The Stock-Feeder's Manual Part 2

The food of human beings and of the lower animals who inhabit cold countries is nearly exclusively composed of animal substances.

The flesh, fat, and oil of animals occupy less s.p.a.ce than do the corresponding elements of vegetables; consequently the nutriment they afford is more concentrated, and a larger quant.i.ty can be stowed away without inconvenience in the stomach. The heat-forming const.i.tuents of these substances const.i.tute not only the chief part of their bulk, but they are also capable of evolving a greater amount of heat than any other of the respiratory elements. One pound of dry fat will develop as much heat as two and a half pounds of dry starch, and the fattest flesh includes four times as much plastic materials as rice. The diet of people all over the world, unless under circ.u.mstances which prevent the gratification of the natural appet.i.te, establishes the intimate relation which subsists between cold and food. The appet.i.te of man is at a minimum at the Equator, and at a maximum within the Arctic circle. The statements as to the voracity of Hottentots and Bosjesmans, recorded in the narratives of travellers, do not in the slightest degree affect the general rule that more is eaten in cold climates than in hot regions.

These are mere records of gluttony, and it would not be difficult to find parallel cases in our own country. Gluttony is an abnormal appet.i.te, and the greater part of the food devoured under its unnatural, and generally unhealthy stimulus is not applied to the wants of the body.

The bodies of animals are heated ma.s.ses of matter, and are subject to the ordinary laws of _radiation_. Every substance radiates its heat, and receives in return a portion of that emitted from surrounding bodies. If two bodies of unequal temperature be placed near each other, the warmer of the two will radiate a portion of its heat to the colder, and will receive some of the heat of the latter in return; but as the warmer body will emit more heat than it will receive, the result will be, that after a time, the length of which will depend on the nature of the bodies, both will acquire the same temperature. In very warm climates the bodies of animals derive from the sun, and from the heated bodies surrounding them, more heat than they give in return; and were it not for their internal cooling apparatus, which I have described, the heat so absorbed would prove fatal. In every climate, on the contrary, where the temperature is lower than 98, or "blood heat," the bodies of animals lose more heat by radiation than they receive by the same means. The philosophy of the _clothing_ of men and the _sheltering_ of the lower animals is now evident. It is not only necessary that heat should be developed within the body, but also that its wasteful expenditure should be prevented. The latter is effected by interposing between the warm body and the cold air some substances (such as fur or wool) which do not readily permit the transmission of heat--_non-conductors_ as they are termed. The close down of the eider duck is destined to protect its bosom from the chilling influence of the icy waters of the North Polar Sea, and the quadrupeds of the dreary Arctic Circle are sheltered by thick fur coverings from the piercing blasts of its long winter.

_Fat Equivalents._--Whilst it is quite certain that neither nerves nor muscles can be elaborated exclusively out of fat, starch, sugar, or any other non-nitrogenous substance, it is almost equally clear that fat may be formed out of nitrogenous tissue. The quant.i.ty of fat, however, which is produced in the animal mechanism, from purely nitrogenous food appears to be relatively very small. No animal is capable of subsisting solely on muscle-forming materials, no matter how abundantly supplied.

The food of the Carnivora contains a large proportion of fat, and the nutriment of the Herbivora is largely made up of starch and other fat-formers. Dogs, geese, and other animals fed exclusively upon alb.u.men or white of egg rapidly decreased in weight, and after presenting all the symptoms of starvation, died in three or four weeks.[8] The fat of the bodies of the Carnivora is almost entirely formed--and probably with little if any alteration--from the fatty const.i.tuents of their food.

Herbivorous animals, on the contrary, derive nearly all their fat from starch, sugar, gum, cellulose, and other non-nitrogenous, but not fatty, materials.

Although starch is convertible into fat, it is not to be understood that a pound weight of one of these bodies is equivalent to an equal quant.i.ty of the other. During the conversion of starch into fat, the greater number of its const.i.tuent atoms is converted into water and carbonic acid gas. The greater number of the more important metamorphoses of organised matter, which take place in the animal organum, is the result of either oxidation or fermentation: in the conversion of starch or sugar into fat or oil, both of these processes, it is stated, take place; a portion of the hydrogen is converted by oxidation into water, and by fermentation carbonic acid gas is formed, which removes both oxygen and carbon. Perhaps in the formation of fat fermentation is alone employed--a portion of the oxygen being removed as water, and another portion as carbonic acid. The chief difference between the ultimate composition of starch and fat is, that the latter contains a much larger proportion of hydrogen and carbon. The knowledge of the exact quant.i.ty of starch required for the formation of a given amount of fat is of importance in enabling us to estimate the relative feeding value of both substances. Certain difficulties stand in the way of our acquiring an accurate knowledge on this point. Not only are there several distinct kinds of fat, but the precise formula, or atomic const.i.tution of each, is as yet veiled in doubt. There are three fats which occur in man and the domesticated animals, and in vegetables. These are stearine, margarine, and oleine. The relative proportions of these vary in each animal: thus, in man and in the goose margarine is the most abundant fat, whilst oleine[9] exists in the pig in a greater proportion than in man, the sheep, or the ox. The composition of the animal fats does not, however, vary much; and this fact, together with other considerations, have led chemists to a.s.sume that two-and-a-half parts of starch are required for the production of one part of the mixed fats of the different animals. Grape sugar and the pectine bodies--substances which form a large proportion of the food of the Herbivora--contain more oxygen and hydrogen than exist in starch, and, consequently, are not capable of forming so large an amount of fat as an equal weight of starch. We may a.s.sume, then, that 250 parts of starch, 275 parts of sugar, or 3 parts of the pectine bodies, are equivalent to 1 part of fat.

SECTION IV.

RELATION BETWEEN THE COMPOSITION OF AN ANIMAL AND THAT OF ITS FOOD.

I have already stated that the results of the admirable investigations of Lawes and Gilbert prove that the non-nitrogenous const.i.tuents of the carca.s.ses of oxen, sheep, and pigs exceed in weight their nitrogenous elements. This fact is suggestive of many important questions. What relation is there between the composition of an animal and that of its food? Should an animal whose body contains three times as much fat as lean flesh, be supplied with food containing three times as much fat-formers as flesh-formers? To these questions there is some difficulty in replying. There _is_ a relationship between the composition of the body of an animal and that of its food; but the relationship varies so greatly that it is impossible to determine with any degree of accuracy the quant.i.ty of fat-formers which is required to produce a given weight of fat in animals, taken _in globo_. If, however, we deal with a particular animal placed under certain conditions, it is then possible to ascertain the amount of fat which a given weight of non-plastic food will produce. For the greater part of our knowledge on this point, as on so many others, in the feeding of stock, we are indebted to Lawes and Gilbert. In the case of sheep fed upon fattening food these inquirers found that every 100 lbs. of dry[10] non-nitrogenous substances consumed by them produced, on an average, an increase of 10 lbs. in the weight of their fat. In the case of pigs, also, supplied with food, the proportion of non-nitrogenous matters appropriated to the animal's increase was double that so applied in the bodies of the sheep. As the food supplied to these animals contained but a very small proportion of ready-formed fat, it was inferred that four-fifths of the fat of the increase was derived from the sugar, starch, cellulose, and pectine bodies.

These tables exhibit in a condensed form the results of one of the elaborate series of experiments in relation to this point carried out by Lawes and Gilbert:--

ESTIMATED AMOUNT OF CERTAIN CONSt.i.tUENTS STORED UP IN _INCREASE_, FOR 100 PARTS OF EACH CONSUMED IN FOOD BY FATTENING SHEEP.

+-------------------------------------------------------- KEY: A.--No. of Animals.

B.--Mineral matter (ash).[11]

C.--Nitrogenous compounds (dry).

D.--Non-nitrogenous substance.

E.--Total dry substance.

--------------------+------------------------------------+------------------- Amount of each Cla.s.s in Increase for 100 of the same GENERAL PARTICULARS OF THE EXPERIMENTS. consumed in Food.

--------------------+---+---------+-------------+--------+----+----+----+---- Description of Fattening Food. -------------+-------- Given Given in limited ad BREED. A. Duration. quant.i.ty. libitum. B. C. D. E.

--------------------+---+---------+-------------+--------+----+----+----+---- Cla.s.s I.

--------------------+---+---------+-------------+--------+----+----+----+---- wks. dys. Oilcake and Swedish clover chaff. turnips. Cotswolds 46 19 5 " " 398 443 116 960 Leicesters 40 20 0 " " 315 339 120 948 Cross-bred wethers 40 20 0 " " 324 360 116 931 Cross-bred ewes 40 20 0 " " 325 360 118 940 Hants Downs 40 26 0 " " 340 428 103 849 Suss.e.x Downs 40 26 0 " " 330 416 103 844 --------------------+---+---------+-------------+--------+----+----+----+---- Means 339 391 113 912 =========================================================+====+====+====+==== Cla.s.s III.--(Series 1.) --------------------+---+---------+-------------+--------+----+----+----+---- Swedish turnips. Hants Downs 5 13 6 Oilcake. " 416 401 111 933 5 13 6 Oats. " 573 707 100 945 5 13 6 Clover chaff. " 398 744 90 849 --------------------+---+---------+-------------+--------+---------+----+---- Means 462 617 100 909 =========================================================+====+====+====+==== Cla.s.s IV.--(Series 2.) --------------------+---+---------+-------------+--------+----+----+----+---- Clover chaff. Hants Downs 5 19 1 Oilcake. " 169 220 63 507 5 19 1 Linseed. " 181 232 62 519 5 19 1 Barley. " 175 282 57 500 5 19 1 Malt. " 146 217 53 461 --------------------+---+---------+-------------+--------+----+----+----+---- Means 168 238 59 497 =========================================================+====+====+====+==== Cla.s.s V.--(Series 4.) --------------------+---+---------+-------------+--------+----+----+----+---- Mangolds Hants Downs 4 10 0 Barley ground " 380 565 98 891 5 10 0 Malt, ground, " 404 618 104 949 & malt dust. 4 10 0 Barley ground " 372 635 89 828 and steeped. 4 10 0 Malt, ground " 295 434 93 823 and steeped, & malt dust. 5 10 0 Malt, ground, " 346 546 91 825 & malt dust. --------------------+---+---------+-------------+--------+----+----+----+---- Means 359 560 95 863 ---------------------------------------------------------+----+----+----+---- Means of all 327 441 94 806 =========================================================+====+====+====+====

ESTIMATED AMOUNT OF CERTAIN CONSt.i.tUENTS STORED UP IN _INCREASE_, FOR 100 OF EACH CONSUMED IN FOOD, BY FATTENING PIGS.

+----------------------------------------------------------------- KEY: A.--No. of Animals.

B.--Mineral matter (ash).

C.--Nitrogenous compounds (dry).

D.--Non-nitrogenous substance.

E.--Total dry substance.

F.--Fat.

-----------+----------------------------------------+------------------------ Amount of each Cla.s.s in Increase for GENERAL PARTICULARS OF THE EXPERIMENTS. 100 of the same consumed in Food.

--+--------+----------------------------------------+----+-----+----+----+--- Description of Fattening Food. --------------------+------------------- Given in Given A. Duration limited quant.i.ties. ad libitum. B. C. D. E. F.

==+========+====================+===================+====+=====+====+====+=== The a.n.a.lysed "Fat Pig."[12]

--+--------+----------------------------------------+----+-----+----+----+--- weeks 1 10 Mixture of bran 1, bean and lentil-meal 266 776 176 149 405 2, and barley-meal 3 parts, ad libitum ==+========+========================================+====+=====+====+====+=== Series I.

--+--------+--------------------+-------------------+----+-----+----+----+--- 3 8 None. Bean & lentil-meal. 068 488 253 175 621 3 " Indian-meal. " 186 639 237 179 477 3 " Indian-meal and bran " 033 502 211 161 362 3 " None. Indian meal. 209 928 209 186 300 3 " Bean and lentil-meal " 099 918 209 184 324 3 " Bran. " 235 1210 203 187 300 3 " Bean, lentil-meal, " 271 1003 213 185 307 and bran. " +------------------- 3 " Bean, lentil-meal, Indian-meal, bran, 022 565 211 168 362 ad libitum. --+--------+----------------------------------------+----+-----+----+----+--- Means 074 782 218 178 382 ====================================================+====+=====+====+====+=== Series II.

--+--------+--------------------+-------------------+----+-----+----+----+--- 3 8 None. Bean & lentil-meal. 320 312 265 182 801 3 " Barley-meal. " 016 465 192 147 575 3 " Bran. " 016 399 212 152 547 3 " Barley-meal and bran " 075 457 201 156 514 3 " None. Barley-meal. 056 1009 185 169 574 3 " Bean and lentil-meal " 053 657 211 175 620 3 " Bran. " 049 979 189 169 506 3 " Bean, lentil-meal, " 433 449 227 180 578 and bran. +------------------- 6 " Mixture of bran 1, barley-meal 2, and 027 565 204 161 495 bean lentil-meal 3 parts, ad libitum. 6 " Mixture of bran 1, bean lentil-meal 2, 158 810 211 176 515 barley-meal 3 parts, ad libitum. --+--------+----------------------------------------+----+-----+----+----+--- Means 059 610 210 167 572 ====================================================+====+=====+====+====+=== Series III.

--+--------+--------------------+-------------------+----+-----+----+----+--- 4 8 Dried Cod Fish. Bran & Indian-meal 106 506 243 181 315 (equal parts). 4 " " Indian-meal. 026 816 256 209 352 --+--------+--------------------+-------------------+----+-----+----+----+--- Means 066 661 249 195 333 ====================================================+====+=====+====+====+=== Series IV.

--+--------+--------------------+-------------------+----+-----+----+----+--- 3 10 Lentil-meal & bran. Sugar. 307 930 194 169 3 " " Starch. 318 936 194 169 3 " " Sugar & starch. 406 1078 177 161 +------------------- 3 " Lentils, bran, sugar, starch, ad libitum 480 996 187 165 --+--------+----------------------------------------+----+-----+----+---- --- Means 378 985 188 166 ----------------------------------------------------+----+-----+----+----+--- Means of all 058 734 212 173 472 ====================================================+====+=====+====+====+===

The larger appropriation of the non-nitrogenous const.i.tuents of its food by the pig, as compared with the sheep, must not be attributed solely to its greater tendency to fatten, but partly to the far more digestible nature of the food supplied to it.

SECTION V.

RELATION BETWEEN THE QUANt.i.tY OF FOOD CONSUMED BY AN ANIMAL, AND THE INCREASE IN ITS WEIGHT, OR OF THE AMOUNT OF ITS WORK.

The manifestations of that wondrous and mysterious principle, _life_, are completely dependent upon the decomposition of organised matter. Not an effort of the mind, not a motion of the body, can be accomplished without involving the destruction of a portion of the tissues. In a general sense we may regard the fat of the animal to be its store of fuel, and its lean flesh to be the source of its motive power. As the evolution of heat within the body is proportionate to the quant.i.ty of fat consumed, so also is the amount of force developed in the animal mechanism in a direct ratio to the proportion of flesh decomposed.

The quant.i.ty of fat burned in the body is estimated by the amount of carbonic acid gas expired from the lungs and perspired through the skin; the proportion of flesh disorganised is ascertained by the quant.i.ty of urea eliminated in the liquid egesta. The amount of urea excreted daily by a man is influenced by the activity of his mind, as well as by that of his body. A man engaged in physical labor wears out more of his body than one who does no work; and a man occupied in a pursuit involving intense mental application, consumes a greater proportion of his tissue than the man who works only with his body.[13] In each of these cases, there is a different amount of tissue disorganised, and consequently a demand for different amounts of food, with which to repair the waste.

But all the food consumed by a man is not devoted to the reparation of the tissue worn out in the operations of thinking and working. A human being whose mind is a perfect blank, and who performs no bodily work, excretes a large quant.i.ty of urea, the representative of an equivalent amount of worn-out flesh. In fact the greater part of the food consumed by a man serves merely to sustain the functions of the body--the circulation of the blood--the action of the heart--the movements of the muscles concerned in respiration--in a word, the various motions of the body which are independent of the will. According to Professor Haughton, about three-fourths of the food of a working man of 150 lbs. weight, are used in merely keeping him _alive_, the remaining fourth is expended in the production of mechanical force, const.i.tuting his daily toil.

In the nutrition of the lower animals, as in that of man, the amount of food made use of by a particular individual depends upon its age, its weight, the amount of work it performs, and probably its temper. As three-fourths of the weight of the food of a laboring man are expended in merely keeping him alive, it is obvious that the withholding of the remaining fourth would render him incapable of working. An amount of food which adequately maintains the vital and mechanical powers of three men, serves merely to keep four alive. It is the same with the horse, the ox, and every other animal useful to man: each makes use of a certain amount of food, _for its own purposes_; all that is consumed beyond that is applied for the benefit of its owner. Let us take the case of two of our most useful quadrupeds--the horse and the ox. The horse is used as an immediate source of motive power. For this purpose food is supplied to it, the greater portion of which is consumed in keeping the animal alive, and the rest for the development of its motive power. Abundance of food is as necessary to the natural mechanism, the horse, as fuel is to the artificial mechanism, the steam-engine.

In each case the amount of force developed is, within certain limits, proportionate to the quant.i.ty of vegetable or altered vegetable matter consumed. The greater portion of the ox's food is also consumed in keeping its body alive, and the rest, instead of being expended in the development of motive power, acc.u.mulates as surplus stores of flesh, which in due time are applied to the purpose of repairing the organisms of men. It is evident then, that the greater sufferer from the deficient supply of food to animals is their owner. That they cannot be _taught_ to _fast_ is a fact which does not appear very patent to some minds.

The man who sought by gradually reducing the daily quantum of his horse's provender to accustom it to work without eating, was justly punished for his ignorant cruelty. The day before the horse's allowance was to be reduced to pure water, and when its owner's hope appeared certain of speedy realisation, the animal died. There are men who act almost as foolishly as the parsimonious horse owner in this fable did; and who are as properly punished as he was. Such men are to be found in the farmers who overstock their sheep pastures, and whose "lean kine"

are the _laughing stock_ of their more intelligent neighbours.

The weight of a working full-grown horse does not vary from day to day, as the weight of its egesta is equal to that of its food.

The desideratum in the case of the working animal is that its food should be as thoroughly decomposed as possible, and the force pent up in it liberated within the animal's body: as an ox, on the contrary, increases in weight from day to day, it is desirable that as little as possible of its food should be disorganised. The wasteful expenditure of the animal's fat may be obviated by shelter, and the application of artificial heat: the r.e.t.a.r.dation of the destruction of its flesh is even more under our control; for, as active muscular exertion involves the decomposition of tissue, we have merely to diminish the activity of the motions which cause this waste. This, in practice, is effected by stall-feeding. Confined within the narrow boundaries of the stall, the muscular action of the animal is reduced to a minimum, or limited to those uncontrollable actions which are conditions in the maintenance of animal life.

The proportion of the food of oxen, sheep, and pigs, which is consumed in maintaining their vital functions, has not been accurately ascertained; probably, as in the case of man, it is strictly proportionate to the animal's weight. We can determine the amount of plastic food consumed by an animal during a given period: we can ascertain the increase (if any) in the weight of its body; and finally, we can weigh and a.n.a.lyse its egesta. With these data it is comparatively easy to ascertain the quant.i.ty of food which produced the increase in the animal's weight; but they do not enable us to determine the amount expended in keeping it alive, because the egesta might be largely made up of unappropriated food--organised matter which had done no work in the animal body. When we come to know the precise quant.i.ty of nitrogen, in a purely, or nearly pure, mineral form[14] excreted by an animal, then we shall be in a position to estimate the proportion of its food expended in sustaining the essential vital processes which continuously go on in its body. But although we are in ignorance as to the precise quant.i.ty of flesh-formers expended in keeping the animal alive, we know pretty accurately the amount which is consumed in producing a given weight of its flesh, or rather in causing a certain increase in its weight. This knowledge is the result of numerous investigations, of which by far the most valuable are those of Lawes and Gilbert. These experimenters found that fattening pigs stored up about 7-1/2 per cent. of the plastic materials of their food, whilst sheep acc.u.mulated somewhat less than 5 per cent. That is, 92-1/2 out of every 100 lbs.

weight of the nitrogenous food of the pig, and 95 out of every 100 lbs.

of that of the sheep, are eliminated in the excretions of those animals.

It appears from the results of Lawes and Gilbert's experiments, that pigs store up in their _increase_ about 20 per cent., sheep 12 per cent., and oxen 8 per cent. of their (dry) food. The relative increase of the fatty, nitrogenous, and mineral const.i.tuents whilst fattening, are shown in this table.

---------------------+------------------------------------------------- Estimated per cent. in Increase whilst Fattening.

CASES. +--------+-----------+-----------+---------------- Mineral Nitrogenous matter matter Fat (dry). Total dry (ash). (dry). substance.

---------------------+--------+-----------+-----------+---------------- Average of 98 oxen 147 769 662 754 Average of 348 sheep 180 713 704 7953 Average of 80 pigs 044 644 715 7840 ---------------------+--------+-----------+-----------+----------------

The quant.i.ty of food consumed daily by an animal is, as might be expected, proportionate to the weight of its body. The pig consumes, for every 100 lbs. of its weight, from 26 to 30 lbs. of food, the sheep 15 lbs., and the ox 12 to 13 lbs. These figures and the statements which I have made relative to the proportions of fat and plastic elements in the animals'

bodies, apply to them in their fattening state, and when the food is of a highly nutritious character. The calf and the young pig will make use--to cause their increase--of a larger portion of nitrogenous matters. The sheep, however, being early brought to maturity, will, even when very young, store up the plastic and non-plastic const.i.tuents of its food, in nearly the same relative proportions that I have mentioned.

As it is the food taken into the body that produces heat and motion, it might at first sight appear an easy matter to determine the amount of heat or of motion which a given weight of a particular kind of food is capable of producing within the animal mechanism. But this performance is not so easy a task as it appears to be. In the first place, all of the food may not be perfectly oxidised, though thoroughly disorganised within the body; secondly, as animals rarely subsist on one kind of food, it is difficult, when they are supplied with mixed aliments, to determine which of them is the most perfectly decomposed. But though the difficulties which I have mentioned, and many others, render the task of determining the nutritive values of food substances difficult, the problem is by no means insoluble, and, in fact, is in a fair way of being solved. Professor Frankland, in a paper published in the number of the _Philosophical Magazine_ for September, 1866, determines the relative alimental value of foods by ascertaining the quant.i.ty of heat evolved by each when burned in oxygen gas. From the results of these researches he has constructed a table, showing the amount of food necessary to keep a man alive for twenty-four hours. The following figures, which I select from this table, are of interest to the stock-feeder:--

Weight necessary to sustain a man's life for twenty-four hours.

Kinds of Food. Ounces.

Potatoes 134 Apples 207 Oatmeal 34 Flour 35 Pea Meal 35 Bread 64 Milk 212 Carrots 256 Cabbage 318 b.u.t.ter 18 Lump Sugar 39

These figures show the relative calefacient, or heat-producing powers of the different foods named _outside_ the body; but there is some doubt as to their having the same relative values when burned _within_ the body.

The woody fibre of the carrots and cabbages is very combustible in the coal furnace, but it is very doubtful if more than 20 or 30 per cent. of this substance is ever burned in the _animal furnace_. However, such inquiries as those carried out by Frankland possess great value; and tables constructed upon their results cannot fail to be useful in the drawing up of dietary scales, whether for man or for the inferior animals.

I may here remark, that in my opinion the nutritive value of food admits of being very accurately determined by the adoption of the following method:--

1. The animal experimented upon to be supplied daily with a weighed quant.i.ty of food, the composition and calefacient value of which had been accurately determined. 2. The gases, vapors, and liquid and solid egesta thrown off from its body to be collected, a.n.a.lysed, and the calefacient[15] value of the combustible portion of them to be determined.

3. The increase (if any) of the weight of the animal to be ascertained.