servation made in a companion experiment, reported in Dairy Husbandry 

 Research Mimeograph Xo. 3 (May, 1953). that cows fed a fine mixture 

 made greater gains in liody weight on the same amount of feed. 



N. F. CoLOVos, H. A. Keener, 

 H. A. Davis, K, S. Morrow 



Too Much Limestone Lowers Digestibility of Silage 



The results of the investigation reported last year showed that the 

 addition of 100 grams of limestone daily to the silage ration of yearling 

 dairy heifers lowered the digestibility of the protein by 6 to 8 percent. 

 This posed the very important question of the possible harm which the 

 inclusion of limestone in the ration in improper proportions may have. To 

 obtain more quantitative information on this problem, 9 complete nutri- 

 tive balance experiments were conducted this past year using 3 dairy 

 heifers with each animal being on a 0, 50-gram, and 100-gram pulverized 

 limestone daily intake along with grass silage- 



The investigation shows that the addition of 100 grams of limestone 

 caused a significant depression in the digestibility of the protein and the 

 energy thus confirming the results of the previous year. There was no 

 significant effect in the case of the 50-gram limestone intake. This indi- 

 cates that amounts normally contained in commercial grain mixtures should 

 have little effect on the digestibility of protein. 



N. F. CoLovos, H. A. Keener, 

 A, E. Teeri, H. a. Davis 



Effect of Sulfur Dioxide-Silage on 

 Vitamin Synthesis by Ruminants 



Insofar as nicotinic acid, riboflavin, and thiamine are concerned in 

 ruminant nutrition, sulfur dioxide appears to be a highly satisfactory sil- 

 age preservative. Although sulfur dioxide destroys much of the thiamine 

 in the silage, it counteracts the deficiency by producing conditions in the 

 rumen favorable to the synthesis of this vitamin. 



The alkalinity resulting from the feeding of limestone is unfavorable 

 to the intestinal or rumen synthesis of thiamine. 



A. E. Teeri, D. Josselyn, 

 N. F. CoLovos, H. A. Keener 



Mow-cured Hay Excells Silage and Field-cured Hay 

 in Digestibilty of Protein and Energy 



The effect of method of storage on the nutritive value of forages has 

 l)een studied for 3 consecutive years in 20 complete protein and energy 

 l)alance experiments with dairy heifers. It was found that mow-cured hay 

 excells both the silage and field cured hay in digestibility. During these 

 three years, however, feeding experiments have shown consistently greater 

 gains by heifers fed grass silage. These experiments indicate that while 

 the nutrients of silage are not as digestible as those of hay, they are utilized 

 to a considerably greater extent. 



N. F. CoLovos, H. A. Keener, 

 A, E, Teeri, H. A. Davis 



17 



