52 Bulletin 173. 



three eacli, during four periods of 21 to 26 dcays each, with a seven- 

 day preliminary period. They conclude : 



" That the same amount of digestible matter in the narrow rations 

 produced from 11.8 to 12.9 per cent more milk than did a like 

 amount of digestible matter in the wide rations, and that neither 

 the narrow nor wide rations produced any decided change in the 

 composition of the milk. 



Jordan and Jentner* changed the ration of a cow in three ways : 

 "(1) By decreasing the fat in the food from about the usual quan- 

 tity to practically none ; (2) by producing wide variations in the 

 protein supply and nutritive ratio, and (3) by producing wide varia- 

 tions in the supply of total digestible material." The cow was " fed 

 during ninety -live days on a ration from which the fats had been 

 nearly all extracted, and she continued to secrete milk similar to 

 that produced when fed on the same kinds of hay and grain in their 

 normal condition." The food-fat eaten during this time was 11.6 

 pounds, 5.7 pounds of which was digested, while the yield of milk- 

 fat was 62.9 pounds. Throughout the whole experiment, " the com- 

 position of the milk bore no definite relation to the amount and kind 

 of food." 



Wingf added ordinary beef tallow to the usual grain ration of 

 ten cows, giving them at first four ounces per head, and increasing 

 the amount gradually until each cow was consuming two pounds 

 daily, which amount was fed for six or seven weeks. He found 

 " no increase in the per cent of fat in the milk as a result of feed- 

 ing tallow in addition to a liberal grain ration." 



Waters and Hess:}: gave rations varying in nutritive ratio from 

 1:3.9 to 1:6.65 to nine cows through four periods of thirty days 

 each, and say : "It appears that the narrower nutritive ratio tended 

 to increase the per cent of fat." 



Farrington§ studied the effect of heavy grain feeding by giving 

 three cows from December 1 to Juno 1, in eight periods ranging, 

 from 6 to 51 days, an amount of grain increasing continually from 



*New York (State) Station, P.ullctin 133, 1897. 

 tNew York (Cornell) Station. Hulletin. 92, 1895. 

 :}: Pennsylvania Station, Annual Report, 1895, p. 56. 

 ^Illinois Station. Hullctin '21, ISill. 



