Miscellaneous Feeding Stuffs. 



201 



most cases there are other more refined and productive agricultural 

 plants which will serve the cattlemen of the plains better than cacti, 

 if plants which require protection and cultivation are to be grown. 



V. Cow's Milk and its By-products. 



From its nature and purpose it is reasonable to hold that normal 

 milk contains all the nutrients necessary to sustain the life of young 

 animals and that these are arranged in proper proportion. For this 

 reason milk is of peculiar interest to the student of animal nutrition. 

 The solids of milk are 98 per ct. digestible, exceeding all other com- 

 mon feeding stuffs in digestibility. 



297. Colostrum.— The first milk yielded by the mother for her 

 young, called colostrum, is thick and viscous and differs from ordi- 

 nary milk in being rich in protein and ash, that of the cow being 

 low in fat and milk sugar. The following table shows the average 

 composition of colostrum and normal milk of various farm animals:* 



The high protein content of colostrum is largely due to its excess 

 of albumen, which causes such milk to clot on heating. Colostrum 

 is laxative and highly important for cleansing the alimentary tract 

 of accumulated fecal matter and properly starting the work of diges- 

 tion. During the week following birth the yield of milk usually in- 

 creases and its composition gradually changes to the normal. 



298. Milk sugar.— Cow's milk contains from 4 to 5 per ct. of milk 

 sugar or lactose. Commercial milk sugar is a white powder of low 

 sweetening power and is much less soluble than cane sugar, which it 

 resembles in chemical composition. It has about the same feeding 

 value as the same weight of starch. When milk sours, some of the 

 sugar is changed to lactic acid, which curdles the casein. When 

 ' Konig, Chem. Nahruncrs-uncl Genussniittel, Vol. T, 1903. 



