Assisted Reproductive Technology

1
Assisted Reproductive Technology

• Chapter 12

2
Ovsynch
GnRH
AI
PG
GnRH
9
1
7
16-24hr
CO-Synch
GnRHAI
PG
GnRH
1
7
9
Select Synch
PG
GnRH
----
---Heat detection AI--
Methods currently being used to synchronize
ovulation I postpartum beef cows Ovsynch,
Co-Synch and Select Synch.
3
Estrus
Natural services
MGA (14 days)
1
16
20
24
14
MGA and natural services (adapted from Patterson
et al., 2000)
4
Synchronized estrus
Estrus
PG
MGA (14 days)
1
14
16
20
33
35
38
MGA-PG protocol (adapted from Brown et al., 1988
Lamb et al., 2000)
5
MGA Select
GnRH
PG
MGA (14 days)
1
14
26
33
Treatment Days
The MGA Select protocol. MGA is fed for a period
of 14 days following in 12 days (day 26) by an
injection of GnRh, and PG 19 days after MGA
withdrawal (day 33).
MGA is a registered trademark of Pharmacia
Animal Health
6
MGA-PG
PG
MGA (14 days)
14
26
33
1
MGA-GnRh-PG
GnRH
PG
MGA (14 days)
1
14
26
33
Treatment Days
Cows were fed MGA for 14 days 19 days after MGA
withdrawal PG was administered to all cows. GnRH
was administered to 1/2 of the cows 7 days prior
to PG (Patterson et al., 2001).
7
GnRH AI
MGA-GnRH-PG-GnRH
PG
GnRH
MGA (14 d)
14
26
33
36
1
GnRH AI
CO-Synch (modified)
GnRH
PG
Carrier (14 d)
1
14
26
33
36
Treatment Days
(72 hr)
Treatment schedules and timing of fixed-time
insemination for MGA- treated and Control
(modified Co-Synch) cows (Perry et al., 2001).
8
Follicular development
Ovulation or luteinization
Synchronized ovulation
PG
Synchronized initiation of a new follicular
wave
GnRH
PG
MGA
1
14
11
18
Treatment Days
Illustration of the treatment schedule and events
associated with the 7-11 Synch protocol (Kojima
et al., 2000).