Vle CONG. INTERN. REPROD. ANIM. INSEM. ARTIF.,, PARIS, 1968, VOL. i

MOTION PICTURES OF EJACULATION IN THE BULL

G.E. SEIDEL, JR. and R.H. FOOTE
Department of Animal Science, Cornell University
Ithaca, New York, U.S.A.

The mechanics and pattern of ejaculation in the bull has not
been thoroughly studied. Bonadonna (2) used a glass extension on an
artificial vagina (A.V.) and observed that semen emission normally
occurred at the time of maximum penis extension. Considerable "loss
of sperm may result in routine semen collection due to improper size
of A.V. and variability in site of semen deposition (G55) 5= High
speed motion pictures of ejaculation were taken to examine the
following:

1. Length of penis extension.

o, Stimulus time, which is defined as the time from first con-
tact of the penis with the A.V. until semen emission takes
place.

3, Actual semen emission time.

4, Overall pattern of ejaculation.

5. Effects of improper tactile stimulation on ejaculation.

MATERIALS AND METHODS. Color motion pictures were taken, generally

at 64 frames per second, through a transparent lucite tube 45 cm

long which was connected to an A.V. Eight bulls were collected twice
weekly at 50-minute intervals for six weeks using either a mechanical
dummy or another bull as a teaser. The lucite extension tube was
connected to an A.V. 30 cm in length at 55°C as well as an A.V. 15 cm
long warmed to 40°C in order to photograph the effects of different
stimuli on ejaculation patterns. Sexual preparation was held constant.

RESULTS AND DISCUSSION. Several of the mean responses which could be
determined from the film are shown in Table 1. Differences among

TABLE 1. CHARACTERIZATION OF BOVINE EJACULATIONE/
e
Criteria
Length of
penis ex- Stimulus Emission
Number of tension time time

Components ejaculates Cl. secC. seC.
Grand Mean 48 53l 1.0 «29
Highest bull 6 59.5% 1.3%% 39
Lowest bull 6 50.0 0.8 ]
First ejaculates 24 54.8 0.9 «29
Second ejaculates 24 52.0 131 29

al Based on 48 ejaculates with a mean volume of 6.4 ml and a
mean sperm concentration of 1575 x 10 sperm/ml.
g = R B 0 {0 T

153