Quiz 4 Flashcards
For the synchronization protocol above what is the progesterone source?
CIDR- has progesterone in the wings
What is GnRH
Gonadotrophin-releasing hormone
directly involved in female cyclicity/ovulation
What is the purpose of the GnRH injections in this protocol?
They help the cow cycle and ovulate to be bred because of the induced LH surge
What does the abbreviation PG stand for?
Prostaglandin
What does PG do in the cow?
regresses the CL to begin cycling again
What is the reason for measuring the pelvic diameter in a 15 month replacement heifer?
You want to ensure her pelvis is wide enough to support a calf and reduce the risk of dystocia in a first calf heifer
Sexing semen is a fascinating use of technology. For a club calf or feeder calf program producing cattle to go onto a feeding program for terminal slaughter cattle, what sex of calves would be desired? What percentage of the calf crop will be the desired sex if all cows are bred using the same sexed semen?
bull calves are desired
sexed semen is 90% accurate, so about 90% of the calf crop will be male
What is one reason a purebred operation would use artificial insemination in their breeding program?
To take advantage of superior genetics, allowing the producer to compliment both the bull and the cows weaknesses and strengths to produce a top quality calf
individual mating, not group mating
You have identified a tremendous cow in your herd and would like to be able to maximize her impact in your breeding program. What reproductive tool would you use to have the greatest maternal impact on your cow herd from this single cow?
You would want to super ovulate her and use embryo transfer into recipient females
At what age should replacement heifers be bred and then at what age should those heifers calf
bred at 15 months
24 months 1st calf parturition
When using a injection PGF2a protocol to synchronize a group of cows you would typically synchronize around 60% of the cows, however 40% do not respond. Why don’t all the cows come into heat after the single injection?
PGF2a is used to regress the CL, and usually the 40% that do not respond do not have an active CL to regress in order to restart the cycle
You are using a heat check (standing heat) protocol to artificially inseminate all your cow herd properly. What is the optimum timing for insemination following the observation of a cow in standing heat?
after standing heat, bread 12 hours later
The behavioral estrus seen prior to ovulation in a cow is influenced by estradiol. Where is the estradiol originating from in the cow?
follicles on the ovary
What does the term super-ovulation refer to in an embryo transfer production?
superovulation refers to the manipulation of follicles to an excessive amount in a quality donor cow, then breeding her multiple times to produce peroral embryo that gets transferred to recipient cows.
The principle objective for manipulating the reproductive cycle is to mimic what occurs naturally. What tissue (structure) produces progesterone during the normal estrus cycle in the cow?
CL
