Sudden death in large animals Flashcards
Whats the first step when investigating a sudden death/s of a large animal?
- Get a good history which includes:
o Signalment (species, breed, age, sex)
o Location
o Available plant species
o Recent weather
o Recent movement
o Water sources e.g. blue-green algae
o Arrival of new animals? If so, source?
o Access to dumps/garbage – toxins
o Malice – issues with neighbours, poisoned by neighbour
o Diet and dietary changes
o Management changes
o Location of carcasses
o Clinical signs (of any other animals)
Are there any areas you wouldnt do a PM?
Areas accessible to animals
Areas which may contain food
High traffic areas
Areas difficult to disinfect
Where should you do a PM?
Concrete
Dirt area in the sun
Use a straw bed? - dispose of after PM
Are PMs in large animals done laterally?
Yes laterally is easiest in large animals?
What is a potential hazard of doing a PM in a large animal?
The ribs - they are large and can have sharp jagged edges once cut
How should microbiological samples be collected?
Microbiology specimens are collected aseptically
Sample intestine last
Collect generous tissue samples
Place fresh tissues in separate containers – don’t use formalin
Keep samples cold with ice/gel packs
Direct your sampling towards the most likely cause
Interpret results in light with clinical/gross findings
Should you fix tissue samples that are >1cm in diameter?
No, formulin doesnt penetrate more than 5mm so samples >1cm should not be used.
How should potentially zoonotic samples be packaged?
Double or triple bagged + PCR samples in ice
List some causes of sudden death in ruminants
- Acute infections
o Enterotoxaemia
o Blacks disease
o Blackleg
o Botulism
o Anthrax
o Babesia
o Salmonella
o Leptospirosis
o Shipping fever - Toxicities
o Snake bite
o Urea toxicity
o Monensin – used as a supplement but can be overdosed
o Organophosphates
o Lead
o Aflatoxins in feed, peanuts, grains, bread
o Plants
o Nitrate/nitrite e.g. sorghum
o Oxalates e.g. oxalis
o Cyanogenic glycosides e.g. sorghum
o Fluoroacetates e.g. Gastolobium
o Cardiac glycosides e.g. oleander
o Pyrrolizidine alkaloids e.g. Paterson’s curse
o Taxine diterpenoid alkaloids e.g. Yew trees
o Nicotene alkaloids - Other mishaps
o Electrocutions/lightning strikes
o Trauma
o Hardware disease caused by a foreign body causing a fibrous peritonitis
o Anaphylaxis e.g. after vaccination
o Heatstroke - Metabolic/nutritional disease
o Polioencephalomalacia
o Hypomagnesaemia
o Rumenal acidosis causes dysbiosis in rumen = less bacteria producing thiamine which is essential in the brain = thiamine deficiency polioencephalomalacia
o Bloat
o Milk fever
o Ketosis
What findings may you see with rumenal tympany or bloat in LA?
- Congestion of the tongue, cervical oesophagus (image on right) and lymph nodes of the head, neck and thorax due to pressure on thoracic cavity and impaired venous return
- Blanched thoracic oesophagus caudal to thoracic inlet (image on right)
- Creates a bloat line - defining characteristic of bloat (well demarcated line)
What is rumenal tympany or bloat?
o Overdistension of the rumen and reticulum with gases of fermentation either as foam or free gas. A common cause of sudden death in cattle
o Compressed lungs
o Rare in goats, sheep and deer
o Primary (or frothy) bloat
What might cause rumenal tympany or bloat?
- Dietary origin (legume pasture, increased grain)
- affected animals are typically found dead
Describe what we are seeing here.
- Polioencephalomalacia – vit B1 deficiency related to ruminal acidosis. See yellow discolouration of cortex, well demarcated area affecting grey matter (laminar necrosis)
- Under UV light, fluoresces if affected (brain on bottom)
Describe what we are seeing here.
- Clostridial diseases cause sudden death
- necrotising necrohemorrhagic myositis
- Seeing: necrosis, haemorrhage,
Describe what we are seeing here
- Haemorrhagic enteritis
Describe what we are seeing here
- ## Segmental Haemorrhagic enteritis caused by a clostridial agent of disease
Describe what we are seeing here
- Spiral colon is enlgarged and wet
- Not able to tell this is mesenteric torsion from the image alone.
Describe what we are seeing here
- Salmonella can cause 2 types of enteritis (haemorrhagic and fibrinonecrotic). In this case we are seeing a fibrinonecrotic entertis.
- There is a fibrinous deposit
Describe what we are seeing here
- Aortic rupture
- Sudden death in this instance = internal bleeding.
- Major vessel rupture, centre area of necrosis surrounded by pale tissue
Describe what we are seeing here
- Haemorragic and fibronecrotic enteritis - salmenellosis
- Serosa of the caecum is red (distal colon is also affected
Describe what we are seeing here
- Fibronous deposits
- fibronecrotic enteritis - salmenellosis
