Bovine Estrus Synchronization Flashcards
How long is the bovine Estrus Cycle?
21 Days
How long is each phase of the Estrus Cycle?
Estrus:
Metestrus:
Diestrus:
Proestrus:
Estrus: 12-18hrs (Shorter dairy 7hr)
Metestrus: 3-4 days
Diestrus: 14 days (CL)
Proestrus: 2-3 days
Estrogen is produced by what structure?
Follicle
Progesterone is produced by what structure?
Cl
LH is produced by what structure?
Anterior Pituitary
FSH is produced by what structure?
Anterior Pituitary
PGF2 Alpha - Prostaglandin is produced by what structures? What does it do?
Endometrium (uterus) and go to CL
Lyse the Cl
What stimulates ovulation and resets the follicular wave?
GNRH (Triggers follicle growth and LH surge)
How long after an inject of Lutalyse (Prostaglandin) will ovulation occur?
3 days
What does a CIDR (Progesterone) do?
Prevents ovulation
What does CIDR stand for?
Controlled Intravaginal Drug Release
What does GNRH do to the estrogen cycle?
If no CL is present, then it will lead to an LH surge and ovulation
If a CL is present, then it will lead to atresia of one follicular wave and a new cohort of follicles as a second wave
How soon after injecting GNRH does a new wave begin?
1.5-2 days
What are some factors you should consider when creating a synch program?
Cost (product and labor), efficiency, facilities, BCS female, postpartum interval cow and producer objective
What is one of the most important factors of any synch protocol?
Timing!
Select Synch Protocol:
Day 1: Monday - GNRH (+/- CIDR)
Day 7: Monday - PGF2 (Remove CIDR)
Day 6-13: Watch for heat and AI
Ovsynch Protocol:
Day 1: Monday - GNRH (+/- CIDR)
Day 7: Monday - PGF2 and remove CIDR
Day 9: Wednesday - GNRH
Day 9/10: TAI (12-18hr post GNRH)
Why can an ovsynch 48 be beneficial over an ovsynch 56 in dairy cows?
Because the 48 allows the farmer to stick to the morning for every set of injections and AI making it less likely to forget and can be paired with milking
Cosynch protocol:
Day 1: Monday - GNRH +/- CIDR
Day 7: Monday - PGF2
Day 9-10: Wednesday/Thursday - GNRH and TAI
What group of cattle is ovsynch commonly used for?
Dairy
What type of cattle is cosynch commonly used for?
Beef
What is the difference between Cosynch and Ovsynch?
Ovsych GNRH is given 8-18 hours before AI
Cosycn GNRH is given with AI
In a resynchronization protocol, is it safe to start before PD?
Yes, GNRH wont hurt a baby, and will save time, but do waste money on cows that are not open
What is significant about the heifer protocols?
Beef 14d CIDR PG TAI
0- CIDR
14 - Out
30 - PG
33 - GNRH and TAI
The CIDR jump starts their cycle and then you give them time to go through their first estrus Cycle (shorter than normal), then catch them on the next
Why is split time AI used for sexed semen?
Sexed semen is more expensive and manipulated do it needs to be inseminated as close to ovulation as possible. Give to cows in estrus.
