There are many misconceptions about dog urine stains on lawns. They are the result of too much nitrogen applied too quickly to a small area of grass. In just the same way, excessive nitrogen fertiliser can burn or kill grass. Nitrogen in a dog's urine is the result of normal protein breakdown in the digestive system. Modifying or supplementing a dog's diet for the sake of minimising stains on the lawn is not recommended.
Male dogs tend to urinate more frequently and therefore in smaller quantities.
More often that not the lawn can handle this and it soon recovers. Females behave differently, urinating all at once and this tending to leave stains.