Chap 11-12

• Animal Health


  Refers to the physical and physiological well-being of animals, not only focused on infectious diseases, but also considers factors such as infectious causative agents, animal density, stress, boredom, nutrition, temperature, and shelter
• Animal Welfare


  According to OIE, it refers to how an animal is coping with the conditions in which it lives. An animal is in a good state of welfare if it is healthy, comfortable, well-nourished, safe, able to express innate behavior, and not suffering from unpleasant states like pain, fear, and distress
• Five Freedoms


  • Freedom from hunger and thirst
  • Freedom from discomfort
  • Freedom from pain, injury and diseases
  • Freedom to express normal behavior
  • Freedom from fear and distress
• Disease


  Defined as "lack of ease" or "discomfort", any deviation from normal health in which there are marked physiological, anatomical, or chemical changes in the animal's body
• Diseases can be regarded as infectious if they can be transmitted by direct or indirect contact and are caused by microorganisms
• Non-infectious Diseases


  Caused by factors other than living organisms, such as low-level nutrition, mechanical injuries and lesions, poisoning, hereditary conditions, and extreme conditions
• Causative Agents of Disease


  • Bacteria
  • Viruses
  • Protozoa
  • Parasites
  • Fungi
• Bacteria


  • Prokaryotic organisms, small and single-celled, can be cocci (round or oval), bacilli (rod-shaped), or spirilla (long cells twisted into spirals), also include rickettsia which can multiply only in living cells
• Viruses


  • Infective agents made up of nucleic acid (RNA or DNA) wrapped in a protein coat, no nucleus, organelles, cytoplasm, or cell membrane, able to multiply only within the living cells of a host
• Protozoa


  • Eukaryotic, single-celled organisms that come in many different shapes and sizes, some are parasitic and can move by cilia, flagella, or ameboid movement
• Parasites


  • Organisms that live in or on other organisms (hosts) and compete with them for nutrients, can be optional occasional, obligate occasional, determinate transitory, permanent, erratic, facultative, ectoparasites, or endoparasites
• Fungi


  • Eukaryotic, non-photosynthetic organisms that obtain nutrients through absorption, widely distributed in the environment and can produce spores, have two main morphological forms: molds (multicellular, branching filaments) and yeasts (unicellular, oval or spherical)
• Acute Diseases


  Start quickly and run a short course
• Chronic Diseases


  Run for an indefinite period
• Subacute


  A condition where clinical signs develop slowly
• Peracute


  Diseases that usually destroy the animals before clinical signs are seen
• Morbidity


  The number of animals in a herd or flock that are affected by the disease but do not die
• Mortality


  The number of animals dying from the disease
• Immunity


  The capability of an animal to resist harmful organisms, can be natural (without man's assistance) or artificial (with man's interference)
• Active Immunity


  When the animal produces antibodies within itself to combat the disease
• Passive Immunity


  When the animal receives antibodies from an outside source, provides immediate but temporary protection
• Disinfection


  The process of converting a place or object from a potentially infective state into one that is free from infection, involves cleaning as the first and most important stage
• Antiseptic


  Used for killing microbes on living tissues
• Disinfectant


  Applied on non-living objects to kill microbes
• Animal Hygiene


  Important means of preventing and controlling diseases, involves isolating infected animals and quarantining affected areas
• Treatment


  Increasing number of diseases can be successfully treated with modern drugs, requires caring for the treated animals in quiet surroundings with clean water, high quality feed, and soft bedding
• Exudative Epidermitis (Greasy Pig Disease)


  Caused by Staphylococcus hyicus, affects suckling piglets and weaned pigs up to 3 months, characterized by widespread excessive sebaceous secretion, exfoliation, and exudation of the skin, high morbidity (20-100%) and mortality (~90%), requires strict isolation and early antibiotic therapy
• Strangles


  Caused by Streptococcus equi, a highly contagious disease that usually affects young foals but horses of all ages are susceptible, clinical signs include high fever, depression, anorexia, and purulent oculo-nasal discharge, high morbidity (100%) but low mortality (5%), requires administration of penicillin and avoiding overcrowding and mixing of different age groups
• Caseous Lymphadenitis


  A chronic, suppurative condition in sheep, goats, and rarely cattle, caused by Corynebacterium pseudotuberculosis, results in abscessation and enlargement of lymph nodes with an onion ring appearance, animals become infected through contamination of shearing wounds or arthropod bites
• Streptococcus


  Gram positive bacteria in cocci chains
• Contagious disease affecting young foals

  • Usually affects young foals, although horses of all ages are susceptible
  • Clinical signs typically include high fever, depression, anorexia
  • Signs are then followed by purulent oculo-nasal discharge
• Treatment for contagious disease

  1. Administration of penicillin to in-contact and affected horses

  2. Overcrowding of horses as well as mixing them with different age groups should be avoided, as they are the predisposing factors to the diseases
• Caseous Lymphadenitis


  • Chronic, suppurative condition in sheep, goats, and rarely cattle
  • Caused by Corynebacterium pseudotuberculosis
  • Infection results in abscessation and enlargement of superficial or internal lymph nodes
  • Affected lymph nodes are enlarged and exhibit an onion ring appearance in the cross section
  • Become infected through contamination of shearing wounds or by arthropod bites
  • Chronic nature of the lesions and the ability of the organism to survive intracellularly, treatment is usually ineffective
  • Animals showing clinical signs must be culled
  • Disinfection must be performed at contaminated buildings and equipment
• Suppurative Bronchopneumonia


  • Caused by Rhodococcus equi, a Gram positive rod or cocci bacteria
  • Acquired by foals by inhaling contaminated dusts
  • Usually present in the feces of young foals up to 3 months of age
  • Clinical signs vary but acute signs (fever and anorexia) often occur in one month old foals
  • Foals 2 to 4 months of age usually exhibit coughing, dyspnea, weight loss, moist rales on auscultation
  • When grown on blood agar, they produce salmon-pink mucoid colonies
  • The recommended treatment is a combination of oral rifampin and erythromycin for 4 to 10 weeks
  • Regular removal of manure is recommended in the farm
• Bovine Actinomycosis (Lumpy Jaw)


  • Caused by Actinomyces bovis, a Gram positive bacteria
  • Presumed to invade the tissues following a trauma to the mucosa from rough food, or when a teeth is erupting
  • Mandible, and less commonly, the maxilla are targeted and exhibit rarefying osteomyelitis
  • When lesions are small, surgery is recommended
  • Prolonged treatment using penicillin can be of value to infected cattle
• Listeriosis


  • Caused by Listeria monocytogenes, a rod-shaped Gram positive bacteria
  • Tend to affect ruminants fed with infected silage
  • Can cause encephalitis, abortion, septicemia, and endophthalmitis
  • Listeria monocytogenes can replicate in poor quality silage with a pH of 5.5, exhibit tumbling motility at 25°C
  • Common clinical signs are dullness, circling, tilting of the head
  • Unilateral facial paralysis can result in drooping of ears and eyes
  • Abortion may occur without any evidence of systemic illness
  • Tx: Ampicillin or Amoxicillin
• Swine Erysipelas


  • Caused by Erysipelothrix rhusiopathiae, a Gram positive bacteria
  • Can be seen either as small rods (smooth form) or as filaments (rough form)
  • Acute infections produce smooth colonies, while chronic cases from rough one
  • Subclinically infected pigs are the main reservoir of the disease
  • It occurs in four forms: septicemic and cutaneous forms are acute, arthritis and vegetative endocarditis are the chronic forms
  • Septicemic form can occur 2-3 days after exposure, mortality may be high
  • Cutaneous form is characterized by diamond-shaped erythematous plaques
  • Chronic arthritis has the most significant negative impact on productivity
  • Vegetative endocarditis is less common, and most animals will appear asymptomatic
  • Chronically infected animals should be culled
  • Vaccines are available for the disease
  • Tx: Penicillin and Tetracycline
• Anthrax


  • Caused by Bacillus anthracis, a large, rod shaped, spore producing, and Gram positive bacteria
  • Severe disease that can affect all mammalian species, carnivores are relatively resistant while ruminants are highly susceptible
  • The endospores of B. anthracis can survive in the soil for decades, they can last longer in alkaline soils
  • In ruminants, the disease is septicemic and highly fatal, most animals can be seen dead without any early signs of the disease
  • Post-mortem findings include rapid bloating, incomplete rigor mortis, hemorrhage and edema, and dark unclotted blood
  • An extremely large spleen is also observed
  • Carcasses of suspected anthrax cases must not be opened as it will facilitate sporulation
  • Tx: High doses of Penicillin G and Oxytetracycline
  • Humans infected with anthrax can exhibit three forms: cutaneous, pulmonary, and intestinal
• Tetanus


  • Caused by Clostridium tetani, a large, rod shaped, spore producing, Gram positive bacteria
  • Is an acute, potentially fatal intoxication which affects many species, horses and man are highly susceptible, ruminants and pigs moderately, and carnivores are comparatively resistant
  • Clinical signs include stiffness, spasms, altered respiratory and heart rate, dysphagia, altered facial expression
  • Antitoxin should be given promptly, IV, for 3 consecutive days, toxoid may be given SC to promote an active immune response
  • Large doses of penicillin may be given IM to kill the bacteria
  • Surgical debridement of wounds or removal of foreign bodies, followed by flushing with hydrogen peroxide helps inhibit bacterial replication at the site
• Tuberculosis


  • Caused by Mycobacterium bovis, an acid-fast, rod shaped, bacteria
  • High lipid and mycolic acid content of their cell walls prevents uptake of the dyes used in Gram Staining
  • Clinical signs are only evident in advanced disease, development of coughing and intermittent pyrexia can be observed
  • Treatment is not recommended in cattle, test and slaughter policy is more ideal
  • Tuberculin test is the standard antemortem test in cattle, 0.1 ml of tuberculin is injected on the tail of cattle, a positive response will be a hard swelling in the tail