Factors affecting the reproductive performance of sows Varley M.A. in

Varley M.A.

in

Aumaître A. (ed.).

The production of pig meat in Mediterranean Countries Paris : CIHEAM

Options Méditerranéennes : Série Etudes; n. 1989-I 1989

pages 101-106

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101

Factors affecting the

reproductive performance of sows

A.

University of Leeds - United Kingdom

There are many diverse factors which can have a profound effect on the reproductive performance of are:

the genotype of the sow and boar, the health status of the herd and the general environment provided for the

paper to concentrate on those factors which are under direct management control and which are e c o n o m i c a l l y s i g n i f i c a n t . C o m p o n e n t s o f reproductive performance to be considered are:

lactation length, climatic and social environment and prolificacy.

There has been progressive improvement i n recent years in sow productivity and this trend seems

likely to

Livestock Commission show that over the years 1 9 7 0 - 1 9 8 4 , s o w p r o d u c t i v i t y in t h e U n i t e d piglets reared per sow per year to 20.0 reared per sow per year. There is great variation between

herds in this respect and in 1984 the top 10% of herds weaning piglets between 14 and 18 days of age were recorded as rearing 26.8 piglets per sow per year (2.6 litters per sow per year; 11.1 piglets achieve performances at this level but there may be lessons to learn from these top herds which could help the average farmer.

- Environmental effects

is of the

on of t h e

sow. and

is

conditions in addition to the imposition of good to the animal, can also be associated

of efficiency.

components which may play a

of is

needed. (1971) has suggested that high is associated with

size a t Tomes and

Neilson (1979) is

not always so. Obviously the effects of h i g h on size in the female pig confounded by

(1975)

two weeks

mating

Table 1 a by

(1985) showing that heat effects on

development of Table

&, (1985)

I

I

1

Leucine in

times when deficiency of piglets is most likely to be seen.

of

is likely to be involved in seasonal which

1982;

1981; et al., 1982) no study to date has a significant effect of

to l

The social of

of the most significant of

is much of

pig is an excellent model this.

of

of is a

involved in we may develop systems of

building designs which fulfil1 the of

is evidence social

of sows and gilts can be

a t been

(1978),

at sows housed individually.

(1981)

size. These sows

12 to

which sows

Table 2 gives the

by et

(1981) between the each

of

sows which showed

Table 2: Correlation coefficients between reproductive performance

and the quality of stockmanship (1981)

I i

%

No. of piglets

I I

of sows with humans

-

-

but it does

in the sow affected by good and bad stockmanship in the same way that milk yield in

be influenced by of

the 1972).

has on

sows some may be

of manifests itself as complete

much of sow

- ^Sow nutrition, body condition and prolificacy

a n abundance of

the last 20 of

sow body composition

This has a

sound of

is established sows

intake only a above maintenance.

is a cost effective means of

now become

levels of sow,

too many animals without the middle band of

body condition. be at low

to

individual sow body condition and adjust feed the ideal body condition and body weight change

phases of a sow's life. As as

is little doubt that the sow can without loss of

Cole, 1978b; and

of body condition, the incidence of

dysfunction likely

been a n last

few to

sows and gilts in (i.e. up to

of post coitum been open to much discussion. The evidence indicates that at least in gilts, it is advisable to

feed intake in the weeks 1968).

well defined but a by Toplis, Ginesi showed

2 4 of a diet containing

13 of 3 a n d 30 days post

no

of a t day 30

sows is often a to

body condition losses

possible to apply

of following

of

- Early weaning

The application of 20

played a i n sow

biological effects of now well

a s lactation length is weaning to conception, conception

Cole, 1978b).

is

is given by the equation:

Y = 6.8

+

Y = X =

the conclusion is (7-20 days)

no of annual sow

it is 2.8

has been made that the optimisation of weaning

age is weeks.

The question of when to wean is not so simple and be

of the

available management skills. would that if sow is the main goal then weaning at 21 days is

of time. What does is

model of the sow

all of the known biological facts and the economic The data depicted in Figure 1 a new with an intensive building system

good be seen

that at slightly less

t h a n a 2 0 d a y l a c t a t i o n l e n g t h . F i n a n c i a l a weaning age of about 35 days. is

on capital at shows a positive value.

Figure 2

at the same point as the

a t

much 1970s. The optimum age

to wean to

and although it to be

weeks of age, it if the economic situation changes. What is needed inexpensive

on soya

low cost will

knowledge of of

the young pig is much advanced.

Although most 25 sow

a week weaning system, they by accepting 22 piglets a five week weaning system at today's

knowledge.

options

- Endocrine status of early-weaned sows

of

Atkinson and 1981;

Atkinson, 1984; 1983).

of do

and conventionally

teated sows (weaned a t is

and 1983;

et al., 1984)

is timing of ovulation

peak does not

by et al., 1984.

blood levels of

implantation of blastocysts.

of this is open at the moment sows show

A of conventionally weaned sows show

the same is

than One possibility

is known to a s

a may be that some animals

.

as a compound

the of a

is

to be done in this field conclusions it does

may

V - Prolificacy and neonata1 management

of

is usually by to

of

a of it

is i m p o s s i b l e to m a x i m i s e a n n u a l s o w on

a t

7.8 1984,

data).

is a l s o of

of little consequence 12 alive if 15% of these die within 48 of often is the case.

incidence of neonata1 deaths and these include c o l i

of now being used

widely

technical options open to

- Conclusions

a is a of

hope t h a t it may be

is a made by

of

animals size. now have the

option to select a company’s gilts on the basis of of a good genotype, it is t h e n

of good

of some of the points listed below.

Use of a n good

hygiene;

Stocking density sows not too high;

Feed sows and gilts as body condition;

sows.

options

of a sow accommodation;

Avoid

of Avoid the imposition of on the animal,

at

of s t o c k m a n s h i p a s w e l l as t o m a n a g e m e n t

of pigs to size. is of

of the highest good the genotype, the housing, the feeding and the style of management, the actually tending to the animal's needs.

of

of 16 to 20

of t h e , b a s i c m e c h a n i s m s i t might yet be possible to sell bacon pigs a 100 sows.

and Chaney, 1968. Feed intake and Exp. Stu. No. 176:33-35.

S. and 1983. changes in

sows weaned a t two stages of lactation. J. 67:161- 172.

L.G. and 1982. of a 16 h =

or a 8hL = to influence

efficiency in sows. Can. J. Anim. Sci. 62:141-145.

and 1981. Effect of light changes on

swine of

1981. pp. 21-23.

and W.J. 1978. The of on the success of matings. Appl. Anim. Ethol. 4:341-347.

A. P. Willems, 1981. The sows to the human beings

to Sci. 8,67-74.

and 1977. Thin sows. 1.

on the fecundity of

J. Sci.,Camb. 89:513-622.

Lapwood, W.C. Smith, and

1944. of

lactation 10 or 35 days. J.

Fert.70:95-102.

J.W., F.L. Cunningham,

1982. The effect of extended

on of the sow, J.Anim.

Sci. 54918-921.

1971.

ed. Cole, pp. 91-106.

London.

1972. A study to influence of the on milk yield. J. Sci. 1:l- 45.

A.G., 1975.

17, p.14.

Tomes, G.J. and Nielsen, 1979.

of

conditions. Wld. Anim. 15:(1) 9-19.

Ginesi, and A.E. 1983. The influence of high food

Anim. 37:45-48.

and Cole, 1978a. between

the weight change of the sow Soc. Anim. 1978. 368

a n d Cole, 1978b. S t u d i e s . i n s o w 6 . The effect of lactation length on implantation losses. Anim. 27:209-214.

Atkinson, 1984. Effect of lactation length of the sow on plasma

17 Anim. 38:113-119.

T. Atkinson, and L.N. 1981. The effect of of

1 9 8 5 . of of

of Ed. Cole, and

J. 33.

25 GMISOW

f

za

4 0

16 20

10

500

3

3

3

3'

Figure 1 : Effect of weaning age on economic aspects of pig production

S S MARQIH 8 0 W --i

W +l O +S

O

ON CACltAL

-10 -16

10 20 30 40

WEANINQ AGE (days)

Figure 2 : The effect of weaning age on profitability Great Britain

I

1975

.costs

\ \

\

\

\

\ \

Current Feed C o s t s T9

5

I l * ^{I I 1}

14

28 42 49

Weaning Age (days)

options