Bovine - Female Pharmacology

Question 1

Note… see flip side

Answer 1

Dr. Dohlman said that he would give us the protocols so this flashcard set is the basics of estrus sychronization

Question 2

What are the advantages of estrus synchronization?

Answer 2

reduce time and labor, efficiency use of ART (AI + ET), group breeding/calving, and decrease bull utilization

Question 3

What are the disadvantages of estrus synchronization?

Answer 3

cost of drugs, use of drugs, group calving, reduced conception rates, and planning

Question 4

What is the goal of estrus sychronization?

Answer 4

to synchronize the group to the same phase of the estrous cycle (timing)

Question 5

What does FTAI stand for?

Answer 5

fixed time artificial insemination

Question 6

What does FTET stand for?

Answer 6

fixed time embryo transfer

Question 7

What are the four important factors for controlling the estrous cycle?

Answer 7

synchronizing emergence of new follicular wave, terminate luteal phase, maintain the luteal phase, or synchronizing ovulation

Question 8

What is defined by the degree of synchronization?

Answer 8

The speed at which progesterone falls and the maturity of the dominant follicle at the progesterone fall

Question 9

What is the term induction referring to?

Answer 9

follicular wave emergence

Question 10

What are the requirements for induction using exogenous drugs?

Answer 10

consistent termination of existing follicular wave, predictable induction of transient increase of FSH, and normal growth of dominant follicle after selection

Question 11

When using exogenous drugs for induction, what type of feedback is removing the dominant follicle?

Answer 11

negative feedback

Question 12

What will administration of GnRH induce?

Answer 12

LH (importantly) and FSH secretion - it mimics the surge center

Question 13

What is an important factor for GnRH to work?

Answer 13

the estrous cycle must be at the dominant follicle stage otherwise nothing will happe

Question 14

If in the dominant follicle stage, what does GnRH do?

Answer 14

it causes ovulation or luteinization which will cause a new follicular wave in 1.5-2 days

Question 15

What specifically happens in luteinizaiton?

Answer 15

the cells, in the dominant follicle, are changing from granulosa and thecal cells to luteal cells which will then release progesterone

Question 16

Why would you want to get rid of the dominant follicle?

Answer 16

Because it will restart the follicular wave and for this wave you can predict when ovulation or the second wave will be

Question 17

Can you use estradiol for follicular wave emergence?

Answer 17

technically it would work, but it is illegal so stay away

Question 18

What exogenous drug is used to terminate the luteal phase?

Answer 18

prostaglandin (PGF2alpha)

Question 19

Natrually, how does prostaglandin terminate the luteal phase?

Answer 19

Naturally, estradiol release from the ovulatory follicle stimulates oxytocin production/secretion from hypothalamus/pituitary which stimulates uterine PGF2alpha by positive feedback

Question 20

When does the corpus lutem have prostaglandin receptors and when do they become functional?

Answer 20

it has prostaglandin receptors after 2 days post-ovulation, however, they are not primed and functional until day 5-7 after ovulation

Question 21

Traditionally, when has prostaglandin been given exogenously to lyse the corpus luteum?

Answer 21

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)

Question 22

New data has shown that prostaglandin can ve given sooner in the estrous cycle, what is that protocol?

Answer 22

with a 2-dose prostaglandin protocal, luteolysis can occur earlier in the estrous cycle (5-day Co-Synch + CIDR)

Question 23

What does CIDR stand for?

Answer 23

controlled internal drug release

Question 24

What drug is a key player in ensuring the luteal phase?

Answer 24

progesterone

Question 25

What will supplementation of progesterone at >1mg/ml do?

Answer 25

it will cause the supression of LH, inhibiting ovulation but not inhibiting luteolysis

Question 26

If you give progesterone for a period of time, then remove it, what will happen?

Answer 26

it will cause estrus in 2-4 days

Question 27

What is the disadvantage to giving long-term progesterone?

Answer 27

If you give it for more than 10 dyas, there will be a decreased chance of conception on 1st estrus/ovulation

Question 28

What are FSH concentrations like (levels) just before the follicular wave emergence?

Answer 28

FSH levels are at peak concentrations

Question 29

What is the life-span of the follicular wave?

Answer 29

it can be 7-10 days - the average is 4 days from recruitment to dominance

Question 30

What is the length of the follicular wave dependent on?

Answer 30

the number of waves per cycle

Question 31

When does dominant follicle deviation occur?

Answer 31

at 8 mm

Question 32

What occurs when the dominant follicle deviates?

Answer 32

it expresses higher receptor affinity for FSH and expresses mRNA for LH

Question 33

What does dominant follicular deviation allow for?

Answer 33

continued growth with low FSH and preparation for ovulation

Question 34

If dominance exceeds 10-12 days, what are the consequences?

Answer 34

There is a dramatic decrease in conception and pregnancy rates because the oocyte is aged or due to premature activation

Question 35

What must we remember when utilizing prostaglandin protocols?

Answer 35

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