The effect of energy intake prior to oestrus and subsequent to mating on ovulation rate and litter size at birth in gilts : a thesis presented in partial fulfilment of the requirements for the degree of Master in Animal Science at Massey University

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'I'HE EFFECT Or' ^ENERGY

INTAI\.E

^PRIOR '1'0 OES'l'RUS AND SUBSEQUENT TO

MATING

ON OVULATION RATE Al'ill ^LITTER SIZE AT BIRTH IN GILTS

A thesis prese nted in partial fulfilment of the requirements for the degree of Master in Animal Science at

�!s.soe y University

LE-NGOC

CHI.-MINH 1 973

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A B S T

R A C T --

o--

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The objective of this investigation was to exam

ine the effect of flushing for about eleven days prior to service and plane of nutrition during the first month of

pregnancy on the reproductive performance of gilts.

Additional observations were also made on plasma proges

terone levels during early and late pregnancy and body temperature changes during the o estrous cycle and late pregnancy in gilts.

A flushing ration of 3.6 kg per day representing 1 0 .80 Meal of digestible energy, given to gilts at about 5th oestrus (270 days old and 1 1 5 kg body weight ) did not make any significant difference in ovulation rate or litter size at birth from the control gil ts under similar physio-

logical conditions, receiving 1 . 8 kg of the same feed per dayo It was thought that the gilts were mated late in their reproductive life and their body conditions might partly explain the discrepancy between the present study and others.

In contrast, high plane of nutrition during the

first month of pregnancy significantly increased litter

size and weight at birth. Average birth weight of pigs,

however, was unaffected. No interaction between pre- and

post-mating feeding levels could be found on any of these

three characteristics.

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Plasma progesterone levels increased signi�icantly

�rom Day

3

^{to Day} 1

5

and declined gradually �rom Day 1 00 through Day 110 ^to 112 o� pregnancy. The e��ect of

feeding treatments

(

pre- and post-mating

)

was not signi�:i.-·

cant except at stage

5 (Day 110 o� pregnancy). Mummi�ied

�oetuses were signi�icantly correlated with progestero ne levels at the last two stages

(

^Day ¹¹⁰ ^and¹¹² ^o�

pregnancy

)

^.

Rectal temperatures o� gilts increased s ignifi

cantly from Day 2 ^{to Day}

6

then tailed o�� until Day 10 ^o�

the oestrous cycle.

(

^Day ^0: day o� oestrus

)

^. During late pregnancy, rectal temperatures dropped signi�icantly �rom Day

6

^{to Day}

3

prior to �arrowing day. However, due to big daily variations and the unreliability o� the measure

ment, temperature changes were not suggested as a diagnosis method of ovulation and parturition.

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(

^iv

)

The author is specially indebted to his supervisors9 Mr J.R. Carr9 Drs M.F. iVIcDonald9 I.J.

Shearer and J.L. Adam for their invaluable guidance and assistant in experimental work and advice in the

preparation of this manuscript.

Special thanks are due to Mr J.C. Mann for his timely help in the correction of this manuscript;

to Mrs Jepson for the typing of this thesis.

Gratitude is extended to Profs. D.S. Flux, R.J. Townsley, A.L. Rae and Hr D. Duganzich for advice in statistical analysis; to Messrs G. Pearson, K.

Armstrong9 A. Quynh and T.Q. Dat for the care of animals and assistance in blood collection procedure.

Gratitude acYJlOWledgment is made to Dr I .J·.

Shearer, Jennifer, r11argaret and laboratory staffs at Ruat:ura Agricultural Research Station in performing the progesterone assay; to Dr B.E. Goulden, Mr J.A.

Cadwallader and staff at Massey Veterinary Clinical Science in conducting the laparotomy.

The author is also grateful to the staff of the library for their co-operation in obtaining references, and to Colombo Plan for financial assistance for his

study.

All figures were p rocessed by the Central Photo graphic Unit, Massey University.

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TABL:�

OF CON'l'El\TS

n::·J:',\.ODUCT

_ION

I ^Li

tera.ture rovic:r II Methods and matcrir�ls

III

Results

IV

Discussion

V

Co:1clusion

CI-iAPTER 2

I;FFECT

OF PUJTE

OF NU.L'RTi'Im\T DURilTG

THE F

^I

R

_S

T

i'IOl'TH Cl"

P:R.EGN)J.l"CY

01.� FJ.RRC'·�-III�G

RESULTS

I

Li

tcrE� ture re

v ievr

II i�Iethods d1ld m2-torials

III

Hosul

_ts

IV

Discussion

V Conclusion

CI-l!'>.PTER 3

PI.ASiriA

PROGESTERO]TE

_LEVELS

DURErG EARLY

_AND

I,ATE

PREG�>lWY I Introduction

II

L i t

_er_at

u

_r_e

review

III M e^th^ods

and materials

IV

Results

V

Discussion VI Conclusion

Psge

1

3 1 3 9 17 33

35 41 43 45 54

57 55

62

71 67

8 5

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( v i )

CHAPTER

L�

RECTAL TENPE.l�ATURE DURIHG OESTROUS CYCLES .AND LATE PREG!.TANC

Y

IN GILTS Po.

e

I Li tcrc..turc review 87

II Method s and materials 90

III Rcsul ts 92

IV Discu s s i on 94

V Conclu sion 99

GENERP� CONCLUSION 1 00

_4PPEl\fDICE S 1 03

REFERENCES 1 1 7

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LIST OF TABLES

Table Number i ⁰

f) <.... .

3 .

4 . 5.

7.

Effect of flushing prior to servi ce on ovulation rate and litter size at birth

Litter size9 weight

(k:J

^at birth and average b irth we ight

(t:g)

of :pigs from

gil ts :f'ed on high and low plane of nutrition during the first month of pregnancy

Progesterone levels in peripheral blood plasma of smvs at their minimum and maximum values dur ing early pregn.ancy or dm"ing the oestrous cycle

Plasma progesterone levels

(

ⁿ

g/

^ml

)

^at

six stages of blood coll ection i'tlcan values of progesterone l evels

(

ⁿ

g/

^r:1l

)

fro,n gil ts of each main gi•oups 2t six stages of blood coll ection0 Mean of rectal temperature

(

0

C)

^during oestrous cycle and last fifteen days of pregnancy

Analysis of v2riance of rectal temper

atures during oestrous c ycle and ^last :fifteen days of pregnancy

Page

1 5

44

59 68

70 7 2

93

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F igur e Numb e r

1

^•

Layout of th e hous i ng ar en u s ed in the exp eriment

2 ⁰

S tandard curv e prep ared :from CBG--H3B wi th human pla sma

3 . P eriph e ral b l o od plasma p rog e s t er one c oncentrat ion i n g i l t s during early and l at e pr egnancy

4. Aver ag e da i l y r ec t al t empera ture s of 1 6 gi l t s dur i ng o e s t r ous cycle

5.

Av erag e dai l y t empera ture of 1 6 g i l t s dur i ng the l a s t 15 days of p r egnm1cy

Pla t e Numb er 1

⁰

2.

Exp erimental hou s e

In s i de

the

exp erimental hous e

Individual p en

4 . Re c en tly :fo rmed c orpora lut ea of gilt s a t l apnro tomy

( v i i i )

b e tw e en page s

9 - 1 0 62 - 63

69 - 70 93 - 94 93 - 94

9 - 1 0

1 1 - 1 2