Title: Use of embryo transfer to improve fertility of lactating cows during summer
1Use of embryo transfer to improve fertility of
lactating cows during summer
2Embryo Transfer is Usually A Tool for Genetic
Improvement
Embryo Transfer as a Reproductive Management Tool
Can We Use Embryo Transfer As a Reproductive
Management Tool to Get Cows Pregnant?
Bovine 2-cell embryo
3TAKE HOME MESSAGE Embryo Transfer Can Be
Used to Improve Fertility in Cows Subjected to
Heat Stress and Can Probably be Used to Improve
Fertility in other Cows with Low Fertility
4Changes in Pregnancy Rate in Dairy Cows In
Northeastern Spain
Cool season
Warm season
Milk yield
Lopez-Gatius, Theriogenology 60 203 (2003)
5Effect of Milk Yield on Seasonal Variation in
Pregnancy Rate in Lactating Dairy Cows Florida
South Georgia
100
lt10,000 lb
10,000-20,000 lb
90
gt20,000 lb
80
70
60
90 day non-return rate
50
40
30
20
10
0
J
F
M
A
M
J
J
A
S
O
N
D
Month
6Body temperature Wisconsin (Sartori et al.,
2002)
7Effects of Heat Stress on Reproductive Function
of Dairy Cows that Compromise Fertility
- Follicular development
- Oocyte competence
- Embryonic development
- Progesterone secretion
- Luteal maintenance?
30 days before estrus
Greatest before Day 3
8(No Transcript)
942 d
10Effectiveness of ET vs AI in Summer
29.2
(113)
Pregnancy rate ()
13.5
(524)
AI
MOET fresh
Putney et al., 1989
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12Seasonal Variation in Pregnancy Rate To AI and ET
in Brazil
Rodrigues et al., Proc 15th Int. Congr. Anim.
Reprod., 2396 (2004)
- Study performed on a commercial dairy in
- Descalvado Brazil over three years
- Holstein cows, milk yield averaged 28.4 kg/day
- Two treatments
- AI at natural estrus (n7501)
- Transfer of on vivo embryo (fresh or frozen)
- at 7 days after estrus (n2112)
13T lt 22.50C
14Embryo Transfer as a Reproductive Management Tool
Can We Use Embryo Transfer As a Reproductive
Management Tool to Get Cows Pregnant?
Yes-During Heat Stress
How can we improve the success of ET in summer?
Bovine 2-cell embryo
15Requirements for a Practical System of IVP
Embryo Transfer to Improve Fertility in Summer
Embryos can be produced inexpensively
Pregnancy rates higher than AI --high enough
to recover costs of ET and allow a profit
Effects of heat stress on estrus detection can be
overcome --poor estrus detection limits
number of cows bred Embryos can be stored
frozen --for ease of transfer Embryos give
rise to normal calves
16Abattoir recovery (PD-15 lb)
17Lower pregnancy rates
(19)
a
(320)
a
(1,884)
b
(19)
Pregnancy rate ()
b
In vivo
In vitro
In vivo
In vitro
Adapted from Hasler et al., 1995
Adapted from Farin and Farin, 1995
18Poor freezability of IVP embryos
19MOET vs IVF for Increasing Pregnancy Rate in
Lactating Dairy Cows in Summer
35.4
(48)
24.1
Pregnancy rate ()
18.8
(84)
(48)
IVF
AI
MOET
Frozen
Drost et al., 1999
20110
100
90
80
70
Birth weight (kg)
60
50
40
30
20
16 M 7 F
21Estrus doesnt last long in lactating cows
Dransfield et al., J. Dairy Sci. 811874 (1998)
22Estrus doesnt last long in lactating cows
Walker et al., J. Dairy Sci. 791555 (1996)
23Heat Stress Inhibits Expression of Estrus
Thatcher and Collier, 1986
24Timed Embryo Transfer Bypasses Poor Estrus
Detection in Summer
25Typical protocol for timed embryo transfer with
IVP embryos
26Use of Timed ET with IVP Embryos in Lactating
Recipients Exposed to Heat Stress
synch68 (105/155)
Al-Katanani et al., 2002
27Approaches for Enhancing Pregnancy Rate to IVP ET
Alter the Embryo
Alter the Recipient
Add Growth Factors that Enhance Embryonic
Survival after Transfer
28Preimplantation Embryonic Development and
Insulin-like Growth Factor-1
Improves Development Protects From Elevated Temp
GH System
29Effect of IGF-1 on pregnancy rate in lactating
recipients subjected to heat stress
(28/109)
(23/109)
(28/123)
(23/123)
(17/109)
(9/81)
(17/123)
(9/87)
Pregnancy Rate ()
(8/81)
(8/87)
(6/81)
(6/87)
d 53
d 82
Live calves
Live calves
d 53
d 81
Synchronized recipients
All Recipients
Control IGF-1
30Season x IGF-1 on pregnancy rate
Control IGF-1
60
60
(34/69)
(28/67)
50
50
(23/66)
40
40
(21/74)
(19/70)
Pregnancy Rate ()
(16/73)
(19/70)
30
30
(13/71)
20
20
10
10
0
0
Cool
Hot
Cool
Hot
d 27-32
d 41-49
p lt0.01
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32Sex-sorted semen to eliminate skewed sex ratio
and increase the value of transferred embryos
33Pregnancy rates to AI and embryo transfer
using embryos produced by IVF with sexed
semen and in culture with IGF-1 or GM-CSF
(ongoing)
(data from July August)
Of first 28 calves born to ET, 89 were female
34Requirements for a Practical System of IVP
Embryo Transfer to Improve Fertility in Summer
?
Embryos can be produced inexpensively
Pregnancy rates higher than AI --high enough
to recover costs of ET and allow a profit
Effects of heat stress on estrus detection can be
overcome --poor estrus detection limits
number of cows bred Embryos can be stored
frozen --for ease of transfer Embryos give
rise to normal calves
sexed semen increases the value
?
?but some positive reports
?problems much less
35Embryo Transfer as a Reproductive Management Tool
Can We Use Embryo Transfer As a Reproductive
Management Tool to Get Cows Pregnant?
Yes-During Heat Stress
In Other Populations of Cows????
Bovine 2-cell embryo
36Pregnancy rates achieved with AI vs ET in
lactating dairy cows in Wisconsin Sartori et al.,
Theriogenology 2006 651311-1321
- Data from 243 cows over 365 days (some used gt1x)
- Cows subjected to modified OvSynch and either
- --bred on day of 2nd GnRH
- --received an embryo 7 d after 2nd GnRH
- ---superovulation (78.5 frozen)
- Progesterone used to determine synchronized cows
37Pregnancy rates achieved with AI vs ET in
lactating dairy cows in Wisconsin Sartori et al.,
J. Dairy Sci. 86 (Suppl. 1), 238-239 (2003)
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39Embryo Transfer as a Reproductive Management Tool
Can We Use Embryo Transfer As a Reproductive
Management Tool to Get Cows Pregnant?
Yes-During Heat Stress
No-in Cows with High Fertility
Bovine 2-cell embryo
Yes-in Cows with Low Fertility (needs to be
repeated)
40Acknowledgements
Laboratory Alan Ealy Yaser Al-Katanani Jeremy
Block Barbara Loureiro Luciano Bonilla Rocio
Rivera Jim Moss
Dairies North Florida Holsteins Brooksco Dairy UF
Dairy Research Unit
NRI, IFAFS TSTAR
Collaborators Maarten Drost and Dan Webb, Univ.
Florida Bill Thatcher, Univ. Florida Rick Monson
and Jack Rutledge, Univ. Wisconsin
41hansen_at_animal.ufl.edu