Parasite skin diseases of cattle Flashcards
parasites infections of cattle of most concern to us
- Warbles
- Lice!
- Chorioptes!
- Sarcoptes
- Psoroptes
- Demodex
macrocyclic lactones for cattle and admin methods
- ivermectin > pour-on, injection
- doramectin > injection
- eprinomectin > pour-on, injection
ivermectin milk and meat withdrawl
POUR-ON
- milk withdrawl: 60 days
- meat withdrawl: 49 days
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INJECTABLE
- milk withdrawl: 60 days
- meat withdrawl: 35 days
doramectin milk and meat withdrawl
INJECTABLE
- milk withdrawl: 60 days
- meat withdrawl: 40 days
eprinomectin milk and meat withdrawl
POUR-ON
- milk withdrawl: 0 days
- meat withdrawl: 0 days
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INJECTABLE
- milk withdrawl: NA
- meat withdrawl: 120 days
hypoderma bovis and lineatum
- what are they?
- when do we see them?
- Hypoderma bovis (northern cattle grub)
- Hypoderma lineatum (common cattle grub, heel fly)
- used to be seen February-April in southern Ontario
- now very uncommon - more common < 2 years of age
hypoderma species cause what lesion? due to what part of their life cycle?
subcutaneous swellings = “warbles”
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- cutaneous perforation (1-2 months)
- larva emerges and pupates in ground (~5 weeks)
> hypoderma bovis, hypoderma lineatum
H. bovis
- how and where they lay eggs?
- winter resting site?
H. bovis
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eggs laid:
- singly
- lower / upper body
> hatch in a few days
- move winter resting site in epidural fat in spinal canal (late fall, stay for 2-4 months)
> migration to skin (feb-march)
H. lineatum
- how and where they lay eggs?
- winter resting site?
H. lineatum
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eggs laid:
- in rows
- legs / lower body
> hatch in a few days
- move winter resting site in esophageal submucosa (late fall, stay for 2-4 months)
> migration to skin (feb-march)
pathogenic significance of hypoderma
- Tissue damage > trimming
- Downgrading of hide/carcass
- Disturbance to cattle (“gad”)
* decreased milk yield and growth rate
hypoderma preventative therapy and timing
- after fly laying activity ceases BUT before larvae reach winter resting sites
- September to November in Ontario:
Use systemic insecticide: - all macrocyclic lactone formulations
!!!Don’t treat with macrocyclic lactone December to February!!!
adverse reaction following hypoderma treatment
when does it occur? what do we see?
(3 hours-3 days)
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1. Anaphylaxis-like reaction - rare
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2. Local inflammation
(a) vertebral canal syndrome (H. bovis):
- edema/inflammation > paresis, ataxia (b) esophageal syndrome (H. lineatum):
- edema/inflammation > dysphagia, drooling, bloat, metabolic acidosis
pediculosis in cattle - clinical signs
- low numbers = subclinical
- restless, scratching, licking
- rough coat / poor condition
- alopecia
- hide damage
- anemia (sucking lice – calves)
- decreased milk and growth rate
- nits/lice?
main biting louse of bovines? behaviour and anatomic locations?
- feed on exfoliated epithelium/ cutaneous debris
- very mobile
- Damalinia bovis - “cattle biting louse”
> poll, shoulder, back, rump, tail
main sucking lice of bovines? what do they feed on? what anatomic locations do they like best?
- feed on blood + tissue fluid
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(a) Linognathus vituli - “long nosed cattle louse”
– shoulder, back, rump, ribs, abdomen
(b) Solenopotes capillatus - “little blue cattle louse”
– muzzle, neck
(c) Haematopinus eurysternus - “shortnosed cattle louse”
– poll, neck, shoulder, back, tail head
pediculosis epidemiology, life cycle and seasonality
- confined to host
- eggs (“nits”) hatch in 5-14 days
- egg > adult = 3-6 weeks
- young cattle – more heavily infested
- breed in narrow temperature range
> seasonal periodicity: - very low numbers in summer
- breeding starts in fall
- heaviest infestation – winter/early spring
- apparent self-cure in spring
pediculosis treatment and control?
- if clinical, treat all animals in group at same time
- if short residual activity retreat in 14-16 days - not necessary with ivermectin pour-on as significant residual activity
- examine quality of nutrition
- single preventive treatment in fall / when housed for winter
- macrocyclic lactone pour-ons: biting + sucking lice
- macrocyclic lactone injectables: ONLY sucking lice
good pour-on options for pediculosis in lactating cattle? what is their residual activity?
- eprinomectin - Eprinex Pour-On
- permethrin - Boss Pour-On, Vetolice
- cyfluthrin - CyLence Pour-On
<><> - No residual activity for any of these (retreat in 14-16 days)
Beef cattle – additional compounds for lice aside from those used in dairy:
(a) Pour-ons:
* ivermectin
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(b) Injectables: (ONLY for sucking lice)
* ivermectin, doramectin
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(c) Back rubber - malathion
chorioptic mange of cattle
- how common?
- who gets it?
- lesions?
- dx
- signs
- commonest mange of cattle
- usually housed animals (dairy cattle)
- lesions - tail head, perineum > ?
- tend to remain localised
- allergic exudative dermatitis
- usually a few animals in group = clinical
- scrapings: large #s mites
- pruritus > economic impact ?
chorioptes bovis - epidemiology
- when do we see them? when dont we?
- signs?
- transmission?
- age?
- more active late winter/early spring
- generally disappears at pasture in summer
- infected animals commonly subclinical * summer persistence = pasterns ?
- transmission = direct contact + ?
- rare on animals < 6 months
chorioptes - preventative treatments, timing
- fall
- treat all/some cattle + clean environment ?
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1. Macrocyclic lactone pour-ons
2. Permethrin - Vetolice, Boss Pour-On > these are extra-label but have sero milk withdrawl
<><> - eradication from herd = problematic
sarcoptic mange in cattle
- pathogen
- how common?
- significance?
- site preference?
Sarcoptes scabiei var bovis
* uncommon
* potentially severe mange
* site preference of mite ?
– neck, brisket, inner thighs, root of tail > whole body
* zoonotic
Note: not reportable in USA or Canada
Sarcoptic mange - cattle
- clinical signs and impact
- red papules + erythema
- intense pruritus
- thickened skin, alopecia
- scabs on skin
…………V…………
(a) decreased milk yield, weight loss
(b) decreased growth rate
(c) downgrading of hide
sarcoptes life cycle, activity, transmission, who is susceptible
- life cycle = 10-14 days
- adult mites don’t survive > few days off host
- most active in cold, wet weather
- transmission mainly by direct contact ?
- poor condition = more susceptible
sarcoptes diagnosis
- large # deep skin scrapings
sarcoptes treatment
- All macrocyclic lactone formulations
- (a) clean/disinfect all pens
(b) leave building vacant + dry for 3 weeks
Psoroptic mange (Psoroptes ovis)
- how common
- site preference
- signs
- very uncommon
- site preference ?
– neck, withers, root of tail > generalised
– persistent intense pruritis
psoroptes epidemiology
- how they cause damage
- life cycle length
- transmission
- optimal environment
- piercing mouthparts > skin damage
- hypersensitivity to saliva/feces antigens
- life cycle = 10-20 days
- transmission = direct + indirect
- optimum condition = moist + cool temperature
Psoroptes Dx
- mites readily demonstrated in scrapings
Note: not reportable in USA or Canada
demodex bovis
- how common
- signs
- sites
- lesions
- who gets them?
- transmission
- uncommon ?
- usually subclinical
- papules/pustules (1-30 mm)
- brisket, lower neck, forearm, shoulder
- usually no alopecia/pruritus
- hair follicles/sebaceous glands distended – cheesy content
- nodules typically do not persist > 7 weeks
- typically adult dairy cattle – late winter, spring
- transmission = direct contact
