254 LIVESTOCK ON THE FARM 



METHOD OF CALCULATING A RATION 



Suppose that a bunch of pigs is two months old and weighs 

 685 pounds. The foregoing charts show that at this time the 

 pigs require daily for every 100 pounds of live weight 13 pounds 

 of water, 0.6 pound of digestible crude protein, and 2.4 pounds 

 of digestible carbohydrate. Multiplying these quantities re- 

 spectively by the total live weight, namely, 685 pounds, and 

 pointing off the proper figure, it is seen that the pigs will re- 

 quire a total of 89.05 pounds of water, 4.11 pounds of diges- 

 tible crude protein and 16.44 pounds of digestible carbohydrate 

 a day. Suppose that alfalfa, corn, barley, skim milk, soy 

 beans and water are to be used to make up this ration. With a 

 table like the following, specifying the amounts of digestible 

 nutrients present in these feeds from 1 to 9 pounds inclusive, 

 a ration may be accurately calculated. 



From this table tenths of pounds, units of pounds, and 

 tens of pounds may be added to the ration by reading the 

 quantities of nutrients correctly with respect to the decimal 

 point. To get tenths read with the decimal point one place 

 to the left and for tens of pounds one place to the right. The 

 use of the table eliminates multiplication at each operation. 



Pigs two months old can use but a limited quantity of a 

 roughage like alfalfa, consequently in making up this ration 

 not much can be used at this time. Relatively more should 

 be added as they get older. Suppose that corn and barley are 

 to be used in the proportion of two parts of corn to one part of 

 barley and that but a limited amount of skim milk is at hand. 

 In order to make up this ration, then, the following is evolved: 



The total amount of nutrients required for each day as 

 shown above for the bunch of pigs weighing 685 pounds is as 

 follows : 



Water Protein Carbohydrate 



89.05 4.11 16.44 



These are obtained by first putting down the desired amount 

 of each roughage (alfalfa), with its water, protein, and car- 

 bohydrate, then the carbohydrate concentrates, corn and 

 barley, and then the skim milk. Have enough of these so that 



