28 Experiment Station Bulletin 363 



is materially less for protein and higher for total digestible nutrients than 

 is indicated bv published estimates (F. B. Morrison, Feeds and Feeding, 

 20th Edition,' pp. 953 and 912, 1936). 



A comparison of the digestible nutirents of the grass and of the hay 

 cut about two weeks later shows a decrease of 1 3 per cent in digestibility 

 of the protein and of 17 per cent in digestibility of the dry matter in the 

 latter. 



Determinations of the carotene content of the grass indicated that it 

 remained constant at about 16 to 17 micrograms per gram of dry matter 

 during the period of cutting. The carotene content of the hay has not 

 been determined. 



As this appears to represent the first instance in which the digestible 

 nutrients of pure timothy at pasture stage has been experimentally de- 

 termined, the result is of particular interest because of the wide diver- 

 gence from published estimates. It also indicates the extraordinary ne- 

 glected state of research and almost entire lack of specific physiological 

 evidence on the nutritive value of one of our primary sources of food 

 for livestock. 



E. G. Ritzxian, N. F. Colovos* 



The Effect of Vitamin D on the Metabolism and 

 Utilization of Energy and Protein by Calves 



This study was carried out on six male calves. Two of them were 

 given an adequate amount of vitamin D (in form of irradiated yeast) and 

 four were deprived of this vitamin supplement. All calves Mere kept in 

 darkened stalls during the entire time of the experiment and, except for 

 the vitamin differential, all received the same feed ration. 



At the end of the vitamin-deficiency period, digestion balances and 

 metabolism measurements were carried out on each calf to determine 

 the degree to \\hich deficiency of vitamin D affects the utilization of 

 protein and energy in very young calves. Although the digestion bal- 

 ances and the metabolism measurements are completed, the extensive 

 chemical determinations involved are still under way. 



\^isual effects of vitamin D deficiency were, however, very striking 

 and of the usual rachitic type as regards effect on bone formation. The 

 calf most severely affected developed constant intensive bloating during 

 the final stage so that a trochar had to be used daily to release the gas. 

 Post-mortem inspection showed the rumen to be almost entirely filled 

 with semi-solid matter (i.e. moisture swollen beet pulp) M'hich it \\'as 

 apparently unable to remove. This was apparently an accumulation of 

 numerous days of feeding. Whether this Mas due to occlusion or to para- 

 lysis of the musculature of the rumen was not determined. However, 

 none of the controls were so affected. 



Although all calves were fed on the level of the lowest consumer 

 there was a difference of 10 per cent in metabolism (i.e. total heat pro- 

 duction) between the controls and deficients, the latter having the high- 



•Qn Military leave. 



