Johne's and Toxicology Flashcards
What are 2 clinical signs of John’s?
What are 3 signalments?
- Weight loss
- Profuse diarrhoea
- Animal over 3 years old
- Bright and eating
- After calving (stress)
What is the most common transmission route for John’s disease?
New born calf
SiM and pooled colostrum
In Johne’s disease, how does a calf go from being infected to infectious?
Cell-mediated immunity is initially protective against disease progression
If disease progresses, antibody response suppresses CMI
Animal starts shedding
What is a “super-shedder” of Johne’s disease?
> 1 million cfu/g faeces
How do you test for Johne’s infection in the HERD?
Target sampling (30 cow screen) Select 30 cows most likely to be positive, test milk/blood antibody
What is the relationship between MAP and M. bovis (TB)
Cross-reaction
False negatives in Avian TB test
False positives in Mammalian TB test
False positive in MAP test if TB test < 3 months prior
What are 4 ways to prevent John’s?
- Snatch calving at birth
- Keep youngstock and adults separate
- NO feeding of pooled colostrum or waste milk
- Purchase animals from low risk herds
What is the purpose of “Gudair” (MAP vaccine)
What is the main problem with it?
Reduces incidence of clinical disease
Does NOT prevent infection
Interferes with MAP and TB tests
When is Johne’s applicable in a Beef Suckler herd?
What is the main option prevention?
If rearing replacements
Outdoor calving
What clinical signs does lead poisoning cause?
Neurological: blindness, circling, tremors
What are 3 treatments for lead poisoning?
- Chelation (EDTA)
- Thiamine hydrochloride
- Rumenotomy
What is the voluntary withdrawal period for lead poisoning?
For normal slaughter and enter into the food chain, what should the concentration of blood: lead be?
What needs to occur if blood lead: lead concentration is above 0.48umol/l?
16 weeks
< 0.15umol/l
Testing of carcass
What breed of sheep is susceptible to copper toxicity?
Texel
What is a common cause of copper toxicity in cattle?
Name 3 clinical signs
Pig feed or manure
- Sudden death
- Anaemia, haemoglobinuria
- Jaundice
What is the treatment for copper toxicitiy?
Copper anatagonists: Molybdenum or sulphur
What is Ryegrass Staggers caused by?
What type of clinical signs does it cause and what is the timeframe?
Mycotoxin produced by Acremonium loliae
Neurological, 1-2 weeks after exposure:
Jerky movements, fine tremors, head nodding, tetanic spasms
What type of toxin causes Deoxynivalenol?
What fungus produces it?
What type of feed is it related to?
Vomitoxin produced by Fusarium fungi (mycotoxin)
Cereals: wheat, barley, oats
Which fungi produces Alfatoxins?
What type of feed is the most high risk?
Aspergillus fungi
Corn
What do Alfatoxins cause? (2 things)
Carcinogenic
Hepatic disease
What species does Zearalenone toxicity affect?
Name 3 clinical signs it causes
Pigs
- Hyperoestrogenism
- Decreased fertility in boars
- Rectal/vaginal prolapse
What is Claviceps purpurea?
What disease does it cause and how?
Parasitic fungus of rye
Ergotism
Ingestion of ergot alkaloids
What are 4 clinical signs of Ergotism?
- Gangrenous lesions
- Painful/cold/numb extremities
- Abdominal pain
- Vomiting
Which disease is caused by a mycotoxin, resulting in photosensitisation?
In sub-clinical cases, how is it diagnosed?
What does it cause in the liver?
Facial eczema (fungi: Pithomyces chartarum)
GGT concentration
Hepatic disease and necrosis of bile ducts
What is a common cause of botulism?
What are 3 presentations of botulism?
Can affected animals enter the food chain?
Broiler litter used as fertiliser 1. Found dead 2. Recumbency with flaccid paralysis 3. Ataxic Not for human consumption if affected. If recovered, withdrawal period of 18 days
What is the pathogenesis of Nitrate poisoning?
Accumulation of NITRITE, converts haemoglobin into methaemoglobin (which can’t transport O2)
What are 3 clinical signs of Nitrate poisoning?
What is the treatment?
- Tachypnoea
- Cyanotic MM
- Weak and rapid pulse
IV Methylene Blue
What does thiamine deficiency cause in:
- Pigs?
- Sheep?
- Cattle?
- All species?
- Cardiac enlargement
- Bright blindness (retinal degeneration)
- Enzootic haematuria
- Pancytopenia and tumors of bladder wall
What plant causes thiamine deficiency and how?
Bracken
Thiaminases
What plant causes goitres and frothy bloat?
Clover
What plant causes Pyrrolizidine Alkaloid toxicity?
What does it cause?
Ragwort
Hepatoxic
What toxicity causes black tarry faeces and haematuria?
What plant contains these toxins?
Phenols and tannins
Acorns (oak)
In which plant toxicity is vomiting the pathognomic sign?
Name 3 other clinical signs
Rhododendron poisoning (Polycyclic diterpenes)1. Staggers
- Recumbency
- Tremors and paddling
Name two causes of Nitrate poisoning
BrassicasFertiliser (e.g. run-off into cattle housing)
What plants cause Nitrate poisoning, SMCO and are goitrogens?
Brassicas (rape and kale)
On what parts of the skin does photo sensitisation occur?
What 2 plants cause photosensitisation?
Non-pigmented or hairless areas of the skin
St John’s Wort
Ragwort
What plant causes sudden death?
Yew (taxine poisoning)
What is the MAIN sign of anthrax upon finding a dead animal in a field?
How do you take a blood sample if anthrax is suspected?
How do you diagnose on cytology?
What should you do if anthrax is suspected?
NO RIGOR MORTIS (and black tarry blood from nose/rectum)
DON’T use vacutainers (clostridia will stain like anthrax)
Use surgical spirit to burn cut skin
Stain methylene blue, anthrax stains PINK
Inform APHA and DON’T MOVE ANIMAL
