Livestock Diseases by Etiology
Bacterial Diseases
1. Core systemic/zoonotic diseases
2. Clostridial diseases
3. Gastrointestinal diseases
4. Respiratory diseases
5. Reproductive diseases
6. Skin and soft tissue diseases
7. Production diseases (high economic impact)
Viral Diseases
1. Epitheliotropic / Vesicular Diseases
2. Neurological Viral Diseases
3. Respiratory Viral Diseases
4. Systemic / Generalized Viral Diseases
5. Enteric Viral Diseases
6. Reproductive Viral Diseases
7. Avian Viral Diseases
Diseases Associated with Rickettsiales
1. Anaplasmosis →
- Anaplasma marginale (bovine anaplasmosis)
- Anaplasma centrale (milder form in cattle)
- Anaplasma phagocytophilum (tick-borne fever in ruminants, granulocytic anaplasmosis)
2. Ehrlichiosis →
- Ehrlichia canis (canine monocytic ehrlichiosis)
- Ehrlichia ruminantium (heartwater in ruminants)
- Ehrlichia ewingii (granulocytic ehrlichiosis in dogs)
3. Rickettsiosis →
- Rickettsia rickettsii (Rocky Mountain spotted fever)
- Rickettsia conorii (Mediterranean spotted fever)
- Rickettsia africae (African tick bite fever)
4. Neorickettsiosis →
- Neorickettsia risticii (Potomac horse fever)
- Neorickettsia helminthoeca (salmon poisoning disease in dogs)
5. Q Fever →
- Coxiella burnetii (important zoonotic reproductive disease in ruminants)
Other Related/Important Infections
Fungal Diseases (Mycoses)
Diseases Associated with Helminth Parasites
Diseases Associated with Arthropod Parasites
Metabolic Diseases →
- Ketosis (dairy cows, negative energy balance)
- Milk Fever (hypocalcemia, parturient paresis)
- Pregnancy Toxemia (ewes, does)
- Hypomagnesemic Tetany (grass tetany)
- Acidosis (ruminal acidosis)
- Urolithiasis (urinary stones in ruminants)
- Laminitis (linked to carbohydrate overload in horses/cattle)
Nutritional Deficiency Diseases →
- Rickets (calcium, phosphorus, or vitamin D deficiency)
- Osteomalacia (adults, similar to rickets)
- White Muscle Disease (selenium/vitamin E deficiency)
- Grass Tetany (magnesium deficiency)
- Anemia (iron deficiency, especially piglets)
- Pica (phosphorus deficiency)
- Goiter (iodine deficiency)
- Night blindness (vitamin A deficiency)
Diseases Caused by Physical Agents
Trauma & Mechanical Injuries →
Including Fractures, Wounds, Dislocations, Hematomas and Contusions.
Heat-Related Disorders →
Including heat stroke, heat exhaustion, burns and photosensitization.
Cold-Related Disorders →
Including frostbite, hypothermia, chilblains
Radiation-Related Conditions →
Sunburn (Solar dermatitis), Skin cancer, radiation burns
Pressure & Confinement Injuries →
Including Decubital Ulcers (Pressure Sores), Sole Ulcers / Laminitis, Myopathy (“Downer Cow Syndrome”).
Electrical & Lightning Injuries →
Electrocution and Lightning Strike Injuries
Drowning & Suffocation →
Drowning, Smothering and Aspiration Pneumonia
Other Physical Agents
Allergic Reactions in Animals →
- Equine Recurrent Airway Obstruction (RAO/Heaves) – dust, moldy hay allergens
- Atopic Dermatitis – dogs and cats (skin allergy due to pollen, dust mites, food allergens)
- Flea Allergy Dermatitis (FAD) – hypersensitivity to flea saliva (dogs, cats)
- Sweet Itch (Insect Bite Hypersensitivity) – horses (reaction to Culicoides bites)
- Milk Allergy in Calves – hypersensitivity to milk proteins
Genetic Diseases in Animals →
- Albinism – absence of pigmentation (all domestic species)
- Chondrodysplasia (dwarfism forms) – dogs, cattle, sheep
- Hydrocephalus – multiple species
- Cryptorchidism (retained testes) – horses, dogs, cats, pigs
- Polydactyly (extra digits) – cats, chickens, cattle
Genetic Diseases in Cattle →
- Bovine Leukocyte Adhesion Deficiency (BLAD) – Holstein cattle
- Complex Vertebral Malformation (CVM) – Holstein cattle
- Bovine Progressive Degenerative Myeloencephalopathy ("Weaver syndrome") – Brown Swiss cattle
- Deficiency of Uridine Monophosphate Synthase (DUMPS) – Holsteins
- Factor XI Deficiency – Holsteins, Japanese Black cattle
- Arachnomelia (spider calf syndrome) – Brown Swiss, Holstein
Genetic Diseases in Horses →
- Hyperkalemic Periodic Paralysis (HYPP) – Quarter Horses, American Paint Horses
- Polysaccharide Storage Myopathy (PSSM) – Quarter Horses, Warmbloods, draft breeds
- Severe Combined Immunodeficiency (SCID) – Arabian horses
- Hereditary Equine Regional Dermal Asthenia (HERDA) – Quarter Horses
- Cerebellar Abiotrophy (CA) – Arabians
- Lethal White Foal Syndrome (Overo lethal white, OLWS) – American Paint Horses
Genetic Diseases in Dogs →
- Hip Dysplasia – large breeds (German Shepherds, Labradors, Rottweilers)
- Progressive Retinal Atrophy (PRA) – many breeds (Collies, Irish Setters)
- Collie Eye Anomaly (CEA) – Collies, Shetland Sheepdogs
- Degenerative Myelopathy – German Shepherds, Corgis
- Von Willebrand’s Disease – Dobermans, Shetland Sheepdogs
- Muscular Dystrophy – Golden Retrievers
- Cystinuria – Newfoundlands, Bulldogs
Genetic Diseases in Cats →
- Polycystic Kidney Disease (PKD) – Persian cats and related breeds
- Hypertrophic Cardiomyopathy (HCM) – Maine Coon, Ragdoll
- Progressive Retinal Atrophy (PRA) – Abyssinians, Siamese
- Hemophilia B – British Shorthair
- Spinal Muscular Atrophy (SMA) – Maine Coon cats
Genetic Diseases in Sheep and Goats →
- Spider Lamb Syndrome (Hereditary Chondrodysplasia) – Suffolk and Hampshire sheep
- Hereditary Splayleg – sheep and goats
- Goat Myotonia Congenita ("Fainting goats") – Tennessee fainting goats
- Entropion (inward eyelids) – hereditary in some sheep breeds
Genetic Diseases in Pigs →
- Porcine Stress Syndrome (PSS) – associated with malignant hyperthermia in Landrace, Pietrain
- Rectal/Anal Atresia – hereditary defect
- Congenital Tremors (type AII) – some pig lines
- Scrotal/Ventral Hernias – hereditary predisposition
Genetic Diseases in Poultry →
- Tibial Dyschondroplasia – broiler chickens, turkeys
- Crooked Toes – hereditary trait in some chicken lines
- Hypopigmentation ("Albinism") – rare genetic defect in poultry
Diseases of Complex or Unknown Etiology
- 1. Colic in Horses – dietary, management, stress, parasites →
- 2. Feline Idiopathic Cystitis (FIC) – stress, diet, genetics, environment →
- 3. Lameness in Dairy Cattle – housing, nutrition, infection, conformation →
- 4. Bovine Respiratory Disease Complex (BRDC) – viruses, bacteria, stress, environment →
- 5. Mastitis (certain chronic or recurrent forms) – pathogens, milking hygiene, cow immunity, environment →
- 6. Sudden Infant Piglet Death Syndrome (SIDS-like) – uncertain, multiple factors suspected →
- 7. Johne’s Disease – Mycobacterium avium subsp. paratuberculosis infection influenced by genetics, nutrition, environment →
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Take Home
Animal diseases can arise from a wide variety of causes, broadly classified into infectious agents such as bacteria, viruses, fungi, protozoa, helminths, arthropods, and prions, as well as non-infectious factors including nutritional deficiencies, metabolic imbalances, toxins, physical agents, and exposure to inorganic or farm chemicals. Infectious diseases often spread rapidly within populations, while parasitic infestations may cause chronic production losses. Nutritional and metabolic disorders usually reflect imbalances in diet or physiology, and toxic diseases result from exposure to poisonous plants, microbial toxins, chemicals, or heavy metals. Physical agents such as trauma, heat, cold, and radiation can also cause significant injury and disease. In addition, some conditions are genetic, allergic, or multifactorial in origin, influenced by complex interactions between the animal, environment, and management. Together, these categories highlight the diverse etiologies of animal diseases and the importance of a comprehensive veterinary approach to diagnosis, prevention, and control.