3 Segmental Aplasia of Mullerian Duct

Transcript

Dear Veterinarians,

Good day! and today we are going to discuss segmental aplasia of the Mullerian duct or paramesonephric duct. So how these failures will affect the entire reproductive system? We will discuss. In the last class, we have discussed some of the anomalies in the uterus, so in this class, we are going to discuss again the failure of fusion of the Mullerian duct which resulted in the segmental aplasia of the reproductive tract.

So, in that first one is Segmental Aplasia or Hypoplasia of the Uterus: So, these defects are mostly hereditary in origin, and some may be congenital. So how does it happen? Because the Mullerian Duct has to be fused at the time of embryonic development so that the entire tubular structure will be formed accordingly.If the tube or Mullerian duct or paramesonephric duct failed to fuse means, either one of the tubular tract or the part of the uterus or part of the vagina or part of the cervix may be absent. Segmental aplasia of the uterine tube is very rare. The most severely affected cattle with Segmental aplasia of the paramesonephric duct are sterile due to the bilateral nature of the defects. These may be characterized by hymenal constriction; absence of either the cranial part of the vagina or the cervix or the uterine body, including the part of the horns, and cystic dilation of the uterine horns due to a narrow band of aplasia or a defect nearby the uterine body. More commonly just the apices of the uterine horns containing yellow, tan to dark reddish-brown mucus are present because these secretions may be accumulated inside and the secretion will be changed like these in due course of time. This cystic apical dilation may vary from the size of the horn to the approximate size of a four-month pregnant uterus containing a few ml of or gallon or even more thick gummy or inspissated mucus will be present in the uterus. so, you can very well see this image, the congenital absence of one uterine on resulting in the dilation of the cyst or the endometrial glands inside the developed uterine horn and finally end up with the accumulation of the mucus or inspissated mucus. so, this is about the Segmental aplasia of the uterus or hypoplasia of the uterus.

So next is Segmental aplasia of the Cervix with secondary Hydrometra: So, this is also a genetic or congenital anomaly of the cervix of the cattle not uncommon. Segmental aplasia may rarely occur, resulting in mucometra or a cystic enlargement of the cervix. A high incidence of developmental defects of the paramesonephric duct system is associated with infertility and sterility especially in cattle like Jersey and Shorthorn heifers. Besides segmental uterine aplasia, infertile heifers had sacculations that range from 1-4 centimeters in diameter and diverticulums ranging from 1-2 centimeters in deep, and dilation of the cervix due to the defects at the 3rd or 4th cervical rings. These defects are invariably filled with thick mucus and most affected heifers will result in a conception failure. These may often be diagnosed by rectal palpation of the cervix aided by a small metal probe such as a uterine catheter.

The next one is Segmental aplasia or Hypoplasia of the Vagina: The vagina is usually short and narrow in such condition or may have an enlarged or dilated caudal portion containing mucus or occasionally pus and submucous vaginal channels may be present. These cordlike structures are considered to be primitive vestiges of arrested development of the Mullerian ducts. They might be vestiges of the primitive Wolffian ducts also. In rare instances, there is a marked arrest in development, aplasia, or hypoplasia of the vagina and Mullerian duct system characterized by a lack of normal vagina, cervix, or uterus.

White Heifer disease with imperforate hymen: So, this is a classical form of failure of Mullerian duct or paramesonephric duct. So segmental aplasia of the Mullerian or paramesonephric ducts and especially an imperforate hymen have been called “White heifer disease”, so why was the name White heifer diseases coined? Because the defect is more correlated with white color, especially this condition is more commonly observed in Shorthorn cattle, the coat color also is white, so the name is White Heifer disease. So especially the Mullerian ducts fuse and develop in the bovine embryo at the time of embryo when the embryo is 5-15 centimeters in length or around day 35-120 days of age. So, during this embryonic stage, the Mullerian duct will fuse so that it will follow the regular development of the tubular structure, especially the entire reproductive tract. So White heifer disease was so named because it occurs most commonly in White heifers of the Shorthorn breed. As I told you, this condition is considered to be caused by a single, recessive, sex-limited gene with linkage to the gene for white color, so the condition called arrested development of the Mullerian ducts occurred in the Holstein herd also it’s mainly due to the inbreeding of a valuable sire upon his own daughters. so, because of inbreeding the white heifer’s disease also occurred in the Holstein herd.

So, you can see these images, the abnormality of the tubular structure because of cystic dilatation, the secretion will be getting accumulated, and it will stay, and it cannot be evacuated because of the hymenal constriction.

So Imperforate Hymen: the hymenal constriction also is common to these animals may be fertile or infertile, usually the latter, with prolonged intervals between estrus periods and repeated services per conception because conception cannot occur if ovulation takes place on the side of the abnormal horn and the normal involution of the Corpus luteum CL may not occur due to prostaglandin deficiency caused by the missing uterine horn or arrested development of uterine horn.

The heredity nature of these defects of the tubular portion of the bovine genital tract and the danger of their spread by artificial insemination (AI) bulls are also noted. So, you can see this image, imperforate hymen, secretion will be accumulated in the uterus, and it results in the Mucometra or Mucocervix or Mucovagina also.

So, Summary of Day 3 lectures,

Segmental aplasia or Hypoplasia of Uterus,

Segmental aplasia of Cervix with secondary hydrometra,

Segmental aplasia or Hypoplasia of the Vagina, and

White heifer disease with an imperforate hymen.

So, with this third-day lecture, I conclude, and

Thank you very much.