Seasonal Changes in Plasma Concentrations of LH in the Lesser ...

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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.

SO C

so C LU

O

v

.9

C C 0 0 C

0 .00

LULU LU

0

C

0

0 0

0 0

so

LU

so

0

o.

C

(4 “

0 0

(4

.0

.0

.0

U

Cl)

Cd)

Cl)

LU LU

Z

0 0

so C 0 0

.0

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C/)

LU)

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C o 0 0 C 4

U

(4 #{149}.0

0

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.OLU o LU

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.

0

‘B

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so

(40

‘0(4

C

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so

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v ,4(4

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.

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I.C

=Q

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C,,.,4

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C

=

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0.

‘0

a LU

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0 0 O

LU

(4

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z’

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0

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LU LU

LU

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(‘4



0.

LU-...

LU

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,-rn

9

LU

“4

-,0s

LU .0

Cl)

Z

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 (

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