Animal nutrition / [Thomas Barlow Wood].

  • Thomas Barlow Wood
Date:
1924
Catalogue details

Licence: In copyright

Credit: Animal nutrition / [Thomas Barlow Wood]. Source: Wellcome Collection.

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    an animal by 1 lb. of eacli of the three main constituents of feeding stuffs is :— Heat value per lb. Protein ... ... ... ... 2,130 Calories Fat ... ... ... ... 4,000 ,, Carbohydrates ... ... ... 1,707 „ It is obvious that these figures provide a common basis for comparing the values of protein, fat, and carbohydrates. Taking the heat producing value of carbohydrates per lb. as 1, then the relative values of protein per lb. will be 2,130 -j- 1,707 or 1'23, and of fat 4,000 -4- 1,707 = 2'3. Applying these values to a feeding stuff, say linseed cake, it is possible to find the percentage of carbohydrate which will have the same heat producing value as the combined percentages of protein, fat, and carbohydrate shown by the analysis. Thus :— Water Protein Fat ... Carbohydrate Fibre Ash ... Linseed cake. Analysis per cent. 112 * — 29-5 x 123 = 36-5 9-5 x 2-3 = 21-8 35-5 x 1 = 35-5 91 — 5-2 — — 938 A linseed cake of average composition will therefore give out as much heat in the body of an animal as if it contained 93'8 per cent, of carbohydrate and no protein and fat. But it must not be forgotten that when an animal eats a feeding stuff, although the carbohydrates and fat are either converted into fat or lost in the breath of the animal, the nitrogen of the protein and the ash are excreted in the dung and urine and serve to increase the value of the animal’s manure. On this subject refer back to Chemistry of Crop Production, Chapter XIII. This being so, every ton of feed¬ ing stuff purchased will bring onto the farm a certain
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