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

Animal reproduction science · 2003 · Mixed · Low evidence

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MixedLow evidencePaper 5282

Exposure to 60 Hz electric (10 kV/m) and magnetic (30 microT) fields increased estrous cycle duration (control 19.5±0.4 vs exposed 21.3±0.4 days; P<0.01) and luteal phase duration (control 15.4±0.4 vs exposed 17.2±0.4 days; P<0.01). Progesterone curve area un…

Study snapshot

PublicationAnimal reproduction science · 2003

Study typeother

Reported directionMixed

Evidence ratingLow

Abstract

To study the effects of exposure to extremely low frequency (ELF) electric and magnetic fields (EMF) on the estrous cycle of dairy cows under short-day photoperiod, 16 non-lactating, non-pregnant Holstein cows were exposed to a vertical electric field of 10 kV/m and a horizontal magnetic field of 30 microT for 16 h per day in a cross-over design consisting of two sequences. Each sequence included three periods, and each period corresponded to the duration of one estrous cycle. All animals were maintained under short photoperiod (8 h light/16 h dark) during the trial. Exposure to EMF had an impact on the duration of a complete estrous cycle (P<0.01) and on the duration of the luteal phase (P<0.01). The mean duration of one cycle was 19.5+/-0.4 for the control and 21.3+/-0.4 days for the exposed animals, respectively. The mean duration of the luteal phase was 15.4+/-0.4 days for the control and 17.2+/-0.4 days for the exposed group. The total area under the progesterone (P(4)) curve, the amplitude of the curve or the slope of the P(4) rise at the onset of the luteal phase were not affected by EMF exposure. Results indicate that exposure to EMF may increase the duration of the estrous cycle.

Machine Enhanced Logic

AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeother

Effect directionmixed

Population16 non-lactating, non-pregnant Holstein dairy cows under short-day photoperiod

Sample size16

ExposureELF · 6e-05 MHz · 16 h per day; under 8 h light/16 h dark photoperiod; each period lasted one estrous cycle (cross-over with two sequences, three periods each)

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Outcomes measured

Duration of complete estrous cycle
Duration of luteal phase
Progesterone (P4) curve: total area under curve
Progesterone (P4) curve: amplitude
Progesterone (P4) rise slope at onset of luteal phase

Limitations

Small sample size (n=16).
Details of randomization/blinding and washout between cross-over periods are not described in the abstract.
Study conducted under a specific short-day photoperiod (8 h light/16 h dark), which may limit generalizability.

View raw extracted JSON

{
  "study_type": "other",
  "exposure": {
    "band": "ELF",
    "source": null,
    "frequency_mhz": 6e-05,
    "sar_wkg": null,
    "duration": "16 h per day; under 8 h light/16 h dark photoperiod; each period lasted one estrous cycle (cross-over with two sequences, three periods each)"
  },
  "population": "16 non-lactating, non-pregnant Holstein dairy cows under short-day photoperiod",
  "sample_size": 16,
  "outcomes": [
    "Duration of complete estrous cycle",
    "Duration of luteal phase",
    "Progesterone (P4) curve: total area under curve",
    "Progesterone (P4) curve: amplitude",
    "Progesterone (P4) rise slope at onset of luteal phase"
  ],
  "main_findings": "Exposure to 60 Hz electric (10 kV/m) and magnetic (30 microT) fields increased estrous cycle duration (control 19.5±0.4 vs exposed 21.3±0.4 days; P<0.01) and luteal phase duration (control 15.4±0.4 vs exposed 17.2±0.4 days; P<0.01). Progesterone curve area under the curve, amplitude, and rise slope at luteal onset were not affected.",
  "effect_direction": "mixed",
  "limitations": [
    "Small sample size (n=16).",
    "Details of randomization/blinding and washout between cross-over periods are not described in the abstract.",
    "Study conducted under a specific short-day photoperiod (8 h light/16 h dark), which may limit generalizability."
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "extremely low frequency",
    "ELF",
    "electric field",
    "magnetic field",
    "60 Hz",
    "dairy cows",
    "Holstein",
    "estrous cycle",
    "luteal phase",
    "progesterone",
    "photoperiod",
    "cross-over"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.35,
      "reason": "Study involves controlled exposure to 60 Hz electric and magnetic fields, relevant to ELF exposure contexts."
    }
  ]
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1016/s0378-4320(02)00273-7
PubMed: 12654524

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