II. R. WOOD.AIAN 1H3 



uniforniity iu the growth of the oat aud tare crop, show clearly that both 

 hay and silage contain somewhat more digestible protein and fibre and 

 rather less digestible nitrogen-free extractives than the green crop. The 

 amounts of digestible ether extract vary within wide limits, the hay 

 figure being very low and the silage figure relatively high. 



In commenting on the decrease of digestibihty which is assumed to 

 occur when a green crop is ensiled, Henry and Morrison^ write: "The 

 exceedingly favourable results from silage feeding are therefore due to 

 the palatability of tiie silage, its beneficial eft'ect on the liealtli of the 

 animals and the fact that less feed is wasted than when dry fodder is 

 used." The results of this investigation indicate, however, that a con- 

 tributory factor of great importance is the fact that the silage possesses 

 a digestibility and a nutritive value which are only slightly, if at all, 

 inferioi- to those possessed b}' the green forage from which it has been 

 produced. 



Comparison of Metabolisable Eneruy of Greex Oats and 

 Tares, Oat and Tare Hay and Oat and Tare Silage. 



In order to e.xtond the comparisons already outlined, it was decided 

 to make determinations of the metabolisable energy of the three types 

 of fodder. The metabolisable energy may be regarded as that portion of 

 the gross energy of a foodstuff which is available for utilisation in the 

 body of the animal; it does not, however, represent the true value of the 

 foodstuft' for general production purposes, since further deductions are 

 necessary in allowing for the energy used up in the processes of mastica- 

 tion aud digestion. The metabohsable energy is ascertained by deducting 

 from the gross energy of the food.stufi the losses of energy from the body 

 in the form of the hquid, sohd and gaseous excreta; its determination 

 involves, therefore, the carrying out of bomb calorimetric experiments 

 on the foodstuft', dry faeces and dry matter of the urine. The course of 

 the determinations will be gathered from a study of the following tables. 



Table XIX. Details of urine output during trials. 

 Sheep I Sheep II 



Period 



Green oats and tares 

 Oat and tare hay 

 <Jat and tare silage 



Feeds and Feeding, p. 51, 1917. 



