New strategies to improve the efficiency of the ovsynch protocol in primiparous dairy cows

• Autorzy: Cirit U , Ak K. , Ileri I.K.
• Języki publikacji: EN

Abstrakty

EN

The aim of this study was to create new strategies to increase the pregnancy rate, in "ovsynch protocol" treatment. Two programs for synchronisation of ovulation and for synchronisation of ovulation and oestrus, similar to the ovsynch, were developed for the use in lactating primiparous dairy cows. Lactating Holstein-Friesian cows were randomly divided into five treatment groups: the GPG group (ovsynch) was treated with GnRH on day 0, PGF (PGF2α) on day 7, and received the second dose of GnRH 48 h later; the groups -7PGPG and - 2PGPG received the same treatment as the GPG group, but were given an additional injection of PGF 7 and 2 d before the start of the GPG treatment; respectively, the PG9PG group received the same treatment as the -2PGPG group, with the modification that the first GnRH injection was given simultaneously with the first PGF on the 2nd d; the GPEG group received the same treatment as the GPG group, but was injected an additional oestradiol propionate (EP) 24 h after the PGF. Plasma progesterone concentrations were determined at the days of the first hormone injection and the last PGF injection. Ovulation rates after the first GnRH and last PGF injections were calculated and presumptive sizes of the follicles on the last PGF injection day were determined in all the cows by rectal palpation. Cows detected to be at oestrus in 72 h after the last PGF injection was inseminated between the 8th and 12th h of their oestrus. Cows not detected to be in oestrus by 72 h after the last PGF received timed artificial insemination (TAI). While the ovulations mostly occurred in the GPG, GPEG, and -7PGPG groups at a period between the 48th and 96th h after the last PGF injection, the ovulations had shifted and occurred between 72 and 120 h, with 66.7% of all ovulations recorded between 72 and 96 h in the -2PGPG group. In the PG9PG group, ovulations took place dispersedly between the 0th and 120th h after the last PGF injection. The pre-synchronisation treatment (-7PGPG) by a PGF injection 7 d prior to the ovsynch protocol did not enhance the ovulation or pregnancy rates. The pre-synchronisation treatment by PGF injected 2 d before the ovsynch protocol, increased the number of cows that ovulated after the first GnRH injection (88.9% vs. 38.9%; P<0.05), produced smaller follicles at the time of the second PGF injection (1.1±0.13 vs. 1.6±0.16 cm; P<0.05) and increased pregnancy rates numerically (72.2% vs. 50.0%; P>0.05). Adding EP to GPG (GPEG), enhanced the expression of oestrus (P<0.05) and increased pregnancy rates slightly (60.0% vs. 50.0%; P>0.05). In conclusion, the -2PGPG and GPEG treatments are potentially new methods for routine synchronisation of ovulation and oestrus and/or ovulation, respectively, in primiparous Holstein-Friesian cows.

Słowa kluczowe

EN

synchronization; cow; ovsynch; primiparous cow; pregnancy rate; new strategy; dairy cow; Holstein-Friesian breed; estradiol

• Wydawca: -
• Czasopismo: Bulletin of the Veterinary Institute in Puławy
• Rocznik: 2007
• Tom: 51
• Numer: 1
• Opis fizyczny: p.47-51,ref.

Twórcy

autor

Cirit U

• Istanbul University, 34320 Avcilar, Istanbul, Turkey

autor

Ak K.

autor

Ileri I.K.

Bibliografia

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