4 Miscellaneous Hereditary Forms of Infertility

Transcript

Dear Veterinarian,

Good day! and today we are going to discuss about the Miscellaneous Hereditary forms of Infertility in bovines, so in that, we are going to discuss about Freemartinism, this is one of the common congenital anomalies which is encountered in the majority of bovine breeds. So Freemartinism is a distinct form of intersexuality due to vascular anastomosis of the adjacent chorioallantoic sacs of heterozygous fetuses in twin pregnancies. The majority of female fetuses in male/female twin pregnancies are affected. So vascular anastomosis occurs as early as 30 days of gestation. So, occurs when the blastodermic vesicles from each developing zygote meet and fuse in the uterus about day 18-20 of pregnancy, so it is possible for single born freemartins to occur if there is a death of the male twin of a heterozygous pair after the time of vascular fusion with the another being carried to term.

This has been demonstrated as a cause of infertility in heifers with apparently normal external genitalia but with sex chromosome chimerism that is a mixture of both female and male cells. The external genitalia freemartins may appear relatively normal. and

The clitoris is characteristically enlarged, and prominent and coarse hairs are present at the ventral commissure of the valva.

The internal genitalia is grossly abnormal.

The gonads are typically vestigial, although they undergo masculinization in mild cases.

So the structure is derived from the paramesonephric ducts are almost entirely absent or grossly hypoplastic.

In animals, with a significant degree of masculinization, the gonads resembled testes to the extent that their parenchyma contains recognizable tubules and interstitial tissue. The development of mesonephric (Wolffian)ducts is related to the degree of masculinization of the gonad. So, in extreme cases, well-developed epididymides, vas differentia, and Vesicular glands are also observed. More typically, the vestigial gonads of freemartins are devoid of oocytes and follicles and have parenchyma that consists largely of degenerating sex cords. You can absorb prominent clitoris and tuft of hair at the ventral commissure of the vulva, but these signs are not always reliable. and Freemartins can be identified on the basis of the length of the vagina and the absence of the cervix also So in the adult, the vagina is normally 30 centimeters in length compared with the 8-10 centimeter length of the vagina in Freemartin females. The rectal palpation will fail to identify the cervix because the cervix is absent in promoting freemartin females. So, in calves of the 1-4 weeks of age. the vagina is normally 13-15 centimeters in length as compared with 5-6 centimeters in a freemartin female calf. Diagnosis at this age can be made using Fincher’s test, so this is one of the tests which is very useful under field conditions, so you can use a blunt probe or blunt rod, which should be inserted initially at an angle of 45 degrees below the horizontal for 5 centimeters and then angled downwards to avoid impinging on the hymen.

We have encountered so many twin births in our surgical ward and most of the time we used to test then and there, so especially in twin foetus, in twin calf, one is male and another one is female means we usually observe the clinical signs like a tuft of the vulva, a tuft of vulval hair as soon as the prominent clitoris and simultaneously we use to do the Fincher’s test and accordingly we used to advise the farmer also for these conditions so that we can prevent as well as we can avoid such kind of sterile animal in the field conditions. See very well in these pictures, especially a tuft of vulval hair in the freemartin heifer and the prominent clitoris, especially in bovine the clitoris is buried in nature, so it is not well developed as compared to other animals.

For example, if you take Mare, the clitoris is very well developed, but in the case of cattle and buffalo, the clitoris is poorly developed and buried in nature in the ventral commissure of the vulva, but in the case of freemartin heifer the clitoris is very well developed and very prominent and in the ventral commissure of the vulva, there are so much of hairs that is a tuft of vulval hair characteristic symptoms in freemartin female heifer.

So, in the dissociation section so you can see the vestiges of the female reproductive tract also and being very very small pea size to ovaries in the reproductive tract and so it is underdeveloped one and only a band of tissue is available instead of fully developed cervix and the uterus and subsequently the uterine horn.

So, Diagnosis: most accurate method of diagnosis is a demonstration of sex chromosome chimerism in cultured lymphocytes, you have to collect the blood cells and you have to culture the lymphocytes and you have to identify the sex chromosomes. So, there will be a mixture of both male and female cells so that itself indicates the sex chromosomes chimerism, so these indicate, or this confirm the freemartin cases.

So unfortunately, the distribution of male cell percentage in freemartin appears to be random also sometimes. Thus, animals with low male percentages in the blood are as common as those with high male percentages. Diagnosis by a polymerase chain reaction (PCR) for the presence of the Y chromosome in the blood cells is a confirmative diagnosis. Confirmation of freemartin also and you can go for the culture of lymphocytes by identifying these X chromosomes and further you can use the PCR test for the confirmation of the freemartin also.

So, these are some of the diagnostic methods for the identification of the freemartin heifers. The next one is Intersexes or Hermaphrodites: So, Intersexes or Hermaphrodites occur most commonly in goats and pigs and less commonly in horses and dogs. It is occasionally present in sheep and cattle and is rare in the cat.

So, Intersexes are individuals in which the diagnosis of sex is confused because of congenital anatomical variations and abnormalities of the genital organs. Conditions in Intersexes include hermaphroditism, abnormalities of the accessory genital organs, gonadal dysgenesis, and freemartinism. Other forms of intersexuality are pseudohermaphroditism have been also reported, in rare cases, the XY sex reversal and true hermaphroditism were also reported. Intersexes or Hermaphrodites are commonly observed in naturally polled goats also. These intersexes are genetic females and although the polled condition is dominant the Hermaphroditic defect is recessive, sex-limited, and incompletely penetrant. Most of the Hermaphrodites are phenotypic females most with their ovotestes and may exhibit a projecting vulva and enlarged clitoris. Both ovary cells and as well as the testes the male cells, both cells are present, so it typically exhibits intersexuality.

The more the affected animal source masculine phenotypes in parents and also penile-like clitoris, hypospadias, and hypoplastic testes often in the inguinal region. Probably it may be retained, and it may not be a descendant one. Variable development or lack of development of the mesonephric and paramesonephric ducts are seen at the time of autopsy. The vagina in these Hermaphrodites is very hypoplastic and a small glass rod will only penetrate about an inch past the vulva.

So, the summary of these day 4 lectures, we have discussed:

Freemartinism, Theories of freemartins, Clinical Signs and how it will be Diagnosed and confirmed, and Intersexes or Hermaphrodites.

So, thank you very much!