Not everyone chooses to have their dogs either spayed or neutered removing female and male reproductive organs respectively. Many owners will leave their dog’s reproductive organs intact. However, dogs that have not had their organs removed may react quite differently to those who have had these organs removed.
Non-neutered males will have a fair amount of testosterone and may constantly struggle for the lead status while a female in heat may not obey commands. Licking may increase and the non-neutered male will often try to mount a female that is in heat. If the dog is then separated from the female they may start breathing rapidly and pacing, there is also a tendency for them to refuse food and even water.
Female dogs that are not spayed will experience menstruation twice a year for about three weeks at a time. During this period females have a tendency to wander off and seek the attention of strange dogs. It is not unusual for a normally passive female to dig under a fence and display their hind parts to every passing male dog.
It is difficult but not impossible during this time to get your dog to comply with your commands. Providing you have retained your alpha or lead status then it is up to you who mates who and when. You will need to be particularly assertive at these times because excited males will only obey up to a point. Even when it is not the mating period a male who has not been neutered will be more inclined to struggle for dominance during the first couple of years. The way to deal with this is to refuse to relinquish your alpha status; there are ways of doing this without using harsh treatment.
You should distract the assertive male with a short rope or ball, this helps to decrease the tension between you as most dogs love to play. You should have control of the ball and hand out or remove the toy. Use the leash, a treat and a firm voice command to obtain compliance as these things help to remind the dog that you are in charge.
Assertive, un-neutered males will have a stronger tendency to pull ahead during leash training. Keep the leash a couple of inches behind you to counter this. When the dog strains give a firm jerk to the right rather than backwards accompanied by a strong command to heel. If the dog walks on your right then you should reverse the directions.
Unless your dog is very small this won't injure them. Dogs have very strong neck muscles. Remember that the goal is to put them off balance and to control rather than to punish.
Dogs that have not been neutered or spayed require even more patience than normal. On the plus side they are less likely to be frightened in certain situations and more willing to take risks. This can be a bonus if you have a certain lifestyle and want to take your dog with you.