Most of the perceived disadvantages are false. The most quoted of these are that the dog will become fat, lazy and useless as a guard dog. Obesity is probably the most commonly quoted disadvantage of spaying. Obesity is the result of overfeeding and lack of physical activity. The role of female hormones in preventing obesity is poorly understood. By regulating your dog’s diet and caloric intake, you can prevent obesity in spayed or unspayed females. Spaying does not cause a change in personality, guarding instincts, intelligence, playfullness or affection.