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"DOG-ON-IT" LAWN PROBLEMS
"Dogs Damage
Lawns," would not be an attention-grabbing headline, because
it’s so commonplace. So common in fact that a series of urban
myths has arisen over what causes the damage, i.e., female dog urine
is more acidic and therefore damaging than male, and what homeowners
can do to avoid the problem such as, adding tomato juice to the
animal’s diet or baking soda to its water.
In order to
address the matter in an informed and scientific manner, the Turf
Resource Center, a international, non-profit group headquartered
in suburban Chicago, invited Dr. Steve Thompson to prepare the following
in-depth article on the subject. The information is reprinted here
with permission of the Center.
Dog urine and
feces can often be a frustrating problem related to lawn care. Small
amounts may produce a green up or fertilizer effect while larger
amounts often result in lawn burn or dead patches. While most burn
spots will recover with time and regrowth, dead areas can be large
enough in some cases to require reseeding or sodding. For homeowners
who are also dog lovers, this can present a dilemma, particularly
when one family member prefers the dog and another prefers a well-manicured
lawn. An understanding of the interaction between dogs and the lawn
can keep the yard (and family) at peace, not in pieces.
Understanding
the causes
The fundamental
problem with the presence of urine or feces on the lawn is related
to the nitrogen content and concentration of these waste products.
Urine, when produced as a waste product in animals, primarily removes
excess nitrogen from the body via the kidneys. Nitrogen waste products
are the result of protein breakdown through normal bodily processes.
Carnivores, including cats and dogs, have a significant protein
requirement, and urine volume/production varies due to size and
metabolism. Urine is a more serious problem for lawns because it
is applied all at once as a liquid fertilizer, whereas feces slowly
releases the waste products over time. Since stools are usually
solid, owners have the option of frequent manual removal. With more
time for the nitrogen waste to dissolve into the lawn, stools that
are frequently removed damage lawns less than urine.
Young dogs of
both sexes frequently squat to urinate. Leg lifting is often learned
by male dogs around a year of age; castration or neutering does
not seen to affect nature’s timetable related to this behavior
development. While most male dogs will hike their leg and mark once
they are over a year of age, a few will continue to squat when urinating,
which is more common in female dogs. Female dogs may also mark although
less commonly than male dogs. Once dogs begin urine marking, they
often utilize many and numerous scent posts resulting in numerous,
small volume urinations rather than large volume puddles. Grass
can handle small volume nitrogen bursts easier than fertilizer overload.
Unfortunately, the young bush, shrub, vine or tree sprout that becomes
a marking post may have nitrogen (fertilizer) overload with repeated
marking and may die if continually "marked."
The primary
concern in addressing 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 brown spot that results
will often have a green ring around the outside. The nitrogen overload
at the center causes the burn, but as the urine is diluted toward
the periphery, 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 are most susceptible
to nitrogen burns when standard fertilizers are maximized in the
lawn. Homeowners making the extra effort to have a green lawn may
be quite discouraged by their neighbor’s dog damage or their
own housepet’s potty residue.
Speculation
on the actual cause of the lawn burn has resulted in numerous theories
on what else in the urine may be contributing to the damage. Dr.
A.W. Allard, a Colorado veterinarian, examined numerous variations
in dog urine and the effects on several common lawn grasses1. His
results support the fact that volume of urine (nitrogen content)
and urine concentration had the most deleterious effects on lawns.
The pH of the urine did not have any variable effect nor did common
additives designed to alter the urine pH. Of the four grasses tested,
Festuca sp. var. Kentucky 31 (fescue) and Lolium perrene (perennial
ryegrass) were the most resistant to urine effects. In fact, the
urine routinely produced a fertilizer effect on these grasses at
diluted concentrations. Poa pratensis (Kentucky bluegrass) and Cynodon
sp. var. Fairway (bermudagrass) were very sensitive to any urine
concentration and severe burns resulted, persisting greater than
30 days after initial exposure to even four ounces of diluted urine.
Even on the most urine resistant grass tested (fescue) urine concentration
was a bigger problem than urine volume. Concentrated urine with
volumes as little as 30cc (one ounce) caused lawn burn even on fescue
grasses.
Problem
Area Avoidance Techniques
Where applicable, fences can be used to keep neighboring dogs from
eliminating on the lawn. Advising neighbors of the legality of leash
laws, where applicable, can restrict damage to areas near sidewalks
and on tree lawns/median right of ways. Unfortunately, no repellents
are universally effective although a variety of home remedies have
been tried. Hot and bitter products are most likely to have taste
or odor aversive properties to dogs. Most repellents function better
as taste repellents than to touch or odor repellents. Some odor
repellents may actually encourage a dog to overmark the strange
smell. Some of the better known commercial repellents have these
limitations as well. A newly developed motion activated sprinkler,
primarily designed to keep cats and rabbits out of gardens, may
have benefits for some yards. The sprinkler, may provide benefit
in small yards or at corners of front yards where damage is most
likely to occur; however, the presence of numerous squirrels, stray
animals or children may result in over-watering and very high water
bills if they continuously trigger this device.
In many cases,
the problem dog is a housemate to the homeowner. While somewhat
time consuming, walking the dog to a park or field away from the
house is a simple remedy to this. The time can be well spent since
exercise has physical and emotional benefits for both dogs and their
owners. Homeowners are encouraged to choose an appropriate destination
and not create problem lawns elsewhere that may affect the overall
aesthetics of the neighborhood.
A more feasible
approach may be to train the pet to eliminate in a designated area
of the yard. This area would be a landscaped area specifically designed
for the dog. It will need a substrate like pea gravel or mulch that
the dog finds acceptable and may even include a marking post like
a large boulder, bird bath, lawn ornament, or even faux hydrant.
Collecting the dog’s urine in a cup and using it in this area
for several days can provide some odor attractant value to this
area. Feces can also be collected and transported to the new, designated
area. Consistency for at least 2-3 weeks is important to establish
this as a routine, trained behavior; several months may be necessary
in some cases. Initially, training can occur with the dog on a short
leash and food rewards employed to encourage use of this area. Dogs
should not be unsupervised in the yard while this initial training
is occurring. It is often easier to train a young puppy to a particular
ground texture than an adult dog, but never impossible in any age
dog. A variable reward system utilizing one standard treat if urinating
anywhere outside and several treats or a special treat if in the
designated area can be helpful in this process and avoid confusing
the dog regarding the new housebreaking rules. Excessive food rewards
in the form of meat or protein products will contribute to increased
nitrogen content in the urine. Dogs that are being obedience trained
should not be trained with treats on the lawn during this housebreaking
or pets and reward systems can really become confused. Many dog
owners will also find it helpful to train their dog to an elimination
command during this time. Common commands might include: Potty,
Piddle, Do Your Business or Hurry Up, etc. and take less time to
accomplish the task when inclement weather is present or time schedules
are busy.
Dietary
Modification Techniques
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,
liquids 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 salt or garlic 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, increased 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 as well 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.
Repair/Recovery
of Damage Area
A leash can
function to bond owners to their dogs and increase the time pets
spend interacting with their owners. A leash can also be part of
a responsible neighbor policy, be a great training aid, and is also
one of the best ways to be at the site to intervene when urinations
occur. Watering the spot after urinations will accomplish the dilution
with no ill affects on the dog. Dr. Allard’s study looked at
watering fescue at different intervals following urination. Water
volumes three times that of the urine were used to assess their
dilution effects. A fertilizer effect rather than burn was noted
when the site was watered at any time up to 8 hours after the urination.
When the delay in watering was extended to 12 or more hours, progressively
worse burns were noted. It appears that routine watering of the
grass in early mornings would not be sufficient to prevent all urine
burns.
The use of gypsum
or lime has been advocated but it is uncertain exactly what mechanism
this would have in helping prevent urine damage. Improved soil quality
over time may result in better drainage and less urine concentration
at the grass and root level, but additional information is needed
in this area.
Lawn burn, when
mild, will often repair itself over time, especially in the case
of the warm-season turf grasses that spread by stolons and rhizomes.
Dark green spots and taller grasses may remain for several weeks.
Sodding can be a quick way to patch severely damaged individual
areas that would otherwise be invaded by weeds.
While a high
fence and dog-less lifestyle can ensure that "female dog spot
disease" is not a problem in your yard, homeowners and dog
lovers have several practical options available to manage this problem.
Communications should remain open whenever family conflicts arise
with various priorities. Coordinating a comprehensive program with
your county or state extension horticulturist or lawn care resource
and your veterinarian can keep your four-legged friend on good terms
and out of the dog house, so she, too, can enjoy romping in your
well manicured yard.
Resource:
1Allard, AW. Lawn burn and dog urine, Canine Practice, March/April
1981;8;(2);26-32.
Source:
Dr.
Steve Thompson, DVM
Director - Wellness Clinic/Community Practice
Companion Animal Medicine & Behavior
Veterinary Teaching Hospital
1249 Lynn Hall
West Lafayette, Indiana 47907-1249
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