雌バーラルの血中プロジェステロン濃度の動態と出産時期に基づく繁殖周期 Characterization of the Reproductive Cycle in Female Bharals (Pseudois nayaur) Based on the Changes in Serum Progesterone Concentrations and Parturition Season

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Abstract

雌バーラル(Pseudois nayaur)の血中プロジェステロン(P_4)濃度の年変動を調査し,繁殖季節や発情周期,春機発動などバーラルの繁殖生理を明らかにしようとした.雌バーラル9頭から週1〜2回血液を採取し,ラジオイムノアッセイによりP_4濃度を測定した.血中P_4濃度は,11月または12月(冬)から5〜6月(晩春)までの期間のみ周期的に変動した.この変動に基づく発情周期は,平均24.9±0.5日間であった.血中P_4濃度の上昇開始期前後に,他の雌を追い回す行動や外陰部からの粘液漏出が認められ,これらはバーラルの発情を示す外見的指標になると考えられた.交尾後,妊娠した個体の血中P_4濃度は,周期性を失い,高い値を維持した.調査した37出産例において,出産は4〜9月の間にみられ,5月と6月に全体の約70%が集中していた.出産年月日から推定した受胎時期は10〜4月で,12月が54%と最も多かった.12月は,血中P_4濃度の変動期間の初期にあたることから,ほとんどのバーラルは繁殖季節開始後の早い時期に妊娠し,妊娠しない場合は約25日間の発情周期を繰り返していることが明らかとなった.

The purpose of present study was to determine annual changes in serum progesterone (P_4) concentrations and to clarify basic reproductive characteristics, such as breeding season, estrous cycle, and puberty in female bharals (Pseudois nayaur). Blood was collected from 9 female bharals once or twice weekly for approximately one year. Serum P_4 concentrations were determined by radioim-munoassay. Serum P_4 concentrations showed remarkable and cyclic changes between November/December (winter) and May/June (late spring). The mean estrous cycle was 24.9±0.5 days. Chasing insistently to other females and discharge of mucus from the vulva were observed around the time when the serum P_4 concentrations began to increase. The chasing behavior and discharge of mucus were considered to be external indicators of estrus in female bharals. Serum P_4 concentrations of a pregnant female had non-cyclic changes, and the values remained high. In this study, all 37 deliveries were between April and September, and about 70% of these were concentrated in May and June. The conception month determined on the day of birth was between October and April for all animals, and the most common month was in December (54%). This month corresponded to an early stage of the period when the serum P_4 concentrations changed cyclically. These results indicate that many female bharals become pregnant at the beginning of the breeding seasons and, if they do not become pregnant, the estrous cycle, about 25 days in length, is repeated.

Journal

  • The journal of veterinary medical science

    The journal of veterinary medical science 68(8), 847-851, 2006-08-25

    Japanese Society of Veterinary Science

References:  11

Cited by:  3

Codes

  • NII Article ID (NAID)
    110004814823
  • NII NACSIS-CAT ID (NCID)
    AA10796138
  • Text Lang
    ENG
  • Article Type
    Journal Article
  • ISSN
    09167250
  • NDL Article ID
    8075519
  • NDL Source Classification
    ZR22(科学技術--農林水産--畜産)
  • NDL Call No.
    Z18-350
  • Data Source
    CJP  CJPref  NDL  NII-ELS  IR  JASI 
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