29 



between ruminants, like the cow, sheep, etc., and nonruminants, like 

 the horse, although differences had been pointed out by a number of 

 observers. Averaging- the results of a considerable number of tests, 

 it appears that ruminants digest 26.9 per cent more protein, 5.4 per 

 cent more fat, 16.7 per cent more nitrogen-free extract, and 4 per 

 cent more crude fiber from timothy hay than horses. In the case of 

 oats, the amounts of protein digested were practically the same, but 

 the ruminants surpassed the horses by 12.8 per cent for the fat and 

 0.5 per cent each for the nitrogen-free extract and crude fiber. Sim- 

 ilar results were obtained with other coarse fodders and concentrated 

 feeds. Considering all the available experiments bearing on this sub- 

 ject, it seems fair to conclude that in general ruminants digest a larger 

 percentage of fat, carbohydrates, and crude fiber than horses, the 

 differences being most marked in the case of the crude fiber. These 

 results are in accord with what might be expected from differences in 

 the digestive organs of the different classes of animals. It is well 

 known that fineness of division is an important factor in considering 

 the thoroughness of digestion. The length of time any given food 

 material remains in the digestive tract is also important. The rumi- 

 nants have an opportunity to chew their food more thoroughly than 

 horses and retain it longer in the digestive tract. It is said that on 

 an average horses retain their food 4 days or less; cattle 3 or 4 to 7 

 or 8 days; sheep or goats from 3 or 4 days with ordinary rations to 7 

 or 8 da3^s when straw is eaten. That the food is actually more finely 

 divided b}' ruminants in chewing and digesting is indicated by the 

 mechanical condition of the manure, that from horses containing an 

 abundance of fairly large fragments of hay and other coarse fodders, 

 etc., while the manure of cattle commonly contains undigested residue 

 in a finer state of division. In the case of sheep the manure contains 

 the undigested residue in still smaller fragments. It is perhaps gener- 

 ally believed that crude fiber is chiefly digested by the action of bac- 

 teria in the intestine, and it is obvious that the longer materials remain 

 in the intestine the greater the opportunity for the action of such 

 micro-organisms. 



The fact that, other things being equal, horses digest their feed less 

 thoroughly than cattle, i. e., retain less nutritive material from any 

 given ration when it passes through the digestive tract, has been long 

 recognized. For this reason horsernanure is richer than manure from 

 cattle on the same ration. In other words, the horse manure contains 

 a larger proportion of the ration than cow manure, and hence, more 

 of the nitrogen and mineral matter, especially phosphoric acid and 

 potash, originally present in the feed. 



The value of the manure produced by horses was studied by the 

 Pennsylvania Station. Observations made with a number of horses 

 indicate that a horse produces annually about 12,700 pounds of fresh 



170 



