Topics covered:
Lesson 1: Hypothermia, Hyperthermia, Fever Lesson 2: Septicemia, Viremia Lesson 3: Toxemia and Endotoximea Lesson 4: Hypovolemic shock Lesson 5: Allergy and Anaphylaxis Lesson 6: Edema and acid-base imbalance Lesson 7: Pain and stress Lesson 8: Localized infections Lesson 9: Inappetence Lesson 10: Weight loss Lesson 11: Care of recumbent animals Lesson 12: Sudden and unexpected deathHypothermia: Body temperature below normal due to excessive heat loss or inadequate heat production.
Hyperthermia: Elevated body temperature due to failure of heat dissipation, not caused by a change in hypothalamic set point.
Fever: A regulated rise in body temperature resulting from pyrogenic mediators acting on the hypothalamic thermoregulatory center.
Hypothermia: Heat loss - heat production (neonates, anesthetized patients, environmental exposure).
Hyperthermia: Overheating (heat stroke, overexertion, confinement in hot conditions).
Fever: Release of cytokines (IL-1, IL-6, TNF-α) stimulates hypothalamus to reset body temperature higher.
Hypothermia: Shivering, weakness, bradycardia, reduced reflexes, eventual coma.
Hyperthermia: Panting, tachycardia, collapse, seizures, organ failure.
Fever: Anorexia, lethargy, increased HR, dehydration, malaise.
Rectal temperature measurement.
History (exposure, environment, illness).
CBC: leukocytosis (infection), dehydration markers.
Hypothermia: Gradual rewarming (warm IV fluids, blankets).
Hyperthermia: Active cooling (cool water, fans, IV fluids). Avoid ice water (causes vasoconstriction).
Fever: Treat underlying cause (antimicrobials, anti-inflammatories, fluids).
A newborn calf is found in a cold barn, unable to suckle and lying recumbent. Its rectal temperature is 34°C (normal approx 38.5°C). The calf is rewarmed with heat lamps, fed warm colostrum via tube, and gradually recovers.
Septicemia: The presence of bacteria and their toxins in the bloodstream, leading to systemic illness.
Viremia: The presence of viruses in the bloodstream, either transient (during infection spread) or persistent (chronic infections).
Septicemia: Entry of bacteria (umbilicus in neonates, mastitis, pneumonia) > toxins > systemic inflammation > shock.
Viremia: Viral replication in host > release into bloodstream > dissemination to target tissues.
Septicemia: Fever, tachycardia, injected mucous membranes, petechiae, depression, possible shock and death.
Viremia: Often asymptomatic early; may progress to systemic signs depending on virus (e.g., parvovirus causing enteritis, FMD causing vesicles).
Septicemia: Blood culture, CBC (leukocytosis/leukopenia).
Viremia: PCR, serology, virus isolation.
Septicemia: Broad-spectrum antibiotics, IV fluids, anti-endotoxin therapy.
Viremia: Supportive therapy (fluids, nutrition), antivirals where available (rare in livestock).
A 5-day-old foal develops lethargy, fever, and diarrhea. Blood culture reveals E. coli septicemia. The foal is treated with IV fluids, antibiotics, and plasma transfusion, but prognosis remains guarded.
Toxemia: Circulation of toxins (bacterial, fungal, chemical) in the bloodstream.
Endotoxemia: Specific form of toxemia caused by lipopolysaccharide (LPS) endotoxin from Gram-negative bacterial infections.
Toxins or endotoxins > widespread inflammation > cytokine release > vascular leakage, hypotension, organ dysfunction.
Endotoxemia commonly arises from Gram-negative mastitis, metritis, colic (horses), or GI diseases.
Fever, tachycardia, injected mucous membranes (“toxic line”), diarrhea, shock, sudden death.
Clinical signs plus history of bacterial infection.
CBC: leukopenia, toxic neutrophils.
Culture of source infection.
IV fluids and electrolytes to correct shock.
NSAIDs (flunixin meglumine) to block inflammatory cascade.
Polymyxin B (binds endotoxin, used cautiously).
Treat underlying infection (antibiotics, surgery if needed).
A high-producing dairy cow develops acute mastitis. Within hours, she becomes recumbent, with injected scleral vessels and cold extremities. Immediate aggressive IV fluids and flunixin are administered, but prognosis remains guarded.
Hypovolemic shock is a life-threatening condition resulting from significant fluid or blood loss, leading to inadequate tissue perfusion.
Loss of intravascular volume (hemorrhage, diarrhea, dehydration).
Reduced venous return > decreased cardiac output > poor oxygen delivery > cellular hypoxia > organ failure.
Tachycardia, weak or thready pulse.
Cold extremities, pale mucous membranes, prolonged capillary refill time (CRT).
Lethargy, collapse.
History of trauma, diarrhea, or blood loss.
PCV/TP to assess dehydration/hemorrhage.
Blood lactate (marker of perfusion).
Rapid IV fluid therapy (crystalloids, colloids).
Blood transfusion if hemorrhage.
Oxygen supplementation.
Address underlying cause.
A dog presents after being hit by a car with visible bleeding and pale mucous membranes. Shock is diagnosed and treated with IV fluids and a blood transfusion. The source of hemorrhage is surgically corrected.
Allergy: An exaggerated immune response to a normally harmless antigen.
Anaphylaxis: A severe, systemic allergic reaction that can be life-threatening.
Allergic reactions involve IgE antibodies triggering mast cell degranulation.
In anaphylaxis, widespread histamine release causes vasodilation, hypotension, and bronchoconstriction.
Mild allergy: itching, urticaria (hives), swelling.
Anaphylaxis: dyspnea, collapse, tachycardia, vomiting/diarrhea, death.
History of exposure (vaccine, drug, insect bite).
Rapid onset of signs.
Exclusion of other causes of collapse.
Anaphylaxis: Epinephrine IM or IV immediately.
Supportive: Oxygen, IV fluids, corticosteroids, antihistamines.
Allergy: Antihistamines, corticosteroids, avoidance of trigger.
A cow collapses within minutes of being given penicillin. Emergency epinephrine and IV fluids are administered, and the cow recovers after supportive care.
Edema: Abnormal accumulation of fluid in tissues.
Acid-base imbalance: Disturbances in blood pH due to respiratory or metabolic causes.
Edema: Caused by low plasma oncotic pressure (hypoproteinemia), increased hydrostatic pressure (heart failure), or lymphatic obstruction.
Acid-base:
Edema: Swelling in dependent regions, brisket, ventrum, eyelids.
Acid-base: Weakness, altered respiration, neurologic signs.
Edema: Physical exam, blood protein levels.
Acid-base: Arterial blood gas analysis, electrolyte testing.
Edema: Treat underlying cause, diuretics if needed.
Acid-base:
A cow with severe Johne’s disease presents with ventral edema due to hypoproteinemia. Supportive therapy is initiated, but prognosis is poor.
Pain and stress negatively affect animal health, productivity, and welfare. Recognizing and managing them is critical in veterinary practice.
Pain: Nociceptors transmit stimuli to CNS.
Stress: Activation of hypothalamic-pituitary-adrenal (HPA) axis > cortisol release > immunosuppression, metabolic effects.
Pain: Lameness, vocalization, reluctance to move, abnormal posture.
Stress: Restlessness, increased HR/RR, reduced productivity, suppressed immunity.
Pain scoring systems (lameness score, grimace scales).
Behavioral observation.
Pain: Analgesics (NSAIDs, opioids, local anesthetics).
Stress: Low-stress handling, adequate housing, minimize painful procedures.
A dairy cow post-dehorning is restless, shaking her head, and off feed. Administration of NSAIDs improves comfort and feed intake.
Localized infections are confined to one tissue or organ but may spread if untreated.
Bacteria invade locally > inflammation, pus formation.
May progress to systemic disease if barriers are breached.
Swelling, heat, redness, pain, discharge.
Loss of function of affected organ/tissue.
A sheep develops a swollen jaw due to caseous lymphadenitis. The abscess is drained, and the area is disinfected. Antibiotics are used where appropriate.
Inappetence is reduced appetite and is a nonspecific but important clinical sign.
Can be caused by systemic illness, pain, fever, or stress.
Linked to altered hypothalamic regulation of hunger.
Reduced feed intake, weight loss, depression.
Thorough history and clinical exam.
Lab tests: CBC, chemistry, fecal analysis.
Identify and treat underlying cause.
Nutritional support (tube feeding, IV glucose).
Appetite stimulants if necessary.
A cow with pneumonia refuses feed for 3 days. Antibiotic therapy resolves infection, and appetite returns.
Weight loss is a chronic sign of disease or inadequate nutrition.
Results from reduced intake, poor absorption, increased metabolic demand, or chronic disease.
Loss of body condition, poor growth, weakness.
History, body condition scoring.
Fecal exam (parasites), blood work (chronic disease).
Correct underlying disease.
Balanced nutrition, parasite control.
A goat loses weight despite good feed. Fecal exam reveals heavy parasite burden, and deworming leads to recovery.
Recumbency occurs when animals cannot rise, requiring intensive nursing care.
Causes: metabolic disease (hypocalcemia), trauma, neurologic disease.
Risk: muscle/nerve damage, pressure sores, pneumonia.
Animal unable to stand.
Secondary complications from prolonged recumbency.
Treat primary cause (IV calcium, surgery).
Supportive care: frequent repositioning, bedding, nutrition, hydration.
A dairy cow with milk fever is recumbent. She receives IV calcium and supportive nursing care. She rises within hours.
Death occurring without prior signs; requires thorough investigation.
Common causes: clostridial infections, acute poisoning, trauma, cardiovascular failure.
Often none before death; carcass may show bloating, hemorrhage, or lesions on necropsy.
Necropsy essential.
History (feed, environment, recent treatments).
Lab tests (toxicology, cultures).
Prevention via vaccination, good nutrition, and biosecurity.
A feedlot steer is found dead with no prior illness. Necropsy reveals clostridial enterotoxemia. Vaccination protocols are reviewed and updated.
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