5 0. )

(1)

Duration of weaning-oestrus interval and prolificacy ^of

^{sows :}

statistical study ^{of the} ^influence

of various reproductive parameters

M. ÉTIENNE

P. H.

DUÉE

Station de Recherches sur

l’Élevage

^des^Pores,^{T. N. R.}^A.,^{C. N. R.}^7.,

78350

Jouy

^en

Josas

Existence of statistical

relationships

^between^somecriteria of

productivity

ⁱⁿ^sows

(weaning- conception ^interval, prolificacy)

and various

parameters

^measured

during

^the

previous reproduc-

tive

cycle (weight

variation and feed intake of dams and

piglets)

^was

investigated

ⁱⁿ

1 8 3 Lavge

While sows. These

relationships

^wereestimated from the calculation of linear correlation coeffi- cients and

by

establishment of

multiple

linear correlations. The female

population

^studied^was

characterized

by

^a

high proportion

^of

primiparous

^animals

(!3

p.

100 )

^{and small}

weight gains during

^the

reproductive cycle (! 1 6. 7 kg).

The duration of the

weaning-oestrus

interval and

weaning-conception

^interval^were

negati- vely

correlated with the litter order

(- o.2II

^and^{- o.i88,}

respectively

^{for the}^two

intervals)

and

the weight

^{of the}^sows^at

weaning (— 0 . 17 8

^and^--

0.16!). However,

^theshare of the variance

explained by

^these^two

parameters

^wasrestricted

(R I - 0 . 05 ).

^This^was^{also the}^case^for

proli- ficacy

^which^was

only significantly

correlated with the duration of

weaning-oestrus

^or

weaning- conception

^intervals

(r

^!

o.16 4 )

and the variation in the

weight

^{of the}^sows^between

weaning

and

mating (r

^-

0 . 1 88).

^This

weight

^variation^wasrelated to the

weight

^{of the}^sows^at

weaning (r = - 0 . 4S5 )

^and^tothe duration of the

weaning-oestrus

^interval

(r = - 0 . 594 ),

^thesetwo factors

accounting

^for

4 8

p. ¹⁰⁰of the variation.

Although

^this

study

has been made on animals exhibi-

ting

^a^low

productivity,

it demonstrates the existence of

relationships

^between

changes

^{in the}

weight

^{of the}^sowsand their further

performances.

Application ^of weaning

^at

¹² days ⁱⁿ pig ^herds.

Comparative results of the productivity

of

sows over a

period ^{of three} years

A. AUMAITRE

J.

^{LE PAN}

Station de Recherches sur

l’Élevage

^des^Porcs,1. 1V. R A., C. N. R. Z., 78350

Jouy

^en

.rosas

One thousand three hundred and

seventy

^seven^litters

from 5 herds

controlled in the western

part

of France between

January

1972 and October rg!! ^wereweaned

by pairs,

^on^anaverage after either 13.3

days

^of

suckling ( 700 litters)

^or^after

3 8. 3 days (6 77 litters).

^The

5 0. )

Duration of weaning-oestrus interval and prolificacy of

statistical study of the influence

of various reproductive parameters

M. ÉTIENNE

DUÉE

l’Élevage

Jouy

Josas

relationships

productivity

(weaning- conception interval, prolificacy)

parameters

during

previous reproduc-

cycle (weight

piglets)

investigated

1 8 3 Lavge

relationships

by

multiple

population

by

high proportion

primiparous

(!3

100 )

weight gains during

reproductive cycle (! 1 6. 7 kg).

weaning-oestrus

weaning-conception

negati- vely

(- o.2II

respectively

intervals)

the weight

weaning (&mdash; 0 . 17 8

0.16!). However,

explained by

parameters

(R I - 0 . 05 ).

proli- ficacy

only significantly

weaning-oestrus

weaning- conception

(r

o.16 4 )

weight

weaning

mating (r

0 . 1 88).

weight

weight

weaning (r = - 0 . 4S5 )

weaning-oestrus

(r = - 0 . 594 ),

accounting

4 8

Although

study

ting

productivity,

relationships

changes

weight

performances.

Application of weaning

12 days in pig herds.

Comparative results of the productivity

of

period of three years

J.

l’Élevage

Jouy

.rosas

seventy

from 5 herds

part

January

Duration of weaning-oestrus interval and prolificacy ^of

statistical study ^{of the} ^influence

(weaning- conception ^interval, prolificacy)

weaning (— 0 . 17 8

Application ^of weaning

¹² days ⁱⁿ pig ^herds.

period ^{of three} years