Cows themselves ride each other if one or the other is in heat. However technically this is not mating, even though to the untrained dirty-minded individual it would seem otherwise. Cows ride each other if a bull or two are not present. Often the cow or heifer that is going out or coming into standing heat will ride other heifers or cows. However, if the heifer or cow is in standing heat then she will let other cows or heifers mount her without trying to move away. They rear up on their back legs (using their front legs to power themselves up, much like horses do) and settle their chest and shoulders onto the hindquarters of the female, so that their navel is in-line with the female's vulva. The back legs don't leave the ground, only their front legs do, since the back legs need to provide the mounting cow balance as she mounts and rides the female in estrus. The forelegs rest on the sides of the female directly above her flanks (often right before the hips), with the brisket resting on the tail-head and last couple vertebrae of her spine. The cow isn't putting all her weight on the hindquarters of the female being ridden, but enough so that she can rest her upper body on the female's hind quarters and, at the same time, take two thirds of her weight on her hind legs.

Cows need bulls in order to be "serviced" properly. Bulls do a bit of foreplay first to see if the cow is in standing heat. This involves staying with the cow, licking and nuzzling her perineal region (clitoral and anal area), testing to see if she will let him ride her by resting his chin on her rump and jumping up on her, and doing the flehmen response when she urinates. The flehmen response is when the bull "drinks" her pee, then lifts his head up and curls back his upper lip to let some of the urine drain into a special cavity designed to test pheromone activity. If she is ready, she will stand for him in a stance that is only subtle to humans, but obvious to the opposite sex of her species.

A bull's penis is not like a human penis where it remains outside of the body and increases in length and size by blood engorging it. A bull's penis can be retracted inside his body by a special piece of anatomy called the sigmoid flexture which forms an S-shape along the shaft of the penis. The SF allows the penis to be retracted within the sheath to inside the body, until erection occurs. Muscles known as the rectractor penis muscles keep the sigmoid flexture in place; they relax when the bull has an erection to service a cow or heifer. Erection in the bull involves the penis stiffening without any change in diameter.

When mating occurs, the bull rides the cow in the manner described above (with the forelegs acting as a clasp on the cow's pelvis), and the erect penis is thrust into the cow's vagina. The must hold her back rigid to allow successful penetration. Copulation lasts for only 1 to 3 seconds where the semen is deposited into the fornix vagina (just before entering the cervix). The bull usually only thrusts himself into her once or twice, often leaping up with his back feet leaving the ground for a fraction of a second. A bull can have an average of 20 ejaculations before satiation, but he can also achieve 60 to 80 before exhaustion takes over. (One ejaculation yields 4 to 7 ml of semen, with 6 to 10 million sperm cells in each unit of seminal fluid.) The bull then dismounts and the cow is often seen with her tail held out straight with her back arched, sometimes with a little urine or excess seminal fluids being excreted, right after copulation. The reason she does this is because of the irritation she feels in her vagina after the bull's penis has been thrust in like it has. This post-copulatory behaviour only lasts for several minutes before she goes back to her normal way of life. However, a cow's tail will often stay out and a little crooked for 24 to 48 hours after copulation. This is a good sign to go by if you haven't seen the the cow getting bred by the bull. And as for the bull, he goes in search for another cow or heifer that is in need of his services. Odd times the bull will stay with the same cow, but usually when that cow is serviced, she is not in need of him anymore.

When one of the sperm cells unites with the egg in the follicular tube of the cow, the egg them becomes a zygote which divides through cell division (mitosis) to create a blastocyst. Inside the blastocyst is the embryo, which is released into the uterus as the blastocyst ruptures. The embryo continues cell division, forming layers which predetermine the shape of the fetal calf's body parts and sex; also from the cell division, when the embryo attaches itself to the uterine wall, a placenta develops to continue to carry nutrients from the cow to the embryo-turned-fetus. The fetus continues to grow inside the womb, for an average total of 285 days from the point of conception. At the mark of 285 days (more or less, depending on the breed of the dam and sire and health and condition of the cow), a brand new baby calf is born into the world.