282 THE CHEMISTRY OF CATTLE FEEDING 



unfit for use. It is said that when large quantities of brewer's 

 grains are fed to cows, the animals do not readily come in 

 season again, and so cannot be got " in calf." Apart from 

 this, there is no question that brewer's grains are a very 

 suitable food for milk cows. The large proportion of nitro- 

 genous matter they contain is favourable for milk production. 



Slump. Distillery grains when made from malt are very 

 similar to the product obtained from breweries. In some 

 cases, however, the practice is very different. Other things 

 besides malt, e.g. rice, maize, rye, potatoes, molasses, etc., are 

 introduced into the mash, yeast is then added, and the whole 

 is afterwards distilled directly, i.e. without first drawing off the 

 liquid. The residue which remains in the retorts, therefore, 

 contains everything except the carbohydrate that has been 

 converted into alcohol. It is known as distillery waste or 

 slump. It varies greatly in composition and character accord- 

 ing to the nature of the materials and the treatment. When 

 it includes potatoes, or molasses, it is scarcely fit for use as 

 food. The yeast is of course rendered inactive by the dis- 

 tillation, and its presence increases the percentage of digestible 

 nitrogenous matter in the product. Dried slump can also be 

 obtained. 



Gluten. This is a by-product obtained in the manufacture 

 of starch. Wheat, rice, maize, and potatoes are all treated in 

 different ways, and the by-products vary in composition and 

 character. 



In the case of wheat, the flour is first mixed to a thin 

 dough and then worked with water on fine sieves until 

 practically all the starch is washed out. The residue which 

 remains on the sieves consists of nearly pure wheat gluten. 

 It is dried and sold in a flaky condition. 



" Rice gluten " is dissolved by soaking with dilute alkalis, 

 and is reprecipitated with acids. The husks, from which the 

 starch is washed out with water, are also sometimes sold as 

 feeding stuff under the name of " rice sludge." 



In the case of maize, the grain is ground to flour in a 

 current of water. The husks or skins rise to the surface and 

 the germs sink to the bottom. The starch and gluten, which 



