Infectious causes of lameness Flashcards
Describe the aetiology of bovine digital dermatitis
Three groups of anaerobic spirochetes bacteria repeatedly found in lesions
1. Treponema medium/ vincentii-like
2. Trepnema phagedenis like
3. Treponema pedis
Describe the epidemiology of bovine digital dermatitis
Under ideal induction conditions with inoculation of skin wounds, lesions can develop within 21 days
slurry and infected animals act as reservoir
Where are digital dermatitis lesions generally found
plantar surface of the hindfoot
Describe M-0 stage of digital dermatitis
normal healthy skin
no visible lesion
no sign of DD
Describe M1- stage of digital dermatitis
early stage
focal active
red-grey
less then 2cm
Describe M2 stage of digital dermatitis
acute
bright red
ulcerative
painful lesion
more than 2cm
Describe M2 (proliferative ) stage of digital dermatitis
same as M2 as well as
Hyperkeratotic epidermal growth
Increased heel height
Describe M3 stage of digital dermatitis
Healing
Non-painful
Firm brown/black scab
Often seen after topical treatment
Describe M4 stage of digital dermatitis
Chronic stage
Non-painful
Dys/Hyper- keratotic overgrowth
Brown-gray colour
Decribe M4.1 stage of digital dermatitis
Chronic M4
With some reactivation M1 areas on top
Describe how to diagnose bovine digital dermatitis
clinical observation whilst foot trimming- gold standard
Describe the individual treatment of digital dermatitis
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
what type of digital dermatitis would you generally use antibiotic to treat
severe lesion (M2)
Spray licensed antibiotic (oxy/chlro- tetracycline, thiamphenicole)
Describe the ideal footbath for a cow
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
what is the rationale for footbathing to prevent digital dermatitis
To limit the progression of the early stages (M1) to clinical disease (M2) and the recrudescence of inactive (M3 and M4) lesions
List the 3 most common chemicals used in cow footbaths
copper sulphate (4-5%)
Formaldehyde (2-4%)
Myriad of footbath agents (largely untested)
List 6 risk factors for bovine digital dermatitis
environmental hygiene
cleanliness score and hock score
biosecurity
trimming utensils
footbath
parity and lactation- first parity increased risk
What is another name for Interdigital necrobacillosis
Foul in the foot
what causes Interdigital necrobacillosis
Fusobacterium necrophorum (Gram-negative)- 2 subtypes:
1. ssp necrophorum
2. ssp funduliforme
synergically acting with Porphyromonas levii and Prevotella intermedia
List the clinical signs of Interdigital necrobacillosis
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
List the risk factors for interdigital necrobacillosis
poor surfaces
poor hygiene
Worm, moist environmental conditions
Other causes of lameness increase the risk of the disease
Beginning of lactation (metabolic status)
Describe how to diagnose interdigital necrobacillosis
signs are pathognomonic once foot is examined
Describe how to treat interdigital necrobacillosis
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)
what is the prognosis of interdigital necrobacillosis
good if treated early
otherwise poor
