Antimicrobials: A generic name for both antibiotics and synthetic agents that have an antimicrobial effect. Most antibiotics are semi-synthetic, produced in large-scale microbial cultures, and then transformed by chemical processes.

Antibiotics: Natural substances produced by certain microorganisms which destroy or inhibit the growth of other microorganisms. Antibiotics are used to treat bacterial infections in humans and animals.

Cross-resistance: When a bacterium that acquires a resistance trait to one type of antibiotic also becomes resistant to another type of antibiotic.

Enterococcus: a bacterium commonly associated with bladder, skin and wound infections.

Escherichia coli: a bacterium commonly associated with a wide range of infections, including bladder infections and diarrhea.
Feed efficiency: The use of certain drugs which results in animals gaining more weight than animals not given such drugs for the same amount of feed consumed.

Growth Promotion Antibiotics / Digestive Enhancers: The use of certain compounds in low concentrations in feed (2.5 - 50 ppm) which results in animals growing faster than animals not given such drugs over the same time period and for the same amount of feed consumed. The mode of action is thought to be related to a suppression of commensal bacteria which would divert nutrition from the animal, and by maintaining a more effective and adsorptive gut lining. Some growth promoters appear to have an effect of suppressing disease. Generally they are used in poultry, swine, and beef cattle. In Canada some examples include Zinc Bacitracin, Chlortetracycline, Bambermycin, Lincomycin, Procaine Penicillin, Virginiamycin and Tylosin.

Judicious: sensible, prudent , sound in discernment and judgement.

Pathogen: A micro-organism capable of causing disease.

Prophylaxis / Preventative: Application of an antimicrobial to clinically healthy animals to prevent infection being either acquired or established after acquisition. Examples of application include prevention of mycoplasma in poultry, colibacillosis in post-weaning pigs, or shipping fever in feed lot cattle.

Probiotics: Beneficial micro-organisms which act to displace harmful micro-organisms in the gastrointestinal tract.

Prudent: (of a person or conduct) careful to avoid undesired consequences.

Salmonella: a bacterium most commonly associated with diarrhea and food poisoning.

Staphylococcus: a bacterium which cause a wide variety of infections especially of skin and wounds. More serious infections include blood poisoning and pneumonia as well as heart valve, bone and joint infections.

Sub-therapeutic: The use of drugs where the doses given are less than that which would be used if disease were present. In the context of the use of antibiotics in animals feeds, these uses include prophylaxis or prevention of disease and growth promotion or feed-efficiency effects of certain antimicrobials.

Therapeutic use: Application of an antimicrobial to combat an established infection. Mass oral medication, either via the feed or water, is frequently used in poultry and swine operations; larger food animals and companion animals are generally treated individually.

Zoonosis: an infectious disease of animals which can be transmitted to humans.