Agricultural Research in N. H. 29 



Of all the samples analyzed, 38 had a low solids-not-fat content, and 

 these either had a refractometer reading that indicated added water or the 

 readings were in the low range. 



This study has shown that it is possible to obtain low refractometer 

 readings on unadulterated milk samples having a low composition solids-not- 

 fat. 



H. C. Moore, H. A. Keener, A. E. Teeri 



Cobalt Treatment of a Nutritional Disease 

 of New Hampshire Cattle, Sheep, and Goats 



When a low cobalt New Hampshire hay was fed in a paired sheep ex- 

 periment, those animals which received the equivalent of 2 mg. of cobalt per 

 day gained approximately 21/2 times as much as the animals which received 

 no cobalt. Cobalt tolerance studies with growing dairy cattle have also been 

 completed. This work indicates that such animals may be fed cobalt up to 

 levels of nearly 50 mg. per 100 pounds of body weight per day for periods of 

 many weeks before harmful effects are produced. An experiment is now be- 

 ing carried out with sheep in an attempt to learn more concerning the func- 

 tions of cobalt in the diet. 



Chemical studies on forage samples taken from various parts of New 

 Hampshire substantiate the previous observation of widespread cobalt de- 

 ficiency in cattle, sheep, and goats throughout most of the state. 



An experiment to determine the effect of various fertilizer and cobalt 

 treatments of the soil on the cobalt content of the forage was started this year. 



This project is being carried out in co-operation with the U. S. Plant 

 Soil and Nutrition Laboratory, Ithaca, N. Y. 



H. A. Keener, G. P. Percival, K. S. Morrow 



Supplemental Vitamin D for Dairy Cows 



This experiment is being conducted in order to determine whether or 

 not lactating dairy cows under farm conditions in this area are benefited by 

 the feeding of supplemental vitamin D. 



A herd of 40 cows is being used. The cows are divided into three groups, 

 each member of one getting 15,000 I. U. of supplemental vitamin D per day 

 from irradiated yeast: those of another 50,000 I. U. of supplemental vitamin 

 D per day from the same source; while the members of the third group are 

 kept as controls. Results are based on chemical studies of the blood, vitamin 

 D assays on the blood and on the various roughages, and on the production 

 and general well-being of the cows. The experiment has not progressed far 

 enough to warrant any conclusions. 



This project is being partially supported by the Wirthmore Research 

 Grant and by the Standard Brands Research Grant. 



H. A. Keener, K. S. Morrow 



The Relation of Trace Minerals to Vitamin 

 Synthesis in the Rumen of Dairy Animals 



Two experiments are under way in order to determine a satisfactory 

 method for assessing the relation of trace minerals to vitamin synthesis in 



