Sources of Purchased Protein 315 



ing commercial protein feeds for dairy cows. Those 

 from which it is possible to choose are the oil meals, 

 the gluten meals and feeds, brewers' grains, malt 

 sprouts, peas and buckwheat middlings. The offals 

 from the milling of wheat, while somewhat more nitrog- 

 enous than the cereal grains, cannot be considered as 

 an abundant source of protein, although they are ex- 

 cellent components of a milk ration. 



Notwithstanding the claims which trade interests 

 may make to the contrary, no one of the above-men- 

 tioned feeding stuffs is alone essential to the economi- 

 cal production of the best of milk. There is no single 

 food or any one combination of foods that is always 

 best for dairy cows. Apart from certain considerations 

 which will be discussed later, a selection of the source 

 of commercial protein is a matter of availability and 

 of relative market cost. For instance, when gluten 

 meal costs $20 per ton few buyers can afford to pay 

 $27 for linseed meal to feed in any considerable quan- 

 tity. If prices were reversed, oil meal should be se- 

 lected. Both oil meals and gluten products may be 

 ignored if ground peas, buckwheat middlings or the 

 brewers' residues are available at more favorable prices. 

 It is simply necessary that the grain ration shall con- 

 tain protein in sufficient quantity and proportion, and 

 shall be made up of a variety of materials, better not 

 less than three kinds, all of .which should be palatable 

 and exert no deleterious influence upon the milk or its 

 products. There are few grain products that cannot 

 be used successfully in grain mixtures, even though 

 they are undesirable when fed alone. 



