Vle CONG. INTERN. REPROD. ANIM. INSEM. ARTIF., PARIS, 1968, VCL. I

THE EFFECT OF BOARS ON THE FERTILITY OF THEIR DAUGHTERS

B.SIMOVIC - M.MILOJIC
Faculty of Agriculture, University of Belgrade

Fertility of pigs is very significant for the success in

production and its economy. The profitableness of the pro-
duction depends on the nunber of piglets bred,or the fat-

tened animals per sow in the course of the year. In bre-

eding practice it 1s usual to evaluate the mother only,

while the boar is primarily evaluated accordting to the

feeding efficiency and production quality.It was on this

principle that the Danish Station for the Control of Fat-

tening Capacity of Pigs in most countries in the world,has
been founded.

However, it has been observed that there are definite dif-
ferences in the fertility of the offspring due to the ef-
fect of boar, which may be considerable sometimes. Thus
for instance, if sows are mated by a given boar, they show
o definite fertility, while if the same are mated with a-
nother boar the fertility will be different(3,4,2,1,5)

The question of the boar fertility is becoming more ur-—
gent in breeding practice of many countries including Yu-
goslavia, which is due to the rapid spread of artificial
insemination on big pig farms, having a large number of
sows. Under such conditions the fertility of boars may ha-
ve a great influence.

MATERIAL AND METHOD.— The investigation on the fertility
of boars was performed on breeds of Dutch Landrace at a
big farm which breeds about 1500 sows.

The animals used for these investigations originated from
uniformly selected parents (according to age, fertility
etc.) while the tests were implemented by the progeny test.
The investigations covered 17 boars which were of the sa-—-
me age at first serving (about 9 months 0ld) and they ma-—
ted at short intervals with a suitable number of sows. Of
all the sows which mated, their daughters were 1left for
further reproduction, so that there were at least 5 da -
ughters from every boar respectively.The daughters were
mated with boars of the same breed and corresponding age
which were not related, and their fertility was recorded
during the first four farrowings in succession.

RESULTS OF INVESTIGATION.— Fertility of daughters of the
investigated boars varied considerably in absolute values,
from first to fourth farrowing.

In the first farrowing,on average for all daughters the

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