Bovine Estrus Synchronization

Question 1

How long is the bovine Estrus Cycle?

Answer 1

21 Days

Question 1

How long is each phase of the Estrus Cycle?
Estrus:
Metestrus:
Diestrus:
Proestrus:

Answer 1

Estrus: 12-18hrs (Shorter dairy 7hr)
Metestrus: 3-4 days
Diestrus: 14 days (CL)
Proestrus: 2-3 days

Question 2

Estrogen is produced by what structure?

Answer 2

Follicle

Question 3

Progesterone is produced by what structure?

Answer 3

Cl

Question 4

LH is produced by what structure?

Answer 4

Anterior Pituitary

Question 5

FSH is produced by what structure?

Answer 5

Anterior Pituitary

Question 6

PGF2 Alpha - Prostaglandin is produced by what structures? What does it do?

Answer 6

Endometrium (uterus) and go to CL
Lyse the Cl

Question 7

What stimulates ovulation and resets the follicular wave?

Answer 7

GNRH (Triggers follicle growth and LH surge)

Question 8

How long after an inject of Lutalyse (Prostaglandin) will ovulation occur?

Answer 8

3 days

Question 9

What does a CIDR (Progesterone) do?

Answer 9

Prevents ovulation

Question 10

What does CIDR stand for?

Answer 10

Controlled Intravaginal Drug Release

Question 11

What does GNRH do to the estrogen cycle?

Answer 11

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

Question 12

How soon after injecting GNRH does a new wave begin?

Answer 12

1.5-2 days

Question 13

What are some factors you should consider when creating a synch program?

Answer 13

Cost (product and labor), efficiency, facilities, BCS female, postpartum interval cow and producer objective

Question 14

What is one of the most important factors of any synch protocol?

Answer 14

Timing!

Question 15

Select Synch Protocol:

Answer 15

Day 1: Monday - GNRH (+/- CIDR)
Day 7: Monday - PGF2 (Remove CIDR)
Day 6-13: Watch for heat and AI

Question 16

Ovsynch Protocol:

Answer 16

Day 1: Monday - GNRH (+/- CIDR)
Day 7: Monday - PGF2 and remove CIDR
Day 9: Wednesday - GNRH
Day 9/10: TAI (12-18hr post GNRH)

Question 17

Why can an ovsynch 48 be beneficial over an ovsynch 56 in dairy cows?

Answer 17

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

Question 18

Cosynch protocol:

Answer 18

Day 1: Monday - GNRH +/- CIDR
Day 7: Monday - PGF2
Day 9-10: Wednesday/Thursday - GNRH and TAI

Question 19

What group of cattle is ovsynch commonly used for?

Answer 19

Dairy

Question 20

What type of cattle is cosynch commonly used for?

Answer 20

Beef

Question 21

What is the difference between Cosynch and Ovsynch?

Answer 21

Ovsych GNRH is given 8-18 hours before AI
Cosycn GNRH is given with AI

Question 22

In a resynchronization protocol, is it safe to start before PD?

Answer 22

Yes, GNRH wont hurt a baby, and will save time, but do waste money on cows that are not open

Question 23

What is significant about the heifer protocols?
Beef 14d CIDR PG TAI
0- CIDR
14 - Out
30 - PG
33 - GNRH and TAI

Answer 23

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

Question 24

Why is split time AI used for sexed semen?

Answer 24

Sexed semen is more expensive and manipulated do it needs to be inseminated as close to ovulation as possible. Give to cows in estrus.