Sheep Flashcards
Gi nematodes in sheep
Same broad principles apply as with cattle
Younger animals, pasture transmission
Clinical disease is more common and widespread
Anthelmintic resistance a huge global problem
PGE- mixed infection of multiple species
Chronic diarrhoea, poor growth, anorexia, 2* fly strike
Main solo player is Haemonchorus contortus
Causes sever, even fatal anemia; resistant
What is the barder pole worm
Typical trichostrogylid life cycle
Cause of disease in western canada (breeding ewes and lambs)
How do you diagnose barber pole worms
Clinical signs (esp, lambs <6mos)
Hyperacute: sudden death due to haemorrhagic anaemia
Acute: anemia, bottle jaw, ascites, dark faeces, anorexia
Chronic: weight loss, weakness, anorexia
Don’t usually see diarrhoea
FEC can be low (PPP) or high (1 000-20 000 EPG)
Definitive dx
L3 coproculture, PCR, or adults necropsy
FAMACHA score
Control of trichostrongyles and other GI nematodes in sheep
Maximize overall health
Pasture management
Breed resistant hosts
Strategic treatments
Spring and fall for all animals
Treat young animals 6-8 wks into grazing season
Targeted selective treatment
Only treat animals with a high FAMACHA or FEC
What is the lungworm in sheep
Dictyocaulus filaria
Essentially similar to D.viviparus in cattle, though less pathogenic in sheep
Anteriero cone on first-stage larvae in feces (Baermann)
Life cycle of Dictyocaulus filaria
PPP 3-4 weeks
First stage larvae in feces
Grow to 3rd stage in environment
takes ~1week
Ingested L3
Tracheal migration to lungs
Intestinal cestodes in sheep
Moniezia spp. And Thysanosioma spp.
Anoplicephalidae
Indirect life cycle, involving mite IH with cysticercoid
More pathogenic in lambs than cattle (diarrhoea, wt loss)
Tx: praziquantel
How are larval tapeworm transmitted
Cysterceri in tissue of sheep is ingested by DH
Eggs in feces are ingested by sheep
How do you diagnose taenia ovis
No clinical signs are associated with adult stages in dogs or cysticerci in sheep
At post mortem, cysticerci in skeletal muscle and heart lead to carcass condemnation (not zoonotic)
A cause of concern for sheep procedures in western canada
How do you control taenia ovis
No treatment for sheep
Treat dogs with praziquantel AT LEAST twice per year
Prevent dogs from eating infected sheep carcasses
Preventing dogs (and coyotes?) from accessing sheep feed
F.hepatica causes what in sheep
Normal DH
Acute fasciolosis
Migration of juvenile flukes ingested in short time span
Liver damage and haemorrhage
Sudden death, anemia, ascites, dyspnea, abnormal pain occurring 2-6 wk after infection
F.magna causes what in sheep
Aberrant DH
Non Patent infections
Flukes continue to migrate around the liver and cause significant damage
Aberrant hosts usually die within a few months of infection
How do you control flukes in sheep
In problem herds (herd level diagnosis), prevention
Avoid known contaminated pastures
Prevent livestock access to wetlands, cervid access to pasture
Control involves
Treatment of all exposed ruminants on farm
Closantel or triclabendazole in fall (resistance) to kill juvenile flukes, albendazole in early winter (kills adult)
What mites are common in sheep and waht do they cause
Chorioptes
Chorioptic mange is an occasional disease in sheep in canada
Lesions most common on feet and legs– pruritus, hair loss, exudation
Trumpets on short, unjointed stalks
What are keds
(dipetra)
Melophagus ovinus
Life cycle of keds
Adults on host - suck blood
larviparous
larvae on host
pupae on host
life cycle takes 4-5 weeks
Diagnosis of Melophagus ovinus
Clinical signs: none to general pruritus
Lamost every flock will have this
Direct inspection of fleece for adults and pupae
Control of Melophagus ovinus
Pour on pyrethroids (pupae resistant)
Dips
Shearing
Keds are not zoonotic
What is the nasal bot of sheep
Oestrus ovis
Life cycle of Oestrus ovis
Larvae migrate in nasal cahmbers and then sinuses
L3 sneezed out
Pupae
adult flies
larvae (L1) laid in nose
myiasis/fly strike in sheep is
The invasion of animal tissue by the larvae of dipterans (flies)
Obligate means
Hosts for larval development must be live
Facultative means
Hosts for larval development can be live or dead and larvae can also develop in organic matter
Prevention of myiasis– fly strike happens when and how to prevent
Worst season is summer
Frequent examination
In sheep, fly strike most often affects the region below the anus and between the hind legs
Seharing
Tail docking
Wound care
Manage diarrhoea from PGE
Breed selection
Apicomplexa of sheep coccidia
Eimeria spp
Toxoplasma gondii
Eimeria spp in sheep are
Includes both pathogenic and nonpathogenic species
Clinical features very similar to cattle
Toxoplasma gondii in sheep can cause ad dx
Toxoplasma in an important pathogen in sheep and goats, causing abortion, stillbirth, and/or neonatal disease in ewes infected for first time
How do sheep become infected
Outcome depends on when exposed in gestation
Dx: serology, IHC and PCR on abortus
Control of toxoplasma gondii in sheep
Regional variation in seroprevalence in sheep (20-100%)
In sheep
Prevent access of cats to feed
To prevent zoonotic transmission
After handling aborted or stillborn foetuses, thorough hand washing
Cook lamb and mutation to 70C or freeze at -20C for at least 3 days
