Vie CONG. INTERN. REPROD. ANIM. INSEM. ARTIF., PARIS, 1968, VOL. lI

A nalysis of the copulatory pattern in the boar.

S. WIERZBOWSKI and E. WIERZCHOS
Institute of Zootechnics, Department of Animal Reproduction and A.l.,
Balice/Krakow, Poland.

The copulatory pattern of the boar differs very much from sexual
behaviour in other farm animals, a long copulation being the most
striking difference. The purpose of our experiment was to analyze the
course of copulation in the boar by dividing it into several successive
phases.

M ATERIAL AND METHODS.

5 Landrace boars, aged 9 - 13 months and weighing 140 - 200 kg
w ere used as subjects. None of the boars had had previous mating ex-
perience. The boars copulated daily at 1,2,5,8,11,14,17, and 20-
day intervals for a period of 20 days, and also at 1 hour-intervals during
a 12-hour period. Semen was collected by means of the "gloved-hand"
technique using a dummy. The duration of copulatory reflexes was
m easured by stop-watch (accuracy 1/10 sec.) according to the scheme
shown in the table. Comparison was made by studying the course of
219 copulations in 5 boars.

RESULTS.

The interrelation of the sexual reflexes in boar copulation has been
presented in Figure 1. The analysis of variance proved that the interval
between collections did not affect the time of any of the reflexes ex-
amined. However, there was a highly significant correlation between
the duration of erection and seeking movements, and that of the total
copulation time. The duration of the first phase of copulation com-
prising mounting, erection and seeking movements, was of labile type.
Both the individual characteristics of the animals, and the effect of ex-

ogenic and endogenic factors were manifested, thus causing a consid-
erable variability in the time of these reflexes which ranged from 52 -
143%. The ejaculation time was similar for all boars. The stability of
this reflex was proved by a comparatively low variability ranging from
16 - 30%.
D ISCUSSION.

Analysis of the course of copulation was facilitated by dividing
sexual reflexes into those provoked by stimuli acting from a distance
(mounting, erection), and those caused by stimuli affecting receptors
on the penis (copulatory movements and ejaculation) (1).

This division also helped to define individual activities, and to
determine their duration. The course of ejaculation was found to be
most regular and independent. The duration of semen output was com-
paratively constant, |t seems that findings on ejaculation in boars
lasting up to some scores of minutes may be just a misinterpretation of the
boar's ability to repeat copulation and ejaculation almost immediately
(2).

1681