Download - 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
Increasing submission rates . . .
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
Increasing submission rates . . .
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
Increasing submission rates . . .
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
Increasing submission rates . . .
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
Increasing submission rates . . .
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™
Increasing submission rates . . .
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.
Increasing submission rates . . .
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
Increasing submission rates . . .
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
Increasing submission rates . . .
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)
Increasing submission rates . . .
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
Increasing conception rates . . .
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
Tenhagen et al. (2003)
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
*
Increasing conception rates . . .
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
Tenhagen et al. (2003)
High-Producing CowsHigh-Producing Cows
n = 142
2-yr-olds: >66 lb/day
Older cows: >88 lb/day
*P < 0.05
*
Increasing conception rates . . .
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
Increasing conception rates . . .
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
Increasing conception rates . . .
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
24 to 47 dayspost-AI
38 to 78 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)
Stevenson et al. (2006)
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)
Stevenson et al. (2006)
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