Sterilisation helps to slow down population growth:

In the absence of sterilisation measurements in place homeless animals tend to be neglected, and can die of disease or starvation. Sterilisation becomes crucial for the control and management of free roaming dogs and prevents unwanted litters which further leads to additional homeless and sheltered puppies and dogs.

Sterilisation will suppress undesirable hormone-related behaviours:

Heat cycles in females no longer exist and as a result also eliminate the approach and attraction of unwanted attention by male dogs. Roaming is reduced as male dogs are less likely to wander off an owner’s property if they do not have the hormonal drive to pursue a female in heat. This way they can live happy on a property and are less likely to contract disease or suffer injury due to roaming habits. When male dogs are neutered, they become more protective of their families, and are no longer distracted by temptations of breeding with females. The unwanted aggressive urge is no longer in place, thus lowering their desire to fight with other males. Similarly spayed females become less temperamental and the desire to fight with other females is reduced. Marking in males is also reduced.

Sterilisation helps with the elimination of health risks for the animals themselves:

There are plenty of potentially deadly health conditions and transmissible diseases which dogs can contract and develop due to being intact and mating with other mates that suffer from these conditions and diseases. Examples such as pyometra, TVT, and reproductive cancers can occur. When your dog is sterilized all these risks are eliminated.

Sterilisation will lead to cost-effectiveness:

If your pet is sterilised you will save on the cost of caring for future litters and you will reduce the likelihood of your pet requiring veterinary treatment for injuries occurring when they roam or fight

Sterilisation assists in preventing backyard breeding and reduces the number of purebred and pedigree puppies and dogs ending up in shelters:

If breeders insist on sales contracts that have clauses necessitating sterilisation of the puppy by its owner by a certain date; there will as a result be fewer backyard breeders breeding puppies and dogs. These dogs inevitably land up in shelters or increase the number of stray, homeless and crossbreed puppies and dogs which end up in shelters. It is considered irresponsible and unethical to breed dogs when it is not in the interest of or for the improvement of the breed; and the dogs being bred do not meet or improve upon breeding standards set by the various governing bodies.