Animal Nutrition: Macronutrients and Water

• Nutrition is a branch of biology and the science of feeding animals.
• The nutrition process involves animals ingesting, digesting, absorbing, and using nutrients for maintenance, growth, work, and reproduction.
• Proper animal nutrition results in good health, increased productivity, feed efficiency, and well-being.
• A nutrient is essential for an organism's life and growth.
• Nutrients enable animals to carry out life processes and are provided through feed and water.
• Farm animals get nutrients from plants, plant products & by-products, and animal products.
• There are six essential nutrients for animals: water, carbohydrates, fats, proteins, minerals, and vitamins.

Water

• Water essential for animal life.
• Animals can survive longer without food than without water.
• Water is the largest component of living things, accounting for 50-75% of an animal's body weight.
• Water transports nutrients, aids digestion, removes wastes, maintains body temperature, and is required for milk production.

Carbohydrates

• Carbohydrates (C6H12O6 - Glucose) are energy-producing nutrients.
• Carbohydrates should comprise at least 75% of an animal's diet.
• Animals need energy for metabolic activity, physical work, and producing meat, eggs, and milk.
• Types of carbohydrates include monosaccharides such as Glucose, Fructose and Galactose.
• Other types of carbohydrates include Disaccharides such as Maltose, Sucrose, Lactose and Polysaccharides such as Starch cellulose, hemi-cellulose, lignin.
• Sources of carbohydrates are pasture grasses, plant products, and plant by-products such as root crops, fruits, seeds, grains, rice bran, wheat bran.
• Energy deficiency, including lack of carbohydrates, is the most common nutritional deficiency in grazing animals.
• Inadequate feed results from overgrazing, drought, poor quality/digestibility, or cost and forage may have excess water which limits energy intake.
• Energy deficiencies lead to retarded growth, delayed puberty, shortened lactation, milk production decline, marked weight loss, prolonged anestrus, and weak/undersized offspring.

Proteins

• Proteins are organic compounds comprised of amino acids with carbon, hydrogen, oxygen, and nitrogen.
• Proteins are needed for building new cells/tissues, producing milk/wool/hair/feathers, body maintenance/repair, and producing enzymes/hormones.
• Plant sources of protein include pasture legumes, field peas, and soybean.
• Animal sources of protein includes fish meal, bone meal, milk, meat meal, and blood meal.
• Protein deficiency usually goes hand in hand with energy deficiencies.
• Reduced appetite, lowered feed intake, lack of muscle development, prolonged time to maturity, weight loss, and decreased milk production are outcomes of Protein Deficiency.

Fats & Lipids

• Fats and lipids are composed of fatty acids and glycerol, and contain carbon, hydrogen, and oxygen.
• Fats contain 2.25 times more energy compared to carbohydrates.
• Fats are used to supply and store energy.
• Excess energy from carbohydrates is stored as fat which is stored under the skin, without the muscle tissues and in the abdominal cavity.
• Sources of fats include oilseed meals (copra, canola, linseed), vegetable oils, tallow, and lard.

Vitamins

• Vitamins are organic compounds needed in small amounts for healthy growth and development.
• Vitamins are divided into fat-soluble (A, D, E, K) and water-soluble (B and C) groups.
• The roles of vitamins in the diet include usage of protein, fats and carbs, blood clotting, bone formation, reproduction, lactation, and also preventing nervous disorders.
• Vitamin deficiencies can cause retarded growth, poor reproduction, skin ailments, hemorrhaging, diarrhea, night blindness, rough coat, and muscular problems.
• Sources of vitamins include green pasture grasses, legumes, legume hays, silage, cereal grains, oil seeds, sunlight, and injectable/packet vitamins.

Minerals

• Minerals promote healthy growth and development.
• There are 16 essential minerals, divided into macro and micro minerals with specific roles.
• Calcium and phosphorus are important for strong teeth and bones.
• Minerals help produce strong egg shells and prevent milk fever in dairy cattle.
• Mineral sources include green pasture grasses/forages, legumes, cereal grains, mineral licks, fish meal, bone meal, and shrimp meal.

Composition of the Animal Body

• J.B. Lawes and J.H. Gilbert analyzed farm animal bodies and published their findings in 1859.
• The levels of water and fat vary inversely.
• The composition of fat-free body is Water: Protein: Ash = 19:5:1 (74-76%:20-22%:3-5%).
• The composition of fat and moisture-free body is Protein: Ash = 80:20.
• The body composition of a moisture-free and fat-free body is practically constant.
• Water content decreases with age, for example:
  • A cattle embryo contains ~ 95% water.
  • A newborn calf contains ~ 75-80% water.
  • A 5-month-old calf contains ~ 66-72% water.
  • A mature animal contains ~ 50-70% water.
• Water distribution is not uniform.
  • Blood plasma contains 90-92% water.
  • Heart, Kidneys and Lungs contains 80% water.
  • Muscles contains 75% water.
  • Bones contains 45% water.
  • Teeth enamel contains 5% water.
• Water content in an animal’s body depends on its nutritional status.
• Protein along with inorganic elements are responsible for an animal's body structure.
• Protein is a major constituent of dry matter in muscles and other body organs and Muscles contain almost 75-80% protein.
• Protein is also present in hair, nails, feathers, hooves, skin, wool, tendons, and bones.
• Fat content increases with age and is the most variable body component.
• Fat is found in adipose tissues, under the skin, around the kidney, intestines, and other body organs.
• Only about 1% of the total animal body is composed of carbohydrates.
• Carbohydrates are constantly formed and broken down and usually present as glucose or glycogen in the muscles and liver.
• Calcium and Phosphorus are the minerals in largest amounts in the body and it is present in teeth and bones.
• Ca and P represent 70% of body ash and are the significant inorganic components of the body.
• Inorganic Elements such as Na, K, and Cl are present in inorganic form in fluids.
• Other minerals form components of tissues, fluids, and enzymes.