Напишите по-английски краткий пересказ данного текста. SHEEP BREEDING
Various systems have been developed in sheep production. In some regions large flocks are grazed on the open range under the control of shepherds. The flocks may be moved from place to place to take advantage of cheap feeds and natural forage.
Range sheep are normally white-faced crosses carrying both long-wool and Rambouillet breeding, thus they are very hardy and thrifty. In winter period they are kept in flock, of from 1.000 to 4.000 head at lower altitudes, and are moved in bands ranging from 1.000 to 1.500 head to summer range at much higher altitude, sometimes 480 kilometers from their winter shelter.
The female bears up to three young after a gestation period of about 150 days. The breeding ewes are mated to rams and produce lambs during the late winter or early spring so that the lambs will be old enough to move to summer grazing without difficulty. The average number of lambs raised per hundred ewes is 91, though some breeds are noted for producing a high percentage of twins, and others, such as the Dorset, for both high frequency of twins and heavy milk production.
Lambs are usually delivered in the spring and are sold at ages of from three to eight month and weights of around 18 kg for Easter lambs, and 45 kg for the usual market lambs. If abundant forage is available, the lambs may be marketed directly after weaning. In case the lambs have not reached marketable condition, they may be moved to feedlots and given additional food before they are sold.
Commercial sheep farming is usually conducted on large areas of land, divided into operational units containing 1.000 or more animals per unit. Large flocks are maintained partly for wool and partly for market lambs. Sheep are sheared in the spring after the worst winter weather has passed and the average fleece weight per shearing is 3.78 kg.
Perhaps the first sheep people domesticated descended primarily from the mouflon in southwestern Asia about 11.000 years ago. At present some wild species can be found in different areas of the world such as the Dall`s sheep in Alaska, the mouflon in Mediterranean countries, the urial in Afghanistan, the argali in eastern Asia etc.
