l88 THE MANAGEMENT AND FEEDING OF CATTLE 



that the former will milk profitably for a longer term 

 of years. 



That such results should be expected would seem 

 reasonable, first, from the known fact that during the 

 rest period energy is stored up for future use, and, 

 recond, that a machine overtaxed wears out sooner than 

 one not thus overdriven. During the rest period the system 

 is fortified by increase in flesh and this, up to a reason- 

 able limit, brings with it increase in nerve power. It 

 stands to reason, therefore, that when the cow comes in 

 milk again she will be able to milk better than the cow 

 whose energies have been taxed by continuous milking. 

 The machine ; that is, the animal economy, is thus over- 

 taxed by incessant work. 



The influence of such continuous milking on the 

 progeny is also adverse. It diverts to the making of 

 milk at least a part of the nourishment that would 

 otherwise go to the fetus. All the food given to such 

 a 'cow is used in one of these ways, that is, in mainte- 

 nance, in making milk, and in nourishing the fetus. It 

 is very evident that the more it is diverted to one or 

 another of these purposes, the less will there be for the 

 others. This explains why a cow given rest usually 

 increases in flesh during the rest period, while a covV 

 milked continuously cannot make such increase. It also 

 explains why development in the young should be 

 Ijsnefited by a rest period in the dam before it is born. 

 It is reasonable to suppose that as pregnancy advances 

 Jie demands of the embryo on the support from the dam 

 continually increase. Continuous milking, therefore, 

 cannot but tend to a lowering of stamina, not only in 

 the dam, but also in the progeny. The duration of the 

 period of rest, therefore, is the only question that is 

 debatable. It will difi^er with different animals, and 

 should probably average not fewer than from eight to ten 

 weeks. It would seem reasonable to suppose that it 

 should be longest in the cows that milk most freely. 



