ESSENTIAL Samples
These are your non-negotiables — collect them in nearly every case of suspected toxicosis.
Rumen Contents
- Amount: Gallon bag mixed from different compartments
- Container: Clean, leak-proof plastic container (NO additives)
- Storage: Refrigerate or freeze ASAP
- Why it matters: Primary exposure site for many toxins—contaminated feed, plants, heavy metals, etc. Snapshot of recent intake.
Liver
- Amount: 1 pound
- Container: Plastic bag
- Storage: Freeze
- Why it matters: Metabolizes and can bioaccumulate toxins, first-pass metabolism means liver often has highest concentrations following oral exposure. Include formalin-fixed sample for histopathology.
Kidney
- Amount: One whole kidney (or sections from both)
- Container: Plastic bag
- Storage: Freeze
- Why it matters: Often contains the highest concentrations following IV exposure, also main route of excretion. Many toxicants can cause microscopic lesions here so include sections fixed in formalin.
Ocular Fluid
- Amount: 1–2 mL
- Container: Red-top or plain tube (no additives)
- Storage: Refrigerate
- Why it matters: Blood degrades quickly, ocular fluid is more stable postmortem. Ideal for nitrate, ammonia, electrolytes. Subject to postmortem change especially if left in the globe.
Feed and Water Samples
- Amount: Gallon bag, 16 oz water
- When mixed rations are suspected, include samples of mix as delivered and individual components
- Container: Clean plastic bags or bottles
- Storage: Refrigerate or freeze
- Why it matters: Needed to confirm exposure source. Test hay, silage, grain, minerals, water, etc.
Formalin-Fixed Tissues
- What to collect: Liver, kidney, brain, heart, lung, abomasum, rumen, muscle
- Container: 10:1 formalin to tissue ratio
- Why it matters: Some toxins cause identifiable lesions—centrilobular necrosis, renal tubular injury, myocardial necrosis.
OPTIONAL / CASE-BASED Samples
Collect when relevant to history, clinical signs, or herd investigation scope.
Heart
- Amount: Whole
- Container: Seal proof bag
- Storage: Refrigerate or freeze fresh, also fix in formalin
- Why it matters: Essential to demonstrate lesions for ionophores, selenium, some cardiotoxic plants
Urine
- Amount: Whatever you can get
- Container: Sterile container
- Storage: Refrigerate or freeze
- Why it matters: Good for water-soluble toxins and early/sublethal exposures, hypomagnesemia – need to correct for creatinine
Brain
- Amount: Whole or large portion
- Container: Bag for frozen, formalin for histo
- Storage: Freeze for chemistry, fix other half for histology
- Why it matters: Needed for sodium testing or neurotoxins, acetylcholinesterase activity, and demonstrating lesions
Fat
- Amount: Handful
- Container: Plastic bag
- Storage: Freeze
- Why it matters: Stores fat-soluble compounds, sometimes for years.
Skeletal Muscle
- Amount: 100–200 g
- Container: Plastic bag
- Storage: Formalin, need fresh for drug residues
- Why it matters: Essential for ionophores, selenium, etc.
Abomasal Contents
- Amount: 100–500 mL
- Container: Plastic container
- Storage: Refrigerate or freeze
- Why it matters: May provide more concentrated contents than the rumen, especially in calves.