VetInfo Digest                    July 1999

This Month:

Aggression Between Cats
The ONE Thing Not to Say to Your Vet
Estimating the Age of Pets
What Do Kidneys Do?
Interesting Questions from This Month
How Often DO I Get Bit?
 

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Aggression and Cats

Over the last few months we have received a number of requests for
information on how to handle problems with aggressive cats. Of all the
areas of veterinary medicine, behavioral issues are the hardest for me. I
don't feel like an expert in these areas and we do not do much behavioral
counseling in our practice. Please keep in mind that the following
information is based on reviewing literature sources rather than my
personal experience.

There have been several reviews of feline aggression that categorized types
of aggressive behaviors seen in cats. I think that the most helpful method
of categorizing aggression is to consider the underlying causes of the
aggression and use these as the basis for sorting out the aggressive
behaviors. Using this line of thought there are eleven categories of
aggression suggested by Dr. Karen Overall in her book "Clinical Behavioral
Medicine for Small Animals".

They are: Aggression as a lack of socialization, play aggression, fear
aggression, pain aggression, intercat aggression, maternal aggression,
predatory aggression, territorial aggression, redirected aggression,
assertion of status related aggression and idiopathic aggression.

Of these categories, idiopathic aggression simply means aggression that can
not be explained using the other categories or aggression that occurs for
no obvious reason.

It is important to understand that some forms of aggression are normal
behavior that just doesn't fit in well with the lifestyle of the cat's
owner. At other times, the aggressive behavior may be a normal behavior
pattern that is exaggerated beyond what can be considered normal in a
particular patient.

The type of aggression that we receive the most questions about is
inter-cat aggression, so this month, we'll start with this one and then
hopefully cover more of them in future issues.

Cats are not as social as dogs. In nature, cats tend to establish and
defend a territory which may overlap some with the territory of other cats
but which usually has a central area that the cat will defend more
vigorously. Cats do interact in the wild, both for reproductive purposes
and for social purposes, but the interactions are much less structured than
those of dogs and other more social creatures. Sometimes one or more cats
will form a close attachment under natural circumstances, hunting together,
providing mutual grooming or other social interactions.

When two or more cats are kept in the same household, their situation is
different from what they might encounter if feral. Cats in this situation
must interact to some degree. If one or more of the cat's natural tendency
is to keep and hold a territory there is likely to be aggression. If the
cats can form a close social bond there may be aggressive play but it is
less likely to lead to real injuries.

Cats defending a territory are actually trying to injure the cat they
consider to be an invader in their home when they attack, in most
circumstances. For first time cat owners who may have owned dogs, this can
be startling, since dogs often engage in noisy and furious encounters in
which no one is injured but one dog gives in eventually. In cat aggression,
most of the time the cat being attacked is actually likely to suffer injury
if it can not get away or the aggressive act is not interrupted.

After a couple of attacks, the cat who is the victim of the attacks may
develop such a nervous reaction to the presence of the other cat that it
actually provokes further attacks by its demeanor. Sometimes, in a
multiple cat household, this produces a kind of chain-reaction situation in
which one cat begins to act aggressively and then others are induced to
attack the original victim as it becomes more and more nervous, and thus
abnormal, in its behavior.

Conversely, the attacking cat may become much more confident in its ability
to defend its territory and be a little more likely to attack as time goes
on. It is very hard to change a behavior that is strongly reflective of the
normal behavior for a species and this is very true of territorially
induced aggression between cats. In most cases the best that can be hoped
for is to relieve the territorial stress or alter the situation enough that
aggressive acts are less likely to occur.

There are a number of behavioral modifications that have been tried in
efforts to reduce aggressiveness between cats. As is often true of
behavioral problems, none of these modifications are going to work for all
situations.

The aggressor cat can be thought of as having territorial stress. He or she
wants to have an area that is its alone. The depth of this desire depends
on part in how stimulated the cat is to feel the need for territorial
privacy. If an indoor cat has been fine but suddenly becomes aggressive
towards house mates when it sees an outdoor cat coming close to the house,
the reason may be an increase in the territorial stress level this cat
feels. If a cat has been living well with a house mate or house mates and
then one cat is removed from the household due to medical illness the
balance of the household may be different when the ill cat returns. It is
not unusual for cats to suddenly become aggressive towards a cat that it
formerly appeared to accept as a house mate after one of the cats has been
taken out of the home for more than a day or so.

Urinating or defecating in the house can occur early in territorial
disputes prior to overt aggression. Both of these behaviors can be part of
the marking of territory. A cat that is anxious about its territorial
rights may suddenly begin to urine mark or defecate when this behavior was
not previously present. Sometimes this occurs in higher places than might
be expected, like beds or counters. Anti-anxiety medications used at the
very start of this sort of behavior may avert further development of the
problem and later aggressive behavior but this is hard to really prove
since these behaviors do not always lead to aggression.

Once a cat reaches the point that it wants to aggressively defend its
territory there are a few things that can be done that are sometimes
helpful. Cats that are stimulated to aggression by presence of an outdoor
cat may actually do much better if they are allowed outside, too. This
obviously presents a whole new set of risks for this cat and the decision
to let a cat outside to treat for aggressive behavior has to be taken
seriously. Outside the cat may be hit by a car, find itself the victim of
an even more aggressive cat or fall into other troubles unique to the
outdoors. Alternatively, shutting the blinds and blocking access to
doorways or other areas that the outdoor cat may be marking on might lessen
the stress level enough to allow aggressive behavior directed towards house
mates to subside. Keeping the aggressive cat separated from the victim may
be the only way to stop territorial aggression. Sometimes, after a "cooling
off" period, it is possible to reintroduce the cats gradually without a
recurrence of fighting but this is not something that can be counted on.

When it is necessary to separate cats into their own "territories" inside
the house, it is important to remember that they both will need access to a
litterpan, to food and to water without having to interact with the other
cat at all. In some cases it is possible to fit an inside door with a cat
door that is activated by a special collar on one of the cats -- and to let
the cat that is being attacked have the collar. This gives the cat a place
to get away when it needs to and may lead to a sort of compromise among the
cats in which they can interact at least some of the time. Behaviorists
usually recommend giving the cat that is being attacked more freedom or the
better parts of the house but I have never seen this tendency justified in
any manner so it may be just human sympathy for the "attackee" that leads
to this recommendation. If it is impossible to provide separate territories
it may be necessary to find a new home for one of the cats. The prognosis
for a future in which the cats can live together is better if the
aggressive cat shows some sign of caution in the approach to the attack --
stalking first, hissing and spitting or other behaviors that signal the
attack. Cats that just instantly attack when they see the other cat are
more likely to be exhibiting strong territorial aggression that is less
likely to respond to treatment.

Medical therapy is always tempting to try when behavioral problems are
present. It would be really nice if a pill was invented that would safely
and reliably stop aggression and other behavioral problems but I don't know
of a magic cure yet. There are some medications that are sometimes helpful,
though.

The aggressive cat may respond to medical therapy. Anti-anxiety medications
such as diazepam (Valium Rx) and buspirone (BuSpar Rx) have been used in
aggressive cats. Sometimes these compounds work but in other cases they
actually lower the aggression threshold -- so they have to be used with
caution. Selective seritonin reuptake inhibitors (SSRIs) such as fluoxetine
(Prozac Rx) have been used to treat the aggressive cat, based on research
in other species which indicates that low seritonin levels in the brain may
lead to aggressive behaviors. Tri-cyclic antidepressants such as
amitriptyline (Elavil Rx) can also be helpful in some cases of aggression.
Recently, clomipramine (Clomicalm Rx, Anafranil Rx) has been advocated for
treatment of aggression since it seems to some of the action of the
tri-cyclic antidepressants and the SSRI medications. Our clinical
experience has mostly involved amitriptyline since it is inexpensive and is
relatively easy to obtain. We think we have had some success with this
medication but definitely do not view it as a "cure-all" for aggression.

As odd as it sounds, it may be more important to treat the cat that is
being attacked with medications than to treat the aggressor cat. For the
victims of attack, the favored medications are the anti-anxiety medications
such as diazepam and buspirone. Because they have some anti-anxiety effects
there are advocates of amitriptyline and clomipramine for the victim cat as
well. The theory is that the anxiety exhibited by a cat worrying about
being attacked actually increases the likelihood that it will be attacked.
This effect has even been noticed in humans. A study done on victims of
child abuse showed that they were more likely to be abused in foster homes,
too --- apparently because of learned reactions to the previous abuse. We
have tried treating the cat being attacked in our practice and this has
also been beneficial on occasion.

If medication and separation seem to have reduced the likelihood of further
aggressive behavior it may be worthwhile to try to reintroduce the cats. It
is necessary to do this when the cats can be supervised. It might help to
put a bell on the collar of the aggressive cat so that sudden attacks will
be audible. It is also a good idea to have an air horn or water pistol
handy in order to be able to halt an act of aggression by startling the
aggressive cat. A handy escape route for the victim cat is also useful. It
may help to keep the aggressive cat in a cat carrier for a few weeks while
allowing the previous victim to have free run of the house. This allows the
cats to get used to each other's presence again without an actual fight and
it may help to establish the less aggressive cat's right to the territory.
A really aggressive cat intent on having the house to itself isn't going to
be impressed by this but it may help in marginal cases.

Inter-cat aggression is one of the most frustrating behavioral problems,
since the underlying behavior is a normal behavioral pattern for cats that
just doesn't fit into the lifestyle imposed by humans. It may take a lot of
accommodating on the part of the humans in the situation to control this
problem. If you are living with cats confined to separate rooms in the
house you are definitely not alone.

Amitriptyline (Elavil Rx)
1.1 mg/kg twice a day or 5- 10 mg /cat /day. General chem panel
recommended prior to use of this medication and after several weeks of
treatment

Buspirone (Buspar Rx)    5mg twice daily

Clomipramine    (Clomicalm Rx)
0.5mg/kg of body weight, once daily. Correct dosing is important with
this medication as overdose is possible.

Diazepam (Valium Rx)
1 to 2.5mg/cat, two or three times daily. Check liver enzyme levels prior
to use and after a few days of use for optimum safety ( sometimes causes
liver disease in cats )

Fluoxetine (Prozac Rx)    1mg/kg of body weight, once a day

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The Top ONE Thing Not to Say to Your Vet

Last month I wrote a top ten list of things not to say to your vet and I
forgot the most important one.

Never ever tell your vet that you sued your last vet. Don't even tell your
vet that you thought about suing your last vet. I don't think that many
vets have a problem with legitimate suits against veterinarians for
malpractice. The problem is that most threatened lawsuits are really the
result of miscommunications between a vet and client, financial disputes
and unfortunate outcomes despite reasonable treatment efforts on the part
of the vet. All three of these reasons for lawsuits make vets cast a
jaundiced eye upon a prospective client with a history of suing a vet.
There is a reasonable presumption that a person who has these problems with
one veterinarian may have the same problems at the next veterinarian's too.

Get to know your vet before you talk about problems with a previous
veterinarian. Even if you didn't sue or even if you really believe that
there were problems that were not your fault. If there is a specific
problem that you had with a previous vet, such as removing your pet from
the examining room for treatment procedures or failing to provide an
estimate for services, you may wish to state your preferences and ask what
the new vet's policy is. In fact, I think it is perfectly reasonable to
schedule a time to talk to the veterinary staff, tour the hospital and ask
a few questions prior to bringing your pet to a veterinary hospital. The
veterinarian will understand that you are particular about the care of your
pets -- and you won't have to mention that you were really unhappy with a
previous vet.

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Estimating the Age of Pets

Lots of people ask us to estimate the age of their newly acquired dog or
cat. This is particularly true of pets adopted from shelters or adopted as
strays. There are really only a few times in a dog or cat's life when
estimating its age can be done with reasonable accuracy.

Puppies and kittens have all their deciduous teeth by the time they are six
weeks of age. Kittens lose their "baby" incisors when they are about 3.5
to 4 months of age. Puppies usually wait until four months of age to lose
their deciduous incisors. This is the first time that a fairly accurate age
can be established in a puppy or kitten with all of its deciduous teeth.

Both puppies and kittens tend to have the first appearance of their
permanent canine teeth (the four large "fangs") at about 5.5 to 6 months
of age. The eruption of these teeth is the second time when age can be
estimated with some accuracy.

Many vets try to use tartar accumulation to roughly estimate age of young
adult cats and dogs but this is not an accurate way to estimate age. There
is a lot of variability in the time that tartar accumulates on the teeth of
individual dogs and cats. Loss of pigment in hair color is another fairly
unreliable sign of age. There are a lot of golden retrievers and Labrador
retrievers who have gray muzzles at three years of age and a lot of little
terriers who don't gray until they are fifteen or sixteen years old. Cats
do not seem to have much tendency to get gray at all in many cases.

It is possible to make a rough but usable estimate of age in dogs older
than eight and cats older than twelve. The lens of the eye is clear because
it has no internal blood supply and because it is composed of fibers that
line up in a manner that makes them transparent. More fibers are added as
dogs and cats age. These fibers eventually compress the center of the lens,
making it cloudy in the center. When this cloudiness, known as nuclear
sclerosis, first begins, it is possible to estimate that a dog is eight
years of age and that a cat is about twelve years of age. This sign has to
be watched for but most vets will notice it on the yearly physical exam. It
is helpful to know when pets are reaching their "geriatric" years in order
to tailor their health needs to their age. If we can estimate the pets age
within a year or two by using this method it helps us make future health
decisions. Ask your vet to watch for this sign if your pet's age is
uncertain. It's easier than finding their birth certificate!

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What Do Kidney's Do?

The liver isn't the only organ in the body that has a heavy workload. The
kidneys do a lot more than cleanse toxins from the blood and produce urine,
the two things that they are best known for.

Kidneys are vital in keeping toxins out of the blood stream. Some toxins
just passively flow out of the body with the production of urine. Other
toxins have to be actively captured from the bloodstream and forced into
the urine. The kidneys have the ability to recognize and selectively
remove a number of substances from the body. They have to do this without
losing or wasting substances that the body needs to preserve, so there are
also selective mechanisms for conserving potassium, proteins and other
vital substances in the blood stream.

When the kidneys are young and working well, they are easily able to
perform their filtration duties. In fact, dogs and cats are born with
kidney capacity that far exceeds their usual needs. Approximately
two-thirds to three-quarters of the kidney's filtration cells have to die
or quit working before there is a noticeable drop in kidney function. Even
at that point the kidney cells have an amazing ability to work harder to
make up for the loss of their mates in a process known as hypertrophy.
They are much like a muscle in this regard. When the need arises for the
cells to do more work they just learn how to work more efficiently. This
ability is especially noticeable in cats, who often live years after the
loss of much of their kidney function if they are cared for in a manner
that helps the remaining kidney cells do their job better.

Kidneys produce the hormone that stimulates the bone marrow to make red
blood cells, erythropoeitin. This hormone is made in response to low oxygen
levels in the kidney. In older cats with renal failure inadequate
quantities of erythropoeitin are produced which leads to anemia. In severe
cases, it may be necessary to try to supplement this hormone with a human
origin source of erythropoeitin (Epogen Rx). Unfortunately, because there
is enough difference between this protein and the one naturally produced by
cats for their body to notice, antibodies against Epogen are produced
quickly in many cats, limiting the long-term usefulness of the medication.

Blood pressure is controlled in part by the kidneys, which are very
dependent on good blood flow to work properly. The kidneys will strive for
higher blood pressure when they are not working well, even if it is
detrimental to the rest of the body. In some cases, the blood pressure will
even get high enough to be bad for the kidneys but they will still attempt
to keep the pressure high when they are failing. Kidneys produce a
substance, renin, which activates angiotensinogen to produce angiotensin I.
A second enzyme, angiotensin converting enzyme (ACE) acts to change
angiotensin I to angiotensin II, the active form of the hormone. This is
why one of the newer recommendations for cats and dogs with renal failure
is to use an angiotensin converting enzyme inhibitor (ACE inhibitor) to
stop this process and lower blood pressure. This may not be quite as good
for the kidneys but it may stop the cat from developing heart failure or
blindness from the high blood pressure.

Calcitriol, an active form of Vitamin D, is produced exclusively by the
kidneys. This vitamin suppresses parathyroid hormone production which helps
to regulate the calcium and phosphorous levels in the body. In some cases
the production of this hormone will decrease before there are other obvious
signs of kidney failure. Due to this, supplementation of this hormone is
currently thought to be beneficial for most cats and dogs experiencing
renal failure.

The kidneys play a vital role in regulating the acidity of the blood
stream. When the kidneys are working properly they capture hydrogen ions
from the blood stream, reducing the acidity. Damage kidneys do not do this
as well, leading to acid conditions in the blood. This can cause the kidney
damage to worsen and affects many other bodily systems, as well. This is
the reason that the diets made for lower urinary tract disease in cats are
not a good idea to feed to cats with kidney failure (diets such as Hill's
c/d, Purina's UR, Alpo Urinary Formula, etc.). It is important to remember
that lower urinary tract disease is not a disease of the kidneys even
though they are part of the urinary system.

Kidneys are surprisingly versatile organs. They do a lot more than just
filter the waste products from the bloodstream. It is essential to take
signs of kidney disease seriously and start treatment early and
aggressively, remembering that it may eventually be necessary to provide
supplemental help for ALL the jobs the kidney does as kidney disease
progresses

Interesting Questions from This Month

How many feet of intestine does a dog or cat have?

The best way to estimate the length of the intestinal tract in a dog is to
multiply the length of the dog's body from his nose to his tail by five. So
a dog that is three feet long from her nose to the base of her tail (not
the tip) has about 15 feet of small intestines. This gives a rough
estimate of the number of feet of small intestine. Then add about three or
four feet for the large intestine and you have the length of the intestinal
tract.

How long does it take for food to leave a dog's stomach?

It can take up to 17 hours for a meal to completely clear out of the
stomach of a dog or cat. Both species can sometimes expel all the food in
as short as four hours, as well. Gastric emptying times longer than 17
hours or shorter than 4 hours are considered to be abnormal. We usually get
asked this question after a dog or cat throws up a meal the day after
eating it and it still looks like his or her regular food.

How much protein should I feed my dog or cat when I am trying to feed a low
protein diet for liver or kidney disease?

Dogs need at least 1.9 grams of protein per kilogram of body weight
(roughly 1 gram per pound of body weight) to ensure they will not have a
protein deficit. An effort should be made to get close to this amount
without taking a risk of going below it.

Cats need more protein than dogs. It is probably better to shoot for 2
grams per lb. of body weight in the cat or 18% of the total calories in the
diet from protein.

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How Often Do You Get Bit?

People ask me frequently how often I get bit by my patients. I probably get
bitten about twice a month by cats but most of the time they aren't too
serious about it and all I get is a small bruise or minor puncture wound.
Cat bites get infected easily, so I do immediately cleanse any bite that
breaks the skin with an antiseptic soap. I get bit by dogs much less
frequently, but usually the bites are more severe because dogs seem to be
serious about the attack more often than cats, at least in our office.

The worst dog bite I ever received came as a complete surprise to me. I
worked in a veterinary hospital that had two doors to each exam room, one
that the client entered with their pet and one on the opposite end of the
room that the staff entered from the treatment room.

I opened the door to the treatment room one day and said "Hi, Mr. Carter,
how are you and Star doing today?" Just about the time I got to the end of
the sentence Star had launched himself from the floor to my arm. He was a
large German shepherd and he clamped down hard on my right forearm and hung
on. In a reflex action, I swung my left arm at his head.

Dogs have faster reflexes than humans. At least faster than this human. He
let go of my right arm and clamped just as hard on my left arm.

Having some capacity to learn from my mistakes, I didn't swing at him
again. I slid my right arm up his chest and grabbed him by the collar. Mr.
Carter's admonitions of "Star, be a good boy now,' weren't working well, so
I just held on. One of the hospital technicians saw the flurry of activity
and arrived with a rabies control pole. Slipping the end over Star's neck
she managed to make him mad enough to let go of me and attack her, which
gave her time to snug the loop of the rabies pole and give us control over
Star.

Mr. Carter said "You know, they always made me bring Star in with a muzzle
on at the vet's in Philadelphia". It wasn't the right thing to say at the
time.

I have received two bad cat bites in my career. The first occurred at the
veterinary hospital I was working at between my sophomore and junior years
in veterinary school. A cat that was at the hospital for rabies
observation rushed past me as I came to work one morning, followed by the
fastest kennel worker and then a stream of progressively slower employees
of the hospital.

"Grab that cat!" someone yelled. So I did. Unfortunately, the cat had
achieved a high level of excitement and managed to twist completely around
in its skin and bite right through my left thumbnail. Knowing it was a
rabies suspect, I just couldn't let go, so I ran into the hospital and then
shook the cat off my thumb.

The reason that pets that have bitten someone are quarantined for ten days
is that dogs and cats can only transmit rabies in the last four to five
days of their life, if they are infected with the rabies virus. After that,
the virus is uniformly fatal. So if a pet lives ten days after biting
someone there is almost no chance it could have transmitted rabies to them.

This cat lived for two more days, having lived four days since biting its
owner and two days since biting me. It was a long week waiting for the
rabies test results from the state diagnostic lab. Fortunately, they were
negative and I didn't have to get the rabies series, which was still the
old, very uncomfortable vaccine at that time.

The next time I was bitten hard by a cat occurred at a rabies clinic. For
the life of me I can't understand why people cart their pets to rabies
vaccination clinics, stand in line with frightened pets and then take the
risk that they will get away in a school or public health building parking
lot. But they do.

The cat that bit me was typical of the cats I see at clinics. It really
just wanted to get away from the whole situation. I was just in the way. A
quick bite would probably make me move and allow it to bolt for the woods
behind the school. The only thing was that this particular quick bite
happened to pierce the artery at the base of my thumb. Since I was at a
high adrenaline point, too, my blood pressure was fairly high. Blood
spurted out of the arterial puncture, through the car window and all over
the cat's owner. I was able to stop the bleeding pretty quickly. I
vaccinated the cat and sent it home. Someone called 911 and the local
doctor came to tend the bite (this is an advantage of living in a rural
area, the 911 dispatchers sometimes just call the doctor instead of the
ambulance).

About an hour later I was continuing the clinic, having been treated and
bandaged when the cat's owner returned. She looked a little worried and
came over towards me. I was getting ready to tell her I was OK when she
said, "Doc, I don't have anything to worry about with all that blood, do
I?" I told her, "I sure hope not!"
 

Copyright, TierCom, Inc., P.O. Box 476, Cobbs Creek, VA 23035. Opinions are solely those of Michael Richards, DVM