Glossary
A period where the female is not cycling, that is, she is failing to ovulate and have a normal oestrous cycle. During this period, females will not demonstrate behavioural signs of oestrus or ‘heat’.
The process by which semen is deposited into the body of the uterus of the female, usually just prior to ovulation.
A heat detection and AI method. Females that are observed in standing heat in the morning, are then inseminated in the afternoon. Where possible try to AI, 12 hrs after first onset of heat.
A subspecies of cattle breeds that are of Indian or Zebu origin. Cattle belonging to this subspecies are generally humped and originate from tropical origins (i.e. Brahman).
A subspecies of cattle breeds, for both beef and dairy purposes, that are mostly but exclusively from British or European origin (i.e. Angus, Holstein Friesian, Limousine and Charolais).
The embryo in the uterus once it has started to develop and elongate. Refers to the early stages of pregnancy.
An endocrine gland that is yellow in appearance that forms on the ovary subsequent to the ovulated follicle. The CL is comprised on luteal cells that produce progesterone whilst it is functional. The presence of a CL indicates that the female has ovulated and as such is cycling. Per ultrasound the CL appears more echogenic (lighter) and uniform than the ovary itself.
A spherical structure on the ovary that encloses the oocyte. There are a variety of types of follicles: Primordial, the primitive stage; Primary, where cell development around the oocyte has commenced; Antral, where the follicle contains a cavity filled with follicular fluid or Atretic; where the follicle regresses rather than ovulates.
FSH promotes the follicular development and initiation of the follicular wave in the female. In the male, FSH stimulates Sertoli cells involved in spermatogenesis. Secreted by the anterior pituitary. Pharmaceutical preparations of porcine FSH (pFSH) are frequently used to stimulate follicular growth for superovulation purposes.
Artificial insemination that occurs at a pre-determined time that is dictated by a series of treatments given to the female. In FTAI, there is no requirement to detect the oestrus of the females.
The process by which recipient females are treated with a series of treatments, so that ovulation will occur in a synchronised matter at a pre-determined time. This process does not require any oestrus or heat detection to occur. The ET technician will then be able to assess at the time of transfer whether a female has responded to treatment, and transfer the embryos accordingly.
A mature male (sperm) or female (oocyte) germ cell that is able to fertilise with the opposed sex to form the zygote.
A pre-ovulatory follicle that is dominant.
Produced by the hypothalamus, stimulating the pituitary to release gonadotrophins such as FSH and LH. Pharmaceutical preparations are synthetic analogues of GnRH that tend to cause an LH-like response (inducing ovulation in mature follicles), particularly when used in synchronisation protocols in cattle.
Region of the brain that is responsible for the production of GnRH. The hypothalamus responds to feedback provided by the hormone secretions associated with the ovarian and testicular structures, known as the hypothalamic-pituitary-gonadal axis. The hypothalamus acts as the control centre for the oestrous and spermatogenesis cycles.
Acronym for in vitro fertilisation. An assisted reproductive technology, where an immature oocyte is aspirated from the ovary of the female, matured (IVM) and fertilised in the laboratory and grown through to a morulae or early blastocyst stage prior to being transferred into a pre-synchronised recipient female. Precisely, IVF is also referred to as the fertilisation stage of the laboratory process, however, the term is commonly used to refer to the entire assisted reproduction process.
The process by which the uterus attempts to return to its non-gravid size and function after parturition.
LH is a hormone produced by the pituitary that is responsible for causing ovulation when the circulating concentrations peak. Basal fluctuations of LH, along with FSH, support development of the growing follicle. In the male, LH stimulate Leydig cells to produce testosterone.
Also known as luteal regression. This involves the structural and functional degradation of the CL. Luteolysis occurs in response to prostaglandin F2α (PGF2α) which is secreted from the uterus.
An acronym for multiple ovulation and embryo transfer (MOET). This refers to the assisted reproduction technique commonly referred to as simply embryo transfer (ET). MOET refers to the entire process involving superovulation, flushing of embryos and transfer of embryos into the recipient females.
A female that has given birth more than once.
A female that has not born offspring, for example, a maiden heifer or maiden ewe.
Non visible oestrus. Refers to cows that have not been observed in oestrus. This could be due to cows that are not cycling, have ovarian dysfunction, are cycling but not demonstrating behavioural oestrus, or poor heat detection practices.
Secreted by the dominant follicle on the ovary. When circulating concentrations are at the peak, oestrus behaviour results.
The reproductive cycle of mammalians. The oestrous cycle commences and ends at each ovulation and period of sexual receptivity. In cattle this period is typically occurs every 21 days, ranges between 18 and 23 days. In sheep, this period typically occurs every 17 days, but ranges between 15 and 18 days.
Sexual receptivity of the female, or when the female is demonstrating behavioural signs of ‘heat’.
An immature ‘egg’ within an ovarian follicle. The oocyte may undergo meiotic division to form an ovum (mature oocyte).
An acronym for ovum pick-up. An assisted reproduction technique that refers to the harvesting of oocytes/ova from the ovary of the animal. OPU usually forms part of the IVF process, where oocytes/Ova are aspirated from the ovary usually via a vacuum pressured needle passed transvaginally.
The female gonad, that is responsible for producing the ovum. The ovary has an important hormone function, hosting structures such as the CL and follicles that produce hormones such as oestradiol and progesterone.
A mature oocyte that has undergone meiotic division and is ready for fertilisation. A process that is usually stimulated by FSH and LH.
An endocrine gland that protrudes from the base of the hypothalamus. The function of the pituitary in reproduction is to secrete gonadotropins such as FSH and LH, in response to GnRH production by the hypothalamus.
A female that is bearing young for the first time.
A hormone produced by the CL that has various functions. During the oestrous cycle, P4 suppresses LH release thereby preventing ovulation. During gestation, P4 has a key role in maintaining pregnancy.
Hormone produced by the uterus. The primary function of PGF2α is to induce luteolysis causing regression of the CL. PGF2α is also known to cause smooth muscle contractions. Pharmaceutical preparations of PGF2α such as cloprostenol and dinoprost, are used in synchronisation programs to induce luteolysis.
An assisted reproduction technique whereby females are treated with gonadotropins (or superstimulated) to promote multiple ovulations. Phamaceutical preparations of porcine FSH (pFSH) are generally used in livestock for superovulation.
A cell that forms after the fertilisation of the male and female gametes.