138
ABSTRACTS
[Vol. XXIII, Part II,
Long term storage of bull semen frozen at very low temperatures (-79 C.) POLGE,
C. AND ROWSON, L.E.A. (1952). Proc. II Int. Congr. Physiol. Path. Anim.
Reprod. A.I. 90-98
D ATA are presented from recent experiments conducted by the authors in Eng-
land on the preservation of bull semen in solid carbon dioxide at 79°C. Survi-
val of bull spermatozoa at low temperatures depended on the addition of glycerol
to the diluent so as to get a 10 per cent concentration in the diluted semen. It was
observed that dilution is best carried out at 5°C. Before freezing, the semen samples
are allowed to remain for 12 to. 20 hours at 5°C and subsequent cooling is done upto
a temperature of -15°C at a rate not exceeding 20 per minute and thereafter at a
quicker rate. Eighty per cent of spermatozoa thus frozen resumed motility when
thawed at 40°C. Thirty-eight cows inseminated with frozen semen gave a concep-
tion rate of 79 per cent as against 76 per cent obtained from unfrozen samples.
Pregnancies have been obtained with frozen semen 'banked' for 20 weeks. The
possible use of the new method of semen preservation in artificial insemination work
has been discussed. [S.S.P.]
A simplified method of culturing ascarid eggs. RIEDEL BERNARD B. (1951). Trans.
Amer. micro. Soc. 70, 57-58
R IEDEL described a simple method of culturing ascarid eggs. The mature females
of Ascaridia galli were transferred to large, glass vessels containing water, to
a depth of at least one inch, and 3-5 c.c. of a two per cent solution of formalin. All
cultures were incubated at room temperature, 20°C or higher. Whenever ova were
required for infections, some of the ascarids were ground in a mortar and the eggs
filtered through several thickness of cheese cloth and concentrated with a centrifuge.
When cultures became contaminated with fungi, either the latter were floated
off the surface with a rapid stream of tap water or the ascarids were transferred
to clear, moist chambers. Some of the embryonated ova prepared by this method
had been kept for one year, and the degree of infectivity was found to be satis-
factory for experimental purposes. [K.N.M.]
The significance of fæcal egg counts in the diagnosis of parasitic gastro-enterites of
cattle. ROBERTS, F. H. S., O' SULLIVAN, P.J. AND RIEK, R.F. (1951). Aust.,
Vet. J. 27, 16-18
T HE authors have discussed the value and significance of fæcal egg counts.
The egg counts may be influenced by a number of factors, e.g. the regularity or
otherwise of oviposition, the regularity the fæcal material enters and is discharged
from the rectum, etc. which cause variation in egg counts. Despite such variations,
however, the authors had found that fæcal egg counts, provided their limitations
were realised, might give a very valuable assistance in studies concerned with the
helminth population in the host. They had given the counts considered indicative
of pathogenic infestation for a few common nematodes as follows.
Hæmonchus contortus. In calves 6 to 12 months old in which H. contortus
was the dominant species, a count of 1,000 e.p.g.* or more was frequently accom-
panied by serious symptoms of hæmonchosis.
*Eggs per gram of fæces