Fjölrit RALA - 15.08.1980, Blaðsíða 36

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during the summer did not add anything to their carcass during the experi-
mental period, whereas the lambs grazing the aftermath that had not been
grazed before during the summer gained 3.2 kg carcass weight éind the léunbs
grazing the kale gained 2.0 kg. It has to be stated that the kale did
not last all the grazing period. The weight of the peth, abdominal fat
and livers increased most in the léunbs that grazed the ungrazed aftermath
and least in the lambs grazing the bog. The same was true for the carcatfs
and meat measurements, but the weight and length of the céunnon bone was
higher in the bog grazing lambs than the lambs grazing the previously grazed
aftermath. As expected the riamen NH^-N was lowest in the bog grazing léunbs,
but it is interesting that it was highest in the léunbs grazing the previously
grazed aftermath. The ratio between the acetic acid and propionic acid was
lowest in rumen of the lambs that gained the most i.e. the lambs grazing the-
aftermath that had not been grazed before during the summer, but highest in
the lambs grazing the uncultivated bog. The study indicates that the
breakdown in the rumen was greatest in the lambs grazing the previously
grazed aftermath and this could be due to decreased flow of digesta thioug the
rumen that could be caiBed by lack of fcod intake. Similarly the breakdown in
the rumen was also high in the lambs grazing the unimproved bog. These
lambs were also most probably not receiving enough protein.
The horses (ponies) in Kalfholt did extremely well. Similarly the ewes
gained considerable weight whereas the lambs were poor. The horses did
not benefit frora mixed grazing with sheep, whereas the lambs seem to have
beneffted from grazing with the horses. The increased performance of the
lambs, however, is not great enough to make them comparable to the lambs
grazing the mountain pastures in Iceland.
As indicated before half of the sheep had to be removed from the most
heavily grazed pastures at Kelduhverfi 19^ of July because of lack of
feed. The ewes that were left behind in the experiment kept on loosing
weight in spite of the decrease in grazing pressure. In the light unferti-
lized paddock the ewes gained some weight in August éind September. On the
fertilized paddocks, both the herbicide treated cind untreated, the ewes did
well, except in two heaviest grazed pastures on the herbicide treated land
where they did not start gaining weight until middle of August. The lambs
did well on the fertilized land and the carcass weight was better than the
year before. Both on the unfertilized and the herbicide treated fertilized
land the carcass weight was not as good as in previous years.