The Brood Mare 281 



containing the spermatozoa into the vagina of the mare, 

 from whence the spermatozoa pass into the uterus and 

 from there into the Fallopian tube where they meet the 

 ovum or female cells and impregnation proper takes place. 

 This may not occur for several hours after copulation. 

 The mare produces one, and sometimes more than one 

 ovum during the period of heat, while the semen ejected 

 by the horse contains hundreds of the microscopic sperm- 

 cells, and only one of which may unite with the ovum to 

 produce the colt. Thus the horse at each act of copula- 

 tion produces many more spermatozoa than are actually 

 needed, provided of course that he is a normal, healthy 

 horse. The idea in artificial impregnation is to collect 

 some of these spermatozoa which are not needed by the 

 mare bred, and transfer them to other mares. If prop- 

 erly conducted this will produce exactly the same im- 

 pregnation as if the mares were bred directly by the stal- 

 lion. 



The breeding bag is a rubber bag which is tied on to the 

 end of the penis. When the penis is withdrawn after 

 service, the bag with the ejected semen comes back with 

 it. The bag is then placed in warm water, 95° to 101° 

 temperature. A syringe is filled with the fluid, and emp- 

 tied into the vagina of the mare. As only a part of the 

 fluid is used for one impregnation, a number of mares 

 may be bred from this one bag of semen. The objections 

 to this method are : stallions may refuse to serve with the 

 breeding bag attached ; the fluid may become contam- 

 inated with germs; the fluid may be exposed to the 

 light and the sperm-cells killed ; and lastly, the stallion, 

 even though it may not refuse at first, usually does refuse 

 to serve properly after the breeding bag has been used 

 for some time. 



