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Flashcards in Small Ruminant Parisitology Deck (35):
1

Name 3 anti-parasitic drugs licensed for sheep in canada

Ivermectin
Lasalocid
Sulphamethazine

2

Off-label anti-parasitic drugs

Fenbendazole • Decoquinate • Albendazole • (Monensin)

3

Diarrhea

A. Coccidiosis
B. Parasitic gastroenteritis

4

Pathogenic species in sheep (2)

2 pathogenic – E. crandallis, E. ovinoidalis

5

Pathogenic species in goats (many)

E. ninakohlyakimovae, E. caprina, E. arloingi, etc

6

Signalment for coccidiosis in sheep/goats
Clinical signs

very common
• 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)

7

Diagnosis for coccidiosis in sheep/goats

Clinical signs + fecal flotation – speciate ?

8

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)

9

Treatment for coccidia

Treatment – isolate clinically affected – fluid therapy?
- treat entire group with coccidiocide (sulfa, amprolium) - move to clean bedding/grazing

10

Coccidia prevention

• 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

11

3 most important gastrointestinal nematodes (all live in the abomasum). Which cause diarrhea

Teladorsagia (similar to ostertagia)
Trhichostrongylus
Haemonchus (largest) - no diarrhea

12

What causes sudden death?

Haemonchus
Fasciolosis

13

Haemonchus

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)

14

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

15

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)

16

What are the concerns with parasitic gastroenteritis w.r.t. drug resistance

globally – drug resistance in Teladorsagia and
Haemonchus = major concern:

17

Main things to remember

• ewes = primary source of pasture contamination in spring • prepatent period for important parasites = 3 weeks

18

Goals of drug programs

• minimize drug use
• minimize pasture contamination to end of June (“Targeted
deworming”)
• ideally, only treat animals that require treatment (reduces risk of selection for drug resistance)

19

Seasonal drug protocol for GI parasites

Autumn: Winter:
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!

20

Targetted GI parasite treatment

• Treat ewes at lambing if not treated in fall
• Monitor 4+ weeks after turnout
LSSC Ltd
• 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

21

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)

22

What type of lice is common in sheep?

Sheep - biting lice (damalina ovis)

23

What type of lice is common in goats?

Damalina caprae
Linognathus stenopsis

24

Clinical signs for lice

winter months
signs = pruritis, wool loss, decrease in weight, (anemia)
more severe if debilitated (malnutrition, GI parasitism)
Trasminitted through direct contact

25

Treatment for lice

Permetrhin, carbaryl
2 treatments 10-14 days apart if non-residual
injectable ivermectin (only for sucking lice)

26

Control for lice

shearing
preventative ttreatment in the fall
drug resistance - change drug class
quarentine treatment

27

Melophagus ovinus is what?

sheep ked

28

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)

29

Treatment for kieds

as for lice - shearing, permethrin, carbaryl, injectable ivermectin

30

Most common mange in cows & sheep?

chorioptic (tail head for cows, feet/scrotum for sheep)

31

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.

32

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

33

What is the nasal bot?

Oestrus ovis (nasal myiasis)

34

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
Clinical signs:
• 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
- season

35

Treatment for nasal bots (oestrus ovis)

IVermectin SC or PO
WInter treatment will kill over-wintering larvae