Hormonal control of the ovaries in dairy cattle
I. Comparative results of estrus and
ovulation synchronization methods
G. Gábor, F. Tóth
Dep. of Cattle Breeding Research Institute for Animal Breeding, HHerceghalom, Hungary
ÁTK
HERCEGHALOM
Why is that actual?
• A continuous elevation of the average
milk production
• Herds estrus detection is the main
limitation for the optimal reproductive
performance
• Optimizing reproductive performance by
reproductive management is available
• Pharmaceutical regulation of the estrus
cycle let us synchronizing estrus and
ovulation, regulating follicular waves,
reducing undetected heats, improving AI.
• Aims: Decreasing the parturition
interval and the number of AI per
pregnancy
Regulation of reproduction
Interactive procedure that coordinates and regulates all
reproductive functions
Main elements of the regulation are:
1. Nervous system
•
Fundamental responsibility is translating or transducing
external stimuli into neural signals
2. Endocrine system
•
Pathways are: neural reflex and neuroendocrine reflex.
Simple neural and neuroendocrine reflex
(Senger, 2003)
Reproductive hormones
• Originate
–
–
–
–
–
Hypothalamus
Pituitary
Gonads
Uterus
Placenta
• Cause
–
–
–
–
–
Release of other hormones (releasing hormones)
Stimulate gonads (gonadotropins)
Sexual promotion (steroids)
Pregnancy maintenance
Luteolysis
• Biochemical classification
–
–
–
–
Peptides
Glycoproteins
Steroids
Prostaglandins
The most important hormones
influencing ovarian activity
Hormone
Biochemical Source
classification
Action in female
Effect on
ovary
GnRH
Decapeptide
Hypothalamus Release FSH and LH
Follicular development; ovulation
LH
Glycoprotein
Pituitary
Stimulates ovulation
and P4 secretion
Formation of CL
FSH
Glycoprotein
Pituitary
Follicular development,
E2 synthesis
Development of
follicles
Progesterone
Steroid
CL, placenta
Maintenance of pregnancy
Inhibits GnRH
release
Estradiol
Steroid
Follicle, placenta
Sexual behavior
-
hCG
Glycoprotein
Chorion
ovarian P4 synthesis
-
eCG
Glycoprotein
Chorion
Formation of accessory CL’s
-
PGF2a
Prostaglandin
Endometrium
Destruction of CL
Luteolysis
Inhibin
Glycoprotein
Granulosal cells
Inhibits FSH secretion
Inhibits follicle
development
The estrus cycle of the cow (Senger, 2003)
Methods for inducing estrus and
synchronizing ovulation
• Methods with heat detection
– Progestin application (MGA, PRID, CIDR)
– Deslorelin implant (GnRH agonist)
– Prostaglandin (single or repeated PGf2a im
treatment)
• Timed insemination
– Heatsynch (GnRH - PGf2a – ECP)
– Ovsynch (GnRH - PGf2a – GnRH)
– Provsynch (PGf2a – PGf2a – GnRH - PGf2a –
GnRH) starts 35 days after parturition
The aims of the our experiments
• The usefulness of three different heat induction (single
prostaglandin treatment) and synchronization of
ovulation protocols (Provsynch, Ovsynch) were tested
in two experiments.
• In the first experiment the effectiveness of the different
treatments and the impact on different farms were
compared.
• The objective of the second experiment was to
determine the effect of the Provsynch treatment for (1)
the calving interval, (2) the fertility rate after the first
service and (3) profitability of the Provsynch treatment.
Material and methods
• Experiment 1
– Number of farms: 3
– Animals: H-F crossbred (R3-R4); average milk
production: 8100-8900 kg/cow/year
– Synchronization methods:
» Provsynch (GnRH: Fertagyl, Intervet, PG: Estrumate, Schering)
» Ovsynch: (GnRH: Fertagyl, Intervet, PG: Estrumate, Schering)
» Single PGF2a treatment (Estrumate, Schering)
– Pregnancy detection: PSPB ELISA test (Biopryn), 30-36
days post insemination
Material and methods
• Experiment 2
– One farm, between July 2001 and December 2004
– Animals: H-F crossbred (R2-R4);
– milk production:
•
•
•
•
2001 – 7969 kg
2002 – 8685 kg
2003 – 9300 kg
2004 - 9250 kg
– Synchronization protocols:
» Provsynch (GnRH: Fertagyl, Intervet, PG: Estrumate, Schering)
» Ovsynch: (GnRH: Fertagyl, Intervet, PG: Estrumate, Schering)
» Single PGF2a treatment (Estrumate, Schering), but repeated 14 days later
– Pregnancy detection: ultrasound, 28-42 days post insemination
Material and methods
Treatment Groups
• Prostaglandin F2α
– Cycling cows (P4 serum concentration > 1 ng/ml or CL detected by
ultrasound on ovary) were treated by a single 2 ml (im) injection of
Estrumate. Expected heat occurred generally within 4 days after
treatment
• Ovsynch
– Non-cycling cows (P4 serum concentration < 1 ng/ml or CL not detected
by ultrasound) were put on an Ovsynch regimen. The Ovsynch program
started with an im injection of 150 µg Fertagyl. It was given 7 days before
and again 48 h after an injection of 2 ml Estrumate, im and cows were
inseminated 16–20 h after the second injection of GnRH.
• Provsynch
– The program started at 35 days postpartum (2 ml Estrumate im was
injected twice at a 14-day interval) and followed by the Ovsynch
program, which was initiated 12 days after the second injection of
PGF2α.
• No Treatment
– The animals were inspected for signs of estrus at least three times a day.
The voluntary waiting period from calving to first AI established for this
dairy herd was 60 days.
Results
Table 1: Conception rate (CR) followed the
different treatment
PROVSYNCH
PGF2α
OVSYNCH
Number of AI
721
1229
754
Pregnant cow
278
460
301
Open cow
443
769
453
38.6%
37.4%
39.9%
CR %
Table 2: Pregnancy results (CR %) by treatments
at different farms
PROVSYNCH
PGF2α
OVSYNCH
Farm 1
42.8 %
25.1 %
31.7 %
Farm 2
-
48.1 %
50.4 %
Farm 3
30.7 %
31.5
37.4 %
Table 3: Production and reproduction data between
2002 and 2004
2002
2003
2004
Milk production (kg)
8685
9300
9250
Calving interval (days)
Number of AI per
pregnancy
CR after the first service
(%)
425
410
405
3.01
3.09
2.3
29.8
40.1
44.3
Table 4: Efficiency of the different hormonal
treatments on the CR between 2002 and 2004
No
treatment Provsynch PGF2a Ovsynch
Number of AI
Number of
pregnant cows
*
CR (%)
Mean day
517
430
390
224
192
a,b
37.1
183
b
42.6
120
a
30.8
65
a
29.0
152.5
71.7
155.3
155.5
(conception after calving)
a, b
: Values within rows not sharing a common superscript differ significantly (P < 0.01).
Figure 1: Pregnancy rate of the Provsynch groups
at different times of breeding after calving
(Numbers in parenthesis are number of cows)
Pregnancy rate
60.
050.
040.
030.
7
11
27
57
86
67
46
47
8
27
11
020.
010.
00.
0
66
67
68
69
70
71
72
Days after calving
73
74
75
76
Table 5: Efficiency of the different hormonal
treatments on the CR after the first AI
No
PGF2a Ovsynch Provsynch
treatment
Number of
first AI
Number of
pregnancy
Conception
rate %
Mean day
(calving to conception)
77
76
45
430
21
22
13
183
27.3
28.9
28.9
42.6
77.2
103
94.4
71.4
Table 6: The cost-benefit analysis (profitableness)
of improved fertility results in 2002-2004
Savings (€)
(reduced cost)
13002
2002
25392
2003
31863
2004
70257
Total (€)
*
herd level
Cost
(€)
1627
2136
2575
6338
Profit
*
(€)
11375
23255
29289
63919
Thanks for your attention!
Abnormal (?) CL forms
CL’s with cavities
All they have progesterone production
Reasons:
1. Are they physiological?
CL cyst
2. Metritis
3. NEBAL
4. Metabolic acidosis
Old cyst: how to prepare a differential diagnosis?
January
February
March
April
May
June
July
August
September
October
November
December
Examined (a+b+c)
788
464
602
516
839
884
906
707
587
752
594
393
Involution (c)
183
54
144
119
133
139
158
70
105
171
110
59
Post insemination (b)
395
259
364
305
553
525
490
789
300
421
380
265
Treated (a)
210
151
94
92
153
220
258
-152
182
160
104
69
Pregnant
213
156
177
156
288
226
302
205
162
217
231
124
6
2
6
9
12
3
1
7
2
1
3
4
1
0
0
0
0
0
5
1
0
1
0
0
575
308
438
360
444
639
613
502
325
484
388
269
46
25
34
39
74
47
48
29
44
57
43
30
164
61
73
52
68
99
98
83
105
99
84
45
Pregnant CLcav%
2.8
1.3
3.4
5.8
4.2
1.3
0.3
3.4
1.2
0.5
1.3
3.2
Open CLcav%
8.0
8.1
7.8
10.8
16.7
7.4
7.8
5.8
13.5
11.8
11.1
11.2
Open CLcyst%
28.5
19.8
16.7
14.4
15.3
15.5
16.0
16.5
32.3
20.5
21.6
16.7
Open abnormal
CL%
36.5
27.9
24.4
25.3
32.0
22.8
23.8
22.3
45.8
32.2
32.7
27.9
CLcavity
CLcyst
Open
CLcavity
CLcyst
Pregnant
CLcav%
Open
CLcav%
Open
CLcyst%
Open abnormal
CL%
January
2.8
8.0
28.5
36.5
February
1.3
8.1
19.8
27.9
March
3.4
7.8
16.7
24.4
April
5.8
10.8
14.4
25.3
May
4.2
16.7
15.3
32.0
June
1.3
7.4
15.5
22.8
July
0.3
7.8
16.0
23.8
August
3.4
5.8
16.5
22.3
September
1.2
13.5
32.3
45.8
October
0.5
11.8
20.5
32.2
November
1.3
11.1
21.6
32.7
December
3.2
11.2
16.7
27.9
%
Seasonal changes of luteal abnormalities
Pregnant CLcav%
Open CLcav%
Open CLcyst%
Open abnormal CL%
50.0
45.0
40.0
35.0
30.0
25.0
20.0
15.0
10.0
5.0
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