Íslenskar landbúnaðarrannsóknir - 01.09.1969, Page 39

ELDI KÁLFA Á UNDANRENNU OG TÓLG 37
S UMMARY
CALF-REARING TRIAL ON MILK SUBSTITUTE
Ólajnr Jónsson and Reynir Bjarnason
Following up prior research on how £ar it is possible to go in the field ol'
saving butterfat in veal production, it was decided to examine whether butterfat
could not be substituted by a fat of foreign origin.
A calf-rearing experiment with twelve bull calves was undertaken at the re-
search station in Laugardælir. Ten calves were fed with a milk substitute, but
two acted as control calves and were fed with whole milk, skimmed milk, hay
and concentrates.
The purpose of the experiment was to examine what influence the milk sub-
stitute had on growth, health and carcass of calves, which were fed with the
substitute up to 100 days of age.
The milk substitute used in this experiment was made up of a spray-dried
mixture of partly vacuum-dried skimmed milk plus melted emulsified lard,
and to this was added a premix containing minerals, micronutrient and anti-
biotics.
The milk substitute’s constituents being 78% skimmed milk, 20% lard and
2% premix (all figures on a dry matter basis) and its moisture content being
2%, the nutritive value of the milk substitute was 1.65 Scandinavian Feed Units
and 255 g crude protein jter kg.
The experiment showed that the milk substitute in question is a satisfactory
feed for veal production, at least when fed to calves to 100 days of age.
The growth rate of the calves on the milk substitute was 750 g live-weight
gain per day, while that of the control calf was only 430 g per day. The average
carcass weight of the former was 56.4 kg and their carcass percentage was also
decisively higher than tliat of the latter, which only had an average carcass
weight of 31.3 kg.
The test calves had quite a satisfactory conversion ratio, but for each kg
live-weight gain they consumed 1.70 kg of the milk substitute and 2.12 kg for
each carcass weight. The appearance of the test calves’ carcass was also better
than that of the control calves.
HEIMILDARRIT:
JÓNSSON, Aðalsteinn & VlLHJÁLMSSON, Sverrir,
1968: Athugun á framleiðslu kálfafóðurs úr
innlendum hráefnum. Rannsóknastofnun
iðnaðarins. Fjölrit. Nr. 1, 71.
JÓNSSON, Ólafur, 1969: Eldi sláturkálfa á
blöndu af undanrennu og nýmjólkurmjöli.
ísl. landbún. 1, 3—27.