Effect of ovarian functions on estrus sychronization and pregnancy rate in brown swiss heifers and non-lactating cows
<b>Aim:</b> In this study, the effect of ovarian functions on estrus synchronization and pregnancy rates in Brown Swiss heifers and non-lactating cows synchronized with a modified ovsynch protocol was investigated.<p> <b>Materials and Methods:</b> The estrous cycle of h...
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| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Selcuk University Press
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| Series: | Eurasian Journal of Veterinary Sciences |
| Subjects: | |
| Online Access: | http://eurasianjvetsci.org/pdf.php3?id=1030 |
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| Summary: | <b>Aim:</b> In this study, the effect of ovarian functions on estrus synchronization
and pregnancy rates in Brown Swiss heifers and
non-lactating cows synchronized with a modified ovsynch protocol
was investigated.<p>
<b>Materials and Methods:</b> The estrous cycle of heifers (n=60) and
cows (n=27) was synchronized with two injections of 150 mcg
d-cloprostenol (PGF<sub>2α</sub>) 14 days apart. Ovulation was induced
with the injection of 50 mcg lesirelin acetate (GnRH) at 48 hour
after the second PGF<sub>2α</sub>, and insemination (AI) was performed
between 16-20 h following the last injection. Corpus luteum and
follicle diameters were measured on days of PGF<sub>2α</sub> and GnRH injection
with ultrasound. Moreover, blood samples were collected
to assess plasma progesterone concentration on days of PGF<sub>2α</sub>
injection and on AI day (day 0) and subsequently on 7, 14 and 21
days. Pregnancy was checked on day 28 after AI.<p>
<b>Results:</b> Synchronization and pregnancy rates were found
87.4% and 36.8%, respectively. The most important factor reducing
the efficacy of protocol during synchronization period
was no luteal function in 6.89% of cows at time of the second
PGF<sub>2α</sub> injection. The affecting negatively on pregnancy rates in
synchronized cows was determined two main factors. 1- Lack of
luteal function on day 7 post-insemination (11.84% of synchronized).
2- Possible early embryonic deaths (11.84% of synchronized).<p>
<b>Conclusions:</b> It was concluded that the ovulation can be synchronized
with modified ovsynch protocol, consisting of two
PGF<sub>2α</sub> and one GnRH injection, and could be achieved to acceptable
pregnancy rate in Brown Swiss heifers and non-lactating
cows. |
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| ISSN: | 1309-6958 2146-1953 |