36 PRINCIPLES OF STOCK-BREEDING. 



good illustration of the importance, to the breeder, of 

 a knowledge of all the details of structure and confor- 

 mation of the animal system, and the relations of 

 peculiarities of form to strength and constitutional 

 vigor. 



The offspring of animals that are very young, with 

 a system immature or imperfectly developed, or of 

 those that have had their constitution impaired by 

 abuse or overwork, will inherit a condition of the sys- 

 tem that predisposes to attacks of disease from slight 

 exciting causes. 



The effects may not be observed in all cases in a 

 single generation, but, if the practice of breeding from 

 such imperfect organizations is continued for several 

 successive generations, the most unfavorable results 

 may be produced. 



It is stated that "precocious marriages are not only 

 less fertile, but the children also which are the result 

 of them have an increased rate of mortality." l 



Dr. Duncan adds " the evidence of two gentlemen 

 skilled in the breeding of lambs and calves. They 

 say that the mortality of the young of these animals, 

 when the mothers are immature, is much greater than 

 when they are well grown." 



" One of them says : ' Taking the first lamb from 

 ewes at one year old has in almost every case failed 

 to be remunerative, owing to the frequent death of 

 the lambs.' The same may be said of young heifers, 

 though the mortality of the offspring may not be so 

 marked as in that of sheep." a 



1 Dr. Duncan, " Fecundity, Fertility, and Sterility," p. 38. 

 * Ibid., p. 390. 



