SWINE LABORATORY

Swine Laboratory: Anatomy and Physiology of Swine

Major Systems

  • Skeletal System

    • Supports the body, protects organs, enables movement.

    • Provides structural support while being strong yet flexible.

    • Bones serve to safeguard internal organs and store minerals like calcium.

    • Combines to form 200 bones, varying with age and breed.

    • Contains bone marrow which produces blood cells.

  • Muscular System

    • Facilitates movement, digestion, and heart function.

    • Smooth Muscle:

      • Found in walls of internal organs and blood vessels.

      • Involuntary muscle controlling internal system movements (e.g., stomach, intestines).

    • Cardiac Muscle:

      • Exclusive to the heart, involuntary with intercalated discs for synchronized contraction.

      • Essential for pumping blood.

    • Skeletal Muscle:

      • Voluntary muscles attached to bones enabling movement (e.g., hamstring, shoulder).

  • Digestive System

    • Classified as monogastric (1 stomach).

    • Mouth: Starts chemical breakdown of food with saliva; crushes food to increase surface area.

    • Stomach:

      • Stores food and breaks down nutrients through 4 sections: esophageal, cardiac, fundic, pyloric.

    • Small Intestine: Major nutrient absorption site divided into three parts: duodenum, jejunum, ileum.

    • Large Intestine: Absorbs water and ferments fiber using microorganisms, producing volatile fatty acids which serve as energy sources.

  • Circulatory System

    • Closed loop of blood vessels and heart circulating blood throughout the body.

    • Size is approximately that of a fist; main role is to deliver oxygen and nutrients while removing waste.

    • Structure:

      • Comprised of heart chambers (left/right atrium, left/right ventricle) and valves for unidirectional blood flow:

        • Tricuspid Valve: Between right atrium and right ventricle.

        • Pulmonary Valve: Between right ventricle and pulmonary artery.

        • Mitral Valve: Between left atrium and left ventricle.

        • Aortic Valve: Between left ventricle and aorta.

    • Blood Flow Sequence:

      • Right atrium receives deoxygenated blood from the body (via superior & inferior vena cava).

      • Blood moves to right ventricle, pumped through pulmonary valve to lungs.

      • Oxygenated blood returns to left atrium via pulmonary veins and is pumped into aorta.

Respiratory System

  • Responsible for oxygen intake and carbon dioxide removal, crucial for cellular respiration.

  • Structure:

    • Nose & Nasal Cavity: Filters, warms, and moistens air; traps particles/pathogens via cilia/mucus.

    • Pharynx: Connects nasal cavity to larynx.

    • Larynx: Contains vocal cords and directs air to trachea.

    • Trachea: Conducts air to lungs.

    • Bronchi/Bronchioles: Branches from trachea into each lung.

    • Lungs: Major site for gas exchange.

    • Alveoli: Tiny air sacs for gas exchange.

    • Diaphragm: Primary muscle involved in breathing.

  • Breathing Process:

    • Inhalation: Air enters via nasal cavity, filtered/warmed; moves through pharynx, larynx, trachea to lungs.

    • Gas Exchange: Oxygen enters bloodstream via alveoli; carbon dioxide is expelled.

    • Exhalation: Air exits lungs through alveoli, bronchi, and trachea to nasal/oral cavity.

Nervous System

  • A complex network regulating bodily functions and facilitating communication and responses to stimuli.

  • Components: Brain, spinal cord, peripheral, and central nervous systems.

  • Common Diseases:

    • Aujeszky’s Disease: Caused by pseudorabies virus; affects young pigs.

    • Porcine Teschovirus (PTV): Leads to high morbidity/mortality in young pigs.

    • Porcine Astrovirus 3 (PoAstV3): Causes CNS disease with symptoms like incoordination and tremors.

Reproductive System

  • Facilitates efficient mating, fertilization, and offspring development.

  • Components:

    • Boar: Testes, epididymis, vas deferens, accessory sex glands, penis.

    • Sow: Ovaries, oviducts, uterine horns, cervix, vagina, vulva.

  • Estrous Cycle: Regular physiological changes in females regulating reproduction.

    • Stages include Proestrus, Estrus, Metestrus, and Diestrus.

Selection and Culling for Foundation Stocks

  • Factors to Consider in Breeding Stock Selection: Availability, market demand, experience, personal preferences, feed availability, disease resistance, reproductive performance, carcass quality.

  • Selection Methodologies:

    • Individual selection, pedigree selection, family selection, etc.

    • Culling addressed through reproductive failures, maternal instincts, and health indicators.

Summary of Judging and Scoring Pigs

  • Judging: Evaluating pigs against specific standards.

  • Scoring: Determining overall quality for breeding, production, or showing.

    • Key Factors for Judging Market Swine: Conformation, balance, muscle quality, size/scale, structure.

    • Estimation of Live Weight Formula: SI = 240 + [(100)(ADG)] - [(50)(FCR)] - [(19.7)(BF)]