Results with Timed AI Systems

• Syncro - Mate B 35-50% Preg– Highly Variable– Depends on stage of cycle

• OvSynch 40-60% Preg– Less variable

• Co-synch 40-50% Preg– Still working out details

Estrus Detection and AI Systems

1 3114 37

MGA-PGF System

Feed MGA

Estrus & Breed

PGF

Do Not Breed

0 7 12

GnRH PGF

SELECT-SYNCH System

Estrus & Breed

0 9 7 14

Nor + E2

Remove implant

SYNCRO - MATE B System

ImplantEstrus &

Breed

MGA+PGF and Syncro-Mate B

• MGA+PGF was better in synchronizing heifers – 57.3% vs 36.6%

• MGA+PGF in large field studies in KY produced conception rates of 58.3%

• Synchronization rate with SMB generally from 35 - 50 %

MGA + PGF vs PGF

0

10

20

30

40

50

60

70

80

90

Pregnancy

rate

%

MGA+PGF2X PGF

Patterson et al., 1995

Select Synch vs PGF

0

5

10

15

20

25

30

35

40

45

% Pregnant

PGFSelect

Results from Estrus Detection + AI Systems

• MGA + PGF best system for heifers

• MGA +PGF resulted in increased fertility in some studies

• Syncro-Mate B highly varaible

• Select-synch looks promising, but also variable

Experimental Systems

0 7 12

GnRH PGF

GnRH-NOR-PGF System

Progestin

Estrus & Breed

0 7 15

PGF

PROG-PGF-E2 System

Progestin

Estrus & Breed

E2

9

Recommendations

• Current estrous synchronization systems can enhance AI success especially in anestrous postpartum cows

• Systems using GnRH have some advantages over older systems

• Including progestins in GnRH systems may further improve conception rates to synchronized estrus