Lameness (Yr 4)

Question 1

what are the common causes of lameness in sheep relating to the feet?

Answer 1

footrot (scald, benign, virulent)
CODD
white line disease
toe granuloma
foot abscess
interdigital hyperplasia
overgrown, foreign bodies

Question 2

what is benign footrot also known as?

Answer 2

scald or interdigital dermatitis

Question 3

what is the main pathogen associated with scald (benign footrot)?

Answer 3

Dichelobacter nodosus (also Fusobacterium necrophorum)

Question 4

what are the clinical signs of scald (benign footrot)?

Answer 4

lameness
interdigital skin inflamed/discharging
smells
(no horn under-running or separation)

Question 5

what predisposes sheep to benign footrot (scald)?

Answer 5

interdigital moisture/damage (warm wet conditions)
high stocking rates (housing)

Question 6

what is virulent footrot?

Answer 6

interdigital dermatitis plus progressive under-running of sole starting medially

Question 7

how do horns with virulent footrot appear?

Answer 7

grey necrotic pungent smelling sole

Question 8

what is the primary aetiological agent of footrot?

Answer 8

Dichelobacter nodosus

Question 9

is Dichelobacter nodosus anaerobic or aerobic?

Answer 9

anaerobic

Question 10

what are the virulence factor of Dichelobacter nodosus?

Answer 10

fimbrae (allows movement)
proteases (necrosis of horn)

Question 11

how can benign footrot (scald) be treated?

Answer 11

oxytetracycline spray
formalin/zinc sulphate foot bath
(systemic antibiotics not necessary)

Question 12

how is virulent footrot treated?

Answer 12

long acting oxytetracycline or amoxicillin (first line)
macrolides if you want longer acting (tilmicosin…)
do not trim
treat quickly and isolate

Question 13

should lame sheep with footrot have their feet trimmed?

Answer 13

no - delays healing and spreads disease

Question 14

what does CODD stand for?

Answer 14

contagious ovine digital dermatitis

Question 15

how lame are sheep with CODD?

Answer 15

severe lameness

Question 16

how does CODD appear clinically?

Answer 16

ulcerative/proliferative lesion begins at coronary band
progressive under-running of hoof wall downwards
hoof sloughs off

Question 17

how is CODD graded?

Answer 17

1 - coronary band lesion
2 - <50% horn capsule separated
3 - >50% hoof capsule separated
4 - healing but still active
5 - healed

Question 18

can CODD lesions heal?

Answer 18

yes - but hoof often left deformed

Question 19

how deep does infection of CODD spread?

Answer 19

can reach bone

Question 20

what is the causative agent associated with CODD?

Answer 20

treponeme bacteria (same as digital dermatitis in cattle)
Dichelobacter nodosus and Fusobacterium necrophorum also found

Question 21

what are the risk factors for CODD?

Answer 21

late summer to early autumn
lush, wet pasture with high stocking

Question 22

how is CODD treated?

Answer 22

isolate
long acting amoxicillin (treat until cure)
macrolide for second line longer acting

Question 23

what is the five point plan?

Answer 23

vaccinate twice yearly with footvax
treat lame sheep quickly
biosecurity
reduce environmental challenge
cull chronically lame sheep

Question 24

what is footvax for?

Answer 24

footrot (Dichelobacter nodosus)

Question 25

what can footvax be used for?

Answer 25

prevention and treatment of footrot (can be used in an outbreak) some protection against CODD

Question 26

what is the issue with the footrot vaccination?

Answer 26

oily adjuvant so can cause lumps/abscesses (don't use near shearing or lambing)

Question 27

what is the typical footvax protocol?

Answer 27

2 doses 4-6 weeks apart then 6 monthly boosters

Question 28

what biosecurity should be taken for foot lesions for bought in stock?

Answer 28

isolate and treat with footvax return if signs of footrot/CODD

Question 29

what is white line disease?

Answer 29

separation of white line

Question 30

when may white line disease lead to lameness?

Answer 30

when sensitive tissue gets exposed or impacted with stones/mud abscess formation (tracks up the horn)

Question 31

how can white line disease be treated?

Answer 31

no infection - leave or trim slightly abscess - trim to drain pus

Question 32

what causes a toe granuloma?

Answer 32

overtriming (chronic irritation/infection) chronic foot disease

Question 33

how are toe granulomas treated?

Answer 33

intravenous regional anaesthesia cut off and cauterise granulation tissue

Question 34

how is interdigital hyperplasia treated?

Answer 34

trim and clean (antibiotics if secondary infection present)

Question 35

what predisposes sheep to laminitis?

Answer 35

high energy/concentrate diet

Question 36

how is laminitis treated?

Answer 36

treat underlying disease NSAIDs

Question 37

what causes a pedal joint abscess?

Answer 37

interdigital infection spreads into the interphalangeal joint structures, pus then tracks abaxially to emerge at the coronary band

Question 38

what are the clinical signs of pedal joint abscesses?

Answer 38

severe lameness swollen, warm foot widened interdigital space purulent discharge

Question 39

how can pedal joint abscesses be treated?

Answer 39

flush and antibiotics digit amputation

Question 40

where do you disarticulate for a digit amputation?

Answer 40

between P1 and P2

Question 41

what is strawberry footrot?

Answer 41

proliferative scab lesion of distal limb usually caused by orf or dermatophillus

Question 42

how is strawberry footrot treated?

Answer 42

systemic/topical antibiotics (penicilin) move to dry area

Question 43

what causes white muscle disease?

Answer 43

selenium and vitamin E deficiency

Question 44

what animals is white muscle disease seen in?

Answer 44

young, rapidly growing lambs

Question 45

how does white muscle disease present?

Answer 45

stiff and reluctant to move swollen/painful skeletal muscles

Question 46

how can white muscle disease be diagnosed?

Answer 46

raised glutathione peroxidase in blood

Question 47

what are some causes of infectious arthritis?

Answer 47

neonatal infections (Streptococcus dysgalactaie) tick pyaemia (Staphylococcus aureus) Erysipelothrix