[Objective] By analyzing four body weights（BW,kg）in four phases of heifers'; life and milk production data from 2014 to 2024.The first objective was to analyze the changes of BW and average daily gain（ADG,kg/d） over the past decade,while the second was to examine the relationship between BW and ADG,as well as their correlation with primiparous milk yield. [Method] ADG calculation method 1：（weight at a designated phase-birth weight）÷age of days;ADG calculation method 2：（weight at designated phase-weight at previous phase）÷（weighing date at designated phase-weighing date at previous phase）,analyzed heifers'; growth and development status and their primiparous milking performance. [Result]（1）Weaning ADG increased from 0.80 kg/d in 2015 to 0.88 kg/d in 2023,first calving BW had increased,while the age at first calving had decreased.（2）There were significant differences in ADG at each phase.Weaning ADG ranged from 0.85 to 1.00 kg/d,maximum ADG was 0.95~1.10 kg/d which during transfer phase,first breeding ADG was 0.86~0.96 kg/d,and minimum ADG was 0.75~0.83 kg/d during first calving.（3）The larger first calving BW,the higher 305-d milk yield and peak milk yield.However,most cows'; first calving BW was concentrated in （550,600]kg（Group A） and （600,650]kg（Group B）（accounted for 70.5%,48.6% of them at the age of 660 d to 690 d）.（4）There was no significant difference in BW and ADG between Group A and Group B at weaning phase,but during the transfer and first breeding phase,the differences in BW gradually widened.First calving BW of Group B was about 45 kg higher than Group A';s.With the age increases,the difference in ADG between Group A and Group B became increasingly evident.First calving ADG of Group B was 0.06 kg/d higher than Group A's.（5）At the age of 660~690 d（22~23 m）,305-d milk yield of Group B was approximately 360 kg higher than Group A's,peak milk yield of Group B was approximately 1.3 kg higher;305-d milk yield of Group B was approximately 848 kg higher than Group C（500,550]kg,peak milk yield of Group B was approximately 3.3 kg higher. [Conclusion] To achieve first calving BW 600~650 kg（pre-calving BW 640~690 kg） for heifer at the age of 22~24 m,farm managers need to regularly monitor heifers'; BW and evaluate the diet to monitor their growth status and balance the relationships between age and BW.This will provide sufficient nutrient intake for heifer,to ensure maximizing their production potential under optimal developmental conditions.

[Objective] This study aimed to systematically analyze key performance indicators of large-scale dairy farms in Hebei Province to provide scientific evidence for improving farm management and economic efficiency. [Method] Using an intelligent farm management system,production data from 118,143 dairy cows across 17 large-scale farms in Hebei Province from 2021 to 2024 were collected. Key indicators,including herd structure,milk production performance,health management,and feeding efficiency,were analyzed and compared with the average values from 352 farms within the system and industry standards. [Result] The results showed that in 2024,the 305-day corrected milk yield of the sampled farms reached 10,673 kg,significantly higher than the system average by 10.47% （p< 0.05）. The incidence rates of clinical mastitis （16.1%） and hoof diseases （10.1%） in mature cows were lower than the industry average,while postpartum metabolic disorders （e.g.,ketosis： 3.3%） and reproductive diseases （e.g.,retained placenta： 8.5%） showed a significant upward trend （p< 0.05）. Adjustments in farm management strategies were evident,with an annual culling rate of mature cows at 43.7%,of which proactive culling accounted for 41.1%. The rearing of replacement heifers achieved notable results,with daily weight gains at all stages exceeding national standards. However,the incidence rates of calf diarrhea （17.8%） and pneumonia （11.6%） remained higher than recommended industry levels. [Conclusion] Intelligent dairy farms in Hebei Province have achieved significant progress in milk production performance and health management,but management disparities among farms have led to considerable variations in key indicators. To further enhance production efficiency and management standards,it is recommended to optimize herd structure,strengthen genetic improvement,improve disease prevention and control systems,establish scientific culling mechanisms,and implement standardized rearing protocols for replacement heifers.

[Objective] To analyze the effects of dietary supplementation with dandelion extract on the growth performance,lactation performance and immune indicators of dairy cows. [Method] A total of 160 dairy cows with similar body weight and parity were selected as the research objects in a large-scale dairy farm in Shan County. They were randomly divided into 4 groups by the random number table method,with 5 replicates in each group and 8 cows in each replicate. They were the control group,the low-dose group,the medium-dose group and the high-dose group respectively. The control group was fed with the basal diet,while the low-dose group,medium-dose group and high-dose group were respectively supplemented with 0.2%,0.4% and 0.6% dandelion extract on the basis of feeding the basal diet. The experimental period was 50 days. After the experiment,the growth performance,lactation performance and immune indicators of each group were analyzed. [Result] The average daily feed intake and average daily weight gain of dairy cows in the low-dose group,medium-dose group and high-dose group were significantly higher than those in the control group（P< 0.05）,and the feed conversion ratio of dairy cows in the medium-dose group was significantly lower than that in the control group（P< 0.05）. The indicators of milk production、milk protein rate、lactose rate of dairy cows in the low-dose group,medium-dose group and high-dose group were significantly higher than those in the control group（P< 0.05）,while the indicators of somatic cell number and milk urea nitrogen were significantly lower than those in the control group（P< 0.05）. The contents of IgM,IgG and IL-10 in dairy cows in the low-dose group,medium-dose group and high-dose group were significantly higher than those in the control group（P< 0.05）,and TNF-α was significantly lower than that in the control group（P< 0.05）. [Conclusion] Under the conditions of this experiment, the optimal dosage of dandelion extract in the diet was determined to be 0.4%. Dietary supplementation with dandelion extract can promote the growth of dairy cows, improve lactation performance,and enhance immune function,providing a scientific basis for the rational use of natural additives in dairy farming.

[Objective] To investigate the therapeutic efficacy of ceftiofur crystalline injection in treating bovine respiratory diseases. [Method] Fifty cattle with respiratory diseases from a farm in Pingdu City were selected as experimental animals and randomly divided into a control group and a test group. The control group was treated with a cough-relief injection,while the test group received ceftiofur crystalline injection. [Result] After treatment,the clinical score of the test group was significantly lower than that of the control group [(0.13±0.14) points vs. (0.66±0.21) points,P< 0.05]. Significant differences were observed in clinical biochemical indicators such as ALP,AST,ALT,GLU,TCH,and BUN between the two groups (P< 0.05),while the TP value showed no significant difference [(68.13±5.73) g/L vs. (67.82±5.54) g/L,P> 0.05]. The clinical treatment efficacy rate in the ceftiofur crystalline injection test group was significantly higher than that in the control group [(92.00% vs. 76.00%),P< 0.05]. Adverse reactions occurred in 4 cattle in the control group,with a significantly higher incidence rate compared to the test group (P< 0.05). [Conclusion] Ceftiofur crystalline injection demonstrates significant clinical efficacy in treating bovine respiratory diseases with no apparent adverse reactions,providing a reference for the development of scientific and rational clinical treatment protocols in veterinary husbandry.

[Objective] In order to investigate the influence of Chinese medicine compound formula on the treatment effect and fertility rate of cows with retained placenta. [Method] This experiment investigated the prevalence of retained placenta in postpartum cows in a dairy farm in Tianjin,and used different treatments for the treatment. [Result] By observing clinical symptoms and vaginal examination,a total of 40 postpartum cows were diagnosed with retained placenta among 245 postpartum cows in the farm,of which the incidence rate of primiparous cows was 20.00%,that of second-parous cows was 14.71%,that of third-parous cows was 13.92%,that of fourth-parous cows was 18.42%,and the total incidence rate of cows was 16.33%;by means of different treatment methods,the cure rate was 33.33% in the control group,85.71% in the Chinese medicine compound treatment group,and 92.86% in the antibiotic treatment group; the oestrus rate was the lowest in the control group,33.33%,the highest in the Chinese medicine compound treatment group,92.86%,and the second highest in the antibiotic treatment group,85.71%; the fertility rate was 25.00% in the control group,85.71% in the Chinese medicine compound treatment group,and 71.43% in the antibiotic treatment group. [Conclusion] Chinese medicine compound can effectively treat postpartum retained placenta in dairy cows,and the therapeutic effect is similar to that of antibiotic treatment,and it can effectively improve the estrus rate and fertility rate of cows with retained placenta.

In recent years,with the expansion of dairy goat farming scale,the incidence of streptococcosis has increased significantly,causing severe economic losses to the industry. Based on etiological analysis and prevention practices,this study systematically investigated the pathogenic characteristics, epidemiological patterns, and diagnostic methods of streptococcosis in dairy goats. The results indicate that the disease is primarily caused by β-hemolytic Streptococcus （S. equi subsp. zooepidemicus）, with a high incidence during winter and spring, and clinical manifestations including high fever, joint swelling, and visceral lesions. Laboratory diagnostics （e.g.,PCR）enable accurate pathogen detection. For prevention and control, a strategy of prevention-first, integrated management was proposed, including improved feeding practices, regular immunization （recommending streptococcal vaccines in winter and spring）,scientific medication （e.g.,penicillin combined with traditional Chinese medicine）,and the establishment of an epidemic monitoring system. Practical applications demonstrated that comprehensive implementation of these measures reduced the incidence rate by 30%,significantly mitigating farming losses. This study provided theoretical and practical insights for the scientific prevention and control of streptococcosis in dairy goats,contributing to the sustainable development of the dairy goat industry.

Infant formula food is a key source of nutrition intake for infants and young children when breast milk is insufficient. This paper systematically reviewed the revision trends of major standard systems such as the Codex Alimentarius Commission（CAC）,the European Union,Australia, New Zealand and China,with a focus on comparing and analyzing the differences in nutritional components（energy,protein,DHA,etc.）and safety indicators（pollutants,microorganisms,etc.）of formula foods for infants （0~6 months old）,older infants （6~12 months old）and young children（12~36 months old）. Research has found that there are differences in the limit standards for nutrients,heavy metals and pollutants,etc. for infant formula food among countries. The practice of the European Union in dynamically adjusting pesticide residue limits using the risk threshold models is of considerable reference value. Based on this,it is recommended to establish a dual-track mechanism of dynamic adaptation of nutrients-forward-looking monitoring of pollutants which not only promotes the alignment of relevant standards in China with international standards,but also fully considers local practical needs,so as to more accurately and effectively meet the nutritional needs of infants and young children,and build a solid guarantee for food safety and nutritional supply for infants and young children.

During the high-temperature sterilization process of dairy products,although most microorganisms are inactivated,some thermoduric bacteria still survive,posing a serious threat to the quality and sensory quality of sterilized milk. This paper investigate the impact of thermoduric bacteria on dairy product quality by analyzing the physiological and biochemical characteristics of different types of thermoduric bacteria and the formation mechanisms of their biofilms.The inactivation conditions and sterilization methods of thermoduric bacteria were elaborated in detail. The control measures of thermoduric bacteria in dairy products from the source to the processing process were discussed from the perspective of pastures and dairy processing factories,which provided data support for pastures and dairy enterprises to formulate effective thermoduric bacteria inactivation strategies.

Goat milk possesses high nutritional value with its composition being close to that of human breast milk. It is rich in milk proteins,milk fat,lactose,minerals and other nutrients. Its fat globules are small,with short fatty acid carbon chains and low αs1-casein content,resulting in fewer allergic reactions in humans. Currently,most of China's goat milk is used to produce milk powder,while a small portion is utilized for liquid milk,fermented milk,cheese and other products. This paper analyzed the nutritional components of goat milk,systematically reviewed the key technical challenges and solutions in the diversified development of products such as milk powder,fermented milk and cheese,and provided an outlook on the future development direction of the goat milk industry.

Probiotics,mainly lactic acid bacteria（LAB）,play a key role in the research and development of functional dairy products.They can regulate the intestines and improve intestinal related diseases.Their potential functions include competing for adhesion sites,producing bactericides,improving intestinal permeability,releasing active metabolites,regulating immunity and stimulating cellular protective responses,etc.This review mainly introduced the efficacy and mechanism of action of probiotics in functional dairy products,and analyzed the possible difficulties and challenges in their application,providing a reference for the development and application of functional dairy products.