5a. Feeding Horses Flashcards
What are unique facts about equine digestion?
hind gut fermentors
Selective grazers - prehensile, sensitive lips
grind food w/ molars - grow continuously
eat thruout day - sm stomach, no gall bladder
monogastric - mammalian digestion in sm intestine, fermentation in cecum and large intestine
What is the optimal characteristics of giving water to horses?
must have access to fresh, clean water
storage tanks, troughs or pails
water lvls kept high enough - reluctant to place head in a trough or pail below eye lvl
Optimal temp 20-26C
average minimal water intake is 5L/100kg BW/day - inc w/ work req and diet, if fed only dry hay, req double, lactation or sweat losses inc needs by 50-200%
What is maximum dry matter intake?
the most food a horse can consume in a day
it increases with need and the digestibility of the feed
1.5-2% of BW, maintenance - 1000lb horse = 20%
3% of BW, peak lactation
growth 3.5% (nursing/weaning) to 2%
What is the difference in energy needs of easy keepers vx hard keepers
nonworking in good BCS easy keeper: 30kcal(0.03 Mcal)/kg BW
Hard keeper
40kcal (0.04 Mcal)/kg BW
How might cold weather, growth, preg/lactation and work affect energy needs?
COLD: lack adequate shelter otside
GROWTH: rapid and slow growth periods
PEG/LACT: maintenance until last 90d of gestation, inc in energy needs by 10-20%, lact may req 2-3x maintenance
WORK: type of work, condition and training of horse, enviro, skill of driver or rider
What are protein requirements?
some microbia synthesis and absorption of AA occurs in cecum and lg intestine
not sufficient to meet the amino acid needs
What might affect the protein requirements?
growth(14-16%total ration), mature horses(8-10), aged (>20yrs)(14-16), pregnancy(10-11%), lactation(12-14)
What are some mineral requirements for horses?
calcium and phosphorus - greater needs during growth, last third of preg, lactation
phosphorus needs of older horses may be higher
maintain ratio >1:1
What are some nutritional problems at growth that could occur?
developmental orthopedic dz
Flexural demformity
What is developmental orthopedic dz?
include deformed limbs (angular limb deformities) and bone malformations that cause problems later in life
Too much grain (energy)
improper amount of minerals like Ca, P, Cu and Zn
Exercise strengthens bone
Inheritance also most likely cause
What is a flexural deformity?
inflam of growth plates (physitis)
2nd to insulin dysregulation from rapid digestion of easily available carbs
Physitis results in pain and lack of weight bearing - unstretched tendors cause flexural deformities
Tx/prevention - restrict energy-heavy feed, no alfalfa, timothy (low energy hay)
What are some qualities of feeding at pasture/
pasture should be permanant, mixture of grasses and legumes (boost protein and energy content)
over mature pasture (stems and flowers) is poor quality grazing for horses
What does it mean that horses are selective grazing
graze the palatable areas to the ground, leave the stemmy areas to overgrown, will not graze ner fecal pats
Why is pasture rotation important?
parasite control (no/few eggs survive prairie winters), diff types for diff seasons
Grass for spring, alfalfa for summer
How should pastures be utilized?
prevention of over or undergrazing
if they’re grazing the pasture close to the ground -move to prevent damage to plants
If overgrazing - mow for hay
overgrazed pastures contribute to inc parasite burdens and favor overgrowth of weeds
Avoid lg pastures to ensure appropriate size and access - 1 acre per horse
Horses avoid feces (latrines)
avoid forages w/ a lot of stem
results in roughs and lawns (good areas)
Cows will eat the rougha nd graze near feces
How could we manage a pasture?
chain harrow to spread manure - hot dry periods, no horses
Clip or mow or spo 2, 4-D (selective weed killer) application to remove unpalatable weeds - once a year
How can you tell if a pasture is adequate?
condition of horses/pasture, analysis of plants
most horses can maintain a BW when fed good-quality forage, water and a mineral block
What is pasture-associated laminitis causing NSC
non-structural carbs (NSC)
sugars, fructans and starch
rapid growth pastures (spring, summer, fall after heavy rain) favor accumulation - ideally digested in sm int, up to half the starch and all the fructans can reach lg intestine where it is rapidly fermented
What happens with excessive NSC in the lg intestine?
overgrowth of bact that can digest starch and fructans
prod lactic acids, lower pH
destruction and inflam of gut wall, absorb of toxins - colic, diarrhea, laminitis -systemic inflam response that contributes to destruction of lamellar epithelium and matrix
What are the risk factors of NCS
genetic predispositions, equine metabolic syndrome (obesity, insulin-resistance, hyperinsulinemia)
How can we reduce the occurance of NCS?
RESTRICT GRAZING - especially spring early summer - rapid growth
Pasture overnight/early morning - fructans inc thruout morning and reach max values in afternoon
Grazing muzzles, hay steamers
Avoid stemmy, mature pastures - contain more fructans
Avoid grazing in low temps - dec grass growth and inc fructans
Supplement w/ hay - mature grasses or legume containing hay
Soak hay - 30-60m
analyze grasses and hay for NSC and feed low NSC hay <10%
avoid obesity
equids w/ prev laminitis episode especially @ risk
What is tall fescue?
Endophytic fungus
poor growth, prolonged gestation and agalactia in mares, inc foal mortality
Why might we feed preserved roughage?
fed to satisfy maintenance requirements
at least 50% of diet - higher conc inc risk of laminitis and obesity, except intense exercise, feed smler, frequent feedings of concentrates, no more than 0.5% BW per feeding
Good quality hay fed at 1.5% BW
Poor quality hay is about 2/3 the energy content - adjust feeding amounts
Always allow up to 30% extra for waste
What are grass hays and its characteristics, what is it best for?
Timothy, brome
lower in cals and protein
Higher in fibre- support hindgut fermentation
best for: easy keepers, stalled horses, to support GI health
What are legume hays, in what types of horses can we replace 10-20% of grass
alfalfa, clover
higher in energy, protein and calcium
lower in fibre - not advised as sole diet
Can replace 10-20% of grass hay -> heavy work or training, lactating mares, growing horses, to improve palatability
What are the different methods of feeding hay?
continuous acess
round bale feeder
some put out mixture of good hay and straw bale to prevent obesity
hay rack
hay net
if group feeding there must be adequate space so that all horses can eat
What are some problems of feeding with hay
dust - equine asthma syndrome, heaves, recurrent airway obstruction, chronic obstructive pulmonary disease, speak hay and feed close to ground, pelleted hay alternatives
Mold
Choke - hay cubes, soak cubes
What do we need to keep in mind when feeding straw
unintentional - eat bedding
Intentional - part of diet, fat horses, low K diets, oat straw vs wheat straw
problems - impactions
Why might we feed concentrates?
some horses req concentrate supplement bc their lactating mares, weanlings, yearlings, working horses
Fed ad lib or limit fed (better)
If limit fed - have N+1 bowls, feed 2-3xd, inc portion of concentrate - when grass is mature (flowering or flowered) when grass is not growing
In horses, what BCS do we want them at. What about max concentrate portion?
max conc portion of diet 50% (weanlings)
Maintain weanlings in lean to mod BCS 4
ribs barely visible, cannot see bony structures of hips or lumbar vertebrae, dec risk of DOD/OCD
How might we want to feed working horses?
free choice good quality hay can support moderate work
Must feed concentrate (grain) to heavily exercising horses as cannot eat enough hay to meet needs
often advantageous to feed all exercising horses some grain - at least half the diet should be roughage to stop GI problems,
reduces hay belly - extra weight the horse does not need to lug around while trying to work
What is the type of concentrate: oats
most traditional
processing improves digestibility
hulled oats more energy dense
What is the type of concentrate: barley
higher in energy than oats
causes lower glycemia response
good choice for insulin-resistant horses
What is the type of concentrate: corn
high-energy feed
hard working horses, horses in need of weight-gain
inc risk of laminitis or colic
How might we feed fat and performance horses?
endurance horses burn fat - endurance rides, 25-100kn over 1-2d
Beneficial to acclimate to fat utilization by feeding fat
feeding trials show benefits of adding fat to diet of endurance horses
reduces risk of grain overload type problems as replaces some of the grain
What is supplemental fat?
typical diets are about 2.5-3% fat
Can add fat up to 10% of diet
Must acclimate horses to higher levels of fat
High levels of fat will require careful balancing of protein and minerals in diet
may improve coat sheen
Reduces gastric acid secretion (Helps prevent ulcers)
Sources - corn oil, rice bran, canola oil
Why might pelleting and pellet feeds be useful?
done by grinding ingredients >mixing and compacting particles > steam heating at high temps > pushed thru pellet die
Grinding increases feeds overall digestibility
Low dust (good for resp patients)
low moisture lvl (resistant to mold and freezing
Why might extrusion and extruded feeds be useful?
grinding and mixxing ingredients > steam heat, pressure and extremely high temperatures > mash sent thru extruder > die used to give shape
Good for pre-cecal digestibility of starches
Slow feed intake
Why might textured feeds be useful?
aka sweet feeds
Historically, a mixture of oats, corn and molasses - nutritionally incomplete
Now see addition of pellets - contains minerals and vitamins
molasses increases palatability
moisture content increases risk of mold/freeze
What is starch in the equine diet?
too much delivery of starch to lg intestine
fermented can cause diarrhea, colic and laminitis as for fructans
Prevent by limiting a concentrate feeding to a maximum of 0.5% of BW, feeding at least 50% hay
What is cribbing?
wind sucking, aerophagia, stable vice/oral stereotypy
Predisposing factors - weaned in a stall rather than a pasture, kept in a stall following weaning, being fed concentrates, lack of time at pasture, lack of straw bedding in stall
more susceptible to colic
What are gastric ulcers?
most common in performance horses - 60-80% of racehorses in training
risk factors: exercise, inc time in a stall, feeding in meals, not having hay available ad lib
feeding alfalfa is protective - calcium buggers gastric pH
Signs: colic, poor performance
treat with antacids, H2 blocker (gastrogard
Prevent - diet, feed alfalfa or pasture (alfalfa buffers acid), roughage continuously available, avoid lg grain meals, add oil (450ml) to diet
What are other feeding supplements?
brans,pulps, fats and oils, molasses
What is brans?
wheat bran and rice bran are brain by-products
water, palatant, fat (calories)
high phosphorus content, limited feeding
What is pulps?
beet pulp by-product of sugar beet industry
source of calories and fibre, must be soaked
Why might fats and oils be used?
increase energy density - corn, soy and other vegetable oils
Why might molasses be used?
palatable
reduces dusts of concentrate mixtures
Why might dentition matter in geriatric horses?
60% of horses >20yrs
expired teeth (cupping out) - continuously growing teeth, but reserve crown is finite, enamel wears away, dec grinding ability
chewing forage difficult
reduced protein, phosphorus and fiber digestion
What might we feed geriatric horses?
many do well on grass or grass-alfalfa pasture or hay supplemented w/ oats - plus dental care, edible oil or rice bran can be added if need more calories
Why might we feed thin horses with a BCS lower than 4 a senior ration?
Better quality/more protein
ca and P content adjusted for changes in digestibility in older horses
pellets (ground) and extruded (improves digestibility)
roughage/stem length to stimulate gut motility
Feed 2-4x/d
What is equine metabolic syndrome?
genetic predisposition “thrifty horses”
ic adipositu, insulin resistance, hyperinsulinemia - respond to high carb foods w/ exaggerated inc in insulin and high BG lvl w/ slow return to normal
Nutritional strategies - restrict dietary carb lvls, restrict total calories to promote weight loss, methods to reduce NSC, promote optimal BCS, “work” for their food
What is pars pituitary media dysfunction
PPID, equine cushings
EMS may be predisposing factor, but both disorders can occur concurrently in middle-age to older horses
Metabolism of starch difficult
Medical strategy:pergolide
Nutritional strategies: avoid overfeeding, but encourage proper BCS
High-fat senior diets provide energy w/o overwhelming carb lvls
What is hyperlipemia?
fasting ponies, donkeys and mini horses
poor quality/decreased feed during high-energy periods (preg, systemic dz), liver dysfunction/failure
Neg energy balance > mobilization of fatty acids > inc hepatic triglyceride synthesis > fatty infiltration of liver
What are small equids and what nutritional characteristics are different from horses?
ponies, mini horses, donkeys
Diff metab than horses
greater fat release from adipose tissue in response to dec insulin
much more susceptible to hyperlipeia if fasted
never starve a pony/donkey/mini
How gave we give nutritional support to starving equids?
reverse neg energy balance
inc serum glucose conc
promote insulin release
inhib mobilization of peripheral adipose tissues
enteral and/or parenteral nutritional support may be necessary
What happens with starvations?
body reserves of fat/protien used for energy > elyte and mineral stores also dec > if refed: insulin released in response to blood glucose > stims protein synth and movement of elytes and glucose into cells > low blood conc of elytes. P needed for energy prod in cells and delivery of O2 by RBC’s
How can we start to refeed a starvation case?
start on poor to moderate quality grass or oat hay - introduce at 50% of maintenance (based on ideal BW), gradually build up over 10 days to maintenance, then gradually introduce concentrate
monitor blood glucose to ensure euglycemic
feeding carbs before gut flora has time to adap can also result in colic, diarrhea and laminitis
reduce nutrient drains by deworming, blanketing, stable to reduce exercise, make sure no competition for food
How might we feed obese horses?
Reduce weight by decreasing the quality or quantity of the diet
Cut out any grain
Feed lower quality hay, but ration must be balanced
Commercial “complete feed” type pellets based on alfalfa and straw for weight loss - horses can still spend a lot of time eatingduce feed intake is handled much better than starvation, even if more prolonged
Do not dec feed intake below 50% of maintenance to allow slow lipid metabolition, less likely to exceed rate that it can be utilized by peripheral tissues, residual diet provides minerals, carbs, and protein necessary for normal body function
What might we do when feeding obese horses in regards to exercise and feeding times?
exercise: start slow - 30m walk/trot 2-3x weekly, increase steadily
Increase feeding time: sm, frequent eedings, slow-feed hay nets and grain feeders, feed obstacles, feeding order
How might we maintain dietary changes
change diet over at least 10 days
do not increase concentrate by more than 0.5 kg (1lb) a day
Problems from sudden dietary changes - laminitis, colic
WHy might we feed anti-inflam diets?
increasing ratio of omega-3 fatty acids in the diet is anti-inflam
Fish oil is a particularly good source bc the fatty acids, EPA, require less metabolism than plant source omega-3 fatty acids (alpha-linoleic)
Limited conversion of alpha linolenic to EPA
What is good to give as anti inflam supplements as commercial supplements
Flaxseed oil (linseed oil) - typically, add 30mL (an ounce) 1-2 a day, anti inflam and improves coat sheen
Diet for lameness may be anti-inflam and/or contain nutrients found in, or precursors of, cartilage and synovial fluid
Glucosamine
Glycosaminoglycan supplements - chondroitin sulfate
