Nutrition and GI: Toxicology Flashcards
(36 cards)
What is the name for a disease state that results from exposure to a poison?
Toxicosis
What samples can be used for clinical pathology of toxins?
- Urine
- Liver
- Kidney
- Blood
- Stomach contents
- Feed
- Bone/hair
What is the general treatment for toxicosis?
- Remove source
- Limit absorption/hasten elimination
- Symptomatic and supportive
What are common mineral poisoinings?
- Lead
- Copper
- Selenium
What is the role of the APHA in toxicoloty?
- Screening programmes
- Wildlife incident investigation scheme
- Emergency response- fire/flooding
- Animal disease outbreaks
What are the acute and subacute clinical signs of lead poisoning?
Acute
* young calves- typically
* found dead within 24hr
* Neurological signs- tremors, twitching, hyperthermia, salivation, rolling etes, blindness
Subacute
* Adults cattle and sheep
* Live for several days
* Neurological- dullness, anorexia, blindness, incoordination
* Staggerining, circling, muscle tremors
- When does chronic lead poisoning occur?
- How is lead poisoning diagnosed?
- Typical in lambs with high lead in soil- nephrosis is common, ill thrift, gait abnormalities, lameness
- Dx
* Clinical signs
* Heparin levels in blood
* Kidney lead levels gold standard, liver can also be used
How is lead poisoning treated and prevented?
Treatment
* Chelation therapy
* Thiamine hydrochloride
* Supportive therapy
* Rumenotomy
Prevention/Control Measures
* Remove animals from source
* Good waste managment on farm
* Check old buildings for paint, flashings etc
Following lead poisoning case what must farmers do?
- Farmers are obliged to take measures to avoid contamination of the food chain- 16 weeks
- If emergency slaughter in 16 weeks FCI saying offal discarded
- If animals close to finishing- blood lead analysis < 0.15 ok
- When does copper poisoning in cattle occur?
- What are the clinical signs?
- Access to pig feed or pasture grazed with pig manure
- Sudden onset, depressed, anaemia, jaundice and haemoglobinuria, ataxia, recumbency
What does PM or copper poisoning show?
How is it diagnosed?
PM
* Carcase- pale or jaundiced
* dehydrated
* liver pale tan or bronze
* Kidneys dark red or gun metal grey
* Urine dark red/black
* Secondary lung consolidation
Diagnosis
* History, clinical signs and PM
* Kidney copper concentrations to confirm
How is copper poisoning treated?
How is it prevented?
Tx
* Supportive therapy
* Copper antagonism
Prevention/Control
* Remember poisoning id due to efficiency or absorption and dietary availability
* Care with copper foot baths
- When does selenium posisoning occur?
- What are the clinical signs?
- Acute toxicosis occurs due to excessive supplementation
- Toxic CV, resp and urinary damage- staggering, dyspnoea, colic, diarrhoea, cyanosis, death
- What does PM show for selenium poisoning?
- How is it diagnosed?
- Sub cut haemorrhage, straw coloured fluid in pericardium, pulmonary oedema, abomastitis, intestinal and hepatic congestion, brain stem haemorrhage
- Elevated selenium in the liver, heart and kidneys
What are the clinical signs of anticoagulant rodenticides?
What is the implication for humans?
Anaemic, non-pyrexic, haemorrhages
Residues can remain in tissues for a long time, affected livestock may never enter food chain
Fertiliser
What is the aetiology of nitrate and nitrite poisoning?
Therefore what are the clinical signs?
- Excess intake
- Rumen bacteria convert to bacterial protein
- But if large quantities nitrate to nitrite which is absorbed into blood
- Converts haemoglobin to methemoglobin
Lack of O2
* Anoxia
* Cyanotic mucosae
* Tachypnoea
* Weak/rapid pulse
How is nitrate/nitrite poisoning diagnosed, treated and prevented?
Diagnosis
* Clincial signs/ history
* Blood- plasma bound nitrite
* Chocolcate brown blood
Tx
* Methylene blue IV
Prevention/Control
* Accidentally
* Can also be in docks and fat hen plants
- What can cause botulism?
- What are the clinical signs?
- How is it diagnosed?
- Use of broiler litter as fertiliser
- Often dead, if alive, recumbent with flaccid paralysis
- Clinical signs/history, PME- botulusm toxin test
No treatment
What is the aetiology of mycotoxins?
What are the financial impacts to the farm?
Aetiology
* produced by fungi
* Occur in feed routinely but usually at concentrations that do not impact health and performance
Financial impact
* Reduce crop yields
* Product rejection
* Reduced animal performance
* Increased health issues
How is mycotoxicosis controlled?
- Reduce exposure to mycotoxin
- Prevent production of mycotoxins- temp, CO2, water
- Ensure grain dried to correct moisture content
- Prevent exposure of silage to O2
- Big bale- avoid damage
- Keep straw dry
- Avoid feed, forage or bedding with visual mould
- Clen crop storage between batches
- Consider mycotoxin binder
- What causes aflatoxins?
- What are the clinical signs
- How is it treated?
- Aspergillus fungi, occur in field prior to harvest or post harvest if drying delayed/insect
- Primarily hepatic disease, decreased feed intake, decreased milk yields, recurrent infection
- None- remove source
- What causes zearalenone
- What are the clinical signs?
- Fusarium fungi- high temps, pigs more affected
- Signs of hyperoestrogenism, hyperaemia and swelling of the vulva, mammary glands, nymphomania
What mycotoxin causes facial eczema?
- Ingestion og sporidesmin, produced by the fungus
- Occurs in humid, warm wather
- Toxin concentrated in the liver causing epithelial necrosis of the bile ducts
- Ill thrify, reduced fertility
- Severly affected animals develop photosensitisation
Prevention/Control
* Oral administration of zinc salts
* Feed hay or brassica crops
* Remove stock from high risk areas
* Breed for resistance
- What causes ryegrass staggers?
- What are the clinical signs?
- Ingestion of the mycotoxin lolittrem produced by acremonium loliae found on perennial ryegrass
- Neurological signs 1-2 weeks after- fine tremors head and neck, head nodding, alteration in stance, severely affected animals
