MANAGEMENT OF DAIRY CATTLE 225 



lump in the upper part of the teat, which seems to drop down 

 into the opening when drawing the milk. In this latter case, 

 or when the use of an ordinary dilating plug is not sufficient, the 

 bistoury should be employed. This is an instrument that is 

 passed into the teat opening, and then by means of a screw 

 a small knife edge is projected on one side at the upper end, 

 and the instrument is then withdrawn. The knife blade cuts 

 the side of the teat duct and the surrounding muscles. An or- 





FIG. 44. Instruments for treatment of udder troubles, a, b, milk tubes; 

 c, lead teat plug; d, teat expander; e, teat opener; /, teat slitter or 

 bistoury. 



dinary teat plug is then kept in the opening, except at time of 

 milking, until the cut heals. This leaves the opening enlarged 

 permanently. 



Sterilizing Instruments. Before a milk tube, a teat plug, 

 the bistoury, or any instrument is inserted in the opening of a 

 cow's teat, it must be thoroughly disinfected. If this is not 

 done, germs will gain access to the udder, which will cause in- 

 flammation that may ruin the animal. Instruments should 

 Q 



