Infectious foot disease Flashcards
Why are infectious foot diseases important?
- Make animals lame
- Important animal welfare issue
- Reduce milk production
- Expensive to control
Where are bovine digital dermatitis lesions located?
Above the coronet between the heel bulbs
How does bovine digital dermatitis affect productivity?
- Major cause of lameness: welfare issue
- Milk drop
- Increased culling rate
- Increased labour costs
Which organism is most frequently reported in bovine digital dermtitis?
Spirochaetes always seen in BDD lesions; not seen in normal skin
Evidence suggests that … are the aetiological agents of Bovine digital dermatitis
Treponemes
How is bovine digital dermatitis diagnosed?
Visual - lameness and lesion score
How is bovine digital dermatitis treated?
- Footbaths: chemical or antibiotic
- Topical treatments e.g. tetracycline (blue spray)
- Penicillin or macrolides (BUT milk withhold & antibiotic stewardship issues SO NOT USED!)
How is bovine digital dermatitis spread?
- Outbreaks within herds tend to be season dependent, with the highest incidence in winter (housing) months
- Cattle can “carry” disease onto new farms
- Cleaner farms have fewer outbreaks
- Ruminant GI tract, slurry, direct contact and foot trimming equipment all identified as infection reservoirs/transmission routes.
How does Contagious Ovine Digital Dermatitis grossly affect the foot?
- Starts at the coronary band
- Frequent lesions result in loss of the entire foot horn capsule
- Substantial pain
What are the pathogenic organisms causing Contagious Ovine Digital Dermatitis?
Spirochaetes
Treponemes
How is Contagious Ovine Digital Dermatitis diagnosed?
Visually - lameness and lesion score
How is Contagious Ovine Digital Dermatitis treated?
- Footbaths: chemical or antibiotic
- Topically: tetracycline
- Amoxicillin/penicillin or macrolides
What is the primary clinical sign on ovine footrot?
Extremely painful -> rapid weight loss
Can get death from starvation and thirst
What is the primary pathogenic agent that causes ovine footrot?
Dichelobacter nodosus
How does ovine foot rot grossly affect a sheep’s foot?
Begins as an interdigital dermatitis, then interdigital hoof wall lesions leading to separation of hoof from underlying tissue
How is ovine foot rot treated?
- Treatment = hoof trimming?? + topical disinfectants or antibiotics: 5–10% formalin, 5% zinc sulfate or oxytetracycline spray.
- Formalin + zinc sulfate in footbaths.
- Systemic amoxicillin and streptomycin = alternative.
- Vaccination
‘Scald’ in sheep is also known as?
Ovine interdigital dermatitis
What is the most common cause of lameness in sheep?
Ovine interdigital dermatitis
Describe the pathological features of Ovine interdigital dermatitis
- Occurs when wet underfoot
- No under-running of hoof wall or sole & no foul smell
- Now generally considered an early presentation of footrot
- Red/pink inflammation of skin between claws with white/grey pasty ‘scum’ on top
Bovine Foul in the Foot is also known as?
Interdigital necrobacillosis
Which pathogen is the main cause of interdigital necrobacillosis?
Fusobacterium necrophorum
Describe the disease/signs of interdigital necrobacillosis
- Sudden onset, acute disease
- Severe lameness
- Animal frequently holds leg in air to relieve pressure
- Swelling of interdigital space
- Fever, Anorexia
- Reduced milk yield
How is interdigital necrobacillosis treated?
- 3 day systemic penicillin, oxytet or macrolide
- Foot bathing with disinfectants to control
What are some common characteristics of pathogens that cause infectious foot diseases?
Gram negative and anaerobic also tend to be rods (helical rods in some cases), motile and fastidious.
