270 



THE KOTHAMSTED EXPERIMENTS. 



Increase 

 in weight 

 in cattle, 

 sheep, and 

 pigs. 



ing food, consists, weight for weight, of a much larger pro- 

 portion of digestible or convertible constituents, and contains 

 very little effete woody fibre. Thus, whilst the food of oxen 

 and sheep is composed principally of grass, hay, straw, and 

 roots, with a comparatively small proportion of grain, legum- 

 inous seeds, or other concentrated foods, that of the pig con- 

 sists largely of grain or other seeds, which contain a compara- 

 tively small amount of indigestible woody fibre, and a large 

 proportion of starch or other digestible carbohydrate, and 

 nitrogenous matters which are almost entirely in the condition 

 of albuminoids. It is true that the pig consumes also more 

 or less of starchy tubers, or saccharine roots, which contain a 

 considerable proportion of their nitrogen in other forms than 

 albuminoids. But the more rapidly he is fattened, the larger 

 is the proportion in his food of starchy grains, or other 

 ripened seeds. 



Notwithstanding the much more concentrated and digestible 

 character of the food of the fattening pig, he consumes a much 

 larger quantity of dry substance in proportion to his weight 

 than either the ox or the sheep. Under these circumstances 

 he yields much more increase, both in proportion to a given 

 live-weight within a given time, and to a given amount of 

 dry substance of food consumed. This is clearly illustrated 

 in Table 69, p. 287, which shows, as an approximate average, 

 that per 100 lb. live- weight per week, the fattening ox will 

 consume about 12.5 lb. of dry substance of food, and yield 

 about 1.13 lb. of increase ; the sheep will consume about 16 

 lb. of dry substance of food, and yield about 1.76 lb. of in- 

 crease ; whilst the pig, on the other hand, will consume about 

 27 lb. of dry substance of his more concentrated food, and 

 yield about 6.43 lb. of increase. Indeed, compared with oxen 

 or sheep, the liberally fed fattening pig will consume much 

 more food in excess of that required for the respiratory function 

 and for mere maintenance, so that the amounts of non-nitro- 

 genous matters consumed for a given live-weight within a 

 given time represent in less proportion the respiratory require- 

 ments, and in a greater proportion those for increase. 

 Plan of Numerous feeding experiments have been made at Roth- 



ments Cpen ~ amsted witn pig s - In 1850, Series 1, with twelve pens, Series 

 2, also comprising twelve pens, and Series 3, with five pens, 

 and subsequently a fourth Series of four pens, was made. 

 The general plan was to give, in one or more pens, food of 

 high or of low percentage of nitrogen as the case might be, 

 ad libitum ; then in others to give a fixed and limited amount 

 of food of low percentage of nitrogen, and ad libitum a food 

 of high percentage ; or a fixed and limited amount of food of 

 high percentage of nitrogen, and ad libitum a food of low 



