研究のタイプ: 医学/生物学の研究 (experimental study)

[8時間光周期の間の電界と磁界へばく露した牛の性周期反応] med./bio.

Responses of the estrous cycle in dairy cows exposed to electric and magnetic fields (60 Hz) during 8-h photoperiods.

掲載誌: Anim Reprod Sci 2003; 77 (1-2): 11-20

短日光下で牛の発情周期に対するELF MFばく露の影響を調べために、非妊娠牛を垂直電界10kV/m、水平電界30μTを二つのシーケンスで一日に16時間ばく露させた。各シーケンスに3つの期間を設け、各期間は1発情周期に相当している。試験の間、動物は短日光下(8時間明/16時間暗)で管理された。EMFばく露は完全な発情周期(P<0.01)の期間と黄体フェーズ期間(P<0.01)に対して影響があった。対照群の1周期の平均は19.5±0.4日で、ばく露群は15.4±0.4日であった。プロゲストロン(P4)カーブの全領域、カーブの振幅、黄体フェーズの立上がり時のP4の勾配などにはEMFばく露の影響はなかった。結果として、EMFばく露発情周期を増やす可能性を示した。

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研究目的(著者による)

The effects of exposure of dairy cows to an extremely low frequency electric and magnetic field on the estrous cycle should be investigated.

詳細情報

16 cows, which were synchronized in the starting points of their estrous cycle, were divided into two groups (only 13 cows analyzed; group 1: n=6 and group 2: n=7), each being assigned to a different exposure sequence. Each sequence consisted of three periods and each period corresponded to one estrous cycle. Group 1: sham exposure - exposure - exposure, and group 2: exposure - sham exposure - sham exposure.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 60 Hz
ばく露時間: continuous for 16 h/day for up to 2 estrous cycles

ばく露1

主たる特性
周波数 60 Hz
タイプ
  • electric field
  • magnetic field
ばく露時間 continuous for 16 h/day for up to 2 estrous cycles
Additional information vertical electric field horizontal magnetic field
ばく露装置
ばく露の発生源/構造
チャンバの詳細 chamber (15 m long, 10 m wide and 3 m high) containing eight wooden box stalls, each holding one cow
ばく露装置の詳細 the magnetic field was generated by 14 rectangular coils, 10 m long and 4 m high; the electric field was generated by two plates, 9 m long and 6.5 m wide, that were suspended 0.4 m from the ceiling by synthetic isolators; a short photoperiod (8 h light/16 h dark) was provided during all exposure periods
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
電界強度 10 kV/m - 測定値 - -
磁束密度 30 µT - 測定値 - -

ばく露を受けた生物:

方法 影響評価項目/測定パラメータ/方法

研究対象とした生物試料:
研究対象とした臓器系:
調査の時期:
  • ばく露前
  • ばく露中
  • ばく露後

研究の主なアウトカム(著者による)

The durations of the estrous cycle and luteal phase were found to be slightly but significantly longer under exposure conditions compared to sham exposure conditions.
The authors conclude that exposure of dairy cows to an extremely low frequency electric and magnetic field could increase the duration of the estrous cycle.

研究の種別:

研究助成

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