a comparison of perocent unstained spermatozoa in
stgaws thawed at 35 C in 30 sec. and straws thawed at
75°C in 12 sec. The two different diluters lactose-di-
luter and milk-diluter are used. In both groups a con-
siderable difference respectively is found.

» comparison of thawing at 350C in 30 and 15 sec. gave
no difference.

Table 1. Comparison of percentage ugstained gpermatozoa
in straws thawed at 35 C and WS- Cre

Diluent for group I : 11% lactose - L4,7% glyce-
rol - 20% eggyolk.

Dildent for group II: 11% skimmed milkpowder -
2¢ fructose - 7% glycerol - 5% eggyolk.

Strgws thawed at Strgws thawed at

35-C in 30 sec. ZSsCainy Lesisecte Differen-
No.of No.of % un- No.of % un- ggogezzé
bulls sperm stained sperm stained 35oC
count. sperm count. sperm 7
Group I 20 20270 46,8 23580 60,8 11,0
Gronpr Tl 119 10590 46,0 12880 67,9 21,9

I A, D T et e

In addition to these experiments a field trial was carried
out, comparing per cent N.R. after insemination with semen
frozen in ampulles %nd semen frozen in straws, thawed in
jce-water and at 75 C in 12 sec. - respectively. Plastic
tubes adapted to straws have been used for insemination
(8). The comparison involved semen of seven different
bulls of Norwegian breed and was based upon split samp-
les. The diluent used for ampulles was skimmed milkpow-
der - fructose - eggyolk - glycerol (6), and for straws
lactose - eggyolk - glycerol (5). The results of the

first part of this trial have been reported earlier

this year (9) and the final results are given in table 2.