Japanese Journal of Veterinary Research;Volume 32, Number 4

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EFFECTS OF LH-RH ANALOGUE ON THE OVULATION RATE AND EMBRYO QUALITY IN HEIFERS SUPEROVULATED WITH PMSG AND PGF_2α

TAKAHASHI, Yoshiyuki;KANAGAWA, Hiroshi

Permalink : http://hdl.handle.net/2115/2312
JaLCDOI : 10.14943/jjvr.32.4.183
KEYWORDS : Superovulation;embryo;PMSG;LH-RH analogue;heifer

Abstract

Eighty-four Holstein-Friesian virgin heifers were superovulated with either 2500 or 3000 IU of PMSG in addition to 30 mg of PGF_2α. The heifers were divided into two groups. Approximately half of them were administered LH-RH analogue twice at 1.5 hour intervals during the superovulatory estrus (treated), and the remaining animals were not treated with LH-RH analogue (control). Nonsurgical embryo recovery was performed 7 or 8 days after estrus. In the control heifers, effects of the dose of PMSG were examined, and it was found that by increasing the dose from 2500 to 3000 IU, a significantly larger number of corpora lutea and total number of eggs were observed (P<0.05). However, the number of good embryos was not increased. These effects of LH-RH analogue were analyzed by comparing the treated and the untreated control heifers following the injection of the same dose of PMSG. The treatment with LH-RH analogue was effective in increasing significantly the number of ovulations and the total number of eggs and good embryos recovered (P<0.05) when the heifers also received 2500 IU of PMSG. The heifers received 3000 IU of PMSG did not show significant responses to LH-RH analogue, but the tendency of a higher percentage of good embryos was recorded.

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