To investigate the effects of Astragalus polysaccharides on production performance, antioxidant capacity and immune function of dairy cows, and to provide theoretical basis for improving dairy cattle breeding efficiency and health management.

Seventy-two cows with similar first litter, milk production and body condition were selected and randomly divided into four groups: control group (CON), low-dose group (APS 1.5), medium-dose group (APS 3.0) and high-dose group (APS 4.5).The control group was fed the basal diet, and the other three groups were fed the basal diet supplemented with 1.5, 3.0, and 4.5 g/kg Astragalus polysaccharide, respectively.The pre-experimental period lasted 15 d, and the formal experimental period lasted 60 d.during which milk production, milk composition, antioxidant indicators and immune indicators were monitored and analyzed.

Milk production in the APS 3.0 group was significantly improved, milk protein rate, milk fat rate and dry matter content were improved, and somatic cell number was significantly reduced; serum total antioxidant capacity (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities were significantly increased, and malondialdehyde (MDA) content was significantly reduced in each experiment group; The immunoglobulin IgA and IgM contents in the astragalus polysaccharide-supplemented groups were significantly increased, while the tumor necrosis factor-α (TNF-α) content was significantly decreased, with the medium-dose group showing the optimal effect.

Astragalus polysaccharide cansignificantly improve the production performance of dairy cows, enhance antioxidant capacity and immune function, among which 3.0 g/kg addition has the best effect and has high application value in breeding.

This study aimed to explore integrated prevention and control strategies for necrobacillosis in sheep using a combination of Traditional Chinese Medicine (TCM) and western medicine.

Based on the etiology, epidemiology, and clinical manifestations of the disease, TCM theory was applied to attribute it to internal invasion of damp-heat toxins and stagnation of qi and blood.The treatment principles included clearing heat and detoxifying, promoting blood circulation, removing stasis, and eliminating necrotic tissue to promote granulation.This integrated approach combined precise pathogen control from western medicine with holistic regulation and green therapies of TCM.

A multi-dimensional prevention and control system was established, emphasizing "prevention over treatment, integration of rearing and prevention, and combined application of Chinese and western medicine," which provided more effective, safe, and sustainable solutions for clinical practice.

The integrated strategy addresses the limitations of conventional western methods (e.g., antibiotic resistance, drug residues) and contributes significantly to the healthy development of the sheep industry.

Combination of traditional Chinese and western medicine: western medicine can resist secondary infection and treat local symptoms, while traditional Chinese medicine has broad-spectrum antivirus, overall conditioning and promote tissue regeneration.

Western medicine therapy takes effect quickly but the overall adjustment is weak, while Chinese medicine therapy emphasizes the overall adjustment but takes effect relatively slowly.The combination of the two can complement each other, accelerate rehabilitation, reduce recurrence and reduce the use of antibiotics.

The organic combination of traditional Chinese and western medicine can synergize and improve the cure rate, which is an effective way to prevent and control the disease.

To establish and evaluate a real-time fluorescent quantitative PCR (qPCR) method for detecting Salmonella paratyphi B in dairy products.

Specific invA gene of Salmonella paratyphi B was used as the target to design primers. After optimizing the qPCR reaction system and conditions with SYBR GreenⅠ dye, amplification was performed on gradient diluted plasmid standards to establish a standard curve. The sensitivity, specificity and repeatability of the method were systematically verified, and the detection performance was compared with the traditional culture method.

The standard curve equation was y=-3.186 6 +13.172, with a correlation coefficient (R²) of 0.9949. The amplification efficiency (E%) was 105.9%. The linear relationship was good. The qPCR method for detecting Salmonella paratyphi B had a sensitivity of 17.9 copies/μL. In the specificity verification, only Salmonella paratyphi B showed positive amplification, while Escherichia coli, Staphylococcus aureus, etc. were negative. There was no cross-reaction. The repeatability test showed that the intra-group coefficient of variation was 0.2%~0.69%, and the inter-group coefficient of variation was 0.49%~1.54%, all of which were less than 3%, indicating excellent stability. Compared with the traditional culture method (requiring 5~7 days), this qPCR method can shorten the detection time to within 6 hours, significantly improving the detection efficiency.

The SYBR Green Ⅰ qPCR method established in this study has the advantages of high sensitivity, strong specificity, good repeatability, simple operation and rapid detection, providing reliable technical support for the rapid screening, precise quantification and food safety risk prevention and control of Salmonella paratyphi B in dairy products.

This study aimed to conduct an optimization research on improving the recovery rate when determining benzoic acid and sorbic acid in fermented milk using the first method (iquid chromatography) as stipulated in "GB 5009.28—2016 Food Safety National Standard Determination of Benzoic Acid, Sorbic Acid and Saccharin Sodium in Food".

By improving the pre-treatment method for extracting fermented milk samples, the sample was weighed into a 50 mL conical centrifugal tube instead of a 50 mL volumetric flask, and then ultrasonic extraction was performed. The recovery rates of the target analytes before and after optimization were compared.

After optimization, the recovery rate of the target analytes were significantly improved, with an average increase of 3.80% to 6.09%, and the repeatability test results met the requirements.

When using the national standard method for sample pre-treatment, after weighing the samples in a centrifuge tube and conducting ultrasonic extraction, a precipitant needs to be added for centrifugation before transferring the sample to a volumetric flasks.It is worth noting that the final volume of dilution was not included in the experiment, as it did not account for the 2 mL of ferrocyanide potassium solution and 2 mL of zinc acetate solution added. The theoretical final dilution volume should be 54 mL, but the actual calculation formula used a volume of 50 mL, which will result in a lower recovery rate result. After optimization in this study, the samples were directly weighed into a 50 mL volumetric flask, and all the pre-treatment steps were carried out in the flask. The final volume of the solution was precisely controlled at 50 mL. At the same time, in the actual calculation formula, the volume used was also 50 mL. The detection recovery rate obtained by this method was close to the theoretical value, demonstrating high accuracy and good repeatability.

To investigate the effect of stirring process in dairy product processing on the dissolved oxygen content of milk.

During the dairy processing, the dissolved oxygen content of milk directly affects the quality of the final product. Different liquid levels and stirring speeds in the tanks may result in variations in the dissolved oxygen content. This study focused on milk samples from the high, medium, and low liquid levels of the raw milk storage tank and the filling buffer tank, and measured and compared the dissolved oxygen content in the sample under different stirring rates.

During milk storage, if the rotational speed remains constant in the raw milk storage tank, the dissolved oxygen content of milk at the high liquid level is (8.74±0.18) ppm, at the medium liquid level is (9.10±0.13) ppm, and at the low liquid level is (9.55±0.42) ppm. The dissolved oxygen content significantly increases as the liquid level decreases; if the rotational speed decreases as the liquid level decreases in the filling buffer tank, the dissolved oxygen content at the high liquid level is (8.81±0.11) ppm, at the medium liquid level is (8.80±0.17) ppm, and at the low liquid level is (8.79±0.13) ppm. There is no significant change in the dissolved oxygen content as the liquid level decreases.

The data from this experiment can provide a theoretical foundations and practical guidance for optimizing the production of dairy products to reduce dissolved oxygen content.