65 



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 (fiber, extract matter and 

 fat') is termed the nutritive ratio of the feed or ration. Timothy 

 hay has, for example, 3 parts of digestible protein to 47.3 parts 

 of other digestible nutrients, 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, and the 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) palata- 

 bility, {b) 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 easily and cheaply produced on the farm, and be- 

 cause 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 cow, produc- 

 ing daily 10 quarts of milk of average quality, needs approximate- 

 ly the following amounts of digestible nutrients: 



' 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 percent or parts of starch 



