Lameness in sheep 1 + 2 Flashcards
List some causes of lameness in sheep
- Footrot
- Contagious ovine digital dermatitis
- White line disease
- Foot abscess
- Interdigital hyperplasia
- Over grown claws
- Foreign body
- Arthritis
- Infections
- Fracture
- Muscular disease
- Neurological
Why is benign footrot a problem?
- Widespread in U.K 97% of flocks affected
- Flock level problem
What is the main pathogenic cause of benign footrot?
Dichelobacter nodosus
What are the clinical signs of benign footrot?
- Lame
- Interdigital skin inflamed, discharge, smell
- No horn under running
- Damage to skin may predispose to bacterial infection (damp conditions underfoot, frost and/or mechanical damage from long grass, thistles)
What is footrot?
Interdigital dermatitis plus….
Progressive under - running of sole of hoof horn starting at medial aspect of sole and progressing laterally
What is the primary aetiological agent causing footrot?
Dichelobacter nodosus
What is another possible aetiological agent of footrot?
Fusobacterium necrophorum
What are the main risk factors for footrot?
- Wet underfoot conditions
- Warm
- Muddy
- Where they gather
- Genetics
What is the treatment for benign footrot/interdigital dermatitis/scald alone no under-running of horn?
Topical treatment
Oxytetracycline spray
Foot bathing in antiseptic solutions e.g. formalin
Systemic antibiotics usually not necessary
Describe an appropriate foot bathing routine for benign footrot
- Antiseptic needs to be exposed to infected inter-digital area to be effective (approx 2 minutes depend on product)
- Feet clean beforehand
- Solution correct concentration
- Solution correct depth
- Dry standing afterwards (concrete)
- Repeat as necessary
What is the treatment for footrot (under-run horn)?
- Treat as quickly as possible
- Isolate lame sheep
- Treat individuals/groups of sheep
- Injectable long acting antibiotics best treatment
- Long acting oxytetracycline or amoxicillin
May require repeat treatments
Is trimming recommended for lame sheep? why?
Trimming and topical treatment is not recommended as a method to treat or control footrot
- Trimming diseased feet delay healing
- Trimming may spread disease hands and clippers
- Studies have shown that if you treat the infection with antibiotics the foot shape will return to normal alone
Describe the clinical appearance of contagious ovine digital dermatitis
- ulcerative/proliferative lesions start at the coronary band
- Progressive under running of the hoof wall
- Hoof sloughs off
- Often mixed infection in flocks with footrot
Describe grades 1 to 5 of contagious ovine digital dermatitis
Grade 1 = coronary band lesion only
Grade 2 = Less than 50% of horn capsule separated
Grade 3 = 50-100% of the hoof capsule off
Grade 4 = Healing but active lesion still present
Grade 5 = Healed
What are the risk factors for contagious ovine digital dermatitis?
- Seasonal in later summer/early autumn
- Large flock size
- Lowland/lush pasture
- Prevalence of footrot
How is contagious ovine digital dermatitis treated?
- Isolate affected
- LA amoxicillin (usually require repeat injections)
- Treat until clinical cure
- Macrolides licensed for sheep useful as long acting
How is contagious ovine digital dermatitis treated?
- Isolate affected
- LA amoxicillin (usually require repeat injections)
- Treat until clinical cure
- Macrolides licensed for sheep useful as long acting
What are some key features of managing infectious foot disease?
As soon as individual animal is seen lame it should be treated
- Welfare
- Disease spread
- Law!!
Contagious flock level problem often necessary to treat whole flock
Footrot massive risk factor for CODD so vital to control both together
What are the aims of the 5 point plan?
- Reduce disease challenge
- Build resistance
- Establish immunity
What are the 5 points of the 5 point plan for infectious lameness disease control?
- Vaccinate twice yearly with footvax
- Treat lame sheep quickly
- Biosecurity
- Environmentally challenge
- Cull chronically lame sheep
Describe the benefits of the footrot vaccine
- Treats and Prevents footrot
- Cure rates 70-100% reported
- Very useful product on many farms, where struggling to keep on top of lameness particularly low staff numbers, large units and where prompt individual treatment isn’t feasible
What are the 4 contraindications for FootVax
- Oily adjuvant can cause injection site lumps
- Not used prior to shearing
- Not use close to lambing
- Not use if sheep had moxidectin 1%
Describe the dosing schedule for FootVax
- Initial vaccination 2 doses 4-6 weeks apart
- 6 monthly booster at risk periods
What are some biosecurity considerations for managing infectious lameness disease
Bought in sheep
- Don’t buy in new diseases or new strains of disease.
- Isolate
Be aware of anthelmintic resistance
Treat scab
Check for footrot lesions
Treat all sheep with Footvax
Describe how environmental hygiene can be used in the management of infectious foot diseases
- Keep handling areas as clean as possible
- Foot trimming equipment clean and disinfect
- Wet muddy areas in the fields and housing can be good areas for disease to spread
- Move buckets and feed troughs
- Fix leaky water drinkers
- Dry out gateways (hard core)
- Bedding dry
If a sheep has had 2-3 cases of lameness what should be done? Why?
Cull
- Some sheep harbor infection in their feet, spreading it in the flock
- Welfare
- Less likely to get pregnant, and rear healthy lambs
- More susceptible to other diseases
Describe the features of white line disease
- White Line separation common
- Don’t cause lameness unless sensitive tissue affected - impaction with stones/mud, abscesses formed
How is white line diseases treated?
No infection just separation of sole from wall
- Leave
- Can carefully trim out area of separation
Abscess
- Heat, pain, swelling affected claw
- May burst out at coronary band
- Trim if necessary to release pus, avoid damaging sensitive tissue
What is the main causes of toe granulomas?
Over trimming – exposing sensitive laminae underneath
How are toe granulomas treated?
- Intravenous regional anaesthesia
- Cut back granulation tissue
- Cauterise disbudding iron to stop bleeding and ensure granuloma removed
How do sheep with laminitis present?
- Reluctant to stand due to lameness on all four limbs.
- When standing, hold all limbs close together under the abdomen
- The digits are warm to touch with increased digital pulses.
What can predispose a sheep to laminitis?
- Excess access to high energy or cereal-based feed
- Acute disease such as metritis or mastitis
How is laminitis treated?
NSAIDs
Address underlying cause
What is the cause of a pedal joint abscess in sheep?
Extension of interdigital infection into the distal interphalangeal joint structures.
Pus then tracks abaxially across the distal interphalangeal joint to emerge at abaxial coronary band.
What are the clinical signs of a pedal joint abscess?
- Severely lame
- Swollen foot
- Widened interdigital space
- Purulent discharging sinus maybe present on the abaxial coronary band.
How is a pedal joint abscess treated?
- Flush and antibiotics
- Digit Amputation
Where does digital amputation occur?
Between P1 and P2
Which drugs are used for sedation and local anaesthesia in a digital amputation?
Sedation - xylazine im
LA - Procaine
What is strawberry footrot and its causes?
- Proliferative scab lesion distal limbs
- Usually orf & Dermatophilus
What is the cause of white muscle disease?
Selenium and vitamin E deficiency
How does white muscle disease present?
- Stiffness and reluctance to move.
- Progressing over several weeks to inability to stand
- Skeletal muscle maybe swollen and painful on palpation
Which group of animals are most commonly affected by white muscle disease?
Groups of young, rapidly growing, lambs grazing pasture or crops deficient in vitamin E and selenium.
How is white muscle disease diagnosed?
Raised glutathione peroxidase levels in blood
How does a sheep with a fracture present?
- Sudden onset lameness of varying severity but commonly non-weight bearing
- Pain, swelling, and crepitus may accompany the site of closed fractures.
- Pain, swelling, haemorrhage, crepitus and exposed bone will be seen in open fractures.
What is the cause of rickets?
Vitamin D deficiency
How does rickets present?
- Lameness, stiffness.
- Swollen joints, angular limb deformities
How is rickets diagnosed and treated?
- Dx Blood Vitamin D levels
- Tx Vitamin D and calcium supplementation
What is the agent that causes neonatal arthritis infections?
Streptococcus dysgalactiae
