Animal Health and Disease Control
Recognising disease
Health is not merely the absence of disease; it is the animal's ability to function normally. Learn normal ranges - cattle rectal temperature about 38–39 °C, pulse 60–70 beats per minute, respiration 15–30 breaths per minute; poultry about 41 °C. A raised temperature, loss of appetite, dull coat, abnormal dung, lameness, discharges or a fall in milk yield all indicate a problem.
Classify diseases by cause: bacterial (anthrax, mastitis, foot rot), viral (foot-and-mouth disease, rabies, Newcastle disease), fungal (ringworm), parasitic (internal worms, ticks, coccidiosis) and nutritional or metabolic (bloat, milk fever, mineral deficiency). Know the tick-borne diseases of cattle - heartwater, anaplasmosis, babesiosis - and their control: dipping or spraying, vaccination, drenching, quarantine, isolation of sick animals, disinfection and vector control.
Traps to watch: confusing a zoonosis (transmitted to humans, e.g. anthrax, rabies, brucellosis) with a notifiable disease, although some are both; muddling the withdrawal period (the interval between the last dose and slaughter or milk sale); assuming antibiotics cure viral disease; and opening an anthrax carcass, which releases spores and permanently contaminates the ground - it must not be opened.
Worked example - withdrawal: a drug with a 7-day milk withdrawal period is given on 1 March; the milk may be sold from 8 March, counting from the day after treatment.