Seasonal variations of testicular measurements, fresh sperm quality and post-thaw sperm motility in Gurcu goat bucks

Abstract

This study was aimed to determine seasonal variations in testicular measurements and semen characteristics of four Gurcu goat bucks. Data were collected over a whole year. Body weight and morphometric testicular parameters were measured once a month. Semen samples were collected weekly through an artificial vagina, then diluted in a skim milk extender and frozen. Semen volume, sperm concentration, the total number of spermatozoa and the mass activity were evaluated in each extended semen sample. In contrast, sperm progressive motility was assessed prior to the cryopreservation process. In autumn, the testis was larger than in other seasons (P < 0.01). Ejaculate volume increased in winter (P < 0.01), while the total number of spermatozoa increased during the winter even the seasonal effect was not significant (P = 0.24). Post-thaw motility was highest for the semen collected in autumn. In conclusion, although seasonal variation in the characteristics of fresh semen was limited, it may be appropriate to collect semen in autumn, when sperm doses should be cryopreserved for the genetic preservation of this breed.