A STUDY OF RATIONS FED TO MILCH COWS. 95 



DISCUSSION OF THE TESTS. 



Herd T. Tests Nos. ^g and 61. — This experiment was made 

 with a herd of thirteen cows, the animals being the same in 

 both tests. The cows were all grade Jerseys and were esti- 

 mated to weigh from 700 to 850 pounds. Most of the cows 

 had calved within six months prior to the first test, and none 

 were due to calve within three months of the close of the 

 second test. The herd was well stabled, the temperature being 

 quite uniform irrespective of the weather. The coarse fodder 

 used con.sisted of corn stover, finely cut, and oat hay of good 

 quality. 



The first test began December 1 1 and continued twelve days. 

 In this test the average daily ration was composed of about 10 

 pounds of oat haj^ and 8 pounds of corn stover, and about 8.5 

 pounds of mixed grains consisting of wheat bran, corn meal 

 and oat feed, with a very little cotton seed meal. The ration 

 was estimated to contain 1.75 pounds of digestible protein and 

 was quite a wide one, having a ratio of 1:7.6. 



There was an interval of sixteen days between the tests. 

 The second test began January 8 and continued twelve days. 

 The same kinds of coarse fodders were used in this test as in 

 the first, although the amount of oat hay was slightly reduced. 

 The grain feed of the basal ration consisted of 8.0 pounds daily 

 of a mixture of 150 pounds of Quaker dairy feed, 300 pounds 

 of wheat bran, 200 pounds of corn meal, 75 pounds of cotton 

 seed meal and 125 pounds of Chicago gluten meal, and fur- 

 nished about 2.0 pounds of digestible protein per day. The 

 protein mixture for the supplemental ration consisted of equal 

 parts by weight of cotton seed and Chicago gluten meals and 

 Quaker dairy feed. There were two groups of cows which 

 received the protein mixture in addition to the basal grain feed. 

 In one group (B) there were four cows which received one 

 pound each, and in another group (C) there were five cows 

 which received two pounds each of the protein mixture. There 

 was estimated to be .25 of a pound of digestible protein in each 

 pound of the mixture, and the amount of protein fed was in- 

 creased one pound for every .15 of a pound of butter fat pro- 

 duced above .65 of a pound. There were two cows, however, 

 whose yields of butter fat in the first test indicated that they 

 should have received three pounds of the protein mixture if 



