Quinn was spayed a few months ago at age 3.
1. She gets PMS BAD! For the couple of weeks before her heats and all the way through, they dogs she lived with would be walking on egg shells around her. You could just see it on her face "WHY DO YOU HAVE TO BE HERE RIGHT NOW?"
I'm a female, I get it. It sucks. It was creating tension between the dogs and it stressed her out.
2. Every heat meant three weeks stuck at home. So not only was she was cranky, she had a lot of pent up energy. Not the making of a very happy Border Collie.
3. She will never be bred. Even if her temperament was perfect (it's far from it) I'm not keen on her structure, even if her structure was great. Her temperament and drives arn't what I'd like to make more of.
However my next dog will be a male, hopefully worthy of being bred one day and it's not worth the stress of 2 entire dogs of opposite sexes.
We've had entire female my entire life, the only other one we desexed was our 11 year old Bull ArabX, multiple pyo scares eventually got us to make the call.
I weighed my decision up for over 3 years with Quinn. Originally the plan was 12 months and I just kept pushing it back. I think for our situation, and for this dog it was the best decision.
That was last August and I am yet to see any change in her drive, temperament, energy or metabolism.