TESTED DAIRY ANIMALS CONNECTICUT . 243 



feeding of the offspring. Many generations of selection and breeding by 

 man have prolonged the period of activity of these organs in the dairy cow, 

 but the beginning is always a function of reproduction, which must occur 

 with considerable regularity in profitable cows. In order that this may occur 

 with the least tax upon the general vigor and activity of the cow, she should 

 have broad hips and a high pelvic arch, furnishing ample room for the young 

 before birth and providing for its easy delivery. 



Heart and lungs. The chest should be deep, providing room for generous 

 sized heart and lungs. These organs, vital in every animal, are required 

 to do more than ordinary work in the dairy cow. The digestion of a large 

 amount of food and its conversion into milk require an expenditure of energy 

 and vitality equal to that expended in the performance of hard work. 

 Therefore, there should be a vigorous circulation of blood and ample pro- 

 vision for its purification and for a large supply of oxygen. 



The nerve system. The digestive tract prepares the food for assimilation 

 into the tissues, the udder elaborates the milk, the heart forces the blood 

 with its load of food and oxygen through the body, the lungs supply oxygen 

 to the blood and remove from it the products of the oxidation which takes 

 place in the body ; but the brain and nerve system are concerned in all these 

 operations. Through the influence of this system the aotivities of all the 

 organs are aroused, guided, controlled and harmonized. In the cow the 

 heart and lungs are ever active. The digestion, absorption and assimilation 

 of food, and perhaps the mysterious elaboration of milk, are constantly 

 going on. Collier estimates that a cow giving an average quantity of milk 

 produces, on an average, 138,210,000 fat globules per second during each 

 24 hours. This and the secretion of the other constituents of the milk 

 illustrate the amount of activity in the milk organs alone, and suggest the 

 need of a highly developed nerve system. The more pronounced of the 

 outward signs that indicate this nerve development are a bright, lively, and 

 prominent eye, this prominence causing a dished face; a wide forehead; 

 a wide junction of the skull and spinal column, indicating a large brain; 

 a large prominent backbone, giving room for a well developed spinal cord; 

 a long slim tail; and considerable energy and vigor and style of action. 



The correlation of parts. It is to be observed that further help in the 

 study of dairy cows is an understanding of the reciprocal relations between 

 the different parts of the body. It is in accordance with this correlation that 

 the parts of the body here spoken of as less essential may be said to be indi- 

 rectly concerned in the production of milk; for the same food can not be used 

 at the same time for both forming flesh and producing milk; hence the smaller 

 the amount of food used in the formation of tissues of these less essential 

 parts, the larger the amount that will be left to be converted into milk. 



Less essential parts. The energy of the dairy cow is directed as com- 

 pletely as possible toward the production of milk and butter. The tendency 

 to produce milk has been increased as much as possible by breeding, in- 

 heritance and development; and likewise, the tendency to lay on flesh has 



