Strategies to Improve Reproduction during Heat Stress in Dairy Cattle

Dairy Heat Stress RoadshowDairy Heat Stress Roadshow

Todd R. Bilby, Ph.D.Associate Professor and Extension Dairy Specialist

texasdairymatters.org

Heat Wave in 2006 cost ~$1 billion in milk and animals

2 day heat wave in 1999 lost ~$20 million in cattle deaths

and performances losses

July 11 and 12, 1995, ~3700 cattle deaths

New York losses ~$20 million annually

Heat Stress in the U.S.

Annual loss to American Dairy Industry is $897 MILLION!St-Pierre et al., 2003 J. Dairy Sci. E52-E77.

Month J F M A M J J A S O N D

Preg

nanc

y ra

te (%

)

0

10

20

30

40

50

60

70

80

90

100<4536 kg4536-9072 kg>9072 kg

Effect of milk yield on seasonal variation in pregnancy rate in lactating dairy cows:

Florida & Georgia

Al-Katanani et al., 1999

0

10

20

30

40

50

60

70

80

Heat Stress Non - Heat Stress

Fertilization Rate in Lactating Dairy Cows Exposed or Not Exposed to Heat Stress

Ferti

lizati

on R

ate

(%)

Sartori et al., 2010

55

88

Sartori et a., 2002

Heat Stress and Embryo Development

Singlecell

4-cellembryo

Morula EarlyBlastocyst Blastocyst Expanded

Blastocyst

Oviduct Uterus

Day 1 Day 1-2 Day 5 Day 6 Day 7 Day 7-9

Susceptibility to HS

Day 15 – 19 Bovine UterusPGF2

Ovary

CL

Non-Pregnant uterusD17 post-estrus

Pregnant uterusD17 post-estrus

IFN-Embryo

Day

Progesterone and PGF2

Heat Stress:

Decreased weights of embryos on d 17 (Biggers et

al., 1987)

Decreased IFN- by 71 % (Putney et al., 1988b)

Increased endometrial secretion of PGF2α (Putney et al., 1988b)

Up to 40 % of total embryonic losses occur between Days 8 and 17 of pregnancy (Thatcher et al., 1994, 1995). failures in maintenance of CL ?

Embryo Loss for Different THI

01

2

8

12

0

2

4

6

8

10

12

14

<55 55-59 60-64 65-69 >69

preg

nanc

y lo

ss (%

)

Max THI

Adapted from Garcia-Ispierto et al., 2006

Summer vs. Winter:

3.7 times more likely to lose embryo

5.4 times more likely to lose embryo if twins

(Lopez-Gatius et al., 2004)

Strategies to Reduce the Negative Effects of Heat Stress

•Bull Breeding vs. Timed AI•Synchronization and Timed AI•Induction of Accessory CL•Embryo Manipulation and Transfer

NATURAL SERVICE VS. TIMED AI

Semen Quality Before, During and After Heat Stress

Breed Initial Motility Abnormal Spermatozoa

Spermatozoan Concentration

Period % % Initial % % Initial 106 ml-1 % Initial

Holstein 3 wk prior to HS 53 100 9 100 1194 100

1 wk of HS 45 85 13 144 1303 112

1-3 wk after HS 34 64 53 589 537 48

7-9 wk after HS 42 79 29 467 460 39

Johnston et al., 1963

Ambient Temperatures above 27 °C (80 °F) for 6 h per day can reduce semen quality in bulls!

Motile Sperm Before, During and After Heat Stress

Meyerhoeffer et al., 1985

Economic Comparison of NS vs AI (Overton, 2005)

• 60% of the time AI was more profitable than natural service

• Predicted NM$ Gain/Milking Herd = $ 37,480

• In average, use of NS resulted in loss of $ 10.27/cow/year compared with AI

Conclusion: Natural Service vs. AI

• Reduced Genetic Progress and Profitability• Dangerous, cause lameness and injury• Bull Breeding during Heat Stress

– Heat stress decreases sperm concentration, motility, and increases % of abnormal sperm

– Does not return to normal for 2 months!!• IF YOU ARE GOING TO USE BULLS YOU MUST MANAGE

THEM– Rotate, BSE scores, vaccinations, etc..

By-pass negative effects by using A.I.

SYNCHRONIZATION AND TIMED AI

Timed AI vs. Bred on Estrus during Summer

100

1327

18 2317

0

20

40

60

80

100

120

Insemination Rate Conception Rate 120 d PP

TAI

BOE

De la Sota et a., 1998

P < 0.01

P < 0.01

P < 0.05

%

78

59

90 91

0102030405060708090

100

Days Open for Cows Conceiving Interval to First Service

TAI

BOE

Timed AI vs. Bred on Estrus during Summer

Day

s

P < 0.05 P < 0.01

De la Sota et a., 1998

Using TAI to Enhance Summer Cumulative Pregnancy Rates

0

10

20

30

40

50

60

70

1st AI 90-d PP 120-d PP

% P

regn

ant

BOE-1

TAI-1

BOE-2

TAI-2

*

†

*

Aréchiga et al., 1998

*P<.05; † P<.06

INDUCED OVULATION WITH GNRH AT ESTRUS

Daily Progesterone during Spring and Summer in Holstein Cows

Howell et al., 1994

Heat Stress

No Heat Stress

0 2 4 6 8 10 12 14 160

3

6

9

12

0

5000

10000

15000

20000

0

5000

10000

15000

20000

Day of cycleLarge

embryoSmall

embryo

Day 16interferon

Progesterone Concentration and Embryo Production of Interferon-

**

** P<0.01

Prog

este

rone

(ng.

ml-1

)

Inte

rfer

on-t

(uni

ts p

er u

teru

s)

Adapted from Mann et al. (1999)

Effects of GnRH at Estrus on Fertility in Dairy Cows during Summer

52

29 3135

1821

0

10

20

30

40

50

60

Kaim et al., 2003 Ullah et al., 1996 Lopez-Gatius et al., 2006

GnRH

Control

P < 0.05

P < 0.05

Conc

eptio

n Ra

te (%

)

INDUCED ACCESSORY CL AFTER AI

CL Progesterone

Estrus Estrus5 10 15

Hor

mon

e Co

ncen

trati

on

Ovulation

OvulationPGF2a E2

Estrous Cycle

Courtesy of W. W. Thatcher

hCGGnRH

Effect of GnRH Agonist and hCG on Progesterone Concentration in Dairy Heifers

0

5

10

15

20

25

0 2 4 6 8 10 12 14 16

Days of the estrous cycle

Pro

ges

tero

ne

(ng

/mL

)

CON

GnRH

0

5

10

15

20

25

0 2 4 6 8 10 12 14 16

Days of the estrous cycleP

rog

este

ron

e (n

g/m

L)

CON

hCG

GnRH

hCG

11.7

8.5

18.0

9.7

Adapted from Schmitt et al. (1996)

Effect of hCG/GnRH on d 4 or 5 post AI during Summer on Conception Rates

26

38

24

32

24 24 2319

0

5

10

15

20

25

30

35

40

C. Fischer-Tenhagen et al.

(2010)

Karami et al. (2010) Schmitt et al. (1996)

Gandy et al. (2002)

hCG or GnRH

ControlP < 0.01

P < 0.05

Effect of GnRH on d 5 or 11-15 post AI during Summer on Conception Rates

20 19

32

20

35

0

5

10

15

20

25

30

35

40

Franco et al. (2006) Willard et al. (2003)

Control

d 5

d 11 - 15

P < 0.08

Effect of GnRH on d 0 and d 12 post AI during Summer on Conception Rates

42

21

49

31

52

35

0

10

20

30

40

50

60

Ryan et al., (1991) Lopez-Gatius et al. (2006)

Control

d 0

d 0 and 12

b

P < 0.05

P < 0.05

a

b

a

bc

EMBRYO MANIPULATION AND TRANSFER

Heat Stress and Embryo Development

Singlecell

4-cellembryo

Morula EarlyBlastocyst Blastocyst Expanded

Blastocyst

Oviduct Uterus

Day 1 Day 1-2 Day 5 Day 6 Day 7 Day 7-9

Embryo Transfer Susceptibility to HS

05

1015202530354045

05

1015202530354045

IVF

Frozen

Effectiveness of ET vs. AI in SummerPr

egna

ncy

rate

(%)

AI

(524)

(113)

Putney et al., 1989

(84)

(48)

(48)

AIMOET fresh MOET

Drost et al., 1999

Preg

nanc

y ra

te (%

)

05

1015202530354045

13.5%

29.2%

6.7%

17.5%

6.1%

Preg

nanc

y ra

te (%

) Ambrose et al., 1999

TAI

TET

Fresh Frozen

24.1%

35.4%

18.8%

05

1015202530354045

Preg

nanc

y ra

te (%

) Al-Katanani et al., 2002

5.0%

26.7%

7.4%

(46)

(20)

(39)

TAI

TET

Fresh Vitrified

EFFICACY OF EMBRYO TRANSFER IN LACTATING DAIRY COWS DURING SUMMER USING FRESH AND VITRIFIED,

SEXED IN-VITRO PRODUCED EMBRYOS

Stewart et al., 2010

Oocytes collected and graded(Only grades 1 and 2 fertilized)

(21-24 h, 38.5° C + 5 % CO2)Maturation of oocytes

PercollGradient

Fertilization 8h(IVF-TALP)

Expanded Blastocyst d 7

% Cleaved at d 3

Culture(BBH-7)

IVF Embryo Production

Sex-Sorted Semen

Embryo Transfer

EXPERIMENTAL PROCEDURES FOR EMBRYO TRANSFER AND AI

Experimental Design• Two commercial freestall dairies in Central Texas (~3000 milking)

– July to October 2009.

• Primi- and multiparous (n = 722) lactating Holstein dairy cows– Assigned randomly by lactation number, number of previous AI, and

projected 305 d milk yield

• 1 of 3 treatment groups following a synchronized estrus (study d 0)• AI (Control): AI with conventional semen on d 0 (n = 227)• ET-V: Embryo transfer-vitrified on d 7 (n = 279) • ET-F: Embryo transfer-fresh on d 7 (n = 216)

Stewart et al., 2010

Synchronization and Treatment Protocol

Experiment Day -10 -3 -1 0 7 40 ± 7 97±7

AI

ET-F

ET-V

Pregnancy diagnose

Pregnancy diagnose

Pregnancy diagnose

GnRH orEstrus

PGF BS

PGF

Heat Detection

BS

GnRH

GnRH

GnRH

Heat Detection

Heat Detection AI+BSPGF

GnRH or Estrus

GnRH or Estrus

US

VIT+US

FR+US

Ovsynch

Plasma Progesterone Concentration

• Plasma P4 concentration was used to determine conformation of a synchronized estrus

–Synchronized• if P4 was < 1 ng/mL on d 0 and presence of CL on

d 7

Stewart et al., 2010

RESULTS

Percentage of Cows Pregnant at d 40

TRT - P < 0.01 a,b,c - P < 0.01

TRT - P < 0.01 a, b - P < 0.01 x, y– P = 0.10

All Cows Synchronized Cows

Stewart et al., 2010

All Cows

Percentage of Cows Pregnant at d 97

Synchronized Cows

Stewart et al., 2010

Total Births (%) and Live Births (%)

Treatment Total Births (%) Live Births (%)

All cows (n = 550)

Synch cows(n = 460)

All cows (n = 550)

Synch cows(n = 460)

AI 14.6a 17.9a 14.6a 17.9a

ET-V 20.1a 20.9a 17.1a 18.1a

ET-F 31.2b 33.9b 27.5b 29.9b

a, b Values within column with different superscripts differ (P < 0.05)x, y Values within column tend to differ (P ≤ 0.10)

Stewart et al., 2010

Total Heifers (%) and Live Heifers (%)

Treatment Total Heifers (%) Live Heifers (%)

All cows (n = 113)

Synch cows(n = 107)

All cows (n = 113)

Synch cows(n = 107)

AI 50.0a 53.9a 50.0a,x 53.9a,x

ET-V 80.0b 79.0b 72.5y 73.7y

ET-F 88.4b 88.4b 79.1b 79.1b

a, b Values within column with different superscripts differ (P < 0.05)x, y Values within column tend to differ (P ≤ 0.10)

Stewart et al., 2010

Take Home Messages

To Improve Fertility During Summer….

•Aggressive heat detection– Two heat detection aids are better than one

•Robust synchronization and timed AI programs can improve fertility vs. heat detection

– Watch lock up times and compliance

•AI can improve fertility and genetic gain compared to bulls– Bulls can achieve acceptable pregnancy rates but must be aggressively

managed

Take Home Messages

To Improve Fertility During Summer….

•GnRH or hCG on and(or) after AI may improve summer fertility– Results are inconsistent

•Embryo transfer can improve fertility and number of heifers born

– Large scale implementation can be difficult– Need to improve fertility from frozen embryos

Thank You!Todd R. Bilby, Ph.D.

Associate Professor

Dairy Extension Specialist

Texas AgriLife Research and Extension

trbilby@ag.tamu.edu

texasdairymatters.org

This project was supported by Agriculture and Food Research Initiative Competitive Grant no. 2010-85122-20623 from the USDA National Institute of Food and Agriculture.