Preparation method and application of lactating cow premix for improving chronic stress state

Abstract

The invention relates to a preparation method and application of a lactating cow premix for improving a chronic stress state, and the lactating cow premix comprises the following components in percentage by mass: 25-40% of a carrier, 0.01-0.05% of an antioxidant, 2-8% of vitamins, 40-60% of minerals, 0.5-2% of probiotics, 1-5% of saccharomyces cerevisiae, 5-10% of lysine, 0.01-0.05% of chromium methionine and 2-5% of curcumin. The preparation method comprises the following steps: weighing the components in proportion, adding the components into a mixer, mixing for 20-40 minutes, packaging, and inspecting. The lactating dairy cow premix for improving the chronic stress state can effectively relieve the chronic stress condition of dairy cows, reduce the probability that the dairy cows suffer from mastitis and digestive tract diseases in the stress period, improve the resistance and immune function of the lactating dairy cows, increase the milk yield and improve the milk quality, and is balanced in formula nutrition, simple in preparation method and low in cost. The feed additive can be directly added into feed and has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of feed additive technology, specifically relating to a method for preparing a premix for lactating dairy cows to improve chronic stress and its application. Background Technology

[0002] Chromium methionine is an important organic chromium complex (or chelate), whose core technology lies in using amino acid chelation technology to enhance the levels of the essential trace element chromium (Cr). 3+ The bioavailability and physiological activity of methionine chromium. Methionine chromium is composed of specific functional groups (mainly amino and carboxyl groups) of the essential amino acid L-methionine and trivalent chromium ions (Cr). 3+ The stable ring structure (chelate) formed through coordination bonds is not accidental; its core purpose is to mimic the form in which trace elements are more easily absorbed and utilized in organisms. Traditional methods of supplementing animals with chromium often use inorganic chromium salts (such as chromium chloride and chromium sulfate), but their absorption rate in vivo is generally low (usually <3%), and they are easily interfered with by gastrointestinal environmental factors, limiting their supplementation effect. The chelate structure protects chromium ions from binding or precipitation by substances such as phytic acid and fiber in the gastrointestinal tract, improving their stability. At the same time, this organic form is more easily recognized and utilized by tissues, potentially reaching target sites more effectively (such as participating in the formation or activation of glucose tolerance factor) and exerting physiological regulatory functions.

[0003] In addition, chromium methionine not only provides chromium, but the L-methionine in its molecular structure is also an important sulfur-containing essential amino acid that participates in various physiological processes such as protein synthesis and methyl donors, providing potential synergistic nutritional effects.

[0004] The essence of chromium methionine technology lies in using an advanced chelation process to combine the essential trace element chromium with a specific amino acid (DL-methionine), creating a trace element supplement that is structurally closer to its natural active form in organisms, more efficiently absorbed and utilized, and more targeted in its function. This technical approach effectively solves the core problem of low absorption and utilization rates of inorganic chromium salts, laying the scientific foundation for its application in human nutrition supplementation, animal feed additives, and food fortification, and becoming an important development direction in trace element nutritional fortification technology.

[0005] Curcumin is a natural polyphenolic compound extracted from the rhizomes of plants in the genus Curcuma (such as turmeric and Chinese turmeric). Due to its unique chemical structure and rich biological activities, such as anti-inflammatory, antioxidant, and metabolic regulatory effects, it has been widely studied and applied in food additives, pharmaceutical research and development, and cosmetics, and is currently one of the hot research topics in the field of natural products. However, because curcumin is insoluble in water, its crystalline powder is not easily dispersed into single molecules, resulting in extremely low absorption rate and bioavailability, which affects its efficacy.

[0006] Chinese invention patent CN118000318A discloses a premixed feed for lactating dairy cows, its preparation method, and its application. The feed consists of the following ingredients in parts by weight: carrier 1-5%, antioxidant 0.01-0.05%, probiotics 0.01-0.05%, allicin 0.1-0.5%, minerals 70-80%, lysine 8-12%, methionine 1-5%, brewer's yeast 1-5%, Aspergillus oryzae fermentation complex enzyme 1-5%, and chromium propionate 0.01-0.05%. This invention provides balanced nutrition for lactating dairy cows, helps improve their resistance and immune function, enhances milk quality, and increases the economic benefits for farmers. However, the inorganic chromium salts used have low absorption and utilization rates, limiting their effect on chromium supplementation in lactating dairy cows.

[0007] Another Chinese invention patent, CN101773215B, discloses a special compound premix for dairy cows lactating in summer and its application. Its characteristic is that it is composed of the following components and weight ratios: 0.8–1.2 parts ferric sulfate, 0.5–1.0 parts manganese sulfate, 0.9–1.4 parts zinc sulfate, 0.1–0.31 parts copper sulfate, 0.1–0.2 parts potassium iodide (1%), 0.21–0.41 parts cobalt sulfate (1%), 0.13–0.33 parts sodium selenite (1%), 0.07–0.12 parts vitamin A, 0.06–0.09 parts vitamin D, 0.5–1.0 parts vitamin E, 0.5–0.85 parts dihydropyridine, and 82.41–92.33 parts carrier. This invention can effectively alleviate the impact of high summer temperatures on dairy cow production performance, effectively maintain the normal physiological functions (normal body temperature and respiratory rate) of lactating dairy cows in summer, effectively increase the milk yield of lactating dairy cows in high summer temperatures, and delay the trend of declining milk yield in the later stages of lactation. However, it does not improve the immune function of lactating dairy cows or the quality of the milk produced. Summary of the Invention

[0008] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.

[0009] To achieve these objectives and other advantages according to the invention, a premix for improving chronic stress in lactating dairy cows is provided, comprising, by weight percentage: 25-40% carrier, 0.01-0.05% antioxidant, 2-8% vitamins, 40-60% minerals, 0.5-2% probiotics, 1-5% brewer's yeast, 5-10% lysine, 0.01-0.05% chromium methionine, and 2-5% curcumin; wherein the chromium methionine is added to the feed at a rate of 4-8 mg / head / day or 0.16-0.32 mg / kg.

[0010] Preferably, the carrier is rice husk powder; the antioxidant is one or more of zinc sulfate, butylated hydroxytoluene, and propyl gallate. Preferably, the vitamin is one or more of vitamin A, vitamin D, vitamin E, and niacin; and the mineral is one or more of calcium carbonate, calcium hydrogen phosphate, calcium phosphate, magnesium oxide, sodium chloride, ferric sulfate, zinc sulfate, copper sulfate, manganese sulfate, selenium-enriched yeast, and cobalt chloride hexahydrate.

[0011] Preferably, the probiotic is one or more of Bacillus amyloliquefaciens and Bacillus subtilis.

[0012] Preferably, the method for preparing the chromium methionine includes the following steps: A. Add methionine to water, stir well, heat to 60-80℃, add trivalent chromium salt and stir until completely dissolved; B. Add an alkaline substance to the mixed solution in step one, maintain the reaction temperature at 60-80℃ until precipitation is complete, filter and dry to obtain chromium methionine.

[0013] Preferably, in A, the trivalent chromium salt is one or more of chromium sulfate, chromium chloride, and chromium formate; the mass-to-volume ratio of methionine, water, and trivalent chromium salt is 5g:100ml:1-5g.

[0014] Preferably, in B, the alkaline substance is one or more of sodium hydroxide, sodium carbonate, and potassium hydroxide; the molar ratio of the alkaline substance to the trivalent chromium salt is 1 to 3:1.

[0015] Preferably, the curcumin is replaced with a glucosyl-β-cyclodextrin-curcumin nanocomplex, and the preparation method of the glucosyl-β-cyclodextrin-curcumin nanocomplex includes the following steps: S1. Weigh 6-10 parts by weight of glucosyl-β-cyclodextrin and add it to 100 parts of deionized water. Sonicate the mixture for 10-15 minutes at an ultrasonic power of 300-500W and an ultrasonic temperature of 40-60℃ to obtain an aqueous solution of glucosyl-β-cyclodextrin. Weigh 0.1-0.2 parts of curcumin and dissolve it in 10 parts of 90% ethanol solution to obtain a curcumin ethanol solution. S2. Heat the curcumin ethanol solution and the glucosyl-β-cyclodextrin aqueous solution to 40-60°C. Slowly add the curcumin ethanol solution dropwise to the glucosyl-β-cyclodextrin aqueous solution while stirring at a rate of 500-700 rpm. After stirring until homogeneous, microwave sonicate with ultraviolet light at a wavelength of 360-400 nm for 20-30 minutes. The microwave power is 200-300 W, the ultrasonic power is 150-250 W, the ultrasonic frequency is 25-40 kHz, and the reaction temperature is 40-60°C to form a homogeneous solution. S3. Filter the solution formed in S3 through a 0.45μm microporous membrane, and then pour it into a high-pressure homogenizer. The pressure is 600-1000 bar, the temperature is controlled at 20-30℃, and the cycle is repeated 2-4 times. S4. The solution obtained in S4 is dispensed into freeze-drying bottles and pre-frozen in a -80℃ freezer for 2 to 4 hours. Then it is transferred to a freeze dryer and freeze-dried for 12 to 24 hours at a temperature of -50 to -40℃ and a vacuum degree of <10Pa to obtain glucosyl-β-cyclodextrin-curcumin nano-inclusion complex.

[0016] The present invention also provides a method for preparing a premix for lactating cows to improve chronic stress, comprising: weighing a carrier, antioxidant, vitamins, minerals, probiotics, brewer's yeast, lysine, chromium methionine and curcumin in proportion, adding them into a mixing tank and mixing thoroughly for 20-40 minutes, packaging, and testing.

[0017] The present invention also provides the application of the lactating cow premix prepared according to the above preparation method for improving chronic stress in dairy cow feeding.

[0018] The present invention has at least the following beneficial effects: (1) The chromium methionine added to the premixed feed for lactating cows prepared in this invention for improving chronic stress serves as a provider of the trace elements chromium and methionine required by both animals. This helps improve the absorption and utilization of chromium in lactating cows, exerts physiological regulatory functions, reduces cortisol secretion under stress, alleviates insulin antagonism, thereby maintaining stable blood sugar levels and enhancing immune cell activity. Simultaneously, it effectively alleviates chronic stress in dairy cows, reduces the probability of mastitis and digestive tract diseases during the stress period, and improves the resistance and immune function of lactating cows.

[0019] (2) The curcumin added to the premix for lactating cows prepared in this invention to improve chronic stress can reduce mammary gland inflammation caused by infection in lactating cows. By clearing excess reactive oxygen species in the body, it reduces the level of oxidative stress caused by heat stress and alleviates heat stress damage. In the glucosyl-β-cyclodextrin-curcumin nanocomposite prepared in this invention, glucosyl-β-cyclodextrin is a water-soluble cyclodextrin derivative obtained by chemical modification of β-cyclodextrin. Its core advantage is that by introducing glucose, it solves the problems of poor water solubility and low bioavailability of β-cyclodextrin, while retaining the core function of β-cyclodextrin as a "hydrophobic cavity inclusion of guest molecules". The glucosyl-β-cyclodextrin is included with curcumin, and the curcumin is accelerated to glucose by microwave-ultrasound-ultraviolet method, which uses microwave to rapidly heat up the mixture. The diffusion process within the cavities of glucosyl-β-cyclodextrin involves ultrasound to uniformly disperse curcumin in the aqueous phase, increasing the contact area with cyclodextrin. Ultraviolet light further activates the reactants at the molecular level, facilitating the entry of hydrophobic curcumin into the cavities of glucosyl-β-cyclodextrin. This triple synergistic effect enhances the inclusion rate of glucosyl-β-cyclodextrin and curcumin. The resulting glucosyl-β-cyclodextrin-curcumin nanocomplex effectively improves the water solubility of curcumin and simultaneously enhances the absorption and utilization rate of curcumin in lactating cows.

[0020] (3) Animal experiments have shown that adding the lactating cow premix of the present invention to the feed of dairy cows has a significant improvement effect, which is conducive to the rapid absorption of various special energy substances by dairy cows, and can increase milk yield and improve milk quality, effectively increasing the content of milk fat and milk protein in milk. The preparation method of the present invention is simple, the formula is nutritionally balanced, and it can be directly added to the feed, with broad application prospects.

[0021] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Detailed Implementation

[0022] The present invention will now be described in further detail so that those skilled in the art can implement it based on the description.

[0023] Example 1 A premix for lactating dairy cows to improve chronic stress, comprising 1000g of raw materials and the following components: Rice husk powder 280g, zinc sulfate 0.2g, vitamin A 0.7g, vitamin D 0.6g, vitamin E 5g, calcium carbonate 568.4g, hydrolyzed amyloliquefaciens 10g, brewer's yeast 25g, glucosyl-β-cyclodextrin-curcumin nanocomplex 20g, lysine 90g, and chromium methionine 0.1g.

[0024] The preparation method of chromium methionine includes the following steps: Step 1: Add 25g of methionine to 500mL of water, stir well, heat to 80℃, add 25g of chromium chloride and stir until completely dissolved; Step 2: Add 6.7g of sodium hydroxide to the mixed solution in Step 1, maintain the reaction temperature at 80℃, until precipitation is complete, filter and dry to obtain chromium methionine.

[0025] The preparation method of glucosyl-β-cyclodextrin-curcumin nanocomplex includes the following steps: S1. Weigh 6g of glucosyl-β-cyclodextrin and add it to 100ml of deionized water. Sonicate the solution for 15min at an ultrasonic power of 300W and an ultrasonic temperature of 40℃ to obtain an aqueous solution of glucosyl-β-cyclodextrin. Weigh 0.15g of curcumin and dissolve it in 10ml of 90% ethanol solution to obtain a curcumin ethanol solution. S2. Heat the curcumin ethanol solution and the glucosyl-β-cyclodextrin aqueous solution to 50°C. Slowly add the curcumin ethanol solution dropwise into the glucosyl-β-cyclodextrin aqueous solution while stirring at a stirring rate of 500 rpm. After stirring evenly, microwave sonicate with ultraviolet light at a wavelength of 365 nm for 25 min. The microwave power is 250 W, the ultrasonic power is 200 W, the ultrasonic frequency is 30 kHz, and the reaction temperature is 50°C to form a homogeneous solution. S3. Filter the solution formed in S3 through a 0.45μm microporous membrane, then pour it into a high-pressure homogenizer at a pressure of 800 bar and a temperature of 30℃, and repeat the cycle twice. S4. The solution obtained in S4 was dispensed into freeze-drying bottles and pre-frozen in a -80℃ freezer for 2 hours. Then it was transferred to a freeze dryer and freeze-dried for 18 hours at a temperature of -50℃ and a vacuum degree of <10Pa to obtain glucosyl-β-cyclodextrin-curcumin nano-inclusion complex.

[0026] A method for preparing a premix for lactating dairy cows to improve chronic stress includes the following steps: Weigh out the appropriate amounts of rice husk powder, zinc sulfate, vitamin A, vitamin D, vitamin E, calcium carbonate, Bacillus amyloliquefaciens, Saccharomyces cerevisiae, glucosyl-β-cyclodextrin-curcumin nanocomplex, lysine, and chromium methionine, and put them into a mixing tank. Mix thoroughly for 30 minutes. After mixing, package the products. Once the packaged products pass inspection, they can be stored in the warehouse.

[0027] Example 2 A method for preparing a premix for lactating dairy cows to improve chronic stress, wherein the total weight of the raw materials is 1000g, and the premix comprises the following components: Rice husk powder 280g, zinc sulfate 0.2g, vitamin A 0.7g, vitamin D 0.6g, vitamin E 5g, calcium carbonate 568.3g, hydrolyzed amyloliquefaciens 10g, brewer's yeast 25g, glucosyl-β-cyclodextrin-curcumin nanocomplex 20g, lysine 90g, and methionine chromium 0.2g.

[0028] The preparation methods for chromium methionine, glucosyl-β-cyclodextrin-curcumin nanocomplexes and premixes for improving chronic stress in lactating cows are the same as in Example 1.

[0029] Example 3 A method for preparing a premix for lactating dairy cows to improve chronic stress, wherein the total weight of the raw materials is 1000g, and the premix comprises the following components: Rice husk powder 280g, zinc sulfate 0.2g, vitamin A 0.7g, vitamin D 0.6g, vitamin E 5g, calcium carbonate 568.2g, hydrolyzed Bacillus amyloliquefaciens 10g, brewer's yeast 25g, glucosyl-β-cyclodextrin-curcumin nanocomplex 20g, lysine 90g, and methionine chromium 0.3g.

[0030] The preparation methods for chromium methionine, glucosyl-β-cyclodextrin-curcumin nanocomplexes and premixes for improving chronic stress in lactating cows are the same as in Example 1.

[0031] Example 4 A method for preparing a premix for lactating dairy cows to improve chronic stress, wherein the total weight of the raw materials is 1000g, and the premix comprises the following components: Rice husk powder 280g, zinc sulfate 0.2g, vitamin A 0.7g, vitamin D 0.6g, vitamin E 5g, calcium carbonate 568.1g, hydrolyzed amyloliquefaciens 10g, brewer's yeast 25g, glucosyl-β-cyclodextrin-curcumin nanocomplex 20g, lysine 90g, and methionine chromium 0.4g.

[0032] The preparation methods for chromium methionine, glucosyl-β-cyclodextrin-curcumin nanocomplexes and premixes for improving chronic stress in lactating cows are the same as in Example 1.

[0033] Example 5 A method for preparing a premix for lactating dairy cows to improve chronic stress, wherein the total weight of the raw materials is 1000g, and the premix comprises the following components: Rice husk powder 280g, zinc sulfate 0.2g, vitamin A 0.7g, vitamin D 0.6g, vitamin E 5g, calcium carbonate 568g, hydrolyzed amyloliquefaciens 10g, brewer's yeast 25g, glucosyl-β-cyclodextrin-curcumin nanocomplex 20g, lysine 90g and chromium methionine 0.5g.

[0034] The preparation methods for chromium methionine, glucosyl-β-cyclodextrin-curcumin nanocomplexes and premixes for improving chronic stress in lactating cows are the same as in Example 1.

[0035] Example 6 A premix for lactating dairy cows to improve chronic stress, comprising 1000g of raw materials and the following components: Rice husk powder 280g, zinc sulfate 0.2g, vitamin A 0.7g, vitamin D 0.6g, vitamin E 5g, calcium carbonate 568.4g, hydrolyzed amyloliquefaciens 10g, brewer's yeast 25g, curcumin 20g, lysine 90g and methionine chromium 0.1g.

[0036] The preparation methods for chromium methionine and premixed feed for lactating cows to improve chronic stress are the same as in Example 1.

[0037] Example 7 A premix for lactating dairy cows to improve chronic stress, comprising 1000g of raw materials and the following components: Rice husk powder 280g, zinc sulfate 0.2g, vitamin A 0.7g, vitamin D 0.6g, vitamin E 5g, calcium carbonate 568.4g, hydrolyzed amyloliquefaciens 10g, brewer's yeast 25g, glucosyl-β-cyclodextrin-curcumin nanocomplex 20g, lysine 90g, and chromium methionine 0.1g.

[0038] The preparation method of chromium methionine includes the following steps: Step 1: Add 25g of methionine to 500mL of water, stir well, heat to 80℃, add 25g of chromium chloride and stir until completely dissolved; Step 2: Add 6.7g of sodium hydroxide to the mixed solution in Step 1, maintain the reaction temperature at 80℃, until precipitation is complete, filter and dry to obtain chromium methionine.

[0039] The preparation method of glucosyl-β-cyclodextrin-curcumin nanocomplex includes the following steps: S1. Weigh 6g of glucosyl-β-cyclodextrin and add it to 100ml of deionized water. Sonicate the solution for 15min at an ultrasonic power of 300W and an ultrasonic temperature of 40℃ to obtain an aqueous solution of glucosyl-β-cyclodextrin. Weigh 0.15g of curcumin and dissolve it in 10ml of 90% ethanol solution to obtain a curcumin ethanol solution. S2. Heat the curcumin ethanol solution and the glucosyl-β-cyclodextrin aqueous solution to 50°C. Slowly add the curcumin ethanol solution dropwise to the glucosyl-β-cyclodextrin aqueous solution while stirring at a speed of 500 rpm. Maintain the temperature at 50°C. After the addition is complete, continue stirring for 2 hours to form a homogeneous solution. S3. Filter the solution formed in S3 through a 0.45μm microporous membrane, then pour it into a high-pressure homogenizer at a pressure of 800 bar and a temperature of 30℃, and repeat the cycle twice. S4. The solution obtained in S4 was dispensed into freeze-drying bottles and pre-frozen in a -80℃ freezer for 2 hours. Then it was transferred to a freeze dryer and freeze-dried for 18 hours at a temperature of -50℃ and a vacuum degree of <10Pa to obtain glucosyl-β-cyclodextrin-curcumin nano-inclusion complex.

[0040] A method for preparing a premix for lactating dairy cows to improve chronic stress includes the following steps: Weigh out the appropriate amounts of rice husk powder, zinc sulfate, vitamin A, vitamin D, vitamin E, calcium carbonate, Bacillus amyloliquefaciens, Saccharomyces cerevisiae, glucosyl-β-cyclodextrin-curcumin nanocomplex, lysine, and chromium methionine, and put them into a mixing tank. Mix thoroughly for 30 minutes. After mixing, package the products. Once the packaged products pass inspection, they can be stored in the warehouse.

[0041] Comparative Example 1 The difference from Example 3 is that chromium methionine is not added.

[0042] Comparative Example 2 Compared to Example 3, the difference is that chromium methionine is replaced with the same weight of chromium yeast.

[0043] Comparative Example 3 Compared with Example 3, the difference is that chromium methionine is replaced with the same weight of chromium propionate.

[0044] The premixes prepared in Examples 1-7 and Comparative Examples 1-3 for improving chronic stress in lactating dairy cows were applied to their feed to determine their effect on stress levels. A total of 110 Holstein dairy cows of similar age, weight, parity, and lactation days were randomly assigned to 11 groups of 10 cows each. One group served as the control group, fed a basal diet daily; the other 10 groups served as the experimental groups, fed a basal diet supplemented with the premixes prepared in Examples 1-7 and Comparative Examples 1-3 according to the proportions in Table 1, for a total of 30 days.

[0045] Table 1 Detection indicators and measurement methods: All experimental cows were milked three times daily, and milk yield was recorded at each milking session to calculate the average daily milk yield for each group. Every five days, a mixed milk sample from each group was collected, and the protein and fat content was detected using a dairy infrared scanner. Simultaneously, somatic cell counts were performed on the mixed milk sample using a somatic cell counter. The data results are expressed as the average value ± standard error of each of the above-mentioned indicators.

[0046] Blood samples were collected from all experimental dairy cows on days 0, 10, 20, and 30 of the experiment via intravenous collection. The plasma glucose concentration was determined using an automated biochemical analyzer; non-esterified fatty acids (NEFA) were determined using a colorimetric method; β-hydroxybutyrate (BHBA) was determined using an ELISA method; and cortisol levels were determined using a chemiluminescent immunoassay. The data are presented as averages of the above-mentioned indicators.

[0047] The results of the milk yield and milk quality measurements are shown in Table 2.

[0048] Table 2 The test results of biochemical indicators in the blood are shown in Table 3.

[0049] Table 3 As shown in Table 1, compared with the control group, Examples 1-7 and Comparative Examples 1-3 showed a significant increase in milk yield, improved milk protein and fat content, and decreased somatic cell count in lactating cows. This indicates that adding the premixes prepared in Examples 1-7 and Comparative Examples 1-3 to the feed can increase the intake of nutrients in lactating cows, improve milk yield and quality, and effectively increase the content of milk fat and protein. Compared with Comparative Examples 1-3, Examples 1-7 reduced somatic cell count, while maintaining it within a healthy range. This suggests that the addition of chromium methionine is beneficial for the absorption and utilization of chromium in lactating cows, exerting physiological regulatory functions, improving the immunity of lactating cows, effectively reducing the risk of diseases such as mastitis, and effectively alleviating chronic stress in dairy cows. Compared with Examples 1-5 and Example 7, Example 6 showed a higher somatic cell count, indicating that the unencapsulated curcumin was less effective in reducing inflammation in lactating cows than the glucosyl-β-cyclodextrin-curcumin nanocomplex, resulting in lower absorption and utilization rates in lactating cows. Furthermore, compared with Examples 1-5, Example 7 demonstrated that the microwave-ultrasound-ultraviolet method improved the inclusion rate of the glucosyl-β-cyclodextrin-curcumin nanocomplex, increasing its absorption and utilization rates in lactating cows, resulting in a lower somatic cell count in milk and reducing the risk of diseases such as mastitis in dairy cows.

[0050] As shown in Table 2, compared with Comparative Examples 1-3, Examples 1-7 increased blood glucose concentration and decreased the concentrations of non-esterified fatty acids and β-hydroxybutyrate, indicating that adding lactating cow premix to the diet to improve chronic stress can significantly improve the energy status of dairy cows. At the same time, the reduction in cortisol in Examples 1-7 can alleviate the antagonistic effect of insulin, thereby maintaining blood glucose stability, enhancing immune cell activity, and reducing the occurrence of stress.

[0051] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. A pre-mix for improving the chronic stress status of a lactating dairy cow, characterized in that, According to the mass percentage, the following components are included: carrier 25-40%, antioxidant 0.01-0.05%, vitamin 2-8%, mineral 40-60%, probiotic 0.5-2%, Saccharomyces cerevisiae 1-5%, lysine 5-10%, methionine chromium 0.01-0.05%, and curcumin 2-5%; The amount of methionine chromium added in the feed is 4-8 mg per head per day or 0.16-0.32 mg / kg.

2. The pre-mix for improving the chronic stress status of a lactating cow according to claim 1, characterized in that, The carrier is bram; the antioxidant is one or more of zinc sulfate, butylated hydroxytoluene, and propyl gallate.

3. The pre-mix for improving the chronic stress status of a lactating dairy cow according to claim 1, wherein The vitamin is one or more of vitamin A, vitamin D, vitamin E, and niacin; the mineral is one or more of calcium carbonate, calcium hydrogen phosphate, calcium phosphate, magnesium oxide, sodium chloride, ferrous sulfate, zinc sulfate, copper sulfate, manganese sulfate, selenium-rich yeast, and cobalt chloride hexahydrate.

4. The pre-mix for improving the chronic stress status of a lactating dairy cow according to claim 1, wherein The probiotic is one or more of Bacillus amyloliquefaciens and Bacillus subtilis.

5. The pre-mix for improving the chronic stress status of a lactating dairy cow according to claim 1, wherein The preparation method of methionine chromium includes the following steps: A. Add methionine into water, stir until uniform, heat to 60-80℃, add trivalent chromium salt and stir until completely dissolved; B. Add alkaline substance to the mixed solution in step one, keep the reaction temperature at 60-80℃, until the precipitation is complete, filter and dry to obtain methionine chromium.

6. The method for preparing chromium methionine as described in claim 5, characterized in that, In the A, the trivalent chromium salt is one or more of chromium sulfate, chromium chloride, and chromium formate; the mass-volume ratio of methionine, water, and trivalent chromium salt is 5g:100ml:1-5g.

7. The method for preparing chromium methionine as described in claim 5, characterized in that, In the B, the alkaline substance is one or more of sodium hydroxide, sodium carbonate, and potassium hydroxide; the molar ratio of alkaline substance to trivalent chromium salt is 1-3:

1.

8. The pre-mix for improving the chronic stress status of a lactating dairy cow according to claim 1, wherein The curcumin is replaced by glucosyl-β-cyclodextrin-curcumin nano-inclusion compound, and the preparation method of glucosyl-β-cyclodextrin-curcumin nano-inclusion compound includes the following steps: S1. According to weight parts, 6-10 parts of glucosyl-β-cyclodextrin are weighed into 100 parts of deionized water, ultrasonic treatment is carried out under the condition of ultrasonic power 300-500 W and ultrasonic temperature 40-60℃ for 10-15 min to obtain a glucosyl-β-cyclodextrin aqueous solution; 0.1-0.2 parts of curcumin is dissolved in 10 parts of 90% ethanol solution to obtain a curcumin ethanol solution; S2. The curcumin ethanol solution and the glucosyl-β-cyclodextrin aqueous solution are heated to 40-60℃, the curcumin ethanol solution is slowly dropped into the glucosyl-β-cyclodextrin aqueous solution, and stirring is carried out while dropping, the stirring rate is 500-700 rpm; after uniform stirring, ultraviolet light with a wavelength of 360-400 nm is used for auxiliary microwave ultrasonic treatment for 20-30 min, the microwave power is 200-300 W, the ultrasonic power is 150-250 W, the ultrasonic frequency is 25-40 kHz, and the reaction temperature is 40-60℃, forming a uniform solution; S3. The solution formed in S3 is filtered with a 0.45 μm microporous filter membrane, then poured into a high-pressure homogenizer, the pressure is 600-1000 bar, the temperature is controlled at 20-30℃, and the cycle is 2-4 times. S4, the solution obtained in S4 is divided into freeze-drying bottles, and is pre-frozen in a refrigerator at -80℃ for 2-4 hours, and then is transferred into a freeze-drying machine, and is freeze-dried at a temperature of -50 to -40℃ and under a vacuum degree of <10 Pa for 12-24 hours to obtain a glucosyl-β-cyclodextrin-curcumin nano-inclusion compound.

9. A method for the preparation of a pre-mix for improving the chronic stress status of a lactating cow according to any one of claims 1 to 8, characterized in that, Comprise: The carrier, antioxidant, vitamin, mineral, probiotic, Saccharomyces cerevisiae, lysine, methionine chromium and curcumin are weighed according to the proportion, put into a mixing tank and mixed for 20-40 min, packaged, inspected, and then finished.

10. Use of a premix for improving the chronic stress state of a lactating dairy cow, prepared according to the method of any one of claims 1-9, in the feeding of dairy cows.

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