STOCK FOODS

Manawatu Standard, Volume LII, Issue 242, 12 September 1932, Page 10

STOCK FOODS

THEIR COMPARATIVE VALUE

Bulletin No. 37, issued by the Canterbury Chamber of Commerce, and prepared by Lincoln College, deals with the question of stock foods, as follow When stock feeds are abundant little consideration is given to their relative values. Year after year, however, there is a period cf scarcity, and during that time much thought is devoted to the problem of feed supply. The following information is supplied in the hope that it will provide the basis of a better understanding of the problem in the future. Stock feeds are composed of six main inerc-dients, water, protein, ash, fat, fibre, and carbohydrates, all of different digestibilities and of different values to the animal. Tables of chemical composition alone givo insufficient information to the stock feeder, but if it wore possible to express chemical composition, digestibility, and energy value in a single figure, comparison would bo much easier.

STARCH EQUIVALENTS.

These single-figure values, called starch equivalents, are given in a table below. All feeds are compared with starch, sinco that is the commonest food, making up ns it docs the bulk of wheat, oats, and other grains. “Starch equivalent” is defined as tho number of pounds of starch that have tho samo fat-producing capacity as 100 pounds of the particular feeding stuff, taking info account tho composition, digestibility, and availability of the ingredients. Tho calculated values agree closely with thoso obtained in feeding trials. For tho purposo of using foodstuffs a knowledge of starch equivalent, dry matter, digestible crude protein, and “V” numbers is required. “V” numbers are the percentages of total digested energy that the animal can uso for growth purposes. These percentages depend on the proportion of fibro present; when there is no fibre V equals 100 as in milk; when there is considerable fibre. V may bo as low as 40 as in straw. Tho remaining 60 per cent, of tho digested energy can be used only for tho production of body heat, and in winter such beat energy is a very desirable feature of the ration. This lieatproducing energy is not included in the starch equivalent value, so that .feeds with low V number's are more valuable for maintenance purposes than their starch equivalent indicates. Y numbers mark tho division bot.woen feeds that can bo used for growth purposes and those the cm be isod for maintenance. Where tho V number is greater than 50, tho feed is suitablo for growth, below 50 for maintenance only. The following table gives the standard value for dry matter and digestible protein contents, as well ns starch equivalents and V numbers of the commoner feeds: —

TABLE I.

c a S -I O •£ «—a . o ~ Feed Stuff. s f> >. -5P = = § = q o O cc o

LIMITATIONS OF STARCH EQUIVALENTS. It is well known that feeds aro not interchangeable pound for pound. It must also bo stated quite definitely that thoy aro not interchangeable on equal amounts of starch equivalent. A balanced ration has three ossential features. It must supply tho correct amount of bulk —oxces6 and deficiency are both undesirable. It must supply sufficient protein and sufficient starch equivalent. A slight excess of these docs no harm. When these three are adjusted to suit the animal, tho figures in tho column “starch equivalent” in Table I. can be used to compare foods on a cash basis. Thus, 301 b of straw and 101 b of oats each 6upply 61b of starch equivalent, but have not the same feeding value, nor again can 71b of oats be replaced by 61b of barley, although the starch equivalents of both these two amounts aro identical. Used properly linseed has twice tho value of oats per ton; improperly used it is dangerous. PURCHASE OF FEEDS.

For the purpose of purchasing feeds the figures in Table I. are dependable, and it is for this purpose that starch equivalents aro most extensively used. Since tho figures in tho column “starch equivalent” in Table I. all refor to the starch value of 100 pounds of feed, it is obvious that wo can make ueo of these figures to compare prices of different feeds. Thus, 100 pounds of oats with a. starch equivalent of 60 should bo half as valuable as 100 pounds of linseed with a starch equivalent of 120. This process of comparison is used in other countries, and the normal practice is to divide the pneo per ton by the starch equivalent figure. This gives tho value of 1 per cent, of starch equivalent in one ton and is spoken of as tho unit value. Thus oats at £9 per ten has a unit valuo of 180 over 60 equals 3s, and linseed at £ls per ton lias a unit value of 300 over 120 equals 2s 6d. It should bo romombered that all figures should be corrected to a ton of 22401 b before comparisons are made. In the following table different values are taken from oats and other feeds compared with them—using these unit values : Table Showing Comparative Values Per Ton of Different Feeds Based on Varying Prices of Oats. b Oats At

These values are based on experiments with cattle and sheep, but not with norscs and pigs, and the figures are subject to the same limitotions as those in the previous table.

There are several interesting points in this table: —

From the buyer’s point of view the current buying prices of popular feeds, such as oats, oatsheaf chaff, and roots, are in fair agreement with the prices here listed for these feeds, when oats can be bought for 3s 6d per bushel. They aro the highest priced feeds because they are satisfactory, they can be used for alt classes of stock, and* their uso is well understood. Feeds that have only a limited use, such as straws, feeds that are only occasionally used or whoso use requires special care wheat, maize, barley, linseed, pollard, bran —have a current market price below the listed price levels set by oats at 6d per bushel. Barley, maize, meat meal, bran, and pollard arc at present below' the 2s 6d level of oats, anti linseed is nearer the Is 6d level. Even wheat, although used for human consumption, is cheaper to buy at 5s as a stock food than oats at 3s 6d. Molasses ahd linseed cake are high in price, but these have a dietetic value which may in some cases justify their purchase. Consider next the feeds that are bought to feed in the paddock, such as grass and turnips, at say 4d per head per week. A sheep eats about 111 b of starch equivalent per week, and at this rate 1 ton of tuinips lasts nine w’eeks, a ton of swedes fifteen weeks, a ton of green oats seventeen, a toil of ordinary pasture twenty-two, and a ton of Italian rye twenty-seven weeks. On this basis turnips aro worth 3s Id per swedes ss, oats 6s, grass 7s 3d, and Italian rye 9s 2d per ton. Comparison of those figures with those in Table 11. show's that the value per ton of these feeds is less than half their value w'hcri oats cost Is 6a per bushel. Sheep are fed on such feeds for only a few T w r eeks of the year, and on grass for the rest of tho year. A ewe producing a fat lamb costs for grazing about 6s per year, and sinco she eats about three tons of grass, tho grass costs about 2s 6d per ton. Table it shows that where oats are Is 6d per bushel, averago pasture is worth 15s per ton, though actually it costs only 2s 6d—in other words, grazing is undoubtedly the cheapest method of sheep feeding. From tho grower’s point of view also, Table 11. is also worthy of study. If the production costs of green and root crops are 30s per acre, 10 tons of turnips 6 tons of swedes, 5 tons of green oats and 3 tons of Italian Rye to the acre are required to pay for tho crop by grazing sheep at 4d por head per week. A turnip crop of 60 tons must be very payable, but yielding crops of green feed must be debited to accounts other than AT T?vr f rc YIELDS OF STARCH EQUIVALENTS PER ACRE. It is informative to set out in tabular form the yield of starch equivalent per acre from tho common crops of stated

y ‘ elU - TABLE 111 Lbs weight

This table can be misleading if it is assumed that all tho above yields are obtainable on any given class of land. Yields in tho first half of the table are taken from the Year Book, and are average yields in Canterbury. The lower half of the table may represent yields on good land round the college, but again it is not intended that the yield per acre of one crop is equivalent to the yield of another crop. Every farmer must put in his own yield and cost and then the table is useful. Further it is not suggested that because a crop is profitable that euch a crop can be grown to the exclusion of others. Table 111 does not admit of generalisations, but there are two points of New Zealand practice that might be reviewed in the light of information derived from it. First, tlic universal use of oats as a Horse feed in New Zealand; in some other countries mixtures of barley, peas, beans, hay, or wlieaten chaff aro used almost as exclusively as oats aro here, and it is possible that tho=e feeds may cost less to produce than oats do. Next, 'on the North Island dairy farms grass is almost exclusively used. Where 80 tons of mangels can bo grown per acre it is difficult to imagine a crop that produces starch equivalent at a cheaper rate. Provided that mangels can bo turned into human food by stock _ as efficiently as grass is, there is a certainty that the net, per acre production from mangels must bo better even than that from grass, and the reports of occasional farmers that are exploiting this root crop, especially for the winter feeding of pigs, are among the most promising aspects of the pig industry. . In tho past, adequate consideration has not been given to tho yield of starch equivalent per acre and its production cost. If it had, many of our present practices might bo modified —as they might still be if this new point of view is taken. Tho actual compounding of rations in the light of the information presented here will bo dealt with in a later Bulletin.

Roots— p.c. p.c. p.c. Mangolds, whito ... 11.5 0.7 70 5.8 Mangolds, yellow and red 18.0 0.7 70 6.8 Swedes 11.5 1.1 85 7.3 Turnips 8.5 0.6 77 4.4 Potatoes 24.0 1.1 100 18.0 Artichokes 20.0 1.0 92 17.0 Carrots 15.0 0.8 87 8.8 Grass, etc. — Avorago pastures Perennial rye 20.0 2.5 91 11.2 25. C 1.8 81 10.6 Italian rye 31.0 2.1 76 13.7 Cocksfoot. 27 1.5 75 9.8 Whito clover 19.0 2.8 88 8.8 Red clover 19.0 2.5 86 10.2 Lucerne 24.0 3.2 79 9.1 Green oats 10.0 1.7 89 8.5 Green harley 19.0 1.8 80 9.6 Rape 15.0 2.0 87 6.9 Hay and Straws— Oatsheaf chat! 86.0 3.8 65 36.0 Oats and tares 84.0 6.5 67 30.0 Avorago hay 86.0 5.4 67 31.0 Oat straw 86.0 1.0 45 19.0 Wheat straw 86.0 0.1 33 12.0 Parley straw 86.0 0.8 46 20.0 Wheat or oat cavings 86.0 1.6 74 26.0 Grains, etc. — Oats 87.0 8.0 95 60.0 Barley 86.0 6.5 98 71.0 Wheat 87.0 10.2 96 72.0 Maize 87.0 7.1 100 82.0 86.0 19.4 98 69.0 Linseed 93.0 19.4 99 120.0 Bye-products— Pollard 86.0 13.4 86 65.0 Bran 86.0 11.2 77 45.0 Browers’ grains 24.0 3.7 86 12.7 Malt culms 88.0 18.5 75 38.0 Meat meal 93.0 5.0 100 9o,0 Molasses 80.0 1.1 87 51.0 Linseed cako 92.0 2.8 97 75.0 Skim milk 9.4 4.3 100 8.3 Whey b.b O.b 100 6.1

1 6 2 6 3 6 per bus. per bus. per bus. Feeds — 8. 84 d. 0 s. 140 d. 0 s. 196 Cl. 0 Mangels (white) 8 0 18 6 19 0 Mangels (rod and yellow) Swedes 9 10 6 6 3 0 16 17 10 0 0 3 2! 24 14 0 0 6 Potatoes Avorago pasture Italian ryegress Red clover Rape Green oats Oat sheaf chaff Average hay ... 25 15 19 15 9 12 50 43 26 0 6 6 0 6 0 0 0 0 42 26 32 24 16 20 84 73 44 0 0 0 0 0 0 0 0 0 59 36 45 33 22 28 118 101 62 0 6 0 3 6 0 0 0 0 Wheat straw ... 16 Cavings 25 Barley (per ton) 100 9 0 0 28 61 166 0 0 0 39 85 232 9 0 0 Barley (per bus.) Wheat (per ton) z 101 3 0 3 168 0 236 0 Wheat (per bus.) Maize (per ton) 2 115 8 0 191 5 0 268 0 Maize (per bus.) Peas (per ton) . Peas (per bus.) Linseed Pollard Bran 3 96 2 168 91 63 2 0 7 0 0 0 5 161 4 280 152 105 0 4 0 0 0 226 6 392 212 147 0 0 0 0 0 Brewer’s grains Malt culms (dry) Meat meal Molasses 17 53 133 70 100 9 0 0 0 0 30 89 222 116 175 0 0 0 0 0 41 124 310 163 245 0 0 0 Oi 0 1 11 6 19 4 Whey 8 6 14 3 20 0

Crop. Oats Oatsheaf chaff .. Wheat Wheat chaff Barley Assumed yield per acre. 40 bus. 1.58 tons 30 bus. . 1.8 tons 46 bus. 30 bus. of starch equivalent per acre. 960 1274 1260 1411 1666 1260 Linseed 7 cat. . 6.4 tons 940 1600 (2 sheep per aero or 1 cow per two acres) 6 tons 827 Turnips Swedes Mangels 20 tons 15 tons 30 tons . 5 tons 1971 2454 4369 2016 1J tons 873 Italian ryo Green oats 3 tons 3 tons 711 570