Ovulation: ovulation refers to the rupturing of the grafian follicle in order to release mature eggs (or ova). It is under the control of pituitary gland hormone. It occurs when female animals are not on heat.

Oestrus cycle: this is the period when the female animal is on heat. It is also the interval from the end of one heat period to the beginning of another. E.g                                                                   
sow —- 14-28 days
ewe — –  17-21 days
cow — –  20-21 days
doe (goat)-17-21 days
Gestation: this is the period of pregnancy in female animals. It represents the period between fertilization of an ovum to birth of the young animal. During this period, animals are not on heat. E.g
cow —- 280 days
sow —- 114 days
ewe —- 145-150 days
Parturition: this is the act of giving birth in farm animals. e.g
cow —- calving
sow —- farrowing
ewe —- lambing
doe —- kidding