BREEDS AND THE PRINCIPLES OF BREEDING. 429 



between such an animal and one brought in at three years old, when they reach the age of 

 four or five. 



As to the age of the bull when put to service, our theory and practice are widely dif 

 ferent; for, while most intelligent farmers are ready to admit that one year is too young, 

 that the system is not mature, that the animal is not developed, and ought not to be used, 

 they do, in fact, use yearling bulls far more commonly than older ones. If well fed and 

 thrifty, we should not object to a limited use of a bull at fifteen months, and from eighteen 

 months and onward more freely, in getting dairy stock and stock for beef. For getting 

 working cattle, or animals for labor, the bull should be at least two years or two years and a 

 half old. The bull is better to be worked ; and, if it were our custom to use all our bulls 

 more or less in the yoke, they would undoubtedly be all the better for it. 



The age at which different animals should be bred will vary according to their maturing 

 qualities, and other conditions, a subject which has already been treated in connection with 

 the separate description, etc., of different kinds of farm stock. We have aimed in this con 

 nection to give some of the more important general rules and principles in the art of breed 

 ing, especial directions being found in connection with each special department of domestic 

 animals. 



Controlling the Sex of Offspring. There has been much controversy on this 

 subject, and many experiments have been cited to prove the opposing theories advanced. The 

 subject of producing either sex at will interested the ancients as well as the present genera 

 tion, and many rules denominated infallible were laid down by them, some of which were 

 most whimsical and ridiculous. According to Professor Thury of Geneva, Dr. Naphy, and 

 other eminent authorities, when conception takes place in the early stage of the period of 

 the oestrum termed &quot;heat,&quot; the result is a female, but if conception takes place late in this 

 period, or when it is passing off, the result is a male. This theory has gained much 

 favor, yet numerous instances from equally reliable authorities might be cited to prove pre 

 cisely the reverse in results. Darwin states in reference to this view of the subject, that 

 recent observations discountenance it. 



Dr. Sturtevant says respecting it : &quot; In my own experiments in this direction, I have 

 obtained no confirmation, and I know of careful and reliable men who claim good results 

 from the same theory in an exactly opposite direction, viz., that the first signs of heat influence 

 a male conception, the last a female conception. 



Prepotency seems one of the best determined incidents recorded in this relation. In 

 several species of domesticated or cultivated animals (1 believe in all), writes Thomas Knight, 

 particular females are found to produce a very large majority, and sometimes all their off 

 spring, of the same sex; and I have proved repeatedly that by dividing a herd of thirty cows 

 into three equal parts, I could calculate with confidence upon a large majority of females 

 from one part, of males from another, and upon nearly an equal number of males and females 

 from the remainder. I frequently endeavored to change these habits, by changing the male, 

 but always without success; and I have in some instances observed the offspring of one sex, 

 though obtained from different males, to exceed those of the others in the proportion of five 

 or six, and even seven, to one. My own experience in the Waushakum Herd of Ayrshires 

 is confirmatory of this statement, as are also the materials relating to births gathered with 

 great labor from the Ayrshire Herd Book.&quot; 



Dr. George Watt, of Ohio, an old physician and extensive breeder, after experiments 

 extending over a period of fifty years, also arrives at an opinion directly the opposite of that 

 of Professor Thury. 



Notwithstanding the vast number of experiments that have been tried to ascertain the 

 law which governs the sex of animals, no satisfactory result has been obtained. But it has 

 been observed that the most vigorous parent will generally govern the sex; that is, that the 



