The Thai Journal of Veterinary Medicine


Semen collection by an electroejaculator was studied in black marsh turtles. High responses were recordedwhen electrical probe was inserted to the depth of 5.9±0.1 cm from the anus or 5.2±0.2 cm from posterior tip of thecarapace. The depth position was approximately the center of the second carapace from the rear. The intensity ofresponses increased with increasing voltage and reached a plateau at 7.0 volts. The depth of the probe inserted toyield highest responses had higher relationship with carapace length when measured against the anus (r= 0.81, p=0.0088) than the posterior end of carapace (r= 0.06, p= 0.8825). Stimulation voltages have been applied as pattern 1: 0.0to 7.0 volts in 20 second, held for 20 second, return to 0.0 and rest 20 sec; pattern 2: 0 to 7.0 volts in 30 sec, held for 30sec, return to 0.0 and repeat stimulus; pattern 3: 0.0 to 7.0 volts in 15 sec, held for 40 sec, return to 0.0 and rest for 5sec. Frequencies of penile protrusion and ejaculation were similar among the 3 patterns of stimulation tested.Frequency of erection, however, was higher in pattern 2 (77.8%) than those in pattern 1 and 3 (38.9 and 50.0 %,respectively, p< 0.05). Time spent to the occurrence of penile protrusion (36.9±5.7, 25.3±4.7 and 33.4±5.6 min forpattern 1, 2 and 3 respectively, p> 0.05), penile erection (42.7±5.2, 31.7±4.5 and 35.0±5.8 min for pattern 1, 2 and 3respectively, p> 0.05) and ejaculation (35.3± 6.4, 34.5±5.0 and 28.1±6.0 min for pattern 1, 2 and 3 respectively, p> 0.05)did not significantly differ. Ejaculations, however, were observed without penile erection. Electrical exposure timesspent to achieve penile protrusion and ejaculation were not different among stimulation patterns studied. Erection, onthe other hand, needed longer exposure time in pattern 3 (20.8±3.1 min) that those in pattern 1 and 2 (15.2±1.9 and16.0±2.2 min, respectively, p< 0.05). In conclusion, electroejaculator can be used to stimulate penile erection andejaculation in black marsh turtles.



First Page


Last Page