Serum 25(OH) Vitamin D Concentrations in Horses: Effects of Age, Gender, Breed, Skin Colour and Season.
Abstract: The optimal amount of vitamin D required for the proper functioning of the immune system differs from the amount necessary for bone homeostasis. Furthermore, vitamin D metabolism varies among horses. Nevertheless, there is a dearth of information regarding reference values for vitamin D in horses, particularly in the Turkmen breed. The primary objectives of this study were to determine the concentrations of 25-hydroxyvitamin D (25(OH)Vit D) in Turkmen, Thoroughbred and mixed Turkmen × Thoroughbred horses and to explore the effects of various factors on it and its relationship with serum biochemical variables and signalment data. For the measurement of 25(OH)Vit D, 90 healthy horses (min age: 6 months; max age: 10 years) that were stable in the north of Iran (37°17' N, 55°18' E) were selected for clinical examination and complete blood biochemistry analysis. The horses were categorised into different groups based on sex, season (spring, n = 45; autumn, n = 45), breed (Turkmen, Thoroughbred and mixed Turkmen × Thoroughbred), age (< 2 years, 2-8 years and > 8 years) and skin colour. Sampling was performed only once from each horse. In this study, the median serum concentration of 25(OH)Vit D in the sampled horses was 17.42 ng/mL (IQR: 9.82-30.85). The serum 25(OH)Vit D concentration was significantly lower in autumn (median: 15.83 ng/mL and IQR: 8.67-54.68) than in spring (median: 18.02 ng/mL and IQR: 13.77-27.54) and was also lower in Turkmen horses (median: 15.83 ng/mL and IQR: 11.63-23.12) than in mixed breed horses (median: 17.72 ng/mL and IQR: 8.94-51.67) (p ≤ 0.05). According to the results of the present study, the season had a significant effect on the serum 25(OH)Vit D concentration, and this difference was also observed between Turkmen horses and mixed-bred horses (p ≤ 0.05). It is unclear whether the time of sun exposure or vitamin D content of diet causes the seasonal difference of 25(OH)Vit D concentration.
© 2024 The Author(s). Veterinary Medicine and Science published by John Wiley & Sons Ltd.
Publication Date: 2025-01-09 PubMed ID: 39778002PubMed Central: PMC11707397DOI: 10.1002/vms3.70092Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research study analyzes the concentrations of Vitamin D (specifically 25-hydroxyvitamin D) in various breeds of horses and how factors such as age, gender, breed, skin color, and season might impact these levels. The study took 90 healthy horses from three different breeds and found that season, in particular, had a significant effect on Vitamin D concentrations, with lower levels observed during autumn. There were also differences in Vitamin D levels between the breeds, particularly between Turkmen horses and a mixed breed of horses.
Research Purpose and Methodology
- The aim of this study was to assess the concentrations of 25-hydroxyvitamin D (25(OH)Vit D), a form of Vitamin D, in various breeds of horses (Turkmen, Thoroughbred and mixed Turkmen × Thoroughbred), and to investigate the impact of different factors on these levels. These factors included age, gender, breed, skin color, and season. This was done due to the lack of information regarding reference values for vitamin D in horses, specifically in Turkmen breed horses.
- The study sample consisted of 90 healthy horses, ranging in age from 6 months to 10 years, residing in northern Iran. Horses were divided into groups based on sex, season (spring and autumn), breed, age, and skin color. A full biochemistry analysis was done on blood samples taken from each horse.
Research Findings
- The median concentration of 25(OH)Vit D in the horse population was found to be 17.42 ng/mL, with a variable range between 9.82 and 30.85 ng/mL.
- The study found a significant distinction in 25(OH)Vit D concentration between the seasons, with lower levels recorded in autumn than in spring. The median concentration during autumn was 15.83 ng/mL compared to 18.02 ng/mL observed in spring.
- The breed of the horse was another factor that influenced the Vitamin D levels. The Turkmen horses had lower 25(OH)Vit D concentration (median: 15.83 ng/mL) compared to the mixed breed horses (median: 17.72 ng/mL).
Research Conclusions
- The research concluded that season played a crucial role in the horse’s serum 25(OH)Vit D concentration, and differences were also noted between certain horse breeds, particularly between Turkmen and mixed-bred horses.
- It was, however, unclear whether the observed seasonal impacts on 25(OH)Vit D concentration was due to varying sun exposure durations or dietary Vitamin D content. This suggests a need for further research in this area.
Cite This Article
APA
Alemi M, Ahmadi Sheikhsarmast S, Mohri M.
(2025).
Serum 25(OH) Vitamin D Concentrations in Horses: Effects of Age, Gender, Breed, Skin Colour and Season.
Vet Med Sci, 11(1), e70092.
https://doi.org/10.1002/vms3.70092 Publication
Researcher Affiliations
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran.
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran.
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran.
MeSH Terms
- Animals
- Horses / blood
- Horses / physiology
- Seasons
- Vitamin D / blood
- Vitamin D / analogs & derivatives
- Male
- Female
- Skin Pigmentation / physiology
- Age Factors
- Sex Factors
- Iran
- Reference Values
- Aging
Grant Funding
- 3/51695 / Ferdowsi University of Mashhad
Conflict of Interest Statement
The authors declare no conflicts of interest.
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