Class Notes (808,754)
United States (313,251)
AVS 3750 (3)
Lascano (3)
Lecture 1

AVS 3750 Lecture 1: Test 3

68 Pages
Unlock Document

Clemson University
Animal and Vet Sciences
AVS 3750

Horse Nutrition Horse Industry • Very important part of the agriculture scene • An increase in horse research in recent years o More research done on other animals o Mostly related to rights from companies, but most is not available to the public • High quality feeds to keep horses = high feed sales o Huge revenue for nutrition industry o Good opportunities for involvement ▪ Research ▪ Marketing ▪ Sales o Owners of horses are more willing to buy additives ▪ Especially for high performance • High sale prices at public auction o High price of animal for performance Horse nutrition • Rely on digestible energy • Ration requirements taken from other monogastric diets Digestion in the horse • No pre-gastric fermentation o Hind gut fermenter = post gastric fermenter o Colonic ferment ▪ Huge colon (largest component of digestive system) ▪ Also have a big cecum • Digestion in the horse begins in the mouth o Incisors are important for nipping/tearing plant o Parts o Molars are used for grinding feed. o Swine important for extrapolating requirements for horses • Condition of the teeth is important o Horses can develop points on their molars that irritate tongue or cheeks ▪ Floating the teeth ▪ Affects eating Hind-gut fermenters • Horses evolved as grazing animals • Concentrates need some form of processing to aid digestion o SA required for digestion • Best suited to small meals o Now adjusted to larger meals o Small meals = lower incidence of acidosis o Most starch in large meals goes to hindgut  starch spillage ▪ Can lead to acidosis • Most digestion and absorption: S and L intestine o Large intestine for fiber ▪ In ruminants digested in the rumen ▪ In horses, digested in hindgut  VFA used as source of energy o Protein associated with fiber is not able to be accessed by animal before the hindgut ▪ Fractions of protein (A, B1, B2, B3, C)  B1-C is not accessed by horse at stomach or small intestine  Synthesize microbial protein at hindgut • Excreted  Not uncommon that horses are deficient in protein practice copophragy • Eating feces to get some of the protein that was synthesized in the hindgut • Digestion of starch, protein and fat in the SI results from the action of enzymes produced by the horse o Most protein excreted o High fat decreces fiber digestibility Colonic Fermenter vs. Cecal • Colonic can eat more and have higher rate of digestion • Cecum can consume as much but break down more and have longer digestion time Provide high quality hay and forage so protein is broken down in SI • Need fraction A  SP Fermentation • The large intestine contains microbial populations similar to those in the rumen of sheep & cattle • The primary function of the microbial population is to digest fiber found in common horse feeds • Acetate can be utilized for energy immediately or can be used for fat synthesis o Not in ruminant (mostly lipogenic precursor) o Also for fat synthesis • Propionate may also be used for energy, but it can also be used to synthesize glucose. Starch vs. Fiber • Fiber is necessary part of a horse’s diet o Need fiber = landmark ▪ Background ingredient in horse diet ▪ Older don’t need extra energy from concentrates o Give max fiber and then give supplementation as need ▪ That’s when starch comes into the diet ▪ Starch spillage o Starch digestion in SI is not quite as efficient ▪ Starch spillage ▪ Can cause acidosis, colic, laminitis  Acidosis: build up of lactic acid, drop pH and change microbial fermentation • Drop below five, kill other microbes and only digest starch ▪ Don’t want readily available starch at the hind gut ▪ What is the extent of a nutrient that can be expended at the hind gut? Comparative digestion Horses have smaller stomach because adapted to consume continuously Nutrient requirements • Water o More important in high performance horse o Replenish electrolytes lost by sweat • Dehydration and electrolyte balance o Can add salt at .5% DM of diet o Also add K o Preventative electrolyte therapy: ▪ IV infusion or Oral infusion before specific high endurance activity  3 day events o Trace minerals ▪ Have to add micro minerals to diet  Not a lot of info on this  Based on other animals  Affect performance • Copper is important because main micro mineral affecting synthesis of cartilage o Important for active horses White sweat: • Latherin • Assist in heat distribution • Horse’s pelt is waterproof o Loss of heat would not happen without it o Allows animal to cool down • Glands to secrete Nutrient requirements Most horses will consume about 2.5 to 3.5 kg of water for every kilogram of feed dry matter. Don’t expend much energy to manage body temperature • 16-24 degrees centigrade • THI: temperature humidity index • Thermoneutral environment Mares peak on milk production @ 2 months Need high quality water due to microbial sensitivity Energy • E requirements expressed Mcal of DE • 3 levels of DE intakes used to adjust for differences in activity & temperament • For mature, nonbreeding, idle horses: Minimum; Average; Elevated Easy keeper vs. hard keeper affects diet Lysine essential for horses Carbohydrates • 1-1.5% BW in fiber • Majority from structureal • Nonstructural ~.5% BW • At maintenance, horses may derive the majority of their daily energy requirement from the digestion of fiber in LI • Fiber digestion alone is not usually sufficient to meet needs of lactating, growing, or exercising horses. o Look at more energy from concentrates Crude Fiber and DE relation of commonly fed feeds Still use crude fiber as opposed to detergent system due to limited research • Oats is most common forage • Barley is also really carbon for energy carbohydrates • Corn silage may be used also Comparison of energy and crude fiber • Feed more alfalfa for more crude fiber over energy • Beet pulp/citrus pulp used for starch replacement o Have more soluble fiber  pectin o Advantage of pectin has relatively high amount of energy released ▪ Not affecting the starch spillage ▪ Pectin stops fermenting when pH is below 6  Starch digested to pH of 4  Fiber cannot be digested lower than 5-6 Carbohydrate digestion • Small intestine o Enzymatic digestion breaks alpha likages o Absorb glucose • Cecum and colon o Microbial fermentation ▪ Break alpha and b bonds o Produce VFA ▪ A, P, B Produce Lactic Acid from starch Nutrient digestion in horse mostly carb. Fraction C  lignin protein in fraction A (SP) digested at small intestine • most protein in supplement needs to come from readily available concentrates o meals o linseed meal: essential fatty acids even though not a good AA profile • high quality hay also digested at SI sugar and starch undergo enzymatic digestion at SI • glucose absorbed • starch spillage o produce lactic acid Horse do not have a gall bladder • Limit amount of fat • Bile used to emulsify fats, so cannot consume that much fat • Can consume 20% fat if on grazing situations to consume constantly o Feed 2 or 3 times a day fat will affect digestion of fiber Some concerns when feeding soluble CHO • pH • Lactic acid • Laminitis o Inflammation of the lamina o Toxins released at pH below 5 ▪ Cause release of histamines and inflammation in the hoof • PSSM o Polysaccharide storage myopathy ▪ Horses with PSSM cannot store glucose as glycogen  Store as glucose  Have other problems in terms of trying to get rid of it  No access to glycogen for bodily processes  In this case, replace non structural CHO with fat • Insulin resistance o Problem related to high degradability of CHO and fiber digestion • Fiber digestion DE in feed related to how fast they are broken down • Replace some of the oils w/ What influence DE requirements • Addressed by NRC o BW, age, growth rate, milk production, pregnancy, level of activity ▪ Weigh, suckle, weigh for milk production • Other factors o Digestive and metabolic differences o Health status o Climate and environment o Variation of digestibility and nutrient availablility o Interrelationships among nutrients Different classes of horses • Mature, idle • Early gestation • Late gestation (11 mos) • Early lactation • Weanling (6 mos) • Yearling • Light work • Intense work [look at tables for energy requirements] Where do horses get DE? • Carbs, fats proteins • GE, DE and ME differs • Energy from nutrients can be o Immediately available after a meal o Stored for later use Use BCS in horses but have 1-9 Protein • Most AA requirements extrapolated from swine • On maintenance, P requirement can be met by medium quality forage o Measured by TDN o Forage Q of 55-60% TDN = maintenance requirement for idle horses ▪ Supplement w/ increased activity/production ▪ Need fraction A form or supplemented by meals Horses vs. Ruminants • Ruminants rely on MCP o 70% P requirement by MCP • horses most MCP is excreted out b/c made in hindgut o need to feed protein with Essential AA that can be digestion at SI ▪ understand graph w/ color boxes o don’t want to use protein for energy Alfalfa quality w/ age Broodmares: need more protein sources added because it is not stored well in the body • Especially during early lactation and just before breeding season for high performance o maintenance of the mare's body tissues o deposition of fetal tissues o milk production ▪ The conversion of dietary protein to fetal or milk protein is not very efficient ▪ Mare's milk = 2.0% protein 500-kg mare =15 kg of milk/d = ~300 g Protein in Milk ▪ Conversion is not very efficient ≈1,450 g of dietary CP 12% CP Can P be used as energy? Technically yes, but energetically expensive • Amino acids must be deaminated first • Releases ammonia – excreted in urine o Costs energy • Carbon skeleton is converted to energy-producing intermediates o Costs energy • Not metabolically efficient energy source • GE is similar to CHO • BUT DE, ME and NE much lower Limiting AA for horses • Body needs EAA • Limiting E imits protein synthesis o Need lysine 1 st nd o 2 Threonine or methionine NPN • Crystalline amino acids  Lys, Meth, Threonine  Often added to feeds for young horses  Reduces total CP by increasing limiting AA  May help reduce environmental impact o Excess protein and N • Urea  High in N (46%)  Can be toxic in horses o Absorbed in SI very readily o Little to no nutrition benefit to horses Minerals: every animal needs a specific mineral mix if its not provided in the base diet • Development of bone quality is more important for athletic purposes o Equine bone is about 35% Ca and 16% P ▪ Deficiencies or imbalances in dietary Ca and P can affect bone development and quality ▪ High levels of P can impair the absorption of Ca  P is antagonistic to Ca  Make sure that that Ca:P is 2:1 o Highest in growing horses and lactating mares ▪ Lactating mares need Ca for milk production  Especially early to peak • Microminerals o Iron is used in the formation of hemoglobin, which is involved in oxygen transport in the body ▪ Allows the transport of oxygen ▪ w/o will not allow transport of oxygen ▪ low iron = anemia ▪ provided in most forages o Iodine is necessary for formation of the thyroid hormones, which regulate basal metabolism ▪ Affect basal metabolism, hormone formation o Copper is involved in cartilage formation and development, of particular concern in growing horses ▪ Highly active animals need commercially fortified feed with copper (20-30 bpm) ▪ It is common for commercially manufactured fortified concentrates to contain at 20 to 30 mg copper/kg DM. Vitamins • Vitamin D and vitamin K are of the least practical significance in horse diets o Vitamin D from sunlight if on pasture ▪ Need to supplement if enclosure o Microbes synthesize vitamin K (same that synthesize vitamin B) • Vitamin A is produced when the cells in the small intestine metabolize beta-carotene o Animal is grazing on good quality forages ▪ Don’t need much vit A o Actively growing pasture is one of the richest sources of beta- carotene in horse diets • The microbial population in the large intestine appears capable of synthesizing B vitamins Forages • Want to maximize forage intake and have good quality • Should receive 1-2.5% Kg of good quality hay per 100Kg BW/d o Pasture should be utilized whenever possible Protein quality • Concentrates: 50-60% of protein is digested in SI o Horse is hind gut fermenter, no microbial protein synthesis o Meals have high protein content ▪ Rapeseed or canola meal have high methionine o Lysine is most limiting AA and most grains are high in lysine ▪ Corn is not • Grass vs. legume: legumes have higher lysine o 20-30% protein digested in SI o don’t provide enough protein from forages, make sure that the rest of the protein requirement comes from good quality concentrates • barley o popular horse feed o energy content is intermediate to corn and oats ▪ good in between • wheat and rye o not really used o sorghum or milo is used commonly ▪ lower concentration of energy than corn ▪ but for corn and sorghum, need to make sure they are processed in some form  steam flake, ground  feed hole, will have limited capacity for breaking down before absorption • beet pulp: o relatively high soluble fiber content o decrease amount of energy with this feed, so need higher intake • soy hulls o good soluble fiber but energy level is lower • rice bran: o high concentration of fat ▪ 15% EE ▪ can supplement some deficiencies associated with feeding high soluble fiber ▪ feeding high amounts of fat is limited due to no gall bladder Protein supplements • SBM has excellent protein quality and is readily available • CSM and linseed meal can also be used but both are slightly lower in protein quantity/quality o Gossypol has not been reported to be toxic in horses ▪ Toxic for ruminant ▪ Varieties of cotton with low content of gossypol but not bad for horses o Linseed has omega 3 so gives coat a shine but doesn’t have good AA profile o Want to have no more than 20% diet of these supplements • Milk products are excellent protein sources, but usually • more expensive than soybean meal o Milk protein sources are rarely used in rations for mature horses, but are often included in foal feeds o Some high performance horses get most protein from this ▪ Race horses, jumpers ▪ Increase muscle development Manufactured feeds: most feeds are commercially mixed since most people do not have access to small amounts of meal or forages etc. • Most will have feed additives for improved digestibility and growth o Monensin is toxic to horses o Cannot use the same as ruminants o Most manufacturers offer at least three separate formulations ▪ One is formulated for horses at maintenance or light work and usually contains about 10% to 12% CP ▪ A second product is formulated for performance horses, broodmares & yearlings.  It contains 13% to 14% CP ▪ A third, formulated for lactating mares, weanlings & ▪ yearlings, contains 15% to 16% CP  And the highest level of vitamin and mineral fortification. NRC Guidelines • Maintenance  depends on maturity • Work (light, moderate, heavy, very heavy)  increases protein requirements • Breeding  pregnant? stallion • Lactation  stages of lactation • Growth  age, target ADG, activity • New classifications?  18 and older (geriatric) horses Maintenance: • Sedentary: not growing, lactating, pregnant or ridden often o Know weight and formulate ration to maintain • Performance requirements: tissue turnover (muscle gain, tissue repair), sweat loss o Energy requirements ▪ Light = ~20 Mcal/d ▪ Moderate = ~23 Mcal/d ▪ Heavy ~27 Mcal/d ▪ Very heavy ~34 Mcal/d Light: western and English pleasure, trail, equitation, hacking Moderate: dressage, ranch work, roping, cutting, barrel racing, jumping Intense: race training, polo, cutting Breeding: gestation requirements • more embryo transfers, AI, in vitro breeding vs. not breeding = increase requirements by 20% Lactation requirements • peak milk production at 3 mos • wean at 5-6 mos o % above maintenance ▪ 1 mo = 244% ▪ 2mo=243% ▪ 3mo=233% ▪ 4mo=222% ▪ 5mo=211% ▪ 6 mo=200% o provide extra nutrients from a starter when peak milk starts to decrease Growth requirements • Maintenance, ADG, stage of growth • High quality protein sources recommended o 60% of more CP should be high quality o especially if low quality forages, low soluble protein ▪ want to avoid low quality after weaning • supply protein in smaller, more frequent meals o more than 2X/d feedings ▪ 4x/d good because will increase protein absorption due to more available source entering gut frequently o promote AA absorption in SI o more study needed ▪ a lot is based on what we know from other species different breeds brings in different requirements and so need to know mature BW of the animal to find ADG and right requirements for specific growth Geriatric Horses: 18+ • more and more relevant w/ owners that have old horses • 7.5-20% of the equine population • not used for slaughter and feed for humans o mainly humane purposes in America o used for food in other countries • considerations o environment ▪ more controlled ▪ susceptible to disease o feeding protocols ▪ more processed feeds ▪ moist o BCS ▪ Can be 1 or 2 ▪ Poorly maintained animal o Nutrition o Dentition ▪ Cannot chew well ▪ Feed specific feed more available for digestion o Fiber digestion: ▪ Affects the horse because the microbe population is not as active in the hindgut ▪ Fiber digestion is decreased so need to decrease amount in ration ▪ Don’t want to have less than 33% in a healthy horse  Geriatric ok w/ 10% forage in diet o Vitamin absorption: ▪ Form of the vitamin ▪ Normally provided in pastures ▪ Now need to be substituted o Kidney function: ▪ Pastures provide too much protein and cause impacted kidney o Liver function: ▪ Reduced productivity so need higher available energy o Feeding: ▪ Soaked feeds ▪ Palatability ▪ Specialized feeds o A lot of horses don’t have these because they are disposed of in different places ▪ Responsibility of owning a horse and providing specific requirements Which category has the highest requirements? • Lactating and high intensity working horses Forages 4/5/2017 2:19:00 PM Familiarize with common terminology and forage species Determine backbone forage for grazing systems in the SE Identify optimal compliments to backbone forages Assess potential benefits and risks of common forages Pastureland • land devoted to the production of indigenous or introduced forage for harvest primarily grazing. Pasture land generally must be managed to arrest successional processes o single or multi crop (rotation for maximized nutrient utilization of the plant o avoid successional process: don’t want to have more unwanted plants (weeds) come into the pasture Rangeland • land on which the indigenous vegetation is predominately grasses, grass-like plants, forbs, or shrubs and is managed as a natural ecosystem. Often a semi-arid region. If plants are introduced, they are managed as indigenous species. o Manage the natural ecosystem Forages • Edible parts of plants, other than separated grain, generally above ground, that can provide feed for grazing animals, or can be harvested for feeding • Of primary importance to domestic ruminants/horses • Commonly referred to as forages or roughages • Main Categories: Grasses and Legumes o Grasses have higher fiber than legumes but lower protein o Legumes fix nitrogen so have increased protein ▪ Alfalfa has great nitrogen fixing ability  Bacteria that form nodules at the root level • Greater than 18% NDF and less than 70% TDN o 80-90% TDN in grains Basic Differences • Two basic types of photosynthetic processes in plants produce differing intermediate compounds o C3 process produces a three-carbon compound o C4 process produces a four-carbon compound • Anatomical features of C3 & C4 plants differ, and they are adapted to different climatic conditions • HIGHER YIELD: C4 plants grow better at hot temperatures, with root systems extending deeper into the ground, and are better adapted to conditions of water stress. Summer growth o Adapted to warm climates • HIGHER QUALITY: C3 plants store more carbohydrates & can then draw on their reserves when they start to grow again. Spring/Fall growth o Adapted to cool season regions Annuals, Biennials and Perennials • Annual o One year, harvested immature, typically harvested for grain i.e. small grain haylage/silage, corn silage, sorghum silage, sorghum-sudangrass silage o Need to replant after harvest every year • Biennials o Brassica spp, (turnips) grazed the first year while vegetative o Last for 2 years • Perennials o multiple year life span Blue= C3 Red = C4 Forage options • upper piedmont and mountain ranges o Backbone: • Tall Fescue with or without a clover o Supplements: ▪ Warm Season Perennial Grasses  Bahiagrass  Bermudagrass  Natives? o Cool Season Annual Grasses and Clovers ▪ Cereals, annual ryegrass, crimson, arrowleaf, ball clover, vetch o Warm Season Annuals ▪ Millets ▪ Sorghum-sudan ▪ Crabgrass • Lower piedmont, Sandhills, coastal plain, peedee regions o Backbone: ▪ Warm Season Perennial Grasses  Bahiagrass  Bermudagrass  Natives? ▪ Supplements:  Cool season grasses: • Tall fescue • Cereals and annual ryegrass  Warm season anuals • Millets • Sorghum sudan • Crabgrass Bermuda grass • Warm Season Perennial • Standard hay crop in SC and Southeastern US • High yielding but needs high fertilization • Decent quality (mid 50s-mid 60s TDN%) • Foundation of horse and beef hay markets and relatively common in dairy rations o Protein deficiency seen with excess Bermuda so need to supplement alfalfa • 3-4 cuttings per season o harvest for hay or silage o 3-4 cuttings/rotations if using for grazing also Bahiagrass (warm season grass) • Typically seen from coast to lower Piedmont • Slower to establish than Bermuda grass • Denser sod o Treading resistant and grazing tolerant • Longer grazing season • Tolerant of low fertility and pH • Lower producing Cool season perennial grasses • Tall fescue o Well adapted for Piedmont o Only adapted to heavy soils in low country o Palatability can be an issue in mixed stands ▪ Rate palatability from 1-5  Usually fescue is about a 2 o Highly persistent after establishment under moderately heavy grazing o Fescue toxicosis: causes lower palatability ▪ Fungal Endophyte causes toxicosis (endo-inside, phyte- plant) ▪ Inter/intracellular contamination  ergot alkaloids cause problems in animals ▪ Friendly endophyte doesn’t cause toxicosis and is less prone to contamination ▪ Symptoms of tall fescue toxicosis  Reduced intake  Vasoconstriction  Increased core body temperature  Increased respiration  Lowered heart rate • Can have heart failure with enough consumption  Altered fat metabolism • Increased fat deposits in muscle  Immunosuppression  Reduction in serum prolactin  Reduced pregnancy rate  Reduced weight gain and milk production  Horse: prolonged gestation length, dystocia, thickened placenta, agalactia (low production of milk) • Orchardgrass o Will persist in upstate for about two years under ideal grazing ▪ Less productive than tall fescue • Timothy and KY Bluegrass NOT an option Nutrient Profile of Forages • Protein: o Legumes > cool season grasses > warm season grasses o Fertilization can increase CP and mineral concentration in grasses and legumes ▪ Hypocalcaemi
More Less

Related notes for AVS 3750

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.