The urine of pets such as cats and dogs contains high levels of nitrogen. If they urinate on lawns the nitrogen overdose can kill the grass.
To prevent the damage caused by pet urine either prevent aniamls gaining access to the lawn or deter them with the use of NO CATS & DOGS animal repellent. Apply to areas where the animals toilet. It can take some time and repeated applications to change the habits of accustomed pets.
Do not over fertilise the lawn with high nitrogen fertilisers as this will mean any additional nitrogen from urine overdoses the lawn.
Pets such as cats and dogs urinating on lawns can cause browning off of the lawn. The high level of nitrogen in the urine of some pets can overdose the grass on nitrogen, particularly if it is a well fertilised lawn.