From the milk in your cereal to the hamburger you have for dinner, cows are a large part of your daily life. Cows were first domesticated more than 8,000 years ago and have been important to the human food chain ever since. Always chewing their cud, cows have unusual stomachs that help them process the grass they eat. Farmers and ranchers raise cows for dairy products, such as ice cream, cottage cheese and butter, as well as beef.
You've probably heard that cows have four stomachs, but they don't. They have one stomach just like you, but theirs is divided into four compartments --- the rumen, the reticulum, the omasum and the abomasum. Each of these compartments has a separate function.
The rumen is like a 50-gallon holding tank for partially digested feed. Cows burp up some of this glop to use as cud. The reticulum captures any foreign objects the cow might eat accidentally, such as a small bolt. The omasum is a natural filter. The abomasum does most of the food digestion, absorbing nutrients and passing along waste to the bowels.
Cows might look like they're chewing a big wad of gum, but they're really chomping on regurgitated grass. Like sheep and camels, cows are ruminants. They spit up some of the undigested food they keep in a special compartment of their stomachs and chew it for up to eight hours a day. Cows need to eat hay or long grasses to create this cud. Mixing this cud with saliva as they chew gives the cow a natural antacid to settle its stomach, according to Donna M. Amaral-Phillips at the University of Kentucky.
What Cows Eat
Historically, cows ate grass. To get enough to eat, large herds of cows travelled from place to place, grazing and keeping an eye out for wolves and other predators. Though some farmers still pasture their cows, large agricultural businesses often feed their cattle corn and other grains from troughs. The average cow eats about 18.1kg. of feed every day and drinks enough water to fill up a bathtub, according to the U.S. Department of Agriculture.
Kinds of Cows
Four popular breeds of dairy cows are the Holstein, Jersey, Guernsey and Brown Swiss. A good dairy cow can produce 25 gallons of milk daily. Before American farmers started keeping large numbers of cows on dairy farms and shipping milk to stores and processing plants, each family usually had its own cow. Often, it was the children's job to milk the cow each day. Today, most cows are milked with an automatic milking machine as they stand in their stalls.
Popular breeds of cows raised to provide hamburger, steaks and ribs are Herefords and Angus cattle. Television medical expert Dr. Oz recommends buying beef produced by grass-fed cattle, since it contains healthy fats called conjugated linoleic acids (CLAs). Corn-fed cows don't develop this healthy CLA fat.