exam 5: New material Flashcards
(151 cards)
various non-nutritive substances are
added to a ration to
- stimulate growth or other types of performance
- improvement of feed utilization or feed efficiency
- improving the health of the animal
general info on types of feed additives
-some have demonstrated situation-specific responses while others are universal
-Factors other than bio-efficacy considered relative to the use of an additive: cost, toxicity, tissue residues.
-In general, most feed additives produce their response in young, rapidly growing animals. There is seldom any benefit in mature animals (buffers and thyroprotein compounds being two exceptions).
what are the two exceptions of feed additives that are beneficial to mature animals
buffers and thyroprotein compounds
Most common use of nonnutritive additives are as:
antibacterial agents
hormones and their derivatives
others (buffers, antioxidants, enzymes etc)
what are the two main examples of antibacterial agents
antibiotics
sulfa drugs
examples of feed additive classifications
Medications
Antioxidant
Antifungal Agents
Enzymes
Herbs
Pellet Binders
Surfactants
Pigments
Direct‐Fed Microbials
Essential oils
Fermentation
Products
Flavors
Stool Conditioners
Buffers
feed additive: general modes of action
Sub-therapeutic antibiotics:
Decrease sub-clinical infection
decrease growth depressing microbial metabolites
decrease gut maintenance (turnover and inflammation)
decrease competition for nutrients
what do plant extracts do
–Varied physiological functions
–Antimicrobial
–Altered mucin production
–decrease intestinal “turnover”
what do probiotics do
–specific pathogen(s) exclusion
–Immunological modulation
–Improved nutrient use
–Antimicrobial action (pH ↓ &
bacteriocins)
antimicrobial agents and anthelmintics are defined as ________ by the Food and Drug Administration (FDA)
drugs
FDA regulates the ______________ of antimicrobial agents and anthelmintics
usage levels
allowable combinations
periods of withdrawal prior to slaughter
a compound synthesized by a living organism that inhibits the growth of
another organism.
antibiotic
It is well-recognized that antibiotics effective in
improving the performance of animals has one thing in common, ______________________________.
their ability to suppress or inhibit growth of certain microorganisms
how are antibiotics absorbed
readily absorbed into the vascular system of the host animal
others are hardly absorbed at all
Levels fed: general performance enhancement
low levels of 5-50 g/ton
Levels fed: disease prevention levels
50-200 g/ton feed
Levels fed: therapeutic levels
200-500 g/ton
Aimed at the control of respiratory diseases, and diarrhea
particularly useful for short-term treatment of the entire group of animals.
effects of antibiotic feeding
- Animals responding to antibiotic feeding consume more feed than controls, gain weight faster, and thus less feed is needed per unit of gain
- Reduced morbidity (sickness)
- Reduced mortality (death)
- Reduced incidence of secondary infections,
dehydration, pneumonia, etc.
effects of antibiotic feeding specific to feedlot cattle
best benefit to young, stressed calves arriving to feedlot
also cattle that have been mismanaged
feeding antibiotics reduces the incidence of liver abscesses of high grain rations for feedlot cattle
effects of antibiotic feeding specific to dairy cattle
does not increase milk production
high levels of antibiotics to lactating dairy cows are prohibited by law as there may be residue into the milk
Antibiotics are drugs, not nutrients, and thus their
effects upon the nutrition of animals must be _______
secondary
The mode of action of antibacterial drugs
appears complex and there are at least three plausible populations (assumptions):
what are the three assumptions
- Metabolic effect– drug affects various enzyme systems like phosphorylation
- Nutrient sparing effect– via altered microbial
composition of the G.I. tract - Disease control– benefits from suppression or control of subclinical or non-specific diseases
Nutrient sparing effect- via altered microbial
composition of the G.I. tract wherein the antibiotic
may:
a. stimulate microorganisms in the G.I. tract which
favor nutrient synthesis of a critical nutrient(s)
b. suppression of organisms that compete with
the host for dietary needs
c. improved nutrient absorption resulting from
thinner, healthier intestinal walls for antibiotic fed
animals.
what are some societal concerns regarding antibiotics
are they less effective?
does feeding them pose a public health threat?