Final Exam Flashcards
(103 cards)
What factors in plants increases risk of mycotoxin production?
Stress due to drought, flooding, poor soil fertility
How are mycotoxins distributed in feed?
Unevenly, in pockets. Toxins can persist after fungi are gone.
What animals are most susceptible to mycotoxins?
Monogastrics are at highest risk (poultry, swine), Horses are monogastrics, but at less risk, ruminants least susceptible, but pre-ruminants are fully susceptible
What is the potential role of mycotoxin contamination in causing animal health problems?
If animals eat contaminated feed can cause drop in production directly or due to secondary infection.
What are the risk factors associated with the formation of mycotoxins in feed ingredients? Does mold mean that there is mycotoxin present?
Stress to plants, less likely in surface “spoilage” organisms, more likely to produce mycotoxins if infecting living tissues, highly dependent on environmental factors and mold ≠ mycotoxins.
What are some feeding situations that could be associated with ingestion of mycotoxins?
Monogastric animals eating corn or cereal grains. Whole oil seeds. Cattle eating mycotoxin-positive feed in large amounts.
What are some clinical signs that could be associated with ingestion of mycotoxins? What other diseases are rule outs?
Key sign of mycotoxicosis is feed refusal. Also ill-thrift, weight loss, usually all animals in group. Can be immune suppressive, leading to secondary infections. Rule outs are subclinical metabolic, nutritional, or infectious diseases.
How would you test for mycotoxins?
Start by testing whole diet, then feed ingredients. Black light for Aspergillus, on site qualitative tests, full wet chemistry testing
How would you treat and prevent mycotoxin contamination?
Once mycotoxin concentrations known, remove or dilute feed and wait >1 week to observe for improvement. Could try binders. Best approach is to prevent fungal growth in the first place. Prevent storage contamination- harvest, store, silage properly. Use preservatives. Delay grinding, avoid screenings.
Name some common mycotoxins and where they are found/sources.
Aflatoxin (warm climates, high humidity) corn, potatoes, wheat, soy, peanuts, distilled products
Fumonisins (corn especially broken/screenings)
Zearalenone (corn, other grains) ‘pink ear rot’ ‘scab’
Trichothecens (corn)
Ergot (Ryegrass)
Slaframine (clover, clover hay) ‘slobbering factor’
Tremorgens (Grasses, spoiled foods/garbage)
What are the primary effects of aflatoxin? Most susceptible species?
Hepatotoxocitiy, carcinogenesis. Swine most sus. Regulated in milk bc carcinogenic in humans. Young animals more sensitive. Stunted growth. Acute- hemorrhage, bloody diarrhea death. Chronic- icterus, fatty liver, anemia, ascites.
What are the primary effects of fumonisins? Most susceptible species?
Leukoencephalomalacia in horses most sensitive (CNS, death), also swine (porcine pulmonary edema due to heart failure in pigs)
What are the primary effects of Zearalenone? Most susceptible species?
Weak Estrogen. Swine most affected. Vulvar issues, infertility, prolapse.
What are the primary effects of Trichothecens? Most susceptible species?
T2 toxin- immunosuppression in pigs. DON/Vomitoxin! Swine most sus, also small ruminants (vomiting! Rare)
What are the primary effects of Ergot? Most susceptible species?
Extreme vasoconstriction, gangrene/sloughing of extremities. Cattle.
What are the primary effects of Slaframine? Most susceptible species?
Horses ‘slobbering factor’, excessive salivation key sign
What are the primary effects of Tremorgens? Most susceptible species?
CNS overstimulation and tremors. Grazing animals
What type of compound is Monensin? What is it used for?
Polyether Acid Ionophore Antibiotics. Not useful for pathogens, alters rumen biota favorably.
What is the method of action for Monensin?
Alters ion channels in cell walls, heart and skeletal muscle most affected.
What species is monensin approved for use in? Is it always safe in these species?
monensin is approved for cattle, goats, chickens, turkeys, and quail. Still toxic if overdosed.
What species are most susceptible to Monensin toxicity? Clinical signs?
Sensitivity varies with ability to oxidize monensin. Horses very sensitive, cows much less sensitive. Neuro signs, cardiac muscle in horses, skeletal muscle cattle. CHF key sign in horses.
How can you prevent monensin toxicity?
Feed mills cleaning equipment to avoid cross-contamination, avoid totally in small mixed species operations to prevent cross-contamination.
Would you feed cotton products to monogastrics? Why?
No. Gossypol. unbound toxic. Ruminants bind 8x more than monogastrics.
What is gossypol? Who is it toxic to?
Yellow pigment found in cotton plant at highly variable concentrations. Free Gossypol is toxic to all animals- less so to cattle bc bound in rumen. Cotton seed is main concern.