4/2 PRINCIPLES OF AGRICULTURAL CHEMISTRY 



periments to ascertain the effect of an increase in fat in the food 

 on the quantity of fat in the milk, have given contradictory results ; 

 but the weight of the evidence is to the effect that the percentage 

 of fat in the milk is not modified by the quantity of fat in the 

 food. 



Jt was observed in Holland that butter from cows on pasture 

 in the fall decreased in volatile acids. Sjollema found that beet 

 heads would prevent this, and later found cane sugar to have the 

 same effect. The pasturage was found to contain less carbohy- 

 drates in the fall. It is possible that a part of the volatile acids 

 in butter originate from the fermentation in the animal, and for 

 this reason, a smaller amount was present as the easily ferment- 

 able carbohydrates in the food decreased. The character of the 

 fat fed also has an effect upon the composition of the butter. 

 Various experiments in adding oils to rations have produced but- 

 ter that was somewhat affected by the character of the oil fed. 



Harrington 1 found that feeding cottonseed meal made the 

 butter much harder, and decreased the quantity of volatile acids 

 in it. For example, while normal butter contains approximately 

 7.0 per cent, fatty acids volatile with steam, butter made from 

 the milk of cows fed cottonseed contained in one case only 3.5 

 per cent, volatile acids. 



Standards for Milk Cows. The amount of feed to be fed must 

 depend upon the quantity of milk given as well as on the weight 

 of the cow. The feeds should be adjusted to the individual 

 animals, and not to the average of the herd. The adjustment 

 may easily be made by arranging the cows in groups according 

 to yield of milk, and adjusting the ration by measuring different 

 quantities of the concentrates for each group. The value of the 

 milk as related to the cost of the feed must determine whether the 

 milk production should be forced to a maximum by giving a 

 heavy ration, or whether a somewhat lower ration should be fed 

 for more economical production. As stated before, the produc- 

 tion of the largest possible amount of milk requires much more 

 food than the production of a somewhat smaller amount, as the 

 effect of each addition of food on production diminishes as the 

 1 Texas Bulletin, u. 



