NEW OPPORTUNITIES TO SYNCHRONIZE NEW OPPORTUNITIES TO SYNCHRONIZE ESTRUS AND FACILITATE FIXED-TIME AIESTRUS AND FACILITATE FIXED-TIME AI
Division of Animal Sciences
University of Missouri-Columbia
July 6, 2005
DJ Patterson, MF Smith, and DJ Schafer
The current status of reproductive technology in the U.S.
beef cattle industry……
Reproductive TechnologiesReproductive Technologies Available or on the Horizon Available or on the Horizon
Estrus synchronization and AI Ultrasonography Sexed semen Embryo transfer In vitro production of embryos Transgenics (pharming) Cloning Male fertility
The U.S. Beef HerdThe U.S. Beef Herd
69% of cow-calf enterprises are secondary income sources
50% of producers report an established breeding season of specific duration
34% of beef herds are routinely pregnancy checked
10% of beef cattle enterprises utilize AI
What’s happening in adoption of technology in the beef industry on a
global basis?
Total Domestic Sales of Beef SemenTotal Domestic Sales of Beef Semen
0
200000
400000
600000
800000
1000000
1200000
1400000
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
1980
1982
1984
1986
1988
1990
1994
1996
1998
2000
1992
In the U.S. …...In the U.S. …...
Hough,, 2002
Comparison of AI Use In Beef Cattle (U.S. vs. Brazil)Comparison of AI Use In Beef Cattle (U.S. vs. Brazil)
Import and Domestic Beef Semen SalesImport and Domestic Beef Semen Sales(units sold)(units sold)
1993
1,117,798
2003
1,025,116
-8% change
1993
1,874,996
2003
4,896,204
+161% change
From NAAB, 2003; ASBIA, 2003
Unless efforts are taken to implement change in the Unless efforts are taken to implement change in the
U.S. beef cattle industry, the products of our research U.S. beef cattle industry, the products of our research
and technology may be exported to more competitive and technology may be exported to more competitive
international markets . . . . . . (Patterson et al., 2000).international markets . . . . . . (Patterson et al., 2000).
Why are we here?Why are we here?
Artificial insemination and estrus synchronization are generally regarded as the most important and applicable of all
available biotechnologies to the beef cattle industry (Seidel, 1995).
From NAHMS Survey, 1998
36
14
20 21
39
13
20 19
34
19
14
22
0
10
20
30
40
%
Estrus synchronization Artificial insemination Pregnancy diagnosis
Reasons for not Using Reproductive Procedures
Time/labor Cost Complicated Other
•Improvements in methods to synchronize estrus create the opportunity to significantly expand the use of AI in the U.S. cowherd ………………….
A unique point in time for the A unique point in time for the U.S. beef industry………U.S. beef industry………
Availability of tools and understanding of methods to control the estrous cycle in cattle
A changing market structure that recognizes and rewards quality
A unique point in time………A unique point in time………
If we don’t impact use of AI among beef producers in the U.S. in the near future, will we ever?
The challenge of transferring The challenge of transferring
technology (estrus synchronization technology (estrus synchronization
and AI) to the private sector exceeds and AI) to the private sector exceeds
the task of research and development the task of research and development
of still newer technologies……….of still newer technologies……….
CollectivelyCollectively
Adopt common terminology regarding the various estrus synchronization protocols
Identify and agree upon short lists of protocols heifers and cows heat detect and AI vs fixed-time AI
Work to overcome the attitude of “What will this cost me?” ….to… “ I’m willing to make an investment in my herd”
Effective Estrus Synchronization Programs for Beef Cattle
Facilitate AI & ET Reduce time required to detect estrus Cycling females conceive earlier in the breeding
period Induce cyclicity in peripubertal heifers and
anestrous postpartum cows
Objective: Development of highly effective & economical estrus synchronization programs
Peripubertal heifers Postpartum cows
Anestrus and estrous cycling
Excellent pregnancy rates
Products Currently Available Currently Available
Prostglandin Lutalyse, Estrumate, ProstaMate, In Synch,
EstroPlan GnRH
Cystorelin, Factrel, Fertagyl, OvaCyst Progestins
MGA CIDR
What We Know About MGA . . .What We Know About MGA . . .
ProgesteroneProgesteronePregn-4-ene-3, 20-dione
ProgesteroneProgesteronePregn-4-ene-3, 20-dione
OOCC
OO
CH3CH3
CH3CH3
CH3CH3
MGAMGA(melengestrol acetate)
6-methyl-17-alpha-acetoxy-16-methylene-pregn-4, 6-diene-3, 20-dione
MGAMGA(melengestrol acetate)
6-methyl-17-alpha-acetoxy-16-methylene-pregn-4, 6-diene-3, 20-dione
CC
OO
CH3CH3
OOCH3CH3 CH3
CH3
CH3CH3
CH3CH3
OO
OOCC
CH2CH2
What We Know About MGA . . . What We Know About MGA . . .
Induces puberty in beef heifers (Imwalle et al., 1998)
Prevents expression of behavioral estrus (Zimbelman and Smith, 1966; Imwalle et al., 2002)
Blocks the preovulatory surge of LH (Imwalle et al., 2002)
Blocks ovulation (Zimbelman and Smith, 1966; Imwalle et al., 2002)
HEIFERS
Reproductive Tract Scores (RTS)Reproductive Tract Scores (RTS)
Adapted from Anderson et al., 1991
RTS
1
2
3
4
5
Length
15
18
22
30
> 32
Height
10
12
15
16
20
Width
8
10
10
12
15
Ovarian Measurement (mm)
Description
Infantile
Prepubertal
Peripubertal
Cycling
Cycling
Uterine horns
Immature < 20 mm diameter
No tone
20-25 mm diameterNo tone
20-25 mm diameterSlight tone
30 mm diametergood tone
> 30 mm diameter
Ovarian Structures
No palpable follicles
8 mmfollicles
8-10 mmfollicles
> 10 mm folliclesCL possible
CL present
Reproductive Tract Scores (RTS) Summary
RTS
1
2
3
4
5
n
61
278
1103
494
728
Weight (lb)
594a
620b
697c
733d
755d
Pelvic Width (cm)
10.9a
11.2a
11.4b
11.7c
11.7c
Pelvic Height (cm)
13.9a
14.1a
14.5b
14.7c
14.7c
Pelvic Area (cm2)
152a
158a
166b
172c
172c
Estrous Response
(%)
54a
66b
76c
83d
86d
Adapted from Patterson and Bullock, 1995
a, b, c, d Numbers with different superscripts within a column differ (P < 0.05)
Exposed 21-d PR2 42-d PR3 TPR4
RTS1 NS5
(n)SAI6
(n)NS(%)
SAI(%)
NS(%)
SAI(%)
NS(%)
SAI(%)
1 8 55 38a 42a 63c 55c 63e 60e
2 108 661 31a 52b 54c 68d 75e 82e
3 336 3320 41a 58b 65c 74d 82e 87f
4 322 3629 48a 62b 72c 77d 91e 87f
5 242 2835 50a 64b 74c 80d 88e 88e
TOT 1016 10500 44a 61b 68c 73d 85e 87e
a,b Means within rows for 21-d PR with different superscripts differ (P < .05)c,d Means within rows for 42-d PR with different superscripts differ (P < .05)e,f Means Within rows for TPR with different superscripts differ (P < .05)From Randle and Patterson, 2005
Comparison of reproductive performance in herds using natural service or Comparison of reproductive performance in herds using natural service or synchronization and AI on replacement heifers by RTSsynchronization and AI on replacement heifers by RTS
MGA (14 days)
11 14 16 20 14 16 20 31 33 36 31 33 36
PGPG
Synchronizedestrus
Treatment days
Estrus
Brown et al., 1988
MGA-PG14-19 d
Improved estrous responseImproved estrous response More heifers in heatMore heifers in heat
Similar fertilitySimilar fertility No change in conception or pregnancy rateNo change in conception or pregnancy rate
Improved synchronyImproved synchrony More heifers in heat in a shorter timeMore heifers in heat in a shorter time
(Deutscher et al., 2000; Lamb et al., 2000)
MGA (14 days)
1 14 33
PG
Wood et al., 2001
MGA-PG
Treatment days
MGA (14 days)
1 14 26 33
PGGnRHMGA Select
0
5
10
15
20
25
30
35
15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
Day of treatment
Fol
licl
e d
iam
eter
(m
m)
ESTRUSESTRUS
PG
Wood et al., 2001
0
5
10
15
20
25
30
35
15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
Day of treatment
Fol
licl
e d
iam
eter
(m
m)
ESTRUSESTRUS
PGGnRH
Wood et al., 2001
When to Add GnRH When to Add GnRH to an MGA-PG Protocol for Heifersto an MGA-PG Protocol for Heifers
Consideration of . . . . Age Weight Reproductive tract score (RTS)
Pubertal status
Wood et al., 2000; Kojima et al., 2001
How do MGA- and CIDR-based How do MGA- and CIDR-based protocols compare in heifers?protocols compare in heifers?
1 14 26 33
MGA (14 days)
1 14 23 30
Treatment day
.. .. 12 days .. .. .. .. 7 days .. ..
.. .. 9 days .. .. .. .. 7 days .. ..
GnRH
GnRH
PG
PG
Experimental ProtocolsExperimental Protocols
Kojima et al., 2004
CIDR (14 days)
MGA Select
14-d CIDR
Experimental Procedures
352 yearling crossbred beef heifers at three locations
Location 1 n = 154 (Southeast Missouri)Location 2 n = 113 (North Dakota)
Location 3 n = 85 (North central Missouri)
Heifers were assigned to one of two treatments (MGA or CIDR) by age and weight
Kojima et al., 2004
0 1 2 3 4 5+
Days after PG
% o
f H
eife
rs I
nse
min
ated
Summary for Timing of AISummary for Timing of AI
No treatment x location effect (P > 0.10); therefore, data were pooled
Distribution of AI dates were different between MGA- and CIDR-treated heifers (P < 0.02)
0
10
20
30
40
50
60
70
80CIDR (n = 177)
MGA (n = 175)
0% 1%
10% 15%
69%
53%
5%
10%16%
21%PG
Kojima et al., 2004
112/177 (63 %)a
83/175 (47 %)b
195/352 (55 %)
AI Pregnancy
a, b P = 0.01+ 16 %
CIDR
MGA
Total
154/177 (87 %)
147/175 (84 %)
301/352 (86 %)
Estrous Response
Estrous Response, AI Pregnancy, and Final Estrous Response, AI Pregnancy, and Final Pregnancy RatesPregnancy Rates
+ 3 %Diff.
164/177 (93 %)
159/175 (91 %)
323/352 (92 %)
FinalPregnancy
+ 2 % Kojima et al., 2004
SummarySummary
In yearling beef heifers:
CIDR-GnRH-PG improved synchrony of estrus compared with MGA Select
CIDR-GnRH-PG improved AI pregnancy rate over MGA Select
Kojima et al., 2004
COWS
How do MGA-based protocols perform in synchronizing estrus in mixed populations of postpartum
beef cows? (estrous cycling and anestrus)
Precise control of the bovine estrous cycle requires the synchronization of both luteal and follicular functions.
Protocols
1 14 26 33
MGA (14 days)
Treatment day
MGA Select
MGA
7-11 Synch
1 7 11 18
PGGnRH
PGGnRH
PG
Kojima et al., 2000; Wood et al., 2001
These protocols were hypothesized to……These protocols were hypothesized to……
Improve estrous response and pregnancy rates
during the synchronized period
Effectively synchronize estrus in estrous cycling cows
Induce cyclicity in anestrous cows
Prevent short cycles among anestrous cows
induced to ovulate
These protocols were hypothesized to……These protocols were hypothesized to……
Reduce the period of time required to detect estrus
Facilitate fixed-time AI
How do MGA Select and 7-11 Synch How do MGA Select and 7-11 Synch compare on the basis of synchronized compare on the basis of synchronized
estrus and pregnancy rates in postpartum estrus and pregnancy rates in postpartum beef cows with AI performed on the basis beef cows with AI performed on the basis
of of detecteddetected estrusestrus??
MGA Select vs. 7-11 SynchMGA Select vs. 7-11 SynchAI performed after detected estrusAI performed after detected estrus
No difference in estrous response
Improvement in synchrony of estrus among 7-11 Synch treated cows (P < 0.01)
No difference in synchronized conception or pregnancy rates
No difference in final pregnancy rate
Stegner et al., 2004
0
5
10
15
20
25
30
35
40
45
0 12 24 36 48 60 72 84 96 108 120 132 144 NR
Time after PG, h
Co
ws
in e
stru
s, n
oMGA Select
7-11 Synch
Stegner et al., 2004
Pregnancy rateNo. (%)
MGA SelectPatterson et al., 2001 67/103 65Patterson et al., 2002 67/101 66Stegner et al., 2003 61/109 56Combined total 195/313 62
7-11 Synch Kojima et al., 2001 30/44 68Stegner et al., 2003 71/111 64Combined total 101/155 65
Pregnancy Rates of Cows Inseminated Pregnancy Rates of Cows Inseminated after Detected Estrusafter Detected Estrus
How do MGA Select and 7-11 Synch How do MGA Select and 7-11 Synch compare on the basis of pregnancy rates in compare on the basis of pregnancy rates in
postpartum beef cows inseminated at postpartum beef cows inseminated at predeterminedpredetermined fixedfixed timestimes??
MGA Select
72 hr
80 hr
72 hr
48 hr
Time of AI after PG
64%
50% Stegner et al., 2003
61%Perry et al., 2002
46%Stevenson et al., 2003
Pregnancy rate
7-11 Synch
61%60 hrUnpublished data., 2002
52%
59%
48 hr
60 hrKojima et al., 2003
63%60 hrKojima et al., 2003
63%60 hrKojima et al., 2002
72%48 hrHixon et al., 2001
Pregnancy rate
Time of AI after PG
Bader et al. (2004) compared pregnancy rates resulting from fixed-time AI among suckled beef cows assigned to the MGA Select or 7-11 Synch protocols.
ProtocolsProtocols
1 14 26 33 … … … 72 hr
MGA (14 days)
Treatment day
MGA Select
MGA
7-11 Synch
1 7 11 18 … … 60 hr
PG
PGGnRH
PG
AI
GnRH
GnRH
GnRH
AI
Bader et al., 2004
Location
Days
postpartum
Body
condition score Estrous cycling
No. %
1 50 ± 1.0a 5.8 ± 0.1a 64/208 31a
2 39 ± 1.3b 5.8 ± 0.1a 31/122 25a,b
3 36 ± 1.5b 5.4 ± 0.1b 18/92 20b
Combined 42 d 5.7 113/422 27
Days postpartum, body condition score, and estrous-cycling status prior to initiation of synchronization treatments
a,b(P < 0.05)
Bader et al., 2004
Location Treatment Fixed-time AI Final
No. % No. %
17-11 Synch 64/104 62 95/104 91
MGA Select 68/104 65 101/104 97
27-11 Synch 34/60 57 57/59 97
MGA Select 43/62 69 60/62 97
37-11 Synch 30/45 67 43/45 96
MGA Select 31/47 66 42/47 89
Combined7-11 Synch 128/209 61 195/208 94
MGA Select 142/213 67 203/213 95
Fixed-time AI and final pregnancy rates
Bader et al., 2004
MGA Select 7-11 Synch
Cycling Anestrus Cycling Anestrus
Location No. Preg % No. Preg % No. Preg % No Preg %
1 20/30 67 48/74 65 24/34 71 40/70 57
2 12/16 75 31/46 67 9/15 60 25/45 56
3 6/8 75 25/39 64 8/10 80 22/35 63
Combined 38/54 70 104/159 65 41/59 69 87/150 58
Fixed-time AI pregnancy rate based on pretreatment estrous cyclicity status
Bader et al., 2004
Pros and Cons
MGA Select - effective in mixed - treatment length populations - MGA intake - synchrony of estrus - fertility after treatment 7-11 Synch - effective in mixed - multiple populations animal handlings - exceptional synchrony - drug costs of estrus - MGA intake - fertility after treatment - treatment duration
Advantages Disadvantages
Pregnancy rateNo. (%)
7-11 Synch Detected estrus 101/155 65Fixed-time AI 446/728 61
MGA SelectDetected estrus 195/313 62Fixed-time AI 281/436 64
Pregnancy rates after AI based on detected estrus Pregnancy rates after AI based on detected estrus or at predetermined fixed timesor at predetermined fixed times
Implications
This sequential approach to estrous cycle control (progestin-GnRH-PG) effectively synchronizes estrus with resulting high fertility among mixed populations of estrous cycling and anestrous postpartum beef cows.
How do MGA- and CIDR-based protocols compare on the basis of
pregnancy rates in postpartum beef cows inseminated at
predetermined fixed times?
1 14 26 33………
0 7……….
MGA (14 d)
GnRH
MGA Select vs. CO-Synch + CIDRMGA Select vs. CO-Synch + CIDRSchafer, 2005
Treatment day
PG
GnRH PG
GnRH
AI
GnRH
AI
CIDR (7 d)
Timing of InseminationTime of AI Pregnancy
Protocol after PG rate MGA SelectStevenson et al., 2003 48 h 46%Perry et al., 2002 72 h 61%Bader, 2004 72 h 67%Stegner et al., 2004 72 h 64%
80 h 50%
CO-Synch + CIDRLamb et al., 2000 48 h 56%
48 h 56%Bremer et al., 2004 54 h 67%
66 h 71%
Larson et al., 2004 60 h 54%
1 14 26 33 …… 72h
0 7 …... 66h
MGA (14 d)
GnRH
MGA Select vs. CO-Synch + CIDRMGA Select vs. CO-Synch + CIDRSchafer, 2005
Treatment day
CIDR (7 d)
PG
GnRH PG
AI
GnRH
GnRH
AI
Experimental ProceduresExperimental ProceduresSchafer, 2005Schafer, 2005
Animals: Crossbred, suckled, beef cows (n = 650) at four locations were assigned to treatment within age groups by calving date and BCS
Experimental ProceduresExperimental ProceduresSchafer, 2005Schafer, 2005
Four different AI sires were used Location 1 = 3 Location 2 = 1 Location 3 = 1 Location 4 = 1
One of the sires that was used at location 1 was the same sire used at Locations 3 & 4
Experimental ProceduresExperimental ProceduresSchafer, 2005Schafer, 2005
Cows were exposed to fertile bulls 14 d after AI
Pregnancy rate to fixed-time AI was determined with ultrasound 40 – 45 d after insemination
Location
Days
postpartum
Body
condition score
Estrous cycling
No. %
1 46 5.7 112/210 53
2 33 6.0 63/158 40
3 44 5.3 31/88 35
4 43 5.3 156/194 80
Combined 42 d 5.5 362/650 56
Number of cows at each location, DPP, BCS, and estrous-cycling status prior to initiation of synchronization treatments
(Schafer, 2005)
Fixed-time AI pregnancy rates between treatments and among locations (Schafer, 2005)
Location Treatment Fixed-time AI
No. %
1MGA Select 70/106 66
CO-Synch+CIDR 67/104 64
2MGA Select 53/80 66
CO-Synch+CIDR 56/78 72
3MGA Select 26/45 58
CO-Synch+CIDR 29/43 67
4MGA Select 52/96 54
CO-Synch+CIDR 62/98 61
Pregnancy rates to fixed-time AI Pregnancy rates to fixed-time AI Schafer, 2005Schafer, 2005
Pregnancy rate
Treatment No. %
MGA Select 201/327 61
CO-Synch+CIDR 214/323 66
MGA® Select CO-Synch+CIDR
Cycling Anestrus Cycling Anestrus
Location No. Preg % No. Preg % No. Preg % No Preg %
1 38/62 61 32/44 73 30/50 60 37/54 69
2 20/29 69 33/51 65 25/34 74 31/44 70
3 11/16 69 15/29 52 8/15 53 21/28 75
4 41/78 53 11/18 61 50/78 64 12/20 60
Combined 110/185 59 91/142 64 113/177 64 101/146 69
Fixed-time AI pregnancy rate based on pretreatment estrous cyclicity status (Schafer, 2005)
Conclusions Conclusions Schafer, 2005Schafer, 2005
The results from this experiment demonstrate that comparable pregnancy rates to fixed-time AI can be achieved using the MGA Select or CO-Synch+CIDR protocols to synchronize estrus in postpartum beef cows.
Do we know what to expect at calving Do we know what to expect at calving from cows that conceive on the same from cows that conceive on the same
day to the same sire?day to the same sire?
0
5
10
15
20
25
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5
0
5
10
15
20
25
-11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 40
5
10
15
20
25
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9
0
5
10
15
20
25
-11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6
Days relative to 285 d gestation due date; Bader et al., 2004
% o
f A
I ca
lves
bor
n
0
5
10
15
20
25
-13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8
A; Angus; +6.2 BW272-292, 20 d
B; Angus; +3.3 BW275-292, 17 d
C; Red Angus; –1.5 BW, 2 CED274-289, 15 d
D; Simmental; -0.6 BW, +14.8 CE275-294, 19 d
B; Angus; +3.3 BW274-291, 17 d
0
2
4
6
8
10
12
14
16
18
20
-14 -12 -10 -8 -6 -4 -2 0 2 40
2
4
6
8
10
12
14
16
18
20
-10 -8 -6 -4 -2 0 2 4 6 80
2
4
6
8
10
12
14
16
18
20
-11 -9 -7 -5 -3 -1 1 3 5 7
0
2
4
6
8
10
12
14
16
18
20
-12 -8 -6 -3 0 3 6 9 12 150
2
4
6
8
10
12
14
16
18
20
-13 -11 -9 -7 -5 -3 -1 1 3 5 7 90
2
4
6
8
10
12
14
16
18
20
-10 -8 -6 -4 -2 0 2 4 6 8
Location 1; Sire A (Angus) BW EPD -0.3; CED = +11 Range 271-290 Mean = 281
Location 1; Sire B (Angus) BW EPD +3.5; CED = +6 Range 275-292 Mean = 281
Location 1; Sire C (Angus) BW EPD -1.1; CED = +11 Range 274-287 Mean = 281
Location 2; Sire D (Red Angus) BW EPD +2.3; CED = -2 Range 273-300 Mean = 283
Location 3; Sire B (Angus) BW EPD +3.5; CED = +6 Range 272-294 Mean = 283
Location 4; Sire B (Angus) BW EPD +3.5; CED = +6 Range 275-294 Mean = 284
0
2
4
6
8
10
12
271 274 277 280 283 286 289 292 295 298
Day of Gestation
% o
f A
I si
red
cal
ves
Location 1; Sire A Location 1; Sire B Location 1; Sire C
Location 2; Sire D Location 3; Sire B Location 4; Sire B
Calving Distribution of AI sired calves (Schafer et al., 2005)
Consider the impact of estrus synchronization on calving distribution………
Opportunities for increasing profits lie in managing females from the later calving intervals forward toward the first and second calving intervals.
High production herds see 61% of the calves born by day 21, 85% by day 42 and 94% by day 63.
Hughes, 2005
First 15 d First 30 d0
102030405060708090
100 MGA Select7-11 Synch
Calving period
Cow
s ca
lvin
g, %
Stegner et al., 2004
0
1
2
3
4
5
6
7
8
%
1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77
Day of calving season
Calving distribution for locations 1, 2, & 3 (Schafer, 2005)
Cumulative Calf % by:
day 15 = 64%
day 21 = 70%
day 30 = 77%
day 42 = 91%
0102030405060708090
100
2004 2005
MU Forage Systems Research Center cumulative calf crops
0
10
20
30
40
50
60
70
80
90
100
1 16 31 46
Day of calving season
Per
cen
tag
e
Natural Service (3 years; n = 526) Estrus Detection & AI (5 years; n = 1040)Fixed-time AI (2 years; n = 397)
Cumulative calf crops (MU Thompson Farm) for the first 46 days over 10 calving seasons
Conclusions and ImplicationsConclusions and Implications
Estrous response and fertility in postpartum beef cows after treatment with various estrus synchronization protocols.
Treatment Estrous response Pregnancy rate
AI based on
detected estrus No. % No. %
* DeJarnette and Wallace
2 shot PGSelect Synch*MGA-PGMGA Select7-11 Synch
241/422 57353/528 67305/408 75275/313 88142/155 92
147/422 35237/528 45220/408 54195/313 62101/155 65
Fixed-time AIMGA Select7-11 SynchCO-Synch + CIDR
482/763 63446/728 61214/323 66
Estrous response and fertility in postpartum beef cows after treatment with various estrus synchronization protocols.
Treatment Estrous response Pregnancy rate
AI based on detected estrus No. % No. %
* DeJarnette and Wallace
2 shot PGSelect Synch*MGA-PGMGA Select7-11 Synch
241/422 57353/528 67305/408 75275/313 88142/155 92
147/422 35237/528 45220/408 54195/313 62101/155 65
Fixed-time AIMGA Select7-11 SynchCO-Synch + CIDR
482/763 63446/728 61214/323 66
CO-Synch + CIDR Results (FTAI @ 66 hr after PG)
Herd (Year) No. Pregnant Total No. Percentage
1 (F03) 41 51 80
2 (S04) 67 104 64
3 (S04) 56 78 72
4 (S04) 29 43 67
5 (S04) 52 96 63
6 (S04) 60 90 67
7 (F04) 31 48 65
8 (F04) 87 143 61
9 (F04) 61 100 61
10 (F04) 44 69 63
11 (F04) 68 111 61
12 (F04) 47 60 78
13 (S05 143 224 64
Total 786 1217 65
• Research is underway to develop new protocols for heifers that will facilitate fixed-time AI ….
• The technology now exists to successfully inseminate postpartum beef cows at predetermined fixed times with resulting high pregnancy rates . . . . . . . . .
• Improvements in methods to synchronize estrus create the opportunity to significantly expand the use of AI in the U.S. cowherd . . . . . . .
AcknowledgementsAcknowledgementsFaculty, Students, & StaffFaculty, Students, & Staff
Jon Bader Dr. George Perry Roger Eakins Daniel SchaferDr. Mark Ellersieck Jon SchrefflerFreddie Kojima Dr. Mike SmithDr. Matthew Lucy Jacob StegnerDavid McAtee Stacey Wood
(Follis)
AcknowledgementsAcknowledgements
Research Support Cooperators
Select Sires, Inc. 4-M Ranch
KABA/Select Sires, Inc. John Ranch
ABS Global Jim Wallis Farms
Merial Jim Clement, DVM
Pfizer Animal Health SEMO University
USDA-NRI MFA, Inc.
MU Farms & Centers
AcknowledgementsAcknowledgements
Beef Reproduction Leadership Team
AI industry
Pharmaceutical industry
Veterinary practitioners
North Central Region Bovine Reproduction Task Force
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