Table II: 1965 fresh semen 1967 pellet-semen

No. of | No. of | % 60 D. No. of
1st
Ins.
Loun.
Uu-Ky
Salp.
Osterb.

   

295449 | 209772 71.0 277507 | 199137
t0.0B

The smaller number of cows for the year 1967 is due to the
fact that cattle breeding is decreasing in the district
concerned.

STORAGE. Before the pellets are transferred to the tubes tkhey
are rinsed in pure liquid nitrogen in order to remove possible
loose particles.

Pellets to be distributed to the technicians are put in metal
tubes made according to Prof.GRAHAM,that is with an open slit
along the full lenght of the tube. Pellets for long-time
storing are put into aluminium tubes and are sealed. Every
tube contains separate freezings.The storage tubes as well as
the tubes used for insemination are marked with an electric
pencil, thus identification is safe.

Every third month the storage containers are cleaned and
disinfected with alcohol in the laboratory.

THAWING. The thawing solution consists of a sodiumcitrate
solution with the addition of 1 gr. of streptomycinesulphate
per every litre of liquid. 1 ml. of the extender is put into
sterile amgoules of 1.5 ml. The temperature of the ampoules
is 35 - 40 C when the pellet is added.

DISCUSSION. Every technician keeps in his nitrogen container
a supply of semen from Ayrshire bulls as well as semen from
the polled cattle of Finnish-breed. A crossing of the breeds
is immediately apparent in the offspring. Since no crossings
have been reported one must assume that no passing of sperm
from one pellet to another has taken place. The technicians
and the veterinarians report that the number of endometritis
cases have gone down since the use of frozen semen.

1066