Seasonal Variations in Scrotal-Testicular Morphometry and Seminal Characteristics of Sirohi Bucks

This study evaluated the effects of seasonal variation on scrotal circumference, testicular biometric indices and fresh seminal characteristics of adult Sirohi bucks. Six healthy bucks were maintained under a semi-intensive system, and body weight, scrotal circumference, testicular length, testicular diameter and testicular volume were recorded at regular intervals across winter, summer, spring and autumn. Semen was collected fortnightly using an artificial vagina and evaluated for ejaculate volume, mass motility, sperm concentration and total sperm output. Body weight did not differ significantly across seasons (p>0.05), with values ranging from 39.060±1.271 kg in winter to 41.440±1.333 kg in autumn. Scrotal circumference differed significantly (p<0.001), with the maximum value in spring (29.970±0.768 cm) and the minimum in winter (25.360±0.367 cm). Testicular length, diameter and volume showed significant seasonal variation, with most maximum values recorded during autumn and minimum values during winter. Ejaculate volume was highest in spring (0.866±0.035 mL; p=0.0001), whereas mass motility was highest in autumn (4.638±0.081; p=0.010). Sperm concentration and total sperm output were highest in winter, reaching 3659.722±72.342 million/mL and 2736.250±125.955 million/ejaculate, respectively. Overall, these findings indicate that season influences testicular indices and seminal parameters in Sirohi bucks, with comparatively favourable semen attributes observed during autumn and winter.