II. 



BREEDING. 



The art of raising domestic animals lias attained a great 

 degree of perfection, due to the recognition of certain principles 

 in physiology. This subject has been studied as a science and 

 practiced as an art for centuries, but there yet remains room for 

 improvement. It will not be expected that the author will dwell 

 minutely or at length upon the formation and growth of the 

 fetal strue-tures and trace them separately from their origin to 

 their completion at the birth of the fetal animal. 



Menstruation, or period of puberty, in the mare and cow is 

 reckoned at the age of ons to two years, in most cases; but the 

 filly should not be bred until she is three or four years of age, 

 and even older, if she is immature. The cow may be bred at two 

 years of age, or earlier, if well matured. There is, with few 

 exceptions, a periodical discharge of mucus from the vagina. 

 This discharge naturally follows the ripening and liberation of 

 an ovum, and continues in a great majority of cases from two to 

 four days; it recurs once in four or five weeks, and continues as 

 long as the female is capable of conceiving, or rather as long as 

 ova are developed. Menstruation is ovulation. When the geni- 

 tal organs are sufficiently developed, a germ cell, or ovum, is 

 evolved from its ovarian bed, and passes along the channel of the 

 fallopian tube into the uterine cavity; unless impregnated in its 

 course by meeting and mingling with the sperm cell of the 

 male, and fixed upon the wall of the utero-fallopian canal, it is 

 expelled through the vaginal passage, a process repeated every 

 four or five weeks in the mare and cow. At this time the nervous 

 system of females is sensitive, and it is the only time that copula- 

 tion is indulged in. Immediately before- and after this period, 

 conception is more likely to take place. The contests between 



(22) 



