Rural School Leaflet 1153 



repair any loss of material in the make-up of the body itself; (3) to store as 

 fat any food material in excess of these needs. Fat and carbohydrates and 

 excess protein over the protein requirements of the body, are used for 

 energy and fat production. Some protein and ash are used for the repair 

 work and for the new material added to the body in the case of the growing 

 animal. 



A ration is the amount of food that is fed to an animal in twenty-four 

 hours for the above needs. The needs as to digestible protein, digestible 

 carbohydrates, and digestible fat for our animals have been carefully 

 calculated. Estimating the amount of food to meet these needs is called 

 computing a balanced ration. 



It has been found that there is a certain relation between the necessary 

 amount of protein and of carbohydrates and fat in a ration. This relation 

 has been called the nutritive ratio. The ratio is expressed between one 

 pound of digestible protein and the necessary number of pounds of digesti- 

 ble carbohydrates and digestible fat. When the first term of the ratio is 

 expressed as one, the second term is found by multiplying the fat by i\, 

 adding to it the carbohydrates, and dividing this amount by the protein. 

 The digestible fat is multiplied by 2j because fat is considered to yield 

 to the body 2\ times as much energy as carbohydrates. 



For dairy cows, it has been found that a nutritive ratio between 1 : 5 

 and 1 : 6 seems to give the best results in milk flow. 



To conclude: When we wish to compute a ration for a dairy cow 

 weighing about one thousand pounds, we try to furnish suitable food in 

 sufficient quantity to yield about twenty-four pounds of dry matter, in 

 which the relation of the protein to the carbohydrates plus 2j times the 

 fat is as 1:5 or 1:6. 



7. The breeds of cows are mentioned in some detail in the article in 

 this number of the leaflet on the colors of cows. In order of richness of 

 milk, the dairy breeds rank as follows: Guernsey, Jersey, Ayrshire, and 

 Holstein. The milk of the Guernsey and the Jersey tests 5 per cent to 6 

 per cent of butter-fat. The products of the Guernsey are a golden yellow; 

 the products of the Jersey a somewhat lighter yellow, or cream color. 

 The milk of the Ayrshire will average about 4 per cent of butter-fat, while 

 the Holstein gives milk testing on the average about 3.5 per cent butter- 

 fat. 



The Shorthorn probably is held in higher favor in the United States 

 than the other beef breeds, with the Hereford second; the Aberdeen- 

 Angus stands third and the Galloway fourth. 



New York is primarily a dairy State. Very little beef is raised in this 

 State except, perhaps, in the western part. Most of the beef consumed is 

 imported into the State from the great western markets. 



