Brisket oedema & liver fluke Flashcards
1
Q
Ddx for oedema
A
- high altitude dz
- malignant oedema
- liver fluke
- Johne’s dz
- PGE
- other clostridial dz e.g. struck
- heart dz
- reduced venous return - udder oedema
- non-parasitic liver dz
2
Q
High altitude dz
A
- low saturation in the air
-> pulmonary hypertension
-> oedema in ventral tissues of chest and abdomen (ascites)
-> as well as oedema see pleural effusion and ascites with jugular pulses
-> exopthalmost
-> at PME may see right sided CHF and pulmonary hypertension - not in UK
- seen above 5000ft altitude
- Switzerland, USA (esp southern states), Mexico, Peru, China & Middle East , Middle & South Africa
3
Q
High altitude dz
A
- move to a lower altitude
- diuretics
- appetite stimulants (B vitamins)
- thoracocentesis is really helpful
- breed for more resistant stock
- don’t break from affected animals
4
Q
Malignant oedema - aetiology
A
- caused by clostridial dz
- clostridial dz tend to be contracted from ingested, often with soil contamination of feed
- often spread by dirty (soil) needles
- love low oxygen levels
- C. sordelli, septic, novae and chauveoi
- C. perfringens not considered significant in this case
5
Q
Malignant oedema CS
A
- Sudden death.
- Rapid multiplication deep in tissues so clinical signs in <48hrs
- Occasionally seen in animals without an overt trauma, and occasionally in groups which suggests may have latent spores which are activated by perhaps bruising
- All ages affected
- Anorexia, depression, fever, death. May have local swelling at source of infection
6
Q
Malignant oedema PM signs
A
- affected muscles are dry and friable, red/black, emphysematous
- pericardium similarly affected
- myocardial haemorrhage and necrosis
- fat on a muscle smear showing fluorescent rods
7
Q
Malignant oedema tx and prevention
A
- use clean needles
- Bravoxin:
– multivalent clostridial vaccine
– covers 10 different clostridia - clostridia responds well to penicillin but only work if catch it before they die (very short window))
- is injecting them and causing damage to the muscle which can allow it to spread better than leaving them?
8
Q
Udder oedema
A
- aetiology unclear
- total protein, calcium, phosphorus as well as high and low density lipoproteins all significantly decreased in cows with udder oedema
- correlation with reduced dry matter intake
- these results suggest that transient liver dysfunction, probably linked to feed ration deficient in dry matter may be involved
at or around calving:
- udder preparing for next lactation + increased weight on abdomen (increased pressure on vena cava) due to being pregnant
9
Q
Udder oedema tx and prevention
A
- diet during the dry period is most effective form of prevention
tx can be split into nursing care and medication
- massage and hot compress to stimulate circulation
- diuretics: frusemide at 1mg/kg 2x daily IV (Dimazon)
- corticosteroids once calved: 1mg/12.5kg IV or IM (Colvasone)
10
Q
Liver fluke
A
- trematodes
- fluke ingested as metacercaria
- migrate intestine -> peritoneum -> liver
- wanders around the liver to settle in the bile ducts
– 2d to liver
– 4-6w to bile duct
– 8w+ to eggs - matures and begins to lay eggs
11
Q
Liver fluke CS
A
- acute: 3w after lots of immature fluke are eaten by sheep, dying of blood loss at this point
- subacute: rapid loss of body condition and fleece quality. some sheep weaker and may be recumbent. mortality can be high, but after a period of CS. usually from December onwards, but can be earlier (October) with severe challenge
- chronic: v poor body condition, poor fleece quality, bottle jaw. may die in emaciated state at times of high metabolic demand. often later in season, high metabolic demand is around late pregnancy and early lactation
12
Q
Why does vaccinating against clostridia help reduce fluke mortality?
A
- damage is due to the fluke damaging the liver
- this damage causes massive bleeding and total loss of protein resulting in anaemia and death
13
Q
Liver fluke diagnosis
A
- Fluke egg counting is more time consuming than worm egg counting
- Requires faecal egg flotation
- Sometimes see rumen fluke (paramphistomes) eggs, but this is usually an incidental finding
- Blood samples may help guide – hypoproteinaemia
- Post mortem examination of the liver:
– acute: anaemic, damage obvious around the edges, entry points visible
– chronic: massive damage to bile ducts, adult fluke evident - PM rest of animal:
– in acute stage may see immature fluke in the abdomen, or tracks through peritoneum, haemorrhage
– in chronic and subacute may see wasting and some icterus
– bottle jaw and brisket oedema possible
14
Q
Liver fluke prevention
A
- Stop the sheep shedding eggs – either kill the parasite or the sheep – don’t buy it in – treat effectively during quarantine
- Stop the sheep ingesting the metacercaria – pasture management
- Stop the miracidium entering the snail – pasture management
15
Q
When will liver fluke be chronic vs acute?
A
Acute when there are migratory patterns of immature fluke – needs to be warm and wet and for the animals to have access to mud snails
Chronic when there has been slow exposure to fluke and those fluke have matured (8-12weeks), so more commonly seen at the end of a winter period
