Weight loss sheep Flashcards
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
what percentage lame sheep do we expect in a well managed flock
<2%
what can drive lameness in sheep
outbreaks of footrot, contagious ovine digital dermatitis (CODD)
eryspiela and joint ill in lambs
Describe lameness scoring in sheep
0= good or imperfect mobility
1= lame
2= severely lame
Describe the 5 point plan to reduce lamness in sheep
cull
vaccinate
quarantine
treat
avoid
what causes OPA
betaretrovirus called Jaagsiekte sheep retrovirus (JSRV)
List the clinical signs of OPA
chronic wasting
progressive respiratory distress
appetite remains good
leads to death
what happens in OPA
tumours grow in lungs and secrete fluid - both of these impair lung function
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
What is MV caused by
lentivirus
Describe how MV is spread
aerosol
vertical through colostrum and milk
How is MV introduced to flock
always through introduced sheep
What causes Caeseous Lymphadenitis
Corynebacterium pseudotuberculosis
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
when does Caeseous Lymphadenitis tend to spread
at shearing
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
