Infectious causes of lameness

Question 1

Describe the aetiology of bovine digital dermatitis

Answer 1

Three groups of anaerobic spirochetes bacteria repeatedly found in lesions
1. Treponema medium/ vincentii-like
2. Trepnema phagedenis like
3. Treponema pedis

Question 2

Describe the epidemiology of bovine digital dermatitis

Answer 2

Under ideal induction conditions with inoculation of skin wounds, lesions can develop within 21 days
slurry and infected animals act as reservoir

Question 3

Where are digital dermatitis lesions generally found

Answer 3

plantar surface of the hindfoot

Question 4

Describe M-0 stage of digital dermatitis

Answer 4

normal healthy skin
no visible lesion
no sign of DD

Question 5

Describe M1- stage of digital dermatitis

Answer 5

early stage
focal active
red-grey
less then 2cm

Question 6

Describe M2 stage of digital dermatitis

Answer 6

acute
bright red
ulcerative
painful lesion
more than 2cm

Question 7

Describe M2 (proliferative ) stage of digital dermatitis

Answer 7

same as M2 as well as
Hyperkeratotic epidermal growth
Increased heel height

Question 8

Describe M3 stage of digital dermatitis

Answer 8

Healing
Non-painful
Firm brown/black scab
Often seen after topical treatment

Question 9

Describe M4 stage of digital dermatitis

Answer 9

Chronic stage
Non-painful
Dys/Hyper- keratotic overgrowth
Brown-gray colour

Question 10

Decribe M4.1 stage of digital dermatitis

Answer 10

Chronic M4
With some reactivation M1 areas on top

Question 11

Describe how to diagnose bovine digital dermatitis

Answer 11

clinical observation whilst foot trimming- gold standard

Question 12

Describe the individual treatment of digital dermatitis

Answer 12

Clean, remove matted hair and “scab’
dry lesion
apply topical (ab or non-ab)
+/- bandage needs removing after a few days
repeat applications to improve recovery

Question 13

what type of digital dermatitis would you generally use antibiotic to treat

Answer 13

severe lesion (M2)
Spray licensed antibiotic (oxy/chlro- tetracycline, thiamphenicole)

Question 14

Describe the ideal footbath for a cow

Answer 14

rule of thumb- one litre solution per cow passage
must be cleaned and refilled after a maximum of 180 cow passes
it should assure the immersion of all feet and cover the entire foot

Question 15

what is the rationale for footbathing to prevent digital dermatitis

Answer 15

To limit the progression of the early stages (M1) to clinical disease (M2) and the recrudescence of inactive (M3 and M4) lesions

Question 16

List the 3 most common chemicals used in cow footbaths

Answer 16

copper sulphate (4-5%)
Formaldehyde (2-4%)
Myriad of footbath agents (largely untested)

Question 17

List 6 risk factors for bovine digital dermatitis

Answer 17

environmental hygiene
cleanliness score and hock score
biosecurity
trimming utensils
footbath
parity and lactation- first parity increased risk

Question 18

What is another name for Interdigital necrobacillosis

Answer 18

Foul in the foot

Question 19

what causes Interdigital necrobacillosis

Answer 19

Fusobacterium necrophorum (Gram-negative)- 2 subtypes:
1. ssp necrophorum
2. ssp funduliforme

synergically acting with Porphyromonas levii and Prevotella intermedia

Question 20

List the clinical signs of Interdigital necrobacillosis

Answer 20

damage to the skin on foot
sudden onset moderate to severe lameness
anorexia
swelling of soft tissues above and around the coronary band and between the digits
characteristic foul smell
Hot, inflamed and painful
“Split” in interdigital space, which discharges pus and necrotic tissue

Question 21

List the risk factors for interdigital necrobacillosis

Answer 21

poor surfaces
poor hygiene
Worm, moist environmental conditions
Other causes of lameness increase the risk of the disease
Beginning of lactation (metabolic status)

Question 22

Describe how to diagnose interdigital necrobacillosis

Answer 22

signs are pathognomonic once foot is examined

Question 23

Describe how to treat interdigital necrobacillosis

Answer 23

Wash and flush with plenty of clean water
Debridement of necrotic tissue if present
Parenteral antibiotics for 3-5 days ( Category D= Sulphamethoxypyridazine and Oxytetracycline)

(Category C= pen and strep and tylosin)

Question 24

what is the prognosis of interdigital necrobacillosis

Answer 24

good if treated early
otherwise poor