Urine spots in the lawn
If you own a dog you're probably familiar with the dead spots in your grass. At sometimes during the year dead spots may be caused by insect damage, however if you especially notice them in the winter and early spring, they're probably caused by your dog.
Dog urine and feces can be a frustrating lawn care problem. Small amounts may produce a green up or fertilizer effect while larger amounts result in lawn burn or dead patches. While most burn spots recover with time, dead areas can be large enough in some cases to require reseeding or sodding.
In the winter time when the weather is bad and your dog just hates to venture too far away from the back door you'll probably notice some definite dead spots in the lawn. This is caused by a combination of repeated urination in the same area that causes a repeated thawing and freezing of the soil and root zone which kills the grass. When grass is actively growing dead lawn spots are caused by too much nitrogen.
There are very few things you can do about this. You certainly don't want to try and modify your dog's diet to reduce these spots. The primary concern from urine damage to lawns is minimizing the nitrogen concentration added to the lawn at any single time. Female dogs, being less likely to urine mark and more likely to squat, are the primary culprits of lawn damage since they will urinate anywhere on a lawn and usually all at once. This results in a single nitrogen dump confined to a small patch of grass. The resulting brown spot often have a green ring around the outside. The nitrogen overload at the center causes the burn, but as the urine dilutes toward the edges, it has a fertilizer effect. This characteristic brown spot / green ring pattern has been called "female dog spot disease" by some horticulturists. As might be expected, lawns most susceptible to nitrogen burns are ones where standard fertilizers are maximized in the lawn.
Trying to change your dog's pH levels to reduce this problem has absolutely no effect. Even though some manufacturers suggest this as a cure all, it will do no good.
A great many dietary modifications for dogs have been tried, often based on home remedies or anecdotal experience. A veterinarian should always be consulted prior to making any dietary modifications, whether they include additions or subtractions from standard nutrient guidelines. As stated earlier, the pH of the urine has little or no effect on the urine damage to the lawn. The addition of acidifying agents, including nutritional supplements like D-I, Methionine (Methioform), Ascorbic Acid (Vitamin C), or fruit juices will have no benefit for this problem and may predispose the dog to an increased incidence of certain bladder stones.
Likewise, alkalinizing agents, including baking soda and potassium citrate can predispose to other types of bladder stones or infections. The addition of any of these supplements has enough potential to cause harm, with limited to no known benefit for the lawn, and are not recommended.
When owners have reported successes, as is sometimes the case on Internet forums, additional liquids added to the dogs intake likely improved the situation because the urine concentration after treatment was diluted. Safer ways to accomplish more dilute urine include feeding canned food, moistening dry food with water prior to feeding and adding some salt to the regular food. One particular home remedy, tomato juice, likely has its primary benefit through both increased salt and water intake. While salt will make the dog drink more and dilute the urine, too much salt intake can cause problems for dogs with existing kidney or heart conditions. Owners should not alter their dog's diet without consulting with their veterinarian.
Dogs with more dilute urine may have to urinate more frequently and need more frequent elimination opportunities. While specific breed differences haven't been noted, smaller dogs produce less urine than larger dogs so are dumping less nitrogen waste. Dogs with bladder infections often demonstrate an urgency to urinate and typically squat several times, leaving small amounts or drops each time. These dogs may be less of a problem for lawns than normal dogs who empty their whole bladder in one sitting. Dog owners who actually note that their dog's urine is no longer causing lawn burn, without having made any changes, should have their dog examined by their veterinarian and a urinalysis performed to make sure there are no medical conditions causing this change.
The other option to consider besides diluting the urine is to reduce the amount of nitrogen waste being dumped in the urine. The average family dog doesn't have the activity level that requires as high a protein level as most commercial maintenance dog foods provide. Although, dog food purchasing often reflects consumer perception that high protein equals better food, in fact moderate to low protein foods are often adequate for all but the most energetic, working and hunting dogs. When examining a food label, protein content must be compared on a dry matter basis and unfortunately, it is not like comparing apples to apples. Dry foods vary in how much moisture they have, so the protein percent listed can't be immediately compared to all other foods. Canned foods will have a much lower protein percent listed than dry foods but also have much higher water content.
The quality of the protein also has an impact since some proteins are highly digestible, meaning less is dumped in the feces and possibly the urine, than other proteins. In general, the premium and super premium pet foods, available from pet stores and veterinarians, will have higher quality protein and more digestible proteins than standard grocery store brands. The higher digestibility translates into smaller fecal size as well. It is probably best to discuss individual pet needs with a veterinarian or nutrition consultant in the practice to determine what is the best fit, based on feasibility, palatability and economics. In many cases, if a dog food is currently providing good, overall nutritional support for the pet, diluting the urine by simply adding water to the food may be the easiest place to start.
Dr. Steve Thompson, DVM - Director
Purdue University Veterinary