I have a KC Spaniel. Was born March of 2004. I know the normal cycles for a dog are about 6 months. It was Feb of 2006 before her first cycle and 8 months later before her second. Is that normal for some dogs? I'm, not so patiently waiting for her to come back in. I was wondering if anyone else has experienced the same issue with their dog.
Dogs are a lot like humans, everyone is different. The bigger dogs such as your Spaniel I would look for the first heat cycle around 6 months of age but because she didn't have one doesn't necessarily mean something is wrong. I would think that two years is a little unusual and would have the Vet give her a good once over to make sure everything is ok. I would definitely question breeding her.
I have a couple of female KC spaniels, and their cycles can be different from alot of other breeds. Most of my girls have gone into heat for the first time around a year old, then anywhere from 6 mo-8 mo after that, but sometimes they will "skip" a heat cycle in between. Two years seems too long, though, and should have her thyroid checked ! Good luck !