Equine Nutrition Flashcards
What do horses eat?
Grass- good for digestion
Hay/ Haylage - Provides fiber (satiates + gi motility working) particularly in cooler months when pasture is unavailable.
Fruit and veggies- add moisture to feed
Concentrates: concentratead energy source
Salt : good to offer to help replenish electrolytes.
What is a horses daily water requirement?
Variable due to age, activity, physiologic state, temp
Typically = kcal requirement.
0.3-0.8 gallons/100 lb/ day or 25-70 ml/kg/day
What is a horses drinking behavior?
- Usually small volumes each time
- 2-3 drinks per bout
- Higher demands horses will drink more times, but normally not more drinks
- If frequency is restricted, may increase drinks, volume is constant.
Insufficient water intake in horses will cause?
- Dehydration
- Colic
- Poor performance
- Impaction
What can be causes of insufficient water intake?
- Broken equipment
- Poor quality, dirty, unpalatable water
- Water with high particle count > 6500 mg/L is not palatable.
What can grow in stagnant water? What can this lead to?
Stagnant water can grow blue green algae
Could leaad to liver necrosis, tremors, diarrhea and even death.
Hepatotoxicity
What is a horses daily energy requirements? What % dry matter would allow horses to meet their daily requirement on good quality forage? What is their max DMI consumption per day?
Daily energy requiremet: 33 Mcal/100kg BW/day
Daily needs DMI on good quality forage -> 1-1.5 % BW DMI
Max consumption DMI: 3-3.5 DMI
What is a horses normal diet composition?
~ 80 % energy
- 8-14.4 % protien
- 2-3 % minerals
~ 1% vitamins
What is the term for poor energy intake? What can it lead to?
Starvation = poor energy intake
Can lead to:
- Fat catabolism
- Catbohydrate store depletion
- Once fat is depleted- protien catabolism.
What can fat catabolism cause>
Spares protien,
- Can lead to hyperlipidemia
- Increased risk in overweight horses/ ponies
- Can occur in illness, during lactation
What occurs in protien catabolism?
- Catabolism of liver protien
- Decreased plasma protien (edema/ ascites)
- Poor immunity, skin, respiratory and cardiac functions
- Skeletal muscles spared as long as possible ( needs to be spared for fight or flight)
What is the risk with refeeding a starved horse?What can you see with this? How can you do it safely?
- The horses can get refeeding syndrome, this risk is high in emaciated horses. Clinical signs are diarrhea, neurological signs.
Prevention: - During refeeding use small portions of high quality forage offered at frequent intervals ( Q 4 hours) to stabilize insulin.
- Use energy intake to promote weight gain, DER.
- Diet suggestion: Combo of molasesses- free alfalfa product, good qyality soft leafy hay (early cut), good vitaminh and mineral supplement.
What other considerations are there for neglected horses?
Many neglected horses have endo and ectoparasites, dematophytes (fungal infections) other wounds.
In what conditon SHOULDN’T you feed ad libitum?
If body condition score is very low.
What can be helpful to give to starved horses in terms of diet quality and composition?
• Could be helpful to provide a higher
protein diet (similar to growth)
unless contraindicated by
concurrent disease
• Make sure diet provides vitamins
and minerals as needed
• Watch for food aversion, difficulty in
prehension or chewing
What are the protien requirements for horses? How is protien analyzed?
Protien is often analyzed as nitrogen x 6.25 ( nitrogen is 16% of protien)
- Protien requirement is really essential amino acids + nitrogen requirement that is used as building block to synthesize non essential amino acids.
- Mature horse, relies on colonic conversion of Nitrogen to synthesize essentila if there is enough dietary N.
- Foals, reproductive mqares, and other physiogical demanding life stages rely on combination of essential AA from diet and colonic production.
What are protien requirements of horses dependent on?
- age
- Physiological state
- Activity
- Feed intake
- Digestibility
Where can energy be from if there is is poor feed intake? in horses
In case of poor feed intake amino acids may be oxidized for energy.
What happens to hay that is heated or gets wet? What is the Maillard reaction?
Hay that is heated or gets wet decreases in protien digestibility.
Maillard reaction is a reaction between priotiens and sugars. This will change color and taste but decrease digestibility.
What is Non protien nitrogen? Is it a good source of Nitrogen in the horse?
NPN such as urea is not useful in
the horse as it will be absorbed in
the small intestines and excreted as
urea in the urine
• This is unlike foregut fermenters
where the bacteria can utilize the
nitrogen BEFORE it is absorbed in
the SI
• If the feed contains urea, it should
be subtracted from the crude
protein analysis (which is nitrogen
analysis)
• NPN is less toxic in horses than
foregut fermenters
What occurs with protien deficiency?
Usually accompanied by overall
energy malnutrition
• Weight loss
• Poor skin/hair quality
• Poor growth
• Decreased lactation (mares) • Poor performance
• Biochemistry:
• Low BUN
• Low albumin/TP
• Edema possible
What occurs when a horse has excess protien? What kind of process is protien metabolism?
• Rare
• Increased heat production
• Protein is thermogenic
• Can be a problem in hot climate or
during performance
• Can lead to ammonia smell in
the urine
• Expensive
• Could lead to obesity?
• Possibly increased growth in
juvenile horses?
- Protein metabolism is thermogenic, so their could be increased heat production in preformance horses.
What are easily digested in the small intestines. What breaks down starches and carbohydrates, where are they absorbed in horses? What can excessive carbohydrate intake lead to?
Carbohydrates - Starch and sugar are easily digested in the small intestines
• Amylase breaks down starch and carbohydrates are absorbed in the brush border
- Excessive carbohydrate intake can lead to GI dysbiosis
- Colic
- Laminitis
- Diarrhea
Why is fiber important horses? What is important about soluable fiber? Insoluable fiber?
Fiber is essential to regulate GI motility and provides substrate for the GI microbiota.
Soluble fiber
• acts as substrate for the microbiota
• Usually results in increased stool water
content
• Pectin, gums
•Insoluble fiber
• Lower digestibility
• Cellulose, hemicellulose, lignin
• Produces volatile fatty acids that are
absorbed (70% compared to ruminants)
What are the fat soluable vitamins?
- Vitamin K
- Vitamin A
- Vitamin D
- Vitamin E
What are the essential fatty acids? How do horses get these fatty acids? What percent of fats are in their meals and when may it be preferable to highly digestable carbs?
• Essential fatty acids: linoleic acids
and arachidonic acid • Horses can form these FA, so not
necessary from the diet • Fats are 2-6% of the meal (DM)
usually
• Can be increased up to 10% (20% of
the daily kcal) gradually with a
palatable oil
•Also add vitamin E
• May be preferable to highly (Due to risk of oxidation)
digestible carbohydrates when
energy demands are high
• Less risk of colic and laminitis
What percent of minerals in the body accounts for calcium and phosphorus? What is Phos important for? What is calcium important for? What is the storage pool for these minerals and how does the blood level remain constant ?
• Calcium and phosphorus comprise
70% of all the minerals in the body.
• The bone is the storage pool for
these minerals (the ionized calcium
in the blood remains constant by
drawing from the bone if needed)
• P is important for energy
metabolism (ATP), membrane
function and enzyme regulation
• Ca is important for neural function,
enzyme activity, cell signaling etc
What can occur when there is excess phophorus or oxalates in certain grasses? Where is calcium absorbed?
- Can bind calcium and can have implications on skeletal health in growing foals and mares.
- Calcium is mostly absorbed in
the small intestines whereas
phosphorus is mostly absorbed
in the large intestines
What is the recommended ratio of Ca to phosphorus in mature horses? What impacts absorption of the other more?
- Excess phosphorus impacts calcium absorption more than the other way around
- The recommended ratio (Ca:P) is 1:1 -5:1 in the mature horse
What is important to note about horses and salt?
• Horse has an appetite for salt and will consume adequate amounts if it is available
What can occur with excessive salt intake? What can cause eating of excessive salt? What are the signs/risks of salt toxicity?
Excess salt intake -> drinking
more water -> more urine
• Horses confined to the stall may eat salt out of boredom, may drink more and urinate more
• Wet stall
Salt toxicity - if water is not available or palatable.
- colic
- diarrhea
- weakness
- neuro signs
What is the treatment of salt toxicity?
Slow ingestion of saline free water?
If too rapid, cellular edema can occur
- Neuro signs
What can occur in salt deficiency?
• Uncommon as long as salt is
available
• May cause weakness
• Decreased sweating
• Decreased performance
• Decreased sweating
• Decreased lactation
• Pica
What is potassium important for? What is it dependent on?
Important for normal cardiac function, acid base balance, renal function, neural function.
Dependent on activity and physiologic/ Pathologic state.
What can occur with low potassium? What can casue it?
Is high potassium due to diet common?
hypoklemia can cause: Inappetence, fatigue, weakness, lethargy.
Can occur with excess sweating (increased aldasterone secretion, increased Na+ retention, increased potassium excretion), diuretics, diarrhea.
What does magnesium metabolism adhere to? How likely is dietary deficiency reported? What else can cause deficiency?
- Closely adheres to calcium and phosphorus.
- Dietary deficiency is uncommon, high P may reduce absorption as well as hypomagnesemic tetany.
What can occur with hypomagnesemic tetany, how can you treat it, and who is more susceptible?
Can cause paralysis of limbs, grass tetany is example.
Treatment: Magnesium and Calcium supplementation.
More susceptible: Lactating Mares, Fasted animals in transport, animals exposed to young pastures or K+ enriched pastures.
What is Mg necessary for?
Adenyl cyclase activity, which is required for parathyroid hormone release. ( Which is important for absorption of calcium)
What can occur with Iodine pathologically? Is it during excess or during deficiency?
Paradoxically, both excess and deficiency can cause clinical signs of hypothyroidism.
What are the symptoms and mechanisms occuring with low iodine? High iodine?
Iodine is important to make triiodothyronine and thyroxine.
Low iodine -> low thyroid hormone production
Excess iodine -> negative feedback for TSH release from pituitary -> Low thyroid hormone production.
You can also see Goiter and hypothyroidism in these patients.
What are clinical signs of hypothyroidism?
- dry coat
- alopecia
- impaired growth
- decreased bone mineralization
- Lethargy, inappetence.
- Cold intolerance
- Goiter (swelling of thyroid gland)
What is copper an important cofactor for? What does it do on its own? What can occur in excess?
Copper is important as a cofactor for Super Oxide Dismutase (SOD).
Copper promotes oxidation on its own.
Copper excess can cause liver and renal damage.
What are the functions of copper?
– Collagen/ elastin synthesis (dematuration)
– Iron mobilization (deficiency-> anemia)
– Melatonin synthesis (reddening of black hair coat
What can be seen in patients who are near soil with high molybdenum content?
It inteferes with copper absorption and can cause copper deficiency
What is Zinc a cofactor for? What can occur with Zinc excess? Zinc Deficiency?
• A cofactor to many enzymes including SOD therefore an antioxidant • Zinc excess is uncommon, but zinc can interfere with copper
absorption
• Zinc deficiency
• Parakeratosis in the lower limbs
• Decreased food intake
What can occur if foals are exposed to excess zinc?
In foals -> excess may cause joint disease
What supplementation is given to race horses and foals and can be harmful to the foal? What can it cause?
• Iron deficiency is uncommon
• Supplementation: given to race-horses and foals
• Can be harmful in foals and is unnecessary (can cause liver
failure in foals)
What occurs with Vitamin E and Selenium?
Synergistic effect as antioxidants (low amounts in one require
supplementation of the other)
• Prevent lipid peroxidation in the cell membranes- glutathione
peroxidase
What is present at the catalytic site of glutathione peroxidase?
Selenocysteine
What can cause white muscle disease?
Vitamin E and Selenium deficiency
What are the clincial signs of white muscle disease?
Clinical signs
• Lethargy
• In foals- unable to curl tongue to suckle
• May cause aspiration pneumonia – if tracheal muscles are affected
Yellow fat disease- a condition that causes steatitis
Steatitis- inflammation of fat stores.

What can you see that will lead you to a diagnosis of white muscle disease?
- Low Vitamin E concentration ( plasma levels can be variable)
- Can biopsy liver and muscle stores (avoid fat stores, they are not reliable)
- High Creatine Kinase, and AST (shows recent muscle damage)
- Low RBC glutathione peroxidase (selenium deficiency)
What is the treatment of white muscle disease? What can be a potential issue?
• Selenium and vitamin E can be given prophylactically by
muscular injection to foals at birth
- Supplement in creep feed (feed Offered to nursing foals)
- Supplement the mare’s feed
• Vitamin E excess is uncommon (could reduce absorption of
other fat-soluble vitamins
Toxicity is potential issue -> 5-10x requirement is toxic (narrow safety range)
Wheere can you find Vitamin E in the food? What occurs with storing, heat processing or when you have high oil diets?
- High in leafy greens.
- Usually sufficient in fresh pasture
- Storage can cause degradation/oxidation
- Heat processing can cause degradation
- Diets with high fat/oil- increased vitamin E requirement to prevent oxidation.
What are the fat soluable vitamins? Where can they be found in general in adequate amounts. What can occur with storage? What is the issues with Fat soluable vitamins, and supplementation?
- Fat soluble vitamins A, D, E, and K
- Generally present in adequate amounts in feed
• Although can be reduced if stored for long periods - Greater risk for toxicity especially for vitamins A and D due to slow rates of excretion
- Fat soluble vitamins share the same absorption mechanisms and can compete with each other
What is important about water soluable vitamins? How can they be obtained? How are they removed? What can increase the requirement?
• Water soluble vitamins are rarely deficient or in excess
• Can be synthesized endogenously
or by colonic microbes • Excess is filtered in the urine and excreted from the body
• Requirement can increase if water intake is high or high energy requirements
What can you use to supplement vitamins? When would additional vitamin supplementation be beneficial?
- Grain mixtures are usually fortified with vitamins
- High energy-> be careful with over-supplementation (can be Expensive)
- Additional vitamin supplements could be beneficial if:
- Hay/ feed quality is poor or stored for long
- Colic/GI disease -> dysbiosis (less bacterial microflora so less synthesis of vitamins so supplements are important.)
- Antibiotics -> dysbiosis (destruction of gut microflora)
What are equine probiotics? Do we use them? Why?
• Species that are commonly found in human probiotics or yoghurt
include Lactobacillus, Bifidobacterium and Enterococcus are only 1%
of the normal equine GI flora
• Firmicutes are most abundant, but not used in most commercial probiotics • Most equine GI disease affect the large intestines so if bacteria does not
survive it won’t be useful • Probiotics may not be safe in very young horses (<2 mo)
• Most evidence suggest that some probiotic Lactobacillus strains may
survive the GI tract, but do not colonize it • Little evidence of probiotics in horses at present (especially in healthy
horses)
What is important about feeding a stallion? What would need to be avoided? When may you need to increase the concentrate?
Feed to maintain an ideal BCS
• May need to increase amount of concentrate in breeding (showing off for female)
• Avoid obesity- poor fertility
(poor sperm quality when obese)
What is an important BCS for gestation? What are common nutritional issues during this time? When is it important to increase food intake?
Maintain BCS of 5-6 • More issues with under nutrition rather than over nutrition • No increase in food intake necessary until last trimester (week 16) of pregnancy
How much should you increase the feed of the mare during her final trimester? How much weight should a Quarterhorse or thoroughbred gain during pregnancy?
During last trimester increase 12-20% in intake
• For Quarterhorse/ Thoroughbred mares an expected increase of 150-200
lbs. in bodyweight during pregnancy
What would the protien requirement be in first trimesters and the last? Why does that change? What is a good feed for a pregnant mare? What can you balance the feed with?
Protein requirement would increase to 8% in the first trimesters and 10% in
the last trimester. this is because more protien is needed in the final trimester to produce the fetus’ tissues and help support lactation.
- High protein feed: legume grass, legume hay
- Can balance a meal with grass hay and high protein grain (12% protein DM)
What is the increase in protien requirements in the lactating horse? How can you balance that diet, and how much grain protien is needed to give the correct amount of protien?
- Protein requirements increase to 13%
- Can be balanced with a combination of legume hay or legume grass
- If legume hay is provided, grain protein can be 12%
- If grass hay is provided, grain protein needs to be at least 16%
What is important about the calcium content of grass hay and legume hay and how does it affect lactating mares?
• Grass hay is lower in calcium so may need to supplement
• Legume hay has enough calcium, but may need to supplement
phosphorus
What is important for the diet requirements of the suckling foal? What is creep feed? What does it include?
• The main diet is the mare’s milk; however will show interest in other
food such as the mare’s grain and creep feed
• Creep feed: the feed that is offered to suckling animals (also beef,
swine, small ruminants) to support growth in addition to milk
• Creep feed would typically include corn, oat, barley
When would most foals begin to wean? When would you start introducing creep feed?
Most foals would wean between 3 and 7 months.
You would start to introduce creep feed at 1-3 months.
What is the ideal BCS for a weanling foal?
4/9
What are potential orthopedic issues in foals in there potential causes?
- Could be the result of accelerated growth
- Genetic trait
- Common conformational abnormalities:
- Toe in
- Straight fetlock
- Nutritional factors: excess and/or deficiency
- Vitamin A
- Vitamin D
- Calcium
- Phosphorous
- Mg
- Copper
- Zinc
- Other Causes
- Energy excess: Above 120% the requirement according to the NRC
- Protein excess? No evidence in foals (or dogs)
- Carbohydrate excess?
• Increased insulin secretion- Affects growth plate structure
What are important ways to prevent foal orthopedic disease?
Prevention:
- Maintain an ideal BCS (4/9)
- Ideal growth rate estimates:
- Suckling foals <1.1 kg per day
- Weanling foals <0.75 kg per day
- Prevent rapid growth
- Early intervention as needed
What is the ideal BCS for a horse at rest/ maintenance? What is their Daily energy requirement?
What about a performance horse?
What about a horse who completes ranch work?
Rest / Maintanence: 4-6 (0.33 x kg bodyweight)
Performance: 5-6 ( 1.4 x (DER for rest))
Ranch work: 4-5 (1.6 x (DER for rest))
What is the ideal BCS of a halter competition/ pleasure horse? What is their daily energy requirement?
What about a race competition horse (3 day events)?
Halter Competition/ Pleasure Horse: 5-6 (1.2 x (DER for Rest))
Race Competition (3 day events): 4-5 (1.9 x(DER for Rest))
What is included in the diet of performance horses?
- Combination of carbohydrate sources:
- Legume grass, green grass, and grains [high energy]
- VFA
- Oils [10% dry matter] 20% of all energy intake
Protein:
• Protein requirements are increased in performance horses
• Protein is thermogenic
• Can negatively affect performance in warm weather • $$$
• High protein feed: alfalfa (legume hay), grass hay, oat hay, grain
What can occur if performance horses are given too much protien durring warm weather?
This will decrease performance
What should you not do in terms of grain, when feeding performance horses?
Do not feed more grain than forage.
What occurs with performance horses when they have high amounts of activity? What electrolytes should we be concerned about and what sources of electrolytes can we provide?
• More activity -> more sweat-> more electrolyte loss
- Electrolytes of concern: Na, Cl, K, Mg, Ca
- Legume hay provides Ca, Mg, K but low in Na
- Grains- do not provide much electrolytes
- Salt blocks
- Added salt if sweating for over an hour 1-2 oz per hour
What is the quantity of water a performance horse will typically drink, and what can affect that?
- Water: 30-40 L per day (depends on temperature and activity)
- Higher requirement if main diet is dry hay rather than pasture/forage
- Water needs to be clean
- Restrict access is horse is hot/water too cold ( to prevent colic)
- 2-3 L every 15-30 minutes
What can donkeys eat that is not advised in horses? Why?
- Able to feed on lignin-rich, low energy food- Slower GI transit allows increased fermentation
- Evolved to survive in a semi-arid mountainous environment
- Forager
What is the difference of energy requirements in donkeys than in horses? What occur if donkeys are fed with horses?
• Energy requirements are also lower than horses (50-70% of a similar size
horse)
• Can become obese and develop hyperlipidemia, laminitis and other metabolic
complications if fed with horses
What would a donkeys typical diet contain?
- Typical diet would include wheat or barley straw or stover (leaves and
stalks of crops such as corn)
• Straw can be fed ad-lib - Low energy density
What is important to keep an eye on in donkeys? What do pregnant or lactating Jennys need along with growing donkeys? What is the concern with feeding concentrates?
Dental health- important as they consume very high fiber food
• Pregnant or lactating jenny (female donkey) and growing donkeys require
supplementation with higher energy and protein feeds
• Alfalfa • Beet pulp • Rice bran
• Supplementation feed should be given in small amounts and mixed with
straw
• Avoid concentrates in donkeys- high risk for laminitis and colic
When should H2O be available for donkeys?
- Water should be available in all times when possible
- While donkeys are quite resilient and resist dehydration, this is not recommended
DON’T DEHYDRATE DONKEY
DDD
What is included in a typical nutritional assesment of horses?
Full medical history
- Housing/environment- inspect if possible
- Reproductive history
- Detailed diet history
- What is being fed, how often, any supplementation
- How is the feed offered
- Feeding behavior
How can you determine body weight of horses?
- Bodyweight can be measured on walk-in scales or estimated:
- Lb Bodyweight= Heart girth (in)2 X Length (in) /330
- Kg Bodyweight= Heart girth (cm)2 X Length (cm)/11800
- Heart girth – measured behind elbows at expiration
- Length- point of the shoulder to tuber ischii
What are some lab tests that can be run on equine patients? What would they indicate in terms of diet?
Most nutrients cannot be adequately determined with lab
tests/blood tests
• Albumin- can be reduced if protein status is poor, acute inflammation
or liver failure
• Albumin half life is long (19.4 days) therefore may not reflect acute
changes
• Decreased creatinine/BUN can indicate poor muscling and protein
intake
What is important to look at when assessing feeds?
- Physically assessing feed: appearance, smell
- Feeds should be in sealed container
- Appropriate temperature and moisture
- Oil- sealed, protected from light and high temp
- Hay- protected from rain/moisture
- Alfalfa – inspect for toxic blister beetles (sometimes present)
- Hay – leaf to stem ratio
- First cut is less digestible, and leaves are smaller (less nutritious, more legnin)
• Second and third cut- richer and more digestible, longer leaves
- Hay quality – color (bright green is best; dark brown not good); mold (take core sample and send for testing to get representative sample)
- Weigh the feed (not volume) (volume can be misleading)
- Estimate pasture/grass intake
- Can send a sample to lab analysis
What is Rhabdomyolysis - Monday Morning Disease? What horses do you see it in? What is the result of this disease?
- Rhabdomyolysis is damage/destruction of muscles
- Usually the result of extreme exercise and excretion
- Especially in race-horses- Thoroughbred, standardbred, Arabian
- Results in severe muscle damage that is extensive enough to have considerable
metabolic implications
What can cause monday morning disease? What other animals can it be seen in?
It is possible that horses on a high fat diet and low antioxidant intake are at higher risk of exercise-related oxidative damage
- Also reported in sled dogs/sporting dogs and wildlife during capture and transport, and in humans
- Can also result for other extensive muscle damage such as trauma, burns, snake bites, electrocution, heat stroke
- Other causes:
- Vitamin E/ selenium deficiency
- Electrolyte imbalance (sweat, heat)
- Underlying disease (fever)
- Polysaccharide storage myopathy-glycogen storage disorder
- Quarter horses - Warmblood - Draft horses
What are the clinical signs of rhabdomyolysis?
Muscle pain
• Swollen muscles
Stiff gait
Myoglobin in the urine may cause red-brown urine
Can progress to renal failure – tubular necrosis due to myoglobinuria
Potassium leakage from myocytes can cause cardiac arrythmia and
even cardiac arrest! (Hyperklemia)
What is the lab values that indicate rhabdomyolysis?
- Elevated serum creatine kinase
- Elevated serum AST
- Elevated serum potassium
- Myoglobinuria
What is the treatment of Rhabdomyolysis?
Supportive care- fluids, adjust electrolytes, antioxidants?
Corticosteroids (if in shock)
Nutritional support:
Feed 1-2.5% BW/day
Limit starch to 10%
Limiting starch not only modifies fuel energy use in the muscle, but it also decreases excitability and nervousness
Increase fats (20-25% DE in fat)
Vegetable oils
Associated with decreased HR “calmness”
High fiber
A commercially prepared high-fiber, high-fat, low-starch diet should be offered on a regular basis
These diets are palatable, nutritionally balanced, and designed to maintain a horse’s weight
- Reduce stress/ confinement
- Allow regular exercise
What is hyperlipidemia? What is the clinical signs? Who is more at risk?
Hyperlipidemia is common in overweight ponies and in mares
Horses may be thin whereas ponies are often overweight
Many times secondary to stress, disease, pregnancy, lactation or poor feed intake
Clinical signs:
Inappetence
Dullness
Depression
Poor feed intake
Colic
Can cause liver failure
What is the pathogenesis of hyperlipidemia? Is it different than in other species?
The pathogenesis is similar with other species:
Free fatty acids are mobilized to provide energy at a rate that exceed their metabolism
(fatty acid oxidation or formation of ketone bodies)
Lipids are re-esterified to triglycerides
May accumulate in the liver where they are metabolized to energy
The fat accumulates in hepatocytes and can also cause clots/emboli in blood vessels
What is the treatment for hyperlipidemia?
Mortality- high
Treat primary illness
If anorexic- feeding tube is indicated to reverse
catabolic state
Insulin- can work with ponies – can stimulate
peripheral lipoprotein lipases
Prevention is key!
Maintain an ideal BCS
Address disease and monitor intake
Provide high quality diet for mares during pregnancy and lactation
What is colic? What causes colic? What are the signs of colic?
Colic is a general name for abdominal pain
- Many possible causes
- If colic is prevalent- check diet, dentition, parasite control
- Impaction colic- usually in the large intestines, often can be palpated
- Can be caused by: Indigestible food, Sand, pica, poor hydration
Signs of colic include:
Pawing
Rolling
Bloating
Sweating
Distress
Uneasiness
Loss of interest in food and water
Peculiar postures (sitting, stretching)
Absence of gut sounds
What is the treatment of colic? what are the different types of colic? What can you do to prevent colic?
Treatment:
Soak food- divide to 3-4 meals
Provide soluble fiber- beet pulp
Wheat bran
Psyllium
Linseed
Provide salt blocks to avoid pica
Flunixin meglumine- reduces the cellular production of prostaglandins but
can also mask signs
Gas colic- in large intestines, can palpate
The result of excessive fermentation and gas production
Can be the result of high energy feeds such as grain, lush forage
Sand colic-
Large intestines- hard to palpate
Suspect according to environment and sand in feces
Prevention:
Access to water
Dental health
Avoid excess grain/high energy forage
Slow transition to diet change
Avoid feeding when horses are ‘hot’ after exercise
Encourage owners to become educated on fed quality, dental care,
vital signs and recognizing early signs of distress
What are important considerations about colic, how can you try to resolve prior to surgical intervention, what other interventions can occur to help the horse improve?
- Equine colic may be considered medical when it can resolve without surgery, or surgical when there is an impaction that does not respond to medical care
Medical treatment is appropriate if the horse is mildly painful and the cardiovascular system is functioning normally
If evidence of intestinal obstruction with dry ingesta is found on rectal examination, a primary aim of treatment is to rehydrate and evacuate the intestinal contents
If the horse is very painful- pain must be addressed as pain can negatively affect GI motility
Address hydration and electrolyte abnormalities if present
A nasogastric tube may be passed to relive gas
What is laminitis?
Laminitis results from disruption of blood flow to the laminae
These laminae structures within the foot secure the coffin bone to the hoof wall
Inflammation often permanently weakens the laminae and interferes with the
wall/bone bond
In severe cases, the bone and the hoof wall can separate

What can cause laminitis? What are the clinical signs?
Etiology:
Can be caused by certain toxins such as bacterial toxins
This can be the result of GI dysbiosis, nutritional factors, or an infection
Excessive carbohydrate intake- incidental grain overload
Grains, green pasture
Gut microbial shift: not all carbohydrate will be digested in the small intestines, fermentation in the large intestines causes acidosis
bacterial die-off and release of endotoxins
Endotoxemia can cause and increase in TPR, colic (within 12-16 hours) laminitis
(within 24 hours)
Clinical signs:
Lameness
Pain
Change in the hoof structure in chronic disease
Can be fatal
What is the treatment and prevention of laminitis?
Treatment:
Stop fermentation- mineral oil, laxatives
Walk/gentle exercise if not painful or too sick
Banamine
Toxin binding medications- antibiotic polymyxin B can be given IV before toxins cross to the blood; di-tri-octahedral (DTO) smectite (Bio-Sponge) under research Prevention:
Avoid high sugar/water soluble carbohydrate feed
Soaking hay in water and then removing the water can help reduce the water-solublecarbohydrate that may contribute to dysbiosis
What is Equine Metabolic Syndrome? What horses are most affected? What is your hallmark sign?
Equine metabolic syndrome (EMS) is a characteristic collection of clinical signs and clinicopathologic changes in equids that places them at high risk for developing laminitis
Insulin dysregulation, the abnormal insulin response to oral or IV glucose is the hallmark of EMS
Most affected horses are obese, but insulin dysregulation can occur in thinner
animals as well
increased regional adiposity in the neck and tailhead regions is typical
Hallmark sign: Hyperinsulinemia with normal blood glucose concentrations
(insulin resistance) is the hallmark finding.
What is the response of a horse with EMS that eats a high carbohydrate meal?
- Horses with EMS respond to high carbohydrate meals with an exaggerated increase in insulin and higher than normal blood glucose that tapers slowly
Associated signs include infertility, altered ovarian activity, and increased appetite
Can also cause hypertriglyceridemia, increased serum concentrations of leptin, and arterial hypertension
While the cause of this syndrome is not entirely known or understood, obesity appears to be an important risk factor
What are potential complications of EMS? What is the diagnosis?
Experimentally, high blood insulin levels lead to laminitis due to vasoregulatory actions
Insulin resistance can decrease nitric oxide production and promote vasoconstriction
EMS may be a predisposing factor for pituitary pars intermedia dysfunction (PPID; equine Cushing’s disease)
Diagnosis: oral sugar test (OST) or oral glucose test (OGT) (fasted for 3-12 hours, then given corn syrup and blood drawn at 60 mins, and 90 mins)
How do feeds affect blood glucose and insulin in the horse?
Glycemic index: the plasma/blood glucose response to ingestion of a measured
amount of feed
The higher glycemic response typically produces a higher insulin response
Corn, oat, and barley all result in increase in blood glucose (BG) within 15 minutes
- The glycemic index of hull-less oats is higher with a more rapid increase in BG (higher digestibility)
Barley is of low glycemic index
Pelleting and extrusion tend to reduce the glycemic index
Grass hay has a higher index than legume hay
What is ration adaptation, and what can you do to prevent the chronic negative implications?
Over time, horses may adapt to high glycemic index foods This results in higher insulin secretion and decreased insulin
response This has chronic negative implications Appropriate diet: reduce high energy concentrates, fats can
be included in small amounts, increase fiber and roughage
Pasture access should be eliminated or severely restricted
until body weight is in the desired range A muzzle could be used to limit feeding Sudden feed restriction should be avoided- risk of
hyperlipidemia/ Hyper TG
What is suggested feeding plan for EMS?
Slow steady weight loss
After weight loss, previously obese horses will likely have lower energy requirements than their lean counterparts.
Exercise – moderate to allow gradual decrease in adiposity
Avoid overexcretion and rhabdomyolysis
What is chronic kidney disease? What causes it? Is it common in horses? And what diet is recommended?
Chronic kidney disease is relatively uncommon in horses
Common causes: high blood pressure, coagulopathies, pyelonephritis and tumors
Renal disease is typically progressive
Unfortunately, no clear diet recommendations- avoid high protein (legumes for example)
Protein < 8%
Carbohydrate based diet
Adequate hydration
What is important about feeding geriatric horses? What issues can horse owners see in geriactric horses? What should you consider in terms of feed types?
Some horses remain physically active and healthy well into their twenties and others become “geriatric” by mid-teens
Older horses may lose weight and muscle mass although obesity is not uncommon
17% of owners reported weight loss in their elderly horse within the last 12 months
If the horse does not have an underlying metabolic disorder, there may be a benefit to a high caloric density and increased protein diet
Consider the use of more digestible forage (less mature grass hay)
Consider including highly digestible fiber sources such as beet pulp/soy hulls as means to increase the energy intake
Soaking and throwing away the water to reduce as far as possible the water-soluble carbohydrate intake as these may contribute to risks for colic and laminitis
What is a good energy source for animals who are not being exercised (in terms of geriatric horses)? How should the food be prepared and what should be avoided?
If there are no contraindications: oil as an energy source rather than cereal starch - especially for those animals not being exercised
If any cereals, other than oats, are fed make sure they are processed by cooking (e.g., steam flaking, micronizing) to make the starch more easily digested, reducing the risk of starch overload
Avoid feeding large grain-based meals: restrict meal sizes
What is important to remember when feeding the critically ill horse?
There are little data on feeding hospitalized horses and its
association or effect on morbidity and mortality
However, plenty of data exists in people and other species to demonstrate that a catabolic state reduces prognosis
Nutritional intervention should be considered if the horse is
not fed for longer than 48 hours in an animal with good
physiological status
Less if obese, underlying metabolic disease, growing or
very sick
Enteral nutritional support: a nasogastric feeding tube can be
passed and used temporarily, or an indwelling esophageal
feeding tube can be placed The horse should be checked for gastric reflux before feeding
What should you look for in the critically ill horse before reinstating feeding schedule?
check for gastric reflux before feeding
What is parenteral nutrition? When is it used? What are its components?
If the gut function is impaired, parenteral nutrition may be
administered
The formula is custom made under a hood
Components used in formulating parenteral nutrition include:
protein in the form of amino acids
carbohydrates in the form of dextrose
lipids in the form of long chain fatty acids
May be safer to avoid in donkeys, ponies and other horses prone
to hyperlipidemia
electrolytes and vitamins
The catheter, line and bag must be kept as clean as possible