Exam 2: Lecture 14 - Equine nutrition 2 Flashcards
what are the problems with bermuda grass even though it is excellent pasture
- can rapidly become fibrous and cause impaction colic when it is tall and mature
- coastal bermuda can cause ileal impactions in horses
what is the problem with endophyte fungus present in endophyte-infected fescue
- poor growth
- prolonged gestation, thickened placenta, agalactia (cant produce enough milk) in mares
- increased foal mortality
what are the problems with alsike clover
- linked to liver disease in horses
- neurological signs (hepatic encephalopathy)
- wasting
- photosensitization
what is the problem with red clover
occasionally contaminated with fungus called rhizoctonia leguminicola
what does the fungus, rhizoctonia leguminicola, cause in horses
produces slaframine which is a toxin slowly degraded during storage of hay, also a source of phytoestrogens
what is a large contributor of laminitis
high concentrate diet/grain overload
how do high concentrate diet/grain overload cause laminitis
- delivery of too much starch to large intestine
- high starch fermentation can lead to diarrhea, colic, or laminitis
how do we prevent laminitis and high concentrate diets
- limit concentrate feed to a max of 0.5% of body weight
- always feed at least 50% of hay
T/F: digestibility of starch in small intestine very high for some grains
true!
how do large amounts of starch reaching large intestine change the local environment
- high amounts of grain/fermentable carbs lower intestinal pH
- lower pH = more gram-negative bacterial die (means there are more gram positive and produce lactic acid)
what is the result of too much grain/fermentable carbs reaching large intestine
- changes in bacterial populations can result in endotoxin release
- endotoxins
- diarrhea, colic
- laminitis
T/F: high levels of non-structural carbs (NSC, soluble carbs) in forages can cause laminitis
true!!
T/F: ideally fructans, sugars, and starch would all be digested in SI but 30-50% reaches LI where they are rapidily fermented
true
what are the problems caused from excessive NSC in LI
- overgrowth of bacteria that ferment starch and fructans
- destruction and inflammation of gut wall
- damage allows absorption of toxins
- causes laminitis
Should WSC, ESC, and ESC + starch be low or high for laminitic horses
ESC should be low
WSC should be low
ESC + starch should be low (<10%)
when do fructans accumlate
when rate of photosynthesis exceeds use of energy for growth in plants
(cool weather, after a frost, drought, later in the day)
T/F: there are the highest levels of fructans in fall glasses
false! highest levels are in late spring
why are fructans dangerous
- not digested by mammalian enzymes
- escape SI, rapidly fermented in LI
- more dangerous than starch
what is laminitis
inflammation of laminae of hoof wall that causes pain, separation, rotation/sinking of pedal bone
experimentally, how has laminitis been induced
starch 18 g/kg DM
fructans 10g/kg DM aka 5kg per 500kg horse
T/F: pasture grasses can accumulate >400g fructans/kg DM
true!!!
how can we avoid pasture-associated laminitis
- restrict grazing, especially in spring
- supplement with hay made from mature grasses or legume containing hay
- NSC content of hay can be reduced by about 30% by soaking in water for 30-60 mins
- analyze grasses and hay for NSC
- avoid obesity
- horses with previous laminitis episodes especially at risk
T/F: NSC less than 12% may contribute to issues in problem horses
false!! NSC ABOVE 12%
what contributes to almost half of the cases of laminitis
grazed lush pastures!! (45.6%)
what are the problems with caring for laminitic horses
- clients have only one big pasture
- no stalls available
- short supply of hay
- lack of owner compliance
- cost involved in providing ideal care
what are the costs involved in providing ideal care of horses with laminitis
- make a dry lot
- buy quality hay and have a nutrient analysis performed
- pay for regular farrier care
- pay for meds and follow up on case
which forage is associated with ileal impactions in horses?
A. Tall fescue
B. Alsike clover
C. Bermuda grass
D. Red clover
C. Bermuda grass
what are the predisposing factors of cribbing
- stall weaning vs pasture weaning
- stall housing following weaning
- feeding concentrates
- lack of time at pasture
- lack of straw bedding in stall
what are the problems with cribbing and what are the treatments
problems: causes wear and tear on teeth
treatment: increase dietary fiber, remove ledges, electric fence, creosote, dog collar, cribbing collar, sx
T/F: Gastric ulcers are most common in performance horses and foals
true!
where do gastric ulcers more frequently occur in horses
non-glandular stratified squamous mucosa
what are the risk factors of gastric ulcers
- intense exercise
- increased stall time
- meal feeding
- not having hay available ad libitum
T/F: feeding alfalfa and aloe vera juice can be protective for gastric ulcers
true!!
what are the ways prevention of gastric ulcers
- diet
- management
- treatment
how do we prevent gastric ulcers with diet
- feed alfalfa or pasture (alfalfa buffers acid)
- roughage continuously available stimulates saliva which is rich in bicarb
- avoid large grain meals
how do we use management for prevention of gastric ulcers
reduce stress and increase turnout time
what can we use for treatment of gastric ulcers
gastrogurd (omeprazole) and ulcergard
which type of carb in grass can contribute to excessive LI fermentation and may result in laminitis?
A. starch
B. fructans
C. cellulose
D. glucose
B. fructans
what is heaves in horses
allergic respiratory disease of horses characterized by chronic cough, nasal discharge, and respiratory difficulty
what are other names for heaves
recurrent airway obstruction/COPD/broken wind/emphysema
how can we help feed horses with heaves
- avoid dusty, mold hay
- feed cubes
- soak hay
- avoid hay storage above horses in barn
- pasture the horse
- hay gain system (steam sterilizes hay)
how long do we need to soak hay for horses with heaves
60 mins in cold water, 30 mins in warm water
what is the problem with soaking hay
it will leach out other nutrients!!!
about 30% reduction in sugar content and >50% reduction in potassium
what is vitamin E deficiency in horses caused by
an issue with poor quality hay and grain
what can vitamin E deficiency cause in horses
- equine degenerative myeloencephalopathy
- equine lower motor neuron disease
what do we see in horses with equine degenerative myeloencephalopathy
- possible hereditary component or vit E deficiency
- intracellular damage via oxidation
- ataxia, proprioceptive deficits, weakness and spasticity of all four limbs with the hind limbs often being the most affected
what do we see in horses with equine lower motor neuron disease
- older horses deficient in vit E for 18 months or longer
- neurodegenerative disorder of the horse characterized by progressive weakness, fasciculations, muscle wasting, and weight loss
why does food get stuck in the esophagus in horses
esophagus passes thru the thoracic inlet and behind the base of the heart
when is choke/obstruction common in horses
- if horse bolts food with chewing properly
- more common with pelleted feedstuffs, cubes, beet pulp
what does choke look like in horses
horse extends head and neck and may have nasal discharge
how can we prevent choke in horses
wet to prevent - feed gruel or mash
what is leukoencephalomalacia in horses
fumonisin toxicity that causes neurological signs
why do we see neurological signs with leukoencephalomalacia
because there is liquefactive necrosis of the cerebral white matter
what are the clinical signs we see with leukoencephalomalacia
progressive ataxia, depression, anorexia, delirium, aimless wandering, recumbency, coma and death can occur 12 hrs to 1 weeks after onset of signs
