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.
Publication Date: 2016-02-03 PubMed ID: 26858579PubMed Central: PMC4739144DOI: 10.1294/jes.26.135Google Scholar: Lookup
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- Journal Article
Summary
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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
Researcher Affiliations
- 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.
- Racehorse Clinic, Ritto Training Center, Japan Racing Association, Shiga 520-3085, Japan.
- Equine Science Division, Hidaka Training and Research Center, Japan Racing Association, Hokkaido 057-0171, Japan.
- Department of Clinical Veterinary Sciences, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido 080-8555, Japan.
References
This article includes 28 references
- Aurich C. Reproductive cycles of horses.. Anim Reprod Sci 2011 Apr;124(3-4):220-8.
- Beals KA, Meyer NL. Female athlete triad update.. Clin Sports Med 2007 Jan;26(1):69-89.
- Bonen A, Ling WY, MacIntyre KP, Neil R, McGrail JC, Belcastro AN. Effects of exercise on the serum concentrations of FSH, LH, progesterone, and estradiol.. Eur J Appl Physiol Occup Physiol 1979 Sep;42(1):15-23.
- Brown-Douglas CG, Firth EC, Parkinson TJ, Fennessy PF. Onset of puberty in pasture-raised Thoroughbreds born in southern hemisphere spring and autumn.. Equine Vet J 2004 Sep;36(6):499-504.
- Bullen BA, Skrinar GS, Beitins IZ, von Mering G, Turnbull BA, McArthur JW. Induction of menstrual disorders by strenuous exercise in untrained women.. N Engl J Med 1985 May 23;312(21):1349-53.
- Burrows M, Bird S. The physiology of the highly trained female endurance runner.. Sports Med 2000 Oct;30(4):281-300.
- da Costa RP, Branco V, Pessa P, Silva JR, Ferreira-Dias G. Progesterone receptors and proliferating cell nuclear antigen expression in equine luteal tissue.. Reprod Fertil Dev 2005;17(6):659-66.
- De Souza MJ. Menstrual disturbances in athletes: a focus on luteal phase defects.. Med Sci Sports Exerc 2003 Sep;35(9):1553-63.
- Dhakal P, Hirama A, Nambo Y, Harada T, Sato F, Nagaoka K, Watanabe G, Taya K. Circulating pituitary and gonadal hormones in spring-born Thoroughbred fillies and colts from birth to puberty.. J Reprod Dev 2012;58(5):522-30.
- Dusek T. Influence of high intensity training on menstrual cycle disorders in athletes.. Croat Med J 2001 Feb;42(1):79-82.
- Ginther OJ. Prolonged luteal activity in mares--a semantic quagmire.. Equine Vet J 1990 May;22(3):152-6.
- Ginther O. 1992. Characteristics of the ovulatory season. pp.171–232. In: Reproductive Biology of the Mare Basi and Applied Aspects, 2nd ed. (Ginther, O.J. ed.), Cross Plain, Equiservices, Wisconsin.
- Ginther OJ. Occurrence of anestrus, estrus, diestrus, and ovulation over a 12-month period in mares.. Am J Vet Res 1974 Sep;35(9):1173-9.
- Kanda Y. Investigation of the freely available easy-to-use software 'EZR' for medical statistics.. Bone Marrow Transplant 2013 Mar;48(3):452-8.
- King S, Nequin L, Drake S, Hebner T, Roser J, Evans J. Progesterone levels correlate with impending anestrus in the mare. J. Equine Vet. Sci. 1988;8:109–111.
- King S, Neumann K, Nequin L, Weedman B. Time of onset and ovarian state prior to entry into winter anestrus. J. Equine Vet. Sci. 1993;13:512–515.
- Korosue K, Murase H, Sato F, Ishimaru M, Watanabe G, Harada T, Taya K, Nambo Y. Changes in serum concentrations of prolactin, progestagens, and estradiol-17β and biochemical parameters during peripartum in an agalactic mare. J. Equine Vet. Sci. 2013;33:279–286.
- Loucks AB. Effects of exercise training on the menstrual cycle: existence and mechanisms.. Med Sci Sports Exerc 1990 Jun;22(3):275-80.
- Malina RM, Spirduso WW, Tate C, Baylor AM. Age at menarche and selected menstrual characteristics in athletes at different competitive levels and in different sports.. Med Sci Sports 1978 Fall;10(3):218-22.
- Manore MM, Kam LC, Loucks AB. The female athlete triad: components, nutrition issues, and health consequences.. J Sports Sci 2007;25 Suppl 1:S61-71.
- Nagamine N, Nambo Y, Nagata S, Nagaoka K, Tsunoda N, Taniyama H, Tanaka Y, Tohei A, Watanabe G, Taya K. Inhibin secretion in the mare: localization of inhibin alpha, betaA, and betaB subunits in the ovary.. Biol Reprod 1998 Dec;59(6):1392-8.
- Nattiv A, Loucks AB, Manore MM, Sanborn CF, Sundgot-Borgen J, Warren MP. American College of Sports Medicine position stand. The female athlete triad.. Med Sci Sports Exerc 2007 Oct;39(10):1867-82.
- Palmer E, Driancourt M. Some interactions of season of foaling, photoperiod and ovarian activity in the equine. Livest. Prod. Sci. 1983;10:197–210.
- Stabenfeldt G, Hughes J. Clinical aspects of reproductive endocrinology in the horse. Comp. Con. Edu. Pract. 1987;9:678–684.
- Stabenfeldt GH, Hughes JP, Evans JW, Neely DP. Spontaneous prolongation of luteal activity in the mare.. Equine Vet J 1974 Oct;6(4):158-63.
- Torstveit MK, Sundgot-Borgen J. Participation in leanness sports but not training volume is associated with menstrual dysfunction: a national survey of 1276 elite athletes and controls.. Br J Sports Med 2005 Mar;39(3):141-7.
- Townson DH, Pierson RA, Ginther OJ. Characterization of plasma progesterone concentrations for two distinct luteal morphologies in mares.. Theriogenology 1989 Aug;32(2):197-204.
- Wesson JA, Ginther OJ. Influence of season and age on reproductive activity in pony mares on the basis of a slaughterhouse survey.. J Anim Sci 1981 Jan;52(1):119-29.
Citations
This article has been cited 1 times.- 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.
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