Effects of heat stress on sperm quality of French Bulldogs

This study aimed to evaluate the effects of heat stress (HS) and its duration on semen quality, serum testosterone, pulsatility and resistibility index of the testicular artery of French Bulldogs. Eight male French Bulldogs, 3–7 years old, 12.63 ± 1.8 Kg were adapted and trained for two months. Room temperature was 21 °C. Semen was collected by digital stimulation. The median of four andrological evaluations was T0. Heat was applied to the scrotum using an electrical heat pad at 40 °C for 11 min. Rectal temperature (RT) and scrotum temperature were evaluated using a mercury thermometer and an infrared thermography camera before and after HS. Semen was evaluated immediately (T1) and after seven (T7), 14 (T14), 21 (T21), 28 (T28) and 60 (T60) days after HS. Semen parameters included macroscopic (volume, color and viscosity) and microscopic (sperm motility and vigor, percentage of morphologically normal or defected spermatozoa, sperm concentration and total number of sperm cells) aspects. A pulsed colored doppler ultrasound was performed on the testicular artery at the spermatic cord and epididymis region before and immediately after HS. Serum testosterone was analyzed before, 48 and 96 h after HS. Data was analyzed by ANOVA using SAS. There was a 1.23 °C increase on RT and a 4.98 °C increase on thermograph after HS. Sperm motility decreased at T1 (P