Application of pyridoxine and / or pyridoxal in predicting lactation performance of lactating cow

Abstract

The invention belongs to the technical field of dairy cow lactation performance prediction, and particularly relates to application of pyridoxine and / or pyridoxal in prediction of lactation performance of dairy cows. By detecting the content of B vitamins in the serum of the dairy cow and performing correlation analysis on the serum and the lactation performance of the dairy cow, the result shows that the content of pyridoxine and / or pyridoxal in the serum is closely related to the lactation performance of the dairy cow, and the method has the characteristics of high sensitivity and high accuracy, can be applied to prediction of the lactation performance of the dairy cow, shortens the screening period of low-yield cattle herds, and improves the screening efficiency of the dairy cow herds. And economic losses in the aspects of feed, labor and the like caused by a traditional elimination procedure are reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of dairy cow lactation performance prediction, and particularly relates to application of pyridoxinic acid and / or pyridoxine in predicting lactation performance of lactating dairy cows. BACKGROUND

[0002] Dairy cows are an important part of animal husbandry, and their lactation performance not only affects the yield and nutritional value of dairy products, but also directly determines the market economic benefits of dairy products. At present, in the production of animal husbandry, low-yield dairy cows are still determined by recording the milk yield of lactating dairy cows. However, the existing method for screening low-yield cows is long in cycle and high in investment, and low-yield cows are usually culled in the late lactation period, which increases the additional feed input of the farm for a lactation cycle of low-yield cows, which is not conducive to reducing the operating cost of the farm. Therefore, there is currently a lack of systematic research on predicting the lactation performance of dairy cows.

[0003] B vitamins are the biosynthetic precursors of most essential cofactors, which are involved in numerous metabolic pathways, such as fatty acid metabolism and energy metabolism. Studies have shown that rumen microbial flora can produce B vitamins required by ruminants, and supplementing B vitamins in the diet of lactating dairy cows can improve the lactation performance of dairy cows. However, there is currently a lack of systematic research on whether the changes in B vitamin levels caused by individual differences in dairy cows will affect their lactation performance, and the key B vitamins that can regulate the lactation phenotype of dairy cows have not been accurately identified. Which B vitamins can be used to predict the lactation performance of dairy cows needs further research. SUMMARY

[0004] The purpose of the present application is to make up for the shortcomings of the prior art, and to provide the application of pyridoxinic acid and / or pyridoxine in predicting the lactation performance of lactating dairy cows, which has the characteristics of high sensitivity and strong accuracy, and can accurately predict the lactation performance of dairy cows.

[0005] The present application provides the application of pyridoxinic acid and / or pyridoxine in predicting the lactation performance of dairy cows.

[0006] The present application also provides the application of pyridoxinic acid and / or pyridoxine in dairy cow breeding, which includes selecting dairy cows with high lactation performance.

[0007] The present application also provides the application of a reagent for detecting pyridoxinic acid and / or pyridoxine in preparing a product for predicting the lactation performance of dairy cows.

[0008] Preferably, the product includes a kit.

[0009] Preferably, the dairy cow includes a lactating dairy cow.

[0010] Preferably, the lactation performance comprises one or more of milk yield, milk protein yield, milk fat yield, lactose percentage, lactose yield and total solid yield.

[0011] The present application also provides a method for predicting the lactation performance of a dairy cow, detecting the content of pyridoxate and / or pyridoxal in serum of the dairy cow to be tested; The lactation performance comprises one or more of milk yield, milk protein yield, milk fat yield, lactose percentage, lactose yield and total solid yield. If the content of pyridoxate in serum of the dairy cow to be tested is > 8.96 ng / mL, the dairy cow to be tested is a high-yield milk cow; if the content of pyridoxate in serum of the dairy cow to be tested is > 9.35 ng / mL, the dairy cow to be tested is a high-yield milk protein cow; if the content of pyridoxate in serum of the dairy cow to be tested is > 9.02 ng / mL, the dairy cow to be tested is a high-yield milk fat cow; if the content of pyridoxate in serum of the dairy cow to be tested is > 8.99 ng / mL, the dairy cow to be tested is a high-lactose percentage cow; if the content of pyridoxate in serum of the dairy cow to be tested is > 8.79 ng / mL, the dairy cow to be tested is a high-lactose yield cow; if the content of pyridoxate in serum of the dairy cow to be tested is > 10.75 ng / mL, the dairy cow to be tested is a high-total solid yield cow. If the content of pyridoxal in serum of the dairy cow to be tested is > 2.68 ng / mL, the dairy cow to be tested is a high-yield milk cow; if the content of pyridoxal in serum of the dairy cow to be tested is < 1.23 ng / mL, the dairy cow to be tested is a high-yield milk protein cow; if the content of pyridoxal in serum of the dairy cow to be tested is < 1.55 ng / mL, the dairy cow to be tested is a high-yield milk fat cow; if the content of pyridoxal in serum of the dairy cow to be tested is > 2.52 ng / mL, the dairy cow to be tested is a high-lactose percentage cow; if the content of pyridoxal in serum of the dairy cow to be tested is > 1.93 ng / mL, the dairy cow to be tested is a high-lactose yield cow; if the content of pyridoxal in serum of the dairy cow to be tested is < 2.02 ng / mL, the dairy cow to be tested is a high-total solid yield cow.

[0012] The present application also provides a method for improving the lactation performance of a dairy cow, comprising: increasing the content of pyridoxate and / or pyridoxal in serum of the dairy cow.

[0013] Advantages: The present application is based on the correlation analysis between the content of B vitamins in serum of a dairy cow and the lactation performance of the dairy cow, and the results show that the content of pyridoxate and / or pyridoxal in serum is closely related to the lactation performance of the dairy cow, has high sensitivity and accuracy, and can be applied to the prediction of the lactation performance of a dairy cow, shortening the screening period of a low-yield cow herd, and reducing the economic loss in feed and labor caused by the traditional elimination procedure. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments.

[0015] Figure 1 Spearman correlation analysis results of serum B vitamin content and lactation performance of lactating cows; wherein, the horizontal axis is the serum B vitamin content, the vertical axis is the lactation performance of the cow, different colors represent different correlations, pink is positive correlation, blue is negative correlation, P <0.05, P <0.01. Figure 2 The multiple task LASSO regression model analysis results of the present application; wherein, the vertical coordinate is the serum factor belonging to B vitamins, different colors of columns represent different lactation traits, and the horizontal coordinate represents the corresponding LASSO coefficient; Figure 3 The ROC curve diagram of pyridoxal and pyridoxine for predicting the high and low milk yield of lactating cows; Figure 4 The ROC curve diagram of pyridoxal and pyridoxine for predicting the high and low milk protein yield of lactating cows; Figure 5 The ROC curve diagram of pyridoxal and pyridoxine for predicting the high and low milk fat yield of lactating cows; Figure 6 The ROC curve diagram of pyridoxal and pyridoxine for predicting the high and low lactose rate of lactating cows; Figure 7 The ROC curve diagram of pyridoxal and pyridoxine for predicting the high and low total solid content of lactating cows; Figure 8 The ROC curve diagram of pyridoxal and pyridoxine for predicting the high and low lactose yield of lactating cows. DETAILED DESCRIPTION

[0016] The present application provides the application of pyridoxal and / or pyridoxine in predicting the lactation performance of cows.

[0017] The present application also provides the application of pyridoxal and / or pyridoxine in cow breeding, which includes breeding cows with high lactation performance.

[0018] The present application also provides the application of reagents for detecting pyridoxal and / or pyridoxine in preparing products for predicting the lactation performance of cows.

[0019] As an embodiment, the product of the present application includes a kit.

[0020] As an embodiment, the cow of the present application includes a lactating cow. As an embodiment, the lactating cow of the present application includes a cow with 105-135 days of lactation period and 2-3 times of parity.

[0021] As an embodiment, the lactation performance of the present application includes one or more of milk yield, milk protein yield, milk fat yield, lactose rate, lactose yield and total solid yield; as an embodiment, the lactation performance of the present application includes milk yield, milk protein yield, milk fat yield, lactose rate, lactose yield and total solid yield. The present application detects the content of B vitamins in the serum of dairy cows, and carries out correlation analysis with the lactation performance of the dairy cows. It is found that the content of pyridoxate in the serum is significantly positively correlated with milk yield, milk protein yield, milk fat yield, lactose rate, lactose yield and total solid yield; the content of pyridoxal in the serum is significantly positively correlated with lactose rate, lactose yield and milk yield, and is significantly negatively correlated with milk protein yield, milk fat yield and total solid.

[0022] The present application also provides a method for predicting the lactation performance of dairy cows, detecting the content of pyridoxate and / or pyridoxal in the serum of the dairy cows to be tested; The lactation performance includes one or more of milk yield, milk protein yield, milk fat yield, lactose rate and total solid yield; If the content of pyridoxate in the serum of the dairy cow to be tested is >8.96 ng / mL, the dairy cow to be tested is a high milk yield dairy cow; if the content of pyridoxate in the serum of the dairy cow to be tested is >9.35 ng / mL, the dairy cow to be tested is a high milk protein yield dairy cow; if the content of pyridoxate in the serum of the dairy cow to be tested is >9.02 ng / mL, the dairy cow to be tested is a high milk fat yield dairy cow; if the content of pyridoxate in the serum of the dairy cow to be tested is >8.99 ng / mL, the dairy cow to be tested is a high lactose rate dairy cow; if the content of pyridoxate in the serum of the dairy cow to be tested is >8.79 ng / mL, the dairy cow to be tested is a high lactose yield dairy cow; if the content of pyridoxate in the serum of the dairy cow to be tested is >10.75 ng / mL, the dairy cow to be tested is a high total solid yield dairy cow; If the content of pyridoxal in the serum of the dairy cow to be tested is >2.68 ng / mL, the dairy cow to be tested is a high milk yield dairy cow; if the content of pyridoxal in the serum of the dairy cow to be tested is <1.23 ng / mL, the dairy cow to be tested is a high milk protein yield dairy cow; if the content of pyridoxal in the serum of the dairy cow to be tested is <1.55 ng / mL, the dairy cow to be tested is a high milk fat yield dairy cow; if the content of pyridoxal in the serum of the dairy cow to be tested is >2.52 ng / mL, the dairy cow to be tested is a high lactose rate dairy cow; if the content of pyridoxal in the serum of the dairy cow to be tested is >1.93 ng / mL, the dairy cow to be tested is a high lactose yield dairy cow; if the content of pyridoxal in the serum of the dairy cow to be tested is <2.02 ng / mL, the dairy cow to be tested is a high total solid yield dairy cow.

[0023] The application also provides a method for improving the lactation performance of a dairy cow, comprising: increasing the content of pyridoxal and / or pyridoxic acid in the serum of the dairy cow. The application does not have strict requirements for the method for increasing the content of pyridoxal and / or pyridoxic acid in the serum of the dairy cow, and a conventional method in the art can be used, for example, pyridoxal and / or pyridoxic acid can be supplemented into the feed of the dairy cow.

[0024] In order to further illustrate the application, the application of pyridoxal and / or pyridoxic acid provided by the application in predicting the lactation performance of a lactating dairy cow is described in detail below in combination with the accompanying drawings and examples, but they should not be understood as limiting the protection scope of the application.

[0025] Example 1 1. Test dairy cow: 100 Holstein dairy cows in the lactation period of 105-135 days and having 2-3 births, selected from Shandong Huamao Dadi Ranch.

[0026] Inclusion criteria: Holstein dairy cows in the lactation period in the ranch were selected, and the dairy cows should meet the following basic requirements: ① good physical development, normal body condition, and healthy in clinical examination; ② excluding genetic diseases and infectious diseases; ③ completing immunization and deworming work one month before sampling; ④ trying to ensure that the cattle are docile and have small stress responses; ⑤ the cattle should be in the lactation period of 105-135 days at the time of sampling; ⑥ the cattle should be in the 2-3 births.

[0027] 2. Test method 2.1. Collection of blood samples: 10 mL of tail root venous blood of the test dairy cow was collected in a vacuum blood collection tube without anticoagulant, and the cow number was marked. Immediately after collection, it was placed in a light-proof box and stored at 4°C; 2.2. Collection of serum samples: 4°C for 1h, centrifuged at 3500g / min for 15min, and the upper serum was taken and placed in a 1.5mL cryogenic tube, marked with the cow number, and stored in liquid nitrogen for further analysis; 2.3. Detection of serum B vitamins: 45 serum samples of the test dairy cows were randomly selected from the serum samples of the test dairy cows, and the detection of B vitamins was carried out by liquid chromatography-mass spectrometry (LC-MS / MS), and the specific detection method was as follows: (1) Take the serum sample to be detected and place it at 4°C for thawing. (2) Take 50μL of the sample / standard into a 1.5mL centrifuge tube, add 150µL of solvent B, and shake for 10min. (3) Place the centrifuge tube in a low-temperature centrifuge, centrifuge at 4°C, 12000rpm for 10min. (4) Take 100μL of supernatant, add 100μL of solvent A, and vortex to mix. (5) Place in a 2mL sample vial, with a 250μL inner liner tube, and wait for testing. (6) Target data processing: TargetLynx quantitative software is used for target data peak area calculation, and the retention time error is allowed to be 15s. The concentration calculation uses the standard curve method to obtain the quantitative result.

[0028] Solvent A: water containing 100 pg / mL ascorbic acid and 100 pg / mL citric acid; Solvent B: methanol containing 100 pg / mL ascorbic acid, 100 pg / mL citric acid, 5 ng / mL nicotinamide-d4, 5 ng / mL VB5-13C315N and 5 ng / mL pyridoxal-d3; Standard and sample for preparing standard curve: Standard solution: each vitamin standard was dissolved in solvent A to prepare a stock solution with a concentration of 1 mg / mL. A standard mixture was then prepared, with the concentration of each analyte being 100 pg / mL.

[0029] Sample solution for preparing standard curve: the standard solution was diluted with solvent A in a stepwise manner, with the concentration of each vitamin standard being 0.4, 0.8, 1.6, 4, 8, 16, 40, 80, 400, 800, 4000 ng / mL.

[0030] Chromatographic conditions: Waters ACQUITY UPLC I-CLASS ultra-high performance liquid chromatography was used for chromatographic separation, with the following conditions: Chromatographic column: Waters UPLC HSS T3 (2.1 mm (inner diameter of chromatographic column) x 100 mm (length of chromatographic column), particle size 1.8 pm).

[0031] Mobile phase A: water containing 0.1% acetic acid and 10 mM ammonium acetate; Mobile phase B: methanol; Elution gradient: 0.0 min: 99% v / v mobile phase A, 1% v / v mobile phase B; 1.0 min: 99% v / v mobile phase A, 1% v / v mobile phase B; 4 min: 50% v / v mobile phase A, 50% v / v mobile phase B; 4.5 min: 100% v / v mobile phase B; 5.5 min: 100% v / v mobile phase B; 5.6 min: 99% v / v mobile phase A, 1% v / v mobile phase B; 7.0 min: 99% v / v mobile phase A, 1% v / v mobile phase B.

[0032] Mass spectrometric conditions: Waters XEVO TQ-XS tandem quadrupole mass spectrometry system was used for mass spectrometric analysis. Positive ion scanning, ion source voltage 3 KV, cone hole voltage 30 V, cone hole gas flow rate 150 L / h, desolvation temperature 500 °C, desolvation flow rate 1000 L / Hr.

[0033] 2.4. Milk sample collection and milk component determination Milk yield was recorded by DeLaval automatic milking system. Milk samples were collected in the morning, noon and evening, mixed in the ratio of 4:3:3, and 50 mL was taken for analysis. Potassium dichromate was added to the sample as a preservative, and the milk composition was determined using a fully automatic milk composition analyzer.

[0034] 2.5. Constructing the prediction model of dairy cow lactation performance The B vitamins content in serum of lactating dairy cows and the results of lactation performance in step 2.3 were statistically analyzed by Excel software. Spearman correlation analysis was performed on the B vitamins content in serum and lactation performance using R language. When |R| > 0.3, P <0.05, the difference was considered statistically significant. The results showed that the content of pyridoxine acid in serum had a significant positive correlation with lactose yield, milk fat yield, milk protein yield, milk yield, urea nitrogen and total solid yield; the content of pyridoxal in serum had a significant positive correlation with lactose rate, lactose yield and milk yield. The content of pyridoxal in serum had a significant negative correlation with milk protein and total solid Figure 1 ).

[0035] 2.6. In order to test the ability of B vitamins content in serum to predict the lactation performance of dairy cows, a multi-task LASSO regression model was established. The larger the absolute value of the coefficient, the stronger the prediction weight of the serum factor on the trait. The coefficient of 0 indicates that LASSO considers that the prediction value of this serum factor on the trait is insufficient. The results showed that the lactation performance had non-zero coefficients on pyridoxine acid and pyridoxal; pyridoxine acid had positive values for lactose rate, milk protein yield, milk fat yield, lactose yield, milk yield and total solid, which were positively correlated, and the prediction weight of pyridoxine acid on milk yield was the strongest; pyridoxal had positive values for lactose yield, lactose rate and milk yield, which were positively correlated, and negative values for milk protein yield, milk fat yield and total solid, which were negatively correlated, and the prediction weight of pyridoxal on milk yield was the strongest Figure 2 ).

[0036] 2.7. In order to evaluate the pyridoxate and pyridoxal content to predict the lactation performance of Holstein cows, according to the yield, milk protein yield, milk fat yield, milk lactose rate, milk lactose yield and total solid, the top 15 of milk yield, milk protein yield, milk fat yield, milk lactose rate, milk lactose yield and total solid were set as high milk yield group, high milk protein yield group, high milk fat yield group, high milk lactose rate group, high milk lactose yield group and high total solid group, and the last 15 of milk yield, milk protein yield, milk fat yield, milk lactose rate, milk lactose yield and total solid were set as low milk yield group, low milk protein yield group, low milk fat yield group, low milk lactose rate group, low milk lactose yield group and low total solid group. ROC curve was drawn, and the best cut-off value was determined by Youden index, and the sensitivity, specificity and accuracy were calculated, and the results are shown in Table 1 and Figures 3-8

[0037] Table 1. Results of ROC curve analysis of subjects

[0038] According to Table 1 and Figure 3 It can be seen that the cut-off value of pyridoxate for predicting high and low milk yield is 8.96 ng / mL, AUC is 0.73, sensitivity is 93%, specificity is 53%, and accuracy is 73%. The cut-off value of pyridoxal for predicting high and low milk yield is 2.68 ng / mL, AUC is 0.69, sensitivity is 40%, specificity is 100%, and accuracy is 70%. The serum pyridoxate of Holstein lactating cows has high prediction value for high and low milk yield, and the serum pyridoxal of Holstein lactating cows has good prediction value for high and low milk yield.

[0039] According to Table 1 and Figure 4 It can be seen that the cut-off value of pyridoxate for predicting high and low milk protein yield is 9.35 ng / mL, AUC is 0.72, sensitivity is 73%, specificity is 67%, and accuracy is 70%. The cut-off value of pyridoxal for predicting high and low milk protein yield is 1.23 ng / mL, AUC is 0.56, sensitivity is 0.26%, specificity is 0.93%, and accuracy is 60%. The serum pyridoxate of Holstein cows has high prediction value for high and low milk protein yield; the serum pyridoxal of Holstein cows has certain prediction value for high and low milk protein yield.

[0040] According to Table 1 and Figure 5 ​It can be seen that the cut-off value of pyridoxic acid in predicting high and low milk fat yield of cows is 9.02 ng / mL, AUC is 0.76, sensitivity is 80%, specificity is 60%, and accuracy is 70%. The cut-off value of pyridoxal in predicting high and low milk fat yield of cows is 1.55 ng / mL, AUC is 0.60, sensitivity is 73%, specificity is 53%, and accuracy is 63%. It can be seen that the serum pyridoxic acid of Holstein cows has high prediction value for high and low milk fat yield; the serum pyridoxal of Holstein cows has good prediction value for high and low milk fat yield.

[0041] According to Table 1 and Figure 6 It can be seen that the cut-off value of pyridoxic acid in predicting high and low milk fat yield of cows is 9.02 ng / mL, AUC is 0.76, sensitivity is 80%, specificity is 60%, and accuracy is 70%. The cut-off value of pyridoxal in predicting high and low milk fat yield of cows is 1.55 ng / mL, AUC is 0.60, sensitivity is 73%, specificity is 53%, and accuracy is 63%. It can be seen that the serum pyridoxic acid of Holstein cows has high prediction value for high and low milk fat yield; the serum pyridoxal of Holstein cows has good prediction value for high and low milk fat yield.

[0042] According to Table 1 and Figure 7 It can be seen that the cut-off value of pyridoxic acid in predicting high and low milk fat yield of cows is 9.02 ng / mL, AUC is 0.76, sensitivity is 80%, specificity is 60%, and accuracy is 70%. The cut-off value of pyridoxal in predicting high and low milk fat yield of cows is 1.55 ng / mL, AUC is 0.60, sensitivity is 73%, specificity is 53%, and accuracy is 63%. It can be seen that the serum pyridoxic acid of Holstein cows has high prediction value for high and low milk fat yield; the serum pyridoxal of Holstein cows has good prediction value for high and low milk fat yield.

[0043] According to Table 1 and Figure 8 It can be seen that the cut-off value of pyridoxic acid in predicting high and low milk fat yield of cows is 9.02 ng / mL, AUC is 0.76, sensitivity is 80%, specificity is 60%, and accuracy is 70%. The cut-off value of pyridoxal in predicting high and low milk fat yield of cows is 1.55 ng / mL, AUC is 0.60, sensitivity is 73%, specificity is 53%, and accuracy is 63%. It can be seen that the serum pyridoxic acid of Holstein cows has high prediction value for high and low milk fat yield; the serum pyridoxal of Holstein cows has good prediction value for high and low milk fat yield.

[0044] According to the above, it can be seen that pyridoxinic acid and / or pyridoxine can accurately predict the lactation performance of dairy cows, has high sensitivity and strong accuracy, can be applied to shorten the screening period of low-yield cow group, and reduce the economic loss in feed and labor caused by traditional elimination process.

[0045] Although the above embodiments have made a detailed description of the present application, it is only a part of the embodiments of the present application, not all the embodiments, and other embodiments can be obtained according to the present embodiments without creativity, which belong to the protection scope of the present application.

Claims

1. Application of pyridoxic acid and / or pyridoxal in predicting lactation performance in dairy cows.

2. Use of pyridoxic acid and / or pyridoxal in dairy cow breeding, wherein the dairy cow breeding comprises breeding dairy cows with high lactation performance.

3. Use of reagents for detecting pyridoxic acid and / or pyridoxal in the preparation of products for predicting the lactation performance of dairy cows.

4. The use according to claim 3, characterized in that The products include kits.

5. The use according to any one of claims 1 to 4, characterized in that The dairy cows include lactating dairy cows.

6. The use according to any one of claims 1 to 4, characterized in that The lactation performance includes one or more of milk yield, milk protein yield, milk fat yield, lactose rate, lactose yield and total solids yield.

7. A method for predicting the lactation performance of dairy cows, characterized in that: Detecting the pyridoxic acid content and / or pyridoxal content in the serum of the dairy cow to be tested; The lactation performance includes one or more of milk yield, milk protein yield, milk fat yield, lactose rate, lactose yield and total solid yield; If the pyridoxalic acid content in the serum of the cow to be tested is greater than 8.96 ng / mL, the cow to be tested is a high milk production cow; if the pyridoxalic acid content in the serum of the cow to be tested is greater than 9.35 ng / mL, the cow to be tested is a high milk protein production cow; if the pyridoxalic acid content in the serum of the cow to be tested is greater than 9.02 ng / mL, the cow to be tested is a high milk fat production cow; if the pyridoxalic acid content in the serum of the cow to be tested is greater than 8.99 ng / mL, the cow to be tested is a high lactose rate cow; if the pyridoxalic acid content in the serum of the cow to be tested is greater than 8.79 ng / mL, the cow to be tested is a high lactose production cow; if the pyridoxalic acid content in the serum of the cow to be tested is greater than 10.75 ng / mL, the cow to be tested is a high total solid production cow; If the pyridoxal content in the serum of the cow to be tested is >2.68 ng / mL, the cow to be tested is a high milk production cow; if the pyridoxal content in the serum of the cow to be tested is <1.23 ng / mL, the cow to be tested is a high milk protein production cow; if the pyridoxal content in the serum of the cow to be tested is <1.55 ng / mL, the cow to be tested is a high milk fat production cow; if the pyridoxal content in the serum of the cow to be tested is >2.52 ng / mL, the cow to be tested is a high lactose rate cow; if the pyridoxal content in the serum of the cow to be tested is >1.93 ng / mL, the cow to be tested is a high lactose production cow; if the pyridoxal content in the serum of the cow to be tested is <2.02 ng / mL, the cow to be tested is a high total solid production cow.

8. A method for improving the lactation performance of dairy cows, characterized in that: include: Increase the content of pyridoxic acid and / or pyridoxal in dairy cow serum.

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