Skin conditions Flashcards
What is the scientific name for rain scald and how does it infect the cow?
Dermatophilosis
There needs to be initial skin damage before the pathogen can enter then needs mositure
What will you see with a rain scald infection?
Exudative epidermatitis followed by scab and crust formation and alopecia
Animals are not itchy
How can you diagnose and treat rain scald?
History of wet weather
Stained smear of scab and skin biopsies
Treatment includes parenteral antibiotics penicillin and oxytet
What are the common ways abscesses are formed?
Dirty needles and injections during wet weather
What should you do if you see an abscess forming on a cow?
Generally don’t cause pain
Incise, drain and flush with hose
What is the main cause of cellulitis in cattle and how does it cause it?
Truperella pyogenes
Penetrating wounds
Very painful
A cow has developed submandibular swelling. What are some of you differentials?
Actinomyces bovis- lumpy jaw
Actinobacillus- Woody tongue
What is black spot or black pox and where does it occur?
Necrotic lesion at the teat end from bacterial infection
What are the causes of black spot and common isolates?
High vacuum and over milking
Staph aureus and fusobacterium necrophorum
How do you treat black spot?
Tie up the back leg first because this is going to be a painful procedure
Open teat end and introduce antibiotics
Disinfect the teat
Should you incise or stick needles into haematomas?
Not if you don’t need to because it can harbour infection and turn into an abscess
If the cow cant walk you have to do something but otherwise just leave it
What is the significance of ringworm in dairy cattle?
Caused by a fungus trichophyton and cattle become infected when they come into contact with fences and gates etc that have the fungus
No real clinical significance and spontaneous recovery
What is papillomatosis and how can you treat it?
Caused by bovine papilloma virus mainly in cattle
How is papillomatosis spread?
Few ways including direct contact with infected cow or fomites
Flies and lice
What kind of lesions does bovine papular stomatitis cause?
Shallow to slightly raised papules on the MM and may coalesce
Only superficial lesions unlike FMD
Is there a zoonotic risk for bovine papular stomatitis?
Yes, can get painful nodular skin lesions
How is bovine papular stomatitis spread?
Suckling calves or milking machines
What do pseudocowpox lesions look like and where are they located?
Horse shoe shaped papules on the teats and rarely the udder
Is there any significance of pseudocowpox in a herd?
Little inconvenience and often overlooked
Mechanical transfer by milking so will go through the herd most likely
What signs and lesions are seen with bovine herpes mammillitis?
Oedema of teats, vesicle formation and scab formation
Post-oedema results in gangrenous look about the teat
What herpes virus cauases mammillitis and pseudo lumpy skin disease?
Bovine herpesvirus 2
Pseudo lumpy skin disease is in Aust but lumpy skin is not
Can a tick infestation cause hair loss?
Yes because it is extremely itchy and the cows rub up against and scratch on anything they can
What are the three most important ticks?
Ixodes holocyclus- paralysis tick
Haemaphysalis longicornis- bush tick
Rhipicephalus sanguineus- brown dog tick
What does buffalo fly affect in cows?
Reduced weight gain and lower milk yield which also means lower weight gain in suckling calves
Also carries a nematode
What will be seen in an infestation of buffalo flies?
Tail swishing, head shaking and rubbing of the shoulders and flanks
Should you try to prevent buffalo fly?
No, don’t try to use chemicals prophylactically, wait until you have a real problem and use different products so resistance doesn’t bulid up
Does Aust have a lot of lice sp?
One biting louse- bivicola
Two or three sucking louse
Spread by direct contact
What is chorioptic mange?
Thickening of skin at base of tail and diagnosed by skin scrapings
What are stephanofilaria?
Small nematodes that are carried by buffalo fly and live in a cyst at the base of a hair follicle
What is myiasis?
Blow fly that can blow living tissue being found in wounds
What are the signs of myiasis?
Irritation and signs of septicaemia later on
Are SCC common in cattle?
Yes in Herefords and Holstein fresians
Usually non-pigmented areas
What will you see with copper deficiency?
Coat colour lightens
‘Spectacles’ in angus cows
Fractures of long bones also associated
What will you see with cobalt deficiency?
Poor growth rate and wasting as well as fragile hairs
What will you see with zinc deficiency?
Loss of hair, thickened skin and MCJs
How does photosensitisation occur?
Primary- ingestion of photodynamic agent
Secondary- liver damage –> can no longer get rid of phytoporphyrin
Where are the most common lesions for photosensitisation?
Non-pigmented skin with small amount of hair and exposed to sunlight
What are some signs of photosensitisation?
Erythema, oedema, irritation, photophobia, shade seeking and standing in water
Can have intense pain
What are two plants that have been associated with secondary photosensitisation?
Green oats and turnips
What is swedes-induced hepatic photosensitisation?
Disease in NZ that not much is known about?
What significance dose pale knotweed and Prince’s feather have?
CAuses acute liver failure/necrosis leading to secondary photosensitisation after the plant is hot and dry for a period of time
How can you treat photosensitisation?
Identify and remove the hepatotoxin
Give shade and antihistamines if early in disease
