Rit Landbúnaðardeildar : A-flokkur - 01.05.1955, Blaðsíða 31

Summary,
Some 30 years ago it became known tlirough feeding experiments in Iceland that
by using a small supplementary ration of herring meal to grazing sheep in winter
receiving a limited ration of hay, ewes could be more economically maintained during
winter tban by feeding hay alone. A daily ration of some 30 to 50 grams of herring
meal was recommended to ensure sufficient protein for maintenance of ewes in addition
to the proteins they obtained from the pasture and a limited quantity of hay. Most
Icelandic sheep fariners soon adopted the policy of feeding some herring meal to
sheep in winter and in years when herring meal was cheap they were inclined to feed it in
rather large quantities, even up to 150 g or more per sheep per day. As this method was
likely to be wasteful in valuable proteins, it was decided to find out by feeding trials
in successive years under varying grazing conditions what would be the most economical
daily ration of herring meal for ewes in winter.
In five feeding trials in North-East Iceland a comparison lias been made between
a daily ration of 50 g and of 100 g of herring meal per ewe as a supplementary feeding'
to grazing ewes receiving a limited, but varying' ration of hay according to the grazing
conditions during pregnancy. Three of these trials were carried out in successive years
on a farm where tlie sheep are partly grazed on seaweed while a farm with no access to
the seashore was chozen for the other two trials.
All the trials were planned in the same way. A number of mature ewes (84 to 136)
were divided into two even groups at the commencement of the trial according to live-
weight, age and fertility in previous years. In ecah trial ewes in both groups were fed,
grazed and managed in the same way, except that the ewes in one group received 100 g
of herring meal per ewe per day, while those in the other group received only 50 g
of herring meal per ewe per day throughout the trial.
One of the trials started a fortnight before the beginning of the mating season,
two at the beginning of it and two some 4 to 5 weeks later. All the trials continued
until the beginning' of lambing in the spring. The ewes were weighed at regular
intervals throughout the trials and their lambs were weighed dead and alive 4 months
old. The ewes were g'razed whenever weather conditions permitted and the quantity
of hay fed varied greatiy according to the fill the ewes got on the pasture during the
daytime.
Results.
1. During the first 3 montlis of pregnancy the ewes receiving 100 g herring meal
did not thrive any better than those receiving 50 g of herring meal per day during
periods when the quantity of hay (good cultivated meadow hay) exceeded 25 to 30 per cent
of the total requirements for maintenance. During the last two months of pregnancy the
same applied, provided the hay ration amounted to some 50 to 60 per cent of the total
requirements for the maintenance of the ewes and the growth of the foetus. In some of
the trials during periods of good grazing conditions when the quantity of hay fed
during early pregnancy was below 30 per cent and during late pregnancy below 60 per
cent of the total requirements for the maintenance of the ewe and the foetus, the
ewes receiving 100 g of herring meal per day remained in better condition than those
receiving 50 g per day, indicating great deficiency in protein and/or minerals in the
pasture.