Feed Additives Flashcards
feed additives are
non nutritive substances that you can add to feeds in small quantities to meet goals
goals of feed additives (6)
improve feed efficiency
stimulate production
increase feed acceptance
enhance feed safety
improve animal health
reduce GHG
compendium of medicating ingreidient brochures
specifies species, level of mediation, directions for feeding, and purpose for medicinal ingredients
what groups of animals to antibiotics have the most impact on
young unthrifty or stressed
subtherapudic antibiotic levels were used to
promote growth and improve feed conversion
mode of action of antibiotics in growth (5)
supress mild or unrecognizable infections
reduce growth depressing toxins
reduce microbes destroying nutrients in gut
enhance efficiency of nutrient absorption
channel nutrients away form immune system towards growth
health canada antibiotic use restriction
restricts antibiotic usage in food animals to treatinf specific disease under vet direction
why are in feed antibiotics used
mostly to control liver abscess
liver abscess prevalance in cattle
12-32 % with increase over time
liver abscess impact on ADG and FE
11% reduction in ADG
9.7% reduction in FE
liver scoring system 3 levels
0
A 1 or 2 small abscesses
A+ most severe damage
most common liver abscess bacteria
fusobacterium necrophorum
tylosin dose rate
11ppm
what bacteria does tylosin work against
gram positive mostly
some negative
mechanism of tylosin
inhibits bacteria protein synthesis
tylosin impact over time
trend is decreasing effectivity
how does virginiamycin work
limits rumen lactic acid production minimizing SARA risks
ionophore prescriptions requirement
not needed as doesnt impact human amr
what bacteria do ionophores work on
gram positive
how do ionophores work
improve feed conversion by increasing production of propionic acid
what do ionophores prevent (3)
ketosis, lactic acidosis, bloat
ionophore mechanism of action
attaches to cell membrane of bacteria and protozoa in the rumen
solubilized in lipid bilayer
cation is exchanged for a proton
disrupts ionic gradient resulting in decreased intracellular pH
how do gram negative bacteria resistant ioniphores
outer cell membrane
what results for shift from gram pos to gram neg bacteria
less acetate and butyrate
methane and propionate
more propionate results in less methane production and therefore more efficient energy usage
monensin feeding dose to improve feed efficiency
33-48 mg/kg
relation between monensin response and fat content in diet
higher fat content results in less response
how do ionophore impact ruminal pH
promote higher and more stable pH
more stable eating patterns
how does ionophores reduce bloat
decreased viscosity of rumen fluid
lasalocid (bovatec)
improvement in feed efficiency and ADG
no impact on DMI
prevention of coccidiosis for calves up to 350kg
lasalocid (bovatec) dose
36 ppm
salinomycin sodium (posistac)
improvement in feed efficiency in growing/finishing cattle only
salinomycin sodium (posistac) dose
100 mg/hd/d
B-Adrenergic ligands
act on B-adrenergic receptors to cause a shift in carcass composition from fat to muscle
increased lipolysis
increase muscle hypertrophy
increase carcass leanness
increase skeletal muscle mass
how does ractopamine increase protein synthesis
increasing myofibrillar protein mRNA and protein production
can you feed ractopamine to animals that will be kept for breeding
no
when would you feed ractopamine to a feedlot cattle
> 400kg
last 28-42 d prior to slaughter
ractopamine improvement in carcass weight
7-20 lb
greater response in steers than heifers
Lubabegron (experior)
antagonistic activity for B1 and B2 AR
reduce ammonia gas emissions and urea excreted in manure
experior dose and timing
1.5-5.5 mg/kg DM
last 14-91 days on feed
DMI ADG and G:F for experior
incr DMI by 0-2.3%
incr ADG by 12%
incr G:F by 10%
Bovaer
inhibits CH4 production by 30%
more in higher concentrate diets
by increasing propionate and hydrogen gas production
Bovaer feeding and dose
60-200 mg/kg DM
must be fed daily
how do enzymes increase ruminal digestion
direst hydrolytic effect- act on fiber feeding
synergistic effects on rumen microbes- increase attachment to feed and microbial numbers
issues with enzymes
inconsistent responses
not formulated for optimal activity
need for further development
probiotics are
direct fed live microbes
probiotics potential modes of action
improve GI microbial balance
synthesis of lactic acid
adhesion to intestinal mucosa
stimulation of immune response in the gut
potential benefits of probiotics
increased feed intake
improved fiber digestion
increased N retention and muscle gain
what are prebiotics
induce the growth or activity of beneficial microorganisms
what are essential oils
naturally occurring volatile components responsible for giving plants and spiced their characteristic essence and colour
what properties do essential oils have
antimicrobial properies
essential oils effect on ruminal N metabolism
reduced deamination of AA and production of ammonia
only in HIGH DOSES which risk inhibiting fermentation
essential oil benefits over time
reduced effectiveness
2 types of tannins
hydrosable: easily hydrolyzed by heating with weak acid
condensed: can precipitate proteins and form soluble and insoluble complexes with various molecules
moderate levels of tannins
0.5-5.5% of DMI
increase diet protein availability in SI
improve growth performance
high inclusion of tannins
> 8% DMI
low palatability
reduce DMI and CP digestibility
fatal level of CT
> 9%
