Study type: Medical/biological study (experimental study)

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

Published in: Anim Reprod Sci 2003; 77 (1-2): 11-20

Aim of study (acc. to author)

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

Background/further details

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.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 60 Hz
Exposure duration: continuous for 16 h/day for up to 2 estrous cycles

Exposure 1

Main characteristics
Frequency 60 Hz
Type
Exposure duration continuous for 16 h/day for up to 2 estrous cycles
Additional info vertical electric field horizontal magnetic field
Exposure setup
Exposure source
Chamber chamber (15 m long, 10 m wide and 3 m high) containing eight wooden box stalls, each holding one cow
Setup 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.
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 10 kV/m - measured - -
magnetic flux density 30 µT - measured - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • before exposure
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

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.

Study character:

Study funded by

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