394 FOOD AND FEEDING. 



that the numbers assigned by different authorities are 42, 57, and 

 108 ; and M. Perrault, "rom direct experiment, found the equivalent 

 number of colza-cake U be 36, analysis giving 23 as the theoretical 

 Qumber. On the whole it may be said, that in practice, the results, 

 although sufficiently different, still agree in ascribing to oil-cake a 

 nutritive value inferior to that indicated by theory. 



I have thought it important to insist upon the discrepancy which 

 is here so conspicuous between the inferences from chemical analy- 

 sis and those arrived at by experience, because it appears to me to 

 depend upon a particular circumstance which frequently intervenes 

 in the feeding of cattle, and which it is very important to be aware 

 of: I allude to the influence of the bul/c of the allowance of food. 



Vegetable food of every description has nearly the same specific 

 gravity ; it is but little above that of water ; the bulk of the allow- 

 ance therefore depends upon its weight. Every one will conceive 

 that a ration of highly nutritious food, which for this reason would 

 occupy but little space, would be open to many objections. A cart- 

 horse, of the ordinary size, from what I have myself repeatedly 

 observed, requires from 26 to 33 lbs. of solid food, and about the 

 same quantity of water in the twenty-four hours. The bulk of this 

 allowance, when masticated and brought to the state in which it is 

 swallowed, will be upwards of 9j cubic feet. Now, if for the ordi- 

 nary forage, one that is five times more nutritious were substituted, 

 oil-cake, for example, the dry ration, according to the rule of equiv- 

 alents, would be reduced to 6.6, or a little more than l\ lbs., and its 

 hulk would not surpass 5| cubic feel. The animal would not feel 

 satisfied with this allowance, it would still feel hungry, or the food 

 given in such a concentrated shape would disagree with it. If, on 

 the contrary, a forage that is very little initrilious were substituted, 

 such as wheat-straw, the equivalent of which is 500, the ration 

 would then become too bulky to be eaten in the course of a day, it 

 would amount to as many as 165 lbs. It is therefore absolutely ne- 

 cessary to take into consideration the bulk of the food allowed : the 

 belly must of necessity be filled ; whatever the nutritive value of 

 any article, it miist be given in a certain quantity ; and in the case 

 of such a substance as oil-cake, the consumption to fill the stomach 

 would cease to be in any kind of proportion to the nutritive equiv- 

 alent. 



It is extremely difficult t(» appreciate the precise limits beyond 

 which an article of forage or a given ration ceases to be nutritious. 

 When a?iy addition is made to an allowance known and admitted to 

 be sufficient, the effect of the extra quantity is scarcely perceptible; 

 so that, in practice, we are apt to fall into the err«>r of estimating at 

 too low a rate the nutritious powers of food given in too large quan- 

 tities. I have had proof of this in a series of experiments on tlio 

 maintenance of a number of milcli-kine. To a cow which was 

 receiving the e(iuivalent of 33 lbs. of meadow-hay in dry fodder and 

 Jerusalem potatoes, an aiidilion was made of 6} lbs. of oil-cake, by 

 ivhich the allowance of nourishment was doubled theoretically ; the 

 animal only ate the half of the cake, however : still, the quality of 



