Farm animal Toxicology Flashcards
What samples can be taken to check for toxicology?
- Urine
- Liver
- Kidney
- Blood
- Stomach contents
- Feed
- Bone / hair
How would you treat a toxic case?
- Remove source
- Limit absorption / hasten elimination
- Symptomatic + supportive Tx
What are common mineral poisonings?
- Lead
- Copper
- Selenium
What are clinical signs of lead poisoning?
- Acute poisoning = young calves - neuro signs, muscle tremors + twitching, hyperthermia, salivation, rolling eyes, bellowing, blindness, stiff gait, convulsions w opisthotonos + pupillary dilation
- Sub-acute = adult cattle + sheep - neuro signs = dullness, anorexia, salivation, blindness, incoordination, staggering, circling, muscle tremors, colic, ruminal atony, recumbency
- Chronic = lambs w access to soils in high lead = nephrosis, ill-thrift + gait abnormalities, osteoporosis, abortion + infertility
- Subclinical = chronic exposure at low levels = no clinical signs
How is lead poisoning diagnosed?
- CS
- Heparin - >0.48umol/litre
- Kidneys lead levels = gold standard
What is Tx of lead poisoning?
- Chelation therapy
- Thiamine hydrochloride
- Supportive therapy
- Rumenotomy
How is lead poisoning prevented / controlled?
- Remove animals from source
- Good waste management on farm
- Check old buildings for paint, flashing etc
- More difficult if soil contamination
When do cows tend to get copper poisoning?
- If access to pig feed or grazer pasture fertilised with pig manure
What are clinical signs of copper poisoning in cattle/sheep?
- Sudden onset
- Depressed
- Anaemia
- Jaundice + haemoglobinuria
- Ataxia
- Recumbency + death
What’s seen on PME of copper poisoning?
- Pale / jaundice carcase
- Dehydrated
- Liver = pale tan
- Kidneys = dark red / gun metal grey
- Urine dark red / black, secondary lung consolidation
How is copper poisoning diagnosed?
- Hx, CS + PME
- Kidney copper conc used to confirm Dx
What is Tx of copper poisoning?
- Supportive tx
- Copper antagonists = molybdenum / sulphur
What are clinical signs of selenium poisoning?
- Toxic damage to CV, Resp + urinary systems + Damage secondary lymphoid tissue
- None specific = staggering gait, dyspnoea, tympany, colic, diarrhoea, recumbency, cyanosis, death
What is seen on PME of selenium poisoning?
- Sub-cut haemorrhages
- Straw coloured fluid in pericardium
- Severe pulmonary oedema
- Abomastitis
- Intestinal + hepatic congestion
- Brainstem haemorrhages
- Destruction of renal cortices
How is selenium poisoning Dx?
- Elevated selenium in liver, heart + kidneys
- What is Tx + Px of selenium poisoning?
- Tx = NO TREATMENT
- Px = ensure correct doses when giving supplements + proper mixing
What are clinical signs of anticoagulant rodenticide poisoning?
- Anaemic
- non-pyrexic
- weak
- haemorrhages
What is aetiology of nitrate / nitrite poisoning?
- Excessive intake of nitrate
- Rumen bugs = nitrate => nitrite => Ammonia => Bacterial protein
- If lots of nitrate consumed = accumulation of nitrite which is absorbed into bloodstream + converts haemoglobin into methemoglobin which cannot transport oxygen
What are CS of nitrate + nitrite poisoning?
- Due to lack of oxygen
- Anoxia, cyanotic mucosae tachypnoea, weak + rapid pulse
- Sub acute + chronic forms more vague in signs
How is nitrate / nitrite poisoning diagnosed?
- CS / Hx
- Blood - plasma protein bound nitrite
- Chocolate-brown discoloration of blood
What is Tx of nitrate/nitrite poisoning?
- Methylene Blue IV
What is aetiology of botulism?
- Often associated with the use of broiler litter as fertiliser (ingestion of pre formed toxin - rotten carcass’s types C and D, rotten plant material type B)