DIGESTION EXPERIMENTS WITH CATTLE FEEDS. 



61 



While the digestion results with peanut meal are not as high as the average 

 results secured by German observers, the utilization of the protein, nitrogen-free 

 extract and fat, of which it is largely composed, shows that the meal should be 

 placed among the best of the protein feedstuffs. 



The digestion results secured \\-ith the peanut skins are neither concordant nor 

 very satisfactory. However, in each case they show that the fat, which comprises 

 nearly 30 per cent of the skins, was quite fully utilized. When the skins were fed 

 with hay (period 8), the digestion of the fiber of the ration seemed to be noticeably 

 depressed or interfered with; and when fed with hay and gluten feed (period 12), 

 none of the organic ingredients except the fat was digested. One might therefore 

 conclude that the fat interfered with the utilization of the protein, fiber and nitro- 

 gen-free extract. On the basis of the above results, their value as a cattle feed is 

 questionable. In order to utilize them economically, it may be possible to extract 

 the oil and use the residue for litter or for packing purposes. 



Peanut shells are shown to have a low digestibility, inferior even to oat hulls. 

 While the small percentage of protein and fat which they contain seems to be well 

 utilized, the fiber which comprises over 60 per cent of the dry matter apparently 

 is little if any digested. The shells, therefore, are of little value as a feed. 



Velvet Bean Feed. 



Velvet bean feed consists of the ground seed and pod of the velvet bean, a rank- 

 growing tropical legume which is cultivated extensively in Florida, Alabama and 

 Mississippi. It has appeared at different times in Massachusetts, and a full report 

 on its merits may be found in Bulletin 197. 



Its composition on a dry matter basis is as follows: dry matter 88.16, ash 5.79, 

 protein 18.94, fiber 14.50, nitrogen-free extract 56.16, fat 4.62. It resembles wheat 

 bran in composition, but has slightly more protein and considerably more fiber, 

 due to the presence of the pods. The average of the four trials shows about the 

 same amount of digestible protein as is found in wheat bran. The fiber, nitrogen- 

 free extract and fat are, however, somewhat more digestible, and on the basis of 

 total digestible nutrients the velvet bean feed has about 11.5 per cent greater feed- 

 ing value than bran. 



Summary. 



In the table following, the average composition of each feeding stuff is given, 

 together with the average coefficients of digestibility and the limits of error, calcu- 

 lated by Bessel's formula. The error limit is large in some cases, the cause therefor 

 being explained in the discussion of results on pages 53-61. In case of oat hulls 

 and peanut shells the results vary so widely that the limits of error are not stated. 

 The coefficients indicate that much difficulty was experienced in digesting these 

 materials and that they possessed comparatively little nutritive value. The coef- 

 ficients for the ash in all cases are of uncertain value because it is now recognized 

 that a considerable portion of the digested mineral matter is excreted through the 

 feces, whereas in case of organic nutrients the end products of digestion are elimi- 

 nated through the lungs, skin and urine. Where the percentage of fat in the feed 

 is small — 1 per cent or less — the coefficients have little meaning. 



