Feed storage characteristics and storage technology

The feed industry is the basis for the rapid development of animal husbandry in China and an important way to achieve grain transformation. Since the reform and opening up, with the continuous application of new equipment, new processes and new technologies, the variety of feeds has increased, the output has become larger and larger, and the quality and safety requirements of feed have become higher and higher. In order to ensure that people can timely and adequately consume safe, high-quality, nutritious livestock and poultry products without pollution and harm, we must do everything possible to improve the quality and safety of feed. In addition to optimizing the formulation of the feed and improving the production process, the way to improve the quality and safety of the feed is to work hard on the reasonable storage of the feed. Because of the reasonable storage technology, not only can the storage time be extended, the quantity loss can be reduced, and more importantly, the feed can be prevented from being deteriorated and the nutritional function is reduced, thereby effectively improving the use value of the feed and the economic benefit of the feed enterprise.

1 Storage characteristics of feed

There are many types of feed, but from the perspective of its composition and processing, there are mainly grain and oil processing by-products and compound feed. These feeds have different storage characteristics due to different raw material compositions and physical shapes, but generally have the following characteristics.

1.1 High content of starch and protein, easy to absorb moisture and return to the tide

The starch content of rice bran is 37.5~39%, the protein content is 15~17%, and the protein content of cake is 30~50%. These ingredients have hydrophilic properties, so the feed has a strong ability to absorb moisture. On the other hand, due to the loose structure of the grain and oil by-products, the porosity is large, and the hygroscopicity is also enhanced. According to the experiment, under the same temperature and humidity conditions, the moisture absorption rate of bran is more than twice that of wheat, and the equilibrium moisture of bran is higher than other original grains. For example, in saturated state, the equilibrium moisture of the bran can reach 38-40%, while cereal cereals are generally only 20%. Although the moisture content of the cake is 5~10%, the outer layer is easy to absorb moisture and mold during storage.

Because the compound feed also contains a large amount of starch and protein, especially the animal protein ( fish meal , bone meal, meat meal, blood meal, silkworm cocoon powder, etc.) in the feed, the hygroscopicity is very strong.

1.2 Large amount of bacteria, easy to mold and deteriorate

Because the feed contains nutrients such as sugar, protein, fat, etc., and is pulverized and steamed during processing, the nutrients are exposed, and the moisture content is high. Therefore, the feed is easy to breed microorganisms, especially suitable for mold reproduction. . As a result of the large-scale reproduction of mold, not only will the nutrient material be seriously lost and deteriorated, but also the poisoning of the feed under the infestation of certain toxin-producing microorganisms, thereby endangering the health of people and animals.

1.3 high fat content, easy to oxidize rancidity

The fat content of grain and oil processing by-products is relatively high, such as rice bran fat content is generally 17 to 18%, and new rice bran is even as high as 22%. Rice bran fat contains a considerable amount of lipolytic enzymes. Under the action of lipolytic enzymes, the fat in rice bran is easily decomposed, resulting in a large increase in free fatty acids. According to the experiment, the temperature of the rice bran just out of the machine is above 30 °C, the acid value is below 10, after 5 days, the acid value rises to above 15; after 10 days, the acid value rises to above 25; after 20 days, it rises to above 35. In summer, the acid price rises the fastest, and it takes only a few days to get to 80. At the same time, the rice bran temperature also rises, and the red knot is fast. After the fat is decomposed, the acid value increases and the quality deteriorates.

2 Common feed storage technology

2.1 Storage of grain and oil processing by-products

The new rice bran should be cooled and cooled, and then the grain temperature will be lowered before entering the warehouse. For short-term storage, the moisture should be controlled within 15%, and the long storage should be within 13% for safe storage. Pay special attention to the inspection of insects and fever during storage. Pay attention to whether there are agglomeration, insects and fever in the middle and lower layers of the stack. At the same time, in the hot season, the layer should be deepened to prevent condensation and mildew. Rice bran should not be stored for a long time, and the storage time should not exceed 10 days. Rice bran in the hot season should be supplied with the machine. If rice bran must be stored due to special circumstances, the lipase activity should be pre-damaged to control the increase in acidity. For example, the newly-launched rice bran is baked and heated in 2~4 hours for 10~15 minutes, so that the temperature reaches 95°C or above, and the water content is reduced to 4~6%, which may be stored for a long time; the heating temperature reaches 115~126°C. The rice bran with water content reduced to 3~4% can be stored for about half a month. When the rice bran is put into the warehouse, the pile should be loose, the height should not exceed 1.33 meters, and the stacking height automatically transported into the warehouse by the conveyor should not exceed 2 meters. When stacking, you can't step on the surface with your feet. Because the heat accumulated in the stack is not easy to dissipate after the actual operation, it will accelerate the decomposition and deterioration of the fat. After the rice bran is put into the warehouse, it should be inspected frequently, diligently turned over, and pay attention to check the temperature, color and smell of the pile. If there is heat or agglomeration, it should be piled up, spread, ventilated and arranged early.

Generally, the new bran moisture is not high (about 13%), but the temperature is very high. Although it is about 30 °C in the low temperature season, the temperature should first be lowered to below 10~15 °C, and then unpacked in bulk. Storage. In the winter, continue to use the method of digging the dome to prevent condensation and mildew. Immediately after the warm spring, the gland is tightly closed to prevent intrusion of external heat. During the storage period, you should also diligently check the diligence. If you find fever and mildew and agglomeration, you need to deal with it quickly. In the hot season, heat dissipation and dehumidification should be strengthened, and the stack height should not exceed 5 packs.

2.2 Storage of compound feed

More than 70% of the compound feed is corn or barley, wheat and other grain-based energy substances. After these materials are crushed, the molds are easily multiplied in them, which makes the feeds deteriorate and even cause poisoning of livestock. Commonly used rice bran, fish meal , cake, meat and bone meal, silkworm cocoon powder and other raw materials have high fat content, improper storage, easy to cause rancidity. Adding vitamins, etc., is also very easy to oxidize and degrade, reducing the value of feeding. Therefore, the processed compound feed must be properly stored. The compound feed should be stored in a place that is low temperature, dry, protected from light and clean during storage. The new storage time should be decided according to the validity period specified in the feed product specification. The storage period of the compounded granular feed is generally from January to March; the storage period of the powdered compound feed should not exceed 10 days; the concentrated powdered feed is generally added with an appropriate amount of antioxidants, and the storage period is 3 to 4 weeks; the additive premixed feed After the addition of antioxidants, the storage period can reach 3 to 6 months.