The quality and freshness of feed is directly related to the growth performance and health of animals, and also affects the input and return of farming. Poor quality or deteriorated feed will make animals eat less, lose resistance, become sick or even die more easily, and ultimately increase farming costs and reduce returns.
Feed silo design is often overlooked in feed storage, but its impact on the preservation effect of feed is much greater than the storage time and other basic factors. Steel plate silo construction cycle is short, small footprint, sealing is also easy to control, has become the main choice of feed storage, its design details are reasonable or not, directly determines the quality of feed storage period is stable or not.
Understanding the relationship between silo design and feed quality
From the storage point of view, whether the quality of feed is good or not depends on whether the nutrients can remain intact and stable, and freshness means that the feed is not rotten, moldy or oxidative deterioration. During the storage period, the core nutrients of protein, fat and vitamins will be slowly degraded by the environment, and the freshness will be reduced, which will affect the digestion and absorption of the feed by the animals.
The temperature, humidity, oxygen content and airflow of the storage environment will determine whether the nutrition of the feed can remain stable. For every 10°C rise in temperature, the rate of fat deterioration in feed will accelerate by 1.5 to 2 times, and the rate of vitamin C depletion will increase by 2 to 3 times; fat oxidation will become faster when the oxygen concentration exceeds 8%, and microorganisms will easily grow once the humidity is higher than 12%.
The silo design itself has a greater impact on feed quality and freshness than the storage time. In the same storage time, a well-designed steel silo can control the fat oxidation rate of feed within 5% and vitamin loss no more than 10%; while a silo with faulty design, even if the storage time is cut in half, the fat oxidation rate may still be more than 20%, and the vitamin loss will be more than 30%.
Core silo design factors affecting animal feed quality and freshness
All the elements of silo design are directly related to whether the feed is deteriorated and whether it can be kept fresh, among which the sealing, moisture-proof ability and unloading structure are the most critical aspects. To reduce feed oxidation, mold, caking and other problems, you have to match these design elements, but also consider the construction costs and ease of use.
The design of steel plate silos should be centered around the characteristics of feed storage, combining the actual needs of different farming scenarios and finding a balance between technical feasibility and economic cost-effectiveness. If these core designs are flawed, the risk of feed storage will rise significantly, which will ultimately lead to higher expenses in the farming chain.
Sealing and oxygen control in silo design
Oxygen accelerates feed spoilage and oxidation and also promotes mold growth. Unsaturated fatty acids in the feed will undergo oxidation when encountering oxygen, producing harmful substances and destroying the structure of vitamins; when the oxygen content exceeds 5%, mold spores will multiply rapidly and produce mycotoxins, which will have an irreversible effect on animal health.
The sealing structure of the steel plate silo directly determines the effectiveness of oxygen control. A good sealing design will generally use double sealing tape with sealant, and the sealing gaps at key locations such as the roof flange, bin door, and discharge opening should be controlled within 0.5mm, which can stabilize the oxygen concentration in the bin at less than 2%, slowing down fat oxidation and mold growth. This design can extend feed storage time by more than 30%, while reducing the likelihood of exceeding mold toxin levels.
However, high-performance seal designs can cost more to build, typically 15 to 20 percent more than regular seal designs. Additionally, sealing structures require regular maintenance, with sealing tapes being inspected for deterioration and replaced every six months. If not maintained, the sealing effect will slowly decline with the use of time, the amount of oxygen penetration increases year by year, after 3 years the oxygen concentration in the warehouse may rise to more than 4%, the seal will not play a protective role.
Moisture-proof design and condensation control
Moisture is the main cause of feed caking, microbial growth and uneven quality. When the moisture content of feed exceeds 14%, granular material will soften and clump, powder is easy to arch, while bacteria and molds will multiply, which not only reduces the nutritional value of feed, but also may produce toxic metabolites. Uneven distribution of moisture will also make the feed deteriorate at different rates in different areas of the silo, affecting the stability of the overall quality.
Condensation inside the steel plate silo is caused by the temperature difference between the inside and outside of the silo. When the temperature outside the silo is lower than the silo more than 5 ℃, the silo wall surface will produce condensation, per square meter of the silo wall every 24 hours can condense 0.3 to 0.5 liters of water, this water penetrates into the feed, will make the local moisture content significantly higher. Especially at the change of seasons, when there is a big difference in temperature between day and night, the amount of condensation produced will increase by 2 to 3 times, and the difficulty of preventing and controlling condensation will also become greater.
Reduce the silo internal moisture accumulation, the key to do a good job of silo wall insulation, ventilation system configuration and the bottom of the silo moisture these points. Silo wall with polyurethane insulation, the thickness to reach 50 to 80 mm, can control the temperature difference between inside and outside the silo within 3 ℃, reduce the generation of condensation; silo top installation of forced ventilation devices, hourly ventilation is not less than 0.5 times the capacity of the silo, can be discharged in a timely manner in the silo of moisture, so that the relative humidity stabilized at 65% or less; the bottom of the silo paved with a moisture-proof membrane, but also to do the 3 ‰ to 5 ‰ of the slope of the drainage, to prevent the ground from moisture infiltration into the Feed.
Again, these moisture control designs are a trade-off between cost and effectiveness. Insulation and forced ventilation systems can add 20 to 25 percent to construction costs, and the ventilation system requires electricity to operate, adding $3 to $5 per cubic meter of silo capacity to the annual electricity bill. If the thickness of the insulation layer is reduced or the frequency of ventilation is lowered, although the construction and operating costs can be reduced, condensation control will become less effective, the risk of feed caking and mold rises, and the feed loss rate may be increased by more than 5%.
Unloading structure and first-in-first-out (FIFO) performance
The unloading structure of the silo determines how the feed flows in the silo, which in turn affects the feed retention time. The longer the feed sits in the silo, the higher the risk of oxidation and mold, so it is important to achieve FIFO to ensure that the feed is fresh. The state of feed flow varies greatly between different discharge structures, and the impact on freshness is also different.
Overall flow unloading structure through the optimization of the silo cone angle and the smoothness of the inner wall, so that the silo feed overall downward flow, there is no stagnant area, the difference in feed retention time can be controlled within 24 hours, to maximize the realization of the first-in-first-out. Under this structure, the earliest feed into the bin can be discharged with priority, avoiding the quality degradation caused by long-term storage and making the feed freshness more uniform. When the steel plate silo adopts this design, the cone angle of the silo body should be controlled at 60 to 70 degrees, and the roughness of the inner wall Ra ≤ 0.8 microns, to ensure the smooth flow of feed.
Funnel flow unloading structure has obvious shortcomings, feed mainly from the center of the bottom of the bin outflow, around the feed is easy to stagnate, the formation of dead material area, dead material area volume can account for 15% to 20% of the capacity of the bin. The stagnant feed can be stored for 3 to 5 times longer than normal unloading feed, and the fat oxidation rate and mold contamination rate will increase, which will eventually be mixed with fresh feed and lower the overall feed quality.
From the cost point of view, the construction cost of the whole flow unloading structure is 25% to 30% higher than that of the hopper flow, mainly because of the additional inputs such as optimization of the cone angle of the silo and smooth treatment of the inner wall. For small farms, if the feed turnover is fast, more than once a week, the disadvantages of hopper flow can be partially mitigated, which can reduce the initial construction cost; but for large farms or feed storage cycle of more than two weeks, the overall flow structure, although the cost is high, but it can reduce the loss of feed, and the overall benefit is better in the long run.
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The role of silo materials in maintaining feed freshness
The smoothness of the inner wall of a steel plate silo directly affects feed residue and contamination risk. When the inner wall smoothness is not enough, feed particles are easy to adhere to the silo wall, forming a residual layer, the residual feed will gradually oxidize and deteriorate, and the next time when storing new feed, the deteriorated residue will be mixed into the new feed, resulting in cross-contamination. When the inner wall roughness Ra is controlled below 0.8 micron, the feed residue can be reduced to less than 0.1% of the silo capacity; if the roughness is more than 2.0 micron, the residue will rise to more than 0.5%, and the risk of contamination increases significantly.
Corrosion or aging of silo materials can directly jeopardize feed safety. Ordinary steel plate without anti-corrosion treatment, after 2 to 3 years of use will appear rust, corrosion products will be mixed into the feed, resulting in feed heavy metal content exceeds the standard, while the crevices produced by rust will become a breeding ground for microorganisms. Even with anticorrosion treatment, if the coating thickness is insufficient, the coating thickness per square meter is less than 80 microns, local corrosion will occur after 5 years of use, affecting feed safety.
Temperature control through silo design
The higher the temperature, the faster the nutrients in the feed degrade. Fatty acids in the feed, the oxidation rate at 25 ℃ environment is 2 times that of 15 ℃, and at 35 ℃, the oxidation rate will reach 4 times that of 15 ℃; B vitamins stored for a month at 30 ℃, the loss of the proportion of 15%, while at 20 ℃ environment, the loss of the proportion of only 5%. To slow down the loss of nutrients, it is vital to maintain a stable temperature in the bin.
High temperatures accelerate fat rancidity and vitamin loss, as well as making it easier for microorganisms to colonize. At temperatures above 30°C, the fatty acid price of feed can rise by 0.5 to 0.8 mg/g per month, and the loss of vitamin A can be as high as 8 to 10 percent per month; at temperatures above 35°C, mold reproduction becomes faster, and mycotoxin levels can increase by more than 20 percent per week, which can have a significant impact on the quality and safety of feed.
To keep the silo temperature stable, passive design methods such as silo body insulation, sunshade and natural ventilation can be used. Silo wall with composite thermal insulation structure, the outer layer is color coated steel plate, sandwiched between the thermal insulation layer, the inner layer of food-grade steel plate, can effectively block the external temperature conduction; silo roof with sunshade can reduce the direct sunlight brought about by the warming, summer can make the temperature inside the silo reduced by 3 to 5 ℃; reasonable setup silo roof and bottom of the vents, the use of thermal pressure ventilation principle to achieve the natural exchange of air per hour can be exchanged for the equivalent of the silo capacity of 0.3 times the volume of air, to help reduce the temperature inside the bin It can exchange air volume equal to 0.3 times of the silo capacity per hour, which helps to reduce the temperature inside the silo.
Silo structural hygiene, biosecurity and integrity
Gaps in the silo structure are the main means of entry for pests and contaminants. Pests, dust and rainwater can infiltrate and contaminate feed if gaps of more than 0.2mm are present at silo wall splices, doors and discharge openings. Pest reproduction will destroy feed particles, and their excreta will also lead to feed microbial overload, triggering intestinal diseases in animals.
Silo cleanliness is directly related to feed safety and animal disease prevention. If there is a dead space in the silo, residual feed can harbor microorganisms and pests that can contaminate new feed stored in subsequent years. Incompletely cleaned silos, the feed contamination rate can exceed 10%, increasing the probability of animal disease by 20% to 30%, increasing treatment costs and animal mortality.
A design that facilitates cleaning and inspection is key to safeguarding silo hygiene and biosecurity. The silo needs to avoid complex protrusions, and the inner corners are rounded with a radius of not less than 50 mm; the silo wall is set up with an inspection window of not less than 400 mm x 400 mm within every 5 meters; and the discharge port adopts a quick-opening structure to facilitate thorough cleaning of residual feed.
This type of design increases construction costs by 10 to 15 percent, and the sealing components of the fast-opening discharge opening require regular maintenance. Simplifying this type of design can reduce the initial cost, but it will increase the difficulty and time-consuming cleaning in the later stage, increasing the cleaning cost by more than 20% per year, and may also cause greater feed loss and breeding risk due to the inability to detect contamination problems in time.
Adaptability of silo design to different animal feed types
The physical and chemical properties of different animal feeds vary greatly, and the requirements for the storage environment and silo structure are also different, so there is no universal silo design that can be adapted to all feeds. Mismatch between silo design and feed type will result in reduced freshness, poor uniformity and, in severe cases, deterioration, thus affecting animal breeding results.
Silage has a high moisture content, usually between 60% and 70%, which requires high sealing and pressure resistance of the silo. The steel plate silo for storing this kind of feed needs to use high-strength steel plate with a thickness of not less than 4 mm, and the sealing performance should also reach the high airtight standard, so that the concentration of oxygen in the silo can be controlled at less than 1%, which can prevent the oxidization and deterioration of the silage. Silage fermentation will produce gas, the silo must be installed with a pressure relief valve to control the pressure relief at 0.02 to 0.03 MPa, to avoid damage to the silo due to excessive pressure. This specialized design costs 35% to 45% more than a normal feed silo, but guarantees the fermentation quality of the silage.
Pellet feed is harder and more fluid, but it is easy to absorb moisture and caking, so the silo’s moisture-proof effect and unloading smoothness are strictly required. The steel plate silo for storing pellet feed needs to strengthen the moisture-proof design, control the relative humidity inside the silo below 60%, and at the same time, adopt the overall flow unloading structure to avoid the pellet feed stagnation and caking in the silo. If the funnel flow structure is adopted, the caking rate of pellet feed will be more than 8%, the difficulty of unloading will increase, and the risk of feed deterioration will also rise.
Long-term stability of feed quality through rational silo design
Reasonable and stable silo design can make feed maintain consistent characteristics throughout the storage period. Good sealing, moisture-proof, temperature control and unloading structure design can make the temperature, humidity, oxygen content and other indicators of each area of the silo to maintain a balanced, the loss of feed nutrients can be controlled within 10%, the freshness can also be maintained uniformly, to avoid local environmental anomalies lead to deviations in feed quality.
Whether the silo design is reasonable or not is directly related to whether the animal feeding is stable. When feed quality and freshness remain stable, the fluctuation of animal feed intake will not be more than 5%, the growth situation is balanced, and the feed-to-weight ratio can be reduced by 3% to 5%; if the feed quality fluctuates a lot, the animal feed intake will obviously change, with fluctuations of more than 10%, and the growth rate will be uneven, and some of the animals will have health problems after consuming the deteriorated feeds, which will further increase the expenditure of the breeding side.
Silo is not just a simple feed storage facility, but should also bear the function of feed quality management. Relying on the scientific structural design and giving full play to the inherent advantages of the steel plate silo, it can extend the feed storage cycle, maintain stable quality and freshness, and provide basic support for the healthy growth of animals and the improvement of farming efficiency.