Weight loss sheep Flashcards by Helen West

List 8 differentials for weight loss in sheep

Degenerative- lame, broken mouth
Neoplastic: OPA
Nutritional: dietary deficiencies
Infectious:
- Iceberg- Johne’s, MV, CLA, Borders disease
- parasitic
- Scab - Psorptes ovis
-Lice
Toxic: ingested plant toxins, copper toxicity

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what percentage lame sheep do we expect in a well managed flock

<2%

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what can drive lameness in sheep

outbreaks of footrot, contagious ovine digital dermatitis (CODD)
eryspiela and joint ill in lambs

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Describe lameness scoring in sheep

0= good or imperfect mobility
1= lame
2= severely lame

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Describe the 5 point plan to reduce lamness in sheep

cull
vaccinate
quarantine
treat
avoid

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what causes OPA

betaretrovirus called Jaagsiekte sheep retrovirus (JSRV)

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List the clinical signs of OPA

chronic wasting
progressive respiratory distress
appetite remains good
leads to death

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what happens in OPA

tumours grow in lungs and secrete fluid - both of these impair lung function

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Describe how to ultrasound helps diagnose OPA

Will see hyperechoic lesions
is currently the only widely used method to diagnose preclinical or subclinical OPA in live sheep

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What is MV caused by

lentivirus

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Describe how MV is spread

aerosol
vertical through colostrum and milk

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How is MV introduced to flock

always through introduced sheep

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What causes Caeseous Lymphadenitis

Corynebacterium pseudotuberculosis

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Why is caeseous lymphadenitis hard to get rid of

Lasts well in the environment

Up to 20 weeks in the corners of sheds in purulent material
Up to 8 weeks on organic fomites
24 hours in sheep dips

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when does Caeseous Lymphadenitis tend to spread

at shearing

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what does Caeseous Lymphadenitis cause

Superficial infection –>Lymph nodes –> suppurating infection –> haematological spread –> abscesses in internal organs

What causes border disease

pestivirus

what is borders disease similar to

BVD in cattle

what does borders disease cause

Abortions and still birth if infected early
hairy shaker- causes weird fleece and the lambs have clonic tonic contractions of skeletal muscle

Causes PIs if infected at appropriate times

T/F Johnes causes weight loss and scour in sheep

False doesn’t cause scour in sheep

How does Johnes affect albumin and globulin levels in sheep

low albumin
normal globulins (rarely low in severe disease)

Describe how Johnes in sheep spreads

faecal oral transmission
good environment stability
subclinical carriers

List 4 differentials of Johnes at flock level

poor nutrition
fasciolosis
chronic parasitism
virulent footrot

List 4 differentials of Johnes on individual sheep level

dentition
chronic septic focus
chronic severe lameness
OPA

Describe how to diagnose Johne's in sheep

Blood albumin: globulin ratio in 10 affected animals is most useful

Describe how to differentiate between johnes and liver fluke in sheep

look at albumin and globulin ratio Both low= liver fluke Albumin low- globulin normal= johnes

Describe how to treat johnes in sheep

no treatment

Describe what the problem with the johnes vaccine is in sheep

will reduce shedding but will not stop sheep getting infected

describe how to control johnes in sheep

same as in cattle culling positive sheep trying to prevent lambs from getting infected

How long does it take for liver fluke to produce eggs

8 weeks

when does acute liver fluke signs show

3 weeks after lots of immature fluke eaten will see massive fatal haemorrhage in liver

Describe the sub-acute signs of liver fluke in sheep

rapid loss of weight some weaker sheep recumbent mortality can be high but after a period of clinical signs

Describe the clinical signs seen with chronic liver fluke

very poor condition score - will decrease slowely bottle jaw may die in emaciated state at times of high metabolic demand

How can vaccinating for clostridia reduce mortaility of liver fluke

Naturally find clostridia spores in the liver so when liver damage occurs these can be released, can tipp the sheep over the edge

Describe how to diagnose liver fluke

faecal egg flotation fluke ELISA- better for young animals Hypoproteinaemia in blood PM

what do you see on PM with liver fluke

Acute- pale anaemic liver, not smooth, see tracts and poss necrosis Chronic- calcified bile ducts, possibly see adult flukes

Describe how to prevent liver fluke

stop the sheep shedding eggs - treat effectively during quarantine pasture management- stop sheep going into snail habitat

Describe how to treat liver fluke (quarentine dose)

Dose that kills everything Triclabendazole (is a benzimadazole) followed by closantel or nitroxynil is considered a good approach

What is important to consider about treating fluke

what stage of liver fluke you are targeting consider time of year- some more effective than others