1. Soybean meal is a by-product of soybean oil extraction, which is generally in the form of irregular fragments, light yellow or light brown in color, and has the smell of roasted soybeans. According to the different extraction methods, it can be divided into two kinds: one-soaking soybean meal and two-soaking soybean meal. Soaked soybean meal refers to the by-product after extracting soybean oil by leaching method; Dipping soybean meal refers to the by-product after squeezing and soaking to extract oil. One-dip soybean meal has advanced production technology and high protein content, which is the main variety circulating in the domestic spot market at present.

2. Rapeseed meal is the product of rapeseed oil extraction. Rapeseed cake is obtained after oil extraction by pressing, and rapeseed meal is obtained after leaching or pre-pressing.

3. Cottonseed meal is a red or yellow granular substance obtained by squeezing cottonseed to get oil and separating residual oil from it through leaching process.

Second, the physical composition.

1. Soybean meal is a high protein raw material and can be used as feed without detoxification. The content of protein is 40%-48%, lysine is 2.5%-3.0%, tryptophan is 0.6%-0.7%, and methionine is 0.5%-0.7%.

2. The crude protein content of rapeseed meal is between 34% and 38%, which is characterized by high methionine content (second only to sesame cake and rapeseed meal) and high lysine content. The content of arginine is low, which is the lowest in the cake feed. The effective energy value of rapeseed meal is low (low starch content makes it difficult to digest and utilize rapeseed shells). Among minerals, the contents of calcium and phosphorus are high, and the contents of selenium and manganese are also high. In particular, the content of selenium is the highest in common plant feeds.

3. The protein content of cotton meal is 44.32%, which is second only to the protein content of soybean meal (48%) and higher than the protein content of rapeseed meal (36.04%). The content of arginine is as high as 3.6%-3.8%, while the content of lysine is only 1.3%- 1.5%, which is only half of that of soybean meal.