As a novel-type of safe and green feed additives, microecological preparations have been widely used in animal husbandry production. The research progress on the application of microecological preparations in livestock and poultry farming industry is reviewed, and the application potential of Parabacteroides as the next generation of new probiotic additive in animal husbandry is expounded, in hoping to provide insights into the research and development of new microecological preparations for livestock and poultry.

In the context of global climate change, extreme drought has been proven to pose significant impacts on the structure and function of ecosystems, especially on soil and vegetation characteristics. However, the impact level of extreme drought on ecosystems largely varied due to the ecosystem types. The grassland ecosystem is the largest terrestrial ecosystem in China, undertaking the prominent responsibility of economic and ecological sustainable development in pastoral areas. It is highly vulnerable to changes in precipitation patterns. Therefore, assessing the response of grassland soil and vegetation characteristics to extreme drought is of great significance for understanding the evolution laws of natural ecosystems, as well as preventing and reducing the losses resulting from future extreme climate events in the ecological environment and economic development. This paper reviews the research progress on the response of grassland ecosystems to extreme drought in the aspects of soil moisture, temperature, nutrients, mineralization and microorganisms, as well as vegetation community characteristics, vegetation phenology and functional traits, in hoping to provide references for investigating the selection and adaptation of grassland ecosystems to extreme drought climate under global climate change conditions.

Silent information regulator 2-related enzyme 3 （SIRT3）, a member of nicotinamide adenine dinucleotide （NAD⁺）-dependent histone deacetylase family, gets involved and plays important roles in energy metabolism, oxidative stress and apoptosis. Its regulatory roles are closely associated with the occurrence of several diseases. This paper reviews the regulatory mechanisms of downstream transcription factors of SIRT3 such as AMP-activated protein kinase （AMPK）, mitochondrial permeability transition pore （mPTP） and nuclear factor-κB （NF-κB）, as well as the roles of SIRT3 in cardiovascular diseases, tumors and diabetes mellitus, in hoping to provide references for the prevention and treatment of related diseases.

[Objective] This study was conducted to investigate the differences and changing characteristics of nutrient contents of soil and vegetation in typical grasslands in Inner Mongolia at different periods, and to provide references for the rational utilization of typical grasslands, the restoration and management of degraded grasslands, and the sustainable development of animal husbandry in Inner Mongolia. [Method] A total of eight monitoring points were selected from the typical grasslands in different regions of Inner Mongolia, including G1 （Ewenki Grassland, temperate meadow grassland, Hulun Buir City）, G2 （Urad Grassland, desert grassland, Bayannur City）, G3 （natural grassland, Ulanqab City）, G4 （Huitengxile Grassland, tessellated meadow grassland, Ulanqab City）, G5 （Horqin Grassland, temperate meadow grassland, Tongliao City）, G6 （artificial forage planting site, Chifeng City）, G7 （Urad Grassland, desert grassland, Baotou City), and G8 （Gegentala Grassland, desert grassland, Ulanqab City）. In the year of 2020, the soil samples of 0-20 cm soil layers and the above-ground parts of plant samples were taken at different monitoring points during the re-greening, vigorous and withering periods of forage, respectively. The contents of the conventional nutrients in the soil and plant samples were determined. The comprehensive scores of soil and vegetation nutrient levels at different monitoring points at different periods were calculated and sorted by using the principal component analysis method. [Result] The content of soil total nitrogen （STN） in G4 monitoring point （Huitengxile Grassland) during the re-greening, vigorous and withering periods was the highest, which was extremely significantly （P<0.01） higher than that in the other monitoring points; while G7 monitoring point （Urad Grassland within the boundaries of Baotou City） had the lowest STN at both vigorous and withering periods. The highest content of soil available phosphorus （SAP） was seen over the three observed periods in G6 monitoring point （artificial forage planting site）, which was significantly （P<0.05） or extremely significantly （P<0.01） higher compared with the other monitoring points. Over the three observed periods, the content of soil organic matter （SOM） in G4 monitoring point （Huitengxile Grassland） was the highest, which was extremely significantly （P<0.01） higher than that in the other monitoring points; while G7 monitoring point （Urad Grassland within the boundaries of Baotou City） had the lowest SOM. At the re-greening period, the contents of plant nitrogen, phosphorus and potassium in G6 monitoring point （artificial forage planting site） were the highest, which were extremely significantly （P<0.01） higher than those in the other monitoring points. At the vigorous period, the highest contents of plant nitrogen and potassium were observed in G8 monitoring point （Gegentala Grassland）, while the highest content of plant phosphorus was found in G6 monitoring point （artificial forage planting site）. At the withering period, G3 monitoring point （natural grassland within the boundaries of Ulanqab City） had the highest contents of plant nitrogen and phosphorus, while G4 monitoring point （Huitengxile Grassland） had the highest content of plant potassium. Over the three observed periods, the highest and the lowest contents of plant crude fiber were found in G5 monitoring point （Horqin Grassland） and in G4 monitoring point （Huitengxile Grassland）, respectively. For the score of soil nutrient status over the three observed periods, G4 monitoring point (Huitengxile Grassland) had higher rankings, while G7 monitoring point （Urad Grassland within the boundaries of Baotou City） showed the worst performance. As for the score of plant nutrient status, both G2 monitoring point （Urad Grassland within the boundaries of Bayannur City） and G6 monitoring point （artificial forage planting site） had the highest rankings at the re-greening period, followed by the vigorous period and the withering period; while all the other monitoring points exhibited the best performance in the vigorous period, followed by the re-greening period and the withering period. [Conclusion] There were obvious seasonal and regional variations in nutrient contents of the soil and vegetation in typical grasslands in Inner Mongolia. On the whole, the meadow grassland had higher comprehensive scores regarding soil nutrient contents during the re-greening, vigorous and withering periods, while the desert grassland had lower comprehensive scores across the three observed periods. Furthermore, the comprehensive scores of vegetation nutrient of different grassland types were generally higher at the vigorous period and lower at the withering period.

Salix psammophila is a shrub plant with functions of windbreak, sand fixation and soil conservation. In the development of unconventional feed resources in China, it is also a novel fodder resource with distinctive feeding value. It has high stress tolerance, large quantity, widespread distribution, low price, and rich nutrients. This paper reviews the ecological characteristics as well as ecological and economic value of Salix psammophila, and summarizes its feeding value and nutritional components. In addition, the feed treatment methods and processing technologies of shrub plants represented by Salix psammophila are generalized, the major challenges with feed utilization of shrub plants are examined, and effective approaches for their development and utilization are proposed, in hoping to provide references for the development and feed utilization of Salix psammophila and other shrub plants.

[Objective] The dietary nutrients apparent digestibility and daily gain of beef cattle at different growth stages were compared to provide references for ration formulation of beef cattle feeding. [Method] Two groups of Simmental crossbred cattle were randomly selected according to their age and weight. The light weight group comprised of ten 12- to 15-month-old cattle with weights of 250-300 kg. The heavy weight group comprised of ten 15- to 18-month-old cattle with weights of 350-500 kg. The diet was adjusted according to the weight change of beef cattle. The formal test period was divided into early and late test stages. Using ash insoluble in hydrochloric acid （AIA） as endogenous indicator, the apparent digestibility of dietary nutrients was determined by spot fecal collection method. [Result] The overall gain and average daily gain of the light weight group were significantly （P<0.05） different from those of the heavy weight group over the course of the experiment. In the early stage of the experiment, the apparent digestible amount of organic matter （OM）, crude protein （CP）, neutral detergent fiber （NDF）, acid detergent fiber （ADF）, starch, and energy in the diet of light weight group significantly （P<0.05） differed from that of heavy weight group. However there was no significant （P>0.05） difference in the apparent digestibility of OM, CP, NDF, ADF, starch, and energy between the two groups. [Conclusion] Under the conditions of the experimental diet composition, there was no significant difference in the apparent digestibility of dietary nutrients between the beef cattle at the two feeding stages, and the increasing digestible nutrient intake could increase the daily gain.

In order to support the control and elimination plan in areas where animal epidemic diseases are prevalent, and to conduct effective screening in areas where animal epidemic diseases are not prevalent, more accurate and sensitive diagnostic methods are expected be used. Digital PCR assay can be used in absolute quantification and detection of trace amounts of nucleic acids. Compared with the traditional detection methods, it does not rely on reference substances or standard products, shows higher tolerance to inhibitors, and has higher sensitivity and accuracy. As a novel tool for quantitative analysis of nucleic acid, digital PCR assay has recently been employed in the detection of animal epidemic diseases. This article summarizes and analyzes the principles, applications, existing problems, and developmental trends of digital PCR assay, in hoping to provide references for its further applications in detection of animal epidemic diseases.

The gut microbiota affects the growth and development and a number of related important economic traits in livestock and poultry. This paper reviews the research advances on the regulative roles of various feed additives in gut microbiota and growth traits in livestock and poultry. From the introduction of involved biological mechanism, the research progress of impacts of feed additives on gut microbiota and growth traits in livestock and poultry as well as effects of gut microbiota transplantation on host growth traits are enumerated. Furthermore, the practices of using feed additives to influence the gut microbiota and to improve the growth performance in livestock and poultry are summarized.

[Objective] To assess the effects of different levels of dried apple pomace （DAP） replacing part of the energy feed in concentrate supplements on in vitro rumen gas production, fermentation parameters, nutrients digestibility and growth performance of fattening Simmental cattle. [Method] Corns in concentrate supplements were partially replaced by DAP at proportions of 0, 4%, 8%, 12% and 16%, respectively. The rumen gas production of each group during 0 to 72 h of fermentation was monitored by using in vitro gas production method, and the fermentation parameters of the artificial rumen fluid were determined at the end of the in vitro gas production test. The nutrients digestibility of the artificial rumen fluid was measured at 48 h of in vitro fermentation. The weight gain indicators of the fattening cattle fed with diets in which corns were partially replaced by DAP at proportions of 4%, 8%, 12% and 16%, respectively, were assessed. [Result] The 4% DAP replacing group had significantly （P<0.05） higher total gas production in comparison to 8% and 16% DAP replacing groups. The gas production of each group was mainly observed in 4 to 24 h of fermentation and tended to be stable during 36 to 72 h of fermentation. After gas production, the pH value of the artificial rumen fluid of each group was in the normal range. The concentration of ammonia nitrogen （NH₃-N） of 8% DAP replacing group was significantly （P<0.05） higher than that of 12% and 16% DAP replacing groups. The concentrations of acetic acid, isobutyric acid, butyric acid, isovaleric acid, and valeric acid of 4% and 8% DAP replacing groups were significantly （P<0.05） higher than those of the remaining groups. The control group had significantly （P<0.05） higher digestibility of dry matter （DM）, crude protein （CP） and neutral detergent fiber （NDF） compared with the remaining groups, and 8% DAP replacing group had significantly （P<0.05） higher digestibility of acid detergent fiber （ADF） compared with the remaining groups. There were no significant （P>0.05） differences in total weight gain and daily weight gain during the test period among the fattening cattle in different groups. [Conclusion] Replacement of partial corns in concentrate supplements with 4% DAP increased the rumen gas production in in vitro fermentation of fattening Simmental cattle. 4% and 8% DAP replacements increased the concentrations of NH₃-N and volatile fatty acid （VFA） in rumen fluid, which was beneficial to rumen fermentation and diet digestion.

[Objective] According to the characteristics of vast activity area, insensitivity to the environment and delayed movement of free range cattle population, by referring the existing animal body size measurement technology, a non-contact body size measuring system on the basis of unmanned air vehicle （UAV） off-line 3D reconstruction method capable of collecting cattle point cloud data was develped to establish a wide coverage, precise, and high-efficient cattle body size measurement solution. [Method] Firstly, a quad-axis UAV was used to capture images, and some image processing techniques such as noise reduction with median filter and image three-channel histogram equalization were utilized to preprocess the image and to improve the reconstructed point cloud density and measurement accuracy. Secondly, the aerial triangulation measurement was conducted using the position and orientation system （POS） information from the image, and the 3D model was reconstructed after the initial coordinate data of point cloud was confirmed by adjustment computation. Finally, the point cloud of individual cattle was extracted by using random sample consensus （RANSAC） algorithm in point cloud library （PCL） and then interactive measurement was made. [Result] Images from 4 cattle herds and 1 individual cattle were collected, and available point cloud of body size data from a total of 21 cattle were reconstructed. In comparision to the convetional manual measurement method, the average relative errors in body height, body length and chest circumference measured by the developed UAV based system were 3.87%, 4.16% and 5.06%, respectively. [Conclusion] The UAV based system developed in this study can be used to measure body size of medium- and low-density free range cattle herds in Inner Mongolia, and the error is within the acceptable range.

Mycoplasma pneumonia caused by Mycoplasma ovipneumoniae （MO） is a devastating respiratory disease that puts the sheep industry at risk. MO infection is often insidious and persistent, resulting in reduced productive performance of diseased sheep and serious economic losses in sheep industry. By consulting the recent literature on molecular pathogenic mechanism of MO in China and abroad, we render a review from the following three aspects of adhesion of MO to respiratory epithelial cells, lower respiratory tract injuries caused by MO, and immune suppression induced by MO, in hoping to lay the groundwork for a more in-depth investigation on pathogenic mechanism of MO and for the development of innovative preventative and control strategies.

Under the background of rural revitalization strategy, the high-quality development of grassland animal husbandry in Inner Mongolia is one of the important parts in implementation of thriving businesses of rural revitalization strategy. Therefore, increasing the farmers′ income and pursuing the thriving businesses of rural revitalization strategy are of significance for the high-quality development of grassland animal husbandry in Inner Mongolia. Under the background of rural revitalization strategy, on the basis of elaborating the current situation of the development of animal husbandry in Inner Mongolia, and focusing on the outstanding problems in the high-quality development of grassland animal husbandry in Inner Mongolia, countermeasures and suggestions such as promoting resource conservation, improving the livestock products supply capacity, enhancing the international competitiveness of livestock products, strengthening the brand construction of green livestock products, and perfecting the financial support system are put forward, in hoping to provide references for promoting the high-quality development of grassland animal husbandry in Inner Mongolia.

[Objective] This study was conducted to explore the ovum pick-up and in vitro fertilization （OPU/IVF） technology in cattle, and to establish a high-efficient in vitro embryo production system for cattle. [Method] The fresh ovaries of healthy cattle collected from slaughterhouses were used as experimental materials to perform oocyte maturation as well as fertilization and embryo culture under in vitro conditions, with focus on the effect of leptin supplementation in culture medium on blastocyst rate. Healthy Holstein dairy cows （n=10） and Wagyu cattle（n=10） aged 13 to 15 months were selected as donors, and ovum pick-up as well as oocyte maturation and embryo production under in vitro conditions were carried out. For both breeds, the number of available oocytes and blastocysts was recorded, and the cleavage rates and blastocyst rates were calculated. After thawing of the prepared frozen embryos of the donors, Holstein dairy cows were used as recipients for embryo transfering. The pregnancy rates of the recipients receiving the in vitro produced embryos of the Healthy Holstein dairy cows and Wagyu cattle were measured on day 45 after embryo transfering. [Result] Addition of 30 U/mL leptin in the culture medium significantly （P<0.05） increased the blastocyst rate of the in vitro cultured cattle embryos of slaughterhouse origin. For the donors, 7.5 and 8.1 usable oocytes were averagely obtained per Holstein dairy cow and per Wagyu cattle, respectively. The cleavage rates of Holstein dairy cow and Wagyu cattle were 84.00% and 82.71%, respectively, and there was no significant （P>0.05） difference between them. Under the in vitro conditions, 4.3 and 3.7 available blastocysts were averagely obtained per Holstein dairy cow and per Wagyu cattle, respectively, and the blastocyst rate of Holstein dairy cow （57.33%） was significantly （P<0.05） higher than that of Wagyu cattle （45.68%）. The pregnancy rates of Holstein dairy cow embryo group and Wagyu cattle embryo group were 54.17% and 55.79%, respectively, and no significant （P>0.05） difference was observed. [Conclusion] The established OPU/IVF system effectively improves the utilization efficiency of high-quality female cattle, reduces its production costs, and provides references for the optimization of in vitro embryo production system for cattle.

Mycotoxins are secondary metabolites produced by fungi in grains and are often present in the contaminated livestock and poultry feed and feed raw materials. The mycotoxins commonly found in the feed samples include aflatoxin B₁（AFB₁）, ochratoxin A （OTA）, zearalenone （ZEA）, deoxynivalenol （DON）, and fumonisin （FUM）. Mycotoxins damage the immune system and reproductive function of livestock and poultry, and cause pathological alterations in the organs such as kidney, liver, and intestinal tract, affecting the health of livestock and poultry. This paper introduces the types and contamination situation of the commonly observed mycotoxins in livestock and poultry feed and feed raw materials, summarizes the research progress in the toxic effects of mycotoxins on livestock and poultry, and proposes corresponding prevention and control measures, in hoping to provide references for minimizing the harm caused by mycotoxin contamination in livestock and poultry production.

[Objective] To assess the effects of simulated drought stress with polyethylene glycol （PEG） on seed germination of Lespedeza davurica, Medicago ruthenica, and Coronilla varia. [Method] PEG solutions with concentrations of 0, 5%, 10%, 15%, 20% and 25% were used to simulate drought stress, and the seed germination experiments of the above three leguminous forage species were conducted. The germination percentage, germination index, mean germination time, and seedling vigor index of their seeds were analyzed, and their drought resistance were comprehensively evaluated to explore the germination properties under drought stress. [Result] The germination percentage, germination index and seedling vigor index of Lespedeza davurica and Medicago ruthenica seeds significantly （P<0.05） declined with the aggravation of drought stress, but their mean germination time significantly （P<0.05） increased. When PEG concentration reached 25%, the Lespedeza davurica seeds lost their vigor. The germination percentage, germination index and seedling vigor index of Coronilla varia seeds were significantly （P<0.05） higher than those of the control at 5%-10% of PEG concentrations, then dropped as the PEG concentrations increased. The comprehensive evaluation by membership function method demonstrated that the order of drought resistance of the three tested leguminous forage species at seed germination stage was Coronilla varia > Medicago ruthenica > Lespedeza davurica. [Conclusion] Simulated drought stress with PEG inhibits the germination of Lespedeza davurica and Medicago ruthenica seeds. PEG at low concentrations （≤10%） promote the germination of Coronilla varia seeds, however, higher concentrations （≥15%） have the reverse effect. Coronilla varia seeds have a stronger germination capacity in comparison with Medicago ruthenica and Lespedeza davurica seeds under drought stress.

[Objective] To study the effects of castration on lipid metabolism in male Chinese rural dogs. [Method] A total of twelve Chinese rural dogs of similar age and weight were divided into non-surgical group and castration group. The castration surgery was performed on the castration group dogs. The contents of triglyceride （TG）, total cholesterol （TC）, low density lipoprotein （LDL）, and high density lipoprotein （HDL） in serum were measured on the day before the surgery and the 14^th and 21^st days after the surgery. The effects of castration on lipid metabolism in male dogs were studied using the non-surgical group as control. [Result] Compare with the non-surgical group, the content of serum TG in the castration group increased significantly from day 14 to day 21 while the content of TC decreased when. The content of HDL on the 14^th and 21^st days was lower than the non-surgical group while LDL was higher and showed an upward trend overall. [Conclusion] The lipid metabolism of male Chinese rural dogs are affected by castration, resulting in the increase in triglyceride, the decrease in total cholesterol and high density lipoprotein, and the increase in low density lipoprotein.

[Objective] To better understand the characters and utilization status of natural grassland resources in Henan Province, and to provide a basis for better protection and rational utilization of local natural grassland in the future. [Method] According to the overall work plan for national grassland inventory formulated by the Ministry of Agriculture and Rural Affairs, field investigation of natural grassland resources in Henan Province was carried out from five aspects: grassland type, grassland area, vegetation productivity level, forage species, and utilization status. [Result] ①With a total area of 52.24×10⁴ hm², Henan Province has 4 categories and 30 types of natural grassland. 74.04% of the natural grassland is distributed in the mountainous and hilly areas of southern and western Henan Province. ②In natural grassland in Henan Province, there are around 1 400 forage plants, comprising 41 constructive species, 123 dominant species, and 357 main associated species. ③Natural grassland in Henan Province has an average grass layer height of 70.43 cm, an average coverage of 86.36%, and an average grass yield of 7.02×10³ kg/hm², with 94.40% of the natural grassland being underused or barely utilized. [Conclusion] Henan Province has abundant natural grassland resources, a diverse range of grassland varieties, high forage production and a lot of room for growth and application. Further development and utilization are necessary to boost the economic value of herbivorous animal husbandry.

[Objective] To analyze the cost-benefit of free-range beef cattle feeding and its influencing factors in China. [Method] Based on the associated statistical data of free-range beef cattle in Heilongjiang, Henan, Ningxia, Shaanxi and Xinjiang in the Compilation of National Agricultural Product Cost-benefit Data from the Year of 1999 to 2019, the cost and benefit as well as their structural changes in free-range beef cattle feeding were analyzed. Eviews 10.0 software was used to establish an analysis model. Seven indexes including calf cost, concentrate cost, green fodder and forage cost, death cost, medical and epidemic prevention cost, fuel and power cost, and labor cost were used as explanatory variables to analyze the effects of different production factors on the total production cost of free-range beef cattle feeding in the above five major production provinces and autonomous regions. [Result] From the year of 1998 to 2018, the total production cost of free-range beef cattle feeding in the five major production provinces and autonomous regions showed a slowly rising trend, the net profit also presented a fluctuating increasing trend, and the cost profit rate had been about 30% since the year of 2008. Among the direct costs of the material and service expense, the calf cost accounted for the highest proportion of the total production cost followed by feed cost. Except for fuel and power cost, the remaining direct costs exhibited an upward trend. The indirect costs displayed a trend of decreasing first and increasing then. Since the year of 2009, the labor price in working day and labor hiring price had increased simultaneously, and the proportion of labor cost in the total production cost had been increasing. Among the factors of production, calf cost, concentrated cost and labor cost were the dominant ones that affected the total production cost of free-range beef cattle feeding, and were positively correlated with the total production cost. [Conclusion] From the perspective of the cost-benefit of free-range beef cattle feeding in the five major production provinces and autonomous regions, the production cost was constantly increasing, and the benefit was good. It was recommended to expand the feeding scale appropriately so as to control the marginal cost.

Amoxicillin （AMO） is one of the semi-synthetic β-lactamic antibiotics. It is widely used in veterinary clinic due to its strong acid resistance, good bactericidal effect, broad antibacterial spectrum, high water solubility, and various dosage forms. This paper reviews the physical and chemical properties, antibacterial mechanism, safety, and applicability in treatment of animal infectious diseases of AMO, in hoping to offer references for its scientific and rational use in veterinary clinic.

[Objective] To establish a method for preparing turbid microbial suspension agent and to evaluate its stability. [Method] Microbial water suspension system was prepared with xanthan gum and sodium carboxymethyl cellulose as stabilizers and microbial feed additive powder agent as suspension components. The stability of the prepared suspension agent was evaluated using indexes including stability coefficient, viscosity, storage stability, cold storage stability, and total number of viable bacteria. [Result] With the increase of stabilizer proportion, the stability coefficient of suspension agent increased gradually. When 0.20% stabilizer was added, the stability coefficient of the system rose to 91.38% which was significantly （P<0.01） higher than the control. The viscosity of the suspension system elevated with the increase of stabilizer addition amount and the decrease of storage temperature. When the stabilizer addition ratio was 0.20%, the system had no stratification and reached a stable state. After 24 hours of cold storage at 4 ℃, the number of viable bacteria in the suspension agent with 0.10% stabilizer declined. With 0.10%-0.25% stabilizer addition, the number of viable bacteria was significantly （P<0.05） lower than the control, but remained above 10⁹ CFU/mL. [Conclusion] There is no stratification in the prepared turbid microbial suspension agent for feed use when the addition amount of stabilizer is 0.20%. The number of viable bacteria in the prepared suspension agent remains above 10⁹ CFU/mL after 24 hours of cold or room temperature storage, ensuring the effective amount of viable bacteria in the microbial agent for feed use.

Music is a form of artistic expression created by humans using sound. A large number of studies have shown that part of music has a certain positive impact on humans and animals. This article reviews the effects of music on animal behavior, neuroendocrine function, immunity function and productive performance, as well as the potential regulatory mechanism of music on animals, in hoping to provide a theoretical basis for further applying music as a technical way to regulate the welfare and physiological activities of animals.

The food safety supervision model developed by the European Union （EU） serves as a benchmark for the entire world, and the direction of food safety risk research conducted by the EU also serves as a wind vane for the sector. This study examined and interpreted the establishment and structure of the EU food safety supervision organization′s framework, the allocation of each organization′s powers and duties, the makeup of the regulations and standards system, and the detailed supervision activity implementation specification documents. In parallel, the enlightenment of the EU food safety supervision system on Chinese food safety supervision was proposed, in hoping to serve as a guide for clarifying the implementation mechanism of the EU food safety supervision, improving the efficiency of trade activities of Chinese food export enterprises, and enhancing the function of Chinese food safety supervision.

[Objective] The aim of the present study was to analyze the research trend and hotspot of heavy metal passivation during organic waste composting process. [Method] The literature published from 2000 to 2022 and indexed by the Web of Science （WoS） core collection database on heavy metal passivation during organic waste composting process were used as the data source. CiteSpace 6.2.R6 and VOSviewer 1.6.18 bibliometric visualization software were employed to assess the number of publications and the corresponding countries （regions）, authors, institutions and keywords, and to clarify the research trend and hotspot in this research field. [Result] From 2000 to 2022, a total of 1 266 papers on heavy metal passivation during organic waste composting process were published, with an overall upward trend in annual publication volume. From 2020 to 2022, 345 papers were published, accounting for 27.25% of the total number of publications. Chinese scholars led the research field in terms of publication volume by countries （regions）, with 301 papers published, accounting for 23.78% of the total number of publications. From the perspective of publication volume and collaborative relationships among the authors, KALAMDHAD Ajay S and ZHANG Zengqiang had the highest number of publications, and both published 23 papers, accounting for 1.82% of the total number of publications. The highest number of collaborative authors were observed between the teams of ZHANG Jiachao and ZENG Guanming, indicating an intimate collaborative relationship. From the perspective of institutional publication volume and collaborative relationships, the Spanish National Research Council ranked the first with 96 papers published, accounting for 7.58% of the total number of publications. The Spanish National Research Council and the Chinese Academy of Sciences were the most active institutions in this research field and had the closest collaboration with the other institutions. The top 6 keywords with high occurrence frequency were heavy metals, sewage sludge, municipal solid waste, organic matter, soil and compost, with occurrence frequencies of 724, 441, 210, 187, 158 and 158, respectively. Among the top 10 keywords with high occurrence frequency, sewage sludge, bioavailability, growth, heavy metals, municipal solid waste and soil had intermediary centrality greater than 0.1, and their intermediary centralities were 0.78, 0.52, 0.42, 0.30, 0.25 and 0.18, respectively. A total of 10 categories of keywords were clustered in this research field, including sewage sludge, organic amendments, organic fraction of municipal solid waste, greenhouse gas, C/N ratio, heavy metals, organic waste, and so on. The keyword zinc had the highest burst strength at 16.57 and received attention from 2004 to 2015. Biochar, food waste, microbial community, transformation and organic amendments were the dominant burst keywords from 2017 to 2022. [Conclusion] This study clarified the research trend and hotspot of heavy metal passivation during organic waste composting process. The impacts of different organic wastes on heavy metal passivation, the form transformation and stability of heavy metals in organic waste composting, and the enrichment and transfer of heavy metals in composting products may be the focus of the future research.

[Objective] To see how varied precipitation gradients and stocking rates affect ecosystem carbon exchange. [Method] In the Stipa breviflora desert steppe in Siziwang Banner, Ulanqab City, Inner Mongolia, the experiment incorporated a simulated precipitation test （50% precipitation reduction, natural precipitation, 50% precipitation increase and 100% precipitation increase） to the platform of varied stocking rates （CK, low stocking rate, moderate stocking rate, and high stocking rate). During the plant growing season in the year of 2017, the Li-6400 portable photosynthetic instrument and closed box method were used to measure the responses of net ecosystem carbon exchange （NEE）, ecosystem respiration （ER）, and gross ecosystem productivity （GEP） to different precipitation gradients and stocking rates. [Result] ① Precipitation alone had significant （P<0.001) effect on NEE, ER and GEP. ②ER in the high stocking rate treatment group was significantly （P<0.05） lower than that in CK. ③Interaction of precipitation and stocking rate had a statistically significant （P<0.05） influence on GEP only. Under the same stocking rate, NEE, ER, and GEP increased with precipitation increase. With the same precipitation rate, ER and GEP in CK were significantly （P<0.05) higher than those in the high stocking rate treatment group. Under the low stocking rate, the absolute value of slope in the established linear regression model among ER, GEP and Vwc was the highest. [Conclusion] NEE, ER, and GEP all increased significantly as soil water content increased. ER decreased significantly as stocking rate increased. The interaction between precipitation and stocking rate only had a significant impact on GEP. Although increased water facilitated ecosystem carbon exchange, under moderate and high stocking rates, the desert steppe ecosystem carbon exchange had reduced sensitivity to the change of soil water content.

[Objective] To analyze the state of grassland ecological protection research in China and investigate the most recent developments in order to provide suggestions and references for future study. [Method] Using the China National Knowledge Infrastructure （CNKI） database as the data retrieval source, CiteSpace software was employed to quantify the annual publication volume, author, organization, and keyword of 315 valid sample documents from the year of 1992 to 2021. [Result] Since the year of 2007, the number of annual publications in the field of grassland ecological protection in China has steadily increased, peaking in the year of 2009. Following then, the quantity of relevant documents reduced, but remained quite high. NING You-liang and HE You-jun are high-yield authors in the sector.The network of team cooperation has taken shape. LIU Tian-ming's team cooperates closely with other teams. There had been lots of cooperation among institutions, but only limited to certain regions and disciplines, deep cooperative relationships has not formed. At present, the research hotspots in the field of grassland ecological protection in China are primarily focused on grassland ecological protection subsidy and reward policy, grassland animal husbandry, grassland sustainable development and so on. [Conclusion] In China, grassland ecological protection research has yielded a wealth of information. Future study should focus more on grassland ecological restoration and management, as well as grassland ecological protection subsidy and reward policy.

In recent years, researchers have discovered that animals contain a type of non-self-derived miRNA, which were always ingested by food and have regulatory functions in animals. These findings may provide some theoretical foundations for extracting specific compounds from plants as additives or investigating the mechanisms underlying the therapeutic role of Chinese herbal medicine. They also broaden the research scope of exogenous animal and plant miRNA. From the aspects of formation process, structural characteristics, stability post cross-kingdom, tissue-specific expression, target gene binding mode, biological function, and cross-kingdom regulation, this paper systematically illustrated the mechanisms underlying the cross-kingdom gene regulation of animal and plant miRNA, reviewed corresponding research progress, and forecasted future research directions and applications of animal and plant miRNA, in hoping to serve as a guide for the development and utilization of miRNA in disease treatment and nutritional supplementation.

[Objective] This study aimed to analyze the current situation and benefits of cashmere goat industry in Ordos City, Inner Mongolia, and to provide references for accelerating the high-quality development of animal husbandry in this area. [Method] Taking Otog Banner, the main cashmere producing area of Ordos City, as the research object, and the relevant data of 100 herdsmen engaging in cashmere goat farming were obtained through household survey from the year of 2020 to 2022. The management structure and the cashmere goat farming structure of the local herdsmen were analyzed. Furthermore, the DEA analysis model was constructed to calculate the comprehensive efficiency, pure technical efficiency, scale efficiency and scale returns of the herdsmen with less than 500 cashmere goats （small scale）, 500-699 cashmere goats （small and medium-sized scale）, 700-899 cashmere goats （medium scale）, 900-1 099 cashmere goats （medium and large-sized scale）, and above 1 100 cashmere goats （large scale）, respectively. [Result] The number of cashmere goats in this area showed an upward trend. Although the number of the other livestocks increased, it was far less than that of cashmere goats. The reproduction rate of reproductive female goats maintained a higher level, and the rate of twin goat kids was greatly increased. The combination of cashmere and meat production was the main mode of cashmere goat farming. The low age cashmere goats were used to produce fine cashmere, and the high age cashmere goats were mainly used to produce meat. The comprehensive efficiency of cashmere goat farming in Ordos City was at a low level, and the comprehensive utilization of infrastructure was insufficient. Under the current technology and management level, small scale herdsmen were more efficient in using the input resources, and their benefits were increased more significantly through improving the technology and management level. The average value of scale efficiency of large scale herdsmen was greater than that of pure technical efficiency, while the average value of scale efficiency of the other scale gradients was less than that of pure technical efficiency. Small scale herdsmen were more likely to improve the farming benefits by increasing input, while large scale herdsmen could obtain the optimal production benefits without the necessity for a further increase in factor input. [Conclusion] The cashmere goat industry in Ordos City has good development foundation, huge development potential and continuously improved production benefits, which exerts a great promotive role in increasing the income of local herdsmen. Households of different farming scales need to realize resource sharing by integrating resources, and to improve resource utilization by developing standardized farming. These measures can improve the cashmere goat farming benefits to a certain extent.

Probiotics are living microbial feed supplement that not only improve production performance, boost immunity, maintain gastrointestinal flora balance, clean the gastrointestinal environment, but also play an important role in preventing and treating diarrhea and regulating host immune function in animals. Probiotics can be utilized as replacement for antibiotics because of their high-level safety, no residue and no drug resistance. In equine animals, probiotics have been frequently employed and show promising outcomes. This paper provided a summary for the action mechanism of probiotics and related active substances, as well as the current issues and application prospects of equine probiotics, in hoping to serve as a guide for the development and application of equine probiotics.

[Objective] The aims of the present study were to isolate and identify the Staphylococcus aureus （S. aureus） strain from fecal samples of lambs with diarrhoea, and to characterize the antimicrobial resistance and pathogenicity of the isolate. [Method] Four anal swab samples of diarrheic lambs were collected from a sheep farm in Emin County, Tacheng Prefecture, Xinjiang Uygur Autonomous Region, and S. aureus strain was selectively isolated with mannitol salt agar （MSA）. The isolate was identified by morphological observation and 16S rDNA sequence analysis. The in vitro susceptibility of the isolate to 11 antimicrobial agents belonging to 9 categories was analyzed by paper diffusion method. The presence of virulence genes of the isolate was detected by PCR assay. A model of abdominal infection in Kunming mice was established to evaluate the pathogenicity of the isolate. [Result] One suspected S. aureus strain was isolated from the four fecal samples of diarrheic lambs. It formed glossy, moderately raised, golden or lemon coloured colonies on MSA. Gram staining and morphological observation revealed that the isolate was Gram-positive and arranged in the form of grape bunches. The 16S rDNA sequence of the isolate was 100% similar to that of a S. aureus isolate of porcineluny origin from Changsha City, Hunan Province, China. Morphological observation and 16S rDNA sequence analysis confirmed that the isolate was S. aureus. The isolate was resistant to penicillin, clindamycin, cefotiamine, rifampicin and erythromycin, and was sensitive to gentamicin, azithromycin, chloramphenicol, norfloxacin, cefoxitin and cotrimoxazole. Out of the 20 virulence genes belonging to 8 classes tested, the presence of sea, seg, sei, eta, clfA and clfB genes was observed. The LD₅₀ of the isolate for Kunming mice was 2.24×10⁸ CFU/mL, with observable pathological changes in the organs of the dead mice. [Conclusion] One S. aureus strain was isolated and identified from the fecal samples of diarrheic lambs in a sheep farm in Emin County, which exhibited a multi-drug resistant phenotype, harbored multiple virulence genes and had certain pathogenicity. The results of this study provide references for the rational use of medication for the diseases caused by S. aureus infection in sheep in this region.

[Objective] The aim of the present study was to explore the responses of antioxidant capacity of different parts of alfalfa to the exogenous selenium priming duration, and to provide references for the production of selenium-rich alfalfa grass products by seed priming technology. [Method] Alfalfa seeds were subjected to priming treatment with 0.5 mmol/L sodium selenite solution for 0, 3, 6, 9, and 12 h, respectively. The activities of superoxide dismutase （SOD）, catalase （CAT）, ascorbate peroxidase （APX） and glutathione reductase （GR） as well as the content of malondialdehyde （MDA） in the whole plant, cotyledon, and radicle of the alfalfa seedlings treated for different priming durations were determined and statistically compared. [Result] With the prolongation of selenium priming duration, the activities of SOD, CAT, APX, and GR of the whole plant, cotyledon, and radicle of the alfalfa seedlings all increased, whereas their content of MDA increased first and then decreased. For the whole plant, cotyledon, and radicle, significantly （P<0.05） lower and significantly （P<0.05） higher activities of both SOD and CAT were observed at 0 h and 12 h priming compared with the other priming durations, respectively. The APX activity of cotyledon was significantly （P<0.05） reduced at both 0 h and 3 h priming, and was significantly （P<0.05） elevated at 12 h priming. The significantly （P<0.05） lowest and the significantly （P<0.05） highest APX activity of both radicle and whole plant were observed at 0 h and 12 h priming, respectively. The whole plant, cotyledon, and radicle had the significantly （P<0.05） lowest GR activity at 0 h priming. Their GR activity all reached to the peak at 12 h priming, with a statistically significant （P<0.05） difference observed in the whole plant. The lowest MDA content of cotyledon was observed at 12 h priming, which exhibited statistically significant （P<0.05） differences compared with that at 0 h and 3 h priming. The MDA content of the whole plant peaked at 3 h priming, declined at 6 h priming, and decreased to the lowest level at 12 h priming, showing statistically significant （P<0.05） differences compared with that at 0 h, 3 h, and 6 h priming. The MDA content of the radicle peaked at 3 h priming, declined at 6 h priming, and decreased to the lowest level at 12 h priming, showing statistically significant （P<0.05） differences compared with the other priming durations. Under the same priming duration, the activities of SOD, CAT, APX, GR and the content of MDA in the radicle were all significantly （P<0.05） higher than those in the cotyledon and whole plant, with radicle being the highest followed by the whole plant and cotyledon. [Conclusion] The effects of selenium priming on the antioxidant capacity depended on the parts of the alfalfa seedlings and priming duration. The antioxidant enzyme activities of the whole plant, cotyledon and radicle of the alfalfa seedlings increased with the prolongation of selenium priming duration, while the change trend of MDA content was the opposite. Selenium priming had limited affects on the cotyledon and had great affects on the radicle. For the alfalfa seedlings, selenium priming concentration at 0.5 mmol/L (sodium selenite solution) and priming for 12 h were the optimal conditions.

[Objective] The present study aimed to assess the anesthetic effect of xylazine hydrochloride in rabbits. [Method] Twelve New Zealand rabbits were assigned into the following four groups at random with 3 rabbits in each group: an ear intravenous injection （IV） with fixation group, a buttocks intramuscular injection （IM） with fixation group, an ear IV without fixation group, and a buttocks IM without fixation group. The rabbits in different groups were given xylazine hydrochloride at a dosage of 3 mg/（kg·BW） by corresponding administration approaches. After administration, the rabbits in the fixation groups were in supine position with head and limbs fixed, and those in the non-fixation groups were in natural prone position. Thirty min post the first administration, the rabbits were given xylazine hydrochloride again at a dosage of 2 mg/（kg·BW） by the same approach as the first administration. Basic vital signs and anesthetic reaction indexes of the rabbits were monitored 10 min prior to administration as well as 5, 30 and 60 min post the second administration. [Result] The respiratory and pulse frequencies of the four groups after administration of xylazine hydrochloride decreased significantly or extremely significantly （P<0.05 or P<0.01） compared with those before administration. At 60 min after administration, the pulse frequency of IM fixation group was the lowest, which was significantly （P<0.05） lower than that of IV non-fixation group. The rectal temperature of the four groups at 30 min after administration was significantly （P<0.05） lower than that before administration. Except for the IV non-fixation group, the rectal temperature of each group at 60 min after administration was extremely significantly （P<0.01） lower than that before administration. At 60 min after administration, the rectal temperature of IM fixation group was the lowest, which was extremely significantly （P<0.01） lower than that of IV non-fixation group. In IM fixation group, no righting reflex, eyelash reflex and pain reflex were observed at different time points after administration. In IV non-fixation group, the righting reflex, eyelash reflex and pain reflex were observed in all 3 rabbits at 60 min after administration.The anesthetic period of IM fixation group was the longest, which was significantly （P<0.05）longer than that of IV fixation group and was extremely significantly （P<0.01） longer than that of IV non-fixation group and IM non-fixation group. [Conclusion] Xylazine hydrochloride should be administered by the route of IM in anesthesia of rabbits. A first administration at the dosage of 3 mg/（kg·BW） is recommended, and a subsequent administration at the dosage of 2 mg/（kg·BW） should be given 30 min later. The rabbits should be fixed immediately after administration.

African swine fever （ASF） is an acute and hemorrhagic infectious disease caused by the African swine fever virus （ASFV） in farmed pigs and wild boars. Pigs infected with a highly virulent ASFV strain have a near 100% mortality rate, resulting in massive economic losses for the pig industry. ASFV spreads quickly and effectively in pigs and persists in the environment, posing challenges for prevention and control of ASF. The development of ASF vaccine has been a priority for researchers. There hasn′t been a successful vaccine on the market yet. In order to give a reference for successful research and development of ASF vaccine, this paper reviewed the current research status of ASF inactivated vaccine, live attenuated vaccine, subunit vaccine, DNA vaccine, and live viral vector vaccine.

[Objective] To assess the effects of dietary supplementation of active dry yeast （ADY） on feed digestibility and daily gain of fattening Simmental cattle. [Method] A total of 30 Simmental cattle were randomly split into three groups. Group A was the control, groups B and C were the experimental groups. Group A was fed with the basal diet, and groups B and C were fed with the basal diets supplemented with NO.1 ADY （10 g/d） and NO.2 ADY （10 g/d） twice daily, respectively. The pre-feeding phase was 5 days followed by 28 days formal trial period. Fecal separation sieve was used to assess the feed digestibility of the experimental fattening cattle, and the daily gain was monitored. [Result] On day 21 of the experiment, the proportion of up-level fecal sieve residue in group C was significantly （P<0.05） lower than that in group A. On the 28^th day of the experiment, group C had lower proportion of middle-level fecal sieve residue than groups A and B, and was significantly （P<0.05） lower than that on the 7^th, 14^th, and 21^st days of the experiment. The proportion of lower-level fecal sieve residue in group C was the highest on the 28^th day of the experiment, and was significantly （P<0.05） higher than that on the 7^th and 14^th days of the experiment. The average daily gain of the two experimental groups was higher than that of the control group. The average daily gain of group C was significantly （P<0.05） higher than that of group A and group B. [Conclusion] Dietary supplementation of NO.1 and NO.2 ADY increased the daily gain of fattening Simmental cattle and enhanced the feed digestibility to a certain degree. NO.2 ADY exhibited a better effect.

Bone is the basic framework of the body structure. The dynamic homeostasis between bone formation and bone resorption determines the bone health. Calcium and phosphorus are important mineral elements involved in animal bone growth and development, and their absorption and regulation by the body directly affect the bone metabolism. Changes in serum calcium and phosphorus levels alter the body′s secretion of relevant regulatory hormones that affect bone development. Therefore, calcium and phosphorus metabolism is closely related to bone health. Based on the researches on calcium and phosphorus metabolism as well as bone metabolism abroad and in China, this paper reviews the absorption and metabolism of calcium and phosphorus, their contents and proportions, and the regulatory mechanism of calcium and phosphorus metabolism related adjusting hormones on bone development, in hoping to provide references for further studies on the regulation of calcium and phosphorus metabolism and bone in animals.

[Objective] This study aimed to characterize the changes in whole transcriptome expression profile of breast muscles during the growth process in Xichuan black-bone chicken before and after hatching. [Method] Breast muscle samples were collected from the Xichuan black-bone chicken embryos incubated for 14 d （marked as X-14 d） and the chicks freshly hatched for 1 d （marked as X-1 d）, respectively. Eukaryotic whole transcriptome sequencing analysis were performed around coding RNA （messenger RNA, mRNA） and non-coding RNA （lncRNA, circRNA and miRNA）. [Result] During the growth process of breast muscles in Xichuan black-bone chicken, the transcriptome levels of a large number of genes had significant changes. Compared with the chicken embryos incubated for 14 d, the chicks freshly hatched for 1 d （X-14 d vs X-1 d） had a total of 3 858 differentially expressed mRNA, including 1 054 upregulated genes and 2 804 downregulated genes. There were 371 differentially expressed lncRNA, including 222 upregulated genes and 149 downregulated genes; there were 316 differentially expressed circRNA, including 148 upregulated genes and 168 downregulated genes; there were 377 differentially expressed miRNA, including 159 upregulated genes and 218 downregulated genes. GO enrichment analysis showed that differentially expressed mRNA was involved in multiple biological processes, such as biological process regulation, stimulus response, localization, positive/negative regulation of biological processes, growth processes, immune system processes, etc. The KEGG pathway enrichment analysis of differentially expressed mRNA demonstrated that multiple signaling pathways were enriched, including adhesion junction, actin cytoskeleton regulation, amino acid biosynthesis, oxidative phosphorylation, carbon metabolism, citric acid cycle （TCA cycle）, tight junction, gap junction, metabolic pathway, focal adhesion, glycolysis/gluconeogenesis, pyruvic acid metabolism, melanogenesis, Notch signaling pathway, etc. The significantly differentially expressed genes were mainly related to multiple biological traits of Xichuan black-bone chickens such as growth trait, meat quality trait, lipid trait, melanogenesis trait, and immune system. [Conclusion] As important components of the transcriptome, mRNA, lncRNA, circRNA, and miRNA played crucial roles in the growth and development of Xichuan black-bone chicken. Our results provided references for analyzing the genetic regulation mechanism in the growth and development process of breast muscles in Xichuan black-bone chicken.

Application of plant extracts in prevention and treatment of dairy cow mastitis conforms to the national requirement and industry trend of reducing and limiting use of antibiotics. This paper summarizes the commonly used extraction methods for plant active ingredients, introduces the underlying mechanism of bacterial mastitis, and reviews the antibacterial, anti-inflammatory and immunomodulatory mechanisms of plant active ingredients, in hoping to provide new insights into the selection of drugs for treatment of dairy cow mastitis in veterinary clinic.

With the large-scale and intensive development of animal husbandry, livestock and poultry breeding has become one of the main sources of agricultural non-point source pollution in China. The resource utilization of livestock and poultry manures is not only critical for ensuring the healthy and sustainable development of animal husbandry, but it is also a vital step toward achieving the long-term goal to construct ecological civilization and build a community with a shared future for mankind from the perspective of sustainable development. The ability to achieve coordination and unity in livestock and poultry pollution management and economic development is made possible by the agricultural production mode of planting-breeding combination. Through analyzing the origins of greenhouse gases in production, processing and consumption of animal husbandry, this paper summarizes the general solutions of source reduction, process control, and end treatment of livestock and poultry breeding, in hoping to provide references for farm households, animal breeding enterprises, and local governments with similar characteristics, to improve the resource utilization efficiency of livestock and poultry manures, and to promote carbon neutrality in animal husbandry.

Astragalus membranaceus contains a variety of bioactive substances including polysaccharides, saponins and flavonoids, and has the activities of enhancing immunity, anti-oxidation, anti-bacteria, anti-virus, anti-tumor, anti-aging, regulating blood pressure and preventing diabetes. The application of Astragalus membranaceus helps to boost the body′s immune system and anti-oxidation system of livestock and poultry, and improve the growth performance and product quality. The biological activities of Astragalus membranaceus and its application in livestock and poultry production were reviewed, in hoping to provide references for the research, development and application of Astragalus membranaceus products for animal use.

[Objective] To conduct an empirical research on the development of forage industry in China using alfalfa as an example from the perspective of food security, and to provide references for resolving the contradiction between people and animals for grain, achieving the balance between supply and demand of feed grain, and guaranteeing grain security. [Method] The gray correlation method was used to empirically analyze the influencing factors of feed grain growth. The influencing factors of feed grain period-by-period growth were used as the subsequence, and the feed grain period-by-period growth was used as the parent sequence to establish an analytical model. According to the ranking of correlation degree, the major factors influencing feed grain growth were determined. [Result]The correlation degree of the period-by-period growth of total output value in animal husbandry, the period-by-period growth of main livestock products, the period-by-period growth of perennial forage planting area and the period-by-period growth of annual forage planting area with the period-by-period growth of feed grain were 0.949, 0.893, 0.858, 0.831, and 0.551, respectively. This indicated that there were strong correlation between the growth of feed grain and the total output value in animal husbandry, the main livestock products and the perennial forage planting area. Furthermore, the growth of animal husbandry and feed grain were closely related, and the development of perennial forage industry could alleviate the rising demand for feed grain in China. [Conclusion] The results obtained in this study may provide empirical support and reference for the development alfalfa forage industry and the formulation of related policies in China.

[Objective] The aims of this study were to prepare the polyclonal antibody against capsid （CA） protein of a maedi-visna virus （MVV） strain isolated from naturally infected sheep and to assess its specificity. [Method] A set of specific primers was designed according to the CA gene sequence of MVV Inner Mongolia strain, and the CA gene was subsequently amplified by PCR assay for constructing a recombinant plasmid. The MVV CA recombinant protein was prokaryotically expressed and purified. The rabbit-derived polyclonal antibody against MVV CA recombinant protein was prepared, and its titer and specificity were determined and identified by using indirect ELISA assay as well as Western blot and immunohistochemical analyses. [Result] The prokaryotic expression system of MVV CA recombinant protein was successfully constructed, and the target protein was about 27 kDa after purification. The titer of the prepared polyclonal antibody was determined as 1∶8 192 by indirect ELISA assay. Western blot analysis showed that there was a specific band with a size of 25 kDa in lung tissues of sheep infected with MVV. Immunohistochemical analysis demonstrated that there were obvious brownish yellow positive signals in cytoplasm of macrophages in lung tissues of sheep infected with MVV. [Conclusion] Polyclonal antibody prepared with soluble recombinant MVV CA protein had good specificity, which might serve as a candidate antibody in MVV serological diagnosis technology.

Subacute ruminal acidosis （SARA） is a nutritional metabolic disease with a high frequency in dairy farming. With the development of intensive dairy farming in China, feeding a large amount of high-energy grain feed to improve the production performance of dairy cows is prone to develop SARA, which lowers the ruminal fluid pH value, alters the ruminal bacterial flora, impairs the ruminal epithelial mucosa, and eventually affects the ruminal metabolic function. This paper analyzed the predisposing factors of SARA including various physiological stages, feed intake behaviors and individual differences of dairy cows, discussed the affects of SARA on the changes of ruminal bacterial flora, gene expression of ruminal epithelial cells and ruminal barrier function of dairy cows, in hoping to provide references for elucidating the mechanisms of ruminal function damage caused by SARA and reducing the risk of SARA in dairy cows.

[Objective] This study aimed to analyze the structure and function of African swine fever virus （ASFV） pI215L protein. [Method] A total of 29 pI215L gene sequences of different ASFV strains were downloaded from the African Swine Fever Virus Database （ASFVdb）. Bioinformatics tools were used to analyze the homology and genetic evolution of pI215L gene of different ASFV strains, and to predict the physicochemical properties, secondary structure, linear epitope, and three-dimensional spatial location of pI215L protein. [Result] The pI215L gene sequences had high homology among different ASFV strains. The pI215L protein was unstable and hydrophilic. Its secondary structure mainly contained four forms, including α-helix, extend strand, β-turn, and random coil, and had a domain of E2 Ubiqutin-conjugating enzyme. A total of 16 peptide fragments were potential linear epitopes. SWISS-MODEL was used to complete homology modeling of the tertiary structure of pI215L protein, and its homology with 6NYO.1 （ubiquitin-conjugating enzyme E2 R2 and ubiquitin） in the PDB database was 46.06%. The PyMOL software was used to predict the conformational epitopes of pI215L protein to accurately locate the distribution of the predicted three-dimensional spatial position of the epitopes in the model. [Conclusion] Our results provided references for unravelling the structure and function of pI215L protein, as well as developing vaccines and drugs for prevention and control of ASFV.

Pepper, serving as both condiment and vegetable, plays an important role in human daily diet and health. In addition, pepper and its extracts can boost livestock and poultry productivity by enhancing disease resistance, improving feed conversion ratio, and alleviating heat stress. This paper introduced three application modes of pepper （pepper powder, capsaicin, capsicum oleoresin） as feed additives, as well as its application and action mechanisms in poultry, pigs, ruminants, rabbits, rats and aquatic animals, in hoping to provide a fresh perspective on the use of pepper and its extracts in animal production.

Gut flora is a complex ecosystem composed of microorganisms, which can convert the nutrients that enter the intestine into substances required for the healthy growth and development of body. Gut flora plays a key role in maintaining the normal substance digestion, nutrient absorption, energy conversion and metabolic process of the animals. Numerous studies have been conducted recently on the influence and mechanism of gut flora on animal bone growth. The impact and mechanism of gut flora on bone metabolism were reviewed from the perspectives of its role in nutrient absorption, immune and endocrine functions of animals, and the effects of its metabolites, in hoping to serve as a guide for the prevention and treatment of animal bone diseases.

Denmark is a major producer of livestock products in the European Union（EU）. As a major supplier of dairy and meat to European countries, exports account for two-thirds of the country’s agricultural and animal husbandry products. The number of dairy farms in Denmark has been declining in recent years, but the breeding scale has been gradually increased. With the use of new technologies, unit yield of dairy cows has been consistently improving, so as the yield of fresh milk has been steadily increasing as well. There are 24 dairy processing firms currently, comprising cooperatives and commercial enterprises, after the concentration and integration of the dairy processing industry. Danish dairy processing enterprises established a reasonable milk price setting mechanism and provided efficient third-party services for pastures to ensure the healthy development of the industrial chain. Danish and European consumers have good dairy consumption habits, however liquid milk consumption has reached saturation, whereas cheese consumption is continuously increasing. Denmark has long been a net exporter of dairy products, with other EU nations and Asian nations being its primary dairy market. Over the years, China and Denmark have developed a strong dairy cooperation relationship. In the future, the two countries will further strengthen and broaden dairy cooperation, promote the construction of the whole industrial chain of China’s dairy industry, and accelerate the sustainable development of the dairy industry of the two countries.

Improved livestock and poultry breeds are critical to the development of animal husbandry industry. They are not only the foundation for development of regional animal husbandry industry, but also the focus of competition in science and technology of animal husbandry industry among various countries. Modern breeding technology of improved livestock and poultry breeds is composed of a series of technologies. Its employment in animal husbandry production aids in increasing the application efficiency of high-quality livestock and poultry for breeding use, speeding up the process of regional livestock and poultry breeding improvement, and improving livestock and poultry production performance. This paper introduced the application status of the main breeding technology of improved livestock and poultry breeds in China, analyzed the impacts of modern breeding technology of improved livestock and poultry breeds on feed and forage conversion efficiency as well as on selection efficiency of improved livestock and poultry breeds. In addition, this paper discussed the relationship between modern breeding technology of improved livestock and poultry breeds and input and output of livestock and poultry farm from economic perspective, in hoping to provide references for the construction of a modern breeding system for improved livestock and poultry breeds in China.

[Objective] The P113 genes of Mycoplasma ovipneumoniae isolates from Inner Mongolia were cloned, and the P113 protein sequences of various isolates were bioinformatically compared and analyzed, so as to provide references for clarifying the biological function of Mycoplasma ovipneumoniae P113 protein. [Method] A set of specific primers were designed to amplify the P113 gene fragments of 9 isolates of Mycoplasma ovipneumoniae from Inner Mongolia. The obtained P113 gene fragments of various isolates were sequenced. The DNA sequences were then translated into amino acid sequences, and the differences in amino acid sequences among various isolates were bioinformatically compared. [Result] The PCR amplified products of P113 gene of various isolates varied in size. According to amino acid sequence analysis, the lengths of C-terminal repetitive elements were variable. KKAEGA (S) QNQG was the dominantly observed repetitive element. The number of repetitive elements of the isolates varied. The most repetitive elements were found in the NM01-MO isolate and CK-MO isolate, both of which were 16. The least repetitive elements were found in the LK-MO isolate, which were 3. Most isolates had large differences in the number of repetitive elements. [Conclusion] The number of C-terminal repetitive elements in the amino acid sequence of P113 protein of Mycoplasma ovipneumoniae isolates from Inner Mongolia was variable. These repetitive elements had an impact on P113 protein structure, which could then have an impact on its biological activity.

[Objective] To determine the causes of morbidity and mortality of some introduced goat kids in a large-scale dairy goat farm in Inner Mongolia, so as to provide a scientific basis for this farm to strengthen the prevention and control of major epidemic diseases. [Method] The pathological anatomy obaservation of the diseased goat kids with typical clinical signs was made. Pathological sections were prepared using aseptically collected lung samples with lesions. Serum was prepared using aseptically collected blood samples, and the goatpox virus antibody in serum was detected by high-sensitive fluorescence technology. The lung tissues as well as nasal and eye swabs were aseptically gathered, and the P32 gene of goatpox virus was detected by PCR assay and sequenced. The obtained the sequences were subjected to comparision with BLAST and homology analysis. [Result] Pathological autopsy showed that there was round pox in oral, nasal, laryngeal, and tracheal mucosa of the diseased goat kids; the lungs were obviously edematous with red pox on the surface, and were opaque and gray-white jelly like following incision; pox was also visible in the rumen, reticulum, omasum, and abomasum mucosa. Histopathologic examination revealed that the alveoli were intensely stained with red; the alveolar interstitium was widened, and the alveolar cavity contained exfoliated epithelial cells; type Ⅱ alveolar epithelial cells proliferated and had a metaplasia into acinar-like shape; there were massive inflammatory cells in the lumen of bronchi. The goatpox virus antibody in serum of the diseased goat kids was tested positive using high-sensitive fluorescence technology. Lung tissue （GTPV-YP1）, nasal swab （GTPV-YP2） and eye swab （GTPV-YP3） samples were collected, and the P32 gene of a predicted length of 983 bp was all amplified by PCR assay from these samples. The P32 gene sequences of GTPV-YP1 and GTPV-YP2 samples had 100% homology with goatpox virus Chinese isolate KC951854.1 and Oman isolate MN072621.1, and the P32 gene sequence of GTPV-YP3 sample was 99.0% homologous to goatpox virus Chinese isolates EF514892.1, HM572329.1, JN596275.1 and MG817382.1. [Conclusion] The goatpox virus infection was determined as the cause of the illness in the introduced dairy goat kids on the farm by pathological anatomy observation, histological examination, serological detection, and pathogen PCR identification.