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MASS. EXPERIMENT STATION BULLETIN 230 



the institute, as a result of his own experiments and tliose conducted in 

 Europe, deduced a formula for determining net energy, based upon chemical 

 analysis, total energy and metabolizable energy. In the experiments here 

 reported, we have made use of this formula after having determined the- 

 composition and the total and metabolizable energy in each feedstuff, as well 

 as its digestibility; and it is these two units of measurement — 7iet energy, 

 expressed in therms', with digestibility as an aid — that we have used in 

 getting at the relative values of the feeds studied. 



METliOlJ OK Fl;OLE))(II:K 



Two horses were used in each trial. Eacii feed was analyzed and its total 

 energy determined. Definite amounts daily were fed, the feces and urine 

 collected, and the energy contamed in theni determined and subtracted from 

 the total energy of the feed, wlucii gives the metabolizable energy. By the 

 application of the formula mentioned above, the net energ)^ was estimated. 

 In the above procedure we were able also to determine digestibility. Each 

 actual experiment required about three weeks for its completion, in addition 

 to a large amount of work in the chemical laboratory and in the calculation 

 of the results. 



Some Results of the Experibient 



The Story of Alfalfa. 



Two different lots of alfalfa were tested, one grown in New York state 

 and the other on the Experiment Station grounds. The New York sample 

 contained 11.7 per cent protein and 3.5.2 per cent fiber, while the Station 

 sample contained 17.7 per cent protein and 27.5 per cent fiber. It is evident 

 that the former sample was more mature than the latter. 



Average Digestion Coefficients and Net Energy Values 



These results indicate that the New York sample was more mature and less 

 utilized by the horses than the Massachusetts sample; while the net energy 

 values show that the horses had to expend considerably more energy to digest 

 the New York, or late-cut sample. 



The comparison of the digestibility of alfalfa by horses and cattle, given in 

 the table, shows that cattle are able to digest alfalfa to a greater degree than 

 are horses, although the protein is well and about equally digested by both 

 classes of animals. 



1 The therm represents the amount of heat required to raise 1000 kilograms of water 

 1 degree Centigrade, and is used as a unit of measurement for energy. 



