(1) The pH of the vaginal secretion of mature merino ewes, measured during
oestrus, gave a mean value of 6·648, with a range of 5·85 to 7·40. During
mid-dioestrus the mean value was 6·694, with a range of 6·00 to 7·60. During
pregnancy the mean value was 6·272, with a range of 6·00 to 7·00. There are
indications that there is a tendency to slightly increased acidity during oestrus
(2) There are indications that there is a slight tendency for male offspring to
be associated with a pH approaching neutral or alkaline measurements.
(3) The percentage fertility was higher with pH measurements below 7
(82·51 per cent.) than with those above 7 (73·18 per cent.). There are indications
that an alkaline medium may be detrimental to the vitality of the spermatozoa
in the vagina when pregnancy is used as an indicator.
(4) Forced exercise increased the vaginal temperature of ewes when they
are compared with ewes, kept under similar environmental conditions, which were
allowed voluntary exercise.
(5) The temperature of the vagina (within a range of 100·2°F. to 106·2°F.),
at the time of mating or artificial insemination did not influence the sex of the
(6) The temperature of the vagina, within a range of 100·2°F. to 106·2°F.,
did not make a significant difference in the resulting pregnancies in three groups
of sheep with mean temperatures, at 1st and 2nd matings or artificial inseminations,
of: (1) 103·286, 103·264, (2) 103 ·244, 103·096, and (3) 104·017,
104·108 (temperatures are recorded in °F.).
(7) The gestation period, for 79 normal pregnancies in merino sheep, showed
a range of 146 to 156 days, with an average of 151·4 days.