164 



FARMER'S CYCLOPEDIA OF LIVE STOCK 



gelatine capsules which are filled with 

 semen from the vagina of a mare just 

 served by a stallion and then intro- 

 duced at once in the uterus of other 

 mares from which colts are desired. 

 There appears to be no decided prefer- 

 ence in favor of either one of these meth- 

 ods, but some experience is required be- 

 fore the breeder becomes really skillful 

 in the practice of either method. 



Artificial impregnation has been used 

 a number of years by hundreds of farm- 

 ers and the results thus far obtained 

 are perfectly satisfactory in every re- 

 spect. The colts obtained by this meth- 

 od are of the usual size and vigor, so 

 that it may be confidently asserted that 

 no objection from this source may be 

 raised to the system of artificial impreg- 

 nation. 



The same system has also been used 

 with cattle, dogs and other animals. In 

 the case of registered animals, where the 

 name of the sire must be given, it is 

 simply stated in the herd-book that the 

 animal in question is the result of arti- 

 ficial impregnation from such and such 

 a sire. This is a simple solution of the 

 difficulty which occurred in the minds 

 of some breeders regarding the state- 

 ment of pedigree in the case of animals 

 bred in this manner. 



Mule breeding by artificial impreg- 

 nation — The system of artificial impreg- 

 nation is of peculiar value in mule breed- 

 ing. As is well known, many mares do 

 not take kindly to jacks and frequently 

 kick so violently that special breeding 

 chutes or some other means of restrain- 

 ing them must be adopted. Moreover, not 

 all jacks are keen in serving mares; in 

 fact, occasionally they refuse altogether 

 to do so. It is obvious, therefore, that the 

 system of artificial impregnation is of 

 great benefit in helping breeders over 

 this difficulty. It is merely necessary to 

 allow the jack to serve a jennet, after 

 which the semen is removed in an arti- 

 ficial impregnator and injected into the 

 uterus of mares from which mule colts 

 are desired. 



STERILITY IN ANIMALS 



Sterility or barrenness in animals may 

 be due to a variety of causes. In the 

 male it may be due to imperfect develop- 

 ment, inflammation or degeneration of 

 the testicles, malformation, paralysis or 

 growths on the penis, nervousness or the 

 presence of such diseases as azoturia, 

 failure of the testicles to descend, im- 



proper feeding, etc. In the female bar- 

 renness may be due to imperfect develop- 

 ment, tumors, or degeneration of the 

 ovary, catarrh of the uterus, nervous- 

 ness, a too fat or too poor condition, clo- 

 sure of the neck of the uterus, etc. In 

 mares sterility may affect 20 to 40 per 

 cent, in cows 20 to 30 per cent, in sheep 

 and goats about 5 per cent, in swine, 3 

 to 10 per cent, in poultry reliable data 

 are not available. 



Constitutional barrenness — It is evi- 

 dent from the above statement that 

 many cases of barrenness are of a consti- 

 tutional nature and can not be treated. 

 In curable cases the cause should be 

 sought and the proper remedy applied. 

 Within certain limits barrenness does 

 not depend on the age of the female. 

 The reproductive functions do not de- 

 velop until a certain age is reached and 

 disappear again at old age. The per- 

 centage of sterility may be higher when 

 too old or too young males are used. 

 Statistics collected for several years in 

 England with regard to pure and cross 

 bred sheep show that on an average 

 about 5 per cent are barren. Only about 

 2 per cent, however, were constitution- 

 ally barren. In fact much of the bar- 

 renness in domestic animals is prevent- 

 able. Breeding animals should be neith- 

 er too fat nor too poor, but must be . 

 kept in a moderately fat, vigorous con- 

 dition if the best offspring are desired. 



In cows and mares the neck of the 

 uterus may become hardened and swollen 

 so as to close the opening and exclude 

 the semen. This cause of barrenness 

 may easily be removed by dilating the 

 uterus. In mares this may be done with 

 the finger, while in cows it is usually 

 more difficult and may require the use 

 of a metallic dilator. In such cases the 

 operation should preferably be done by 

 a qualified veterinarian. A Danish in- 

 vestigator has recently found that in 

 high bred cows, the corpus luteum re- 

 mains on the surface of the ovary after 

 parturition, and prevents the occurrence 

 of heat or estrum. The removal of the 

 corpus luteum by a surgical operation is 

 followed shortly by the usual period of 

 heat. 



Conditions favoring fecundity — The 

 fecundity of our farm animals may be 

 greatly affected by the artificial condi- 

 tions of modern farming. In Indiana 

 it has been found that ewes too closely 

 confined without proper exercise become 



