Flashcards in Small Ruminant Parisitology Deck (35):
Name 3 anti-parasitic drugs licensed for sheep in canada
Off-label anti-parasitic drugs
Fenbendazole • Decoquinate • Albendazole • (Monensin)
B. Parasitic gastroenteritis
Pathogenic species in sheep (2)
2 pathogenic – E. crandallis, E. ovinoidalis
Pathogenic species in goats (many)
E. ninakohlyakimovae, E. caprina, E. arloingi, etc
Signalment for coccidiosis in sheep/goats
• typically lambs/kids @ 1-4 months of age
• usually poor growth, often pasty/diarrheic feces, dullness, abdominal pain, occasionally bloody diarrhea
• pot bellied, open fleeced
• subclinical infections → production impact
• often other diseases (e.g. pneumonia, urolithiasis)
Diagnosis for coccidiosis in sheep/goats
Clinical signs + fecal flotation – speciate ?
coccidia oocysts in the environment - how do they get there?
(a) oocysts may overwinter in environment
(b) ewes shed small #s oocysts in periparturient period
→ subclinical infections in early lambs → ?
• intensification ↑ likelihood of clinical coccidiosis
outdoors + indoors
• stress → disease (e.g. dietary change, weaning, shipping)
Treatment for coccidia
Treatment – isolate clinically affected – fluid therapy?
- treat entire group with coccidiocide (sulfa, amprolium) - move to clean bedding/grazing
• good hygiene in barns – clean bedding, dry, feed off ground
• house/graze late lambs in different areas from early lambs
• coccidiostat in lamb creep feed until 90 days old or until market - lasalocid, decoquinate, monensin (!)
- correct dose ?
• if no creep feed – script decoquinate or lasalocid into mineral/salt mix
• coccidiostat to ewes for 30 days prepartum ? - lasalocid, decoquinate
3 most important gastrointestinal nematodes (all live in the abomasum). Which cause diarrhea
Teladorsagia (similar to ostertagia)
Haemonchus (largest) - no diarrhea
What causes sudden death?
Sheep + goats – Haemonchus contortus (barber pole worm) Acute disease – sudden death, severe anemia
- lethargy, no diarrhea
Chronic disease – edema, weight loss, poor growth, anemia
Highest pasture L3 levels - late summer (July/August) Losses - lambs, yearlings (+/- adult sheep)
Haemonchus - Diagnosis & PM
Diagnosis – anemia, hypoproteinemia,
- often high gastro-intestinal nematode (GIN) egg counts
PM – hyperemic abomasal mucosa + parasite #s 1 parasite = 50μl blood loss/day
What is the immunity status of ewes w.r.t. gastroenteritis? lambs?
ewes = significant source of pasture contamination in spring (“peri-parturient relaxation of immunity”: 2-4 weeks before
lambing to 4-8 weeks after lambing)
primarily lambs mid summer onwards (+/- older animals)
What are the concerns with parasitic gastroenteritis w.r.t. drug resistance
globally – drug resistance in Teladorsagia and
Haemonchus = major concern:
Main things to remember
• ewes = primary source of pasture contamination in spring • prepatent period for important parasites = 3 weeks
Goals of drug programs
• minimize drug use
• minimize pasture contamination to end of June (“Targeted
• ideally, only treat animals that require treatment (reduces risk of selection for drug resistance)
Seasonal drug protocol for GI parasites
Deworm at housing with drug that kills adults & larvae
Winter: Sheep overwinter with few larvae and adults
Spring: On pasture, sheep eat infective L3. From infection to egg laying takes 21 days
Summer: Worming prevents pasture
contamination. Naive lambs produce most eggs so must be dewormed!
Targetted GI parasite treatment
• Treat ewes at lambing if not treated in fall
• Monitor 4+ weeks after turnout
• Monitor lambs at 4+ weeks after turnout and treat accordingly (if not possible, treat at 4 weeks and 8 weeks after turnout)
If control periparturient rise in ewe egg output – not usually necessary to dose lambs until weaning
• Treat in fall, at housing
MONITOR LAMBS IN JULY
What is the famacha guide?
Looks for anemia by looking at the eyes and only treating those with red conjunctiva. It is only applicable in areas with only haemonchus (useful in the south)
What type of lice is common in sheep?
Sheep - biting lice (damalina ovis)
What type of lice is common in goats?
Clinical signs for lice
signs = pruritis, wool loss, decrease in weight, (anemia)
more severe if debilitated (malnutrition, GI parasitism)
Trasminitted through direct contact
Treatment for lice
2 treatments 10-14 days apart if non-residual
injectable ivermectin (only for sucking lice)
Control for lice
preventative ttreatment in the fall
drug resistance - change drug class
Melophagus ovinus is what?
Melophagus ovinus is found when? life cycle is where/how long? tramsnission? what does it look like?
• winter months, poor condition
• entire 6-week life cycle on sheep/goats • transmission – direct contact
• pruritus, stained wool → fleece damage, anemia, odour, ↓ value
• shearing – removes larvae + pupae
hot climate – kills keds (remain ventral neck, breech)
Treatment for kieds
as for lice - shearing, permethrin, carbaryl, injectable ivermectin
Most common mange in cows & sheep?
chorioptic (tail head for cows, feet/scrotum for sheep)
Clinical signs for chorioptic mange? Peak season?
Alopecia, erythema, crusts, pruritis - wooless areas
- sheep scrotum, distal limbs
- goats - lower limbs, abdomen, hindquarters
- restless, chew on feet
- temporary infertility in rams?
- chorioptes ovis - host specific, peak in winter months.
Chorioptic mange - transmission?
Transmission - direct contact
live off host for a few days
Life cycle = 2-3 weeks
Diagnosis: skin scrapings at the edge of the lesions
Treatment: permetrhin pour on , repeat 10 days (ivermectin doesn't work well)
Note psoroptic manage is very uncommon in Canada & notifiable
What is the nasal bot?
Oestrus ovis (nasal myiasis)
How do sheep get infected by nasal bots
fly deposits larvae around/in nostrils in fluid → dorsal turbinates, sinuses (weeks – months) → pupate in ground (in spring)
• initial infestation → no signs
• subsequent infections → hypersensitivity
• fly → head shaking, nose rubbing, feet stomping
• larvae → rhinitis, sneezing, mucopurulent nasal discharge • production losses ?
Goats – usually milder clinical signs than sheep - usually with infected sheep
Diagnosis – nasal discharge – numerous eosinophils + mast cells