Dear Bart,

I do not have direct experience with rabbit semen, but I work with canine spermatozoa in ambient temperature during addition of extender before cryopreservation. What the most import think is that semen and extender must have same temperatures (+- 1°C) to avoid cold shock or heat shock.

Best regards

Ondrej

I think that use extender in 36-38oC is a good temperature to use. I worked with rabbit semen during 2000-2003. I'm sending some works that I did, but it hás a problem they are in portuguese. I hope help you. 

Hello Bart,

                   The body temperature of that organism will be apt for its semen.....!!! you will get fantastic results when you handle with same temp as of that organism.....!!!  wish u good luck...!!!

Regards,

Sanketh Dhumal

Dear Bart,

We worked on rabbit semen cryopreservation ten years ago. I agree with Ondrej, it is important to use extenders with similar or same tempeartature with semen. It is a general rule to avoid cold shock causing tail defect (or curling of tail in spermatozoa). In my opinion, you should consider temperature of collection room and time consumption until dilution. I advise you to use benmarie (waterbath) and to keep 30-35C and put your tube containing semen extender and tube containing  semen recently collected. And be sure semen and extender are similar temperature. Then you can start dilution of semen... 

Briefly I advise you to keep semen and extenders in similar temperature. And in my experience the best temperature is 35C for semen dilution if you immediately extend your semen. If there is a time consumption, you can prefer 30C (in rabit semen, gel of ejaculate must be removed prior to dilution and I think it is not time consuming procedure, we used glass bagged or Pasteur pipette in order to remove gel) but you have to consider room temperature or ambient temperature (an other words ejaculate temperature may reduce then you arrange extender temperature and use benmarie to be sure equal temperatures of extender and ejaculate).

My best wishes,

Umut