Some key definitions to know:
- Cow: mature female bovine.
- Bull: intact (often mature) male bovine.
- Steer: castrated male bovine
- Heifer: immature female bovine (often younger than 2 years of age)
- Heifers and bull calves may reach puberty before weaning age at around 6 months of age
- Sexual maturity of heifers is typically reached at 15 months of age or 65% of her mature weight, whichever comes first. Breed heifers at this time. (Note: Brahma-type heifers will reach sexual maturity several months later than Continental or British-type heifers)
- Sexual maturity of bulls (of Continental and/or British breeding) is typically at 12 to 14 months of age. Brahma-type bulls will reach sexual maturity at around 16 to 18 months of age.
- Average regular estrous period/cycle (includes time cow/heifer is in heat and not in heat according to progression and regression of the corpus luteum) is 21 days long.
- Estrus (heat period) lasts around 24 hours.
- Heifers nor cows cannot be bred to become pregnant anytime after their heat period. They must be in heat in order to conceive.
- Breeding period should be around 45 to 60 days long, 90 days if a breeding herd is slowly getting into a tighter breeding schedule.
- Cattle are not monogamous; they are polygamous. One bull can breed between 10 and 40 cows in one breeding season, depending on the bull's age, libido, and experience, and on the size of the corral or pasture which the cowherd and bull has access to. Competition between bulls for mating rights may also affect conception rates.
- Consider utilizing artificial insemination if you only have one or two cows in your herd instead of a bull.
- Signs of estrus in cows and heifers: pacing, bellering/calling, mounting/being mounted by other cows, vulva may appear swollen, mucus discharge from vulva, etc.
- Cows should not be bred until approximately 3 months post-calving to allow the uterus to shrink back to normal and allow estrous cycle to get back to normal cycling.
- Signs of a cow or heifer has been bred: Back hunched up, tail held out at a crooked angle.
- Average gestation length in cows is 285 days (9.5 months) long. Breed, nutritional plane and environmental factors will play a role in actual length of gestation.
- Rare for a cow to come in heat while pregnant. A "false heat" may occur after the first couple weeks or so of pregnancy. If subsequent heats follow, the cow/heifer is open due to reabsorption of the embryo.
- Normally a pregnant cow will show no signs of heat during the entire pregnancy period.
- Preg-checking commences 90 days post-breeding, via rectal palpation or blood sample.
- Basic signs to look for: pacing, moving away from herd to find a private spot, laying down then getting up again, tail held out, stopping activity when feeling contractions, back may be hunched up as if straining to urinate, water sac hanging, then feet.
- Feet that are appearing should be facing downward
- Birthing process usually takes an hour or two: sooner for more experienced cows.
- Always watch heifers and cows for any problems. If you find a cow or heifer that hasn't made any progress after around 20 to 30 minutes, it may be time to get her in a head-catch and see what's going on.
- Keep your vet or an experienced cattle producers' phone number on speed dial should any problems arise.