Forage Toxicity Flashcards
Grass tetany other names
pasture poisoning
grass staggers
hypomagnesemia
factors that limit Mg availability
-low Ca and Mg levels in forages
-grazing fall and winter cereal grains pastures
symptoms of grass tetany
-twitching and falling down
-loss of muscle control
-convulsions
-nervousness/excitement
-how quickly can cows die from grass tetany
within hours of symptoms starting
treatment for grass tetany
IV magnesium
cattle at higher risk for grass tetany
pregnant or lactating
older cattle
T/F horses are less likely to suffer from grass tetany then ruminant animals
TRUE
prevention of grass tetany
-apply limestone to acid/sandy soils
-graze dry/stocker cows in pastures that could cause it
-supplement Mg
Mg supplementation, and their drawbacks
-Mg oxide: not very palatable, expensive
-Mg in liquid feed: difficult to get 2 oz/hd/day
-Mg source in range cubes
Acute Bovine Pulmonary Emphysema other names
fog lung
lungers
causes of ABPE
-switch from low quality forage to very high quality forage
-tryptophan is converted to 3-methylindoe
what is the end toxic species that causes ABPE
3-methylindole
what grass is most commonly associated with ABPE
Bermuda grass
clinical signs of ABPE
-labored breathing
-respiratory distress
-grunting
-extension of tongue/drooling
animals at higher risk of ABPE
-cattle
-mature animals
T/F nursing calves are highly susceptible to ABPE
FALSE. they rarely get it since they dont graze as much
which cattle breed is less susceptible to ABPE
Brahman(bos indicus)
treatment of ABPE
-no treatment to reverse damage
-slowly remove cattle from offending pasture to prevent continued damage
prevention of ABPE
-gradually introduce to lush pastures
-feed hay before introducing to a lush pasture
-supplement rumensin
causes of dallisgrass poisoning
seedheads of mature dallisgrass become infected with fungus that produces ergot toxin
where does ergot infection most commonly occur
eastern regions of Texas
clinical signs of dallisgrass poisoning
-hyperexcitement
-stumbling
-muscle trembles
-incorordination
T/F animals do not typically die from dallisgrass poisoning
TRUE
T/F horses are not affected by dallisgrass poisoning
FALSE. if they eat hay containing infected seeds they will get sick, eating the seed is less common bc they are not grazers
treatment of dallisgrass poisoning
-slowly remove cattle from pasture
-provide supportive care
prevention of dallisgrass poisoning
shred mature dallisgrass to height of 8 in(dont let seed heads form)
nitrate toxicity
nitrate is converted to nitrite in the rumen which oxidizes hemoglobin to methemoglobin which can not hold O2
factors that cause nitrate concentrations to increase
drought
frost damage
extensive shade
herbicide treatment
high soil nitrate
what grass often leads to nitrate poisoning
johnsongrass
what is nitrate typically converted to, what stops this cause nitrate poisoning
Ammonia. rate of NH3 usage decreases nitrate will build up and be converted to nitrite
clinical signs of nitrate poisoning
colic pain
diarrhea
dyspnea
staggering
abortion
what toxicity causes “chocolate blood”
nitrate poisoning
how fast can nitrate poisoning symptoms occur
.5-1 hour post ingestion
animals most susceptible to nitrate poisoning
ruminants
treatment of nitrate toxicity
methylene blue intravenously
(6 month withdrawal time)
prevention of nitrate toxicity
-have nitrate levels analyzed
-dont feed forages with greater than 1.5% nitrate on a DM basis
-feed grains in tandem with higher nitrate forages
what is the rule of thumb regarding nitrate levels
feed 1 lb of corn per day for each 0.1% nitrate in excess of 1%
cause of prussic acid poisoning
-plants high in prussic acid/HCN
-Microbes convert HCN into cyanide
-cyanide prevents cells from absorbing O2
factors that cause elevated prussic acid concentrations
drought’
frost damage
rain following drought
herbicide trearment
forages commonly associated with prussic acid poisoning
sorghum
johnsongrass
Tifton 85
what feature will grass high in prussic acid have
ribbon-like waves on leaf
clinical signs of prussic acid poisoning
-excitement
-dyspnea
-hyperpnea
-cyanosis
-tachycardia
-unconsciousness
-cherry red venous blood
how quickly can prussic acid poisoning kill
within minutes of exposure
animals most susceptible to prussic acid poisoning
ruminants, microbes have enzymes that release prussic acid
treatment for prussic acid poisoning
-administer sodium nitrate followed by sodium thiosulfate intravenously
prevention of prussic acid poisoning
do not graze new-growth sorghum plants or graze them with full rumens
kleingrass poisoning
saponins in kleingrass can not be detoxified by liver and cause liver damage, leading to no chlorophyll breakdown
clinical signs of kleingrass toxicity
photosensitivity
discharge from eyes and nose
why does kleingrass poisoning cause photosensitivity
extra chlorophyll in skin
what toxicity causes “big head syndrome”
kleingrass poisoning
what animals are at highest risk of kleingrass poisoning
sheep, goats, and horses
prevention of kleingrass toxicity
-remove animals from pasture and into the shade
cause of fescue grass toxicity
alkaloids produced by a fungus found in the forage
clinical signs of fescue toxicity
-reduced feed intake
-reduced milk production
-lower conception rates
-abortion
-rough hair coat
reduced blood flow to extremities(fescue foot)
what does fescue grass produce that is toxic
endophyte
T/F maintaining endophyte-free fescue grass is a easy way to prevent fescue toxicity
FALSE. while it works for a time, fescue grass containing endophyte will eventually come back
animals most susceptible to fescue toxicity
cattle
horses
treatment of fescue grass toxicity
supportive therepy
prevention of fescue toxicity
-observe animals
-graze fescue pastures intermittently
-mixed species pastures
genetic prevention of fescue toxicity
T-snip genetic markers
0-1=susceptible
4-5=tolerant