vitamin D when mowed, and it contained appreciable amounts of vitamin D 

 after irradiation. Relatively high levels of vitamin D were found in forages 

 cut at a mature state, and these values were increased markedly after irradi- 

 ation. 



The results of this study indicate that first-cutting forage harvested at 

 the generally recommended stage of maturity cannot be counted on as a 

 good source of vitamin D even if it is field cured. Because second-cutting 

 hay generally contains considerable vitamin D after field curing, the prac- 

 tice of ensiling first-cutting forage and making the second cutting into hay 

 appears to be a desirable one. This is true not only from the standpoint of 

 the vitamin D intake of the cow, but also in conserving other nutrients. 



H. A. Keener 



Sulphur Dioxide Excells Molasses as a Silage Preservative. 



There has been considerable interest among dairymen in the use of 

 sulphur dioxide as a silage preservative during the last few years. While 

 there were many favorable reports on this material as a silage preservative, 

 there appears to be no experimental work reported where this was shown by 

 means of nutrient balance experiment with dairy animals. In order to de- 

 termine the value of sulphur dioxide as a silage preservative and to compare 

 it with cane molasses, a study of the relative digestibility and utilization of 

 energy and protein of silages preserved with these materials was conducted. 



Then complete energy-and-protein-balance experiments with six dairy 

 heifers fed timothy silage and oat silage preserved with sulphur dioxide and 

 with molasses show that the digestibility and utilization of these feed ingredi- 

 ents was higher in the sulphur dioxide-preserved silages. Both the oat and 

 the timothy sulphur dioxide silages had much better color and keeping quali- 

 ties than the comparable silages preserved with molasses. The palatability of 

 the sulphur dioxide silages were equally as good as the molasses-preserved 

 silages. 



N. F. Colovos, H. A. Keener 

 H. A. Davis, A. E. Teeri 



Digestibility and Utilization of Protein in Mow-Cured Hay 

 Superior to That of Field-Cured Hay. 



It generally is recognized that in New England the key to profitable 

 dairying is the maximum use of high quality home-grown roughage. To 

 achieve this objective to the greatest possible extent, it is necessary that the 

 best possible method of harvesting and storing home-grown roughages for 

 winter feeding be used. One of the concerns of this Station for the past 

 three years has been the study of the relative digestibility and utilization of 

 the protein and energy of mow-cured and field-cured hays. In twenty-two 

 complete protein and energy balance experiments with dairy heifers over 

 this period, it was found that the mow-cured hay excelled the field-cured hay 

 in protein digestibility and utilization. The relative digestibility and utiliza- 

 tion of the energy, however, was not significantly different in the two types 

 of hay. 



N. F. Colovos, H. A. Keener 

 H. A. Davis, A. E. Teeri 

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