8 BULLETIN 106, U. S. DEPARTMENT OF AGRICULTURE. 
covered with masses of stringy, semiopaque mucus, or there may be 
seen small opaque flakes of muco-pus resting upon the mucosa. 
The nodules now multiply with astonishing rapidity. Their 
arrangement in parallel longitudinal rows becomes well marked, the 
nodules being crowded into close contact with each other upon the 
summits of the swollen, hypertrophied mucous rugse. The nodules 
frequently lose their transparency and assume a deep-red color, and 
the malady assumes in every way a more decisive clinical aspect of 
important disease. Even then, however, it is not noticeable in so 
far as the general health of the heifer is concerned. 
The intensity of the symptoms increases for a few days, remains 
static for a time, and then tends to recede slightly, but the betterment 
makes no appreciable approach to the status which had been main- 
tained prior to copulation — a fact which emphasizes strongly its 
essentially venereal character. 
Should the heifer become pregnant at the first service, the irritation 
may abate slightly and slowly for a time, but the nodules remain 
prominent and approximately as numerous as ever, and the clinical 
evidences of disease remain essentially static, at one period apparently 
improved, at another worse, until near the time for parturition, when 
the vulvar mucosa becomes more reddened. A marked edema 
(parturient edema) then appears, the nodules are covered over and 
are no longer visible. Usually they may still be felt upon careful 
palpation. In many cases of abortion the edema of the vulvar 
*$ mucosa is essentially the same as if parturition had occurred. Should 
parturition or abortion be followed by retained placenta and 
chronic metritis or pyometra, the nodules continue masked by the 
persisting edema so long as serious uterine disease continues. Other- 
wise, with the gradual disappearance of the edema of the mucosa the 
nodules slowly come again into view. 
If the heifer fails to conceive at the first copulation, when the next 
estrual period arrives and copulation occurs, should the sterility be 
refractory, the symptoms tend to increase, so that sterile heifers are 
quite generally among the worst clinical cases of the disease in a herd. 
The symptoms of the disease retain approximately the average 
intensity acquired during the first pregnancy through the second and 
third pregnancies, when the severity of the malady gradually abates. 
When the cow reaches 8 to 9 years of age, and her sixth or seventh 
pregnancy, the decrease in the intensity of the disease generally 
becomes quite marked, the nodules are fewer, less prominent, and 
more transparent, the irritation and injection of the vaginal mucosa 
is definitely decreased, and the muco-purulent discharge has largely 
abated. With advancing age, the vulvar mucosa becomes pale 
yellowish, or bluish-yellow, the nodules disappear, and the clinical 
evidences of the disease commonly vanish when the cow has reached 
the age of 12 to 15 years. 
