4s8 EVENING DISCOURSES 



The crude protein of a food is the percentage of nitrogen multiplied by 

 6-25. The percentage of crude protein in linseed cake is 29. 



The quantitative food requirements of farm animals have been studied 

 far more intensively and accurately than have those of human beings. 

 The amounts of starch equivalent and protein required by domesticated 

 animals at different periods of their life, and for different requirements, 

 have been determined practically, so that it is now a matter of routine to 

 provide them with a ' balance ration ' that contains all the necessary amounts 

 of carbohydrate, protein, etc., and in the correct proportions, not only for 

 ' maintenance,' i.e. for keeping the body supplied with energy, but also for 

 ' production,' i.e. for enabling it to produce the needed amounts of market- 

 able produce, milk, meat or eggs. 



As an illustration : a milch cow weighing 1,000 lb. requires daily 6 lb. 

 of starch equivalent, and 06 lb. of protein equivalent, to maintain it in 

 health and keep its weight constant. For each gallon of milk (3 -7 per cent, 

 fat) it produces, it will require 2-5 lb. starch equivalent, including o-6 lb. 

 digestible protein. Hence a cow weighing 1,000 lb. and giving 4 gallons 

 of milk a day will need : 



Starch Equiv. Protein Equiv. 

 lb. lb. 



For maintenance . . 6 • o o • 6 



For producing 4 gal. milk . . lo-o 2*4 



Total to be fed per day . i6-o 3-0 



These amounts can be made up in a variety of ways, the starch equivalent 

 can be supplied as grass, hay, straw, oats, barley, maize, roots, etc., and the 

 protein as oil-cake or good grass ; but it is essential to keep the ration 

 ' balanced ' in respect of S.E. and P.E. to avoid waste and to maintain 

 health ; and also to see that its bulk does not exceed the appetite of the 

 animal. 



Besides this, the animal must receive sufficient minerals and vitamins to 

 maintain health. 



Some Typical Food Requirements. 



Starch Equiv. Protein Equiv. 



To feed a milch cow for i year and pro- 

 duce 800 gall, milk .... 

 To feed a heifer calf from 2 months 



(150 lb.) to 3 years (11 cwts.) when it 



produces its first calf 

 To feed a calf until it is a 2-year-old 



bullock weighing 10 cwts. 

 To feed a young pig from 50 lb. to 160 lb. 



(bacon weight) .... 



To feed a young sheep (teg) from 80 to 



180 lb. . 

 To feed a hen for i year — produce 160 



eggs 



To feed a man for i year doing hard work 

 To feed a man for i year doing little 



work ...... 



To feed a boy of 10 years growing and 



energetic ..... 



