Lecture 4: Equine Nutrition Flashcards
What is function of stomach
Enzymatic breakdown
What is function of SI
Digest rapidly available carbohydrates and readily accessible protein
Where do horses obtain most of their protein
Directly from food during digestion in foregut
What is the function of the cecum
Some carbohydrates and proteins in the cell wall of plants will escape digestion in SI and move to hindgut for fermentation.
Where cellulose is broken down
What is the function of the colon
Reabsorption water and some further fermentation
Are horses foregut or hindgut fermenters
Hindgut
Where does microbial fermentation occur and what does it allow for
Occurs in cecum and colon and allows horses to breakdown cellulose
Fermentation in hindgut produces __, ___, and ___ which are absorbed through intestinal wall
CO2, methane, and VFA’s
What is used for glucose production
Propionate
__ is converted to acetyl CoA and used for immediate energy or for fat synthesis
Acetate
Butyrate is also converted to ___
Acetyl CoA
Hindgut digestion is largely ___ and not ___ as in foregut
Microbial, enzymatic
What are some disadvantages relative to ruminants
- Less efficient
- Less dietary nutrients entering hindgut so less microbial growth
- Passage through hindgut is rapid so less fermentation
- Less efficient at absorbing vitamins and proteins
- Protein present in microbes is not digestible and thus lost
What % of BW should horses consume in water
5%
How many gallons per day should horse drink
7 gallons
How much feed should horse get
1.5-3% BW or 15-30lbs
What is main energy source in food
Carbohydrates
How much protein should horses eat/day
550-1000 grams, 12% dry matter
Deficiency in protein can result in __ and ___
Potbelly and poor top line
VFA’s absorbed from hindgut provide about __% of energy requirements
30%
How much vitamin A should horse have
15,000-22,000 IU
What is vitamin A important for
Night vision, reproduction and immune response
Vitamin A toxicity results in what
Bone fragility and tetratogenesis
How much Vitamin D should horses have
3000 IU
What is Vitamin D important for
Calcium homeostasis
Deficiency in vitamin D can result in what
Rickets
Vitamin D toxicity can result in
Soft tissue mineralization
How much vitamin E should horses have
500-1000 IU
What is the main important function of vitamin E
Antioxidant
How much thiamine should horses have
30-60mg
What is thiamine important for
Carbohydrate metabolism and ATP production
Deficiency in thiamine can cause
Ataxia
How much riboflavin should horses have
20-50mg
What is riboflavin important for
ATP synthesis
What macromineral is important in nearly every pathway
Calcium
Calcium must be in a 2:1 ratio with ___
Phosphorus
How much calcium should horses have
20-40 grams
What is phosphorus important for
ADP/ATP production
How much phosphorus should horses have
14-20 grams
What is magnesium important for
Enzyme and muscle contraction
How much magnesium should horses have
7.5-15 grams
What is potassium important for
Cellular regulation/AP
How much potassium should horses have
25-50 grams
What is sodium important for
Cellular regulation/AP
How much sodium should a horse have
10-40 grams
What is chlorine important for
Acid-base and osmotic regulation
How much chlorine should horses have
40-90 grams
What is sulfur important for
Amino acid formation
How much sulfur should horses have
15-18 grams
What is selenium important for
Needed for glutathione peroxidase and thyroid hormone metabolism
How much selenium should horses get
1-3mg
What is zinc important for
Component of many enzymes
How much zinc should horses get
400mg
What is copper important for
Enzymes, connective tissue, mobilization of iron stores
How much copper should horses get
100mg
What is iodine important for
Synthesis of thyroid hormone
How much iodine should horses get
3.5-4.4mg
What is cobalt important for
Cecil and colonic microflora need cobalt to synthesis vitamin B12
How much cobalt should horses get
0.5mg
How much iron should horses get
400-500mg
What is iron important for
Myoglobin, hemoglobin, and cytochromes
How much manganese should horses get
400-500mg
What is manganese important for
Carbohydrate and lipid metabolism
What microminerals are often deficient in many American pastures/hay
Selenium, zinc, copper
How much dry matter should make up horses diet
90-93%
What is neutral detergent fiber
Includes indigestible lignin and fermentable fibers
What is acid detergent fiber
Estimate of poorly digestible fiber portion-;Ig in and cellulose
How much acid detergent fiber should make up horse diet
25-30%
If ADF is in low ___ it might be insufficient indigestible fiber for hindgut health and if > ___ would be bad
Low 20’s, greater than 45%
What are water soluble carbohydrates
Sugars and all fruit ans
What are ethanol soluble carbohydrates
Includes sugars and short chain fructans
T or F: entire diet can be complete pelleted diets no need for additional forage
True
What are some examples of complete pelleted diets
Senior feed, Estrella Larkin life, alfalfa, beet pulp
T or F: ration balances must be fed wit forage
True
What is a ration balancer
Vitamin/mineral supplement combined with protein and fat formulated at 1-1.5lbs daily
What are some examples of ration balances
Purina enrich or omega match, Kentucky equine research all phase
What is a good light work concentration
Safe choice
What is a good moderate work concentrate
Purine strategy, omelene 200
What is a good intense activity concentrate
Purina ultium or nutrena perform
T or F: grains must be fed with forage and add calories only
True
What is the maintenance requirement for calories
30-35kcal DE/kg
Fiber fills ___% BW daily so for 1000lb horse how much is minimum intake
1.5%, 7.5kg or 16.5lbs
What is gestation length for mare
11 months
What are the maintenance calories for mare < 5months pregnant
30-35kcal/kg/day
What are the maintenance calories for mare > 5months pregnant
66kcal/kg/day
What % BW is mare expected to gain during gestation
12-15%
What % BW gained in pregnant mare is foal vs fluid
9.7% is foal, rest is placenta/fluid
__ restriction during last 90 days resulted in normal foals, longer gestation
Energy
What are the maintenance calories for lactating mare
36kcal DE/kg
What is average milk production
2.3-3.8 k milk/100kg BW
What is the energy content of milk
450-580 kcal/kg
What are the nutritional needs for a 6 month old foal (45% of adult weight)
210 kcal/kg
What are the nutritional needs of 1 year old foal (65% of adult weight)
151 kcal/kg
What are the nutritional needs of a 18 month old foal (78% of adult weight)
151 kcal/kg
What are the nutritional needs of 2year old foal/adult
30-35 kcal/kg
What are the nutritional needs of light working horse (1-3hrs/week)
40kcal DE/kg
What are the nutritional needs of moderate working horse (3.5hrs/week)
46kcal DE/kg
What are the nutritional needs of heavy working horse (4-5hrs/week)
53kcal DE/kg
What are the nutritional needs of very heavy working horse( 1 hour speed work or 6-12 hrs/week)
63kcal DE/kg
What are some common diseases caused by inappropriate nutrition
Vitamin E deficiency, selenium deficiency, nutritional hyperparathyroidism
What are some common diseases treated with nutrition
Insulin dysregulation, HYP, PSSM
What are some diseases caused by vitamin E deficiency
- Equine degenerate myeloencephalopathy (EDM)/ neuroaxonal dystrophy (NAD)
- Equine lower motor neuron disease (EMND)
What is normal vitamin
E level
> 2ug/ml
What is marginal vitamin E deficiency value
1.5-2ug/ml
What is deficient vitamin E level
1.5ug/ml
What are some clinical signs of EDM and NAD
Symmetric ataxia and paresis of trunk and limbs
What are some clinical signs of EMND
Trembling in antigravity muscles, sweating, recumbent, pedestal stance, constantly shifting, no ataxia, elevated tail head
What is the treatment for diseases caused by vitamin E deficiency
5000 IU natural source vitamin E daily (RRR-alpha-tocopherol)
What is white muscle disease (nutritional myodegeneration)
Acute myodegenerative disease of cardiac or skeletal muscle due to selenium deficiency
What is treatment for white muscle disease
Selenium supplementation
What is the ideal diet for insulin dysregulation/equine metabolic syndrome
water soluble carbohydrates +starch= structural carbohydrates <10% ideal
What causes nutritional secondary hyperparathyroidism
Horses fed diets low in calcium, high in phosphorus
What happens in nutritional secondary hyperparathyroidism
Excessive PO4/low Ca2+ diet reduces intestinal Ca2+ absorption and results in hyperphosphatemia
Facial bone loss with excessive accumulation of subperiosteal unmineralized connective tissue resulting in facial enlargement
How do you treat nutritional secondary hyperparathyroidism
Maintain normal serum calcium, ratio should be Ca:PO4 is 2:1
What is the pathogenesis of grain overload
Ingestion of large amount of carbs overwhelms the small intestine and enters the cecum/colon
Results in rapid fermentation by gram positive lactic acid productive bacteria and decreases cecal pH
Large number of gram negative bacteria die releasing endotoxin resulting in ileus
What are some clinical signs of grain overload
Colic, abdominal distention, laminitis, trembling, sweating, diarrhea, toxic membranes, tachycardia, and gastric reflux/ileus
What is the cause of osteochondrosis dissecans
- Found in young horses that have rapid growth and failure of endochondral ossification
- Nutrition: diets very high in energy or have an imbalance in trace minerals (low copper diets)
- Inherited predisposition
What is the treatment for osteochondrosis dissecans
Feed a complete diet low in carbs, remove the chip
What is the pathophysiology of HYPP
Repetitive depolarization of muscle cells due to faulty pump
What are some clinical signs of HYPP
Fasciculations, prolapsed third eyelid, tetanic contractions, recumbent, stretorous breathing, death from respiratory failure
What is the treatment for HYPP
Limit daily intake of potassium to <1% of diet
What is the largest source of potassium in horse diet
Hay up to 3%
What food would be ideal for HYPP horse
Grain, because has <0.5% K+ and grain also releases insulin which facilitates K+ uptake into cells
What is the pathophysiology of polysaccharide storage myopathy (PSSM)
Single base pair mutation in the GYS1 gene, resulting in large stores of abnormal glycogen
How do you manage PSSM
Low carb diet <14%, high fat diet (6%), daily exercise (enhances glucose utilization, improves energy metabolism in skeletal muscle)
Myth or fact: alfalfas high protein causes kidney problems
Myth
Myth or fact: High protein is not harmful to kidneys, however extra protein is metabolized to ammonia which must be excreted by kidneys. To handle this extra demand horses will drink more water and make more urine
Fact
Myth of fact: alfalfa high protein makes a horse hot
Myth
Myth or fact: For reasons that are not clear, some horses are more energetic when being fed alfalfa but it isn’t the protein
Fact