The tubes were stoppered with rubber and placed
in a refrigerator at 2-5°C for 24, 48 and 72 hr.

The same tubes and dilution conditions were u-
sed for experiment 2, but before pipetting the
semen into the diluent, oxygen (99.5 % purity) was
bubbled through the latter for 30 seconds. The re-
sulting fluid to gas ratio after the tubes has
been stoppered with rubber was 1:4.

In experiment 3, smaller tubes of 5 ml capaci-
ty (internal diameter: 13 mm) were filled with
0.5 ml of the diluent which was treated as in ex-
periment 2. The semen (0.5 ml) was then added and
the tubes were stoppered, in such a way, that also
a fluid to gas ratio of 1l:4 was obtained. In both
experiment 2 and 3, semen was stored for 24, 48
and 72 hr.

In each experiment 4 groups of 12 hens each we-
re inseminated for each storage time, at least at
two different intervals. Inseminations were perfor-
med intra-vaginally, close to the utero-vaginal
junction, with 0.1-0.12 ml of stored semen. Eggs
from hens in which the utero-vaginal junction was
penetrated by accident were discarded.

Fertility results were based on the number of
fertile eggs laid from the 2nd to the 8th day in-
clusive after insemination. The eggs were broken
out after 3 to 5 days incubation and observed for
embryonic development. A hen was classified as fer-
tile when she had laid at least one fertile egg du-

ring the 7-day period.

Percentages of fertility were transformed to
angles and analysed according to Snedecor (1950)
and Duncan (1955).

RESULTS. The results, summarized in the following
Table show a beneficial effect of oxygen on ferti-
1ity, but only under the storage conditions in the
small vials. Although the ratio of fluid to gas was
the same in both storage tubes, the supply of oxy-
gen from the gas phase might be more efficient in
the smaller vial, since, proportionally, a greater
number of spermatozoa were in contact with the gas
phase. This is, to some extend, in agreement with
the findings of Proudfoot and Stewart (1967).