29 



the same in quality, and differ only in the amount. The object of these 

 experiments is to learn what amounts of different foods may be most 

 profitably fed, when not only the amount, but also the quality of the 

 milk is taken into account. In others, the rations differ in composition, 

 the object being to determine whether an increase or decrease in the 

 proportion of albuminoids, ftit, or starch in the food will cause an in- 

 crease or decrease in the proportion of albuminoids (casein) or fat 

 (butter) in the milk. 



As an example of experiments of the first sort we have a series made 

 in Moeckern, (Vs.-St., 1869, xii, p. 114,*) in which four cows were fed 

 with rations consisting of hay, barley-straw, turnips, and rape-cake. 

 In one period the daily ration consumed contained an average of 19.34: 

 pounds of organic substance per 1,000 pounds live weight ; in the other, 

 22.30 pounds. Each period continued some three weeks, and the milk 

 was carefully measured, and was analyzed nearly every day. 



The increase in the ration, amounting to about 17 per cent., was at- 

 tended by hardly any increase in the amount of milk, although, with the 

 richer feeding, the milk contained a slightly larger percentage of organic 

 substance. The composition of the latter was essentially unaltered. 



In another series performed at Moeckern (Vs.-St., XII, 1869, p. 197) 

 was studied the effect of varying proportions of albuminoids, fats, and 

 carbohydrates on the proportion of albumen (caseine) and fat in the 

 milk produced. 



Two cows received as a normal fodder during one experiment a mod- 

 erate ration of meadow-hay, to wit, 20 pounds per head, containing 

 about 1.5 pounds albuminoids, 8 pounds carbo-hydrates, and 0.5 pound 

 fiitty matter. To this was added, in experiment 2, 0.7-0.8 pound of 

 albuminoids, in the form of rape-cake, for the one cow, and beau-meal for 

 the other; in experiment 3, 2.3 pounds of starch; in experiment 4, 1 

 pound rape-seed oil ; while in experiment 5 the 20 pounds of hay were 

 fed alone. These experiments were performed in successive periods. 

 In order to make up for the natural depression in amount and change in 

 composition in the milk, with advance of time from calving, the above 

 order was followed with one cow and the same inverted with the other. 



Here follows a tabular statement of the average result. In order to 

 compare the composition of the dry substance in different experiments, 

 the composition shown by analysis is reckoned on a uniform percentage 

 of 12 per cent, of dry substance. 



Kind of food. 



Daily aTDonnt of milk produced pounds 



Containing dry substance per cent 



Eqiuvalent to milk of 13.25 per cent, dry sub.^tance 



Dry substance on basis of 1 2 per cent, m milk contained — 



Tat per cent 



Albuminoids do... 



16.15 

 13. 25 

 16.15 



4.18 

 2.74 



15. no 



13. 18 

 14.80 



3.95 

 2.92 



14.68 

 13.33 

 14.58 



3.88 



2.83 



15.47 



12.88 

 14.34 



3.85 

 2.80 



13. 02 

 13.24 

 13. 02 



3.99 



2.86 



It appears from the above figures that the variation in the proportions 

 of albuminoids, carbohydrates, and fats of the food had as good as no 

 effect on the relative amounts of these in the milk. 



* Vs.-St. Die landwirthschaftlichen Versuchs-Stationen. Organ of the German 

 Experiment- Stations. Dr. F. Nobbe, editor. Published at Chemnitz, Saxony. 



