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Journal of equine science2016; 26(4); 135-139; doi: 10.1294/jes.26.135

Seasonal changes in serum progesterone levels in Thoroughbred racehorses in training.

Abstract: The objective of the present study was to verify the seasonal luteal activity of racehorses in training in Japan from March to August. We allocated 102 horses into a luteal activity group and non-luteal activity group. The luteal activity group included horses with serum progesterone levels that were consistently >1 ng/ml and changed by ± 1 ng/ml. In contrast, the progesterone levels of the non-luteal activity group were consistently <1 ng/ml. In late spring (from May 1 to June 30) and summer (from July 1 to August 31), the percentage of horses in the luteal activity group was significantly higher than in early spring (from March 1 to April 30, P<0.01). These findings demonstrate clear seasonal variations in ovarian activity. The present study also suggest that training for a race may not affect ovarian activity in female racehorses.
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Publication Date: 2016-02-03 PubMed ID: 26858579PubMed Central: PMC4739144DOI: 10.1294/jes.26.135Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The researchers sought to explore the variation in ovarian activity in female racehorses during different seasons of the year. The study found that serum progesterone levels, indicating ovarian activity, were significantly higher in late spring and summer compared to early spring.

Study Objectives and Design

  • The aim of this research was to establish seasonal luteal, or ovarian, activity in female racehorses undergoing training in Japan from March through August.
  • In their approach, the researchers divided 102 horses into two categories: horses demonstrating luteal activity, and those without luteal activity. The segregation was based on the concentration of serum progesterone, a hormone produced by the ovaries and typically used as a measure of ovarian activity.

Classification of Luteal Activity

  • The group of horses showing luteal activity consisted of those with serum progesterone levels constantly greater than 1 ng/ml, and with fluctuations within ± 1 ng/ml.
  • Conversely, the non-luteal activity group was determined by horses that consistently had progesterone levels lesser than 1 ng/ml.

Results and Findings

  • This study identified that during late spring (May 1 to June 30) and summer (July 1 to August 31), the proportion of horses in the luteal activity group was noticeably higher than that of horses in early spring (March 1 to April 30).
  • The study clearly revealed seasonal variations in ovarian activity as indicated by progesterone levels, with increased levels in late spring and summer compared to early spring.
  • The increased ovarian activity in the late spring and summer months suggested a physiological adaptation to the seasonal changes occurring in the environment.

Implications of the Study

  • From the findings, the researchers concluded that the training schedule for racehorses does not appear to influence their ovarian activity.
  • This insight is critical for horse trainers and racehorse managers as it suggests that training does not need to be adjusted according to specific times of the year for concern about the impact on ovarian activity in female horses.

Cite This Article

APA
Takahashi Y, Akai M, Murase H, Nambo Y. (2016). Seasonal changes in serum progesterone levels in Thoroughbred racehorses in training. J Equine Sci, 26(4), 135-139. https://doi.org/10.1294/jes.26.135

Publication

Journal of equine science
ISSN: 1340-3516
NlmUniqueID: 9503751
Country: Japan
Language: English
Volume: 26
Issue: 4
Pages: 135-139

Researcher Affiliations

Takahashi, Yuji
  • Racehorse Clinic, Ritto Training Center, Japan Racing Association, Shiga 520-3085, Japan; Present address: Sports Science Division, Equine Research Institute, Japan Racing Association, Tochigi 320-0856, Japan.
Akai, Makoto
  • Racehorse Clinic, Ritto Training Center, Japan Racing Association, Shiga 520-3085, Japan.
Murase, Harutaka
  • Equine Science Division, Hidaka Training and Research Center, Japan Racing Association, Hokkaido 057-0171, Japan.
Nambo, Yasuo
  • Department of Clinical Veterinary Sciences, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido 080-8555, Japan.

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Citations

This article has been cited 1 times.
  1. Takahashi Y, Takahashi T. Seasonal fluctuations in body weight during growth of Thoroughbred racehorses during their athletic career. BMC Vet Res 2017 Aug 18;13(1):257.
    doi: 10.1186/s12917-017-1184-3pubmed: 28821254google scholar: lookup
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