Changes of testosterone serum concentration in two seasons warm and cold in dogs of Ahvaz district

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