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How do non-ionophore antibiotics work?
Produced by a living organism to inhibit the growth of another organism
reduce infections in the digestive and respiratory tract caused by bacteria
How do animal age, sanitation, and environment influence animal response to non-ionophore antibiotics?
A mature animal in a clean environment under good management practices will not see a large improvement from non-ionophore antibiotics because they are already healthy.
An animal in a stressful situation (such as traveling) may benefit from the antibiotics
Are the publics concern about non-ionophore antibiotics justified?
Antibiotic residue in food-residues are highly regulated, and there is little to no chance of there being any residue in livestock that consume these antibiotics.
Antibiotic resistance- there is little evidence that points to antibiotic use in livestock production as the cause of the antibiotic resistance. It is most likely a cause of improper use of antibiotics by humans.
How do ionophore bacteria work?
synthetic compounds that destroy gam positive bacteria in the rumen.
- Reduction of gram positive bacteria results in:
- *improved efficiency of nitrogen utilization
- * greater propionate production (increases efficiency)
- *reduced methane production
what is a chemotherapeutic agent?
synthetic organic or inorganic compound that inhibits the growth of pathogenic or parasitic organisms
What are coccidostats?
used to prevent and treat coccidiosis
what is an antihelmenthic?
What are probiotics?
organisms produced from specific microbial cultures that flourish in the GIT and compete with harmful organisms
naturally produced in the gut
little evidence to justify economically
What are antioxidants used for in feed?
They are compounds that prevent rancidity
Usually mixed with high fat ingredients
Why do we use chemical preservatives?
used to prevent product deterioration
- ascorbic acid
- citric acid
- porpionic acid
What is melengesterol acetate (MGA) and what is it used for?
- fed to feed lot heifers to suppress estrous
- similar to progesterone
- prevents heifers from expressing estrous
- prevents undesirable behavior
What are beta-agonists and what are they used for?
Orally active compounds that repartition nutrients towards lean muscle deposition and away from fat deposition
significantly increase red meat production
Only effective for a small period of time. Generally used for a short period at the end of the late finishing stage.
Why does the U.S government regulate feed additives in animal diets?
to ensure the safety of human foods
production animals are consumed by animals and indirectly we consume what they consume
What agencies regulate feed-additive use in animal diets?
- Food and Drug Adm. (FDA)
- US Department of Agriculture (USDA)
- Environmental Protection Agency (EPA)
- Various state regulatory agencies
American Association of Feed Control Officials (AAFCO) - responsible for establishing standards for 'good manufacturing practices' and labeling of livestock feed and pet food
What are the 7 elements that must appear on a feed label?
- 1. quantity
- 2. production name and purpose
- 3. guaranteed nutrient analysis
- 4. Ingredient composition
- 5. Directions for use
- 6. precautionary statement
- 7. name and address of manufacturer
Define type A medicated feed?
premixes manufactured medicated type B feed
Define type-B medicated feed?
premixes used to manufacture medicated type C-feed
Define type-C medicated feed
intended to be fed without further mixing
What additional labeling information is required for medicated feed?
The word 'medicated' must immediately follow the product name
purpose of medication - label claim
AAFCO - accepted name of each drug component
When applicable, withdrawl statements, cautionary statements, and warning statements
Explain category I of feed-additive drugs
Low risk of tissue residues
no pre-harvest withdrawal period is required
Explain category II of feed-additive drugs
preharvest withdrawal is required or there is a zero tolerance policy for residues.
why are animal diets processed?
- animal performance
- mixing characteristics
- feed handling and storage
simplifies bunk, or feed management
What are the strengths of a hammer mill?
- easily produces a wide range of particle sizes
- accommodates a wider variety of ingredients
- not as expensive as a roller mill
- easier to operate
what are the disadvantages of a hammer mill?
- less energy efficient than roller mills
- generates a lot of heat, dust, and noise
- less uniform particle size
what are the advantages of a roller mill as compared to a hammer mill?
- more energy efficient
- greater particle size uniformity
- generates less heat, dust, and noise
what are the disadvantages of a roller mill as compared to a hammer mill?
- poor performance with fibrous material
- more expensive
How is particle size significant in feed manufacturing?
Smaller particles can increase nutrient digestion
Smaller particles are more maintenance intensive to handle and manufacture
what is angle of repose?
a measure of how steeply a feed can be piled before it naturally collapses
What factors affect angle of repose?
- particle size
- fat content
- ground in hammer or roller (hammer more likely to cause bridging)
What are the benefits of a horizontal paddle mixer?
- Can handle variety of blends, including liquid
- capable of handling smaller batches then some mixers (as low as 10% capacity)
- easiest to clean
- least likely to have 'dead spots'
- minimal heating from friction
What are the disadvantages of horizontal paddle mixers?
longer mixing time
What are the benefits of a horizontal ribbon mixer?
- lower mixing time then paddle mixers
- clean up is relatively easy
- good for turning out a feed with few ingredients in large batches
What are the disadvantages of horizontal ribbon mixers?
- Must be filled to 70% capacity to work properly
- substantial heating from friction
- Ribbons must be constantly inspected for wear
What are the benefits of a rotating drum mixer?
- good for mixing the same diet all the time
what are the disadvantages of a rotating drum mixer?
- less efficient then other horizontal mixers
- does not work well with liquid ingredients or coarse material
- clean out is difficutl
what are the benefits of verticle mixers?
- suitable for small operations
what are the disadvantages of a vertical mixers?
- less efficient then horizontal mixers
- do not work well with liquid or fibrous ingredients
- clean out is difficult
what are the advantages of an auger mixer?
- used exclusively in ruminant diets
- handles forages and roughages
- horizontal sometimes have grinding capabilities
What are the disadvantages of auger mixers?
How is mixer efficiency measured?
Add a known amount of salt(NaCl) and measure the salt levels at different points all around the batch. There is generally an allowance of about 10% variation
Salt is its own ingredient and isn't found in any other feed ingredients so we can measure salt exclusively and compare for even mixing.
How do feed manufacturers prevent feed residue contamination?
- Pay attention to sequence of ingredients
- Pay attention to sequence of diets
- Be aware that electrostatic charges can cause ingredients to adhere to the sided and equipment
- Flush mixer with ground corn
What is the general order in which feeds should be added to a mixer?
- 1. Half the grain
- 2. Protein source
- 3. premixes and medications
- 4. Half the grain
How do heat, moisture and pressure affect the structure and digestibility of starch?
- disrupts protein granules surrounding starch granules
- gelatinizes starch granules
- increases ruminal starch fermentation, which in turn increases feed efficiency, growth and milk production
How does a steam flaker work?
Steam the grain and then smoosh it between 2 rolls
- Used primarily for ruminant feed
- Increases energy value of grains
- Increases ruminal digestion of starch
- Increases ruminal protein availability
How does a pellet mill work?
ground feed are forced through a die after undergoing steam and pressure
How does pelleting influence diet characteristics?
increases ADG and F:G in monogastrics
How do extruders work?
- Material forced through cylinder w/ auger
- Packed into prgresssively smaller space ^ heat and friction
- Heat, pressure, and shear alter ingredient structure
- Forced through small die at end of cylinder
- Expansion occurs due to sudden change in pressure.
How does expansion work?
Similar to extrusion, but pressure is controlled with plunger at the end of the expander barrel
How doe extruders an expanders influence diet characteristics?
produces higher quality pellets then unexpanded