568 SUCCESSFUL FARMING 



The Requirements of Farm Animals. — Knowing the digestible nutri- 

 ents and the energy in the different feeding-stuffs and the amounts of 

 nutrients and energy required by farm animals, one can formulate 

 approximately a proper ration for different farm animals under different 

 conditions. 



The Balanced Ration. — A balanced ration is a ration which contains 

 all the nutrients in such proportions, forms and amounts as will nourish 

 properly and without excess of any nutrient, a given animal for one day. 

 Extended study of the amount of each nutrient required by the different 

 farm animals for the various purposes for which they are kept has led to 

 the formation of so-called "feeding standards." Theoretically, feeding 

 standards may be looked upon as formulas which tell at a glance the amount 

 of each nutrient necessary to produce a given result. In practice, however, 

 feeding standards cannot be regarded as such, but only as a guide to be 

 used in connection with one's practical knowledge of the amounts, propor- 

 tions and combination of feeds which are used in stock feeding. Although 

 there are a number of valuable feeding standards, the limits of this chapter 

 will permit a discussion of only a few. 



The Wolff-Lehmann Standards show the requirements of farm animals 

 under different conditions, expressed in pounds of total dry substance, 

 digestible crude protein, digestible carbohydrates and digestible fat per 

 1000 pounds live weie-ht. The nutritive ratio required by the animal also 

 is given. 



The calculation of a ration according to any feeding standard consists 

 essentially of three steps: (1) Having given the requirements for an 

 animal of a given weight, usually 1000 pounds, the requirements of the 

 animal under consideration are determined. (2) A "trial ration" is 

 assumed, using the amounts and proportions of concentrates and rough- 

 ages which, in the opinion of the feeder, are necessary. (3) The trial 

 ration is modified by adding or deducting concentrates or roughages of 

 such composition as to furnish approximately the required amounts of 

 nutrients. 



Thus, for example, one calculates a ration according to the Wolff- 

 Lehmann standard for a 1200-pound horse at light work as follows: 

 According to the standard (see Appendix, Table III) the requirements 

 of a 1000-pound horse at light work are as follows: dry substance, 20 

 pounds; digestible protein, 1.5 pounds; digestible carbohydrates, 9.5 

 pounds; and digestible fat, 0.4 pounds. The first step is to calculate the 

 requirements of a 1200-pound horse, which are found to be as follows: 

 dry substance, 24 pounds; digestible protein, 1.8 pounds; digestible car- 

 bohydrates, 11.4 pounds; and digestible fat, 0.5 pound. The second step 

 is to assume a trial ration which will meet approximately the requirements 

 as determined in the first step. From the amount of dry substance required 

 and from practical experience, one judges that a ration consisting of 12 

 pounds of oats and 14 pounds of timothy hay will about answer the pur- 



