Species | Age at Puberty | Cycle Type and Length (Range) | Duration of Estrus | Best Time to Breed | First Estrus After Parturition | Comments |
---|---|---|---|---|---|---|
Cattle | 10–12 months, usually first bred ~14-15 mo | Polyestrous all year; 21 days (18–24) | 18 hours (6–24) | Insemination from midestrus until 6 hr after end of estrus | 20–60 days | Ovulation 10–12 hours after end of estrus. |
Sheep | 6–9 months | Seasonally polyestrous, early fall to winter; 17 days (14–20) | 24–36 hours | 18–20 hr after onset of estrus | Next fall | Ovulation near end of estrus. |
Goat | 5–7 months | Seasonally polyestrous, early fall to late winter; 21 days | 24–48 hours | Daily during estrus | Next fall | Many intersexes born in hornless strains. |
Pig | 6–7 months | Polyestrous all year; 21 days (19–23) | 40–60 hours | Daily during estrus | 4–10 days after weaning | Ovulation usually ~40 hours after beginning of estrus. |
Horse | 10–24 months | Seasonally polyestrous, early spring through summer; ~21 days (19–23) | 5–7 days | Last few days of estrus, just before ovulation; should be bred at 2-day intervals | 4–14 (9) days | Ovulation usually 1–2 days before end of estrus. Double ovulation occurs in ~20% of estrous periods, but twins rarely progress to term. |
Alpaca | 12–18 months | Polyestrous all year in North America; Not applicable | Up to 36 days | When a large, viable follicle is present | Fertile within 15–20 days | Alpacas are induced ovulators. |
Dog | 6–24 months; earlier in smaller breeds, later in larger breeds | Monestrous all year; 6–7 mo | 9 days (3–21) | Second day after ovulation | 4–5 months | Proestrous bleeding 7–10 days. Ovulation usually 1–3 days after onset of estrus. Ova shed before first polar body has been extruded (primary oocyte). |
Cat | 4–12 months | Seasonally polyestrous, spring through early fall; 14–21 days | 6–7 days | Daily from day 2 of estrus | 4–6 weeks | Induced ovulation 24–48 hours after breeding. Pseudopregnancy lasts 40 days. Infertile matings delay onset of next cycle ~45 days. |