663. Seasonal Changes in Plasma Concentrations of LH in the Lesser Snow. Goose (Anser caerulescens caerulescens). R. R. CAMPBELL,. S. A. ASHTON1,.
BIOLOGY
OF
REPRODUCTION
18,
Seasonal the R.
R.
66 3-668
Changes
Lesser
Snow
CAMPBELL,
in Plasma
Goose
S. A.
Department
(1978)
(Anser
ASHTON1,
of Zoology,
Concentrations
B. K.
University
of LH in
caerulescens
caerulescens)
FOLLET1
J. F. LEATHERLAND
and
of Guelph,
Guelph,
Ontario,
Canada
ABSTRACT
Highest (Anser females
levels
of
plasma
caerulescens were evident
LH
concentrations were evident June; these
caerulescens) in May and
gonads are mature. early stages of fall LH concentrations
in adult in April high values
A second increase in LH was migration. Goslings (and yearlings) although there was no concomitant
INTRODUCTION
This
study
lating
reports
levels
(Anser
of
caerulescens
stages
of
its
years
of
age)
North
life
arctic of
the
vicinity
the
wintering
United
of
the
the
to
nesting
the
the
same
old
birds
do
mature
establish
and
subsequent
birds
pair
The
lay,
may
crine ments
pair-bonds
that
the
for
be
related
stimulation seasonal
the
to of
delay
in
understood
a the
delayed
changes
onset
November 4, 1977. June 2, 1977. of Zoology, Bangor, U.K.
in
the
breeding although
gonads;
of
thus LH
University
endo-
measurein
avian
a
into
this
al.,
1973;
et
al.,
1975;
(e.g.
Follett, et
al.,
al.,
1974). of is
(Follett, has
al.,
Wilson
been
ducks
and
Haase Follett,
Mallard
studies LU
hor-
Nicholls
and
Herring
activity.
1976;
in
pigeon/dove, 1976;
upon
also in
Quail,
between
gonadal
FSU
Japanese
These
dependent
gens
domesticated
1976;
correlation
permitted
changes
of
finches,
Mattocks
has
cyclic
1976;
various
et
radioimmunoassay
1972)
number
species
et
rulescens)
third of
of
insight
Ducks,
Gull,
Scanes
have
shown
levels
and
Gametogenesis both
Brown
FSU and
implicated (Balthazart
in
and
Follett, in and
a the
andro1977).
display
be-
Hendrick,
AND
METHODS
birds
of
College
of
of Birds
and
Collection
663
Lesser Snow Geese of both blue and
of Samples
caerulescens caephases were collected by shooting, cannon netting and (in moulting birds) by net corrals at several seasonal stages over a 2-year-period (1974-75). Wintering and premigratory spring collections were made at Sabine National Wildlife Refuge, Hackberry, Louisiana by cannon netting. Spring migration collections were made in the vicinity of Pilot Mound, Manitoba and at La Perouse Bay, Manitoba by shotgun. Collections during the 1st and 3rd week of incubation were made from the La Perouse colony by shotgun; nesting histories for these birds were known since they formed part of the study of Dr. F. Cooke and associates, Queens University, Ontario. Collections during moult were made by driving flightless birds into net corrals and killing by decapitation. Fall migration collections were made at Moosonee, Ontario and Squaw Creek, Missouri, by shotgun. Dates and sites of collection are shown in Table 1.
2-
behaviour.
onset
in
MATERIALS
males
majority
is not
levels
Wild
the
nesting
and
Capture
of
older
during
the
2-year-
numbers
with
demonstrate
yearlings
Accepted Received ‘Department North Wales,
migration.
form
pair
seasons
by
of
spring
is only
seasonal
or
the
when
1976).
adults.
the
of
havior
pairing
small
It
not
of
although may
and
the
study
times
exposed
gonads
usually
nests.
reasons
activity
as
in
not
females
and
are
a
the
birds
gonads
of
et al.,
clear
mi-
do
they
demonstrate
late
do
to
year-old
The
(yearlings)
not
in
leave and
Geese
in adult
during the of plasma
an
(Follet
et
migrations
May.
that
The
birds begin
mid
fact
behavior.
These
April
major
photostimulation
yearlings
nesting
or of
birds
despite
The
in
1-year-old
mature
March
times
provide
LH
Donham
Coast
They
the
development
1974;
eastern
principally
Texas.
a series
summer
Gulf
may
Snow
levels
collected elevation
avian
wild
they
the
the
and in
in
the
of
States,
Louisiana range
reach
where
with
for mone
of
photoperiod
goslings to
(3
areas
June long
migrate
northwards
to
and
and
different geese
ages
The
Goose
subarctic
Following
adults
of
at
extremely
southern
grate
or
May
an
population
the
Snow
well
lesser
highest
phenomenon.
in circu-
snow
the
20h/day).
the
Lesser
Adult in
in to
(approaching
it
cycle. breed
exposed
moult,
the
changes
caerulescens)
America
are
in
the
male
while
found in adult females showed a similar summer increase in gonad size.
different
on
LH
(3-year-old) and May correlate
(Anser white
664
CAMPBELL
ET
AL.
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LU
LH
GOSUNGS
IN THE
LESSER
VEASUAGS
0
S
GOOSE
1 mg ml
#{149} I
SNOW
LHRF
0.5
Samples
ml
after
Statistical
SOY
DEC
FIG. 1. Seasonal variations in plasma LH levels in Snow Goose goslings during their first year of life. Embryos are from 18 days of incubation to hatch. The data are expressed as mean ± standard error of mean. Groups containing less than 3 birds were omitted from the analysis of variance. The individual values of these samples are as follows (ng/ml): males September 0.38, 0.47; March 2.10, 1.86; May 2.60, 4.60; June 4.68. Females April 1.24, 2.46; July 0.84, 0.76. Goslings were considered to be yearlings by June of the year following hatch.
blood
2 mg
LHRF
ml)
were
(2
administration
(in
0.5
taken
at
Analysis were compared Predetermined least significance
RESULTS No
significant
tween
the
thus
differences
different
collections
the
made
2 years
Plasma Goslings
are
LH 0.99
in
or July
female (1.45
respectively), goslings
different
from
the
in
perivitelline mean
plasma was
higher
and
plasma
was than
hatched
0.73
in
± the
±
either killed
0.78
ng/ml,
value
significantly the
3.21
goslings
1.06
only
in
times
1)
The
was that
same
in
newly ±
beand
in (Fig.
although
female
the
embryonic which
found
collection
together.
detectable.
in
ng/ml
male
at
LH not
level
of
considered
LH Concentrations and Yearlings
was
were
years
lmmunoreactive
In all cases the birds were killed between 1000 h and 1500 h and blood was immediately collected from the carotid artery into heparinized Vacutainer tubes. The tubes were kept on ice until they could be centrifuged and the plasma stored at -35#{176} until it was assayed. Plasma for LH assay was treated with a small quantity (