Implants Flashcards
methods of hormonal manipulation (7)
castration
age
implants
MGA
genetics
nutrition
health
where is castration an important hormone technique
brazil where implants are not approved for use
how is finished weight determined
body weight where a specific body fat content is reached
steroid hormones
derived from cholesterol
wide variety
estrogenic hormones
estrodiol
non steroidal estrogens
zeranol
androgenic hormones
testosterone
progestin hormones
progesterone
MGA (feed additive)
genomic or direct mechanism of action
effect DNA
regulate transcriptional processed via nuclear translocation
leads to enhanced translation and increased protein synthesis
indirect mechanism of action
binds a target gland resulting in a cascade of events that alter biological activity
IGF-1 indirect effects
IGF1 increase DNa increase protein synthesis increase hypertrophy (cell size)
TBA
trenbolone acetate
direct effect of TBA
increased protein synthesis
indirect effect of TBA
decreased protein catabolism
TBA structural similarity
testosterone and estrogen
what does TBA interphere with
corticotrophin induced stimulation of cortisol production
satillite cells in young and adult calves
high in young calves for hypertrophy
decrease as age require hormones to keep muscle cells
how does estrogen improve growth rate and feed efficiency
by how much
increase N retention
growth rate by 10-20%
FE by 5-8%
net effects of TBA
reduced cortisol
increased protein synthesis
increased IGF 1 levels
comination of estorgens and androgens
additive action
decr cort
incr protein synth
combined has more effieicnt response
been using hormonal implants since the
1950s
first generation implants had effective range
60-200 days
first generation implants FE and ADG
5-10% improve FE
5-15% improve ADG
WW increase in suckling calves with first gen implants
+20-40 lbs
dont use estrogen based implants for
heifer and steers >45d or bulls that will be used for breeding
too high implant dose
decrease efficiency
implants promoted
higher DMI
what are low potency implants used in
young calves
what are mod potency implants used in
stockers
not confined
what are high potency implants used in
feedlot
confined
when do you want the highest potency implant
last
last decade payout periods have been up to
200d
buller frequency
2.5% is typical
3-5% on agressive implant programs
how do you get stagy
TBA estrogen programs (re implanting)
can you implant heifers to use for breeding
take caution. could implant once if you really want to
step 1 implant strat
determine terminal implant
should be most potent
step 2 implant strat
determine days from arrival to terminal implant date
STR + TBA implant results
11.5% increase in intake
21.85 increase in weight gain
18.7% increase ADG
3.7% incrase gain to feed
