Post on 24-Dec-2015
Equine Nutrition & Feeding
Peggy M. Auwerda
Time-Budgets
Feral Horses
Select highest fiber, lowest protein content
70% of its day foraging
Stabled Horses
10% of their day feeding
Meal fed
Digestive TractThe Mouth- first part of digestive system.
Mouth has 2 main functions- masticate food and wet food with saliva.
Mastication•Jaw sweeps 60,000 times/day when grazing•Saliva contains little, if any amylase
Stomach –
9-15 liters
Trickle feeders
Transit time <2 hr
Cardiac sphincter does not relax to allow regurgitation
Digestive Tract
Digestive TractSmall Intestine
30% of digestive tract40-50 litersTransit time – 45 min to 8 hrsα-Amylase – low & varies widely between horses
Starch digestion occurs in the stomach and small intestinesAmino acids and fat digested and absorbed in small intestineVitamins/minerals absorbed in small intestine
Hindgut – 60% of digestive tract capacityCecum –
25-35 litersTransit time < 5 hr
Large Colon50-60 liters
Small Colon18-19 liters
Large & small colon transit time 48-72 hoursFiber digesters most active pH of 6.2-6.8Starch digesters prefer pH 5.2 – 6.0
Digestive Tract
Aspects of The Foal GI Tract
Small digestive tract
The small intestine does not increase in length from 4 wks of age
Cecum not fully functional until 15-24 mo of age
The large intestine increases with age even up to 20 yrs
Microbial Fermentation
Fibrous &Non-Fibrous
Carbohydrate
Microbe
Volatile Fatty Acids
Gas
B-vitamins & Vit. K
MetabolizedFor
Energy
WastedEnergy
Protein and Amino Acids?
StarchStarch is an important and valuable component of the equine diet.
Equine athletes need carbohydrates for efficient energy use.
Mares need carbohydrates to help produce healthy foals.
Mares need carbohydrates for milk production.
0102030405060708090
Starch Fats Protein SmallIntestineDigestion
LargeIntestineDigestion
Comparison of Corn and Oats
Corn
Oats
%
Postprandial Cecal pH Change
6.6
6.8
7
7.2
7.4
7.6
2 3 4 5 6 7
OatsCornHay
Starch OverloadStarch not digested in SI is delivered to hindgut for bacterial fermentation. Too much starch may…
Cause radical changes to hindgut flora
Increase VFA & lactic acid concentrations – hindgut acidosis
Cause laminitis, colic, endotoxemia, metabolic acidosis, behavioral problems (wood chewing)
Critical capacity for hydrolysable carbohydrate overload ~0.4% of BW
Cuddeford, D. 1999; Harris et al. 1999
How hindgut acidosis can occur in hindgut and how it can be attenuatedHigh Grain or High Fructans
Minimal decrease in pH
Significant decreaseIn pH
Increase in VFA&Lactic Acid of
Hindgut
Time ReleasedBuffer
Optimal VFA absorption
Optimal Energy forWorking & Breeding Horses
Decrease in fiber fermenting OrganismsIncrease in lactate producing organisms
Very low pH
Bacterial lyses
SubclinicalAcidosis
Irritation & damageTo intestinal mucosa
Inhibition of fiber fermentingOrganisms & lactateUtilizing organisms
Off FeedDecreased fiber
digestibilityColic Symptoms
Stereotypic Behaviors
Release of endotoxins
LaminitisPagan, J. 2007. Feedstuffs
Total CHO
Non-FiberCarbohydrates
Neutral DetergentFiber
NonstructuralCarbohydrates
Neutral DetergentSoluble Fiber Hemicellulose
Acid DetergentFiber
Sugars
Starches
Pectins
Fructans
β-Glucans
Cellulose
Lignin
Carbohydrates
Ingredient NSC Sugar StarchPectins
Beta-Glucans
% DM -------------------------- % of NSC ---------------------
Alfalfa hay 23.0 0.0 40.9 33.0
Grass hay 17.2 35.4 15.2 49.4
Barley 61.8 9.1 81.7 9.2
Corn 71.4 20.0 80.0 0.0
Oats 42.4 4.4 95.6 0.0
Wheat 73.8 8.9 80.2 10.9
Distillers 10.3 0.0 100.0 0.0
Corn gluten feed 24.7 3.7 71.2 25.1
Corn gluten meal 17.3 0.0 69.4 30.6
Soyhulls 14.1 18.8 18.8 62.4
Soybean meal, 44% 34.4 25.0 25.0 50.0
Wheat midds 31.2 10.0 90.0 0.0
Starch Comparisons (what’s low, what’s high)
Methods Of Maximizing Starch Digestion In Small Intestine
Properties of the starch granuleGrain processingPlant cell wallsTransit time through the small intestineAvailability & concentration of enzymes
REMEMBER!“The number one cause of deaths from
colic is from starch overload due to
feeding mismanagement.”Dr. John Reagor, PhDChief of ToxicologyTexas Veterinary Medical Diagnostic Laboratory
Glycemic Response Hyperglycemia occurs after
digestion of grain meals Affects substrates utilized
during exercise
Glucose & insulin peak 60-90 min after a meal Insulin promotes fat storage
Sugary meals before exercise will CHO to muscle & ↓ fat oxidation
Feed intake usually expressed as % of Body Weight Lbs feed/100 lbs body weight Free Choice
Forages – Maximize in the rationProvide fiber & energyMin. at least 1% of body weight (dm basis)
ConcentratesProvide energy
Supplements Provide protein, minerals and vitamins
Feeding Horses
Estimating Weight (lbs)
Heartgirth (in) x Heartgirth (in) x Body Length (in)
330
Body Condition Score Measures amount of body fat (1-9 scale)Determines balance between energy intake & expenditureSimple, repeatable, consistent methodComparison between animals
EnergyDetermines Weight & Condition Of Horse
Body Condition ScoreFat laid down in predictable patterns
Organs
Behind the shoulder
Ribs
Rump
Back
Withers
Head and Neck
Body Condition Score Evaluation
Visual assessment and actual touch
Palpate fat areas
Avoid mistaking longer hair covering for fat areas
Avoid being fooled by conformation differences
Body Condition Scoring1-3 Poor-Thin4 Can see ribs,
vertebra ridge evident5 Back flat, can’t see
ribs, but can feel them6 Crease down back, fat
deposits7-9 Fleshy - Extremely fat
Time & Additional Grain Required To Improve
BCS by 1 level
Improving 1 Condition Score
Days Needed Daily Gain Additional Grain Needed
60 0.75 lbs/day 4.5 lbs/day
90 0.50 lbs/day 3.0 lbs/day
120 0.40 lbs/day 2.3 lbs/day
Optimum Body Condition ScoreEach horse has its own ideal condition for the breed & use
Average horse 5-6
Broodmare 5-7
Breeding stallion 5-6
Performance horse 4-6
Building a Horse RationStart with horse needsMaximize forage Add energy if neededAdd protein & minerals if neededConsider adding vitamins & supplementsConsistency is key to good feeding practices
Feed concentrate that makes-up the difference between nutrients needed & nutrients in roughage
Forages are the FoundationPasture, Hay
GrassBromegrassOrchardgrassTall FescueTimothy
Grain HayOat HayWheat hay
Straw
LegumeAlfalfaBirds Foot trefoilCloversLespedeza
Ingredients Used In Place of Hay for Roughage
Good Quality Sources:
Beet Pulp
Soybean Hulls
Dried Citrus Pulp
Dried Apple Pectin Pulp
Alfalfa Meal
Poor Quality Sources:
Peanut Hulls
Oat Hulls
Ground Straw
Cottonseed Hulls
Rice Hulls
Rice Mill Feed
Forage Isn’t Everything
Most do not have all the minerals &/or vitamins a horse requires. Four ways to add these.
1. Add 1 to 4 oz mineral or mineral/vitamin supplement per day or
2. Add 1 to 2 lbs ration balancer (mineral plus protein) per day or
3. Feed 5 to 7 lbs fortified grain per day or
4. Feed 12 – 14 lbs complete feed (forage & grain)
Energy Sources - Grains
Oatsvariable
crimped vs. whole
Corncracked, steam rolled
Barley
Sorghum & wheatless than 30%
rolled, cracked, flaked,
Fat/Fatty Acids• No gall bladder
Horses can be safely fed up to 20% fat in the total diet Energy from fat is 90% utilizable
Often used to supplement calories for hard-working horses and hard keepers
Reduction in DM intake & bowel weight
Calmer temperament
Protein
Muscle & bone growth, milk production, fetal growth, normal metabolismMost horses requirements can be met with good quality hay or pasture forage
Protein Quantity = amount
Quality = amino acid balance
Very important for young horses
Lysine, methionine, tryptophan most limiting for growth & milk production
Sources of Protein for HorsesSoybean Oil Meal
Flax - Linseed Meal
Sunflower Meal
Cottonseed Meal
Peanut Meal
Corn Gluten Meal
Whey
Dried Skim Milk
Minerals Content in the diet
Determined by soil & waterQuality of feed & proportion of grain to hay
Macro-mineralsCa & P - quality forages usually provide adequate amount
This ratio is very important: 1.5:1 to 2:1 Grains are rich in P and low in Ca
NaCl (Salt)Salt block will meet many horse’s needsIf horses sweat a lot - need salt in the ration
Trace MineralsLook for iron, zinc, copper, selenium
MineralsMacro-minerals
– Ca & P - quality forages usually provide adequate amount
This ratio is very important: 1.5:1 to 2:1 Grains are rich in P and low in Ca
– NaCl (Salt)Salt block will meet many horse’s needsIf horses sweat a lot - need salt in the ration
– Trace MineralsLook for iron, zinc, copper, selenium
A guide to the recommended
concentrations of trace elements in
the diet, mg/kg dry matter. (Modified
fromthe NRC 2007).
These will need to be adjusted to suit
individual circumstances, growth rate and
appetite etc.
Vitamins
Fat soluble: - stored in body - A, D, E, K- Toxicity’s can occur if fed in excess
Water soluble: - must be continuously supplied - B-complex; niacin, thiamin, riboflavin
Vitamins
High quality fresh forages = High quality fresh forages = maintenance for mature horses maintenance for mature horses
Hay is poor in Vitamin AHay is poor in Vitamin A
Supplement Vitamin A in the rationSupplement Vitamin A in the ration
Exposure to sunlight provides Vitamin DExposure to sunlight provides Vitamin D
Guide to recommended levels of Fat-soluble vitamins (need to be adjusted according to individual
circumstances).
Nutrient Requirement Varies With Class of Horse – NRC 2007
Adult (no work)
Working
Light exercise
Moderate exercise
Heavy exercise
Very heavy exercise
Stallions
Pregnant Mares
< 5 mo
5th, 6th, 7th, 8th, 9th, 10th, 11th mo
Lactation1st, 2nd, 3rd, 4th, 5th, 6th mo
Growing 4, 6, 12 mo18 mo
Light exerciseModerate exercise
24 moLight exerciseModerate exerciseHeavy exerciseVery heavy exercise
Water Essential for all body functions
Temperature regulation
Feed digestion
Amount of water intakeLevel of exercise
Ambient temperature
Quality of feeds in ration
Proportion of diet that is forage
Minimum 1 gallon/100 lbs BW/day
Maintenance Size: body weight
Environment
Individual differences
Dry matter intake: 1.5% of the BW
Most - energy requirements are met with forage alone
Recommended Daily Feed Intakes as % of Body Weights
Class Forage Concentrate Total Example
1,000 lb horse
Mature (Idle) 1.5 - 2.0 0.0 - 0.5 1.5 - 2.0 15-20 lb
Geriatric 0.8 – 2.0 0.5 – 2.0 1.5 – 3.0 15-30 lb
Geriatric Horses Nutrient Considerations
Reduced salivation
CF digestibility ↓
Total fiber < 30%
CP digestibility ↓
10-14% CP
Energy:
Increase soluble carbohydrates, fats, & oils
Caloric Restrictions
Supplement minerals & vitamins including vitamin C
Selection of Feed For the Geriatric Horse
Highly palatable
Easy to chew & swallow
Forage - chopped, cubed, pelletized, or in a wafer
Grains - rolled, crimped, or flaked
28 yr old horse
32 yr old horse
Feeding The Athlete
Aerobic and Anaerobic Metabolism
During exercise, ATP is generated from breakdown of:
Glucose
Fatty acids
Amino acids
ATP low in muscles; essentially no storageContinuous ATP production vital for athletes
ATP
OxidativeMetabolismLactate
Free Fatty Acids
Creatine Phosphate CO2and
Water
Lipolysis
O2
Simplified Energy for Muscle Contraction
Pyruvate
Blood Glucose
Muscle Glycogen
Work
ENERGY, ENERGY, ENERGY!
Levels of Performance/Work
Light – Recreational riding, beginning of training programs, Show horses (occasional)
Moderate – School horses, Recreational riding, Show horses (frequent), Polo, Ranch
Heavy– Ranch, Polo, Show horses (frequent, strenuous events), Low-medium eventing, Race training (middle stages)
Very Heavy – Racing, Elite 3-day event
Performance/Work
Energy =
Activity DE (Mcal/d)
Maintenance 16
Light 20.0
Moderate 23.3
Heavy 26.6
Very Heavy 34.5
Feeding Guidelines for Performance Horses
Starch is necessary for replacing glycogen stores.Hay
Feed at least 50% of total ration as forage (pasture &/or hay)Preferably high quality grass hay or alfalfa/grass mix
Exercising horses do not need high levels of proteinMore important – quality of protein
Horses should be fed to meet their immediate needsCut grain on rest days
FAT SUPPLEMENTATION
Enhanced stamina capacity for uptake & oxidation
of fatty acids in muscle Concomitant decrease in use of
endogenous carbohydrate stores - Muscle glycogen sparing
Add 6-10 weeks before performance
Feeding Guidelines for Performance Horses
Hay requirementFeed at least 50% of total ration as forage (pasture &/or hay)Preferably high quality grass hay or alfalfa/grass mix
Exercising horses do not need high levels of protein
More important – quality of proteinHorses should be fed to meet their immediate needs
Cut grain on rest days
Breeding AnimalsMaiden mare
Barren mareFlushing- Increasing energy intake 20-25% ~3 wks prior to breeding.
Gestating mare
Lactating mare
Stallion
•Last 3 month of gestation: 60 % foals’ weight•Mare needs to gain 0.3 – 0.8 lb/d
Gestating Mares
Lactating Mare
Lactating Mare
Month 1 – 3 = milk is 3 % BW
Month 4 – 6 = milk is 2 % BW
Requirements of energy, protein, mineral, and vitamin double vs. maintenance
21
22
23
24
25
26
27
28
15 30 45 60 90 120 150
Time (days)
Dai
ly M
ilk P
rodu
ctio
n (lb
s)
Feed Consumption (% BW)
Mare status Forage Concentrate Total
Early pregnancy 1.5-2.0 0-0.5 1.5-2.0
Late pregnancy 1.0-1.5 0.5-1.0 1.5-2.0
Early lactation 1.0-2.0 1.0-2.0 2.0-3.0
Late lactation 1.0-2.0 0.5-1.5 2.0-2.5
•Adding concentrate to late pregnancy mares accounts for limited energy & acclimates microbes
•Allow 1 wk to 10 d for mares to adjust to intake changes•Heavy milkers may require as much as 1.75-2.0% of BW in concentrate feed/day
Body Condition ScoreMaximum Reproductive Efficiency
Moderately fleshy to fat mares can be expected to
Cycle earlier in the yearHave fewer cycles per conceptionHave a higher pregnancy rateMaintain pregnancy more easily
Mare prior to breeding should have a BCS of 6 or greater and fed to maintain weight.BCS of 5.0 is marginal especially for lactating mare.
Feeding The Growing HorseGoals
Maximize genetic potential for growth
Sound musculoskeletal system
•Nutrient Balance is important•Requires higher quality feeds•Growth rate & age determines requirements•Growing till reach 30 months
Average Daily Gain
0
0.5
1
1.5
2
2.5
3
3.5
0 2 4 6 8 10 12 14 16 18 20 22 24
Month of Age
Avg
. Dai
ly G
ain
, lb
s/d
Rations should be balanced to promote a consistent growth curve
Requires periodic updating of the ration
Nutritional Strategies Aimed at Minimizing DOD
www.Foalcare.com
Nutritional Strategies Aimed at Minimizing DODFeed selection
High quality forage is a must
Grain mix concentrates formulated specifically for growing horses
Improper use of supplements
Feed amounts
Forage
Minimum of 1 lb / 100 lb BW / d
Fed to appetite is best
Concentrate
~ 1 lb / 100 lb BW / d
Max. 8 to 10 lbs /d
Monitor The Growth Process
Daily Intakes
Body Weight
Average daily gain
Signs of Skeletal Abnormalities
Physitis
Joint effusion
Lameness
Feeding Guidelines & Strategies To Minimize Risk Of Hind Gut Dysfunction
Know Your Horse & Provide Feed Based on:
Class
Stage of production
Age
Activity level
Growth
Consider..Quality of feeds available
Body Condition
Feeding Guidelines & Strategies To Minimize Risk Of Hind Gut Dysfunction
Check for Refusals Change type &
amount of feed gradually. 7-10 d period
Provide Salt
Feeding Guidelines & Strategies To Minimize Risk Of Hind Gut Dysfunction
Feeding Guidelines & Strategies To Minimize Risk
Of Hind Gut DysfunctionControl amount of NSC (sugar, starch & fructan) the horse consumes. Minimize the flow of fermentable polysaccharide to the large intestine
Feed starch sources little and often i.e., less than 5g oats/(2g starch)/kg body weight/mealPre-feed forages
Feeding Guidelines & Strategies To Minimize Risk
Of Hind Gut DysfunctionMinimize the flow of fermentable polysaccharide to the large intestine
Limit rate of concentrate intake through physical obstructionMaximize substrate (glucose) availability to the performance horse
Ensure good occlusion of teeth through regular dentistry
Group Feeding Should Account for Dominance Hierarchies
Recognize Feeding-Related Behavior Problems
Feeding Guidelines & Strategies To Minimize Risk Of Hind Gut Dysfunction
REINSRelevant Equine Intensive
Nutrition Software
Peggy Auwerda & Garland Dahke
REINSTotal mixed ration (TMR) program that allows for evaluation and formulation of protein, energy, vitamin and mineral requirements of horse rations across multiple stages of production Based off of the 2007 NRC Nutrient Requirements of Horses Written in MS Visual Basic and uses MS Excel as the user’s interface to operate
REINSLeast cost formulator can be used or rations can be entered manually Extensive feed library – Up to 220 feedsMultiple feed libraries can be created which allows a use to assign a feed library to a farm Comprehensive appendixes