Locomotor diseases

Question 1

Causes of lameness (7)

Answer 1

• Scald - interdigital dermatitis
• Footrot
• CODD
• Toe granuloma
• Toe abscess
• Shelly hoof/white line disease
• Over trimming

Question 2

Scald (Ovine interdigital dermatitis)

Answer 2

Dichelobacter nododus (same as foot rot)
Moderate lameness
Can lead to foot rot
Most common in young sheep on lush pastures where feet are moist most of the time
Interdigital space is inflamed, moist, and very painful
May be some maceration and necrosis of skin at the skin-horn junction
Heal spontaneously as the feet dry out, can accelerate using footbath with 5% formalin or 10% zinc sulphate
Oxytet spray on individual animal

Question 3

Foot rot

Answer 3

Dichelobacter nodosus
Severe lameness
Sensitive to low pH so rarely seen on acid soils
Interdigital space becomes inflamed and moist, then progressive necrosis of the stratum spinosum layer of epidermis causing separation of the outer epidermis from the horn
Inject long acting antibiotics, NSAIDs, and topical spray application

Question 4

Types of foot baths

Answer 4

3-5% formalin - cheap but toxic
10% zinc sulphate or copper sulphate - more expensive but less painful to open feet

Question 5

Contagious ovine digital dermatitis (CODD)

Answer 5

Starts at coronary band so damaged underrun horn doesn’t reform
Very severe
Multibacterial aetiology (Spirochaetes, D. nodosus + F. necrophorum)
Adults more likely than lambs, and more frequent in back feet
Housing may increase prevalence
Treat with amoxicillin/penicillin/tetracyclines and pain control with NSAIDs

Question 6

White line disease

Answer 6

White line (junction of wall horn and sole horn) weakened by laminitis or overgrowth of abaxial wall
Can be a portal for entry of infection potentially leading to abscess formation or infection
Usually a single leg is involved
Treat by to create drainage
Antibiotics indicated

Question 7

Foot abscess

Answer 7

Severe lameness
Penetrating foreign body
Deep abscess of the foot Fusobacterium necrophorum +/- Trueperella pyogenes
Treat by establishing drainage plus penicillin
May require digit amputation

Question 8

Contracted tendons

Answer 8

Unknown aetiology
Usually bilateral
Affects forelegs more than hindlegs
If severe may not be able to stand
Some become normal within a day
Pain relief may help during stretching of legs

Question 9

Redfoot

Answer 9

Seen in new born lambs
Uncertain aetiology
Autosomal recessive disease caused by a defect of the epithelium, leading to detachment of the horn so horn matrix is exposed
Severe lameness
Antibiotic treatment with pen/strep can allow lesions to heal the effect is only temporary so usually euthanised

Question 10

Bacterial septic arthritis

Answer 10

A suppurative arthritis that occurs in 1st month of life
Usually S. dysgalactiae but could be other organisms
Bacteraemia followed by localisation of infection
Bacterial multiplication occurs in the synovial membrane
Treatment must be given early, joint capsules hard to penetrate

Question 11

Enzootic staphylococcal infection of lambs (tick pyaemia, spinal abscess)

Answer 11

Young growing lambs grazing on land infested with ticks (Ixodes ricinus)
Caused by Staphylococcus aureus
Related to tick borne fever
Abscesses occur in many parts of the body
Parenteral antibiotics - penicillin

Question 12

Erysipelothrix arthritis

Answer 12

Erysipelothrix rhusiopathiae
Acute and chronic forms
Particularly affects growing lambs
Chronic lameness
Follows tail docking and castration or dipping
Early treatment with penicillin is indicated
Zoonosis

Question 13

Laminitis

Answer 13

Inflammation of the laminae suspending the pedal bone
Tends to be a flock problem based on diet
Lame, tucked up posture, arched back, heat and pain on palpation of affected feet, anorexia
Suspend rapidly fermentable carbohydrate feeding, NSAID prolonged administration, together with foot trimming
Correct feeding regimes

Question 14

Interdigital fibroma

Answer 14

Benign growth originating from the connective tissue at the skin/horn junction of the interdigital space
Can become ulcerated and infected
Antibiotic therapy to remove infection
Surgical removal
Don’t retain offspring for breeding

Question 15

Interdigital granuloma

Answer 15

Damage to hoof horn exposing sensitive laminae (overzealous foot trimming)
Forms granulation tissue and chronic inflammation
Lameness often of one limb
Restriction under LA

Question 16

Strawberry foot rot

Answer 16

Does not affect the feet but a condition of the skin of the lower legs
Caused by infection with Dermatophilus congolensis
+/- Orf
Localised area of ecudative dermatitis with scab formation
Lesions usually heal spontaneously in 5-6 weeks

Question 17

Caprine arthritis encephalitis

Answer 17

Causes chronic arthritis lesions in goats
Sometimes associated with mastitis, pneumonia
Carpi are usually all affected
Treat with NSAIDs initially but no treatment once established

Question 18

Selenium/Vit E deficiency (stiff lamb disease)

Answer 18

Both are required for normal anti-oxidant function
Nutritional myopathy
May be found dead (cardiac arrest)
Stiffness, weakness, muscle tremors, swollen muscles, possibly respiratory distress
PM: pale skeletal muscles, calcified striations, muscle damage

Question 19

Osteodystrophic conditions

Answer 19

Diseases of bone affecting structural development and strength, leading to bone weakness, lameness, skeletal distortion, and secondary fractures
- Osteoporosis
- Osteomalacia
- Rickets
- Stunted growth

Question 20

Osteoporosis

Answer 20

Reduction in the proteinacious matrix formation and a lack of mineralisation of matrix
Reduction in the amount of trabecular bone occurs and there is increased porosity of cortical bone
The bone is more fragile than normal

Question 21

Osteomalacia

Answer 21

Reduction in mineralisation of matrix; the amount of matrix is normal
Osteomalacia occurs in adult animals

Question 22

Rickets

Answer 22

Limited to the growing skeleton
A juvenile variant of osteomalacia
Poor mineralisation of growth plates and arrest of endosteal ossification

Question 23

Stunted growth

Answer 23

Sub-optimal bone growth
Bones are small but of normal matrix and mineralisation

Question 24

Bentleg, bowie

Answer 24

Growing lambs
Front legs bowed
Fast growing animals and/or phosphorus deficient

Question 25

Cappie, double scalp

Answer 25

Bones of skull are soft
Frontal bone can be depressed into frontal sinus

Question 26

Toxic osteodystrophies

Answer 26

• Chronic lead poisoning: leads to osteoporosis
• Secondary copper deficiency (high molybdenum): osteoporosis
• Fluorosis (industrial): mottled teeth, exostoses
• Vitamin D over dosing: scoliosis, hypercalcaemia, osteoporosis, and rickets

Question 27

Spondylosis

Answer 27

Extensive new bone formation on spinal vertebrae +/- ventral bridging between vertebrae
Rams are particularly at risk and the condition can lead to failure to serve
It causes immobility of the spine with discomfort
May result in spinal fracture