Skin Disease in Cattle (Farm Animal Dermatology

causes of skin disease

-ectoparasites

-bacteria

-fungi

-prions

-nutritional

-toxic

-stress

what symptom is common to all ectoparasites

pruritis

which is the other skin disease caue that also causes pruritis

what is the other clinical sign that you can differentiate it from ectoparasites

prion→ scrapie → also get neuro signs

dermatophytosis (ringworm) common in

-young calves and often self limiting

-can take few months to resolve

-animals suffering poor nutrition or immunosuppressed (BVD)

ringworm

transmission of ringworm

-zoonotic

survival of ringworm

survive in buildings for months so lesions often resolve once animals turned out

diagnosis of ringworm

clinical signs or microscopic evaluation of spores on hair plucks

treatment of ringworm

topical enilconazole

-vaccination discontinued (ringvac)

what causes ringworm

trichophyton verucosum

classification of insects

flies, lice ticks and mites common in fa

common mite

chorioptes on tail head, self limiting

rare cases of sarcoptic or psoroptic mange which are more severe

ticks an issue why

vector of tick borne fever and babesia

flies an issue why

vector for moraxella bovis and summer mastitis pathogens

what fly is notifibale in SCOTLAND

warble fly

ectoparasites of sheep

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• Psoroptes ovis (sheep scab mite) – Severe and contagious

• Myiasis (blowfly strike) – massive welfare concern

• Lice – Less severe than sheep scab but associated with debility and weight loss

• Ticks

• Head Flies – important for horned sheep

• Keds – uncommon and not a big issue

• Nasal Bots – uncommon, unpleasant when they do occur

what can ticks be a vector for in sheep

vector for Louping ill, S.aureus, TBF

sucking lice examples in cattle

-haematopinus

-linognathus

biting lice examples in cattle

damalina (bovicola)

look of lice

-on skin surface and easily seen by naked eye

-dark grey/brown colour and size of flattened pin head

-sucking lice= pointy head

-biting lice= round head

life cycle of lice

-eggs

-nymph

-adult

direct

epidemiology of lice

-very common

-usually winter due to increased coat thickness

-cannot survive off host

impact of lice

-decreased BCS/DLWG

-damaged skin/fleeces

-usually poor doers

diagnosis of lice infestation

visual inspection

lice infestation name

pediculosis

cattle lice species

bovicola bovi

haematopinus eurysternus

linognathus vituli

bovicola bovis

-most common louse

-chewing

-usually on head

linognathus vituli

-sucking louse

-around head area

-can lead to anaemia

haematopinus eurysternus

-sucking louse

-around horns

-can lead to anaemia

lice treatment

-pour on synthetuc pyrethroid like deltamethrin→ sucking and biting

-pour on group 3 ML anthelmintic like ivermectin→ sucking and biting

-injectable group 3 ML anthelmintic like ivermectin→ all sucking, little biting

issue with injectable group 3 macrocyclic lactone

removes all sucking but not all biting

what animals must be treated for lice and when

-all those in direct contact

-treat at start of winter housing period if cattle at risk

agent causing infectious bovine keratoconjunctivitis

bacterium moraxella bovis

vector for moraxella bovis

face fly

stage 1 of disease of infectious bovine keratoconjunctivitis (pinkeye)

-tearing

-lacrimation

-photophobia

-small central corneal ulcer

stage 2 of disease of infectious bovine keratoconjunctivitis (pinkeye)

-ulcer spreads across cornea

-cloudy cornea

-neurovascularisation

-pink cornea

stage 3 of disease of infectious bovine keratoconjunctivitis (pinkeye)

-ulcer spreads

-inner eye fills with fibrin deposition and loos yellow brown

stage 4 of disease of infectious bovine keratoconjunctivitis (pinkeye)

-ulcer covers entire cornea

-iris adhesions

treatment of infectious bovine keratoconjunctivitis

-antibiotics like oxytetracycline and amoxicillin

-give IM, SC, topical

-never give subconjunctival bc too hard

-NSAIDs

prevention of infectious bovine keratoconjunctivitis

-fly control with topical synthetic pyrethroid like permethrin

-biological control with parasitic wasps

onchocerca

-thin white worms found in eye of cattle

-not in UK

vectors of onchocerca

blackfly or cullicoides

ocular infection from onchocerca

-ranging from acute oedematous necrosis to chronic granulomatous changes

-results in marked fibrosis and mineralisation

treatment of onchocerca

-systemic ivermectin

-anti inflamms

warble fly

-hypoderma bovis

-hypoderma lineatum

life cycle of warble fly

-lay eggs on hair

-larvae hatch and migrate to oesophagus and spine where they overwinter

-in spring, back under skin to mature then drop off

-pupate in soil and a new warble fly is born

impact of warble fly

-gadding behaviour

-ectopic migration and paralysis

-damage caused by warbles

-downgrade of hide

-reduced repro

gadding behaviour from warble fly

flies cause harassment to cattle which become restless leading to injury and depressed leading to decreased production and growth

how does warble fly cause downgrade of hide

perforations of skin by breathing larvae

how does warble fly cause reduced repro

large numbers of warbles under skin in spring where cause stress and drains energy.

treatment of warble flies

organophosphate dips

-issue with safety and environmental contamination

-most effective in autumn

control of warble fly

-legislation to dress all obvious warble fly infested cattle

-since 1990 no more warble fly in UK

-eradicated but notifiable in scotland

-imported cattle must be treated on arrival

surface feeder mites

-chorioptes

-psoroptes

burrowing mites

-sarcoptes

-demodex

how does chorioptes look

-pedicles not joined

how does psoroptes look

-pedicles joined

-trumpet on end of legs

how does sarcoptes look

triangular scales

where is chorioptes found

-tail mange

-leg mange

-scrotal mange in tups → incrs temp → dcrs fertility

diagnosis of chorioptes

-deep skin scrapes from edge of lesion

-use sharp scalpel and scrape until capillary ooze

treatment of mites

Treatment is Permethrin (Synthetic pyrethroid)

or pour on Macrocyclic lactones (injectable less effective).

key to ticks

ixodes ricinus found where

-scotland

-wales

-north and south west england

-occ dorset and south east

ixodes ricinus

Haemaphysalis punctate

haemaphysalis punctate found where

Coastal areas of wales

tick life cycle

-larva hatch from egg and seek host

-engorged larva shelters in grass and moults to nymph

-nymph seeks host such as rabbit or dog

-engorged nymph shelters in grass and moults to adult

-adult female seeks host, engorges with blood and mates before dropping off

-engorged female lays eggs and dies

consequences of tick infestation

-poor BCS

-weight loss and reduced milk yields

-hide/fleece damage

-intense irritation

-lesions around bites like bacterial infection

-small granuloma formation in prolonged infestation due to retention of mouth parts

-hypersensitivity

-pass pathogens on

tick as vectors diseases

-tick borne encephalitis

-tick borne fever

-lyme disease

-q fever

-tick borne relapsing fever

-babesiosis

babesiosis and theileriosis

-protozoa similar to malaria and sleeping sickness

-parasite tha lives in RBCs of vertebrates

how is babesiosis and theileriosis spread

-transovarially→ through eggs

-transstadially→ across diff stages of life cycle

t annulata

tropical theileriosis

t parva

east coast fever

theileria mainly found

africa

-often local bovids have and it causes little disease but severe disease in domestic cattle esp european breeds

• beinging in naive animals → causes clinical signs to them

signs of theileriosis

-lymphadenopathy

-fever

-haemorrhage

-anorexia

-collapse

-pulmonary oedema

-dyspnoea

-death

babesia bovis spread by

rhipicephalus sp

babesia divergens spread by

ixodes ricinus

babesia signs

-pyrexia

-severe haemolytic anaemia

-haemoglobinuria

-death of infected animals

often known as red water fever in cattle

diagnosis of babesia and theileriosis

-history

-exam of skin for presence of ticks

-exam of skin scrape and/or sticky tape impressions for eggs or ticks

host control of ticks

-pour on pyrethroids or MLs→ not licensed in UK against ticks for cattle

• only work on stages where tick attached to host

• impact on GI worms→ resistant pressure

• needs to be reapplied at regular intervals

environmental control of ticks

-become active and start to feed in early spring

• start and duration hard to predict

avoid tick prone pastures

pasture improvement with drainage and scrub clearance

-cannot use ascaricide

-ensure immunity when young

photosensitisation

occurs when presence of chemical makes skin sensitive to sunlight esp UV

-skin damage and loss esp unpigmented areas

-can get slouhging and 2ndary infection

direct cause of photosensitisation

-chemical comes from defect in animals metabolism of RBCs

or more commonly from plants like st johns wort

secondary cause of photosensitisation

-animals with liver damage

-damage interferes with complete breakdown of chlorophyll resulting in accum of photosensitive chemical

local cause of photosensitivity

reaction to sap of some plants

most commonly affected sites of photosensitisation

parts exposed directly to sunlight inc udder (exposed when animal lies down)

signs of photosensitisation

-non pigmented skin affected

-hair loss

-reddening

-peeling

-ulceration of skin

-crusting

-bleeding

diagnosis of photosensitisation

based on clinical signs

treatment of photosensitisation

-removal to cool shaded housing

-fly control

-supportive therapy

prevention of photosensitisation

-do not breed from animals with this genetic defect

-identify and remove poss plant sources of photosensitising chemicals

nutritional causes of skin disease in camelids

• copper deficiency

• zinc responsive dermatosis (idiopathic hyperkeratosis)

copper deficiency in camelids

•Depigmentation of fibre and wire texture

clinical signs of cu deficiency in camelids

Poor growth and low immune tolerance

treatment of Cu deficiency in camelids

Require Cu supplementation (but avoid toxicity)

• but dont want to over supplement → get definitice diagnosis

zinc responsive dermatosis in camelids

Non pruritic papules with adherent crust

clinical signs of zinc responsive dermatosis in camelids

papules on Perineum, ventral abdomen, inguinal regions, axilla, medial thighs/forearms and face.

diagnosis of zinc responsive dermatosis in camelids

skin biopsy

treatment of zinc responsive dermatosis in camelids

•oral zinc sulphate/topical zinc shampoos. 

what is munge (severe dermatitis) in camelids

Adherent, hyperkeratotic crusts – paranasal/perioral regions

Idiopathic

how do you treat munge

treat secondary bacterial infection +/- ectoparasites.

ddx for munge

viral contagious pustular dermatitis,

dermatophilosis,

dermatophytosis,

bacterial dermatitis,

immune-mediated disease