P.J. HansenDept. of Animal Sciences University of Florida

Use of embryo transfer to increase pregnancy rates in cattle 

7-8 October 2016, Pozzolengo, Brescia, Italy

Elwyn WillettFirst Successful Embryo Transfer in Cattle

(calf born 19 December 1950)

Top 20 Bulls for Milk IndexAssociazoione Nazionale Allevatori

Frisona Italiana

Vigor daughter

11 of 20 top bulls were produced by ET

Genetic Selection Before Genomics

reliability

Genetic Selection After Genomics

progeny testing

reliability ~ 0.7

reliability ~ 0.25

reliabilityreliability ~ 0.60

Don Bennink – North Florida Holsteins, Bell, Florida

No-Fla Fuelup 33446-ET TY+711 Milk+608 Net Merit

K. Kaniyamattam, J. Block, P. J. Hansen, and A. De Vries, unpublished

Effect of Proportion of Calves Produced by OPU-ETon Breeding Value for Lifetime Net Merit:

Stochastic, Dynamic Dairy Model

0%

100%

Sire

K. Kaniyamattam, J. Block, P. J. Hansen, and A. De Vries, unpublished

Effect of Proportion of Calves Produced by OPU-ETon Profit Per Cow Per Year:

Stochastic, Dynamic Dairy ModelOptimal profit - 40% ET+$1247/cow vs 0% ET

Prospects for Use of Embryo Transfer to Improve Fertility

AI Fert. D 5-7 D 28 D 45 D 75 Term

Num

ber o

f cow

s pr

egna

nt

0

20

40

60

80

100

17%fertilization

failure

37%cleavage-

stagefailure

23%post-

blastocystembryonic

failure

13%late

embryonicfailure

6%Early-to-mid fetalfailure

4%mid-to-late

fetalfailure

Timing of Pregnancy Failure in Lactating Cows(in the absence of heat stress)

ArtificialInsemination

Embryo Transfer

Pregnancy rate at day 25-32

Cows with single ovulation (n=336)

35.6% 40.3%

Cows with > 1 ovulation (n=57)

50.0% 51.7%

Pregnancy loss between day 25-32 and day 60-66

Cows with single ovulation

18.6% 26.2%

Pregnancy rates achieved with AI vs MOETin lactating dairy cows in Wisconsin

Sartori et al., J. Dairy Sci. 86 (Suppl. 1), 238-239 (2003)

Superovulation and IVFaffects the Oocyte and Embryo

Reduced Competence for Development

Are the Optimal Fertility Benefits of ET Being Lost Because ET Procedures Result in Embryos

with Reduced Competence for Development?

Superovulation

FSH

In Vitro Fertilization

In vitro fertilization withconventional, sexedor reverse-sorted semen

• Induce multiple ovulations (superovulation)• Inseminate with conventional semen

Oocyte pickup (OPU) – harvest oocytestransvaginally

Embryo Yield~2-4 embryos/OPU

~26 OPU/yr~52-104 embryos/yr

Embryo Yield~4-6 embryos/procedure

~6 flushes/yr~24-36 embryos/yr

Embryos developin the cow

Embryos developin the lab

Transfer torecipients

Gestation

Study Recipient type

Day of pregnancy diagnosis  In vivo In vitro 

Farin et al., 1995 Heifers 53 d 79% (n=19) 37% (n=19)**

Hasler et al.,  2003  Beef and dairy heifers

50 d 55% (n=199) 37% (n=90)**

Pontes et al., 2007 Bos taurus x B. indicus crossbred heifers

60 d 42% (n=289) 34% (n=910)*

Siqueira et al., 2009

B. taurus x B. indicuscross, non‐lactating cows and heifers

30 d 59% (n=90) 31% (n=87)***

Breukelman et al., 2012

Holstein cows, non‐lactating

98 d 50% (n=115) 43% (n=145)

Differences in pregnancy rate after transfer of fresh embryos produced in vivo or in vitro

Pregnancy rate

Ferraz et al., Theriogenology 86, 1384 (2016)

Pregnancy rates achieved with MOET vs IVFon a large registered Holstein dairy in Florida

WisconsinPr

egna

ncy

rate

(%)

0

10

20

30

40

50

Fresh(n=867)

Fresh(n=7428)

Frozen(n=377)

Frozen(n=1725)

MOET IVF

Progesterone concentrations (mean ± SEM) from Days 1 to 6 in unstimulated recipients (n= 4; open diamonds) and superovulated heifers (n= 9; filled squares).

A. Gad et al. Hum. Reprod. 2011;26:1693-1707

© The Author 2011. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Hierarchical Clustering and Heatmap for Differentially Expressed Genes

Red=High Expression Green= Lower Expression

A. Gad et al. Hum. Reprod. 2011;26:1693-1707

Differentially Expressed GenesDifferentially Expressed Genes >8-fold

454 genes differ in expression-429 greater in MOET-25 lower in MOET

Use of Embryo Transfer to Improve Fertility – Heat Stress

Estrous Behavior

Fertility (Fertilization &Embryonic Growth)

Fetal Growth

Effects of Heat Stresson Reproduction

Jan

19 -

Feb

8 Fe

b 9

- Mar

1M

ar 2

- M

ar 2

2

Mar

23

- Apr

12

Apr 1

3 - M

ay 3

May

4 -

May

24

May

25

- Jun

14

Jun

15 -

Jul 5

Jul 6

- Ju

l 26

Jul 2

7 - A

ug 1

6Au

g 17

- Se

p 6

Sep

7 - S

ep 2

7

Sep

28 -

Oct 1

8

Oct

19 -

Nov

8No

v 9

- Nov

29

Pre

gnan

cy ra

te p

er A

I (%

)

0

10

20

30

40

50

Seasonal Variation in Pregnancy/AI in a Dairy in North Florida(University of Florida Dairy Unit)

Milk

yie

ld (k

g)

7500

8000

8500

9000

9500

10000

10500

19911992

19931994

19951996

19971998

19992000Fi

rst s

ervi

ce p

regn

ancy

rate

, (%

)

15

20

25

30

35

40

45

50

Lopez-Gatius, Theriogenology 60: 203 (2003)

Changes in Pregnancy Rate in Dairy CowsIn Northeastern Spain

Cool season

Warm seasonMilk yield

Seasonal Variation in Conception Rate Per Inseminationin Dairy Cows and Heifers in Florida

Badinga et al., J Dairy Sci. 68:78 (1985)

Body temperature in Holsteins– Wisconsin(Sartori et al., 2002)

Infertility

39.0°C

Use of Embryo Transfer to Improve Fertility – Heat Stress

Heat stress

HS

Control

Delayed Effect of 28‐Day Exposure to Heat Stress on Oocyte Competence to Support Blastocyst Development

in Gir Cows

Torres-Júnior et al., Theriogenology 69:155-166 (2008)

2-cell 4-8 cell Morula 2-cell Day 5 Day 3 Day 4

Dev

elop

men

t to

the

blas

tocy

st s

tage

(%)

0

20

40

6038.5-39oCHeat Shock 1Heat Shock 2

Experiment 1 Experiment 2 Experiment 3

Developmental changes in resistance of bovine embryos to heat shock

Edwards et al., 1997 Krininger et al., 2002 Ju et al., 1999

HS1=41oC 12 h

HS1=43oC 1 hHS1=41oC 6 hHS1=41oC 9 h

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pre

gnan

cy ra

te (%

)

0

10

20

30

40

50

ETAI

** * * * *

T < 22.50C

Vasconcelos et al., Theriogenology 75: 1153 (2011)

Seasonal Variation in Effectiveness of MOET for Improving Fertility in Lactating Holsteins in Brazil

Conception rate of high-producing Holstein cows subjected to AI (n = 19,112) or embryo transfer (ET;

n = 5,364)

Baruselli et al., Theriogenology 76:1583 (2011)

TreatmentPregnancy rate, Day 97 (n=563) Calving rate (n=550)

AI 17.0a 14.6a

ET-Fresh 36.4b 31.2b

ET-Vitrified 25.7c 20.1a

Efficacy of transfer of an in vitro produced embryo for improving fertility in the

summer (Texas)

Stewart et al., J. Dairy Sci. 94: 3437 (2011)

Effectiveness of ET for Improving Pregnancy Ratein the Summer Depends on the Embryo

Cost to produce a female pregnancy in lactating cows

summerRasmussen et al.

An economic analysis of embryo transfer in summer using a simulation model

Albert De Vries• $20 conventional semen used year-round

(normal fertility, 48% heifer calves, cows and heifers)• $60 or $90 female sexed embryos in summer

only in cows (90% heifer calves)

Economic advantage of transfer of fresh, sexed embryos (ET) in the summer in all open cows, depending on cost and relative fertility

* Compared to conception rate of artificial insemination

--ET in summerworks

--Profit dependson embryo quality& cost

Embryo Transfer Improves Fertility in Repeat-Breeder Cows(>3 AI without pregnancy)

Study LocationDefinition of repeat‐breeder Treatment

Number of animals

Pregnancy rate, percent

Son and others, 2007

South Korea 3rd or later breeding

AI at oestrus 27 18.5

Timed AI 13 7.7Timed ET 13 53.8

Block and others, 2010

United States – Florida

> 3rd breeding Timed AI 33 21.1

Timed ET‐fresh

25 60.0

Timed ET‐vitrified

31 29.0

Canu and others, 2010

United Kingdom

4th breeding  AIc 56 30.0

AI + ET 114 52.6

Embryo Transfer Can Improve Fertility--during heat stress--in repeat breeder cows

Improvements in systems for embryo production could result in additional gain in fertility with ET

Peter J. HansenDept. of Animal Sciences

University of FloridaGainesville FL 32611-0910Ph: 352-392-5590 ext 243

hansen@animal.ufl.edu