Farm Animal Skin Disease Flashcards
What are the major chemical groups used for treatment of sheep, cattle and pigs?
Macrocyclic lactones
Synthetic pyrethroids
Organophosphates
Insect growth regulators
Give an example of a macrocyclic lactone
Ivermectin
Give examples of synthetic pyrethroids
Cis cypermethrin
Deltamethrin
Give an example of an organophosphate…
Diazinon
Give an example of an insect growth regulator…
Cyromazine
Why are organophosphates being phased out of use?
Effects on wildlife
What are the two lice of sheep and do they chew or suck?
Bovicola ovis - sucking
Linognathus ovillus - chewing
Why has the incidence of sheep body lice infestation in the UK increased recently?
Dipping has stopped
Outline the clinical signs associated with sheep body lice…
Severe fleece derangement
Rubbing/biting wool
Outline the epidemiology of the sheep body louse…
Numbers increase in long wool
Decline dramatically at shearing
Reduced by solar radiation
How are sheep body lice diagnosed?
Part of the wool and examine near skin
How are sheep body lice treatment?
Shearing
Insecticides
- Pour ons (deltamethrin)
- Saturation dip (organophosphates, synthetic pyrethroids)
List of mites of sheep…
Sarcoptes scabei Demodex ovis Psorobia ovis Chorioptes bovis Psoroptes ovis
What is sheep scab?
Psoroptic manage
Outline the clinical signs associated with psoroptic mange…
Pustules, then spreading moist lesions Matted fleece Extreme pruritus Mites just visible with naked eye Sheep may become thin and die
Outline the epidemiology of psoroptic mange…
Winter more favourable
Infections may be latent over summer
Mites can multiple rapidly
Outline techniques available for treatment and control of psoroptic mange…
Plunge dipping (organophosphate solution) Macrocyclic lactone injections
For how long may pastures, fences, buildings etc remain a source of psoroptes re-infection?
15 days
Why might plunge dipping not be effective for treatment of psoroptic mange?
Treatment times too short
Heads not dipped
Dip heavily fouled
Strength too low
What is blowfly strike?
Cutaneous myiasis
Outline the pathogenesis of blowfly strike…
Primary flies lay eggs in moist wool and inflamed skin
Larvae feed on the skin surface and cause extensive skin damage
Toxaemia due to skin necrosis and absorption of bacterial toxins
Subsequent invasion by secondary/tertiary flies
What are the predilection sites for blowfly strike?
Head (base of horns) Breech Prepuce Body Wounds
Outline the treatment for blowfly strike…
Clip surrounding area
Clean tissues and remove visible maggots
Apply insecticides
Supportive treatment indicated in severe cases
Outline the options available for prevention of blowfly strike…
Tail docking
Cyromazine
Dicyclanil
Cypermethrin
List the live of cattle
Bovicola bovis
Linognathus vituli
Haematopinus eurysternus
Solenopotes capillatus
How does chorioptes bovis cause infertility in rams?
Inflames scrotum leading to increased temperature
Outline the clinical signs of lice in cattle…
Number increase in cool months
Peak in early spring
Decline with coat shedding, solar radiation, and higher temperature
Most common in housed cattle
Outline diagnosis of lice in cattle…
Visible to the naked eye
Species distinguished by microscope
When is the best time to treat cattle for lice?
Autumn
Outline the treatments for lice in cattle…
Macrocyclic lactones
- Kills all sucking lice
- Reduces bovicola bovis
Others:
- Deltamethrin
- Cypermethrin
List the mites found in cattle…
Sarcoptes sabiei
Chorioptes bovis
Demodex bovis
Psoroptes ovis
Describe chorioptic mange in cattle…
Tail, hind legs, udder, perineum
Very common, mostly in housed cattle
Pruritic
Not severe
Describe sarcoptic mange in cattle…
Causes head and tail mange Mostly in housed cattle Any age affected Can be severe and acute Transmission by direct contact and fomites
How is sarcoptic mange in cattle diagnosed?
Clinical signs
Skin scraping
Skin biopsy
How is sarcoptic mange treated in cattle?
Macrocyclic lactones
Outline treatment for psoroptic mange in cattle…
Permethrin pour-on
Describe demodectic mange in cattle…
Common, but rarely diagnosed
More a problem for hide image
No pruritus, little hair loss
Occasionally develops into nodules and secondary infection
What is lumpy wool?
Dermatophilosis in sheep
In what species does dermatophilosis occur?
Sheep Camelids Goats Pigs Horses (Cattle)
Describe dermatophilosis
Produces crusts of varying thickness on wooled/haired skin
Lesions can be painful to lift off
Tends to follow wet weather
How is dermatophilosis diagnosed?
History
Clinical signs
Smears from scabs
How is dermatophilosis treated?
Remove animals from wet conditions Correct any underlying problems predisposing to infection Systemic ABs Topical treatment (Chlorhexidine)
What is ringworm?
Dermatophytosis
Describe ringworm
Focal patches of thick grey crust/scales with alopecia Particularly affects head and neck Pruritus variable Self-limiting Zoonotic
Outline treatment and control for ringworm..
Enilconazole
Vaccinations
