(a) Ovulation : This is the rupturing of the ovary wall to release mature eggs (ova) or ovum into the oviduct of the female animal. It is under the control of the pituitary gland and it occurs in between oestrus cycle.
(b) Oestrus cycle : This is the interval from the end of one heat period to the beginning of another. It is the period of heat in farm animals and it is controlled by a hormone. It varies from one animal to another, e.g. Cow = 20 - 21 days; Ewe = 7 -21 days; Sow --- 14 - 28 days .
(c) Gestation:This is the time between conception and birth, during which the embryo or fetus is developing in the uterus
(d) Parturition : This is the act of giving birth in farm animals. It marks the end of pregnancy and the beginning of lactation. The act of giving birth in Cow - Calving, Sow - Farrowing, Ewe - Lambing, Doe (Goat) Kidding.