How do cows fart?

Answer 1

It's called "bowel movement". Nerves in the rectum and anus send messages to the cow's brain that the rectum is full and feces need to be expelled. Nerve impulses are then sent back to the rectum, anus and lower abdominal muscles to begin the waste-expelling-process. Smooth muscle contractions in the rectum push the feces to the anus in a similar matter that food is pushed down by the esophagus into the stomach chamber. The muscles in the anus relax, and the smooth muscle contractions as well as the abdominal muscles stimulate excretion of the feces. This continues until all fecal matter that has "lined up" to be excreted are expelled. All animals have this ability, including us humans. If the nerves that are responsible for excretion of wastes (or rather, control of impulses to defecate or urinate) are damaged, the cow will have to be put down. For pets, manual stimulation must be done every so often so that the animal can defecate or urinate. Often nerves cannot be repaired, and owners feel the better alternative is to put them down.

Answer 2

Gases in the colon are released by smooth muscle contractions that send these pockets of air to the rectum then to the anus. The way these air bubbles (which can be quite smelly depending on the amount of methane that is stored up in the bubbles) are released depends on how much gas there really is in the anus. It can be a noisy release of gas, or explosive, or quiet yet really stinky. Either way you don't want to be on the wrong end when a cow has to release her flatulence.

Answer 3

They raise their tailes and let it out. They don't sit.

Answer 4

Out their vulva. They kinda squat a little on their rear legs and pee out of their vulva.