11 Sept., 1916.] 



Food Values and Rations. 



515 



Comparison by the use of the starch equivalent, although unsatis- 

 factory, is perhaps the best system in use at present, provided compari- 

 sons are restricted to members of natural groups, as green fodder and 

 hays, grains, mill products, oil meals. The 30 net starch equivalents 

 contained in 100 lbs. of hay may be compared with 20 in oaten silage, 

 provided each is of good quality, and the deduction that 1 lb. oaten hay 

 equals 1^ lbs. silage is supported by practice. In fact, when a scarcity 

 of green feed prevails, the value of silage is greater, owing to its 

 succulence. To compare the starch equivalents of bran with those of 

 the oil meals or hay is incorrect, and would lead to wrong conclusions, 

 because the three substances named differ greatly in composition and 

 belong to separate groups. When the protein and carbohydrate are used 

 to perform similar functions, viz., heat production, the use of starch 

 equivalents may be made to all classes of foodstuffs. 



For this purpose protein is too expensive, and when used, as they 

 should be, in the performance of dissimilar functions, viz., protein for 

 development, repair of tissue and milk secretion, carbohydrate and fat 

 for production of heat and formation of fat, no comparison between the 

 nitrogenous and non-nitrogenous constituents is possible. For this reason 

 cattle foods are arranged in groups. 



Hays. — To provide the nutrients necessary for maintenance when 

 grasses or green fodder are insufficient for the total food supply, when 

 only a small quantity of milk is yielded. 



Grasses, Clovers, and Green Fodder. — To supply sufficient to meet all 

 needs. 



Concentrates. — To provide sufficient nutrients for milk supply when 

 a deficiency occurs in natural pasture. 



In practice no attention need be given to the analysis of ordinary 

 green crops or hays, insomuch as the analyses show that wide variations 

 are greatest amongst individual samples of the same variety. Season, 

 soil, climate, manure, farming practice, and stage of growth are all factors 

 which influence the value of green fodders and hay. The following may 

 be accepted as generalized statements :— Lucerne hay makes the best 

 roughage, then follow clover, mixed grass, and cereal hays, when grown 

 and harvested under favorable conditions. Green oats are preferred by 

 cows to green barley, and have also a higher Value for milk production. 

 Barley grows more vigorously in the early stages of growth than oats. 



Hays cut green are more nutritious than hays cut at a later period 

 Millet is superior to maize for milking cows. Maize yields a heavier 

 crop and makes excellent silage. 



Victorian Analysis of Concentrates. 

 (Showing percentages of nutrients available for milk production,) 



