Transcript Slide 1

Ontario Association of
Bovine Practitioners
Reproductive Symposium
Improving Pregnancy Rates
Jeffrey S. Stevenson, Ph.D.
Department of Animal
Sciences and Industry
Objective
Maximize number of pregnancies
achieved each week!
PR = Submission Rate × Conception Rate
Example:
Herd #1: PR = 50% SR × 30% CR = 15%
Herd #2: PR = 70% SR × 30% CR = 21%
Pregnancy 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 rates . . .
Increasing Submission Rates
•
•
•
•
Heat detection
TAI programs for first services
Frequency of “open” checks
Resynchrony of repeat services
Increasing submission rates . . .
27 h
Ovulation
Standing
Fertile
heat
egg life
Secondary
heat signs
40
20
0
+20
+40
AI
Correct Timing
of AI
Normal fertile
sperm life
Increasing submission rates . . .
No. of standing events
Standing Activity is a Function of
the Number of Cows in Estrus
60
53
50
49
37
40
30
20
11
10
0
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
Source: Hurnik et al. (1975) Appl.
Anim. Ethol. 2:55
Hurnik et al., 1975
Increasing submission rates . . .
Stage of Cycle and Mounting Activity
Stage of cycle
% of
heifers
Luteal
Preestrual
Estrual
Postestrual
Total
48.3
15.4
8.8
27.5
100.0
 attempted % attempted
mounts
mounts
56
203
717
96
1072
Source: Helmer and Britt (1985)
JDS 68:1290
5.2
18.9
66.9
9.0
100.0
Increasing submission rates . . .
Housing 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 Protocol
Ovulation
GnRH
PGF2
7 days
48 h
GnRH
TAI
0 – 24 h
24-34 h
Dominant
follicle
ovulates
CL(s)
regresses
LH
surge
Dominant
follicle
ovulates
Increasing submission rates . . .
GnRH + PGF2 + Heat Detection
(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
Increasing submission rates . . .
Frequency of Pregnancy Checks
Transrectal
palpation*
Frequency
Transrectal
ultrasound*
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
*Assumes palpation begins at 35 days and ultrasound at 28 days of
pregnancy, respectively.
Increasing submission rates . . .
Rebreeding Options
Applying Ovsynch
to Open Cows
Pregnancy
Check
GnRH
PGF
AI
GnRH
AI
7 days
M
Concentrated
heat detection
21-25 days
after AI
M
W Th
Heat Checks
Increasing submission rates . . .
Rebreeding Options
Starting Ovsynch 7 days
before Preg Checks
GnRH
AI
Pregnancy
Check
GnRH
PGF
AI
7 days
M
Concentrated
heat detection
21-25 days
after AI
M
W Th
Heat Checks
Increasing submission rates . . .
Resynch before Pregnancy Diagnosis
Pregnancy diagnosis by ultrasonography
Cosynch
TAI
0
0
0
GnRH
(n=711)
Trt
Day 19
Day 26
Day 33
1st TAI
GnRH
PGF
TAI
26
33
40
28 29
35 36
42 43
2nd TAI
Day 19
46%a (n = 235)
23%a (n = 120)
Day 26
42%a (n = 240)
34%b (n = 121)
Day 33
33%b (n = 236)
38%b (n = 143) Fricke et al., 2003
PGF
PGF
14 days
W
M
AI Breeding
with No Heat
Detection
25
3 days
M
Presynch +
Ovsynch
Th
GnRH
PGF
AI
GnRH
or
7 days
M
Ovsynch
M
W Th
Pregnancy diagnosis
All
cows
20
7 days
12 days
W
Heat
checks
PGF
GnRH
GnRH
+ AI
GnRH
GnRH
PGF
TAI
Open
cows
7 days
etc.
33
40 42 43
M
M
W Th
Days after AI*
Increasing Conception Rates
• Proper handling
and placement of
semen
• Dry matter intake
• Cycling status
• Energy balance
• Length of VWP
• Herd health
programs
• Sire fertility
Increasing conception rates . . .
Handling 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
Conception Rates after First AI
at Various Postpartum Intervals
Conception rate (%)
80
70
60
50
40
30
20
10
0
0
10
Britt, 1975 (8 studies)
20
30
40
50
60
70
80
Days postpartum
90 100 110 >120
Increasing conception rates . . .
Milk Yield Groups
% pregnant after 1st AI
40
30
20
10
n=148
n=262
n=142
73-81 DIM
73-81 DIM
73-81 DIM
Low
<55
Average
55-66
High
>66
0
2-yr-olds
Older cows
<71
Tenhagen et al. (2003)
71-88
>88
Milk yield (lb) at 35 DIM
Increasing conception rates . . .
Low-Producing Cows
% pregnant after 1st AI
50
2-yr-olds: <55 lb/day
40
Older cows: <71 lb/day
34.5 *
30
20
14.4
10
n = 153
n = 148
53 to 59
73 to 81
0
*P < 0.05
Days in Milk at Ovsynch Timed AI
Tenhagen et al. (2003)
Increasing conception rates . . .
High-Producing Cows
% pregnant after 1st AI
50
2-yr-olds: >66 lb/day
40
Older cows: >88 lb/day
30
28.2
41.4 *
20
10
n = 142
n = 128
73 to 81
94 to 102
0
Days in Milk at Ovsynch Timed AI
Tenhagen et al. (2003)
*P < 0.05
Increasing conception rates . . .
Sire 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 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
Experimental Design
CIDR
AI hCG (3.3 mL of Chorulon)
AI GnRH (2 mL of Fertagyl) Pregnancy diagnosis
AI
Control
4 to 9 days
post-AI
11 to 16 days
post-AI
24 to 47 days
post-AI
38 to 78 days
post-AI
Percentage of Cows with
Induced CL (Exp. 1)
90
77.5 *
80
70
60.0 *
60
50
40
30
20
10
n = 41
n = 41
4.9
4.9
CON
CIDR
n = 40
n = 40
GnRH
hCG
0
Stevenson et al. (2006)
*Different from control (P < 0.001)
Change in serum P4 (ng/mL)
Change in Concentrations of
Progesterone in Serum (Exp. 1)
5
*Different from control (P < 0.001)
*
4
3
2
1
n = 190
n = 182
n = 194
n = 187
Control
CIDR
GnRH
hCG
0
Stevenson et al. (2006)
Treatment
Conception Rates after Post-AI Treatments
of P4 (CIDR insert), GnRH, and hCG (Exp. 2)
Herd
Control
Treatment
CIDR
GnRH
hCG
--------------------- % (no. of cows) -------------------1
31.7 (41)
2
3
4
50.1† (40)
32.6 (40)
38.7 (38)
26.0 (158) 30.8 (158)
26.9 (143) 40.3** (162)
33.8 (206) 23.4* (204)
28.6 (159)
31.3 (153)
29.8 (209)
34.0 (158)
37.8* (153)
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)
Conception rates, %
60
Conception Rates by Day of
Treatment (Exp. 2)
CON
50
CIDR
GnRH
hCG
40
30
20
n = 216
10
n = 36
n = 843
n = 45
n = 1,017
n = 695
0
4
Stevenson et al. (2006)
5
6
7
8
Days after AI at Onset of Treatment
9
How does one measure
the success of the AIbreeding program?
The bottom line ….. is the
number of pregnancies
produced per unit of time.
No. of Services and Pregnancies
No. of Services
No. of Pregnancies
50
Number
40
30
Weekly
Preg.
Goal
20
10
0
1
3
5
7
9
12 14 16 18 20 22 24 26
Week of year
Ontario Association of
Bovine Practitioners
Reproductive Symposium
Thank you!
Department of Animal
Sciences and Industry