Guinea Pig breeding boar

Question
I was given a GP boar who is around 1.5 years old. Was told he never  has been able to produce offspring. I have him running with my 3 yr old sow (has had 2 litters in past)
On examining him today I noticed he didn't protrude his penis. my other boars do this when genitally pressed.
Could this be the problem? Is their a known genetic disorder in male GP's?
sorry for the strange question, he is an outstanding boar (pedigree) and would love a litter from him, but he may not have the tools required? (can feel both testes and behaves normally) was over weight when I got him, is currently on a diet.
thankyou

Answer
It's not likely there's a genetic disorder. There may be a testosterone problem that's keeping him from breeding. Of course that's not something we're going to spend the time and money to determine and treat. If he doesn't at least purr and rumblestrut at a sow when he is in the cage with her that could be the problem.

I've had boars that were lazy and didn't show interest in the sows. I found that tossing them in with at least two sows seemed to perk up the passion.

I wouldn't put him on a diet. Unlike rabbits guinea pigs don't need to be kept to a desired weight level.

It's frustrating when you're trying to get them to get down to business and they seem to lack the necessary spunk. Rabbits are spontaneous ovulators and putting the back end of a doe to the front end of a buck will cause her to immediately come into heat and get bred. Cavies just don't follow those rules.  They can be housed together for weeks or months before any action takes place.

If he's just not showing any interest at all you may have to find another boar.