Is it possible for a neuter to be incomplete?

Question
Hi there, I recently adopted a new bun, named Buddy, as a mate for my existing bun Lola, I'm told Buddy was neutered sometime in May at our city run animal shelter. I cannot find out the exact date of the neuter but he was rescued April 28th so I'm guessing he was neutered in early May. He is still showing what by all appearances is hormonal behaviour during bath tub dates with Lola.

We adopted Buddy in early July. After just 1 week they had a very brief bath tub date since Lola seemed upset and confused by what this new bun was doing here, Lola is very easily stressed even for a bun so I wanted to let her know that Buddy was hopefully going to be her new mate, she knows what bath tub dates means and afterwards was much more relaxed and happy. Buddy did show a stronger hormonal response at that first 5-10 minute date which even if he had been neutered at the end of May would've been 6 weeks since his neuter. None of my other buns have been noticeably hormonal past 6 weeks. Anyways its now been at least 10-12 weeks post neuter and he is still appearing hormonal, though a little less than on their first date. We've also been doing the usual bonding exercises, switching litter boxes, living areas, toys, they eat together separated by a pen, spend a lot of time laying side by side at the pen bars, once a week bath tub dates where I hover over them to ensure nothing happens that might cause a grudge.

Buddy's mounting hasn't lessened in its obsessive type hormonal behaviour much at all since that first date. I had to stop their dates completely last week because Lola was getting upset with him for his intense interest in mounting her that seems to me to go beyond the usual mounting for dominance, Buddy seems changed and transfixed when he starts mounting her. Buddy has seen my vet and she gave him a clean bill of health except for a potential molar spur that is currently less than a 1mm bump. She confirmed he was neutered though they did it in a different fashion than she does them.

What I was wondering is if its possible when Buddy was neutered some tissue was missed and if so could that tissue still be producing hormones? If that is a possibility is there anyway besides surgery to confirm it? Or is it possible for a bun to remain hormonal 10-12 weeks?

Mind you I haven't tried another bath tube date for about 1.5 weeks now so am uncertain if there's been a hormonal change since then. Outside the bath tube dates he doesn't seem very hormonal, my first bun wasn't neutered for about 8 months so I'm familiar with the behaviours of an un-neutered bun.

Thank you for your help,
Rich

Answer
Dear Rich,

It's really unlikely for part of a testicle to be left behind after a neuter.  They are pretty much self-contained capsules, and not friable/easy to break apart.  An adrenal tumor can produce signs like this, but that's not very common.  But it's something you might want to discuss with your vet.  If there is such a tumor, Lupron can help.

But the unfortunate thing is:  some male rabbits are just more "humpy" by nature than others!  This seems to be more true of Holland Lops than in other breeds, but we have a Lionhead/Angora who just canNOT stop humping one of his girlfriends (Saraluna), though he's been neutered for years.  Fortunately, she is one of our "experimental" bunnies in whom we left the ovaries but removed the uterus.  So she LOVES the attention.  But it's a good thing we have her as a "decoy", or Fuzz would drive the spayed girls crazy.  8P

Still, it's only been a few weeks since the neuter.  Gradually, his behavior should dampen and go away.  Sometimes it can take months.  In the meantime, it might be better to find Lola a more staid mate and wait until Buddy is calmed down before allowing him some "blind dates" so he, too, can have a pal.

Hope this helps.

Dana