is the process whereby the follicle releases the ova into the
uterine horn. The coordination of the ovulation process with estrus
is critical for reproductive success. The control and coordination
of these events is through the endocrine system. The hypothalamus
produces GnRH, which stimulates the release of FSH (follicle
stimulating hormone). FSH induces the growth of the dominant
follicle until ovulation and also stimulates ovarian production of
estrogen or estradiol, which causes the animal to show behavioural
signs of heat and also prepares the uterus for conception. In
addition, estradiol suppresses FSH secretion and stimulates LH
secretion of the anterior pituitary. LH starts the ovulation process
and stimulates luteinization of the follicle following ovulation.
The corpus luteum (CL) is the luteinized tissue left after the
follicle ruptures; it produces predominantly progesterone.
Progesterone completes the uterine preparation for pregnancy and
feeds back to anterior pituitary, inhibiting both FSH and LH and
preventing ovulation during pregnancy. If an animal does not
conceive, then the uterus produces prostaglandin F2α (PGF2α) which
causes luteial regression at about the sixteenth day of the oestrous
cycle. If the animal stays pregnant, then eventually placental
production of progesterone takes over from luteial production to
maintain pregnancy. In cattle ovulation occurs 12-15 hours after the
onset of estrus.
Fertilization is a physiological process in which the male and
female gametes each having haploid (n) no. of chromosomes fuse to
Site of Fertilization:
Site of fertilization is lower part of ampulla of fallopian tube.
Bull ejaculate semen in vagina while in case of AI, the semen is
ejected in the body of uterus, which rush for the fertilization in
fallopian tube. After successful fertilization animal becomes