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A
lthough cats are known for their fastidious elimi-
nation behavior, problem urination is one of the
most common feline behavioral problems for which
veterinary consultation is sought.
1-4
Excluding patho-
physiologic problems involving the urinary tract, prob-
lem urination can be divided into 2 subgroups: inap-
propriate urination and urine marking or spraying.
Inappropriate urination typically reflects disruption of
normal litter box or outdoor toilet behavior such that
cats change their toilet areas to inappropriate parts of
the house.
5
In contrast, urine marking is a normal
behavior, at least for sexually intact male cats, that pre-
sumably relates to territoriality and may be related to
repelling other males or gaining access to breeding
females.
6
When a cat urine marks, it typically main-
tains a standing posture with the hind limbs straight
and the tail up and quivering; the cat alternately steps
with the hind limbs and sprays urine on a vertical sur-
face. During urine marking, urine may also be directed
toward horizontal surfaces, and objects may be marked
while the cat adopts a squatting posture. Commonly
mentioned target objects are walls, appliances, and the
owner’s bed or clothing.
5
A commonly cited difference
between inappropriate urination and urine marking is
that with inappropriate urination, the litter box is typ-
ically not used for urination and, possibly, not for defe-
cation, whereas with urine marking, the litter box is
typically still used for urination and defecation.
5
Urine
marking is under hormonal control and is prevented in
about 90% of male and 95% of female cats by gonadec-
tomy.
7
Both behavioral (environmental management) and
pharmacologic approaches to the treatment of urine
marking in cats have been emphasized in the litera-
ture.
5,8,9
Open-label trials, in which no standard envi-
ronmental management was employed, revealed that
the behavior was eliminated or the frequency of urine
marking was markedly reduced in 55 to 75% of cats
treated with diazepam
10,11
or buspirone.
12
A recent
placebo-controlled double-blind study
13
combining
standard procedures for cleaning urine-soiled areas
and the litter box with administration of a selective
serotonin reuptake inhibitor (fluoxetine hydrochlo-
ride) resulted in ≥ 90% reduction in urine marking in
treated cats, compared with control cats. However,
because of differences in drugs and trial designs, the
degree to which environmental management (eg,
reduction of ambient urine odors) alone contributes to
the reduction of urine marking is unknown.
Information on the effects of environmental man-
agement alone on objectionable urine marking would
help in formulating an overall approach to treatment of
affected cats. The purposes of the study reported here
were to evaluate the effects of environmental manage-
ment on marking frequency in cats with urine marking
and to determine whether environmental management
had different effects in males versus females. The study
JAVMA, Vol 219, No. 12, December 15, 2001 Scientific Reports: Original Study 1709
SMALL ANIMALS/
EXOTICS
Causes of urine marking in cats
and effects of environmental management
on frequency of marking
Patricia A. Pryor, DVM, DACVB; Benjamin L. Hart, DVM, PhD, DACVB; Melissa J. Bain, DVM, DACVB; Kelly D. Cliff, DVM
Objective—To evaluate effects of environmental
management alone on marking frequency in cats with
urine marking and to obtain demographic data on cats
with urine marking and data on owner-perceived fac-
tors that contributed to urine marking behavior.
Design—Single-intervention study.
Animals—40 neutered male and 7 spayed female
cats.
Procedure—During a 2-week baseline phase, owners
maintained a daily record of the number of urine
marks. This phase was followed by a 2-week environ-
mental management phase during which owners
cleaned recently deposited urine marks daily,
scooped waste from the litter box daily, and changed
the litter and cleaned the litter box weekly while con-
tinuing to record urine marks.
Results—Male cats and cats from multicat house-
holds were significantly overrepresented, compared
with the general pet cat population in California. The
most commonly mentioned causative factors for
urine marking were agonistic interactions with other
cats outside or inside the home. Environmental man-
agement procedures resulted in an overall reduction
in urine marking frequency. Among cats that marked
≥ 6 times during the baseline phase, females were
significantly more likely to respond to treatment (≥
50% reduction in marking frequency) than were
males.
Conclusions and Clinical Relevance—Results sug-
gest that male cats and cats from multicat house-
holds are more likely to exhibit urine marking behav-
ior than females and cats from single-cat households.
Results also suggest that attention to environmental
and litter box hygiene can reduce marking frequency
in cats, regardless of sex or household status of the
cats, and may come close to resolving the marking
problem in some cats. (
J Am Vet Med Assoc
2001;
219:1709–1713)
From the Behavior Service, Veterinary Medical Teaching Hospital,
School of Veterinary Medicine, University of California, Davis, CA
95616.
Supported in part by Elanco Animal Health, a division of Eli Lilly
and Company; the Center for Companion Animal Health; and the
Friskies Petcare Residency Program in Clinical Animal Behavior at
the University of California, Davis.
The authors thank Dr. M. Watnik for assistance with statistical
analyses.
Address correspondence to Dr. Hart.
01_05_0183.QXD 10/15/2005 12:55 PM Page 1709
was also designed to collect demographic data on cats
with urine marking and data on owner-perceived fac-
tors that contributed to the initiation and continuation
of urine marking behavior.
Materials and Methods
Recruitment of subjects—The study was carried out at
2 clinical centers: the Veterinary Medical Teaching Hospital
of the University of California School of Veterinary Medicine
in Davis and the University of California Veterinary Medical
Center-San Diego. Advertisements (4 X 4 in) announcing the
study and soliciting participants were placed in the Sunday
and either the Tuesday or Wednesday editions of regional
newspapers. At the same time, letters announcing the study
were sent to veterinarians with the same zip codes as the
regional newspapers’ areas of delivery. The newspaper adver-
tisements and the letters to veterinarians listed the following
enrollment criteria: only 1 urine marking cat/household; ≥ 4
urine marks on indoor vertical surfaces/wk; ≤ 4 cats/house-
hold; the cat must have been neutered or spayed; and the cat
must not have been receiving any medication for the problem
behavior.
Calls from cat owners generated by the advertisements
and mailings to veterinarians were logged into a telephone
message system, and screeners contacted the cat owners and
conducted a screening interview. For owners whose cats
appeared to meet the enrollment criteria, an appointment
was made with a veterinary behaviorist at 1 of the 2 clinical
centers. There was no attempt in the recruitment advertise-
ments or letters to veterinarians or during the screening
interview to influence nomination of cats of a particular sex
or of cats from single-cat or multicat households. Seventy-
four enrollment appointments were completed with owners
of cats that appeared to meet enrollment criteria during the
screening interview.
Study design—During the enrollment appointment, an
extensive interview was conducted seeking information on
owner-estimated urine marking frequency and location of
urine marks. Owners were also asked to identify what they
perceived to be the causative factors for the initiation and
continuation of urine marking. When appropriate, owner-
identified causes were assigned to 1 of 5 categories: interac-
tion with cats outside the home, interaction with other cats
in the home, limiting the problem cat’s access to the out-
doors, relocation to a new home, and a change in the owner’s
daily schedule. However, owners were also given an oppor-
tunity to designate other causative factors. Only causative
factors listed by ≥ 3 cat owners were included in the tabula-
tion. If an owner listed > 2 causes, only the 2 most prominent
causes were included. If the cat was from a multicat house-
hold, owners were also asked how they determined which cat
was responsible for the urine marking. Most owners stated
that they only saw the nominated cat marking or that only
the nominated cat had access to the marked area. A judgment
was made as to the reliability of the owner’s report, and the
cat was included in the study only if the behaviorist believed
that the owner’s judgment was reasonably accurate.
Owners were required to sign a consent form outlining
their responsibilities during the study. A physical examina-
tion was performed, and a blood sample was collected and
submitted for a CBC and serum biochemical analyses. Urine
was obtained by means of cystocentesis (guided by means of
ultrasonography, if necessary) and submitted for urinalysis.
Following the enrollment appointment and review of hema-
tology and urinalysis results, 23 cats were excluded because
of abnormal physical examination, hematology, or urinalysis
findings or because of a failure to meet behavioral criteria
important to the conduct of the study. Owners of cats exclud-
ed from the study were given behavioral or medical advice
for resolving the problem urination on a case-by-case basis.
The study included a 2-week baseline phase and a 2-
week environmental management phase. During both phas-
es, owners of cats recorded, on a daily basis, the number and
location of urine marks. Only marks on vertical surfaces were
used in data analyses, as they are a better indicator of urine
marking than are marks on horizontal surfaces, which may
be attributable to inappropriate elimination. During the 2-
week baseline phase, owners were instructed to not change
the cats’ environment or their manner of cleaning the litter
box or cleaning urine deposits and to not physically punish
the cats for urine marking.
During the 2-week environmental management phase,
owners were provided with verbal and written instructions
on instituting standardized environmental management pro-
cedures involving cleaning of urine marks and litter box
hygiene. Owners were instructed to clean, on the first day of
the environmental management phase, all detectable urine
marks on vertical and horizontal surfaces, using an enzymat-
ic cleaner
a
that was provided to them. Additionally, owners
were instructed to clean all solids and liquids from the litter
box once daily and to completely change the litter material
and wash the litter box once a week. For households with
> 1 cat, owners were instructed to provide sufficient litter
boxes so that the number of boxes equaled the number of
cats plus 1. These were the only environmental and behav-
ioral management procedures to be implemented. No change
in the configuration of the litter boxes or type of litter was
specified.
Owners were given forms on which they were required
to enter the number of urine marks each day throughout the
4 weeks of the study. Owners were contacted on day 3 or 4 of
the baseline phase to review the procedures and answer ques-
tions. Information about urine marking frequency and loca-
tion was collected from the owners during weekly telephone
calls and recorded on similar forms in the investigator’s
office. Owners were instructed to mail their forms to the
investigators at the end of the study, and an audit was per-
formed to ensure that values obtained during telephone con-
versations were identical to those on the forms returned by
mail. Any discrepancies were resolved by a telephone call.
Data analysis—Data collected during the enrollment
interview were used to compare sex and household status
(multicat vs single-cat household) of enrolled cats with sex
and household status of the California cat population,
14
to
determine owner-perceived factors associated with the initia-
tion and continuation of urine marking, to determine how
cat owners typically identified urine marks and determined
which cat in a multicat household was marking, and to iden-
tify common urine marking targets.
Data collected during the baseline phase of the study
(weeks 1 and 2) provided a comparison between the fre-
quency of urine marking estimated by the owner during the
enrollment interview and the actual number of daily marks.
Data collected during the environmental management phase
of the study (weeks 3 and 4) were compared with baseline
data to provide information on the overall effect of environ-
mental management on the frequency of urine marking for
all cats, as well as for a subgroup of cats that marked ≥ 6
times during the 2 weeks of the baseline phase. Data for week
4 were compared with data for week 3 to determine whether
there was a lead-in time that might be associated with any
decrease in urine marking behavior brought about by the
environmental management. A cat was considered to have
responded if the recorded urine marking frequency during
the environmental management phase was ≤ 50% of the fre-
quency during the baseline phase.
Statistical procedures—A z-test of proportion was used
1710 Scientific Reports: Original Study JAVMA, Vol 219, No. 12, December 15, 2001
SMALL ANIMALS/
EXOTICS
01_05_0183.QXD 10/15/2005 12:55 PM Page 1710
to determine whether the distribution between sex and
household status among cats meeting enrollment criteria dif-
fered from that of California households. Based on previous
findings,
7
we predicted that among cats meeting the enroll-
ment criteria (spraying ≥ 4 times/wk), males and cats from
multicat households would be overrepresented; these tests
for significance were therefore 1-sided.
Paired t-tests with log transformations to achieve nor-
mality of data were used to compare the number of urine
marks during week 1 with week 2 and during week 3 with
week 4. After examining the suitability of combining data
from weeks 1 and 2 (baseline phase) and combining data
from weeks 3 and 4 (environmental management phase), a
paired t-test with log transformation was used to test the
hypothesis that environmental management would reduce
urine marking frequency. Data were also examined to test the
hypothesis that 1 sex might respond more to environmental
management than the other sex. To carry out this latter
analysis, a comparison was made between the males and
females marking ≥ 6 times in the 2 weeks of the baseline
phase with regard to those categorized as responding to envi-
ronmental management (≥ 50% reduction in urine marking
frequency from baseline). The 1-factor ANOVA test with log
transformation to achieve normality of data distribution was
used for comparison. Finally, a similar comparison of respon-
ders between sexes was made for cats from only multicat
households, using a Fisher exact test. With the exception of
the demographic comparisons between cats meeting enroll-
ment criteria, all tests were 2-sided. For all analyses, values
of P < 0.05 were considered significant. Statistical procedures
were performed by use of a computer program.
b
Results
Study participants—Screening interviews were
conducted with owners of 418 cats, and enrollment
appointments were made for 74. Of these 74 cats, 57
(77%) were male, and 17 (23%) were female. This was
similar to the sex distribution of the 320 cats for which
information on sex was obtained during the screening
interview (the remaining 98 cats were screened out
before information on sex was obtained). Of these 320
cats, 229 (72%) were male, and 91 (28%) were female.
Of the 74 cats examined during an enrollment
appointment, 23 were excluded because hematologic
or serum biochemical abnormalities were identified (n
= 7), there was an insufficient number of urine marks
or duration of marking (4), indications of owner non-
compliance were identified (4), there were too many
cats in the household (3), more than 1 cat in the
household was marking (3), results of a urinalysis were
abnormal (2), an abnormality was identified during
physical examination (1), the cat was too old (1), or
the cat had a history of recurrent cystitis (1). Some cats
were excluded for more than 1 reason. An additional 3
cats were excluded because they did not mark during
the 2-week baseline phase. One additional cat was
excluded because the owner did not comply with
instructions. The remaining 40 male and 7 female cats
completed the baseline and environmental manage-
ment phases of the study.
Causative factors for urine marking and detec-
tion of urine marks—The 3 most common causes of
urine marking listed by owners of the 47 cats that com-
pleted the study (owners of several cats indicated > 1
factor) were agonistic interactions with cats outside the
home (23 cats; 49%), agonistic interactions with other
cats in the home (13 cats; 28%), and limiting the cat’s
access to the outdoors (12 cats; 26%). Other factors
that were cited included relocation to a new home (4
cats; 9%), introduction of a new inanimate object to
the home (3 cats; 6%), a change in the owner’s daily
schedule (3 cats; 6%), and interaction with the owner
(3 cats; 6%). Owners of 10 (21%) cats did not know of
a causative factor.
Owners listed the following methods used to
detect fresh urine marks: sight (92%), odor (72%),
observed cat marking at least once (21%), felt marks
through contact (15%), and observed the problem cat
or another cat investigating the marked area at least
once (6%). Owners commonly used > 1 method to
detect urine marks.
Owners listed the following targets for urine mark-
ing: furniture (91%), walls or windows near the point
of interaction with cats outside the home (87%), other
walls (72%), appliances (47%), novel items (23%), and
pet-associated items such as the litter box or toys
(13%).
Of the 47 cats, 42 (89%) were from multicat
households. The most common method by which
owners detected which cat in a multicat household was
marking was observing the problem cat mark at least
once (69%). In some instances, the problem cat was
separated from nonproblem cats at least once when
marking occurred (5%). Other methods mentioned
included finding the problem cat in the marked area,
noticing that other cats stayed away from the marked
area, and noticing that the problem cat would hide
after marking. In some instances, the problem cat had
marked before other cats were adopted into the house-
hold. Some owners provided > 1 method by which
they identified the marking cat and determined that
this was the only cat in the home that was marking.
Sex and household status of enrolled cats—Male
cats were significantly (P < 0.001; 1-sided z-test of pro-
portions) overrepresented in the study (85% male), com-
pared with the general population of pet cats in California
(49% male). Similarly, cats from multicat households
were significantly (P = 0.032; 1-sided z-test of propor-
tions) overrepresented (89% resided in multicat house-
holds), compared with pet cats in the general population
in California (78% resided in multicat households).
Frequency of urine marking—Frequency of urine
marking estimated by cat owners during the enroll-
ment interview ranged from 4 to 35 marks/wk. During
the baseline phase of the study, however, the frequency
of urine marking ranged from 0.5 to 15.5 marks/wk.
For some cats, the frequency of marking during the
baseline phase varied considerably from that estimated
by cat owners during the enrollment interview.
Twenty-nine owners overestimated the marking fre-
quency. One owner estimated during the enrollment
interview that the cat marked 21 times/wk, but the cat
actually marked only 2 times/wk during the baseline
phase. Nineteen owners underestimated the marking
frequency, and 4 accurately estimated the marking fre-
quency as recorded during the baseline phase.
JAVMA, Vol 219, No. 12, December 15, 2001 Scientific Reports: Original Study 1711
SMALL ANIMALS/
EXOTICS
01_05_0183.QXD 10/15/2005 12:55 PM Page 1711
Effects of environmental management—The
number of urine marks recorded by the owners during
week 1 was not significantly (P = 0.539; paired t-test)
different from the number recorded during week 2.
Similarly, the number recorded during week 3 was not
significantly (P = 0.45; paired t-test) different from the
number recorded during week 4. Therefore, data from
the 2 weeks of the baseline phase were compared with
data from the 2 weeks of the environmental manage-
ment phase. Number of urine marks recorded during
the environmental management phase (mean ± SE, 9.7
± 1.3 marks) was significantly (P < 0.001; paired t-test)
less than the number recorded during the baseline
phase (11.7 ± 1.0 marks).
Forty cats (33 males and 7 females) marked ≥ 6
times during the baseline phase. For these cats, num-
ber of urine marks recorded during the environmental
management phase (mean ± SE, 10.70 ± 1.50 marks)
was significantly (P < 0.001; paired t-test) less than the
number recorded during the baseline phase (12.93 ±
1.03 marks). Of the 7 female cats marking ≥ 6 times
during the baseline phase, 5 (71%) were classified as
having responded to environmental management
(≥ 50% reduction in urine marking frequency during
environmental management phase, compared with
baseline phase), whereas only 12 of the 33 (36%) male
cats were classified as having responded to environ-
mental management. The percentage of females that
responded was significantly (P = 0.003; ANOVA) high-
er than the percentage of males that responded. When
data were analyzed only for those cats that marked ≥ 6
times during the baseline phase and lived in multicat
households (30 males, 7 females), the proportion of
females that responded with a ≥ 50% reduction in
urine marking frequency (6/7; 86%) was still signifi-
cantly (P = 0.005; Fisher exact test) greater than the
proportion of males that responded (5/30; 17%). There
were too few cats from single-cat households to ana-
lyze response rates for these cats. In examining the
proportion of cats in which marking frequency was
reduced from ≥ 6 marks during the baseline phase to
≤ 1 mark during the environmental management
phase, this occurred in 2 of 7 (29%) female cats but in
only 2 of 33 (6%) male cats.
Discussion
Results of this study should help improve our
understanding and treatment of urine marking behav-
ior in cats. However, certain limitations of the study
should be considered. Most importantly, owners of
affected cats were recruited by use of newspaper adver-
tisements and letters to veterinarians, and cats were
enrolled in the study only if certain criteria were met,
including the stipulation that cats from multicat
households had to be the only cat in the household
that was marking. Fulfillment of this criterion relied on
the owner’s observations and the clinician’s judgment
of the reliability of the owner’s observations, and it is
possible that owners were mistaken in some instances.
However, a recent placebo-controlled double-blind
study
13
of the effects of fluoxetine on urine marking in
cats used the same method of evaluating owner obser-
vations with regard to determining which cat was
marking. In that study, all treated cats had a ≥ 90%
reduction in marking frequency, whereas none of the
control cats responded to this degree, and the mean
marking rate for control cats actually increased slight-
ly. These results attest to the adequacy of relying on
owner observations in this regard, because results
would not have been this clear-cut if some cats that
were believed to be urine marking had been misidenti-
fied. In addition, veterinarians in clinical practice must
rely on owner observations when deciding which cat in
a multicat household to treat for urine marking.
There were 5.7 times as many male as female cats
enrolled in the present study, and male cats were sig-
nificantly overrepresented relative to the pet cat popu-
lation in California. This finding is in line with results
of a previous study
7
that found about twice as many of
neutered males as spayed females started urine mark-
ing as adults. Although not as striking as the sex dif-
ference in cats meeting enrollment criteria, the present
study also found that cats from multicat households
were overrepresented, compared with those from sin-
gle-cat households. This finding was also similar to
previous findings.
7
These data may be useful during
preadoption counseling of clients.
Baseline daily observations of urine marking fre-
quency were often disparate from frequencies estimat-
ed by the owners during the enrollment interviews.
This suggests that in treating cats with urine marking
behavior, owners should be given instructions to
record each occurrence of urine marking behavior
before and after initiation of treatment so as to ade-
quately evaluate progress.
Information about causative factors reported by
owners in the present study may be useful when advis-
ing clients about how to resolve existing problems.
Again, this information relied on owner observations,
but currently no other method is available for collect-
ing such information for a large number of households
with cats. Agonistic or unfriendly interactions with
other cats outside the home or with other cats in the
home were the 2 factors most commonly associated
with the initiation or continuation of marking. If inter-
actions with cats outside the home are a causative fac-
tor, then blocking windows where cats visually interact
with outside cats may reduce the urine marking behav-
ior. If interactions with cats inside the home are a fac-
tor, then making household arrangements to reduce
the opportunity for agonistic interactions may prove
useful in decreasing the frequency of urine marking.
Environmental management procedures used in
the present study consisted of providing a sufficient
number of litter boxes, scooping waste from litter
boxes once a day, changing litter boxes weekly, and
cleaning all urine marks with an enzymatic cleaner, as
published data suggest that enzymatic cleaners result
in the most effective removal of urine odors.
15,16
These
environmental management procedures alone signifi-
cantly reduced the frequency of urine marking.
However, among cats that marked ≥ 6 times during the
baseline phase, females were more likely to respond to
treatment (≥ 50% reduction in marking frequency)
than were males. This suggests that the ambient level
of urine or fecal odors may be more important in main-
1712 Scientific Reports: Original Study JAVMA, Vol 219, No. 12, December 15, 2001
SMALL ANIMALS/
EXOTICS
01_05_0183.QXD 10/15/2005 12:55 PM Page 1712
taining urine marking in females than males. However,
results of the study do suggest that attention to envi-
ronmental and litter box hygiene can reduce marking
frequency in cats, regardless of sex or household status
of the cats, and may come close to resolving the mark-
ing problem in some cats.
a
Anti-icky-poo, Mister Max Quality Products, Lakeside, Calif.
b
SAS system for Windows, version 8.01, SAS Institute Inc, Cary, NC.
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