influence of synchronized ovulation and pre- synchronization on pregnancy rates used timed ai in...
TRANSCRIPT
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INFLUENCE OF SYNCHRONIZED OVULATION AND PRE- SYNCHRONIZATIONON PREGNANCY RATES USED TIMEDAI IN LACTATING DAIRY COWS
G. Gabor and F. Toth
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IntroductionDespite increases in milk production, on many farms in Hungary, management (including nutrition, collection and analysis of data, and estrus detection) has often not increased commensurate with increases in herd size. Consequently, there has been a general trend for decreased reproductive performance. Re-breeding of open cows is one of the most effective tools in decreasing of the parturition interval in dairy cows.
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days
Change of parturition interval in controlled herds in Hungary between 1970 - 2002
Munka1
YearsParturition interval (days)
1970399
1971398
1972400
1973399
1974398
1975400
1976403
1977402
1978401
1979400
1980399
1981400
1982397
1983399
1984403
1985400
1986406
1987408
1988408
1989410
1990407
1991413
1992411
1993415
1994416
1995415
1996422
1997419
1998420
1999418
2000424
2001426
2002426
Munka2
Munka3
Munka4
Munka5
Munka6
Munka7
Munka8
Munka9
Munka10
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ObjectivesThe primary objective of the present study was to determine pregnancy rate in lactating dairy cows in Hungary synchronized with the Ovsynch and Provsynch (pre-synchronization and ovulation synchronization) regimens.
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METHODS
AnimalsA field trial was conducted on four Hungarian dairy farms. The cattle were crossbred Holstein-Friesian (R3-R4), with an average of 600 lactating cows. The mean milk productions of the farms were between 7500 and 8500 kg per year.
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All cows were diagnosed with cystic ovarian disease or metritis were excluded from the trial and treated (Figure 1).Furthermore, cows with small, inactive ovaries (ovarian diameter 1.0 to 1.5 cm), were also excluded. The remaining cows were used in the trial and were treated with an Ovsynch or Provsynch protocol. Pregnancy was checked by rectal ultrasonography see Figure 2 - (6 Mhz-linear transducer, Scanner 100 LC Vet, Pie Medical, Maastricht, Nederland) or PSPB test (Biopryn, Biotracking LLC, Moscow, ID, US).
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Luteal cystNormal ovaryFigure 1: Ultrasonic appearance of the cattle ovary
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Figure 2: Ultrasonic appearance of the bovine fetus at different stages of the pregnancy
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PSPB is a novel protein and located in the giant binucleate cells of the trophoblastic ectoderm of the placenta and this indicated that it was either synthesized or sequestered by those cells. Migration of these cells result the appearance of PSPB in the maternal circulation. PSPB is detectable in serum from 24 to 282 (parturition) days of gestation and can be applied reliably in dairy cow herds at 28 to 30 days after breading. Complete clearence of the protein from blood may not occur until 80 to 100 days after parturition. For this reason testing of blood for a new pregnancy following parturition may give false positive tests.An ELISA test (BioPryn by BioTracking LLC) has been developed for the examination of the PSPB in cattle 30 days after AI (at least 90 days after the previous parturition) (Figure 3).
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Figure 3: Biopryn PSPB ELISA test (yellow wells represent pregnant samples)
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OVSYNCH
The Ovsynch protocol consisted of 150 mg GnRH (Fertagyl; Intervet, The Netherlands) on Days 0 and 9 and 500 mg cloprostenol sodium (Estrumate; Schering-Plough, Kenilworth, N.J., US.) on Day 7. Timed AI was carried out 16-24 hours after the 2nd GnRH injection. The Ovsynch was carried out 79 3.8 days (range, 75 to 83) postpartum.
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PROVSYNCHPre-synchronization was achieved with a standard estrous synchronization protocol (PGF2a given twice at a 14-day interval) with the Ovsynch program, initiated 12 days after the second injection of PGF2a. All injections were given im. The mean ( SE) interval from calving to the start of the Provsynch protocol was 35 1.7 d (range, 33 to 37).
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RESULTSTable 1: Pregnancy rates followed the synchronization protocols
Sheet1
Number of AI1742
Correct positive diagnosis772
Correct negative diagnosis638
Fals positive diagnosis292
Fals negative diagnosis40
Sensitivity95.1
Specificity68.6
Positive predicted value72.6
Negative predicted value94.1
Number of AI336
Correct positive diagnosis214
Correct negative diagnosis109
Fals positive diagnosis13
Fals negative diagnosis0
Sensitivity100
Specificity89.1
Positive predicted value94
Negative predicted value100
ProvsynchOvsynch
Farm I43.40%29.40%
Farm II-47.10%
Farm III29.90%35.40%
Farm IV-25.70%
ProvsynchOvsynch
Number of AI332538
Number of pregnant cows127182
Number of open cows206317
Pregnancy rate38.30%33.80%
Sheet2
Sheet3
MBD00152438.xls
Sheet1
termkenyts szma1742
korrekt pozitv772
korrekt negatv638
fals pozitv292
fals negatv40
rzkenysg95.07
negatv elrejelzs94.1
Termkenyts336
Korrekt pozitv316
Korrekt negatv164
Fals pozitv20
Fals negatv0
rzkenysg100
Pozitv elrejelzs94
Negatv elrejelzs100
Sheet2
EmbryonicEmbryonicTotalTotalEmbryonic loss
Pregnantlosslossno. of losslossbetweenMilk kg /Correlation
FarmsNo. of cowsbetweenbetweenbetween%25-36 days36-60 dayscow/year
25-36 days36-60 days25-60 days%
I.1908212915.34.211.18000milk / total loss0.73
II.2515444919.5217.59500milk / loss (25-36 days)-0.36
III.175215179.71.18.67500milk/ implantation0.91
IV.1617172414.94.310.67000
Total777229711914.82.911.98000
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Table 2: Differences of the reproductive efficiency of the different protocols at different farms
Sheet1
Number of AI1742
Correct positive diagnosis772
Correct negative diagnosis638
Fals positive diagnosis292
Fals negative diagnosis40
Sensitivity95.1
Specificity68.6
Positive predicted value72.6
Negative predicted value94.1
Number of AI336
Correct positive diagnosis214
Correct negative diagnosis109
Fals positive diagnosis13
Fals negative diagnosis0
Sensitivity100
Specificity89.1
Positive predicted value94
Negative predicted value100
ProvsynchOvsynch
Farm I43.40%29.40%
Farm II-47.10%
Farm III29.90%35.40%
Farm IV-25.70%
Sheet2
Sheet3
MBD00152438.xls
Sheet1
termkenyts szma1742
korrekt pozitv772
korrekt negatv638
fals pozitv292
fals negatv40
rzkenysg95.07
negatv elrejelzs94.1
Termkenyts336
Korrekt pozitv316
Korrekt negatv164
Fals pozitv20
Fals negatv0
rzkenysg100
Pozitv elrejelzs94
Negatv elrejelzs100
Sheet2
EmbryonicEmbryonicTotalTotalEmbryonic loss
Pregnantlosslossno. of losslossbetweenMilk kg /Correlation
FarmsNo. of cowsbetweenbetweenbetween%25-36 days36-60 dayscow/year
25-36 days36-60 days25-60 days%
I.1908212915.34.211.18000milk / total loss0.73
II.2515444919.5217.59500milk / loss (25-36 days)-0.36
III.175215179.71.18.67500milk/ implantation0.91
IV.1617172414.94.310.67000
Total777229711914.82.911.98000
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DISCUSSIONLarge differences of the reproductive efficiency occurred among the farms. Nutrition and season effects probably caused these differences on the four farms. It can be stated that the reproduction management also influenced the effectivity of the novel treatments as well.
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CONCLUSIONSNew technologies usually help precisely manipulate reproductive function in lactating dairy cows. On the basis of our findings, these regimens would help to reduce anestrus, parturition interval, synchronize return services and enhance embryo survival.