238 FOOD OF FARM ANIMALS 



Small amounts of salt must be fed to farm animals in 

 most regions. The farmer in the British Isles does not 

 need to give salt to his cattle, for the salt air from the 

 sea gives a saltness to the pasture grasses. 



Protein is the part of food that contains nitrogen, 

 and is the muscle-forming substance in food. Albumin 

 in the white of egg, myosin in lean meat, casein in the 

 curd of milk, and gluten in wheat grain are familiar 

 examples of protein. More or less protein is found in 

 all vegetable and animal food products. 



Starch and sugar are common examples of carbo- 

 hydrates. The carbohydrates supply energy to ani- 

 mals, in the form of heat and work. Carbohydrates 

 may be converted by the animals into fat. An animal 

 that fattens easily has the power to convert the sugar 

 and starch of its food into fat. 



Fats. The lard of hogs, the tallow of cattle and 

 sheep, and butter are well-known fats. In vegetable 

 foods there is some fat. Nuts and corn contain con- 

 siderable fat, and cottonseed oil and olive oil are oily 

 fats. The fat in the grain and other foods has the 

 same use in the body of an animal that starch and 

 sugar have. 



A balanced ration for an animal is the right amount 

 of food containing the proper proportions of proteins, 

 carbohydrates, and fat. For example, a cow that 

 weighs 1000 pounds and gives 22 pounds of milk per day 

 ought to eat about 29 pounds (dry weight) of food in 

 which there are 2.5 pounds of protein, 13 pounds of 



