76 THE LAW OF BIRTHS AND DEATHS 



of energy tends to proportion itself to the amount used. 

 When the mare is first turned out to grass she will be in 

 the high condition which comes of regular work and high 

 feeding. The system will for a time continue to produce 

 energy from its own resources on the same scale as before. 

 Not being used, it will accumulate, and for some time 

 the animal's system will be highly charged. The abate- 

 ment will be gradual. After a time, not being used, and 

 owing to the very bulky and relatively innutritions food, 

 the supply will abate and the animal will become more 

 fertile. This accumulation of energy is seen in horses 

 which have been confined to the stable for a few days. 

 When first brought out they are very " fresh " and 

 often dangerous to drive until the surplus energy is 

 worked off. 



" Nervous, vicious animals are not so likely to breed 

 as those of milder temperament. Aged animals, especially 

 mares that have not been bred for some time, are extremely 

 difficult to impregnate. This is well illustrated in the 

 difficulty experienced in breeding mares that have been 

 used for racing until they are ten or twelve years old. 

 A large percentage of them fail to become pregnant. 

 Mares that have been bred frequently often will continue 

 to breed after they are twenty years of age. Fat animals 

 are seldom good breeders, and it is often difficult to im- 

 pregnate them. Animals intended for breeding should 

 be in very moderate flesh. Active exercise just before 

 the animal is fed is conducive to fertilisation." * 



Vicious animals are usually nervous animals which 

 have been spoiled when young through mismanagement. 

 Nervousness is one of the signs of a highly developed 

 nervous system. Witness the difference in this respect 

 between the highly strung race-horse and the placid 

 1 The Diseases oj Animals, Mayo. 



