Feeding Related Problems in Horses Exam 2 Flashcards
What two things need to be considered when selecting feeds for horses?
-nutritional value
-feed quality
How to determine nutritional value?
-nutrient requirements vary
-choose feeds that meet needs closely
-avoid deficiencies
How to determine feed quality?
choose feeds that are free from
-toxins
-microbial contaminants
-insect contaminants
-injurious materials
What can white mold cause?
respiratory inflammation
What can tall fescue become infected with?
endophytes
Where is tall fescue common?
in the Southeastern US
Endophyte
a fungus that lives inside the plant
-conveys some hardiness
What do endophytes produce?
ergot alkaloids (including ergovaline)
What affect does ergot alkaloids have on animals?
-a negative affect
-vasoconstriction (leads to more heat stress)
-hormonal disregulation
What horses are most negatively affected by endophyte infected tall fescue?
late term pregnant mares
What are the signs/problems caused by infected mares?
-delayed/absent mammary development (no milk)
-prolonged gestation
-large weak foals
-placental thickening (“red bag” at foaling)
-dystocia
What occurs during normal foaling?
the pale white/gray amnion comes out first and the chorionic surface of the placenta is still in the uterus
What occurs during red bag foaling?
the placenta has prematurely separated and the chorionic surface appears first
How to prevent endophyte infections
limit exposure of late term pregnant mares
-eliminate infected tall fescue from broodmare fields
-use tall fescue varieties without the toxic endophyte
-use other grasses in paddocks
When does ergot alkaloid production increase?
when the plant is actively growing (April, May, June)
When does ergot alkaloid production decrease?
when the plant is dormant (winter)
What time of year is there more risk to mares foaling?
late spring (rather than Jan. and Feb.)
Domperidone
a drug that will speed up foaling (won’t reverse the effects on the foal but will get the foal out asap)
EquineLeukoencephalomalacia (ELEM)
central nervous system dysfunction associated with brain damage
-“moldy corn poisoning”
Symptoms of ELEM
-ataxia
-circling/head pressing
-recumbency
-death
Treatment of ELEM
no significant treatment, but supportive therapy
What specific mold causes ELEM?
fusarium moniliforme (a type of myotoxin)
Fusarium moniliforme
-mycotoxin
-produces fumonisins
What animal is especially sensitive to fusarium moniliforme?
horses (more than cattle/swine/etc.)
What does mold usually associate with?
poor growing conditions (drought, high humidity, flooding, etc.)
Do fines or whole kernels have higher concentrations of mold and why?
fines doe because the moldy corn kernels break more easily
How can ELEM be prevented?
testing corn used in horse feeds, and contaminated corn should not be put in those horse feeds
What do blister beetles produce?
cantharidin
Symptoms of blister beetles
-contact irritant-mouth and GI (causes blisters)
-affects kidneys and heart
-cardiac irregularities
-death
What are the first signs of blister beetles?
mouth blisters and GI upset (colic/diarrhea)
How many grams of beetles are considered toxic?
4-6 grams (not a lot)
When are horses exposed to blister beetles?
-alfalfa hay
-beetles are attracted to flowers
When is contamination more likely occuring?
during flowering
When do beetles become adults?
in late spring/summer
Where are blister beetles less common?
in cooler climates
Selenium
an essential nutrient found in the soil (trace mineral)
Where in the US is selenium soil distribution low?
-north midwest
-florida
-north west coast
-canada
When may horses be deficient in selenium?
when they are fed forage only diets in selenium low parts of the country
Who is selenium deficiency most commonly identified in?
in neonates from dams in low Se areas that are not receiving fortified grain mixes
What else can be involved in Se deficiency?
vitamin E deficiency
What can Se deficiency cause?
nutritional muscular dystrophy (White muscle disease)
Symptoms of Se deficiency
-weak foals when born
-foals become weak when exercised
-skeletal and cardiac muscle affected
-white muscle disease
How to prevent Se deficiency
provide adequate Se diets
How narrow/wide is the margin between Se deficiency and Se excess?
very narrow (most narrow margin nutrient)
Symptoms of chronic toxicity of Se
loss of hair and hooves
Toxicity of Se affects what?
the bonding in certain sulfur containing amino acids
When does chronic Se excess/toxicity exposure occur?
-consumption of Se accumulator plants in high Se areas
-over supplementation
When is Se toxicity relatively uncommon (unless oversupplmented)
KY
Symptoms of acute Se toxicity
-muscle dysfunction
-cardiac dysregulation
-death
When does acute Se toxicity exposure occur?
injectable Se overdose
What are some other feed related problems in horses?
-feed contamination by antibiotics/growth promoting compounds used in other species
-feed mixing errors that add too much of a nutrient
-feed contamination by rodents/wildlife
