Promoting effects of an extended photoperiod treatment on the condition of hair coats and gonadal function in Thoroughbred weanlings.
Abstract: The effects of an extended photoperiod (EP) treatment (14.5 hr light, 9.5 hr dark) on Thoroughbred colts and fillies from December 25 at 7-9 months old to the following May at 12-14 months old on coat condition and gonadal functions were investigated. Coat condition was evaluated in April. The colts and fillies in the EP treatment group changed from winter to summer coats (molting of winter coats), whereas those in the control group did not. To determine the day of first ovulation, the plasma concentrations of progesterone were measured once a month in fillies. The day of first ovulation was advanced in the EP treatment fillies compared with the control fillies. The present study clearly demonstrated that the EP treatment advanced the molting of winter coats and advanced ovulation in fillies, even in weanlings.
Publication Date: 2016-02-03 PubMed ID: 26858581PubMed Central: PMC4739146DOI: 10.1294/jes.26.147Google Scholar: Lookup
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Summary
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The research article explores the influence of an extended light exposure treatment on physical (hair coat condition) and reproductive (gonadal function) conditions of young Thoroughbred horses. The scientists found that the light treatment triggers early shedding of winter coats and advanced first ovulation, indicating its potential use in equine management practices.
Extended Photoperiod Treatment and Its Effects
- The researchers conducted a study on Thoroughbred weanlings, young horses between 7-9 months old, implementing an extended photoperiod (EP) treatment. This treatment involved a light-dark cycle of 14.5 hours of light and 9.5 hours of darkness, starting from December 25th until the following May when the weanlings were 12-14 months old.
- The scientists specifically sought to investigate how the EP treatment affects the horses’ coat condition and gonadal functions.
Impact on Coat Condition
- In April, the researchers examined the horses’ coats to assess effects. They found that the weanlings exposed to the EP treatment exhibited seasonal change in their fur coats, molting from winter to summer coats. The horses in the control group, who were not subjected to EP treatment, did not display the same seasonal coat change.
The Effects on Gonadal Function
- The researchers also examined the reproductive effects of the EP treatment. Specifically, they measured plasma concentrations of progesterone once a month in female young horses (fillies) to determine the day of their first ovulation.
- The results showed an advanced onset of first ovulation in the fillies that were exposed to the EP treatment compared to those in the control group.
Summary of Results and Implications
- The study findings evidently reveal that the EP treatment has significant impacts on young Thoroughbred horses’ physical and reproductive conditions. The treatment initiated early shedding of winter coats and also hastened the first ovulation in fillies.
- These findings have crucial implications in equine management, particularly relating to strategies for shedding and breeding. The use of extended photoperiods can be utilized to manage these processes more effectively.
Cite This Article
APA
Harada T, Nambo Y, Ishimaru M, Sato F, Nagaoka K, Watanabe G, Taya K.
(2016).
Promoting effects of an extended photoperiod treatment on the condition of hair coats and gonadal function in Thoroughbred weanlings.
J Equine Sci, 26(4), 147-150.
https://doi.org/10.1294/jes.26.147 Publication
Researcher Affiliations
- United Graduate School of Veterinary Sciences, Gifu University, Gifu 501-1193, Japan; Laboratory of Veterinary Physiology, Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan.
- United Graduate School of Veterinary Sciences, Gifu University, Gifu 501-1193, Japan; Department of Clinical Veterinary Science, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido 080-8555, Japan.
- Hidaka Training and Research Center, Japan Racing Association, Hokkaido 057-0171, Japan.
- United Graduate School of Veterinary Sciences, Gifu University, Gifu 501-1193, Japan; Hidaka Training and Research Center, Japan Racing Association, Hokkaido 057-0171, Japan.
- United Graduate School of Veterinary Sciences, Gifu University, Gifu 501-1193, Japan; Laboratory of Veterinary Physiology, Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan.
- United Graduate School of Veterinary Sciences, Gifu University, Gifu 501-1193, Japan; Laboratory of Veterinary Physiology, Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan.
- Laboratory of Veterinary Physiology, Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan; Shadai Corporation, Hokkaido 059-1432, Japan.
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