Cattle Parasitology Flashcards
1
Q
What are the cattle nematodes? Abomasum, SI, LI?
A
- Abomasum = Haemonchus contortus, Ostertagia ostertagi, Trichostrongylus axei
- SI = Trichostrongylus colubriformis, Nematodirus helvetianus, Cooperia oncophora
- LI = Oesophagostomum radiatum, Bunostomum phlebotomum, Chabertia ovina, Trichuris spp
2
Q
How does ostertagia cause damage?
A
- Abomasal wall damage
- raised pH of gastric juice from 2 to 7
- Poorer digestion + bacterial overgrowth
3
Q
How does cooperia cause damage?
A
- Damage to intestinal mucosa
- Impaired absorption
4
Q
How is PGE diagnosed?
A
- Grazing history & signalment
- Clinical signs and seasonality
- Plasma pepsinogen- ostertagiosis
- Faecal egg counts = Standard McMaster’s salt flotation
- Post mortem
- Antibody ELISAs = Indicate exposure rather than infection
5
Q
When is PGE highest on pasture?
A
Summer time - July
6
Q
What are the differences in epidemiology between gastrointestinal worms and lungworms?
A
- PGE =
- Gut worms are ubiquitous
- Gut worm larvae survive for months at pasture
- Progressive pasture infectivity builds over time
- Consistent, predictable annual disease pattern
- Lungworms =
- Lungworm infection not present on all farms
- Lungworm Survival on pasture is short
- Most important source of infection year to year
are carrier animals - Pasture infectivity build-up can be very fast
- Disease risk varies and is difficult to predict
7
Q
What are at risk animals of lungworms?
A
- Youngstock - 1st / 2nd grazing seasons
- Bought in cattle - from naive herds
8
Q
What is the pathology and clinical presentation of lungworms?
A
- Prepatent phase = L4 larvae in alveoli, migrate towards
bronchi = Alveolitis, bronchiolitis, bronchitis - Patent phase (26 days+) = Adult worms in larger airways,
eggs and L1 larvae in the alveoli = - Obstructive bronchitis
- Aspiration pneumonia
- Secondary bacterial infections
- Pyrexia –associated with secondary bacterial infections
- Animals may never fully recover from clinical disease =
- Ongoing losses in milk production ~£100/cow
- Including treatment costs, fertility etc. ~£140/cow
9
Q
What are CS of mild lungworm?
A
Intermittent cough when exercised
10
Q
What are signs of moderate lungworm?
A
- Frequent cough at rest
- Laboured breathing
- Squeaks crackles on auscultation
11
Q
What are signs of severe lungworm?
A
- Severe tachypnoea
- Dyspnoea
- ‘Air Hunger Position’
- Mouth breathing
- Deep harsh cough
- Salivation, anorexia
- Death
12
Q
How is lungworm diagnosed?
A
- Signalment, history & clinical signs
- Post-mortem
- Oviviparous parasite- live L1 larvae passed in faeces =
- Patent infection >26 days = Baerman technique
- Antibody ELISAs = Serum or milk sample
13
Q
What is acute disease of fluke?
A
- 2-6 weeks post-infection
- Juvenile flukes migrating through liver parenchyma
- Tissue damage + haemorrhage
- Uncommon in cattle
14
Q
What is chronic disease of fluke?
A
- 10-12weeks post-infection
- Adult flukes within bile ducts
- Chronic anaemia, hypoalbuminaemia (bottle jaw)
- Weight loss + poor BCS
15
Q
How is fluke infection diagnosed?
A
- Signalment, history & clinical signs - Tricky in adult cattle/ subclinical infections
- Serum biochemistry = Serum albumen, GLDH & GGT
- Fluke egg sedimentation = Individual or composite samples
- Copro-antigen ELISA = Theoretically more sensitive (4 weeks+)
- Antibody ELISA = 2-4 weeks post-infection
- Post mortem/Abattoir feedback
16
Q
How can parasites be controlled?
A
- Plan strategy in advance - control plan
- At-risk animals
- Performance testing - growth rates, egg count
- Lungworm + Fluke - history of disease + where on farm
- Pasture management - move to safe pastures
- Lungworm vaccine
- Limit reliance on anthelmintics
- Quarantine
17
Q
What is strategic dosing?
A
- Dosing to keep pasture contamination low =
- dose at 3,8,13 weeks after turnout with ivermectin as kills all worms (3 wks life cycle) + has 14 days residual activity
- doramectin = 5wk residual activity = dose every 8 weeks (+3 wks post turnout)
18
Q
What is therapeutic dosing?
A
- Monitor weight-gain + WECs
- Consider grazing strategy through year
- Difficult ton do. but more sustainable
- Tx at housing
19
Q
What should be done if lungworm on farm?
A
- Vaccinate = 2 doses 4 wks apart + 2nd dose 2 wks before turnout (Calves >8wks old)
- treat all animals in affected group
- Move clinically affected animals to safe pastures / house
- Check for secondary infections
- MILK WITHDRAWAL
20
Q
What are the 5Rs to reduce resistance?
A
- Right product for type of worm
- Right animal
- Right time
- Right dose rate
- Administered in right way
21
Q
What does cryptosporidum affect? CS? Dx?
A
- Young calves = 14-21days
- Diarrhoea + dehydration
- Dx = Hx + CS, faecal smear (ziehl-neelsen), antigen strips
22
Q
Tx + control of crypto?
A
- Good hygiene = disinfection of pens+ feeding equipment
- Reduce stocking density
- Halofuginone - prophylaxis (24-48hr of age)
- Supportive tx - IVFT
23
Q
What cocci affect cattle? CS? Dx?
A
- Young calves affected = 3-4wks post-weaning
- Eimeria zuernii + Eimeria bovis
- CS = Bloody diarrhoea + tenesmus, Chronic wasting / poor appetite
- Dx = Hx + CS, PM, Histopath
24
Q
Tx + control of cocci?
A
- Reduce environmental contamination = all in all out
- Prophylaxis = Decoquinate in feed / toltrazuril or dicazuril
- Tx = toltrazuril / diclazuril
- Supportive Tx
25
How is Neospora prevented / controlled?
* Closed herd
* Disposal of cattle tissues from calving / aborted fetuses
* Prevent dogs from accessing calving areas, cattle feed or grazing fields
* Serum antibody testing
26
What are disease vectors of flies in cattle?
* Hydrotea irritans = summer mastitis (trueperella pyogenes)
* Muscidae = New forest eye (IBK)
* Cullicoides = BTV, Schmallenberg
27
How can nuisance flies be controlled?
* Spot on / pour on SPs
* Tail bands / ear tags
* Pasture management + breeding habitat = topping
* Mitigation of risk = stockholm tar, bluetongue vaccine
28
What ectoparasites affect cattle?
* Lice = Bovicola (chewing) + Linognathus (sucking)
* Mites = Chorioptes bovis, Psoroptes bovis, Sarcoptes scabei
* Ticks = Ixodes ricinus - babesiosis, anaplasmosis, louping-ill
29
How are ectoparasites diagnosed, treated + controlled?
* Dx = lesion patterns, microscopy, skin scrapes....
* Tx = synthetic pyrethroids - pour on / spot on for LICE
= MLs pour-on / injectable for LICE + MITES (+ ostertagia L4)
- pour-ons for chewing lice
- injectables for sucking lice
30
What are signs of Babesia divirgens? Tx?
* Pyrexia + anaemia w hammer heart
* Pipe stem diarrhoea followed by constipation
* Port coloured urine (redwater)
* Tx = Imidocarb
31
What is the rumen fluke?
* Calicophoron daubneyi
32
How would you treat fluke?
* Juvenile = Triclabendazole
* Adult = Triclabendazole, Closantel
* Rumen fluke = Oxyclozanide
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