[Objective] To further assess the potential anti-inflammatory and immunomodulatory roles of taurochenodeoxycholic acid （TCDCA）. [Method] The fibroblast-like synoviocytes （FLS） of adjuvant arthritis （AA） rats were used as experimental research objects. The contents of prostaglandin E₂（PGE₂） in supernatant of FLS co-incubated with TCDCA and IL-1β were determined by ELISA to evaluate the effect of TCDCA on PGE₂ excretion with stimulation of IL-1β. [Result] TCDCA significantly （P<0.05） reduced the PGE₂ excretion level with stimulation of IL-1β in FLS of AA rats. [Conclusion] TCDCA has inhibitory effect on PGE₂ excretion with stimulation of IL-1β in FLS of AA rats, which provides reference for application of TCDCA in veterinary clinic practice.

[Objective] To screen an enhanced expressed promoter with high stability using the known Lactobacillus plantarum promoter and the green fluorescent protein reporter gene, and to provide genetic element for construction of the highly efficient and specific expression vectors in Lactobacillus plantarum. [Method] The known Lactobacillus plantarum promoters of P11, Pefp, Ptuf33 and Ptuf34 as well as the corresponding downstream green fluorescent protein reporter genes were synthesized, respectively. To construct the promoter-screening vectors, the above synthesized sequences were used to replace the original multiple cloning sites and the corresponding upstream promoters of the pMG36e, a lactic acid bacteria expression vector, respectively. The successfully constructed promoter-screening vectors were transformed into Lactobacillus plantarum by electroporation, and the promoters were screened by detecting the strength of green fluorescent signal of recombinants. [Result] Among the four constructed promoters, Ptuf33 and Ptuf34, the promoters of transcription elongation factor TU gene, had significantly （P<0.05) higher expression levels in the target genes compared with the other two promoters. [Conclusion] In combination with the results obtained in this study and related reports, it is known that the promoters of Ptuf33 and Ptuf34 are generally highly expressed in Lactobacillus plantarum, and they can serve as the candidates for subsequent construction of highly expressed vectors in Lactobacillus plantarum.

[Objective] To characterize the genetic variations of S gene in vaccine strains and epidemic strains of porcine transmissible gastroenteritis virus （TGEV）. [Method] The S genes from the commonly used TGEV vaccine strains of A, B and C in China were cloned by RT-PCR assay and subsequently sequenced. The obtained sequences were genetically compared with the published S gene sequences of TGEV strains isolated from different regions in recent years. The S gene sequences from TGEV vaccine strains of A, B,C and TGEV epidemic strains published in NCBI with accession numbers of AF104420.1-Britain, AY587882.1-Nanjing, DQ811786.2-America, EU074218.2-Harbin, FJ755618.2-Harbin, JQ700304-fuzhou, KC609371.1-Shanghai, KX900411.1-United States, M94099.1-Spain and MK272773.1-Fushun were genetically assessed with MegAlign software. [Result] The homologies of S gene sequences among vaccine strains of A, B and C were all above 96.7%, and those among vaccine strains of A, B, C and the epidemic strains published in NCBI were 94.43%-99.82%, 95.30%-99.64% and 93.48%-98.38%, respectively. The phylogenetic trees demonstrated that vaccine strains of A and C as well as abroad epidemic strain of M94099.1-Spain were clustered in the same branch, and vaccine strain of B and domestic epidemic strain of JQ700304-fuzhou were clustered in another branch. [Conclusion] The S gene sequences of TGEV vaccine strains have high homologies with those of TGEV epidemic strains, indicating minor genetic variations in S gene sequences between vaccine strains and epidemic strains.

[Objective] To assess dietary supplementation of different proportions of alfalfa meal on reproductive performance and serum biochemical, antioxidant and immune indexes of sows during late gestation. [Method] Single-factor completely randomized block design was used in this study. According to the principle of similar parity, body condition and expected date of delivery, a total of 40 Yorkshire×Landrace sows in late gestation were randomly assigned into 4 groups with 10 individuals for each group. The basal diets of the experimental sows were supplemented with alfalfa meal at proportions of 0 （control group）, 5% （5% alfalfa meal group）, 10% （10% alfalfa meal group） and 15% （15% alfalfa meal group）, respectively. The formal experiment started on the 85^th d of gestation and finished after delivery. On the 111^th d of gestation, blood samples of the experimental sows were collected, and the serum biochemical, antioxidant and immune indexes were determined; the litter size and alive litter size of sows were recorded within 12 h of delivery, and the birth litter weight and birth individual weight of piglets were determined. [Result] The birth litter weight of piglets in 10% alfalfa meal group was significantly （P<0.05） higher than that in the remaining groups. The serum albumin content and albumin-globulin ratio in 10% alfalfa meal group were significantly （P<0.05） lower than those in control group, and the serum glucose contents in 5% and 10% alfalfa meal groups were significantly （P<0.05） higher than those in control group. 5% and 10% alfalfa meal groups had significantly （P<0.05） increased serum total antioxidant capacity compared with control group; 10% alfalfa meal group had significantly （P<0.05） decreased serum malondialdehyde content compared with the remaining groups; 10% alfalfa meal group had significantly （P<0.05） elevated serum glutathione peroxidase activity compared with control group; 10% alfalfa meal group had significantly （P<0.05） improved serum superoxide dismutase activity compared with the remaining groups, and 5% and 15% alfalfa meal groups had significantly （P<0.05） improved serum superoxide dismutase activity compared with control group. [Conclusion] Dietary supplementation of alfalfa meal has certain ameliorative effects on reproductive performance and serum biochemical, antioxidant and immune indexes of sows during late gestation, and the adding proportion of 10% is recommended.

[Objective] To assess the application effects of lemongrass meal as feed additive instead of antibiotics in Wenchang chickens feeding, and to explore new route for antibiotic-free feeding of Wenchang chickens. [Method] A total of 30 one-month-old Wenchang chickens were randomly divided into three groups, and there were 10 individuals with half males and half females in each group. The control group was fed with a basal diet, and the experimental groups 1 and 2 were fed with the basal diet supplemented with 3% lemongrass meal and 0.1% amoxicillin, respectively. The male and female Wenchang chickens were reared in separate cages. The experimental period lasted for 28 d. The daily feed intake was recorded, and the average daily weight gain and feed to gain ratio were calculated; the villus height and crypt depth of duodenum, jejunum and ileum were determined, and the corresponding villus height to crypt depth ratio （V/C） was calculated; the activities of serum total superoxide dismutase （T-SOD） and catalase （CAT） as well as the serum content of malondialdehyde （MDA） were determined. [Result] The average daily weight gains of experimental groups 1 and 2 were significantly （P<0.05） higher in comparison with control group, and there was no significant （P>0.05） difference between experimental group 1 and experimental group 2; no significant （P>0.05）differences in average daily feed intake and feed to gain ratio among different groups were observed. Compared with control group, the villus height of duodenum and jejunum as well as the V/C of jejunum in experimental groups 1 and 2 were significantly （P<0.05） increased, and there were no significant （P>0.05） differences between experimental group 1 and experimental group 2; no significant （P>0.05） differences in V/C of duodenum and ileum as well as villus height of ileum among different groups were found. Experimental group 1 had significantly （P<0.05） higher activity of serum CAT in comparison with control group and experimental group 2; no significant （P>0.05） differences in activities of serum T-SOD were observed among different groups; the serum contents of MDA in experimental groups 1 and 2 were significantly （P<0.05） lower in comparison with control group, and there was no significant （P>0.05） differences between experimental group 1 and experimental group 2. [Conclusion] Dietary supplementation of lemongrass meal improves the growth performance of Wenchang chickens, and has better growth promoting effect than antibiotics.

The ruminal and intestinal microorganisms in ruminants are in a complex microecosystem, and their diversity and nutritional metabolism are closely related to various factors in this system. Understanding the diversity variations and nutritional metabolism mechanisms of ruminal and intestinal microorganisms in ruminants is an important basis for improving animal welfare, animal production efficiency and animal product quality as well as reducing greenhouse gas emissions by human intervention. The relationship between diversity and nutritional metabolism of ruminal and intestinal microorganisms in ruminants and the individual environmental factor has been extensively studied and some advances have been achieved, which plays a certain role in guiding production practice and protecting the environment. This paper reviews the research advances on diversity of ruminal and intestinal microorganisms in ruminants in China and abroad in recent years, as well as interactions and corresponding mechanisms between microorganisms and host animals, diet structures and environmental factors, in hoping to provide references for exploring the roles and mechanisms of ruminal and intestinal microorganisms in nutritional metabolism in ruminants.

Influenced by the traditional view of′no acids, no ulcers′, scholars have paid increasing attentions to that whether acidifiers affect the health of pig stomach and promote the occurrence of gastric ulcer in nowadays when they have been widely used in feed and rearing ends of pig production. Due to the functional variations in different regions of pig stomach, and the occurrence frequency and mechanism of gastric ulcer are also significantly different. The occurrence mechanism of gastric ulcer in pigs is expounded from the aspects of gastric mucosa structure, gastric acid, pepsin and bile, and whether acidifiers aggravate the occurrence of gastric ulcer is reviewed, in hoping to provide references for the rational use of acidifiers.

Lead is a heavy metal pollutant and is extremely harmful to human and animal health. Many studies have found that bone is the important target organ of lead toxicity. Lead accumulates in bone after absorption in body which results in osteoporosis. In clinic, the damages of lead to bone are mainly evaluated by some biochemical indexes of bone metabolism such as PINP, OPG, β-CTX and CT. In recent years, studies have shown that biochemical indexes of bone metabolism revealed the bone metabolism state and bone conversion rate, which is of great significance for the differential diagnosis of osteoporosis. In this paper, the research advances on the effects of lead on biochemical indexes of bone metabolism are reviewed, in hoping to provide references for investigation of the molecular mechanism underlining the impacts of lead on bone metabolism.

Tan sheep mutton is characterized by good freshness and tenderness, minor mutton odour, rich nutrition, uniformly distributed fat, high protein content, and low cholesterol content. Accordingly, it is widely accepted by consumers in recent years. Many scholars have studied the factors affecting the quality of Tan sheep mutton from various aspects, and have found that the nutritional factors played an important role in regulating the quality of Tan sheep mutton. In this paper, the quality evaluation indicators of Tan sheep mutton and the effects of nutritional levels on Tan sheep mutton quality are reviewed, in hoping to provide references for scientific production of Tan sheep mutton and improvement of mutton quality.

[Objective] To ascertain the effects of improvement strategy on severely desertified grassland, and to provide references for management, development and rational use of grassland. [Method] From the year of 2015 to 2017, mixed seeding of 6 varieties of high-quality forages sowed with drilling method, including Medicago sativa, Astragalus adsurgens, Melilotus officinalis, Hedysarum laeve, Elymus dahuricus and Elymus sibiricus, were set in a severely desertified grassland area. Using free-grazing area as control, the plant species were investigated by chessboard-sampling method; the abundance, frequency, coverage, height and yield of the plants were determined; the CO₂ absorption rate, photosynthetic rate, transpiration rate and stomatal conductance of the plants were assessed and subjected to multivariate correlation analysis. Furthermore, the Shannon-Wiener diversity index of the plants was calculated, and the soil nutrient contents and electrical conductivity were determined. [Result] The number of plant species in severely desertified grassland increased from 14 before improvement （in the year of 2015） to 72, 83 and 97 in the years of 2018, 2019 and 2020 after improvement, respectively; compared with free-grazing area, the average abundance, frequency, coverage, height and yield of the forages in the improvement area were significantly （P<0.05） increased; this area had significantly （P<0.05） higher CO₂ absorption rate, photosynthetic rate, transpiration rate and stomatal conductance in comparison with free-grazing area, and there were significantly or extremely significantly positively correlations between transpiration rate and photosynthetic rate （P<0.05）, stomatal conductance and transpiration rate （P<0.05）, forage yield and photosynthetic rate （P<0.05）, as well as forage yield and transpiration rate （P<0.01）; significant （P<0.05） differences in Shannon-Wiener diversity index of the main forage species between improvement area and free-grazing area were observed; the soil contents of organic matter, available phosphorus and available potassium as well as soil electrical conductivity in improvement area were significantly （P<0.05） higher than those in free-grazing area. [Conclusion] After improvement, the severely desertified grassland has dramatically increased number of plant species, greatly improved forage production level and grassland ecological benefit, and significantly ameliorated soil nutrients.

[Objective] To assess the effects of different degrees of human disturbance on the occurrence dynamics of locusts on grasslands, and to provide references for grassland pest control.[Method] From May to August in the year of 2018, 3 investigation sample plots with mild, moderate and severe disturbance were set up in Xinghuo pasture, Yinlang pasture and Hongji pasture in Ranghulu District of Daqing City of Heilongjiang Province, respectively, to assess the locust species, common species, population densities and population variations with time. The locust population densities were investigated by quadrat method with insect three-dimensional mesh enclosures and quadrat frame. The combination of quadrat frame sampling and sweep net sampling methods were used in the species surveys which were carried out once a week with a total of 12 times.[Result] A total of 11 species of locusts were observed in the 3 investigation sample plots, and Oxya chinensis was the dominant species in the grasslands with different degrees of disturbance. The common species were Oxya chinensis, Dasyhippus barbipes, Pararcyptera microptera meridionalis, Epacromius coerulipes, Chorthippus albomarginatus, Acrida cinerea, Haplotropis brunneriana Saussure and Oedaleus infernalis Saussure. The species numbers of locusts in grasslands with severe, moderate and mild disturbance were 9, 10 and 10, respectively. The total population densities of locusts were in the order of severe disturbance （5.10 heads/m²） > moderate disturbance （4.66 heads/m²） > mild disturbance （3.37 heads/m²） with significant differences （P<0.05）. The population densities of Oxya chinensis, Epacromius coerulipes, Pararcyptera microptera meridionalis, pygmy grasshoppers and Oedaleus decorus asiaticus among the grasslands with different degrees of disturbance were significantly different （P<0.05）. From May to August, the locust population densities increased first and then decreased, and the presence of peak phase of locust population densities in grassland with severe disturbance was earlier than that in grassland with moderate and mild disturbance.[Conclusion] The dominant species of locusts in grasslands in Daqing City with three degrees of human disturbance is Oxya chinensis. Mild disturbance can significantly reduce the locust population densities and delays the arrival time of the peak phase of locusts number in grassland.

[Objective] To compare the effects of adding different compound bacterial agents on composting process of sheep manures. [Method] Four groups were set in this study. The blank group added no fermentation starters, the experimental group 1 was inoculated with the previously self-developed decomposing agent （NO.1）, the experimental group 2 was inoculated with the optimized decomposing agent （NO.2）, and the experimental group 3 was inoculated with a commercially available decomposing agent. The temperature, pH value, moisture content, E₄/E₆ value and seed germination index of the composts in each group were determined at different fermentation periods, and the apparent characteristics such as color, odor and state of composts were recorded. [Result] During the composting process, the temperature rise rate of experimental group 2 was faster than that of the other three groups, and the lowest temperature rise rate was observed in blank group. At 35^th d of fermentation, the moisture contents of the composts in experimental groups 1, 2, 3 and blank group reduced to 27.15%, 25.97%, 28.03% and 42.30%, respectively; the pH values of the composts in experimental groups 1, 2 and 3 were 8.03, 7.98 and 8.09, respectively, and the highest pH value （8.58） was found in blank group; the E₄/E₆ values of the composts in experimental groups 1, 2 and 3 were 2.35, 1.80 and 2.53, respectively, and all of them were lower than that of blank group （3.00）; the seed germination indexes of the composts in experimental groups 1, 2 and 3 were 94.5%, 108.5% and 101.3%, respectively, indicating that the composts in these groups were completely harmlessly treated （completely composted）; the seed germination index of the composts in blank group was 75.3%, indicating that the composts in blank group were incompletely composted. At the end of fermentation, the composts in the 3 experimental groups were dark brown colored and loose shaped with white hyphae, and had no odor, no attraction of mosquitoes and flies, and no parasitic eggs, which further indicated that the composts were completely composted; the composts in blank group were dull brown colored, had slight odor, rough hand-feeling, sporadic masses, attraction of mosquitoes and flies, and parasitic eggs were found in deep layer, which further indicated that the composts were incompletely composted. [Conclusion] Adding compound microbial agents accelerates the composting process of sheep manures and completes the harmless treatment in advance; inoculation with the optimized decomposing agent （NO.2） have the highest seed germination index and maturity of composts, and performs better in accelerating the composting process.

Antibiotics play an important role in preventing and therapying animal diseases, and can promote animal growth and development to a certain extent. The residual antibiotics in livestock and poultry manures not only cause environmental pollution, but also lead to the transmission and spread of antibiotic-resistant bacterial strains of animal origin in the environment, which pose a threat to public health security and human health. Reducing the residues of antibiotics in livestock and poultry manures by using high-efficient and convenient treatment methods can alleviate the ecological environment pollution to a certain extent. Traditional treatment methods include anaerobic digestion and aerobic composting, which can effectively reduce the residues of antibiotics in livestock and poultry manures. However, there are still some limits such as incomplete removal of antibiotics and high requirements for treatment conditions. In recent years, the application of black soldier fly （Hermetia illucens） larvae in treatment of residual antibiotics in livestock and poultry manures has attracted widely attention. In this paper, the commonly observed residual antibiotics in livestock and poultry manures are summarized. Furthermore, the removal efficiency of the traditional methods including anaerobic digestion and aerobic composting as well as the novel method using black soldier fly in treatment of residual antibiotics in livestock and poultry manures is analyzed, in hoping to provide references for research and application of treatment methods of residual antibiotics in livestock and poultry manures.

[Objective] To develop a liquid chromatography-tandem mass spectrometry （LC-MS/MS） method for simultaneous detection of colistin A and colistin B in mutton. [Method] The samples were extracted with 10% trichloroacetic acid aqueous solution-acetonitrile solution, and then the targets were purified and enriched with WCX solid phase extraction column. The targets were gradiently eluted using 0.1% formic acid aqueous solution as mobile phase with a flow rate of 0.3 mL/min. After screening by multiple reaction monitoring （MRM） under positive ion mode, the targets were detected by LC-MS/MS and were quantitatively determined by external standard method with addition of standard solution in matrix. [Result] Colistin A and colistin B had a good linear relationship in the range of 5.0-110.0 μg/L, and the linear correlation coefficients were above 0.996. The limit of quantitation of the developed LC-MS/MS method was 0.50 μg/kg. At three adding levels, the average recoveries ranged from 73.2% to 115.6% with relative standard deviations （RSD） ≤10.0%. [Conclusion] The developed LC-MS/MS method is highly efficient and accurate, and is applicable for quantitative and confirmatory determination of colistin A and colistin B in mutton samples.

Donkey milk is a treasure of purely natural milks and has health care effects on organs of human body. It not only has high nutritional value and medicinal value, but also has excellent effects on skin care and beauty. Donkey milk has become a favored raw material for cosmetics and therefore has a very broad prospect of development and application as a functional raw material ingredient for cosmetics production. This paper reviews the research advances on the major components, nutritional value and medicinal value of donkey milk as well as its application in cosmetics, in hoping to provide references for development and application of donkey milk in cosmetics and for establishment of a high value-added donkey milk industrial system.

[Objective] To analyze the effects of grassland ecological reward policy on total factor productivity （TFP） in animal husbandry of six main pastoral provinces and autonomous regions, and to compare the implement effects of first and second round grassland ecological reward policy. [Method] The animal husbandry data of six main pastoral provinces and autonomous regions from the year of 2007 to 2018 were used to calculate their corresponding TFP, and the effects of two rounds′ grassland ecological reward policy on TFP in animal husbandry of six main pastoral provinces and autonomous regions were analyzed, respectively; difference-in-difference model was used to evaluate and compare the implement effects of the first and second round grassland ecological reward policy. [Result] The grassland ecological reward policy had promotive effects on TFP in animal husbandry, and the TFP in animal husbandry was 0.101 and 0.137 increased through the implement of the first and second round grassland ecological reward policy, respectively. [Conclusion] While the grassland ecological reward policy is implemented by restricting grazing and controlling livestock population, it does not impede the development of animal husbandry; the second round grassland ecological reward policy has better implement effects in comparison with the first round.

[Objective] To accurately grasp the research directions of beef cattle industry in China, and to promote the systematization, specialization and precision of beef cattle industry researches. [Method] The original data of 2 389 published scientific articles on beef cattle industry in CNKI Journal Database from the year of 2000 to 2020 were taken as the analysis objects. CiteSpace software was used to summarize and analyze the publication time, authors, institutions, journals, highly cited references and co-occurrence, clustering, time zone and emergence of the keywords of the articles. [Result] The number of published articles on beef cattle industry in scientific journals had dramatically increased since the year of 2009. CAO Bing-hai, ZHANG Yue-jie and ZAN Lin-sen and other scholars made a lot of researches on beef cattle industry, while the cooperation among the scholars was scattered. Jilin Agricultural University, Northwest Agricultural and Forestry University, Chinese Academy of Agricultural Sciences and China Agricultural University were the dominant contributive institutes; there were limited collaborations and connections among different institutes, and cross-regional and cross-sectoral cooperation was expected to be enhanced. Journal of Animal Science and Veterinary Medicine published the most articles on beef cattle industry; Chinese Rural Economy had the highest impact factor among the journals which had published articles on beef cattle industry; Beef Cattle Breeders: Factors Affecting Their Choice for Ways of Vertical Cooperation was the most frequently cited article. [Conclusion] The comprehensiveness of the researches on beef cattle industry in China has continuously escalated, the academic recognition and value have steadily improved, and the research hotspots mainly focus in beef cattle industry, beef cattle feeding, beef cattle breeds, etc.

[Objective] To assess the effects of insemination depth and time on conception rate of Mongolian sheep inseminated with frozen semen. [Method] Health Mongolian ewes with normal reproductive capacity were chosen as experimental animals and were subjected to estrus synchronization using progesterone sponges. The ewes were artificially inseminated with frozen semen after estrus using conventional artificial insemination method （n=135）, transcervical insemination method [transcervical first fold （1-2 cm） insemination （n=120）, and transcervical second to third fold （3-4 cm） insemination （n=120）] , and laparoscopically assisted intrauterine insemination method （n=128）, respectively. The recipient ewes receiving conventional artificial insemination and transcervical insemination were separately inseminated once around 14 h and 22 h after estrus, and those receiving laparoscopically assisted intrauterine insemination were inseminated once during 30 h to 36 h after estrus. B-ultrosonic examination was carried out at 40 d after insemination, and the conception rates of the ewes inseminated by different methods were calculated and statistically compared. [Result] The highest average conception rate was observed in the ewes receiving laparoscopically assisted intrauterine insemination （60.2%）, followed by those receiving transcervical second to third fold （3-4 cm） insemination （58.3%）; the average conception rates of the ewes receiving transcervical first fold （1-2 cm） insemination and conventional artificial insemination were 37.5% and 36.3%, respectively. The statistical analysis demonstrated that the average conception rates of the ewes receiving laparoscopically assisted intrauterine insemination and transcervical second to third fold （3-4 cm） insemination were significantly （P<0.05） higher than those of the ewes receiving conventional artificial insemination and transcervical first fold （1-2 cm） insemination. [Conclusion] For Mongolian ewes, laparoscopically assisted intrauterine insemination method （inseminated once during 30 h to 36 h after estrus） that completely penetrates cervix obtains higher conception rate in comparison with conventional artificial insemination method; transcervical insemination method （separately inseminated once around 14 h and 22 h after estrus） with depth of nearing 4 cm achieves similar conception rate to laparoscopically assisted intrauterine insemination method.

Artificial intelligence （AI） technology is an important new force in emerging scientific and technological revolution as well as animal husbandry revolution. It plays a vital role in realizing the digitalization, informatization and intellectualization of animal husbandry in China. The wide application of AI technology in animal husbandry will provide new insights into the resolution of the major and core problems in animal feeding such as disease prevention, precision treatment, precision nutrition, biosafety control and intelligent weighing, and will also become a powerful booster to accelerate the modernization of animal husbandry. With the help of universal application of key AI technology, realizing refinement, securitization, automation, intellectualization and digitalization of the whole animal husbandry chain and thereby improving the overall management capacity of animal husbandry will become an effective way to facilitate the development of intelligent animal husbandry. In this paper, a review is provided in the following aspects: developmental process of AI, application of AI in livestock and poultry breeding, AI practices in animal husbandry enterprises, and development and application trend of AI technology in animal husbandry, in hoping to provide references for promoting the wide application of AI technology in the whole animal husbandry chain.

[Objective] To investigate the effects of castration on serum antioxidant indexes in male dogs. [Method] A total of 12 healthy male Chinese rural dogs aged around one year were randomly assigned into a control group or a castration group with 6 dogs per group. The formal experiment was performed after a 5-day pre-feeding period. At the initial of the experiment, blood samples of the experimental dogs were collected. The testectomy was performed in the dogs in castration group, and the dogs in control group received no testectomy. The blood samples of the experimental dogs were collected on 5^th, 10^th and 15^th days after testectomy, and the serums were obtained by centrifugation. The activities of superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px） as well as the contents of hydrogen peroxide （H₂O₂） and malonaldehyde （MDA） in serums of the dogs in castration group and control group were determined and statistically compared. [Result] No significant （P>0.05） differences in serum SOD activities between control group and castration group were observed. On 5^th, 10^th and 15^th days after testectomy, the serum GSH-Px activities of castration group were significantly （P<0.05） lower than those of control group. Castration group had extremely significantly （P<0.01） higher serum contents of MDA and H₂O₂ on 10^th and 15^th days after testectomy compared with control group. [Conclusion] Castration has no significant effect on the serum SOD activities of male dogs, but significantly reduces the serum GSH-Px activities and elevates the serum contents of MDA and H₂O₂.

Mongolia, bordering Inner Mongolia Autonomous Region of China, has a large number of livestock, and is known as the′Animal Husbandry Kingdom′. Natural grazing is the main type of livestock feeding in Mongolia. Understanding the situation of prevention and control of foot-and-mouth disease in Mongolia can lay the foundation for prevention of foreign animal epidemic diseases invasion as well as for scientific prevent and control of the epidemics in China. We have analyzed the data from the World Organization for Animal Health （OIE） from the year of 2015 to 2020 and the recent materials of foot-and-mouth disease prevention and control in Mongolia, and found that the foot-and-mouth disease epidemic situation in Mongolia has generally increased first and then decreased during the year of 2015 to 2020, and there is no reports of foot-and-mouth disease epidemic in the years of 2019 and 2020. It is indicated that Mongolia has effectively controlled the foot-and-mouth disease epidemic in its territory in recent years by improving the relevant laws and regulations for prevention and control of animal epidemic diseases, combing veterinary management systems, and enhancing the laboratory test capabilities. It is recommended that China and Mongolia should strengthen the cooperation in the field of veterinary medicine. On one hand, it can reduce the risks of cross-border transmission of foot-and-mouth disease from the border areas of Mongolia to Inner Mongolia Autonomous Region of China. On the other hand, it can originally control the food safety risks and promote the orderly import of Mongolian beef and mutton to meet the growing demands of the domestic market of China on the premise that the trade is in compliance with the international and domestic rules and regulations.