tion, it can be purchased most economically in the high-grade protein 

 concentrates, such as cottonseed meal, gluten feed, distillers' dried 

 grains and the like. 



4. Nutritive Ratio of Cattle Feeds. 



The numerical relation which the digestible protein bears to the other 

 digestible organic nutrients (fibjr extract matter and fat ') is termed 

 the nutritive ratio of the feed or ration. Timothy hay has. for exam- 

 ple, 3 parts of digestible protein to 47.3 parts of other digestible nutri- 

 ents, or as 1 is to 15.8. This is termed a very wide nutritive ratio. Gluten 

 feed contains 22.3 parts of digestible protein to 58.6 parts of other 

 digestible nutrients or as 1 is to 2.6. This may be termed a very narrow 

 nutritive ratio or proportion. All feeds having a nutritive ratio of 1 to 

 5 or less may be said to have narrow ratios, those from 1 to 5 to 1 to 8 

 a medium ratio, and above 1 to 8 a wide ratio. 



The cereals and other non-leguminous coarse fodders have medium 

 to wide ratios, leguminous coarse fodders medium ratios, and the 

 leguminous seeds and most concentrated by-products narrow ratios. 



5. Combining Coarse and Concentrated Feeds (Balanced 



Rations). 



Desirable rations for dairy stock should possess (a) palatability, (6) 

 sufficient bulk, and (c) 1 part of protein to 5.5 to 7 parts of the other 

 digestible organic nutrients. If the ratio is much narrower than 1 to 

 5.5, the ration is likely to be too stimulating for continuous feeding, and 

 the animal is likely to become thin in flesh. If the ratio is much wider 

 than 1 to 7, the tendency will be for the animal to put on fat rather 

 than to give milk. In both cases the ration may be said to be out of 

 balance. 



For both economical and physiological reasons it is necessary that a 

 considerable portion of the daily ration of the dairy animal should be 

 composed of coarse fodder or roughage, because such materials are eas- 

 ily and cheaply produced upon the farm, and because the digestive 

 tract of the bovine is especially suited to utilize them. Most of these 

 home-grown coarse feeds, however, are very high in carbohydrates, low 

 in protein, and have a relatively low digestibility. It is necessary, 

 therefore, to supplement them to an extent with the cereal grains, 

 which, though relatively low in protein, are very digestible; and with 

 the concentrated by-products, which in addition to a relatively high 

 digestibility, are quite rich in protein. A single illustration will make 

 this clear. Many experiments have demonstrated that a 1,000-pound 



' The fat is converted into the energy equivalent of the starch or fiber by multiplying by 2.2; 

 thus, 3 per cent of fat would have an energy equivalent of 6.6 per cent or parts of starch. 



