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Lent term fourth year > Parasitic diarrhoea and thin ewes > Flashcards

Parasitic diarrhoea and thin ewes Flashcards

1
Q

How much feed space should ewes have for continuous vs discontinuous feeding

A

Continuou s= 20cm
discontinuous = 45 cm

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2
Q

How high should grass swards be

A

> 4cm

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3
Q

What % BW do dry ewes eat per day vs lactating

A

Dry ewes = 1.5%
Lactating ewes = 3%

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4
Q

How does Johne’s disease work

A

Mycobacterium avium subspecies paratuberculosis ingested in early life
Enters M cells in Peyer’s patches –> granulomatous inflammation –> latent period –> diffuse, severe granulomatous enteritis

Get death in sheep 2-6 years old

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5
Q

What response causes paucibacillary vs multibacillary form of Johne’s disease

A

Pauci = mainly Th1
Multi = Th2

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6
Q

Symptoms of Johne’s disease in sheep

A

WEight loss, faecal softening, high egg counts
NO DIARRHOEA
Enlarged mesenteric LNs

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7
Q

Vaccination for Johne’s disease

A

Killed vaccine can be given from 3 weeks age
- NOT sterile immunity; but decreases shedding and slows disease course

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8
Q

Small ruminant lentiviruses pathogenesis

A

Not oncogenic
HAve tropism for macrophages and denditic cells; infiltration into organs
In lungs: see progressive pneumonia
In udder: progressive mastitis
In CNS: meningoencephalitis (VIsna)

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9
Q

How does Maedi virus work

A

= lentivirus; so macrphage/dendritic cell tropism
See hard udder with no milk, exercise intolerance and on PM lungs are heavy and rubbery + don’t collapse

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10
Q

What is CAE in goats

A

Caprine arthritis encephalitis
= Lentivirus
Causes encephalitis and arthritis

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11
Q

How to deal with Maedi-Visna

A

Can be part of accreditation scheme; test all animals twice over a year to qualify
- Then a proportion every few years + keep isolated stock

Control: keeping a young flock helps; spread sheep out to reduce horizontal transmission

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12
Q

What is Jaagsiekte retrovirus

A

= oncogenic retrocirus that affects sheep and causes transformation of type II pneumocytes

> Virus inhaled/ingested –> WBCs –> via blood to lungs –> type II pneumocytes
Get adenocarcinomas

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13
Q

Clinical signs/PM findings with ovine pulmonary adenocarcinoma

A

Exercise intolerace, increased resp rate/effort, weight loss

On PM: consolidated areas of lungs, often grey/purple, secondary infections

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14
Q

Offspring from which age age sheep do we want to keep when controling ovine pulmonary adenocarcinoma

A

OLDER ones; if still no clinical signs, probably don’t have it
-> So offspring will be free

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15
Q

What bacteria causes caseous lymphadenitis in sheep

A

Corynebacterium pseudotuberculosis = gram + rods
>

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16
Q

Pathogenesis of caseous lymphadenitis

A

Bacteria enters via skin lesions, reaches local LN and causes cycles of necrosis and encapsulation (via phospholiapse D)

Then get haematogenous spread to other LNs and lungs

> NB eosinophil entry causes green colour

Onion skin lesions

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17
Q

What disease is described as causing onion skin lesions

A

Caseous lymphadenitis; from corynebacterium pseudotuberculosis

18
Q

What drugs work against what stage liver fluke

A

Adults only: albendazole
Intermediate: closantel
Immature: triclabendazole

19
Q

Symptoms of chronic fasciolosis

A

Weight loss, pallor, submandibular oedema

20
Q

How does trichostrongylus affect trace element uptake

A

Decreased absorption of calcium and phosphate

21
Q

WHat is the benefit of ensuring good protein intake in ewes in relation to PGE

A

More protein allows ewes to maintain own immunity as well as growing lambs/milk
- SO helps avoid PRR (periparturient rise in faecal egg goings)

22
Q

Vaccinating for PGE?

A

There is a Haemonchus vaccine used lots in Australia

23
Q

Who is more haemonchus resistant out of texels and suffolks

A

Texels

24
Q

Which bioactive forages can reduce worm fecundity in sheep

A

Chicory, sainfoin…
Probably work via condensed tannins

25
Q

What is the use of nematophagous fungi in parasite control

A

e.g duddingtonia flagrans
- Fungus grows in dung and eats worm larvae
BUT must continue to administer fungal spores in diet

26
Q

What does resilience mean

A

Capacity to maintain production in the face of challenge

27
Q

What does tolerance mean

A

Ability to have no signs of disease despite relatively high FEC/parasite burden

= an acquired characteristic

28
Q

How do select for resilient sheep

A

Select for lack of secondary impacts of worm infection

e.g good growth rates, least pallor, least faecal soiling
OR least amount of treatment needed for these impacts

29
Q

what is a white drench i.e group 1

A

Benzimidazoles

30
Q

what is a yellow drench i.e group 2

A

Levamisole

31
Q

what is a clear drench i.e group 3

A

Macrocyclic lactone

32
Q

what is an orange drench i.e group 4

A

Amino-acetic nitriles

33
Q

What are purple drench i.e group 5

A

Spiroindoles

34
Q

Checking for resistance to anthelmintic drench

A

Do drench test
> Submit faecal samples from 6-10 treated animals after treatment to check that FEC = 0

For levamisole: 7-10 days post treatment
For benzibidazoles/macrocyclic lactones = 10-14 days

35
Q

Risk factors for development of AMR

A

Frequent dosing or long acting products

Lack of unexposed worms (in refugia population)

Under dosing; allows heterozygotes to survive
- Should dose to the heaviest in the group

36
Q

How can we improve the drug availability of wormers

A

Ensure correct drenching technique so it ends up in rumen

Starve animals for 24 hours before

37
Q

4 SCOPS principles

A
  1. Make sure any treatment given is fully effective
  2. Use management options where possible to reduce reliance on anthelmintics
  3. Use robust quarantine to avoid bringing in resistant worms
  4. minimise selection for worms that are resistant
38
Q

How can we do selective/targeted treatment of ewes and lambs to reduce amount of anthelmintics used

A
  • Randomly pick 6-10 lambs and do FECs to see if animals need worming
  • do same pre-lambing to see if need to treat ewes
  • can just treat twin/triplet bearing ewes s as they shed 70-90% more eggs than singles
    + ewe lambs shed more than older ewes
39
Q

In which GI parasite is benzimidazole resistant widespread and in which isn’t it

A

Lots of resistance in Teladorsagia
Nematodirus battus still susceptible
-> SO can be used as a selective treatment against N Battus since won’t make situation any worse in Teladorsagia

40
Q

What is a good quarantine procedure to stop introduction of resistant worms

A

Worm new stock with BEST WORMER e.g monepantel or derquantel
Then house or keep in yard for 48 hours so eggs are passed
- THEN turn out onto DIRTY pasture i.e where there is large in refugia population; helps dilute the genes

41
Q

What is a break drench

A

Remove everything in animal by using new drench
Then allow reinfection via contaminated pasture
- Idea is that mis-use of anthelmintics i.e where interval b/w treatments < worm lifespan
can lead to MORE resistant population within host vs on pasture

Lent term fourth year (38 decks)

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