Bovine - Female Pharmacology Flashcards
Note… see flip side
Dr. Dohlman said that he would give us the protocols so this flashcard set is the basics of estrus sychronization
What are the advantages of estrus synchronization?
reduce time and labor, efficiency use of ART (AI + ET), group breeding/calving, and decrease bull utilization
What are the disadvantages of estrus synchronization?
cost of drugs, use of drugs, group calving, reduced conception rates, and planning
What is the goal of estrus sychronization?
to synchronize the group to the same phase of the estrous cycle (timing)
What does FTAI stand for?
fixed time artificial insemination
What does FTET stand for?
fixed time embryo transfer
What are the four important factors for controlling the estrous cycle?
synchronizing emergence of new follicular wave, terminate luteal phase, maintain the luteal phase, or synchronizing ovulation
What is defined by the degree of synchronization?
The speed at which progesterone falls and the maturity of the dominant follicle at the progesterone fall
What is the term induction referring to?
follicular wave emergence
What are the requirements for induction using exogenous drugs?
consistent termination of existing follicular wave, predictable induction of transient increase of FSH, and normal growth of dominant follicle after selection
When using exogenous drugs for induction, what type of feedback is removing the dominant follicle?
negative feedback
What will administration of GnRH induce?
LH (importantly) and FSH secretion - it mimics the surge center
What is an important factor for GnRH to work?
the estrous cycle must be at the dominant follicle stage otherwise nothing will happe
If in the dominant follicle stage, what does GnRH do?
it causes ovulation or luteinization which will cause a new follicular wave in 1.5-2 days
What specifically happens in luteinizaiton?
the cells, in the dominant follicle, are changing from granulosa and thecal cells to luteal cells which will then release progesterone
Why would you want to get rid of the dominant follicle?
Because it will restart the follicular wave and for this wave you can predict when ovulation or the second wave will be
Can you use estradiol for follicular wave emergence?
technically it would work, but it is illegal so stay away
What exogenous drug is used to terminate the luteal phase?
prostaglandin (PGF2alpha)
Natrually, how does prostaglandin terminate the luteal phase?
Naturally, estradiol release from the ovulatory follicle stimulates oxytocin production/secretion from hypothalamus/pituitary which stimulates uterine PGF2alpha by positive feedback
When does the corpus lutem have prostaglandin receptors and when do they become functional?
it has prostaglandin receptors after 2 days post-ovulation, however, they are not primed and functional until day 5-7 after ovulation
Traditionally, when has prostaglandin been given exogenously to lyse the corpus luteum?
if it is given between day 7-17, it would lyse the CL with one dose which wwould allow for standing estrus to be seen within 2-5 days (follicle dependent)
New data has shown that prostaglandin can ve given sooner in the estrous cycle, what is that protocol?
with a 2-dose prostaglandin protocal, luteolysis can occur earlier in the estrous cycle (5-day Co-Synch + CIDR)
What does CIDR stand for?
controlled internal drug release
What drug is a key player in ensuring the luteal phase?
progesterone
What will supplementation of progesterone at >1mg/ml do?
it will cause the supression of LH, inhibiting ovulation but not inhibiting luteolysis
If you give progesterone for a period of time, then remove it, what will happen?
it will cause estrus in 2-4 days
What is the disadvantage to giving long-term progesterone?
If you give it for more than 10 dyas, there will be a decreased chance of conception on 1st estrus/ovulation
What are FSH concentrations like (levels) just before the follicular wave emergence?
FSH levels are at peak concentrations
What is the life-span of the follicular wave?
it can be 7-10 days - the average is 4 days from recruitment to dominance
What is the length of the follicular wave dependent on?
the number of waves per cycle
When does dominant follicle deviation occur?
at 8 mm
What occurs when the dominant follicle deviates?
it expresses higher receptor affinity for FSH and expresses mRNA for LH
What does dominant follicular deviation allow for?
continued growth with low FSH and preparation for ovulation
If dominance exceeds 10-12 days, what are the consequences?
There is a dramatic decrease in conception and pregnancy rates because the oocyte is aged or due to premature activation
What must we remember when utilizing prostaglandin protocols?
there must be a CL, you must give enough concentration due to metabolism in the lungs, and standing estrus usually is seen in 2-5 days dependent on dominant follicle size
