control of estrus in cows - applied reproductive strategies in beef
TRANSCRIPT
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Control of Estrus in Cows
Cliff Lamb
University of Florida
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Estrous Synchronization and AI in Beef Cattle
Definitions
Synchronization Rate: % of females detected in estrus compared to total number synchronized.
Conception Rate: % of females pregnant compared to number of females inseminated.
Pregnancy Rate: % of females pregnant compared to total number synchronized.
Effect of synchronization rate on pregnancy rates
Effect of synchronization rate on pregnancy rates Location Effects
(Larson et al., 2006)
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Focus on Fixed-Time AI (TAI) in Cows
PGF GnRH TAI & GnRH
-7 d 0 60-66 h
CIDR
7-day CO-Synch + CIDR
PGF GnRH TAI & GnRH
-5 d 0 8 ± 2h 72 h
CIDR
5-day CO-Synch + CIDR
PGF
PGF GnRH TAI & GnRH
-7 d 0 60-66h
CIDR
7-day CO-Synch + CIDR
PGF GnRH TAI & GnRH
-5 d 0 8±2h 72h
CIDR
5-day CO-Synch + CIDR
PGF
Pregnancy rates
58 61
0
10
20
30
40
50
60
70
80
7-day CO-Synch + CIDR 5-day CO-Synch + CIDR
%
Treatments
n = 17,779 n = 8,245
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Are 2 Injections of PGF Necessary in the 5-day CO-
Synch + CIDR Protocol?
PGF GnRH TAI & GnRH
-5 d 0 8h 72h
CIDR
Interval to 2nd PGF Injection
PGF
PGF x 2 GnRH TAI & GnRH
-5 d 0 72h
CIDR
PGF GnRH TAI & GnRH
-5 d 0 72h
CIDR
(Bridges et al., 2012)
1 x PGF
Co-PGF
8h-PGF
Pregnancy rates
48.0 51.0
55.0
10
20
30
40
50
60
1xPGF Co-PGF 8h-PGF
%
Treatments
(Bridges et al., 2012)
b a,b b
n = 2,465
a,b Percentages differ (P < 0.05)
Answers to field results from a SD herd
438 suckled cows were estrous synchronized using the 7-day CO-Synch + CIDR Protocol.
PGF GnRH TAI & GnRH
CIDR
57
8
18
7
0
10
20
30
40
50
60
TAI First 21 d 21-42 d 42-63 d
Perc
ent
Calving group
n=275
n=85
n=37 n=34
90% Overall pregnancy rate
??
Pregnancy Rates
2.5 5.0
7.5
20.0
37.5
10.0 7.5
5.0 2.5
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
17 18 19 20 21 22 23 24 25
Perc
ent
Days after GnRH
97.5% return to estrus rate!!
Estrus response of cows following the 7-day CO-Synch+CIDR protocol
Average Interval to estrus = 20.9 days
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(Rodgers et al., 2011)
Control
CIDR Natural mating GnRH PGF
TAI + GnRH
TAI
Natural mating
Impact of FTAI on Calving and Weaning
0
10
20
30
40
50
60
70
80
90
100
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Cum
ulat
ive
perc
enta
ge o
f co
ws
calv
ing
Days of calving season
TAI Control
(Rodgers et al., 2011)
Impact of FTAI on Calving and Weaning
18
22
20
15
7 7
3 3
1
4 6
16
25
21
10 9
4 2 1
7
0
5
10
15
20
25
30
1-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 81+ NC
% o
f pre
gnan
t cow
s ca
lvin
g
Days of calving season
TAI Control
* *
*
**
**
Impact of FTAI on Calving and Weaning
(Rodgers et al., 2011)
Treatment
Item Control TAI
No. of cows 615 582
Weaning rate, % 78 84
Weaning weight, lb 387 ± 8a 425 ± 8b
ab Means within row differ (P < 0.01)
Impact of Fixed-Time AI on Calving and Weaning
(Rodgers et al., 2011)
38 lbs
$55
$19
$72
$139
-$6
$36 $30
$47 $49
-$20
$0
$20
$40
$60
$80
$100
$120
$140
$160
1 2 3 4 5 6 7 8 Overall
Net
gai
n or
loss
Location (Rodgers et al., 2012)
Net Gain or Loss Associated with Estrous Synchronization and AI – Location Effects
$25
$47
$57
$64
$0
$10
$20
$30
$40
$50
$60
$70
1:20 1:30 1:40 1:50
Net
gai
n or
loss
Bull:Cow Ratio (Rodgers et al., 2012)
Net Gain or Loss Associated with Estrous Synchronization and AI – Bull to Cow Ratio
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Bull price $3,250
Salvage bull price $75/cwt.
Bull grazing, feed, maintenance $365/year
Interest 7%
Steer calf selling price 550 lb $121/cwt.
Semen $13.00
Reduction in bull/cow ratio 1/17 to 1/34
Model Assumptions
Increased returns $47.09
Decreased Costs $35.23
Decreased Returns $ 0.00
Increased Costs $33.18
Gain $49.14
Summary of Outputs
Change in value based on herd sire costs Bull Value
Item $2,500 $3,500 $4,500
Increased returns (increased value of AI calves)
$58.33 $58.33 $58.33
Decreased costs decreased costs of clean-up bulls)
$29.55 $39.29 $49.04
Decreased returns (Attributed to fewer clean-up bulls included in decreased costs calculation)
$0.00 $0.00 $0.00
Increased costs (additional labor, semen, AI supplies, etc.)
$46.10 $46.10 $46.10
Gain per cow exposed to AI $41.78 $51.52 $61.27
Acknowledgements
People Dr. Carl Dahlen
Dr. Alfredo DiCostanzo Dr. Nicolas DiLorenzo
Dr. Jamie Larson Ms. Kalyn Bischoff
Mrs. Tera Black Mr. Guilherme Marquezini
Mr. Vitor Mercadante Technical staff Support staff Collaborators
Co-authors Beef cattle producers
Funding and Product Support
ABS Global, Inc. Intervet Animal Health IVX/Teva Animal Health
Merial Animal Health Pfizer Animal Health
Select Sires, Inc. Univ. of FL
Univ. of MN USDA-CSREES USDA-TSTAR
Thank You!
Contact Information: Cliff Lamb
University of Florida 3925 HWY 71
Marianna, FL 32446 Tel: 850-394-9124
Email: [email protected]