Approximate Gestation Periods
Domestic Animals | Days |
|---|---|
Cat | 65 |
Cattlea | |
Angus | 281 |
Ayrshire | 279 |
Brahman | 292 |
Brown Swiss | 290 |
Charolais | 289 |
Guernsey | 283 |
Hereford | 285 |
Holstein | 279 |
Jersey | 279 |
Limousin | 289 |
Shorthorn | 282 |
Simmental | 289 |
Dog | 62–64b |
Donkey | 365 |
Goat | 150 |
Horsec | 335–342 |
Llama, Alpacac | 335–365 |
Pig | 114 |
Rabbit | 31 |
Sheep | 150 |
Wild Animals | Days |
Bear (Black) | 210 |
Bison | 280 |
Camel | 365-400 |
Chimpanzee | 236 |
Coyote | 63 |
Deer (Mule and White-tailed) | 200 |
Elephant | 660 |
Elk, Wapiti | 255 |
Giraffe | 425 |
Gorilla | 270 |
Hare | 36 |
Hippopotamus | 240 |
Leopard | 95 |
Lion | 108 |
Marmoset | 150 |
Monkey (Macaque) | 180 |
Moose | 235 |
Muskox | 255 |
Muskrat | 29 |
Nutria, Coypu | 130 |
Opossum | 12 |
Otter | 270–300d |
Panther | 90 |
Porcupine | 210 |
Pronghorn | 250 |
Raccoon | 63 |
Reindeer | 225 |
Rhinoceros (African) | 480 |
Seal | 330 |
Shrew | 20 |
Skunk | 63 |
Squirrel (Gray) | 40 |
Tapir | 390 |
Tiger | 103 |
Walrus | 450 |
Whale | 450 |
Woodchuck | 31 |
Wolf | 63 |
Farmed Fur Animals | Days |
Chinchilla | 111 |
Ferret | 42 |
Fox | 52 |
Mink | |
European | 41 |
American | 40–75 |
See also page Select Physiologic Data of Laboratory Animals a. | |
a Individuals may range ±7–10 days from these averages. | |
b Gestation period is 58–72 days from breeding at unknown stage of estrus; from day of ovulation (which can be determined by progesterone or LH monitoring), gestation period is 62–64 days. | |
c Individuals may range 20 days from these averages. | |
d 180+ days due to delayed implantation | |
Approximate Incubation Periods
Domestic Birds | Days |
|---|---|
Chicken | 21 |
Duck | 28 |
Muscovy duck | 35 |
Goose | 28 |
Guinea fowl | 28 |
Turkey | 28 |
Caged and Game Birds | Days |
Budgerigar | 18 |
Finch | 14 |
Parrot | 26 |
Pheasant | 24 |
Pigeon | 18 |
Quail | 16 |
Swan | 35 |
Features of the Reproductive Cycle
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. |
The reproductive system provides the mechanism for the recombination of genetic material that allows for change and adaptation. Manipulation of this system in breeding management programs allows the rapid and dramatic alteration of the conformation and productivity of domestic animals. Theriogenology is the veterinary clinical specialty that deals with reproduction.
The reproductive system is incredibly complex in both its anatomy and physiology, and all aspects must be considered when resolving reproductive problems. The differences in the reproductive system between the sexes and among species are extensive. Both sexes have primary sex organs and primary regulatory centers. Gonads and function-adapted, tubular genital organs constitute primary sex organs in both sexes. The pituitary gland and the hypothalamus are the primary regulatory centers; thus, the regulatory function is, in part, neuroendocrine in nature. In pregnant females, the fetoplacental unit has a significant role in maintaining and terminating pregnancy.
For the temporal and physiologic features of the reproductive cycles of selected species, and see Table: Approximate Incubation Periods and see Table: Features of the Reproductive Cycle.
