DISEASES OF CATTLE 209 



CLOSURE OF THE MILK DUCT BY A MEMBRANE. 



In this form the duct of the teat is closed by the constriction of 

 its lining membrane at one point, usually without thickening. The 

 closure usually takes place while the cow is dry; otherwise its prog- 

 ress is gradual, and for a time the milk may still be pressed through 

 slowly. In such a case, if left at rest, the lower part of the teat fills 

 up and the milk flows in a full stream at the first pressure, but after 

 this it will not fill up again without sufficient time for it to filter 

 through. This is to be cut open by the hidden bistoury, which may 

 be first passed through the opening of the membrane, if such exists. 

 If not it may be bored through, or it may be pressed up against the 

 membrane at one side of the teat and opened toward the center, so 

 as to cut its way through. Incisions should be made in at least two 

 opposite directions, and the edges may be then held apart by wear- 

 ing the spring dilator until healing has been completed. 



In all cases of operations on the teats the instruments must be 

 thoroughly disinfected with hot water, or by dipping in carbolic acid 

 and then in water that has been boiled. 



OPENING IN THE SIDE OF THE TEAT (MILK FISTULA). 



This may occur from wounds penetrating the milk duct and 

 failing to close, or it may be congenital, and then very often it leads 

 to a distinct milk duct and an independent portion of the gland. In 

 the first form it is only necessary to dissect away the skin leading into 

 the opening for some distance down, to close the orifice with stitches, 

 and to cover the whole with collodion. A teat tube or spring dilator 

 may be worn to drain off the milk and prevent distention and reopen- 

 ing of the orifice. In case of an independent milk duct and gland 

 one or two courses may be selected to open the one duct into the 

 other by incision and then close the offending opening, or to inject 

 the superfluous gland through its duct with a caustic solution, so as 

 to destroy its secreting power. In both cases it is desirable to wait 

 until the cow goes dry. 



DISEASES OF YOUNG CALVES. 



SUSPENDED BREATHING. 



The moment the circulation through the navel string is stopped 

 the blood of the calf begins to get overcharged with carbon dioxid 

 (C0 2 ), and unless breathing is speedily established death promptly 

 follows. Fortunately the desire to breathe, roused by the circulation 

 of the venous blood and the reflex action from the wet and chilling 

 skin, usually at once starts the contractions of the diaphragm and life 

 is insured. Among the obstacles to breathing may be named suf- 

 focation before or during birth from compression of the navel cord 

 and the arrest of its circulation; the detachment of the fetal mem- 

 branes from the womb before the calf is born ; a too free communi- 

 cation between the two auricles of the heart (foramen ovale) by 

 which the nonaerated blood has mixed too abundantly with the 

 aerated and induced debility and profound weakness ; a condition of 

 ill health and debility of the calf as a result of semistarvation, over- 

 work, or disease of the cow; fainting in such debilitated calf when 



