It is important to seriously consider desexing your dog. Doing so may help prevent some unsociable activity in your dog, whether barking or escaping and will prevent the trouble of finding homes for unwanted pups.
In Australia, desexing is usually carried out at 6 months of age. Please note that this is something of a convention, and can often be done earlier if necessary for any particular reason. Leaving desexing until 6 months means that there is little room in the timetable for delay, as many dogs can be expected to start exhibiting sexual behaviour at around this age.