THE BREEDING SEASON 57 



activity for a certain period and the reproductive organs 

 gradually develop until at a certain age, or stage of devel- 

 opment, the essential organs are matured and begin 

 to develop perfect germ-cells. The stage of develop- 

 ment when the ovaries of the female produce perfect 

 eggs is called the period of puberty and represents the 

 beginning of the breeding season. The arrival of puberty 

 in the female is accompanied by the ripening of the first 

 ovum or egg and the appearance of the oestrum or heat. 

 The beginning of puberty in the female is marked by 

 certain characteristic changes. The mammary glands 

 increase in size, the general activities of the body are 

 accelerated and the animal performs certain actions that 

 are peculiar to the period of the oestrum or heat. The 

 coming of puberty in the male is likewise associated with 

 certain bodily changes which are well recognized by the 

 practical breeder. In the stallion, the neck, and partic- 

 ularly the crest develops, and the forequarters generally 

 are relatively better developed than the hindquarters. 

 The most significant changes however, are physiological. 

 The entire system assumes a state of greater activity. 

 Not only the generative system is concerned in this change 

 but all organs and functions of the body become more 

 active. In the bull, the external and visible changes 

 are an enlarging and thickening of the horns, and thicken- 

 ing and enlarging of the neck and crest. The increased 

 activity of males is indicated by greater restlessness, 

 irritability and the development of a pugnacious tendency. 

 Bulls and stallions often become vicious and unmanage- 

 able and engage in deadly struggles for supremacy. 

 These contests are also common among the males of wild 

 animals. Such battles have been observed as common 

 among stags and wild stallions. 



