Cat population control; vasectomize dominant males


Kendall, T.R.

California Veterinarian 33(7): 9-12

1979


Animal
Control
Cat
Population
Control:
Vasectomize
Dominant
Males
Thomas
R.
Kendall,
DVM
Sacramento,
California
The
Problem
Mature,
intact
female
cats
(Queens)
are
either
in
heat
or
pregnant
from
January
to
September.
Humane
shelters
and
Public
Animal
Control
facilities
are
besieged
with
unwanted
kittens,
of
which
the
majority
are
destroyed.
In
1978
in
Sacramento
County
approximately
15,000
cats
were
euthanized.
The
majority
was
younger
than
six
months."
In
1973,
18
million
animals
were
impounded
in
the
United
States
at
a
cost
of
$125,000,000.
Of
these,
80-90%
were
euthanized.
16
Cats
pose
a
unique
reproduction
problem.
Being
polyestrus,
53
mature
Queens
are
difficult
to
keep
from
sexual
activity.
Schneider
and
Vaida
(1975)
give
some
interesting
statistical
data
on
controlling
feline
reproduction.
They
made
a
5%
random
sample
survey
of
households
in
Alameda
and
Contra
Costa
counties
in
1970
and
found
that
between
1960-1970,
the
feline
population
increased
by
66%.
52
Of
the
total
estimated
feline
population
of
about
151,000,
64.6%
of
all
Queens
were
neutered.
The
age
of
highest
reproductive
capacity
in
Queens
is
between
1
and
3
years.
74.4%
of
all
feline
litters
are
born
during
this
period.
Although
spaying
Queens
has
been
advocated
by
many
as
a
means
of
controlling
excess
feline
populations,
Schneider
(1975)
concludes
that
excess
kittens
could
be
expected
unless
75-80%
of
all
Queens
are
neutered.
So,
unless
we
have
75%
spayed
Queens,
we
aren't
making
any
progress
in
population
control.
He
found
that
even
if
66%
of
Queens
and
52%
of
the
males
were
neutered,
the
production
of
kittens
was
still
almost
twice
the
number
that
could
be
placed
in
homes.
For
example,
by
1975,
75%
of
the
Queens
in
Alameda
and
Contra
Costa
Counties
had
been
spayed,
yet
in
1975
there
were
still
more
than
12,000
cats
being
over-
produced
and
subsequently
euthanized.
51
Spaying
and
neutering
alone,
under
present
conditions,
does
not
totally
solve
the
problem.
Schneider
also
found
that
66%
of
Queens
entering
a
household
as
a
pet
are
no
longer
in
that
household
after
3
years.
Only
30%
are
given
away
by
the
owner.
What
happens
to
these
cats
that
nobody
owns?
Observations
of
the
Reproductive
Cycle
in
Cats
A
Queen
is
seasonally
polyestrus
and
is
a
spontaneous
ovulator,
in
that
she
does
not
shed
her
eggs
from
the
ovary
unless
her
reproductive
tract
is
properly
stimulated
by
the
Tom
during
mating
or
a
similar
mechanical
stimulus.'
39 22
18
(Tom
refers
to
an
intact,
sexually
mature
male
cat.)
Following
this
reflex-neuronal
stimulation,
the
eggs
are
shed
from
the
ovary
within
25-27
hours.'
2
Paape,
et
al
(1975)
found
that,
in
the
absence
of
mating,
the
Queen
does
not
ovulate
and
experiences
a
series
of
heats
at
approximately
18-day
intervals
during
California
Veterinarian
/
July
1979
9
Animal
Control
the
breeding
season.
They
found
the
heat
lasts
an
average
of
7
days,
with
a
range
of
4
to
13
days
and
mating
can
occur
on
any
day
of
heat,
but
matings
are
more
likely
to
occur
on
or
about
the
third
day.
Hart
and
Voith
(1977)
came
to
similar
conclusions.
The
anestrus
female
will
not
tolerate
the
mating
attempts
of
a
Tom
more
than
momentarily
and
invariably
will
free
herself
from
the
attempted
mount-
ing
by
a
male
with
considerable
vigor,
spitting,
scratching,
and
biting.
36
Rape
by
the
male
does
not
occur
in
cats?'
The
experienced
Tom
awaits
the
de-
velopment
of
full
sexual
receptivity
(es-
trus)
while
younger
males
make
sev-
eral
premature
mounting
attempts
and
sometimes
are
bitten
and
scratched
severely.
Michael
(1961)
found
that
the
estrus
female
is
completely
receptive
to
the
Tom's
coital
efforts
and
doesn't
exhibit
aggressive
refusal.
The
time
between
mounting
and
intromission
rarely
exceeds
four
minutes.
When
in-
tromission
occurs,
the
female
emits
a
loud,
piercing
cry
and
within
5-15
sec-
onds
frees
herself,
spitting
and
scratching.
Preliminary
experiments
now
in
progress
indicate
that
some
male
cats
distinguish
females
in
heat
without
attempting
to
mount,
but
it
is
not
known
yet
whether
olfaction
is
needed
for
discrimination.
2
If
mating
is
fertile,
the
ensuing
pregnancy
lasts
about
64
days,with
a
range
of
58-69.
43
Jemmett
and
Evans
(1977)
found
Queens
reached
sexual
maturity
from
9-10
months.
They
also
found
Queens
had
an
infertile
estrus
within
7-10
days
of
Queening
(birth
of
kittens),
but
may
have
a
fertile
estrus
before
weaning
her
kittens,
thus
making
it
possible
to
have
3
litters
per
breeding
season.
This
shows
there
is
no
validity
in
the
old
wives
tale
that
"as
long
as
she's
nurs-
ing,
she
can't
get
pregnant
again."
31
Michael
(1961)
found,
as
did
Bard
(1936),
no
vestige
of
estrus
response
in
a
series
of
400
mating
tests
conducted
with
30
spayed
females,
and
mating
with
intromission
never
occurred.
Paape
et
al
(1975),
and
Foster
and
Hisan
(1935),
found
mating
with
a
sterile
(vasectomized)
Tom
or
manual
stimulation
with
a
sterile
glass
rod,
will
induce
false
pregnancy
in
the
Queen
which
lasts
about
41
days.
The
maximum
number
of
pseudo-
pregnancies
a
Queen
can
undergo
in
one
breeding
season
(January
to
Sep-
tember)
was
not
fully
tested,
but
it
ap-
pears
that
4-5
may
be
possible.
39
Based
on
this
data,
it
would
seem
pos-
sible
to
keep
an
intact,
potentially
fer-
tile
Queen
"out
of
the
kitten
business"
for
the
entire
breeding
season
by
being
bred
by
a
vasectomized
Tom
every
time
she
came
into
heat.
Dr.
Benjamin
Hart
at
the
University
of
California,
School
of
Veterinary
Medi-
cine
Cat
Colony,
observed
that
one
Tom
can
breed
up
to
five
females
com-
ing
into
heat
over
a
two-day
period.
21
Hart
and
Voiths'
(1977)
present
work
indicates
that
a
sexually
mature
Tom
can
maintain
normal
copulatory
activ-
ity
with
less
than
half
of
the
normal
circulating
level
of
testosterone.
With
castration,
testosterone
levels
drop
to
almost
undetectable
levels
within
6
hours
of
the
surgery.
46
45
Hart
and
Bar-
rett
(1973)
found
that
the
sexual
ag-
gression
occurring
between
male
cats
is
androgen
dependent,
in
that
88%
of
the
fighting
declined
following
castra-
tion.
Since
Toms
form
a
sexual
domi-
nance
heirarchy
based
on
their
ag-
gressive
performance,
one
would
need
to
castrate
an
extremely
high
percentage
of
the male
population
to
make
a
dent
in
the
excess
kitten
popu-
lation.
Each
time
a
dominant
Tom
in
a
neighborhood
is
castrated,
the
next-
in-line
Tom
moves
in
to
take
over.
However,
by
vasectomizing
the
domi-
nant
Toms,
these
Toms
will
prevent
submissive,
intact
Toms
from
in-
seminating
non-spayed
Queens.
In-
creased
sexual
aggressiveness
can
be
induced
by
long-acting
testo-
sterone
implants
in
a
vasectomized
male
as
one
additional
help
in
main-
taining
or
establishng
sexual
domi-
nance
of
a
Tom
in
a
neighborhood.
Vasectomy,
which
by
definition,
means
to
remove
a
portion
of
the
Duc-
tus
Deferens,'
4
does
not
effect
testo-
sterone
levels
as
long
as
the
spermatic
artery,
which
supplies
the
testes,
is
kept
intact.
56
41
While
castration
of
a
male
cat
seems
to
be
the
solution
to
roaming,
spraying
of
urine,
and fight-
ing
in
90%
of
the
cases,
vasectomies
are
a
tool
for
population
control
only.
25
48
Social
Behavior
in
Tomcats
Laundre
(1977),
Lorens
and
Ley-
hausen
(1973),
Cole
and
Shafer
(1966),
Leyhausen
(1965),
Baron,
et
al
(1957),
Winslow
(1941),
and
Winslow
(1938)
clearly
established
a
domi-
nance
hierarchy
exists
in
laboratory
and
free-roaming
feral
cats.
Schjelde
-
rup-Ebbe
(1922)
was
the
first
to
rec-
ognize
an
"absolute
hierarchy"
in
hens,
that
now
has
come
to
be
known
as
the
famous
"peck
order."
Presently,
researchers
disagree
on
whether
a
similar
absolute
hierarchy
exists
among
cats.
All
agree
that
there
is
a
dominant
male
at
the
top.
Cole
and
Shafer
(1966)
concluded
that
dominant-submissive
relations
are
far
less
complex
and
more
predictable
in
the
cat
than,
for
example,
in
the
mon-
key.
They
felt,
as
did
Hart
(1974),
that
recognition
of
overt
behavior
serves
as
an
important
cue
for
the
development
of
dominance-subordinance
relation-
ships
and
is
more
important
as
ex-
pression
of
threat
rather
than
actual
aggression
after
dominance
has
been
established.
Both
Cole
and
Shafer
(1966),
and
Baron,
et
al
(1957),
found
almost
total
absence
of
retaliatory
be-
havior
in
response
to
an
aggressive
act.
Leyhausen
(1973),
who
has
studied
free-roaming
cats
extensively,
says
a
locality,
priority
dependent
hierarchy
exists
for
food
gathering
and
socialization,
but
an
absolute
hierar-
chy
exists
in
relation
to
sexual
prowess
such
as
exists
in
herding
animals.
He
further
elaborates
on
what
he
calls
a
"Tom
Brotherhood"
that
exists
as
semi-cooperation
between
dominant
Toms
that
roam
in
small
packs
of
2-3
during
.
the
mating
season.
This
would
correlate
with
the
findings
of
Cole
and
Shafer
(1966)
in
a
laboratory
environ-
ment
that
the
dominant
cat
of
any
given
group
was
able
to
successfully
dominate
the
subordinate
members
of
any
other
group.
It
is
these
"top
cats"
that,
according
to
Leyhausen,
are
probably
responsible
for
breeding
nearly
all
Queens
in
a
several
block
geographical
area.
Carol
Haspel,
in
unpublished
data
on
free-roaming
10
California
Veterinarian
/
July
1979
cats
in
New
York
estimates
the
territory
of
a
feral
Tom
as
one
city
block.
27
Using
random
surveys
of
cat
population
densities
and
geographical
data
about
human
occupancy,
the
number
of
dominant
cats
that
need
to
be
vas-
ectomized
in
a
given
area
could
be
determined.
The
results
within
6
months
to
a
year
if
less
kittens
were
euthanized
and
a
subsequent
in-
crease
in
the
mean
age
of
cats
in
the
area
could
be
compared.
Most
wild
felids
lead
solitary
lives,"
24
26
30
44
54
with
the
exception
of
the
lion.
The
domestic
cat
seems
to
favor
a
solitary
existence
in
the
feral
state,
but
will
live
on
a
communal
basis
to
utilize
a
common
food
source.
32
33
34
Domestic
and
wild
felines
have
de-
veloped
territorial
behavior
to
reduce
intraspecies
communications.
3
15
35
54
This
"territory"
is
actually
the
paths
be-
tween
points
of
food
gathering,
sleep-
ing,
mating,
and
fighting.
33
34
35
These
paths
are
marked
with
urine,
feces,
and
scratching.3
54
Because
of
urban
crowding,
domestic
cats
and
free-roaming
feral
cats
rely
on
visual
avoidance
and
threat
behavior.
23
25
Michael
(1961),
Hart
(1977),
and
Hediger
(1950)
found
the
male
cat
will
normally
not
mate
in
strange
surround-
ings,
but
once
settled
and
established
in
its
territory,
will
show
mounting
activ-
ity
towards
every
estrus
Queen
pre-
sented.
This
fact
is
significant
if
do-
minant
males
are
to
be
trapped,
vas-
ectomized
and
released.
They
should
be
released
in
the
same
spot
they
are
trapped.
Vasectomy—The
Procedure
Robinson,
et
al
(1'975)
suggested
using
vasectomies
in
adult
male
lions
as
a
method
of
birth
control
because
of
the
over-population
problem
in
captive
lions.
Ree
and
Tennant
(1975)
de-
scribed
a
surgical
procedure
for
Afri-
can
lions.
Burke
(1977)
suggests
using
vasectomies
for
fertility
control
in
the
cat.
Pineda
(1976)
and
Clinton
(1972)
suggested
its
use
in
dogs.
Pineda
(1978),
Pineda
(1977),
and
Freeman
and
Coffey
(1973)
suggest
a
chemical
vasectomy
in
dogs
by
inject-
ing
sclerosing
agents
into
the
lumen
of
the
Vas
Deferens.
This
procedure,
if
possible
in
cats,
would
only
apply
to
adult
Toms.
A
simple
surgical
vasec-
tomy
for
Toms
has
been
described
by
Norsworth
(1975)
and
Herron
and
Her-
ron
(1972)
to
cause
minimal
surgical
trauma.
Although
they
described
the
surgery
for
the
adult
Tom,
Dr.
Gourly
at
the
University
of
California
School
of
Veterinary
Medicine,
says
such
a
pro-
cedure
could
be
developed
for
8-12-
week-old
kittens.
2
°
Seager
and
Wildt
(1977)
describe
a
five-minute
abdominal
vasectomy
via
an
operating
laparoscope.
Dr.
Wildt,
of
Purina
Research,
said
several
young
kittens
were
vasectomized
in
June,
1978,
at
the
Purina
Research
Center
and
he
will
follow
up
the
results
in
June,
1979.
57
Dr.
Wildt
says
he
has
not
ob-
served
any
reduction
in
sexual
ag-
gressiveness
in
Toms
he
has
vasec-
tomized
or
8-12-week-old
kittens
who
reached
sexual
maturity
later.
57
The
laparoscope
would
provide
the
easiest
procedure
in
young
kittens.
The
spermatic
artery
could
be
entirely
avoided
by
using
this
abdominal
ap-
proach.
Destruction
of
the
deferential
artery,
which
lies
along
the
vas
defe-
rens,
does not
seem
to
pose
a
prob-
lem,
according
to
Dr.
Wildt,
Since
there
is
anastomosis
with
the
sperma-
tic
artery,
the
major
blood
supply
to
the
testicles,
and
collateral
circulation
de-
velops.
57
Herron
and
Herron
(1972)
pointed
out
in
their
procedure
on
adult
Toms
that
the
integrity
of
the
deferen-
tial
artery
should
be
maintained.
38
Outline
of
a
Vasectomy
Program
A
vasectomy
program
for
dominant
Toms
should
be
twofold.
1.
All
male
kittens
publicly
adopted
from
humane
societies
and
shelters,
and
municipal
animal
control
facilities
should
be
vas-
ectomized
prior
to
adoption.
In
California,
we
need
to
change
the
California
Food
and
Agricultural
Code
#31255,
Division
14.5
on
regulation
of
new
cats
to
cover
vasectomies
rather
than
neutering
males.
Funds
would
be
collected
in
advance
of
adoption.
2.
Free-roaming
feral
Toms
could
be
trapped
and
excess
monies
collected
under
Code
#31255
from
deposits
not
redeemed
(presently
running
over
50%
in
Sacramento
County,
17
the
city
of
Palo
Alto,"
and
most
other
cities
in
California)
could
cover
the
cost
to
vas-
ectomize
these
cats.
All
vasectomized
cats,
both
young
and
old,
should
be
identified
by
a
tattoo
number.
These
numbers
would
be
coded
with
a
com-
puter
card
giving
location,
age,
date
of
vasectomy,
veterinarian
performing
the
surgery,
and
sponsor
of
the
re-
leased
Tom.
Population
statistics
could
then
be
used
to
verify
the
effec-
tiveness
of
the
program.
Summary
Schneider's
(1975)
studies
indicate
75-80%
of
the
feline
population
must
be
spayed
or
neutered
to
bring
the
supply
of
kittens
in
balance
with
de-
mand
by
the
human
population.
Mass
spaying
and
neutering
of
cats
has
so
far
proven
ineffective
in
causing
this
balance
to
occur
because
of
the
tre-
mendous
turnover
and
productivity
of
feline
populations.
Vasectomizing
dominant
male
cats
as
a
means
of
animal
population
control
provides
a
fresh
solution
to
an
un-
solved
problem.
With
cooperation
of
humane
groups,
veterinarians,
gov-
ernment
agencies,
and
municipal
animal
control
agencies,
we
can
reach
a
balanced
population
in
cats.
References
and
Bibliography
1.
Allen,
R.
D.,
and
Westbrook
(Editors)
(1978)
The
Handbook
of
Animal
Wel-
fare:
Diomedical,
Psychological
and
Ecological
Aspects.
New
York
Gar-
land
Publishing
Inc.
A.
Faulkner,
L.
C.,
and
Pineda,
M.
H.
Diomedical
Considerations
7:
pp.
1-53.
2.
Aronson,
L.
R.;
Cooper,
M.
L.
(1974)
Olfactory
deprivation
and
mating
be-
havior
in
sexually
experienced
male
cats.
Behavior,
Biol.,
11:
pp.
459-480.
3.
Bailey,
T.
N.
(1974)
Social
Organiza-
tion
in
a
Bobcat
Population,
J.
Wildl.
Mgt.
38
(3):
435-446.
4.
Bard,
P.
(1936).
Oestrual
Behavior
in
Surviving
Decorticate
Cats.
Amer.
J,
Physiol.
116:
pp.
4-5.
5.
Baron,
A.;
Stewart,
C.N.;
and
Waren,
J.
M.
(1957)
Patterns
of
Social
Interac-
tions
in
Cats.
(Felis
Domestica)
Be-
havior
11
(1),
55-66.
6.
Beach,
F.
A.
(1970)
Coital
Behavior.
VIII.
Social
Affinity,
Dominance,
and
Sexual
Preference
in
the
Bitch.
Be-
havior
36:
131-148.
7.
Beach,
F.
A.,
and
Leboeuf
(1967)
Coi-
tal
Behavior
in
Dogs.
I,
Preferential
Mating
in
the
Bitch.
California
Veterinarian
I
July
1979
11
8.
Burke,
T.
J.
(1977)
Fertility
Control
Be-
havior
in
the
Cat.
Vet.
Clinics
in
North
Amer.
7
(4):
699-703.
9.
Clinton,
R.
L.;
Stump,
F.
J.;
Wiggers,
K,
L.,
(1972)
Canine
Vasectomy:
A
Mod-
ern
Solution
to
an
Age
Old
Problem.
Vet.
Med.
Small
Anim.
Clinic.
Oct:
1097-1099.
10.
Cole,
D.
D.,
and
Shafer,
J.
M.
(1966)
A
Study
of
Social
Dominance
in
Cats.
Behavior,
27
(I):
39-53.
11.
California
Veterinary
Medical
Associa-
tion
Animal
Population
Control
Com-
mittee
Minutes.
June
14,
1978,
pp.
1-8.
12.
Dawson,
A.
B.;
Friedgoud,
H.
B.
(1940)
The
Time
and
Sequence
of
Preovulat-
ory
Changes
in
the
Cat
Ovary
After
Mating
or
Mechanical
Stimulation
of
the
Cervix
Uterus.
Anat.
Rec.
76:
411-
429.
13.
Djerass,
C.,
Israel,
and
Jochle.
(1973)
Planned
Parenthood
for
Pets?
Bull.
Atomic
sc.
1:10-19.
14.
Dorlands
Illustrated
Medical
Dictio-
nary,
24th
Edition,
W.
B.
Sanders
Co.
1965.
15.
Eibl-Eibesfeldt,
I.
(1970)
Ethology
of
the
Biology
of
Behavior,
pp.
175-180,
269-362.
New
York:
Holt,
Rinehart,
and
Winston.
16.
Faulkner,
L.
Cm
(1975)
Dimensions
of
the
Pet
Population
Problem.
J.
Ameri-
can
Vet.
Med.
(March
1,
1975):
477-
478.
17.
Flynn,
Charles
(Feb.
1979)
Personal
Communication.
18.
Foster,
M.
A.,
and
Hisaw,
F.
L.
(1935)
Experimental
Ovulation
and
the
Re-
sulting
Pseudo
Pregnancy
in
Anoes-
trus
Cats.
Anat.
Rec.
62
(1):
75-90.
19.
Freeman,
C.,
and
Coffey,
D.
S.
(1973)
Sterility
in
Male
Animals
by
Injection of
Chemical
Agenas
Into
the
Vas
Defe-
rens.
Fertility
and
Sterility
24
(11):
884-890.
20.
Gourley,
Gary
(1979)
Feb.
1979
Per-
sonal
Communications.
21.
Hart,
B.
(1979)
Feb.
27,
1979
Personal
Communications.
22.
Hart,
B.
L.,
Voith,
V.
L.
(1977)
Feline
Behavior
-
Sexual
Behavior
and
Breeding
Problems
in
Cats.
Feline
Practice.
Jan.:
9-12.
23.
Hart,
B.
L.
(1975)
Feline
Practice
-
Behavioral
Patterns
Related
to
Territo-
riality
and
Social
Communication.
Jan.-Feb.:
12-14.
24.
Hart,
B.
L.
(1974)
Feline
Behavior
--
Social
Interaction
in
Cats.
May-June:
12-20.
25.
Hart,
B.
L.;
Barrett,
R.
E.
(1973)
Effects
of
Castration
on
Fighting,
Roaming,
and
Urine
Spraying
in
Adult
Male
Cats.
J.
Amer.
Vet.
Med.
Aug.
1,
1973.
290-
293.
26.
Hart,
B.
L.
(1972)
Feline
Behavior
-
Gonadal
Hormones
and
Behavior
of
the
Male
Cat.
Feline
Practice.
May-
June
7-8.
27.
Haspel,
Cerro!
(1979)
March
1,
1979,
Personal
Communications.
28.
Hediger,
H.
(1950)
"Wild
Animals
in
Captivity"
Publ.
Butterworths,
London.
29.
Herron,
M.
A.;
Herron,
M.
R.
(1972)
Vasectomy
in
the
Cat.
Modern
Veteri-
nary
Practice
53
(6):
41-43.
30.
Hornocker,
M.
G.
(1969)
Winter
Ter-
ritoriality
in
Mountain
Lions.
J.
Wildlife
Mgt.
33
(3):
457-464.
31.
Jemmett,
J.
E.,
and
Evans,
J.
M.
(1977)
A
Survey
of
Sexual
Behavior
and
Re-
production
of
Female
Cats.
J.
Small
Animal
Practice
18,
31-37.
32.
Laundre,
J.
(1977)
The
Daytime
Be-
havior
of
Domestic
Cats
in
a
Free-
Roaming
Population.
Animal
Behavior
25
(4):
990-998.
33.
Leuhausen,
P.
(1965)
The
Communal
Organization
of
Solitary
Mammals.
Symp.
2001.
Soc.
Lond.,
14:
249-263.
34.
Leuhausen,
P.
V.,
and
Wolfe,
R.
(1959)
Das
Revier,
Einer
Hauskatze.
Zeitschrift
Fur
Tierpsuchologue
16
(6):
666-670.
35.
Lorenz,
K.,
and
Leuhausen,
P.
(1973)
"Motivation
of
Human
and
Animal
Be-
havior"
Van
Norstrand
Renhold
Co.,
New
York,
N.Y.
36.
Michael,
R.
P.
(1961)
Observations
Upon
the
Sexual
Behavior
of
the
Domestic
Cat
(Felis
Caths)
Under
Laboratory
Conditions.
Behavior,
18:1-24.
37.
Michael,
R.
P.
(1958)
Sexual
Behavior
and
the
Vaginal
Cycle
in
the
Cat.
Na-
ture
181:567-568.
38.
Norsworth,
G.
D.
(1975)
Alternative
Surgical
Procedures
for
Feline
Birth
Control:
Tubal
Ligation
Vasectomy.
Feline
Practice
Jan.-Feb.:24-27.
39.
Paape,
S.
R.;
Shille,
V.
M.;
Seto,
H.:
and
Stabenfeldt,
G.
H.
(1975)
Luteal
Activity
in
the
Pseudopregnant
Cat.
Biol.
Rep.
13:470-474.
40.
Pineda,
M.
H.
(1978):
Chemical
Vasec-
tomy
in
Dogs.
Canine
Practice
5(2):
34-41,
44-45.
41.
Pineda,
M.
H.;
Reimers,
T.
J.;
Faulkner,
L.
C.,
Hopwood,
M.
L.;
and
Seidel,
G.
J.
(1977)
Azoospermia
in
Dogs
In-
duled
by
Injection
of
Sclerosing
Agents
Into
the
Epididymides.
Am.
J.
Vet.
Res.
38:
831-838.
42.
Pineda,
M.
H.,
Reimers,
T.
J.;
Faulkner,
L.
C.
(1976)
Disappearance
of
Sper-
matozda
From
the
Ejaculates
of
Vas-
ectomized
Dogs.
J.
Amer.
Vet.
Med.
168
(6):
502-503.
43.
Prescott,
C.
W.
(1973)
Reproduction
Patterns
in
the
Domestic
Cat.
Austral.
Vet.
J.
49:126-129.
44.
Reed,
G.
T.;
Tennant, M.
B.
(1975)
Vasectomy
Procedures
for
African
Lions.
Journal
of
Zoo
Animal
Medicine.
6
(2):
15.
45.
Resko,
J.
A.,
and
Phoenix,
C.
H.
(1972)
Sexual
Behavior
and
Testosterone
Concentrations
in
the
Plasma
of
the
Rheusus
Monkey
Before
and
After
Castration.
Endocrinology
91:
499-
503.
46.
Resko,
J.
A.
(1970)
Androgens
in
Sys-
temic
Plasma
of
Male
Guinea
Pigs
Dur-
ing
Development
and
After
Castration
in
Adulthood.
Endocrinology.
86:
1444-1447.
47.
Robinson,
P.
T.;
Sedgwick,
C.
J.:
Lochner,
F.
K.
(1975)
Vasectomy:
So-
lution
to
the
Overpopulation
Problem
in
Captive
Lions?
Veterinary
Medicine;
Small
Animal
Clinic.
Nov.
1975:
pp.
1353-1356.
48.
Rosenblatt,
J.
S.,
and
Aronjon,
L.
R.
(1958)
the
Decline
of
Sexual
Behavior
in
Male
Cats
After
Castration
With
Special
Reference
to
the
Role
of
Prior
Sexual
Experience.
Behavior
12:
285-338.
49.
Schaller,
G.
B.
(1972)
the
Serengeti
Lion:
A
Study
of
Predator-Prey
Rela-
tions,
pp.
355-379.
Chicago:
Univer-
sity
of
Chicago
Press.
50.
Schjelderup-Ebbe,
T.
(1922)
Beitrage
Zur
Sozialpsychologie
des
Haus-
huhns.
Zeitschrif
fur
Psychologie.
(88):
225-252.
51.
Schneider,
R.
(1979)
Feb.
1979
Per-
sonal
Communications.
52.
Schneider,
R.,
and
Vaida,
M.
L.
(1975)
Survey
of
Canine
and
Feline
Popula-
tions:
Alameda
and
Contra
Costa
Counties,
Calif.,
1970.
JAVMA,
166
(5):
481-486.
53.
Schneider,
R.
(1975)
Observations
on
Overpopulation
of
Dogs
and
Cats.
JAVMA,
167
(4):
281-284.
54.
Saunders,
J.
K.
(1963)
Movements
and
Activities
of
the
Lynx
in
New-
foundland.
J.
of
Wildlife
Mgt.
27
(3):
390-400.
55.
Seager,
S.
W.
J.;
Wildt,
D.
E.
(1977)
Laparoscopy:
A
Method
of
Diagnosis
in
Small
Animal
Medicine.
Ralston
Purina
C.
St.
Louis,
Missouri.
56.
Vare,
A.
M.;
Bansal,
P.
C.
(1973)
Changes
in
the
Canine
Testes
After
Bilateral
Vasectomy
an
Experimen-
tal
Study.
Fertility
and
Sterility
24
(10):
793-797.
57.
Wildt,
D.
E.
March
1,
1979
Personal
Communications.
58.
Winslow
(1941)
Patterns
of
Competi-
tive,
Aggressive,
and
Altruistic
Be-
havior
in
the
Cat.
Psycho!,
Bull.
38:
p.
564.
59.
Winslow,
C.
N.
(1938)
Observations
of
Dominance
Subordination
in
Cats.
J.
Genetic
Psychology.
52:
425-428.
12
California
Veterinarian
/
July
1979