Download ppt - Jeffrey S. Stevenson, Ph.D

Jeffrey S. Stevenson, Ph.D.

Department of Animal Sciences

and Industry

Improving Pregnancy RatesImproving Pregnancy Rates

Ontario Association ofOntario Association ofBovine PractitionersBovine Practitioners

Reproductive SymposiumReproductive Symposium

ObjectiveObjective

Maximize number of pregnancies Maximize number of pregnancies achieved each week!achieved each week!

PR = Submission Rate × Conception RateExample:

Herd #1: PR = 50% SR × 30% CR = 15%15%

Herd #2: PR = 70% SR × 30% CR = 21%21%

Pregnancy Rate FactorsPregnancy Rate Factors

Submission rates• Heat detection• TAI programs for first

services• Frequency of “open”

checks• Resynchrony of repeat

services

Conception rates• Proper handling and placement

of semen• Dry matter intake• Cycling status• Energy balance• Feed supplements

• Use of rbST

• Use of Presynch

• Length of VWP

• Herd health programs

• Sire fertility

Increasing Submission RatesIncreasing Submission Rates

• Heat detection

• TAI programs for first services

• Frequency of “open” checks

• Resynchrony of repeat services

Increasing submission rates . . .

+20 +40

Fertile egg life

OvulationStanding

heat

0

27 h

2040

Secondary heat signs

Normal fertile sperm life

Correct Timing Correct Timing of AIof AI

AI


Source: Hurnik et al. (1975) Appl. Anim. Ethol. 2:55

Standing Activity is a Function of Standing Activity is a Function of the Number of Cows in Estrusthe Number of Cows in Estrus

11

37

53 49

0

10

20

30

40

50

60

No

. of s

tan

din

g e

ven

ts

1 2 3 4+No. of cows in estrus

More mounted cows (90%) are in estrus than mounting ones (79%)

Standing events ranged from 1 to 179

Inclination to mount is stage-of-cycle dependent


Hurnik et al., 1975

Source: Helmer and Britt (1985) JDS 68:1290

Stage of Cycle and Mounting ActivityStage of Cycle and Mounting Activity

Stage of cycle

% of heifers

attempted mounts

% attempted mounts

Luteal Preestrual Estrual Postestrual

48.3 15.4 8.8 27.5

56 203 717 96

5.2 18.9 66.9 9.0

Total 100.0 1072 100.0


Housing and FootingHousing and Footing Maximize the number of nonpregnant

cows housed together to increase heat detection efficiency

During estrus cows prefer to spend 73% of their time on dirt than on concrete

Mounting activity increases 3-15 fold when cows are on dirt

Duration of estrus and standing activity is greater for cows on dirt

Britt et al., 1986


Ovsynch ProtocolOvsynch Protocol

GnRH PGF2

7 days 48 h

GnRH

CL(s)regresses

0 – 24 h

TAI

LHsurge

ovulates

Dominantfollicle

Ovulation

24-34 h

ovulates

Dominantfollicle


GnRH + PGFGnRH + PGF22 + Heat Detection + Heat Detection

(Control) vs. Ovsynch during Summer(Control) vs. Ovsynch during Summer

Item Control Ovsynch

Cows attempted to A.I. 218 207

A.I. submission rate, % 58.7 100

Conception rate, % 32.0 33.3

Pregnancy rate*, % 17.9 33.3

GnRH = Fertagyl™


Cartmill et al., 2001

Transrectal palpation*

Transrectal ultrasound*

Frequency Range Missed AI Range Missed AI

Monthly 35 to 65 1 to 3 28 to 58 1 to 2

Biweekly 35 to 48 1 to 2 28 to 41 1

Weekly 35 to 41 1 to 2 28 to 34 1

Frequency of Pregnancy ChecksFrequency of Pregnancy Checks

*Assumes palpation begins at 35 days and ultrasound at 28 days of pregnancy, respectively.


Pregnancy Check

GnRH

AIPGF

M M W Th

7 days

GnRH

Rebreeding OptionsRebreeding Options

AI

Concentrated heat detection

21-25 days after AI

Applying Ovsynch to Open Cows

Heat Checks


Pregnancy Check

GnRH

AIPGF

M M W Th

7 days

GnRH

Rebreeding OptionsRebreeding Options

AI

Starting Ovsynch 7 days before Preg Checks

Heat ChecksConcentrated heat detection

21-25 days after AI


Pregnancy diagnosis by ultrasonographyCosynch

TAI

0 Day 19 26 28 29

GnRHGnRH

TAIPGF

Resynch before Pregnancy DiagnosisResynch before Pregnancy Diagnosis

Fricke et al., 2003

0 Day 26 33 35 36 0 Day 33 40 42 43

Day 19

Day 26 42%a (n = 240) 34%b (n = 121)

Day 33 33%b (n = 236) 38%b (n = 143)

46%a (n = 235) 23%a (n = 120)

Trt 1st TAI 2nd TAI

(n=711)


20 25 33 40 42 43

GnRH

GnRHTAIPGF

GnRHAIPGF

GnRHGnRH

+ AIPGFPGF PGF

GnRH

W W M M Th

M M W Th

Presynch + Ovsynch

Ovsynch

Days after AI*

Pregnancy diagnosis

M M W Th

Heat checks

All cows Open

cows

14 days 12 days 7 days

7 days

etc.

3 days

7 days

AI Breeding AI Breeding with No Heat with No Heat

DetectionDetection

or

Increasing Conception RatesIncreasing Conception Rates

• Proper handling and placement of semen

• Dry matter intake

• Cycling status

• Energy balance

• Length of VWP

• Herd health programs

• Sire fertility

Handling SemenHandling Semen

Semen handling: Cold shock? Thaw too many straws at one time? Cleanliness of AI equipment Fatigue: Too many cows to AI at one

time? Semen placement

Increasing conception rates . . .

Conception Rates after First AIConception Rates after First AIat Various Postpartum Intervalsat Various Postpartum Intervals

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70 80 90 100 110 >120

Days postpartum

Con

cept

ion

rate

(%

)

Britt, 1975 (8 studies)

0

10

20

30

40

Low Average High

% p

regn

ant a

fter

1st A

I

n=262

73-81 DIM

n=148

73-81 DIM

n=142

73-81 DIM

2-yr-olds

Older cowsMilk yield (lb) at 35 DIM

Tenhagen et al. (2003)

Milk Yield GroupsMilk Yield Groups

<55 55-66 >66

<71 71-88 >88


34.5

14.4

0

10

20

30

40

50

53 to 59 73 to 81

% p

regn

ant a

fter

1st A

I

n = 148


Low-Producing CowsLow-Producing Cows

n = 153

2-yr-olds: <55 lb/day

Older cows: <71 lb/day

Days in Milk at Ovsynch Timed AI*P < 0.05

*


41.4

28.2

0

10

20

30

40

50

73 to 81 94 to 102

% p

regn

ant a

fter

1st A

I

n = 128

Days in Milk at Ovsynch Timed AI


High-Producing CowsHigh-Producing Cows

n = 142

2-yr-olds: >66 lb/day

Older cows: >88 lb/day

*P < 0.05

*


Sire FertilitySire Fertility

Estimated Relative Conception Rate (ERCR)

– Ranking of sires relative to other sires (herds in midwest, east, and south U.S.)

– Based on 70-day non-return rate– Ranges from –5 to +4 for Holsteins and –7 to

+4 for Jerseys (May, 2004)– Go to http://www.drms.org/ Click on “Bull

Fertility Summary”– Generally accurate ranking of sire fertility


http://www.drms.org/

Sire FertilitySire Fertility

AgriTech Analytics (5545 Avenida de los Robles, Visalia, CA 93291; tel: 800-532-0900 or 559-738-5300; fax: 559-738-5321)

– Ranking of sires relative to other sires (herds in western U.S. only). Based on actual pregnancy diagnoses

– Ranges from –9 to +6 for Holsteins (April, 2004). Data for Jerseys are available (5-star system)

Most accurate ranking of actual sire fertility Available for a nominal fee to any dairy producer


AI

4 to 9 dayspost-AI

Pregnancy diagnosis

hCG (3.3 mL of Chorulon)

GnRH (2 mL of Fertagyl)

Control

11 to 16 dayspost-AI



CIDR

AI

AI

AI

Experimental DesignExperimental Design

Percentage of Cows with Percentage of Cows with Induced CL (Exp. 1)Induced CL (Exp. 1)

4.9 4.9

60.0

77.5

0

10

20

30

40

50

60

70

80

90

CON CIDR GnRH hCG

*

*Different from control (P < 0.001)

*

n = 41n = 41 n = 40n = 40

Stevenson et al. (2006)

0

1

2

3

4

5

Control CIDR GnRH hCG

Treatment

Cha

nge

in s

erum

P4

(ng/

mL)

*

n = 190 n = 182 n = 194 n = 187

Change in Concentrations of Change in Concentrations of Progesterone in Serum (Exp. 1)Progesterone in Serum (Exp. 1)

*Different from control (P < 0.001)


Conception Rates after Post-AI Treatments Conception Rates after Post-AI Treatments of P4 (CIDR insert), GnRH, and hCG (Exp. 2)of P4 (CIDR insert), GnRH, and hCG (Exp. 2)

Treatment

Herd Control CIDR GnRH hCG

--------------------- % (no. of cows) --------------------

1 31.7 (41) 50.1† (40) 32.6 (40) 38.7 (38)

2 26.0 (158) 30.8 (158) 28.6 (159) 34.0 (158)

3 26.9 (143) 40.3** (162) 31.3 (153) 37.8* (153)

4 33.8 (206) 23.4* (204) 29.8 (209) 33.7 (209)

5 23.8 (160) 22.3 (147) 20.2 (158) 25.6 (156)

Total1 28.3 (708) 32.7† (711) 28.1 (719) 33.6* (714)†Different from control (P < 0.10; *P < 0.05; **P < 0.01).1A tendency (P = 0.11) for a treatment × herd interaction. Stevenson et al. (2006)

0

10

20

30

40

50

60

4 5 6 7 8 9

Days after AI at Onset of Treatment

Co

nce

ptio

n r

ate

s, %

CON CIDR GnRH hCG

n = 36

n = 216

n = 695

n = 843

n = 1,017

n = 45

Conception Rates by Day ofConception Rates by Day of Treatment (Exp. 2)Treatment (Exp. 2)


The bottom lineThe bottom line ….. is the is the number of pregnancies number of pregnancies produced per unit of time.produced per unit of time.

How does one measure How does one measure the success of the AI-the success of the AI-

breeding program?breeding program?

0

10

20

30

40

50

1 3 5 7 9 12 14 16 18 20 22 24 26

No. of Services No. of Pregnancies

No. of Services and PregnanciesNo. of Services and PregnanciesN

umbe

r

Week of year

WeeklyPreg. Goal

Thank you!

Department of Animal Sciences

and Industry

Ontario Association ofOntario Association ofBovine PractitionersBovine Practitioners

Reproductive SymposiumReproductive Symposium