Rumen Microorganisms. 



Studies were undertaken to obtain some information on the micro- 

 organisms present in the rumen of cattle. These organisms are responsible 

 for the digestion of a large proportion of the ruminant's feed prior to its 

 utilization by the animal. Particular attention was given to an investigation 

 of the bacteria which are actively engaged in the digestion of the cellulose of 

 the ruminant feed. Certain organisms were isolated from ruminal contents 

 and a study of the nature of these forms and the products of their cellulose 

 degradation was carried out. These products arising as a result of the 

 bacterial digestion of cellulose are used by the ruminant in its nutrition. The 

 bacterial forms isolated were a spore-forming rod and a yellow spherical 

 organism called a coccus. Both live only in the complete absence of oxygen. 

 Both seem to require some growth factor or factors (vitamins) present in 

 rumen fluid as it is necessary to add this as a supplement to the cellulose 

 mineral salts medium in order to obtain adequate growth. The products 

 formed from the digestion of cellulose are chiefly fatty acids; however, the 

 exact nature of these compounds is not known. Investigations are being car- 

 ried out at the present time on this phase of the problem. 



E. Katz 



Dairy Heifers Make Greater Gain on Grass Silage. 



Studies carried out during the past few years showed that grass silage 

 when fed to 12 to 18 months old dairy heifers as the sole ration produced 

 greater gains in body weight than either mow-cured or field-cured hay made 

 from the same field. Similar experiments this year gave comparable results, 

 although gains on all roughages were not as large as those of previous years. 

 In the experiment this year the heifers fed grass silage made gains that were 

 about twice as large as those made by the heifers fed mow-cured and field- 

 cured hays. There was no difference in the gains made on the two hays. 



The results of this experiment support the conclusion that was reported 

 previously that grass silage contains some sort of growth-promoting factor 

 in greater quantities than does mow-cured or field-cured hay made from 

 the same field. These results also indicate that grass silage can be used more 

 extensively in feeding dairy heifers in order to get normal gains in weight 

 with smaller expenditures for grain. 



H. A. Keener, N. F. Colovos 

 H. A. Davis, K. S. Morrow 



How Does the Cow Use Sulfur from Sulfur Dioxide Silage? 



Although sulfur dioxide has been found to be a very good silage pre- 

 servative, the desirability of feeding relatively large amounts of sulfur from 

 this source to the dairy cow has been questioned. Some people feel that the 

 continued feeding of S0 2 silage may have harmful effects on the cow which 

 would show up only after a considerable period of time. On the other hand, 

 others believe that such quantities of sulphur would not be harmful and 

 might even be of value nutritionally. 



The first step in studying this problem was to determine what the cow 

 does with the sulfur obtained from SOo silage. This was done by using a 

 legume silage preserved with radioactive sulphur dioxide. This silage was 

 preserved in steel drums and it was of excellent quality. After a period of 

 five months it was fed to milking dairy cows and the metabolism of the 

 radioactive sulfur followed. 



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