Equine Nutrition Randy C. Webb Virginia Tech 2007

Horse Digestive Tract

Review Protein, Carbohydrates, fat, minerals and vitamins are all digested in the small intestine Protein, Carbohydrates, fat, minerals and vitamins are all digested in the small intestine Cecum is a section of the colon where digestive bacteria break down roughage Cecum is a section of the colon where digestive bacteria break down roughage Water is absorbed in the large intestine Water is absorbed in the large intestine

Definitions –Ration – Feed allowed for a given animal during a day of 24 hours, whether it be fed at one time for in portions at different times –Balanced ration – Feed that furnishes the necessary nutrients in such proportion and amount as will properly nourish a given animal for a 24-hour period –Nutrient – Applies to any food constituent or group of food constituents of the same general chemical composition that aid in the support of life –Feedstuffs – Nutrients which are taken into the digestive system –Mastication – Chewing

Definitions  Chyme – Semi fluid mass of partly digested food expelled from the stomach into the small intestines  Carbohydrates – Sugars and starches in feeds used for energy  Fats – Similar to carbohydrates, but contain higher percentage of chemical compounds, thus yielding 2.25 times more energy than carbohydrates  Protein – Any group of complex compounds which contain nitrogen and are composed of amino acids  Vitamin – Essential organic nutrient which is required in only small amounts

Definitions –Minerals – Inorganic matter which aids in skeletal growth and chemical reactions –Epiphysis's – Inflammation of growth plates at ends of long bones; occurs mostly in knees one and two year olds –Rickets – Abnormal bone growth caused by Vitamin D deficiency

So is a horse a Non-ruminant or Ruminant ?

Digestive systems... Enzymatic digestion of carbohydrates, proteins and fats in foregut Enzymatic digestion of carbohydrates, proteins and fats in foregut Limited fiber absorption in hindgut Limited fiber absorption in hindgut Man, pigs, dogs Man, pigs, dogs Fiber digestion in rumen Fiber digestion in rumen Enzymatic digestion in foregut Enzymatic digestion in foregut Minimal fiber digestion in hindgut Minimal fiber digestion in hindgut Cow, sheep, deer Cow, sheep, deer NonruminantsRuminants

So where do horses fit in? Somewhere in between: Somewhere in between: –High rates of enzymatic digestion in foregut (mouth to small intestine) –High rates of fermentive microbial digestion in hindgut (cecum to rectum)

Functions of digestive system include: Prehension of food (grabbing) Prehension of food (grabbing) Mastication (chewing) Mastication (chewing) Digestion Digestion Absorption Absorption Initial nutrient storage Initial nutrient storage

Nutrition What is nutrition? What is nutrition? – Nutrition is a science that studies the relationship between diet and health. What is first thing we need to know ? What is first thing we need to know ? –Body weight and what the horse is used for.

Estimate body weight with... Hearth girth weight tapes or Hearth girth weight tapes or Body weight equation Body weight equation W = Weight HG = Heart Girth BL = Body Length HG squared x BL (inches) W = 330

Why is horse body weight so important? Horses should be fed a percentage of their body weight. Horses should be fed a percentage of their body weight. –Mature, idle and late gestation mares: –Mature, idle and late gestation mares: 1.5 to 2% of body weight –Mares in early lactation and growing horses: –Mares in early lactation and growing horses: 2 to 3% of body weight –Working horses: –Working horses: 1.5 to 3% of body weight

REASONS WHY ANIMALS NEED FEED MAINTENANCE MAINTENANCE GROWTH GROWTH REPRODUCTION REPRODUCTION LACTATION LACTATION WORKING WORKING OTHER PRODUCTS AND USES OTHER PRODUCTS AND USES

WAYS ANIMALS USE NUTRIENTS TO MAINTAIN THEMSELVES Used to keep the body warm Used to keep the body warm Replace old cells Replace old cells Run the internal organs and for body movement Run the internal organs and for body movement

SIX TYPES OF MATERIALS THAT PROVIDE NUTRIENTS CARBOHYDRATES: Major sources are corn, oats, hay, soybean oil meal and grain sorghum. CARBOHYDRATES: Major sources are corn, oats, hay, soybean oil meal and grain sorghum. FATS: Meat scraps, tankage, cottonseed and fish meal are examples. FATS: Meat scraps, tankage, cottonseed and fish meal are examples. PROTEIN: Tankage, soybean meal, legume hay, blood meal, feather meal, fish meal and skim milk. PROTEIN: Tankage, soybean meal, legume hay, blood meal, feather meal, fish meal and skim milk.

TYPES OF MATERIALS (CONT.) MINERALS: Eighteen minerals are needed by animals;six are macro minerals. Includes calcium, salt, phosphorus, magnesium, potassium and sulfur. MINERALS: Eighteen minerals are needed by animals;six are macro minerals. Includes calcium, salt, phosphorus, magnesium, potassium and sulfur. VITAMINS: Vitamins A,D, and the B vitamins are most important in animals. VITAMINS: Vitamins A,D, and the B vitamins are most important in animals. WATER: Most important of all nutrients. A market hog is 40% water; newborn calf is 70% water. WATER: Most important of all nutrients. A market hog is 40% water; newborn calf is 70% water.

The Purpose of the Nutrients Carbohydrates – Supplies Energy Carbohydrates – Supplies Energy Proteins – composed of units called amino acids which are used as building blocks to develop body tissue Proteins – composed of units called amino acids which are used as building blocks to develop body tissue Vitamins – Essential for normal body functions Vitamins – Essential for normal body functions Minerals – Aid in skeletal growth and chemical reactions Minerals – Aid in skeletal growth and chemical reactions Water – used for body’s chemical reactions, regulate body heat, lubricant Water – used for body’s chemical reactions, regulate body heat, lubricant

TWO GENERAL CLASSES OF FEEDSTUFFS ROUGHAGES: Feedstuffs that are high in fiber and low in energy. ROUGHAGES: Feedstuffs that are high in fiber and low in energy. Examples include hay, green pasture grasses and legumes and silage. Examples include hay, green pasture grasses and legumes and silage. CONCENTRATES: Feed that are low in fiber and high in energy. CONCENTRATES: Feed that are low in fiber and high in energy. Examples are corn, oats, wheat, meat scraps, blood meal, soybean meal and urea. Examples are corn, oats, wheat, meat scraps, blood meal, soybean meal and urea.

DIGESTIBLE NUTRIENT A digestible nutrient is the part of a feedstuff that can be digested, or broken down. A digestible nutrient is the part of a feedstuff that can be digested, or broken down. Fiber in roughage is not easily digested. Fiber in roughage is not easily digested. Ruminants and horses are efficient users of roughage. Ruminants and horses are efficient users of roughage.

TERMS RATION: The total amount of feed an animal gets in a 24 hour period. RATION: The total amount of feed an animal gets in a 24 hour period. BALANCED RATION: A ration that provides all of the nutrients needed by the animal in the right amount and proportion. BALANCED RATION: A ration that provides all of the nutrients needed by the animal in the right amount and proportion. DIET: Type and amount of feed and water an animal eats. DIET: Type and amount of feed and water an animal eats.

THREE TYPES OF ROUGHAGE FOR ANIMALS PASTURE- Land where grasses and other plants grow for animals to graze. PASTURE- Land where grasses and other plants grow for animals to graze. HAY- Made of the leaves and stems of plants that have been cut and dried for feed. HAY- Made of the leaves and stems of plants that have been cut and dried for feed. SILAGE- Made from cut green plants by chopping them into small pieces and placing the “chop” in a silo. SILAGE- Made from cut green plants by chopping them into small pieces and placing the “chop” in a silo.

EXAMPLES OF GRAIN CONCENTRATES Grains are high in TDN but do not provide a balanced ration. Grains are high in TDN but do not provide a balanced ration. Examples include corn, oats, wheat and grain sorghum. Examples include corn, oats, wheat and grain sorghum. Corn is the most widely used grain. Corn is the most widely used grain.

SOURCES OF PROTEIN SUPPLEMENTS Protein supplements are high in TDN and high in protein. Protein supplements are high in TDN and high in protein. Three types: Three types: Animal - meat scraps and tankage, blood meal, fish meal, and skim milk. Animal - meat scraps and tankage, blood meal, fish meal, and skim milk. Plant- soybean oil meal, cotton seed meal and various grain by-products. Plant- soybean oil meal, cotton seed meal and various grain by-products. Synthetic- Urea, molasses, rice hulls, and citrus pulp treated with ammonia. Synthetic- Urea, molasses, rice hulls, and citrus pulp treated with ammonia.

FEED ADDITIVES Placed in feed while it is being manufactured to preserve it and enhance growth of the animals. Placed in feed while it is being manufactured to preserve it and enhance growth of the animals. Medications Medications Wormers Wormers Marketing enhancement Marketing enhancement Antioxidants Antioxidants

FACTORS TO CONSIDER IN SELECTING FEED FOR ANIMALS NUTRIENT CONTENT NUTRIENT CONTENT PALATABILITY PALATABILITY FREE OF HAZARDOUS MATERIALS FREE OF HAZARDOUS MATERIALS VARIETY VARIETY BULKINESS BULKINESS COST COST FEED STORAGE FEED STORAGE

THREE FORMS IN WHICH ROUGHAGE IS FED BALES BALES LOOSE CHOP LOOSE CHOP PELLETS AND WAFERS PELLETS AND WAFERS

WAYS CONCENTRATES ARE MADE INTO FORMS OF FEED CRACKING AND ROLLING CRACKING AND ROLLING GRINDING GRINDING EXTRUDING EXTRUDING

WAYS SUPPLEMENTS ARE PREPARED BLOCKS- Salt or mineral block BLOCKS- Salt or mineral block LIQUIDS- Molasses LIQUIDS- Molasses MIXES- Salt, protein sources and other materials MIXES- Salt, protein sources and other materials