There are some methods like rectal stimulation and electric stimulation for semen collection. I have to take samples more than once from a rat, so any suggestion of a method with minimum hazard to rats.
Iam doing massage to the caudal of rat and then after erect penis i use the body of 1 ml syring with small rubber tube moist with lubrecant as artifecial vagina.
cut the syring at mark 4 or 5 and then insert small rubber tube about 0.5 cm with lubrecant into the syring and use the base of needle to block the end of syring body.