Age of the Domestic Animals, 



INTRODUCTION. 



Age is defined by Webster as " the whole duration of a 

 being," or " that part of the duration of a being which is 

 between its beginning and any given time." It is not to be 

 confounded with the term as appUed to the various periods or 

 epochs of an animal's life, as the juvenile, adult, and senile, 

 which correspond to organic metamorphosis of distinct character 

 and to a marked cliange in tlie degree of functional activity. 

 The age of the domesticated animals is a matter of great impor- 

 tance in agricultural commerce, as, in the limited period during 

 wliich each of them is individually useful, a com})aratively short 

 time diminishes greatly the extent of usefulness to which each 

 can be put, and consequently lowers its value as an investment. 

 Tlie means which enable us to judge the age of an animal are 

 based upon certain anatomical and physiological changes which 

 occur in the course of the development of the newborn to the 

 adult animal, and in the deterioration of it from its period of 

 perfection to the decrepitude of its last years. These changes 

 are constant, and, while the animal retains its general form and 

 the tissues are chemically identical, there is a constant renewal 

 of the molecules, which is rapid early in life and slower later. 

 Age can be divided into tliree periods : First, juvenile, or tlie 

 period of growth, which extends from the birth of the animal 

 to its full development, during which it is gaining in size, in 

 strength, and in intelligence, and is constantly increasing in its 

 (qualities and value. Second, adult, or the stationarij period ; in 

 this the animal is at its best ; it has every organ complete in size 

 and perfect in function, working in perfect harmony with the 

 rest of the body ; its intellect has the most complete control 

 over its perfectly organized muscles, digestive tract, and other 



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