16 BULLETIN 728, U. S. DEPARTMENT OF AGRICULTURE. 



The analyses of soap weed and sotol show that the food value of the 

 different parts of the plant varies and that the food content of the 

 same parts of different plants also varies. This is as was to be 

 expected. The growing parts of the plant would naturally have less 

 fiber and more protein because they are growing, and the leaf bases 

 and young stems would also show relatively higher food content 

 because of their use by the plant for storage of such material against 

 the flowering time. A change in the percentage of one constituent 

 of necessity affects the figures for all the rest. 



The average values for the 13 analyses of soap weed and 6 analyses 

 of sotol are more nearly like those of western prairie hay (average of 

 42 analyses) than any other kind of feed usually fed, though they also 

 approximate those of corn stover. 



There was considerable discussion among those interested about 

 the relative values of this feed and alfalfa hay. Assuming that they 

 are equally digestible and that there is nothing deleterious in the 

 soap weed, the figures given in Table I show something of the relative- 

 merits of the two feeds. From these figures alone we see that for 

 perfectly dry material the amount of protein in 100 pounds of alfalfa 

 is about twice as much as that in the soap weed and that the fat- 

 carbohydrate percentages are higher in the soap weed. Both these 

 conditions indicate higher feed value in the alfalfa. In addition to 

 these is the condition in which the material is fed. Alfalfa is fed when 

 air dry, and 100 pounds of hay furnishes about 93 pounds of dry 

 matter of which between 8 and 9 pounds is crude protein. Soap weed 

 is fed fresh cut and 100 pounds of the feed contains only about 35 

 pounds of dry matter, of which about 2\ pounds is protein. Thus, for 

 every 100 pounds of alfalfa fed, an animal gets nearly three times as 

 much feed which' is at the same time twice as good feed as when he is 

 fed 100 pounds of chopped yucca. This should answer the question 

 very emphatically in favor of alfalfa, but at the same time it should 

 in no way detract from the value of the soap weed as an emergency 

 feed. 



It must be clearly recognized that the soap weed and all such feeds 

 are of low feed value and, taken alone, are feeds of very wide nutritive 

 ratios. In other words, the amount of tissue-building food material 

 (protein) found in these feeds constitutes only a small proportion of 

 the total amount of the material fed, and is also small in amount when 

 compared with the other food materials (fats and carbohydrates) 

 present in such feeds. The fresh, moist condition of the feed when 

 fed is advantageous, and under certain conditions it would no doubt 

 be worth while to feed a certain amount of such material to stock 

 on dry feed. However, under most conditions the expense of pre- 

 paring the feed is such that it is not warranted unless no other feed 

 is available at a less cost. 



