I never really understand the dynamics of grass and dog urine. I heard female urine is more acidic than male urine. You might take a hint from that and get the soil tested. If the pH is off balance, it can cause nutrient tie up and other problems. Call your local [url=https://extension.oregonstate.edu/locations.php]cooperative extension service[/url] for sampling instructions. Getting a soil test should be done at least every two years so you know if you need to add lime or sulfur to correct for acidic or alkaline soil. If it needs one but doesn't get it, the grass plants cannot manage other nutrients as well as it should, if at all.