Final Exam Review Notes

Last class meeting before final exam; consultation days are upcoming (no regular class scheduled).
Students encouraged to email for appointments on Thursday or Friday for assistance with exam preparation.

Morbidity: Refers to sickness or unhealthiness in a population. Example: Morbidity percentage of semen indicates how many sperm cells are non-viable (dead).
Mortality: Refers to the death rate within a population. Important for assessing risks in livestock.

Infectious Diseases: Capable of invading and growing in healthy tissue; they invade a host and reproduce. Can be confused with contagious diseases.
- Contagious Diseases: Transmitted from one host to another; requires exit from one host to infect another.
- Non-Contagious Diseases: Typically non-infectious; often nutritional deficiencies, like selenium deficiency.

Observations are crucial; animals may mimic eating behavior while actually not consuming food, especially prey animals.
Need to identify signs like:
- Depression: Animal appears lethargic, with drooping ears and lowered head position.
- Weakness: Difficulty moving; less active than usual.
- Gauntness: Notable weight loss; visible skeletal structures.
- Respiratory Issues: Difficulty breathing or coughing, which could indicate pneumonia or other respiratory diseases.

Acute Diseases: Rapid onset, can lead to severe illness or death overnight. Examples:
- Overeating disease (Enterotoxemia) in sheep (from clostridia bacteria).
- Milk fever in dairy cattle (calcium depletion post-calving).
Chronic Diseases: Develop over time; periods of flare-ups and decline. Examples:
- Asthma in humans is akin to chronic pneumonia in livestock; stress can trigger flare-ups in dormant infections.

Bacteria: Have a cell wall; vaccines and antibiotics can target their cell walls. Example: E. coli and its variants.
Viruses: Lack cell walls; challenging to create vaccines because of rapid mutation rates. Treatment is usually supportive therapy. Examples include the flu or common cold.
Protozoa: Single-celled organisms larger than bacteria. They require a living host and can survive in cyst form, making eradication difficult. Example: Coccidia in sheep.
Prions: Misfolded proteins that damage brain tissue leading to diseases like scrapie in sheep or chronic wasting disease in deer.

Importance of understanding normal animal behavior and feces characteristics to detect diseases early.
Common clinical signs:
- Nasal discharge (color can indicate type of infection: white for viral, yellow/green for bacterial)
- Changes in appetite (e.g., going off feed)
- Signs of dehydration (skin elasticity tests)

Diseases can be transmitted through:
- Fecal Matter: Ingestion of contaminated water or feed (E. coli, Campylobacter).
- Nasally: Airborne droplets from sneezing/coughing.
- Bloodborne: Via external or internal parasites.
- Importance of good management practices to mitigate disease spread, especially in high-density animal settings.

Recognition of dehydration in livestock by observing specific physical signs (like skin elasticity and gauntness).
Attention to young livestock is crucial; they are vulnerable to rapid decline from infections.
Regular check-ups for all livestock to identify clinical signs promptly and respond accordingly (e.g., providing fluids or antibiotics as needed).