Length of estrous cycle and time of ovulation
Length of estrous cycle, Duration of estrus and time of ovulation in domestic animals is given below-
| Species | Length of estrous cycle (days) | Duration of estrus (hour) | Time of ovulation |
| Ewe | 16-17 | 24-36 | 30-36 h from beginning of estrus |
| Doe | 20-21 | 20-35 | 30-36 h from beginning of estrus |
| Sow | 19-21 | 48-72 | 35-45h from beginning of estrus |
| Cow | 21-22 | 18-19 | 10-12h after end of estrus |
| Mare | 19-25 (21) | 4-8days | 1-2 day before end of estrus |
| Bitch | In estrus at 7-8 intervals | 7-9 days | 1st or 2nd day of estrus |
| Queen | 16 (non bred) (pseudopregnancy 36 | 5-6 days | Induced – 24-32h after mating |
Length of estrous cycle is 7-8 days, Duration of estrus is 7-9 days and Time of ovulation is 1st or 2nd day of estrus in female dog.