Unit 5: Feeding Management of Livestock

1. Digestion in Livestock and Poultry

Digestion is the mechanical, chemical, and enzymatic breakdown of feed into simpler substances that can be absorbed into the bloodstream. The digestive systems of livestock differ significantly based on their classification as ruminants or non-ruminants (monogastrics).

A. Ruminant Digestion (Cattle, Buffalo, Sheep, Goat)

Ruminants possess a complex, four-chambered stomach designed to ferment fibrous plant material.

1. Mouth:
   • Dental pad replaces upper incisors.
   • Saliva acts as a buffer (bicarbonate) to maintain rumen pH; no enzymes in saliva.
2. Stomach Compartments:
   • Rumen (Paunch): The largest fermentation vat containing billions of bacteria, protozoa, and fungi. Break down cellulose into Volatile Fatty Acids (VFAs - Acetate, Propionate, Butyrate), which provide energy. Synthesis of B-vitamins and microbial protein occurs here.
   • Reticulum (Honeycomb): Acts as a filter/trap for foreign objects (hardware disease). Facilitates regurgitation (cud-chewing).
   • Omasum (Manyplies): Absorbs water and VFA; reduces particle size.
   • Abomasum (True Stomach): Acidic environment (HCl) and enzymatic digestion (pepsin). Similar to the human stomach.
3. Rumination: The process of regurgitating, re-chewing, and re-swallowing feed to reduce particle size and increase surface area for microbial action.

B. Poultry Digestion (Monogastric/Avian)

Poultry have a simple stomach adapted for rapid digestion of concentrated feeds.

1. Beak & Mouth: No teeth; swallow feed whole. Saliva contains amylase.
2. Crop: A pouch in the esophagus for temporary storage and moistening of feed.
3. Proventriculus: The glandular (true) stomach. Secretes HCl and pepsin for chemical digestion.
4. Gizzard (Ventriculus): A muscular organ containing grit. Performs mechanical grinding of feed (acting as teeth).
5. Small Intestine: Major site of enzymatic digestion and nutrient absorption.
6. Ceca: Two blind pouches at the junction of the small and large intestine. Minor fermentation happens here.
7. Cloaca: Common exit for feces and urine (uric acid).

2. Classification of Feedstuffs

Feeds are broadly classified based on their fiber and moisture content.

A. Roughages

Feeds containing more than 18% Crude Fiber (CF) and less than 60% Total Digestible Nutrients (TDN). They are bulky and essential for rumen health.

1. Succulent Roughages (High Moisture: 60-90%):
   • Pastures/Grasses: Napier, Guinea, Para grass.
   • Legumes: Berseem, Lucerne (Alfalfa), Cowpea.
   • Tree Leaves: Subabul, Gliricidia.
   • Silage: Fermented green fodder preserved under anaerobic conditions.
2. Dry Roughages (Low Moisture: 10-15%):
   • Hay: Dried green fodder retaining nutrients.
   • Straws/Stovers: Paddy straw, Wheat straw (low nutritive value, high lignin).

B. Concentrates

Feeds containing less than 18% Crude Fiber (CF) and more than 60% TDN. They are energy or protein-dense.

1. Energy Rich Concentrates: <18% Crude Protein (CP). (e.g., Maize, Wheat, Sorghum, Barley, Molasses).
2. Protein Rich Concentrates: >18% Crude Protein (CP).
   • Plant origin: Soybean meal, Groundnut cake, Mustard cake.
   • Animal origin: Fish meal, Meat and bone meal.

3. Proximate Principles of Feed (Weende Analysis)

The system of analyzing feed into groups of substances with similar chemical properties.

4. Nutrients and Their Functions

A. Water

• Functions: Regulates body temperature, transports nutrients/waste, component of milk and eggs, lubricates joints.
• Deficiency: Dehydration, reduced intake, death.

B. Carbohydrates (CHO)

• Types: Soluble (starch/sugar) and Insoluble (fiber/cellulose).
• Functions: Primary source of energy for maintenance, growth, muscular activity, and heat production. Converted to fat if in excess.

C. Proteins (Amino Acids)

• Functions: Building blocks of body tissue (muscle, skin, hair), enzyme and hormone synthesis, antibody production, milk and egg production.
• Ruminants: Can utilize Non-Protein Nitrogen (NPN) like Urea to synthesize microbial protein.

D. Lipids (Fats)

• Functions: Concentrated energy source, carrier for fat-soluble vitamins (A, D, E, K), insulation, protection of vital organs. Essential fatty acids (Linoleic acid) are required for cell membrane structure.

E. Minerals

• Macro-minerals: Required in large amounts (Ca, P, Mg, Na, K, Cl, S).
  • Calcium & Phosphorus: Bone/teeth formation, eggshell formation, milk synthesis.
• Micro-minerals: Required in trace amounts (Fe, Cu, Zn, Mn, I, Co, Se).
  • Iron: Hemoglobin. Cobalt: Vitamin B12 synthesis (vital for ruminants).

F. Vitamins

• Fat-Soluble (A, D, E, K): Vision (A), Calcium absorption (D), Reproduction/Antioxidant (E), Blood clotting (K).
• Water-Soluble (B-Complex, C): Metabolic co-factors. Ruminants synthesize B-vitamins in the rumen; poultry must have them supplied in feed.

5. Feed Ingredients for Ration

A ration is the amount of feed allowed to an animal for 24 hours.

Energy Sources (Grains & By-products)

1. Maize (Corn): The standard energy source. Highly palatable, low fiber, high energy.
2. Sorghum (Jowar): Similar to maize but may contain tannins (anti-nutritional factor).
3. Wheat Bran / Rice Polish: By-products of milling. Good source of phosphorus and moderate energy.
4. Molasses: By-product of sugar industry. Improves palatability and acts as a binder; rapid energy source.

Protein Sources

1. Oil Seed Cakes: Residue after oil extraction.
   • Groundnut Cake (GNC): Highly palatable.
   • Soybean Meal (SBM): High protein quality (Lysine rich), standard for poultry.
2. Animal Proteins:
   • Fish Meal: Excellent source of high-quality protein and bypass protein; rich in calcium and phosphorus.
3. Non-Protein Nitrogen (NPN):
   • Urea: Can replace part of protein in ruminant diets. Toxic if not mixed well or fed to monogastrics.

6. Feed Supplements and Feed Additives

A. Feed Supplements

Nutritive substances added to fill specific nutrient gaps in the basal diet.

• Mineral Mixtures: Provide Ca, P, and trace minerals. (e.g., Dicalcium Phosphate, Limestone powder, Salt).
• Vitamin Premixes: Concentrated blends of Vitamins A, D3, E, and B-complex.
• Amino Acids: Synthetic Lysine or Methionine (common in poultry feed to balance protein).

B. Feed Additives

Non-nutritive substances added to improve feed efficiency, growth, health, or preservation.

1. Antibiotics: Growth promoters (low dose) to control sub-clinical infections.
2. Probiotics: Beneficial bacteria (Lactobacillus, Yeast) to improve gut health.
3. Prebiotics: Food for beneficial bacteria (e.g., MOS, FOS).
4. Enzymes: Phytase (to release phosphorus), Xylanase (to digest fiber in poultry).
5. Toxin Binders: Bind mycotoxins (fungal poisons) to prevent absorption.
6. Antioxidants: Prevent rancidity of fats in stored feed.
7. Coccidiostats: Prevent coccidiosis in poultry.

7. Feeding of Livestock and Poultry

A. Feeding Principles

• Balanced Ration: Must supply all nutrients in proper proportions and amounts.
• Palatability: Feed must be fresh and free from mold.
• Challenge Feeding (Dairy): Increasing concentrate feeding 2 weeks pre-calving to prepare the rumen for high production.

B. Feeding Categories for Cattle/Buffalo

1. Calf Feeding:
   • Colostrum: Must be fed within first 1-2 hours of birth. Provides antibodies (passive immunity) and acts as a laxative.
   • Milk Replacers: Cheaper alternative to whole milk.
   • Calf Starter: High-quality concentrate introduced at 2 weeks to stimulate rumen development.
2. Heifer Feeding: Focus on growth and skeletal development without excessive fattening.
3. Milking Animals:
   • Maintenance Ration: Keeps the animal alive without gain/loss of weight.
   • Production Ration: Additional feed based on milk yield (e.g., 1 kg concentrate for every 2.5–3 kg milk).
4. Dry Cows: Fed to regain body condition lost during lactation and support fetal growth.

C. Feeding Categories for Poultry

Poultry feeding is divided by phases to match rapid growth rates and production cycles.

1. Broilers (Meat birds):

• Pre-Starter (0-7 days): High Protein (~23%), easily digestible, crumbles.
• Starter (8-21 days): High Protein (~22%), high energy.
• Finisher (22 days - slaughter): Lower Protein (~19-20%), Highest Energy. Focus on weight gain.

2. Layers (Egg birds):

• Chick Mash (0-8 weeks): ~20% Protein.
• Grower Mash (9-18 weeks): ~16% Protein. Feed restriction may be used to prevent early maturity/obesity.
• Layer Mash (18 weeks+): ~16-18% Protein but High Calcium (3-4%) essential for eggshell formation.

3. Feed Forms:

• Mash: Ground feed (economical).
• Pellets: Compressed feed (reduces wastage, ensures balanced intake).
• Crumbles: Broken pellets (for chicks).