What do cows originate from

When an animal chews its cud it is a sign of health and contentment. Other ruminant animals include deer, elk, sheep, and goats. Life Cycle. Many ranchers run cow-calf operations. They keep a herd of cows to produce calves. The cows are bred to calve in the spring or fall. Cows, like humans, are pregnant for nine months. Colostrum, a cow's first milk after birth, is very important to a newborn and should be consumed as soon as possible.

Calves are born with no protection from diseases, so their antibodies come from their mother's milk. Calves absorb antibodies from the colostrum directly into their bloodstream through pores in their intestinal lining.

Within the first few hours the intestinal walls begin to thicken and the pores close up. By the time they are six hours old they can only absorb a fraction of what they need. After filling their stomachs calves may feel like bucking and playing. For the first three weeks of the calf's life they only drink their mother's milk, because their rumen is not yet fully developed.

Rumen is one of the stomach chambers in ruminant animals. Humans do not have rumens. Between weeks the calf goes through a transitional period where they start eating some hay and grass along with the milk. After eight weeks the calf's rumen should be fully functioning. The rumen will grow 25 times larger from birth to adulthood.

A newborn calve is commonly tagged. Each ear tag has an individual number which helps ranchers pair the mother with their young and track the calf through its lifecycle. Within the first few months, the calves will be branded. A brand is an identification mark for cattle. It can either be a hot iron brand or a freeze brand. Some operations use earmarks, as an additional way to identify their cattle. During branding all calves are vaccinated to help prevent disease. The young male calves are castrated during the first few months.

After castration, they are referred to as steers. Calves are usually sold after they are weaned, at about six-eight months.

After weaning, cattle are sent to feedlots for approximately days where they are fed a high-energy ration of grain and hay. After this time called finishing, the cattle are sent to a harvest plant. To keep the herd size approximately the same, ranchers save replacement heifers females.

The steers males will be sent to the feedlot while a few heifers are kept behind to raise and later produce calves themselves. Other heifers will go to the feedlot as well. Steers are more common in the beef industry, because they grow faster and naturally have more muscle.

The ideal breeding age for heifers is at least months of age, depending on breed. There are numerous breeds of cattle raised in the United States. Some breeds have been around for centuries, while others have been developed in the last couple of decades by mixing older breeds. Each breed is characterized by different traits suchs as size, weather tolerance, color, markings, hair length, and temperament.

There are two classifications; Bos indicus and Bos taurus. Bos taurus includes British and Continental. Paleolithic people probably captured young aurochs and selected for the most docile of the creatures.

The "fierce and scary" creatures gradually became tamer, domesticated animals, McTavish said. Wild aurochs survived until , when hunting and habitat loss drove the creatures to extinction. On Columbus' second trip to the Americas in , he brought cattle. To untangle the history of these New World breeds, McTavish and her colleagues analyzed the genetic lineage of three cattle descended from the New World cows: Texas longhorn, Mexican Corriente and Romosinuano cattle from Colombia, and compared them with 55 other cattle breeds.

The researchers found that the New World cows evolved from both Indian and European lineages. In addition, historical records suggest that Longhorns underwent natural selection while they were living in semiwild herds for years, or about 80 to generations. Dr Jean-Denis Vigne, a CNRS bio-archaeologist and author on the study, said: "In this study genetic analysis allowed us to answer questions that - until now -archaeologists would not even attempt to address.

This restricted area could be explained by the fact that cattle breeding, contrary to, for example, goat herding, would have been very difficult for mobile societies, and that only some of them were actually sedentary at that time in the Near East. Dr Marjan Mashkour, a CNRS Archaeologist working in the Middle East added "This study highlights how important it can be to consider archaeological remains from less well-studied regions, such as Iran. Without our Iranian data it would have been very difficult to draw our conclusions, even though they concern cattle at a global scale.

Image: Blond d'Aquitaine on a mountain pasture. Source: Wikimedia. Media contact: Clare Ryan.