DISEASES OF THE NEW^-BORN ANIMAL. 



I. Infections of the New-Born. 



At the time of birth there necessarily occurs a wound of the 

 new-born consisting of a divi.sion of the umbiHc cord. The 

 division of the cord may occur just prior to the completion of 

 the expulsion of the fetus, after a portion of the fetal body has 

 passed beyond the vulva, as is usually the case in those animals 

 having a very short umbilic cord, like the cow and other rumi- 

 nants. In other animals, where the umbilic cord is long, as in 

 the mare, the fetus is usually wholly expelled before rupture of 

 the cord takes place. In any animal, though extremely im- 

 probable in ruminants, the entire fetal placenta may follow the 

 expulsion of the fetus immediately, and the cord remain intact. 

 As a general rule this presages the death of the fetus in the 

 larger animals, because the separation of the fetal from the ma- 

 ternal placenta has advanced to such a degree before the expul- 

 sion of the young that it di.sturbs the aeration of its blood and 

 leads to its death by strangling. In multiparous animals, where 

 the fetal placenta must necessarily follow each fetus before a 

 succeeding one can be expelled, the fetal membranes very fre- 

 quently remain attached to the fetus by the umbilic cord, which 

 is divided by the mother with the teeth. In other young which 

 may be born with the navel cord xinbroken, its rupture very fre- 

 quently results from the struggles of the young animal, or may 

 be brought about by the mother. 



The point at which the navel cord divides is usually very close 

 to the umbilicus — in the foal and calf from one to three inches — 

 in which region the cord is normally smaller and weaker than at 

 other parts. After the rupture, the normal course of events 

 consists of the retraction of the two umbilic arteries and of the 

 urachus, upward and backward into the peritoneal cavity, draw- 

 ing with them, in their retreat, portions of the loose connective 

 tissue which immediately surround them. In this retraction the 

 walls of the vessels become thickened, while their lumen becomes 

 correspondingly decreased, thus preventing the escape of blood 

 from the arteries or of urine from the urachus. The escape of 

 urine or of blood is further safeguarded by the connective tissue, 

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