What is meant by the term feed additive?
any compound that is used in a ration that does not normally included in it and does not meet a dietary/nutritional need
What are the two main ways in which a feed additive functions?
- Enhance the effectiveness of nutrients 2. Improve handling and storage
What is the function of a preservative?
Protect the nutrients in the diet from damage
What are the three main ways antibiotics are used in animal production?
- Therapeutic use. - treating sick animals only 2. Prophylactic use - prevent infection 3. Growth promoting use - sub-therapeutic levels to improve production and to reduce the level of disease
How does sub-therapeutic antibiotic use improve prodcutivity?
What factors influence the level of succes of response to prophylatic antibiotics?
- Species- benefit is greatest in pigs and poultry
- Housing - most effective in intensive housing environments
- Age - greatest response in the youngest animals
- Diet - greatest response in plant based diets
- Herd health - greatest response in healthy herds/flocks
Why is antibiotic resistance an issue?
- Resistant bacteria have the potential to infect other animals/ humans
- Resistant genes can be passed on to other strains
What is an ionophore?
Coccidiostats (protozoan parasites) they are related to antibiotics (non-therapeutic antibiotics)
How do ionsphores increase production?
- increase propionate production
- decrease methane production
- decrease pasture bloat
- decrease acidosis
Why is it important to consider ionosphore toxicity?
- susceptibility and clinical signs will vary greatly between species
- horses are very susceptible (fatal cardiac arrythmias and weakness)
- salinomycin is safe for chickens but it is toxic for turkeys (results in muscle lesions in turkeys)
What is virginiamycin and what are it’s uses?
- antibiotic active against gram positive bacteria (used in pigs and chickens)
- also shown to decrease risk of rumen acidosis in sheep and cattle
- reduce risk of hindgut acidosis and laminitis in horses
What are some of the alternatives to using the virgineamycin as a drug?
- Slow introduction to high grain diets
- Roughage
- Grain amount (type and processing)
- Use buffers (e.g. bicarbonate)
What are some alternatives to antibiotics to antibiotics?
- Organic acids
- Minerals
- Probiotics
- Plant extracts
- Prebiotics
What is a repartitioning agent?
Repartitioning agents are compounds that affect body composition.
How do beta agonists work and what are the effects ot them?
beta agonists bind to adrenalin receptors and have strong effects on protein and fat metabolism. They increased carcass weight, reduced marble score and increased meat toughness.
How do hormonal growth promotants work?
- encouraged increased weight gains
- superior feed conversion (shorter time in feedlot, less feed inputs per kg of beef)
- leaner carcasses
- meat - facilitates toughening
