An animal feed formulator’s experience in formula design

The design of feed formula is a very interesting and logical job, and it also involves many dialectical things. A formula is not simply a mixture of several raw materials. It requires not only a deep understanding of animal physiology, biochemistry, and organic chemistry, but also a good memory of feeding standards, types and usage characteristics of feed raw materials, and nutritional components, and the ability to flexibly apply feeding standards according to actual conditions. The following are some of my experiences in formulating in a feed factory for your reference.

1 We must pay attention to the palatability of feed and the quality of raw materials. When making feed formulas, some formulators just mechanically input various feed raw materials into the formula software, and then click “linear programming”. As long as the nutritional content of the formula is reached, they print the formula and hand it over to production, and everything will be fine. In fact, this is extremely irresponsible. Although the nutrition of the formula is reached, the most important thing is whether the “customer” of the feed, the animal, likes it. Because the palatability of the feed is very poor, the animal will eat very little or simply refuse to eat. Therefore, when choosing raw materials, you must choose raw materials with good palatability, freshness and no deterioration. Formulators should not just sit in the office and make formulas in front of the computer every day. Every time before making a batch of feed, they must go to see the quality of the raw materials in person, and taste the palatability of the raw materials in person when necessary. In addition, when the feed is made, it is necessary to check whether the color and smell of the feed meet the standards. Some feed mills often like to make some special small packages of anti-stress, increase lean meat rate, and promote animal growth, because relatively speaking, this small package has a more obvious effect and higher profit. For example, I once made a small package of feed for controlling mosquitoes in farms. The main ingredient of this feed is cyromazine, which is mainly used to kill mosquito and fly eggs. When making this feed, I didn’t notice that the smell of cyromazine was quite unpleasant, so I just added some carriers and antibiotics to the formula. As a result, customers reported that pigs refused to eat feed with this feed. Later, when adjusting the formula, I added flavoring agents and sweeteners (milk feed flavor and sweetener from Valor company), and the market response to this feed has been very good. Another similar incident was that some customers complained that one of our company’s feed ingredients (the main ingredients were sulfonamide and sulfonamide enhancers) was not very effective in promoting growth. Later, we doubled the dosage of sulfonamide and sulfonamide enhancers. The result was the same as the previous example. The animals still refused to eat this feed ingredient. The reason was actually very simple. Because these drug additives have poor taste and palatability, when the dosage is increased, the unpleasant taste will inevitably increase. Therefore, we changed the dosage of sulfonamide and sulfonamide enhancers to 1.5 times the original dosage, and added some flavoring agents (milk feed flavor). As a result, the effect of the formula was much better.

One thing to emphasize is that we must pay attention to the quality of feed raw materials, such as rice bran, wheat bran and other raw materials. Fresh rice bran smells fresh and sweet in the mouth. It contains green bran shells. Generally speaking, it is fresh rice bran. This kind of rice bran can be used up to 50% in duck feed. However, due to its high fat content, rice bran is easy to go rancid (about 5 days), especially in the summer in southern China. Therefore, it is necessary to pay attention when using it in pig feed, because pigs have a very sensitive sense of smell. Try not to use it if possible, and you can use cassava instead. Wheat bran and second flour are actually two raw materials that are easy to go rancid, but many formulators ignore this point. Therefore, when using wheat bran, you must also pay attention to the freshness of the wheat bran, otherwise the animals will refuse to eat. Fish meal is a very good raw material, but the phenomenon of fish meal adulteration (urea, protein essence) is the most serious. Once, my company’s suckling pig feed had severe diarrhea. We tried to reduce the protein, add zinc oxide, and citric acid, but it could not be solved. Later, we had to send various raw materials for inspection. Other raw materials were normal, and only fish meal was found to be mixed with ammonium salts after testing. At that time, fish meal was removed from the formula, and the diarrhea problem was immediately solved. Because the quality of fish meal is difficult to control, some companies can buy dried fish themselves and then process it into fish meal. The price of dried fish is 3,400 yuan/ton, and the processing cost is 50 yuan/ton, which is cheaper than soybean meal. Such fish meal not only reduces costs, but also ensures quality.

2 Pay attention to the distortion of the formula

A good finished feed is determined by many factors, including: good feed formula, good raw materials and good processing technology, etc. An excellent formula is not difficult to make, but due to the actual quality of the raw materials, actual processing and other factors, the product cannot truly reflect the quality of the formula. The reasons are probably as follows:

①Variation of raw material nutrients. The reason for the variation is that even if the same raw material is produced in different places, environments, harvesting time, processing, storage and transportation methods, moisture, degree of mildew, etc., its nutrients will vary greatly. Therefore, the quality control department must provide the formulator with accurate nutrient data of various raw materials. Don’t assume that the protein content of soybean meal must be 43% or 46%, it may also be 44% or 40%. There is also corn. Generally speaking, the protein content of corn in Northeast China is relatively low, while the protein content of corn in Henan and Hebei is relatively high. Don’t think that corn is an energy feed and its protein does not need to be measured, because corn is used in a large proportion in feed formulas. If the protein content is one percentage point lower or higher, it will have a great impact on the nutritional content and cost of the formula. If the actual protein content of corn is 8%, and the protein content is taken as 8.7% when calculating the formula, the protein level of such a formula must not meet the actual nutritional needs of the animal. On the contrary, if the actual protein content of corn is 8.7, and it is taken as 8.0 when calculating the formula, such a formula not only wastes protein raw materials, but also invisibly increases the cost of the formula.

②The influence of various factors in the feed processing process. Because many formulators are purely animal nutritionists, they have little consideration for feed processing. They only consider making the formula and do not consider the impact of processing on the formula. There are many factors that cause formula distortion due to feed processing, including the impact of crushing particle size, mixing uniformity, ingredient accuracy and other aspects. Because various animals have different requirements for the particle size of feed, only when the particle size is reached can the animal achieve the best digestibility. There is also the problem of mixing uniformity, especially the uniformity of premixes. If the mixing is uneven, the animal may have insufficient trace elements and more likely to suffer from serious poisoning. Therefore, it is more necessary to pay attention to the influence of mixing uniformity and ingredient accuracy. Use a large scale for large amounts and a small scale for small amounts. If necessary, use step-by-step dilution to ensure that the drug additives are mixed evenly. The feed processing process will also affect the nutritional content. Some formulators say that there will be loss of raw materials during the processing, which will cause the actual nutritional content of the formula to be lower than the actual content of the formula, so a safety factor will be added when designing the formula. However, some formulators will lower some standards when making formulas, because the moisture in the raw materials will be lost during feed processing, resulting in the nutritional content in the feed being higher than the nutritional content in the formula. These two practices have their own rationality, but I think the best way is to take the feed to the laboratory to check the nutritional content after it is made to see if the formula is distorted.

3 Use scientific methods to formulate feed

With the continuous progress of animal nutrition, new diet technologies are becoming more and more mature. These technologies include: low-protein diet, application of net energy on monogastric animals, and diet formulation with digestible amino acids and proteins. The application of these technologies not only reduces the cost of formulation and the amount of nitrogen excreted, but also makes the nutrients in the formulation closer to the nutritional needs of animals.

In particular, the application of low-protein diet technology in pig feed has been very mature. The protein level of pig feed can now be reduced by 3-4% to achieve the same growth performance as high-protein diet, but when reducing protein, the following points must be paid attention to:

㈠The energy and lysine levels of low-protein diets must be consistent with those of high-protein diets;

㈡Use amino acid balance mode to formulate diets;

㈢Add monomeric amino acids to diets;

㈣The essential amino acid level of mixed meal diets should be corrected by amino acid ileal true digestibility (pigs) or amino acid true digestibility (chickens).

However, for broiler feed, it is difficult to reduce it by 1-2%. The data requirements for broiler chickens are strict. If pig feed is a 1,000-meter run, then broiler chickens are a 100-meter run. However, low-protein broiler chicken diets should be the hotspot and focus of future animal nutrition research. Soybean meal cannot always be at a low price. The international situation is changing rapidly. Once protein conservation is successful, its economic value is immeasurable.

Another is the application of net energy on monogastric animals. When using digestible energy or metabolizable energy, the energy of protein or fiber is overestimated, while the energy of carbohydrates is underestimated. For example, corn and soybean meal have similar ME and DE, but if you compare their NE, corn NE is 2650 and soybean meal NE is 1940. Therefore, when using DE to design a formula, the formula is unreasonable and uneconomical. However, there is a lack of NE data for various raw materials. We can refer to Ajinomoto’s net energy calculator. When using net energy to make a formula, the cost per ton of feed can be reduced by 5-7 yuan.

The last technology is to use digestible amino acids to formulate a diet. Let’s take a simple example. Some formulators use 13% soybean meal when making egg duck feed, while some formulators do not use soybean meal at all, but they also achieve the same production level as a high-dosage soybean meal diet. What is the reason? The answer is to use digestible amino acids to formulate mixed meal diets. Of course, pure corn and soybean meal can easily formulate a nutritionally balanced diet, but now corn and soybean meal have become extremely expensive. A formulator who uses corn and soybean meal diets all day will inevitably lead to the decline of a feed company. It can be said that the ability to use digestible amino acid values ​​is now the key to the success of the lowest cost feed formulation. Since pigs have high requirements for the palatability of feed, it is unlikely that pure mixed meal diets will be used in pig diets. Since poultry have an underdeveloped sense of taste, we can safely and boldly use the digestible amino acid model, and should abandon the idea of ​​using a large amount of soybean meal in the formulation of laying ducks and chicks (ducks). There are already a lot of data on the true digestibility of amino acids in chicken feed, but there is very little data on ducks in this regard. Generally, they are based on chickens. However, this method often underestimates the nutritional value of various raw materials to ducks, because ducks have a greater digestive capacity than chickens. Even if the formulation is made with such reference values, it is usually better than the formulation with total amino acid values.

4 Formulate duck feed according to the growth characteristics of ducks

Meat ducks have the characteristics of fast growth and high feed return. In recent years, duck farming has developed rapidly. However, the nutritional research on ducks has not kept up with the development of the meat duck farming industry. In particular, many formulators are unsure when formulating duck feed because there is very little data on ducks. For example, the metabolizable energy of soybean meal is 2856Mcal/KG for ducks and 2467Mcal/KG for chickens. Therefore, it is unscientific to refer to the metabolizable energy value of chicken feed in the formula. NRC has sufficient data on digestible amino acids for pigs and chickens, but there are few reports on digestible amino acids for ducks. Therefore, if you want to use digestible amino acids to formulate duck feed, you must refer to the data of chickens. The digestive capacity of ducks is much greater than that of chickens, especially medium and large ducks. The daily feed intake is about 0.2kg, while that of medium and large chickens is only 0.1kg. Therefore, the feed intake of ducks must be considered when formulating duck feed. If the protein of medium-sized chicken is set to 17 and the energy is 3000 Mcal/KG, the protein of medium-sized duck can be set to between 12.5-16% and the energy can be set to 2350-2600Mcal/KG. Because when we formulate feed, we must consider the egg-energy ratio and daily feed intake. As long as the egg-energy ratio of medium-sized duck is kept above 45, a good production performance can be achieved. The feed intake of ducks is relatively large, so when setting the energy-protein level of ducks, there can be a relatively large range of variation compared with the nutritional level of broilers. For laying ducks, since the energy requirement is not high, the energy is kept at 2400-2600Mcal/KG, the protein is kept above 16.5, and the minimum energy-egg ratio is 70 to achieve the maximum egg production rate and egg weight.

In short, feed formula design is a highly technical and artistic job, which requires a high level of theoretical guidance and the summary of accumulated experience. Only if we study, think and practice more can we make a very cost-effective formula.