Bovine Therio: Estrus synchronization

Question 1

Why estrus synchronization in beef herds

Answer 1

For genetic improvement
Use of AI and embryo transfer technology

Question 2

______________ is one of the most important factors in estrus synchronization in dairy cattle

Answer 2

Heat detection

Question 3

Methods that improve estrus (heat) detection

Answer 3

PGF2a and analogues
Controlled internal drug releasing device (CIDR)

Question 4

PGF2a and analogues (estrus improvement)

Answer 4

1 injection and heat detection and AI
2 injections 11 and 14 days a a part: heat detection and AI or between 72 and 80 then 12 hours after heat detection

Question 5

CIDR

Answer 5

Insertion for 7 days (progesterone, regulates follicular waves and negative feedback on LH)
1 day prior to removal admin PGF2a (lyse CL) →heat detection and AI

Question 6

Group 1 @ 2nd PGF2a (day 14-18)

Answer 6

Won’t respond to the first PGF2a
Will be between 14-18 days of the cycle @ the time of the second injection of PGF2a

Question 7

Group 2 @ 2nd PGF2a (days 8-10)

Answer 7

Will respond to the first PGF2a and be in estrus 2-5 days after
Cows between days 8-10 @ time of second injection
Will have mature CL

Question 8

Group 3 @ 2nd PGF2a (days 10-14)

Answer 8

Won’t respond to the first PGF2a
Come into estrus on their own between days 10-14 of cycle @ time of second injection
Will have a mature CL

Question 9

Methods that bypass estrus (heat) detection

Answer 9

PGF2a or analougues
Ovsynch
CIDR + Ovsynch

Question 10

PGF2A or analougues (bypass estrus)

Answer 10

2 injections 11-14 days apart @ 80 hrs
AI @ 72 hours and 96 hours after second injection

Question 11

Ovsynch

Answer 11

Days 0: GnRH
Day 7: PGF2a
Day 10: GnRH then insemination 16hrs later

Question 12

CIDR + ovsynch

Answer 12

Days 0: GnRH +CIDR placement
Day 7: CIDR removal + PGF2a
Day 10: GnRH then insemination 12hrs later

Question 13

First GnRH of Ovsynch

Answer 13

Synchronizes follicular waves and induces ovulation or luteinization of the dominant follicle

Question 14

PGF2a of Ovsynch

Answer 14

Lyses CL or the luteinized follicle

Question 15

Second GnRH of Ovsynch

Answer 15

Induce ovulation in all cows with mature follicle