Document Type : Research Paper
Authors
1
Professor, Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran
2
Associate Professor, Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran
3
DVM Graduated from Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran
Abstract
Photoperiod and environmental temperature are two important factors that may influence the reproductive activity of various species. As regards the ambient temperature goes up 50 ˚C in warm months of Khuzestan province, so the aim of the present survey was evaluation of the different season's effect (warm and cold) on testosterone serum concentration in native dogs in Ahvaz district. For this purpose, six adult male dogs, clinically healthy and with age 1.5-2 years old were selected. Blood samples were collected during one year, the middle of each month and in the period between hours 8.30 to 11.30 mornings (72 samples). Testosterone concentration was measured using ELISA technique in serum samples. The obtained results were analyzed by repeated measure ANOVA and Pearson correlation. In this survey, mean±standard error of testosterone serum concentration was detected 4.5±1.8 ng/ml yearly. The minimum and maximum of testosterone concentration were 0.2 and 7.3 ng/ml, respectively. The results showed that the changes of serum testosterone level, were significantly influenced by the sampling month (P<0.0001), so that the lowest levels of testosterone concentration was in May and June (1.7 ng/ml), while the highest level was in January and August (6.7 and 6.8 ng/ml) respectively. The mean testosterone concentration was 4.12±0.25 ng/ml in the warm season and 4.87±0.16 ng/ml in the cold season. The difference was statistically significant between the two seasons (P<0.05). In general, the season variables, have the potential effect on testosterone concentration, that is, the temperature and daylight duration correlated negatively with the testosterone serum concentration (temperature R=- 0.27; P=0.001, daylight duration R=- 0.20; p=0.013), and the humidity level, had a positive significant correlation with testosterone concentration (except August) in the studied dogs (R=0.21; P=0.011). In conclusion, it can be stated that the testosterone concentration is affected by the sampling season.
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