Great Lakes Dairy Sheep Symposium - the Department of Animal ...

a) concentrates supplied during milking should have low CP concentration, not more than 12%
to 13% of DM, and the protein should have low rumen degradability. Negative effects of
soluble N supplements on the milk yield of ewes grazing young pastures have been reported
(Malik et al., 1999). In addition, simulations done with the CNCPS Sheep (Cannas et al.,
2004) have shown that with immature and CP rich pastures, even when there is a high excess
of rumen N, the MP requirements of the ewes might not be satisfied (Cannas, unpublished);
b) concentrates supplied during milking should have a fairly high fibre concentration (from
17% to 20% of crude fibre; from 25% to 35 % of NDF), so that they stimulate rumination
and compensate for the low fibre content of the pastures, and high starch concentration, to
supply energy to the bacteria. The fairly high fibre concentration should be achieved by
adding to concentrates mixtures feeds with highly digestible fibre, such as soybean hulls or
beet pulps, to the concentrate. These fiber sources stimulate rumination in sheep (but not in
cows) and also provide energy to bacteria. A mixture of slow fermenting (maize or sorghum)
and fast fermenting (barley, oats or wheat) starch sources should be used, so that a sufficient
release of energy can occur even after many hours from the last supply of concentrates. The
overall goal is to improve the synchronisation of the fermentation of the proteins of the sward
with that of the energy sources given at milking;
c) nitrogen fertilisation should be carefully managed and sheep should not graze pastures for
several days after fertilisation, especially when low temperatures or drought reduce the
conversion of N fertilisers into plant proteins;
d) when the sward is wetted by dew, grazing time should be reduced and the flock should be
brought on pasture in the late morning. If the ewes go on pasture several hours after the
morning milking, during which they received the first supply of concentrates, it is advisable
to supply some feedstuffs shortly before grazing time. This practice avoids that they eat the
pasture too fast, thus reducing the risk of ammonia overload. The supplements should be rich
in energy and digestible fibre, and low in protein. For this third meal (assuming that the other
two supplies of concentrate occur at the morning and evening milkings) the best supplements
are, in order of preference, beet pulp, maize silage and silages made from wheat, barley or
oat grains at milk-dough stage mixed with some grains. Pelleted feeds may also be used, as
long as they have the characteristics described above. Besides limiting the rate of intake in
the first hours of grazing, the third meal guarantees a supply of energy for rumen bacteria
during the first hours of grazing, so that they can be more efficient in using rumen ammonia.
In addition, it helps in splitting the daily allowance of supplements in several meals;
e) good quality hay and silages should be added at night when the ewes are indoors, especially
when grazing time is restricted to avoid excessive CP intake; and
f) grazing time, amount and type of concentrates and of stored forages, and number of meals
should be based not only on the quality and availability of the pasture but also on the
indications derived from an integrated analysis of all nutritional indicators. In the short term,
special emphasis should be given to milk urea concentration and to the characteristics of the
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