[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] 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.

[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.

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 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.

Atriplex canescens （A. canescens） shows stress resistance or tolerance to cold, drought, saline-alkali and barren. It has high biomass and exhibites strong adaptability when introduced and planted in various habitat in northern China. A. canescens can be used as improvement plant of saline land, high-quality feed and host of Cistanche deserticola, and it has a great developmental potential in northern China. On the basis of consulting a large number of literature, this paper analyzes and summarizes the feeding value of A. canescens, proposes that the future research should focus on the aspects of high yield cultivation, formula feed processing, and planting technology on saline-alkali soil land, in hoping to provide references for feed development and utilization of A. canescens.

[Objective] To characterize the microbial structure of litters at different depths in dairy cow fermentation bed, and to assess the application effect of fermentation bed in dairy cow raising. [Method] The number of colonies of three commonly observed pathogenic bacteria in litters with or without fermentation bed was compared. During a two-year monitoring period, the incidence of limb-hoof disease, milk yield, milk somatic cell count （SCC） of the dairy cows raised with or without application of fermentation bed were determined and compared. In addition, the total number of bacteria in raw milk produced by dairy cows using varied litter supplements （rice husk and dried cow feces residue, wood sawdust, rice husk powder) of fermentation bed were evaluated. After two-year period of application, the samples of litters at surface layer （at 5 cm）, middle layer （at 25 cm） and deep layer （at 45-50 cm） were collected and subjected to examination of basic physical and chemical indicators. The distributive characteristics of bacteria and fungi of litters at different depths in fermentation bed were analyzed by using 16S rDNA and ITS1 based high-throughput sequencing methods, respectively. The metabolic functions of the microbial community of the fermentation bed were predicted by bioinformatics software. [Result] The number of colonies of Escherichia coli, Streptococci and Klebsiella in litters with fermentation bed was lower than that in litters without fermentation bed. During the two-year monitoring period, the dairy cows raised with application of fermentation bed had lower incidence of limb-hoof disease, significantly （P<0.05） higher average milk yield, and reduced average SCC in raw milk compared with their counterparts without application of fermentation bed. The lowest total number of bacteria in raw milk was observed in the dairy cows using rice husk and dried cow feces residue as litter supplements. The basic physical and chemical parameters （temperature, water content, pH value, and concentrations of ammonia and hydrogen sulfide） of the fermentation bed with rice husk and dried cow feces residue as litter supplements still met the production needs after two-year continuous and stable application. The micro-ecological community of the fermentation bed was dominated by bacterial flora. Bacteroidetes and Firmicutes were mostly distributed in the middle and deep layers, and Actinobacteria were mostly distributed in the surface layer. The samples of litters at different depths in fermentation bed had similar fungal community composition, and most of the fungi were distributed in the deep layer after fermentation. KEGG pathway enrichment analysis demonstrated that the bacterial community had a greater impact on the entire micro-ecosystem of the fermentation bed. The bacterial metabolism in the litters was the most active, and there were still a large number of fungal genera to be further annotated and explained. [Conclusion] The health status of dairy cows and the quality of their raw milk have been improved by applying the fermentation bed technology.

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.

[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 better understand how dominant plants' leaf nutrient content and stoichiometric characteristics respond to varying grazing intensities in the desert steppe. [Method] On the grazing sample plots of Stipa breviflora desert steppe in Inner Mongolia, four treatments with varied grazing intensities were set up: control （CK）, light grazing （LG）, moderate grazing （MG）, and heavy grazing （HG）, with stocking rates of 0, 0.91, 1.82, and 2.71 sheep/hm² respectively. In the year of 2020, under varying grazing intensities, the concentrations of C, N, and P in leaves of domoinant plants Stipa breviflora, Cleistogenes songorica, Convolvulus ammannii and Artemisia frigida were measured, and their stoichiometric properties were calculated.[Result] Compare with CK group, heavy grazing significantly （P<0.05） decreased the leaf C concentration of Stipa breviflora and Convolvulus ammannii. Grazing had no significant （P>0.05） effect on the leaf N content of all four dominant plants tested. Moderate grazing significantly （P<0.05） increased the P concentration in the leaves of Stipa breviflora and Convolvulus ammannii, while significantly （P<0.05） decreased the P concentration of Artemisia frigida. Heave grazing significantly （P<0.05） decreased the C∶N of Convolvulus ammannii, the C∶P of Stipa breviflora, Convolvulus ammannii and Artemisia frigida as well as the N∶P of Stipa breviflora. [Conclusion] Grazing alters plants' nutrient utilization. Different plants have different adaptation strategies to the same habitat. Grazing reduces the C fixation capacity of dominant plants in desert steppe. Long-term moderate grazing promotes the absorption of N and P by dominating plants in desert steppe.

[Objective] To screen alfalfa varieties with higher nutritional value in Hinggan League, Inner Mongolia. [Method] Using 34 foreign alfalfa varieties as experimental materials, planting studies were carried out at Hinggan League, Inner Mongolia. The contents of crude protein, crude fat, crude ash, neutral detergent fiber and acid detergent fiber of the 34 varieties were measured.The relative feeding value were calculated, and the nutritional value was comprehensively evaluated by membership function method.[Result] Among the 34 alfalfa varieties tested, the highest contents of crude protein, crude fat, crude ash, neutral detergent fiber and acid detergent fiber were 'SK3010', 'Algonquin', 'Kangsai' and 'Challenger' respectively. 'Juneng 2' had the highest relative feeding value. The varieties with a superior overall evaluation using the membership function approach were 'Juneng 2', 'SK3010' and 'Algonquin'. [Conclusion] Among the 34 alfalfa varieties evaluated, 'Juneng 2', 'SK3010' and 'Algonquin' had higher promotion and utilization value in the cold and dry area of Hinggan League, Inner Mongolia.

[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.

[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.

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.

[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.

Since the implementation of the 'grain to feed' policy, the dairy industry has been revitalized through the adjustment of agricultural structure. However, since the global spread of novel coronavirus pneumonia outbreak, food safety has entered the public view again, and thus raised an issue worth thinking deeply: how to realize the forage-livestock balance, increase the market supply of meat, eggs and milk, as well as optimize the dietary and nutrition structure of residents under the premise of ensuring food security. Therefore, taking Hebei Province as the research object, an in-depth analysis on the grain, forage planting as well as market supply and demand were carried out. At present, the grain planting area in Hebei Province is above the 'red line', and forage production cannot meet the needs of the province's animal breeding industry. At the same time, the intake of meat, eggs, and milk by urban and rural residents still does not meet the dietary nutrition standards. In order to optimize the agricultural planting structure and the nutritional structure of residents, this study proposes a series of measures such as promoting new planting models, strengthening policy guidance, and innovate production technologies to propel the development of grain-feed balance in Hebei Province.

[Objective] To determine the pathogenic bacteria causing calf diarrhea in a cattle farm in Duolun County, Xilin Gol League, Inner Mongolia, and to provide a basis for selecting sensitive drugs to treat this disease. [Method] Anal swabs from calves with diarrhea were collected aseptically for bacterial isolation, identification, pathogenicity test and in vitro antimicrobial sensitivity test. [Result] The bacterial strains isolated from the anal swab samples had the consistent colony morphology. The isolates were confirmed as Escherichia coli （E. coli） by phenotypic identification, physiological and biochemical identification and 16S rDNA gene sequencing identification. The isolates were molecularly identified as ETEC type by using the E. coli typing primers. In addition, the E. coli isolates could cause mice death. The E. coli isolats were resistant to 21 antimicrobial agents such as ampicillin, aztreonam, cefazolin, tetracycline, ofloxacin, levofloxacin and compound trimethoprim, were moderately sensitive to 10 antimicrobial agents such as cefoperazone, ceftriaxone, clindamycin, polymyxin B and minocycline, and were sensitive to 4 antimicrobial agents such as cefoxitin, vancomycin, ciprofloxacin and nitrofurantoin. [Conclusion] The calf diarrhea in this cattle farm was caused by enterotoxigenic E. coli. Ciprofloxacin was recommended to be used in treatment of this disease.

[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.

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.

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.