(1) Nutritional characteristics of green feed
①Rich crude protein content, high digestibility, excellent quality and high biological value. The crude protein content generally accounts for 10% to 20% of dry matter. It is characterized by more content in leaves than in straw, more legumes than grasses, and high crude protein digestibility. For example, the crude protein digestibility of alfalfa is as high as 76%, while the crude protein digestibility of wild grass and mountain grass is only 51%. The protein in green feed has better quality, more comprehensive essential amino acids, more lysine and histidine and less methionine, which has a good effect on the growth, reproduction and lactation of beef cattle. Because green feed contains more comprehensive amino acids, the biological value of protein is higher, up to 80%, while ordinary seed feed only has 50% to 60%.
②Rich in vitamins. Carotene content is one of the important factors that determine the nutritional value of feed. Green feed contains a large amount of carotene, 50 to 80 mg per kilogram, which is higher than other types of feed. The content of carotene and B vitamins in leguminous grasses is higher than that of grasses in the family Gramineae; the vitamin content of green grasses is higher than that of autumn grasses. In addition, green feed is also rich in B vitamins such as thiamine, riboflavin, and niacin, as well as large amounts of vitamin E, vitamin C, and vitamin K.
③The calcium and phosphorus contents vary greatly. On a dry matter basis, the calcium content in green feed is 0.2% to 2.0%, and the phosphorus content is 0.2% to 5%. Calcium and phosphorus in green fodder are mostly concentrated in the leaves, and their percentages in dry matter decrease with the maturity of the plant.
④The nitrogen-free extract content is more and the crude fiber content is less. The crude fiber content of grass accounts for about 30% of the dry matter, and the nitrogen-free extract content accounts for 40% to 50%. The organic matter digestibility of high-quality forage is 75% to 85%. Green feed contains less crude fiber and can stimulate the secretion of digestive glands of beef cattle. Therefore, it has good palatability and high digestibility, and can be regarded as a health feed for beef cattle.
(2) Utilization of green feed
Green feed is a good feed for beef cattle, but poor control of the harvest period will also affect its quality. If harvested too early, the feed will be young and tender, with high moisture content, low yield, and poor quality; if harvested too late, the crude fiber content will be high and the digestibility will decrease. Therefore, it should be harvested at the right time, and it should be combined with seed feed and mineral feed when feeding.