Journal of Reproduction and Development
Online ISSN : 1348-4400
Print ISSN : 0916-8818
ISSN-L : 0916-8818
Volume 44, Issue 5
Displaying 1-4 of 4 articles from this issue
Original Article
  • Masahiko NISHIGAI, Hideo KAMOMAE, Tomomi TANAKA, Yoshihiro KANEDA
    1998 Volume 44 Issue 5 Pages j1-j6
    Published: 1998
    Released on J-STAGE: October 20, 2010
    JOURNAL FREE ACCESS
    The present study was designed to investigate the influence of the period from thawing of frozen bovine compacted morula embryos to non-surgical transfer to recipients and of transportation of the recipients (by truck) to our Embryo Transfer Institute on pregnancy rates. In Experiment 1, excellent or good compacted morula embryos were aspirated into a straw for transfer 16-17 minutes after the initiation of thawing. The embryos were transported to the breeding farm and transferred to the recipients consisting of 96 nulliparous Holstein heifers, 105 Japanese Black cows, and 35 cross breeds. Pregnancy rates were determined at 11-20 (Group 1), 21-30 (Group 2), 31-40 (Group 3), 41-50 (Group 4) and 51-60 minutes (Group 5) after aspiration into the straw. The rates were 50.0% (2/4) to 73.7% (14/19) in Groups 1 through 5 of the Holstein heifers, 50.0% (3/6) to 62.5% (20/32) in Groups 2 through 5 of the Japanese Black cows, and 43.8% (7/16) to 60.0% (6/10) in Groups 2 to 4 of the cross breeds (Japanese Black strain × Holstein strain). No significant differences were found among the groups. In Experiment 2, the Holstein heifer recipients were transported from the breeding farm to our Embryo Transfer Institute by truck which took 1.4-1.6 hours (58-62 kilometers one way). After transportaion the recipients were maintained in stalls for approximately 20 minutes until thawing of the frozen embryos and aspiration of the thawed embryos into the straw were completed. Then procedures similar to those for Experiment 1 were conducted; the embryos were transferred within 10 minutes (Group 6) and 11-20 minutes (Group 7) after the aspiration. The pregnancy rates of the recipients transported by truck, receiving embryo transfer within 30 minutes after aspiration, were determined. They were 69.7% (23/33) and 66.7% (6/9) in Groups 6 and 7, respectively, with no significant difference. These data indicate that pregnancy rates were not affected by the time period between thawing and transfer, if the transfer was completed within 60 minutes after aspiration initiated 16-17 minutes after the commencement of thawing of the compacted morula embryos, or by the 1.5-hour (one way) trucking of recipients.
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  • Eriko UCHIMURA, Shunichi KAMIMURA, Kuniko NAKAJIMA, Katsumi HAMANA
    1998 Volume 44 Issue 5 Pages j7-j11
    Published: 1998
    Released on J-STAGE: October 20, 2010
    JOURNAL FREE ACCESS
    Seasonal variations of sex steroid hormones in follicular fluid, and their follicular morphologies in mares were examined in order to characterize the breeding season in south-western Japan. A total of 194 follicles (>10 mm in diameter) harvested from 28 fattening mares at abattoir in 5 occassions were used for endocrinological and morphological survey. Large follicles >40 mm in diameter and corpora lutea determined with ultrasonography were observed in ovaries collected in March, May and August, whilst they were absent in non-breeding season; January. Ovaries in October showed in-between state; there was a corpus luteum but not large follciles. Follicular development were classified into 4 stages depend on the morphological findings; non-atretic, mild atretic, atretic and heavy-atretic. Most follicles were classified as atretic stages, while non-atretic large follicles >40 mm in diameter were observed in breeding seasons. During the non-breeding season, there were only middle sized non-atretic follicles, 30-40 mm in diameter. Estradiol-17β and progesterone concentrations in follicular fluid decreased as the follicle became atretic. It was concluded that the breeding season was already started by March and was undergone until August, while non-breeding season occurred in October and was utmost in January in south-western Japan. According to morphological survey, although there was neither ovulation nor corpus luteum formation in the ovary, folliculogenesis of middle sized non-atretic follicles indicated the existence of the ovarian follicular developmental activity during the non-breeding season.
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  • Kaori YAMAMOTO, Toshio TSUBOTA, Isao KITA
    1998 Volume 44 Issue 5 Pages j13-j18
    Published: 1998
    Released on J-STAGE: October 20, 2010
    JOURNAL FREE ACCESS
    Sexual behavior of 22 male and 17 female Iapanese black bears, Ursus thibetanus japonicus, in Ani Bear Park was observed for 40 days from June 22 to July 31, 1996. The mating season in this bear park extended from mid-June to early August. Their mating pattern was regarded as promiscuous type. The mating period of females varied from 12 to 35 days widely among animals. The mating period contained estrous and non-estrous period, which occurred irregulaly. Male mating behavior was suspected to accompany female estrus. Total mating days of male bears aged 4-5 years old were less than those of older males. In males over 6 years old, males weighed over 80 kg had more total mating days than smaller males. These suggest that, under captive conditions with high density, some subordinate males, even if they had been matured, were probably unable to have opportunity to breed, due to social hierachy related to the age and body weight of male Japanese black bears.
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Technical Note
  • Ayumi IWAMOTO, Kazuei ITO, Kyoko KAWAHATA, Taichi GOTO, Jutaro TAKAHAS ...
    1998 Volume 44 Issue 5 Pages j19-j24
    Published: 1998
    Released on J-STAGE: October 20, 2010
    JOURNAL FREE ACCESS
    We obtained the medium (IVF-OCM) which cultured bovine ova for 72 hours with TCM-lgg without serum protein after in vitro fertilization, and researched whether Early Pregnancy Factor (EPF)-like substance was able to purify simply from IVF-OCM by using DISC-preparative electrophoresis equipment. EPF activity was detected at a part of fraction purified from IVF-OCM and the protein bands of M. W. 21.5 and 66 KD was observed in its EPF positive fraction. But, all of the other EPF negative fractions had the band of M. W. 66 KD and did not have 21.5 KD band. Therefore, we thought that the band of 21.5 KD was EPF-like substance. Moreover, all of the fraction purified from the cumulus cells culture medium (CM) did not have EPF activities and the band of 21.5 KD. Therefore, EPF-like substance may be secreted from the ovum itself. These results suggests that DISC-preparative electrophoresis is an efficient method for purify EPF-like substance from IVF-OCM.
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