WHAT CONSTITUTES AN ADEQUATE RATION 105 



because of the absence of an essential or because of the presence of a 

 non-essential. It is futile, therefore, to try to look for a material 

 something, specific in the corn ration, that is causing difficulty with 

 pigs, so experience teaches us. We want to look for something that 

 is to be found somewhere else, and add it to the corn ration, and 

 thus overcome the difficulty. 



Balancing a Ration. When we balance rations we must re- 

 member that the demands of animals change. A young, growing 

 pig requires an entirely different ration than the same pig after it 

 has reached maturity and is ready to go to market. The brood sow 

 during gestation requires different feeding than the same sow dur- 

 ing the suckling period, and so on. The weather and external fac- 

 tors are of some importance, for instance, cold weather may have 

 its particular demands for heat-producing feeds. After all, there is 

 a great possibility of combinations that will work, and it is surpris- 

 ing how many good combinations there are when we come to study- 

 ing feeding. 



The making up and feeding of a swine ration may be compared 

 to the building of an automobile. We need building material to 

 make a pig, such as protein which makes up the muscle, part of 

 the bone, some of the hide, the hair, and so on ; calcium phosphate 

 or bone ash, which will help build the bone ; fat, which will act as 

 a bodily reserve, cushion, and perform other functions. These mate- 

 rials are necessary. In the automobile we need steel, iron, wood 

 and other materials. The pig needs fuel or feed to "keep him 

 going.*' It is supplied by corn, milk, alfalfa, rape, and so on, the 

 auto engine taking gasoline. The pig takes water and air to cool 

 himself, and the engine uses for the same purpose the same mate- 

 rial. The pig has nerves in his body to transmit his impulses ; the 

 automobile has electric wires. The pig has lungs to mix the gasses, 

 and take out of them what is necessary, while the engine has its 

 carburetor. The pig has various organs that tend to keep things in 

 tune, rightly timed, such as certain portions of the brain and so 

 on, and the engine has a timer. The pig has nerve-endings in the 

 muscle and in other tissues that really may, in a sense, be consid- 

 ered as a seat of activity, whereas the engine has spark plugs, 

 where the vital spark that sets the whole thing in motion is set off. 



The engine to run right must be in perfect order, all parts com- 

 plete. So a ration to serve the highest function must be almost 

 perfectly compounded all factors must be present and in the prop- 

 er proportion if the pig fed thereon is to gain the fastest and in 

 the least possible time. But what are the essential factors of grow- 

 ing rations for pigs ? 



The Function of Water. First, water water in abundance. 

 Water performs among others these functions: Supplies building 

 material ; regulates the heat through evaporation, ingestion, and ex- 

 cretion ; acts as a solvent, thus facilitating chewing and swallowing. 

 Water furnishes some 68 or more pounds out of pigs and other ani- 



