Weight loss sheep

Question 1

List 8 differentials for weight loss in sheep

Answer 1

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

Question 2

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

Answer 2

<2%

Question 3

what can drive lameness in sheep

Answer 3

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

Question 4

Describe lameness scoring in sheep

Answer 4

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

Question 5

Describe the 5 point plan to reduce lamness in sheep

Answer 5

cull
vaccinate
quarantine
treat
avoid

Question 6

what causes OPA

Answer 6

betaretrovirus called Jaagsiekte sheep retrovirus (JSRV)

Question 7

List the clinical signs of OPA

Answer 7

chronic wasting
progressive respiratory distress
appetite remains good
leads to death

Question 8

what happens in OPA

Answer 8

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

Question 9

Describe how to ultrasound helps diagnose OPA

Answer 9

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

Question 10

What is MV caused by

Answer 10

lentivirus

Question 11

Describe how MV is spread

Answer 11

aerosol
vertical through colostrum and milk

Question 12

How is MV introduced to flock

Answer 12

always through introduced sheep

Question 13

What causes Caeseous Lymphadenitis

Answer 13

Corynebacterium pseudotuberculosis

Question 14

Why is caeseous lymphadenitis hard to get rid of

Answer 14

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

Question 15

when does Caeseous Lymphadenitis tend to spread

Answer 15

at shearing

Question 16

what does Caeseous Lymphadenitis cause

Answer 16

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

Question 17

What causes border disease

Answer 17

pestivirus

Question 18

what is borders disease similar to

Answer 18

BVD in cattle

Question 19

what does borders disease cause

Answer 19

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

Question 20

T/F Johnes causes weight loss and scour in sheep

Answer 20

False doesn’t cause scour in sheep

Question 21

How does Johnes affect albumin and globulin levels in sheep

Answer 21

low albumin
normal globulins (rarely low in severe disease)

Question 22

Describe how Johnes in sheep spreads

Answer 22

faecal oral transmission
good environment stability
subclinical carriers

Question 23

List 4 differentials of Johnes at flock level

Answer 23

poor nutrition
fasciolosis
chronic parasitism
virulent footrot

Question 24

List 4 differentials of Johnes on individual sheep level

Answer 24

dentition
chronic septic focus
chronic severe lameness
OPA

Question 25

Describe how to diagnose Johne’s in sheep

Answer 25

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

Question 26

Describe how to differentiate between johnes and liver fluke in sheep

Answer 26

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

Question 27

Describe how to treat johnes in sheep

Answer 27

no treatment

Question 28

Describe what the problem with the johnes vaccine is in sheep

Answer 28

will reduce shedding but will not stop sheep getting infected

Question 29

describe how to control johnes in sheep

Answer 29

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

Question 30

How long does it take for liver fluke to produce eggs

Answer 30

8 weeks

Question 31

when does acute liver fluke signs show

Answer 31

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

Question 32

Describe the sub-acute signs of liver fluke in sheep

Answer 32

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

Question 33

Describe the clinical signs seen with chronic liver fluke

Answer 33

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

Question 34

How can vaccinating for clostridia reduce mortaility of liver fluke

Answer 34

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

Question 35

Describe how to diagnose liver fluke

Answer 35

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

Question 36

what do you see on PM with liver fluke

Answer 36

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

Question 37

Describe how to prevent liver fluke

Answer 37

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

Question 38

Describe how to treat liver fluke (quarentine dose)

Answer 38

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

Question 39

What is important to consider about treating fluke

Answer 39

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