Hereditary Causes of Infertility
Dr. Atef Abdel-Hai Khalil Selmi
Professor of Obstetrics, Gynecology, & A.I.
Faculty of Veterinary Medicine
( 3 )
Hereditary Causes of Infertility
Freemartins are sterile heifers (90%) born co-twin
Incidence of twinning varies greatly among breeds
of cows ( 0.5-4.2% in Holstein-Friesian, 2.4-4.2% in
Simmental, and 2.5-3.2% in Charolais).
Most of twin births are dizygotic (90-99 %).
This condition is a unique form of intersexuality
characterized by abnormal developmental changes
during sexual differentiation.
Developmental abnormalities leading to
1-The sex of an individual can be determined at
three levels, genetic, gonadal, and accessory
2-Placental fusion and anastomosis takes place
at about 20 days of gestation between
chorioallantoic blood vessels of male and
female placenta alters differentiation of
female genital organs (the critical period of
sexual differentiation is between 40 and 50
days of gestation in cows) .
3-Ovarian functional alterations precede
morphological changes owing to marked
elevation of androstenedione concentration in
the serum of the female embryo as early as 40
days of gestation.
4-These initial changes are followed by elevated
concentrations of testosterone and
androstenedione in the gonads of the female
fetus by 75 days of gestation.
5-Testicular cords and cells resembling testicular
interstitial cells are then developed in the ovary
of the female fetus by 70 days of gestation.
6-Cellular exchange between male and female
fetuses results in development of chimaeras
(having XX/XY cells due to vascular
7-Developmental abnormalities and degree of
musculinization in the genital system of
freemartins varies from animal to animal. It
depend upon the developmental stage of the
conceptus at the time of anastomosis, degree
of anastomosis, amount and duration of
inhibitors interchange ( ??? ).
Symptoms and clinical findings:
1-Freemartins are phenotypically steer like in
appearance and never come in heat despite
passing age of puberty (ox horn, massive
shoulder, high limbs, narrow pelvis, small
narrow vulva, large prominent clitoris,
prominent tuft of coarse hair arises from the
ventral vulval commissure, and the udder is
underdeveloped with small rudimentary teats).
2-Clinical examination reveals that the
measurements of all reproductive organs are
markedly decreased (size and weight).
3-The length of both vagina and vulva is
markedly decreases (6-8 cm) and reveals blind
vestibule as detected by Fincher pencil test or
4-Gonads are either aplastic or hypoplastic and
detected as firm nodular structure.
5-Uterus, uterine horns, cervix, and anterior
vagina are firm and uncanalized (can be
detected as cord like structures).
6-Testicular structure and male accessory glands
(Seminal gland) can also be detected in some
Phenotypic appearance is a steer like
Application of Fincher pencil
test reveals blind vestibule
Subnormal decrease in all measurements of the genitalia
Clinical significance and economic importance:
1-Increased incidence of twinning pregnancy
increased the possibilities of freemartinism.
2-Increased incidence of freemartinism
increases the number of sterile heifers and
increases incidence of anestum in the herd
that reduces fertility of the farm.
3-Freemartin should be fattened and
4-Females giving twin births should controlled
and their offsprigs should be sexually
Hermaphrodite is a term applied to individuals
whose genital organs exhibiting both sexes.
Hermaphroditism has been recorded in all
animal species, but with high frequency in goats (6
-14.9 %) and pigs.
Hermaphroditism in goats caused by an
autosomal recessive gene linked to an autosomal
dominant gene for polledness or hornlessness.
This gene have variable penetrations, and be
responsible for sex reversal of genetic females to
phenotypic males (because all hermaphrodites are
genetically females, 60 XX kariotype) .
Classification of hermaphrodites:
They are classified according to the dominating
genital organs into:
1- True hermaphrodites ( low incidence):
A-Bilateral (4gonads, TTOO, OOTT, TOOT, OT
B-Unilateral (3 gonads, TO O, TO T).
C-Lateral (2 gonads, T O).
2-Pseudo-hermaphrodites (high incidence):
Morphological features of masculine type male
1-Pseudohermaphrodites Kids are hornless, and
develops an abnormal pouch at the terminal
part of urethra that filled with urine.
2-Such a condition suffer urine incontinence
that was treated by surgical dilatation of the
external urethral orifice.
3-External genitalia revealed absence of
scrotum, the penis is abnormally short, and
the external urethral orifice open just cranial
to the ischial arch.
Male pseudohermaphrodite kid
Morphological features of pseudohermaphrodites:
1-Older cases are hornless and exhibiting either
masculine or feminine appearance.
2-The external genitalia consists of small
subcutaneously located testes and the
scrotum is seldom developed.
3-The penis is short and exhibits no sigmoid
4-the free end of the penis is bent upwards that
makes urine stream directed upwards.