METHODS OP RESTRAINT AND COMMON OPERATIONS 259 



only in young horses, because the patient must be confined for 

 six or eight weeks after the operation. Tenotomy is the only 

 method of treating severe "knuckling" due to contraction of 

 the tendons. As a means of relieving stringhalt, the results, 

 although not 100 per cent, perfect, justify the operation. 



TRACHEOTOMY 



Tracheotomy is an operation to provide a direct entrance for 

 air into the trachea. It is performed for the following purposes : 



To avert suffocation threatened by swellings or other obstruc- 

 tions in the upper air-passages; to restore to usefulness animals 

 that have difficulty in breathing produced by stenosis of the 

 upper air-passages; to remove foreign bodies from the trachea. 



The operation is best performed on the standing animal with 

 the head extended. An opening is made into the trachea by 

 means of an incision. There is then inserted a special trachea 

 tube, with a fine wire-gauze covering to prevent dust particles in 

 the air from passing through. This tube is to be removed and 

 cleansed daily as long as its use is necessary. 



ARTIFICIAL INSEMINATION 



The impregnator is used in horse-breeding as a practical and 

 satisfactory means of breeding mares that have been difficult or 

 even impossible to breed by direct service. As a means of breed- 

 ing several mares at one service of the stallion, it has extended his 

 use to more mares than would otherwise be possible. It is 

 attempted only when the mare is in heat. 



In Bulletin 93 of the Oklahoma Experiment Station, Dr. L. L. 

 Lewis discusses the various forms of instruments employed for 

 artificial insemination and their methods of use. He emphasizes 

 the necessity of keeping all instruments scrupulously clean. As 

 the sperm cells are very abundant in the semen, it is not necessary 

 to place a large amount in the womb. Experiments show that 

 contact with the air seems to have little effect upon the vitality of 

 the sperm cells. Direct sunlight is injurious to them, and semen 

 left in the sun soon loses its vitality. The life of the cells is short 

 even when protected, as in normal copulation, so an effort must 

 be made to introduce the semen into the womb without un- 

 necessary exposure or delay. 



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