A variety of hormones are used within the dairy industry to treat reproductive disorders and to regulate the oestrous cycle for timed breeding. These hormones act directly on either the reproductive organs or on the pituitary gland itself to stimulate the release of naturally occurring hormones. These hormones then stimulate the reproductive organs. Prostaglandin, oestrogen and oxytocin act directly on the reproductive organs whereas gonadotrophic releasing hormone (GnRH) acts at the level of the pituitary gland.
Fertilisation is an internal process in mammals, the gamete cells however are not fully mature when they leave the gonad (either testicle or ovary) and so continue a process of maturation right up to actual fertilisation, the ovum matures fully when it undergoes its second meiotic division, the process for sperm is as follows:
Oogenesis is the female version of gametogenesis and is therefore the female equivalent of spermatogenesis. This process follows the immature, primordial ova right through to its maturation as a fertile ovum (egg).
Two processes which are important in cell division and therefore the creation of gametes (gametogenesis) are meiosis and [...]
Luteolysis is the degradation of the corpus luteum (as opposed to luteinisation – the formation of the corpus luteum). Luteolysis occurs in the absence of pregnancy, at the end of the luteal phase. The process of luteolysis is initiated by oxytocin (secreted by the corpus luteum) and prostaglandin F2a in domestic animals.
Spermatogenesis is the biological process whereby spermatogonia (the germ cell) develop into spermatozoa (the mature sperm cells). This process takes place in the seminiferous tubules of the testes; this is the starting point for spermatogenesis. Stem cells adjacent to the inner tubule wall divide, beginning at the walls and proceeding into the innermost part, [...]
Cryptorchidism is a disorder where either one or both testes fail to descend and are therefore absent from the scrotum. This usually occurs during foetal development when the testes begin their movement or descent from an abdominal position through the inguinal canal into the scrotum. Because the testes have failed to descend and therefore [...]
The oestrous cycle is the reproductive cycle found in most mammalian placental females whereby there are recurring periods when the female is fertile and sexually receptive (oestrus) interrupted by periods in which the female is not fertile and sexually receptive (anoestrus). Animals that have oestrous cycles reabsorb the endometrium (inner membrane of the mammalian uterus) if conception does not occur during that cycle. Read more…
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