MATS"UAL OF CATTLE-FEEDINa. 199 



causing increased drinking, and second, by absorbing lieat 

 from tlie body by its evaporation, just as water sprinkled 

 on the floor on a hot day absorbs heat as it evaporates, and 

 so cools the room. Every such loss of heat is equivalent 

 to a loss of substance, since the heat is produced by the 

 oxidation of the materials of the body or of the food. Too 

 high a temperature is also liable to make the animals rest- 

 less and diminish their appetite. A medium temperature 

 of from 55° to 70° F. is the most favorable for fattening. 



Muscular Exertion, as we shall see more in detail in 

 the next chapter, increases the consumption of fat very 

 considerably. Too much movement by fattening or milk- 

 ing animals is therefore to be avoided. This is true not 

 only of outward motions but of the internal motions of the 

 hody in digestion, etc. If a very bulky fodder be given, 

 the increased work of moving it in and through the diges- 

 tive apparatus cannot but have its influence in increasing 

 the oxidation and destruction of fat. Doubtless one of the 

 advantages of concentrated and easily-digestible fodders is 

 the saving in internal work which they eftect. 



The Amount of Oxygen taken up by the Blood 

 is a not unimportant factor in the production of fat. The 

 decompositions which take place in the body are, as we 

 have already seen, vital processes, and the taking up of 

 oxygen is a consequence and not a cause of them. 



At the same time, the maximum amount of oxygen that 

 can be introduced into the system is determined by the 

 amount of blood and its content of hsemoglobin, this sul)- 

 stance being the active agent in taking up the gas, and 

 tjiis, of course, sets a limit to the amount of matter that can 

 be oxidized in the system. Consequently a small amount 

 of blood and a small proportion of haemoglobin are condi- 

 tions favorable for the production of fat. 



