Of course, there are disagreements among dog owners about the optimal time to neuter canines and whether it should even be done at all. To choose the best course of action for both you and your pet, you should always speak with your veterinarian. If you decide to neuter your male Irish Setter, the optimum time to do so is generally between the ages of nine and twelve months, which is after their adolescent stage. If you do it earlier, you risk cutting off the flow of the hormone testosterone, which is essential for the development of bones and muscles. After the female Irish Setter has had her first heat cycle is when it is advised to spay her.