ANNUAL REPORT, 1943-44 15 



3. Ground wheat (at three different rates: 100, 150, and 200 pounds per ton 

 of green crop). 



The urea when used alone proved unsatisfactorj-. The odor of the silage was 

 very objectionable and an undesirable type of fermentation had taken place as 

 indicated by the high pH (5.6), excessive amounts of butyric acid and volatile 

 bases, and complete absence of lactic acid. The one point in favor of the urea was 

 that apparently it preserved the carotene very well. The word "apparently" is 

 used advisedly, for although this result confirms work done elsewhere there is 

 some question in our minds as to its validity. It is feared that the urea, or per- 

 haps more correctly the type of fermentation induced by the high pH developed 

 when urea was added, may have altered certain non-carotene pigments sufficiently 

 to permit their estimation as carotene. 



When a combination of urea and molasses was used a somewhat better product 

 resulted. The pH was considerably lower, the volatile bases and butyric acid 

 were much lower, and considerable lactic acid was formed. 



The principal idea in using the urea was to increase the nitrogen content, and 

 hence the potential protein level, of the silage. The molasses was added not 

 only to act as a preservative but to furnish readily available energy for those types 

 of microflora which might synthesize the urea into protein, or at least into inter- 

 mediate nitrogenous compounds. That the idea did not work well in practice 

 is evidenced not only by the unsatisfactory quality of the silage as already noted, 

 but also by rather definite evidence that much of the urea was lost by leaching. 

 The, average nigrogen content of the leachings from the experimental silo for 

 four years previous!}' was 0.30 percent; when the urea was used it was nearly 

 double that amount (0.56 percent). 



Excellent silage resulted when 150 pounds or more of ground wheat was used. 

 The pH was satisfactory (4.3), volatile bases were low, butyric acid was either 

 low or absent, and there was a relatively high content of lactic acid. The silage 

 had a mild, pleasing odor and was very palatable to the cows. The herdsman 

 observed that it was the best quality silage he had fed in the eight years of ex- 

 perience with grass silage. 



The biochemical studies mentioned last year have been continued. The out- 

 standing conclusion from this phase of the work is that the kind of crop and the 

 stage of maturity at which it is harvested are of more importance in determining 

 the quality of silage than the preservative used. Preservatives are of some bene- 

 fit under certain conditions; ,but wherever it is practicable to control moisture 

 content by wilting the crop before storage, an excellent grade of silage can be 

 made without the use of a preservative. The one disadvantage of wilting (or of 

 letting the crop become more mature before cutting, which is another way of 

 reducing moisture) is that the carotene losses are somewhat higher than where 

 preservatives have been used. 



The Effect of Feeding Synthetic Thyroprotein to Milking Cows. (J. G. Archi- 

 bald.) This project, initiated in April, 1944, is being conducted in cooperation 

 with Cerophyll Laboratories Inc. of Kansas Cit}^ and in collaboration with the 

 State Department of Mental Health. Eighteen milking cows in the Holstein 

 herd at the Medfield State Hospital are being used for the work. The objective 

 is to ascertain the effects of feeding this synthetic hormone to milking cows for 

 relatively long periods of time. It is already known that the feeding of it causes 

 a definite positive response in milk secretion; the question which at once arises 

 and which it is the aim of this project to help answer is: Is this positive stimulus 

 lasting and how does it affect the cows in those respects other than milk produc- 

 tion? 



