500 



liberal jiroportioiis of protein in the food. Tliey accord with a very large 

 amount of experiment and experience on both sides of the Atlantic in 

 i iidicating that in regions where the farmer must buy concentrated foods, 

 and especially where he must use artificial fertilizers, the advantage of 

 feeding stuffs rich in protein is very mariced. 



The reason for this advantage is twofold. The protein is essential 

 for the nutrition of the animals, and Avith it the carbohydrates and fats 

 of other feeding stufts can be profitably utilized. The nitrogenous 

 feeding stufts are an economical source of nitrogen and i)hosi>horic acid 

 formamire. Unfortunately these principles are not always appreciated 

 at their full value. Even in those parts of the United States where 

 the high value of land and nearness to market call for intensive farm- 

 ing, where nitrogenous and phosphatic fertilizers are largely used, and 

 oil cake, bran, corn meal, and like concentrated foods are a necessity, 

 comparatively few farmers or dairymen use such quantities of protein 

 as accurate experiment implies would be profitable. (3f course a great 

 deal of investigation will be needed to show just what proportions will 

 be most advantageous for ditferent classes of animals and under the 

 Midely different conditions which prevail in the United States, but 

 there is no doubt that one of the essential reforms in our feeding prac- 

 tice will be in using more nitrogenous feeding stuffs. — [W. O. A.] 



The experiments above referred to furnish another illustration of the 

 futility of drawing general conclusions from a single trial or a series of 

 trials, and the necessity of numerous repetitions of the same experiment. 



In the experiments of series E (page 565) the question Avas spe- 

 cific and narrow — the effect of the addition of non-nitrogenous food to a 

 ration rich in nitrogen; in other words the old question of wide vs. 

 narrow rations. Instead of depending on two or three cows, as is often 

 done, eight were used. They were all fed alike during each of five test 

 ])eriods, with transition periods between, the food being different in the 

 different test periods. The result was a clear gain of live weight with 

 the narrower and loss with the wider ration, while the only change in 

 milk yield was that which naturally came with advance of the period 

 of lactation. The same experiments were made in another ]>lace with 

 another lot of cows, and with results practically identical. The infer- 

 ence which seemed to be so clearly Avarranted by the first series was 

 strikingly confirmed in the second. The same experiments were 

 rci>eated in a third place with six cows, but the results were the opposite 

 of those of the first two series in respect to both change in live weight 

 and milk yield. The cows of the third series lost weight with the nar- 

 rower and gained with the wider ration, and the milk yield rose Avitli 

 increase of non-nitrogenous food. There Avere slight differences in the 

 kinds of food materials in the three cases, but not such as to account 

 for the difference in result. The most plausil)le hy])othesis is that the 

 cows in the last case were in poor condition. — [W. O. A.] 



