Today's cattle are predominantly of two species; Bos taurus or Bos indicus. Both of these species are descendants from the wild Giant Ox (aurochs, of the species Bos primigenus). The Aurochs were a widespread species, but the last one was killed in 1627 in Poland (Clutton-Brock 1989a). The numerous breeds seen today have been developed from the B. taurus or B. indicus as farmers selected animals with certain traits for different needs. Other minor groups of cattle in South East Asia have been derived from local wild bovids. In Saskatchewan, cattle serve two main purposes; beef production or dairy production. On Saskatchewan's modern farms, animals are rarely used for power, as they are in some countries. Specialized breeds are used for each purpose in commercial, intensive farms, as well as most family farms. Breeds are specialized as the nature of energy partitioning in an excellent beef cattle is very different from that used by a prize dairy cow. There are breeds that have been developed to serve both purposes, but since beef and dairy production are mutually exclusive, the dual purpose animals are a compromise, not quite as good as either specialized breed, but able to provide for both needs in one animal. Cattle are responsible for the efficient conversion of grains unsuitable for human consumption, and forage grown on land not suited for gain and oilseed production into a high quality source of protein. Cattle, when properly managed, can make use of low quality, or non productive rangeland without causing damage to the environment. There are 4 main types of beef production: 1. Purebred Breeders operate to breed and raise registered stock for replacement of aging, or non productive stock sell purebred animals to be used in breeding programs for cross bred commercial beef producers may use advanced breeding programs incorporating embryo transfer, and artificial insemination to improve carcass traits, fertility and reproduction 2. Cow Calf Producers maintain a breeding herd, usually of crossbred animals raise young animals to weaning, at which time they are sold to stocker or feedlot operations can sell, or retain ownership of the calf through the backgrounding or finishing program may be required to raise a number of animals to be used as replacements for the breeding herd 3. Backgrounding or Stocker Operations purchase weaned calves from cow calf producers, or have raised calves which were not sold feed roughage based rations for low cost weight gain commonly use British breeds because they respond well to prolonged feeding before moving to a feedlot sell cattle to feedlot operations to be finished to the desired carcass quality 4. Feedlot Producers purchase weaned calves or backgrounded animals animals are housed in pens in large numbers feed high energy concentrate based rations to fatten cattle to produce a desirable carcass The Poundmaker feedlot operation in Saskatchewan is shown in the image.