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Transactions of RHASS Volume 1940 - Page 017

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Year 1940
Transcription
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22 STOCK-FEEDING UNDER WAR CONDITIONS.
As regards the gain in food value, allowance must first
be made for a loss of dry matter—some of the substance of
the straw dissolves in the soda and is run to waste. This
amounts to nearly 20 per cent. In other words, a ton of
straw containing fully 17 cwt. of dry matter will yield about
3% tons of wet straw-pulp, containing about 14 cwt. of dry
matter. On the other hand there is a very marked gain
in digestibility, and hence in food value. Dr S. J. Watson
finds that average wheat straw, which has a starch equivalent
of about 13 lb. per 100 lb. dry matter, yields a pulp with a
starch equivalent of fully 40 lb. per 100 lb. dry matter. The
corresponding figures for good oat straw, on a dry matter
basis, are about 22 and fully 55. The total starch equivalent
is thus increased, in the case of wheat straw, to fully two
and a half times the original figure and, in that of good oat
straw, is fully doubled. There is, of course, the further
practical point that a very bulky food, with very limited
uses on the farm, is converted into a fairly concentrated one
which can be put to a variety of uses. The product from
wheat straw is of about the same concentration (starch
equivalent in relation to dry matter) as really good hay.
The product from good oat straw is little inferior to beet pulp.
The economics of the process will, of course, depend upon
the value assumed for straw, on the market prices of feeding-
stuffs and on the profits to be expected by keeping stock
which otherwise, owing to shortage of feeding-stuffs, might
have to be sold. If, however, we assume a flat-rate value of
2s. 6d. per unit of starch equivalent (implying that eats
are worth about £8, 10s. per ton, beet pulp about £8, and
good hay about £5), the calculations would be as follows :—
AVERAGE WHEAT STRAW—
Costs——
One ton straw . . . . . . . £1 8 0
Treatment (materials and labour) . . . . l 17 0
Total . . . . £3 5 0
Value—
14 cwt. dry matter as pulp at £5 per ton . . . 3 10 0
Balance profit . . . £0 5 0
GOOD OAT STRAW—
Costs——
One ton straw . . . . . . . £2 10 0
Treatment (materials and labour) . . . . l 17 0
Total . . . . £4 7 0
Value——
14 cwt. dry matter as pulp at £6, 17s. 6d. per ton . 4 l6 3
Balance profit . . . £0 9 3
STOCK-FEEDING UNDER WAR CONDITIONS. 23
It thus cannot be claimed that, at the prices assumed,
the process would be highly profitable. But it does seem
to offer a very valuable means of utilising a by-product, of
reducing the farmer’s dependence upon his feeding-stuffs
merchant, and of increasing production from our own soil.
It may be noted that the processed straw contains a negligible
amount of protein. Straw contains but little protein originally,
and most of this is dissolved by the soda solution and is lost.
The material, fed in reasonable amounts, is quite palatable to
both cattle and sheep. Feeding cattle of ordinary size will
readily clear up about 50 lb. of wet pulp (containing about
10 lb. of dry matter) per day. Some experience will be required
in compounding rations with the new material, but as a
general guide it may be suggested that a 10-cwt. feeding
bullock might have 50 1b. swedes, 50 lb. wet straw pulp,
5 or 6 1b. hay, and 2&3 1b. of a high-protein cake such as
decorticated earth-nut. This is calculated to produce a daily
live-weight gain of 2 lb.
Finally, it should be noted that trials with straw pulp
in pig-feeding have so far, as might indeed have been expected,
given unpromising results. At the Rowett Institute trials
with wheat straw have shown that, whereas the untreated
straw has a minus food value (the pig spending more energy
in trying to digest the straw than it gets back from the small
amount actually digested), the treated material does, so to
speak, yield a small balance of profit to the animal. But
the material would, it seems, do little except to satisfy the
animal’s hunger.
PROTEIN SUBSTITUTES.
It is well known that one of the main difficulties encountered
by Germany in her efiorts to achieve self-sufficiency has been
in the matter of oils and fats. This is because the main
oil-seeds of commerce—palm-kernel, coconut, cotton, earth-
nut, &c.——are produced by tropical plants. Some progress
has been made with the production of soya beans in South
Germany, but, in the main, the solution has been to resort
to the strictest rationing of soap, margarine, and other pro-
ducts of vegetable oils. As a secondary result of the reduced
supplies of oil-seeds there has been a great scarcity of oil-
cakes, upon which the German farmers, like ourselves, used
to rely for balancing their rations—tie, for getting the required
proportion of protein or albuminoid.
In Germany the scarcity of oil—cakes has been met in part,
but only in part, by changes in cropping—by growing larger
acreages of beans, lupins, and other pulse crops, and by
ensiljng protein-rich herbage such as young grass or clovery
Title Transactions of RHASS Volume 1940 - Page 017