentesis of a joint with septic arthritis?
- Volume - High
- Ease of obtaining fluid - Usually easy
- Gross appearance - Turbid, yellow, may be purulent, may be more watery (i.e. less viscous)
- Leucocytes (μL) - High numbers (4000-8000), predominantly neutrophils (80-90%)
- Protein - High (TP = 3.2-4.5 g/dL)
- Microbiology - Bacteria (or other pathogens) might be cultured or visible on Diff Quik (although not always)
How would you treat calves with septic arthritis?
- Analgesia - NSAIDs
- Antibiotics
- Select based on likely organisms
- Penicillin/oxytetracycline/TMPS -> parenteral, licensed, broad spec, penetrate synovial membrane
- Long course recommended - 3 weeks
- NB. 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
When is it best to perform joint lavage on septic arthritic joints? How are they performed?
Best results if done early (i.e. acute stages) -> too much fibrin when chronic
Protocol
* Use sterile, isotonic (0.9%) saline or Hartmanns
* Can be done on farm, no special equipment needed
* Surgical prep
* Use local anaesthesia - Deposit 2-5ml procaine subcutaneously at sites of needle placement
* Sedate if needed - Xylazine or detomidine
* Calves = 16-18G needle
* Adults = 14-16G needle for adults
* Place needles on each side of the joint as far apart as possible
* Inject lavage solution
* Large joints = at least 3L
* Small joints = at least 250ml
* Giving set tubing can aid continuous flushing
* Express remaining joint fluid
- Apply firm pressure with fingers to express fluid as much as possible
- Remove needles
- Apply light dressing if needed
What causes white muscle disease in calves?
- Vitamin E/selenium deficiency -> nutritional (AKA Nutritional muscular dystrophy)
- Dams fed diet insufficient in VitE/Se
- Young, fast growing animals
- Calves < 6 months most often affected - Has been reported up to 2 years
- Lambs and kids as well as calves
- Often following sudden expectation of exercise
- Calves reared indoors then turned out at 6-8weeks
- But is reported in housed animals
What clinical signs are associated iwht white muscle disease?
- Recumbency and difficulty standing
- Inability to stand for more than a few mins
- Stiff, trembling legs. Weakness elsewhere (e.g. neck)
- May rotate distal hindlimbs 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
How can you diagnose and treat white muscle disease?
Diagnosis
Clinical exam and history
- Known deficient pastures
Clinpath
* Urinalysis = myoglobin present
* Biochem (in house/at lab) = elevated creatine kinase (CK) and aspartate aminotransferase (AST)
* Biochem (at lab) = low selenium or glutathione peroxidase
* Liver biopsy (at lab) = low selenium and vitamin E
Treatment
- Vitamin E/Selenium
- Single dose usually sufficient but can be repeated after 2-4 weeks if needed
- Myocardial involvement = poorer treatment response
- NSAIDs as needed
How can you prevent white muscle disease in calves?
- Ensure adequate selenium intake of dams during late pregnancy
- Selenium -> transplacental and colostral
- Vitamin E -> colostral
- Provide supplementation to dams if deficient pastures
- Long acting (bolus) injections
- Intraruminal bolus
- Oral dosing
- Addition to ration
- Can also supplement calves
What are the most common causes of fractures in calves? How are they managed? What is the prognosis?
- 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
What fractures are the best candidates for casts/splints in calves?
Best candidates = transverse or short oblique fractures and Salter-Harris type 1 and 2 growth plate fractures
* X-ray is best to decide this but can make decisions based on careful c/exam
* 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
What aftercare is needed for calves with casts/splints?
- Keep calf in small, well bedded pen for 6-8 weeks
- Calf must be checked daily
- Signs of pain
- Signs of wetness or cracks in cast
- Alterations in gait/weightbearing (should weightbear fully 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 3-4weeks in neonates to accommodate fast growth
- Remove after 6-8weeks
When are soft tissue injuries seen in calves? How are they treated?
Seen any age
Treat conservatively
* NSAIDs
* Rest/restricted exercise
* Deep bedding
What calves are most affected by contracted tendons? How are these managed?
- Large calves
- Flexor tendons
- Mild cases -> exercise and encourage weight bearing
- More severe cases -> splint or cast
- Oxytetracycline?
