[Objective] To investigate the underlining molecular mechanism of porcine deltacoronavirus （PDCoV） invading the host cells, the structure and function of the protein that served as a specific receptor of PDCoV and encoded by the aminopeptidase N gene （pAPN） was bioinformatically analyzed. [Method] A variety of bioinformatic software was used to predict and assess the physical and chemical properties, hydrophilicity and hydrophobicity, signal peptide, transmembrane domain, glycosylation site,antigenic epitope, functional domain, and structural characteristics of pAPN protein. [Result] The total length of pAPN gene is 2 892 bp, which encodes 963 amino acids. Among them, the 35^th~963^th amino acids are the extramembrane protein region, which do not contain signal peptide but contain two typical functional domains. pAPN protein contains 23 glycosylation modification sites and 42 antigenic epitopes. The spatial structure of extracellular domain of pAPN protein is a dimer, and each monomer can be divided into four domains of Ⅰ~Ⅳ. [Conclusion] This study provides information for understanding the molecular mechanism of interactions between pAPN protein and various porcine enteric coronaviruses.

[Objective] To evaluate the acute toxicity of Jieshitong tablet in mice, to observe its diuretic effect on healthy rats, and to assess its alleviating effect on oxalamide-induced renal calculi in rats. [Method] A total of 40 ICR mice （half females and half males） were selected and randomly divided into a control group and an administration group with 20 mice in each group. The weight changes and deaths of the mice before and after the administration of Jieshitong tablet were observed. In addition, a total of 36 SD rats （half females and half males） were divided into normal saline group （n=12）, low-dose administration group （n=12, 5% Jieshitong tablet solution） and high-dose administration group （n=12, 10% Jieshitong tablet solution）. The 24-hour urine output of the rats in each group was counted. Another 42 male SD rats were used to investigate the effect of Jieshitong tablet on body weights, kidney weights and kidney to weight ratio of rats after treatment of oxalamide （2% mixed feeding）. [Result] During the 7 consecutive days after the administration of Jieshitong tablet solution, there was no obvious abnormality in the physiological activities of the mice, and no significant （P>0.05） difference in body weights between the control group and the administration group was observed. Compared with the normal saline group, the urinary volumes of the two administration groups were significantly （P<0.01) increased within 24 hours after administration of Jieshitong tablet solution. Compared with the oxalamide-induced renal calculi model group, the number of crystals and calculi in the Jieshitong tablet administration groups was significantly （P<0.01 or P<0.001） reduced with the increase of administration dose, and the number of rats that formed renal calculi was significantly （P<0.01 or P<0.001） reduced. [Conclusion] Jieshitong tablet has no obvious acute toxicity to mice, has obvious inhibitive effect in rats, and has obvious inhibitive effect on oxalamide-induced renal calculi in rats.

[Objective] To investigate the effects of different forms of iron and selenium supplementation for sows and piglets on growth performance, blood biochemical parameters and immune performance of piglets. [Method] Thirty-two sows were randomly divided into 8 groups with 4 individuals in each group. The sows in groups 1-4 received the dietary supplementation of ferrous sulfate and sodium selenite, and those in groups 5-8 received the dietary supplementation of iron glycine chelate and selenomethionine. The piglets produced by sows in groups 2 and 6 were intramuscularly injected with iron and selenium mixture on the 3^rd day after birth, those in groups 3 and 7 received the dietary supplementation of ferrous sulfate and sodium selenite, and those in groups 4 and 8 received the dietary supplementation of iron glycine chelate and selenomethionine. The piglets in groups 1 and 5 fed a basal diet and received no supplementation of iron and selenium. Sows were fed with the experimental diets from the 30^th day before the expected date of delivery, and piglets were fed with the experimental diets from the 7^th day after birth. The experiment was finished on the day of weaning of the piglets （21^th day after birth）. The growth performance indexes, blood biochemical parameters and immune function indicators of the piglets in different groups were determined and statistically analyzed, and the contents of iron and selenium in colostrum and normal milk of the sows were statistically compared. [Result] Based on the same form of iron and selenium supplementation for piglets, compared with the dietary supplementation of ferrous sulfate and sodium selenite （groups 1-4） for sows, the dietary supplementation of iron glycinate chelate and selenomethionine （groups 5-8） in the basal diet of sows significantly （P<0.05） or extremely significantly （P<0.01） elevated the birth weight, weaning weight, weaning survival rate, weaning qualification rate of the piglets, increased the contents of plasma iron, plasma selenium, hemoglobin, plasma transferrin, IgA, IgG and IgM of the piglets at 2 and 21 days of age, and improved the contents of iron and selenium in sows′ colostrum and normal milk. In both forms of iron and selenium supplementation for sows, compared with no supplementation of iron and selenium, different forms of iron and selenium supplementation （groups 2-4 compared with group 1, groups 6-8 compared with group 5） for piglets extremely significantly （P<0.01） increased the weaning weight, weaning survival rate and weaning qualification rate of the piglets, and also extremely significantly （P<0.01） elevated the contents or activity of plasma iron, plasma selenium, hemoglobin, plasma transferrin, glutathione peroxidase, IgA, IgG and IgM of the piglets at 21 days of age. In addition, the dietary supplementation of iron glycine chelate and selenomethionine for piglets had better performance than the other two forms of iron and selenium supplementation for the piglets. [Conclusion] Dietary supplementation of iron glycine chelate and selenomethionine for sows and piglets effectively improves growth performance, blood biochemical parameters and immune performance of piglets.

[Objective] To develop a rapid determination method for tryptophan in feed by microwave hydrolysis and amino acid automatic analyzer. [Method] The optimum conditions of microwave alkaline hydrolysis were screened by single factor test and orthogonal test, and the tryptophan content in total mixed ration （TMR） of dairy cow was determined by the LCAK06/Na （4.6 mm×150 mm) column of automatic amino acid analyzer. [Result] Hydrolysis temperature was the most important factor affecting tryptophan content in feed. The optimum conditions for determination of tryptophan in feed by microwave alkaline hydrolysis were as follows: hydrolysis temperature 170 ℃, hydrolysis time 30 min, alkali concentration 5 mol/L. The tryptophan content in TMR was 0.14% determined by amino acid automatic analyzer. The linear range of tryptophan was 0.025-0.60 μmol/mL, and the correlation coefficient （r） was 0.999 7. The limit of quantification （LOQ） was 0.05%, the recovery rate of tryptophan was 93%-104%, and the RSD of precision was 3.58%. [Conclusion] The developed method is efficient and accurate, and there is no significant difference in detection results between this method and the conventional hydrolysis method in the national recommended standard of ′Determination of Tryptophan in Feed′ （GB/T 15400-2018）, which has reference value for determination of tryptophan in feed.

[Objective] To investigate the effects of adding Pediococcus acidilactici （P. acidilactici） and Lactobacillus brevis （L. brevis） on fermentative quality and aerobic stability of corn and ryegrass silage. [Method] Experimental strains of P. acidilactici and L. brevis were isolated from fermented TMR. Thirty-day-long silage fermentation trials using whole plant corn and ryegrass were conducted by setting four treatment groups, including control group （adding tap water）, PA group （adding P. acidilactici）, LB group （adding L. brevis） and PA + LB group （simultaneously adding P. acidilactici and L. brevis）. After the sealed silage was opened, the indicators associated with silage quality, such as pH value, lactic acid content, acetic acid content, and the number of lactic acid bacteria and yeasts were determined, and the aerobic stability test was carried out. [Result] For corn silage, after a 30-day-long fermentation, no significant （P>0.05） differences in pH value and lactic acid content among the four treatment groups were observed; the contents of acetic acid in LB group and PA + LB group were significantly （P<0.05） higher than that in control group, and the numbers of lactic acid bacteria in PA group and PA + LB group were significantly（P<0.05） higher than that in control group; in the aerobic stability test, the spoilage of corn silage in PA + LB group was observed after 5 days of opening, and those in the other groups were observed within 2.5 days after opening. For ryegrass silage, after a 30-day-long fermentation, the pH values and ethanol contents in the experimental groups added with lactic acid bacteria were significantly （P<0.05） lower than those in control group, and the lactic acid content was significantly （P<0.05） higher than that in control group with the highest value in PA group; in the aerobic stability test, except for control group, the spoilage of ryegrass silage in the experimental groups added with lactic acid bacteria was observed after 7 days of opening, the lactic acid content in PA + LB group was the highest, and the acetic acid content in PA + LB group was significantly （P<0.05） lower than that in LB group. [Conclusion] Single addition of P. acidilactici or L. brevis has no significant effect on quality and aerobic stability of corn silage, and the combinative addition of P. acidilactici and L. brevis has no significant improvement in fermentative quality of corn silage, but improved its aerobic stability. Addition of lactic acid bacteria improves the fermentative quality and aerobic stability of ryegrass silage, and addition of P. acidilactici has the best performance in improving the fermentative quality. Furthermore, the combinative addition of P. acidilactici and L. brevis not only improves aerobic stability of ryegrass silage, but also improve its fermentative quality.

[Objective] To assess the effect of extruded straw microbial fermented feed on ruminal fermentation of Dorper × Thin-tailed Han crossbred sheep using roughage as single factor variable. [Method] A total of 81 3-month-old Dorper × Thin-tailed Han crossbred lambs weighed （23±1.0） kg were selected, and were randomly divided into control group （70% concentrate + 30% dry straw）, experimental group Ⅰ （70% concentrate + 30% extruded straw microbial fermented feed） and experimental group Ⅱ （70% concentrate + 30% extruded straw microbial fermented feed, and then adding extruded sustained release urea accounting for 10% of dietary total protein concentration, NPN≥100%). There were 3 replicates for each group and 9 crossbred lambs for each replicate. The experimental period lasted for 75 days, including 15 days of pre-feeding and 60 days of formal feeding. [Result] The concentrations of ammoniacal nitrogen （NH₃-N） and bacterial protein （BCP） in experimental group Ⅱ were significantly （P<0.05） higher than those in experimental group Ⅰ and control group, while there was no significant （P>0.05） difference between experimental group Ⅰ and control group. No significant （P>0.05） inter-group differences in volatile fatty acid （VFA） associated indicators were observed in paired comparisons. [Conclusion] The extruded straw microbial fermented feed + NPN have a promoting effect on ruminal fermentation.

[Objective] To investigate the effects of dietary supplementation of γ-polyglutamic acid on serum biochemical parameters of weaned calves. [Method] A total of 16 weaned Holstein calves with similar weights were divided into control group and experimental group with 8 calves in each group according to the principle of homogeneity. Calves in the two groups were fed with 3 kg pellet feed per head per day, and corn stover was fed ad libitum. In the experimental group, γ-polyglutamic acid （pasted liquid, containing 20% γ-polyglutamic acid） was added to the pellet feed at the rate of 5 ‰. The experiment lasted for 70 days, including a 10-day-long pre-experimental period and a 60-day-long formal experimental period. Blood samples were collected on the last day of the trial to determine the serum biochemical parameters. [Result] The serum levels of IgG, IgA and IgM as well as the activities of serum SOD and GSH-Px of the control group were significantly （P<0.05） higher than those of the experimental group. There was no significant （P>0.05） difference in activities of AST and ALT between the control group and the experimental group. No significant （P>0.05） differences in serum contents of TP, ALB, BUN, NEFA, GLU, Ca, P, Fe and Zn between the control group and the experimental group were observed, while the serum contents of Cu, VA and VC of the experimental group were significantly （P<0.05） lower than those of the control group. [Conclusion] For weaned Holstein calves, dietary supplementation of γ-polyglutamic acid reduces their serum contents of immunoglobulin (IgG, IgM, IgA), has the potential to improve their antioxidant capacity, promotes their absorption and utilization of Cu, VA and VC, and exhibits no negative effects on their liver function, energy metabolism, energy balance and protein utilization.

[Objective] To select the formula of native grass based total mixed ration pellets for fattening mutton sheep. [Method] Taking native grass as roughage, maize meal, soybean cake and wheat skin as concentrate, salt and premix as feed additive, and by referring to the ′Feeding Standard of Meat-producing Sheep and Goats′（NY/T 816-2004）, an agricultural industry recommended standard of China, formulas of total mixed ration were designed on the basis of setting native hay accounting for 50% （formula 1）, 60% （formula 2） and 70 % （formula 3） of the feed intake. Then pellets of total mixed ration were prepared. By analyzing the nutrient composition and in vitro dry matter digestibility （IVDMD） of different formulas, the optimum formula of native grass-type total mixed ration pellets for fattening mutton sheep was selected. [Result] The crude protein （CP） contents in formula 2 and formula 3 were significantly （P<0.05） higher than that in formula 1. The contents of neutral detergent fiber （NDF） and acid detergent fiber （ADF） in formula 2 and 3 were significantly （P<0.05） lower than those in formula 1,while the IVDMD in formula 2 was significantly （P<0.05） higher than that in formula 1 and 3. [Conclusion] For fattening sheep with a weight of 25 kg and a daily gain of 0.45 kg, the native grass-type total mixed ration pellets with native hay accounting for 60% of the feed intake （formula 2） is the best.

[Objective] To clarify the comprehensive performances of quality traits of different silage maize varieties, and to discovery the excellent gene sources of silage maizes. [Method] The correlation analysis of 26 quality traits of 8 silage maize varieties was performed. [Result] These tested traits could be divided into two categories, including nutritional value indicators and morphogenetic factors. The coordination and unification of these two types of traits were the most basic scales for selective breeding of high-quality silage maize varieties. The variety of LY19 had obvious advantages in morphogenetic traits, while the variety of 16X259 had outstanding predominance in nutritional value traits. [Conclusion] The variety of 16X259 reaches a good balance between nutritional values and morphogenetic traits, and has potential to serve as a high-quality variety for silage preparation; nutritive values and morphologic traits can be used as dominant gene sources for innovation and utilization.

Zinc is one of the essential microelements and plays an improtant role in growth and development of animals. As the organic microelement, zinc glycine has high bioavailability, and its application in animal production has some advantages in metal element emission reduction and environmental protection. In this paper, the effects of zinc glycine on the growth and reproductive performance, immunity and intestinal health of animals were summarized, and the requirement amount of zinc glycine for animals were discussed, in hoping to provide theoretical basis for scientific utilization of zinc glycine to improve animal health and promote animal growth in practical animal production.

[Objective] To investigate the growth and development rules of chicks of Hy-Line Brown laying hens and Jingfen No.2 laying hens under the identical rearing condition, and to assess their first egg qualities. [Method] A total of 1 000 chicks of 1-day-old Hy-Line Brown laying hens （n=500） and 1-day-old Jingfen No.2 laying hens （n=500） were selected and reared under the same condition. Sixty individuals of each laying hen breed were randomly chosen every week to measure their body weights until the 13 weeks of age （the end of the experiment）. Three curve models, including Logistic, Gompertz and Von Bertalanffy, were used to fit the growth and development of the chicks of both breeds. About 30 days after moving into coops, the experimental hens were monitored for starting of egg-laying, and the first eggs of both breeds were collected to determine and compare the quality indexes. [Result] The chicks of both breeds got the fastest growth rate during the 4-5 weeks of age. The used curve models as Logistic, Gompertz and Von Bertalanffy were all well fitting for the body mass data of both breeds, among which, Gompertz had the best performance due to its higher degree of fitting and better suitability. In the comparison of first egg qualities, all parameters of Hy-Line Brown laying hens were significantly higher （P<0.05） than those of Jingfen No.2 laying hens except for egg width and egg shape index. [Conclusion] These findings may provide referential data for the development, utilization and breed improvement of Hy-Line Brown laying hens and Jingfen No.2 laying hens.

[Objective] To assess the effect of early weaning on contents of amino acids and fatty acids in longissimus dorsi of Tibet cashmere goats. [Method] A total of 18 healthy goat lambs were randomly divided into two groups according to the principle of weight similarity. The lambs in the early weaning group were weaned on the 28 days of age, and those in the normal weaning group were weaned on the 60 days of age. All of the lambs were fed with the same milk replacer until the 75 days of age after weaning. Five lambs were randomly selected and slaughtered from each group for sampling, and then the indicators of amino acids and fatty acids in longissimus dorsi were determined and statistically analyzed. [Result] A total of 17 kinds of amino acids were found in longissimus dorsi of Tibet cashmere goats, including 7 kinds of essential amino acids such as lysine and leucine, and 10 kinds of non-essential amino acids such as aspartic acid and arginine. There were no significant （P>0.05） differences in contents of total amino acids, essential amino acids and non-essential amino acids between the early weaning group and the normal weaning group, while the EAA/TAA and EAA/NEAA in the early weaning group were significantly （P<0.05） higher than those in the normal weaning group. A total of 29 kinds of saturated and unsaturated fatty acids were detected, among which, the contents of palmitic acid and oleic acid were the highest. No significant （P>0.05） differences in contents of saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids between the early weaning group and the normal weaning group were observed. [Conclusion] The meat of Tibet cashmere goat lamb has good performance in composition and contents of amino acids and fatty acids. Early weaning and early supplementation of pellet feed have no effects on contents of amino acids and fatty acids in lamb meat, and can increase the value of EAA/TAA and EAA/NEAA, making it more consistent with the FAO/WHO amino acid scoring pattern. This study may provide references for applying early weaning in Tibet cashmere goat lamb and improving reproductive rate of the ewes.

[Objective] To assess the effects of different planting densities and different livestock and poultry manures as base fertilizer on agronomic traits and sugar content of feeding sweet sorghum. [Method] A two-factor randomized block designed trial using ′Liaotian′ sweet sorghum as experimental material was conducted. Five treatments including CK, normal fertilizer （NF） group, chicken manure （CM） group, pig manure （PM） group and sheep manure （SM） group were set with three levels of row spacing （45 cm, 50 cm, 55 cm） for each group. The NF group was applied 150 kg/hm² urea, the CM group, PM group and SM group were applied 15 t/hm² corresponding manures as base fertilizer respectively, and no fertilizer was applied in CK. At the harvest time, five plants of sweet sorghum were sampled from each plot to determine and compare their agronomic traits and sugar content under the conditions of different planting densities and different livestock and poultry manures as base fertilizer. [Result] When the chicken manures were used as base fertilizer, there were no significant （P>0.05） differences in agronomic traits and sugar content of sweet sorghum between different planting densities. When the sheep manures were used as base fertilizer, extremely significantly （P<0.01） higher plant height, leaf length, stem weight, stem length and sugar content were observed under the row spacing of 45 cm compared with those under the row spacing of 55 cm, and significantly （P<0.05） higher leaf area and fresh weight per plant were also observed. When the swine manures were used as base fertilizer, significantly （P<0.05） higher leaf length and chlorophyll content were observed under the row spacing of 45 cm compared with those under the row spacing of 55 cm. When the row spacing was 45 cm, the SM group had extremely significantly （P<0.01） higher plant height, leaf number and stem length compared with those of the CM group, and had significantly （P<0.05） higher leaf area compared with that of the CM group and the PM group. When the row spacing was 50 cm, the withered leaf number of the SM group was extremely significantly （P<0.01） higher than that of the other groups. When the row spacing was 55 cm, there were no significant （P>0.05） differences in plant height, leaf length, leaf number, stem diameter, stem weight, stem length, node number, fresh weight per plant and sugar content among the SM group, CM group and PM group. [Conclusion] The agronomic traits and sugar content of feeding sweet sorghum are the most significantly improved under the row spacing of 45 cm. When the sheep manures are used as base fertilizer, the feeding sweet sorghum has the best performance in agronomic traits and sugar content.

[Objective] To determine the optimal fertilization scheme for alfalfa cultivation and to improve its production performance and nutritional quality. [Method] The alfalfa variety of Medicago sativa L. cv. Zhongmu No. 2 was used as experimental material, chemical fertilizer and different kinds of organic fertilizer （farmmade organic fertilizer, vermicompost fertilizer, commercial organic fertilizer） were used as experimental fertilizer. A total of fourteen treatments were included: 1-4 treatments received single application of chemical fertilizer or different kinds of organic fertilizer, 5-7 treatments received combinative application of 1/2 chemical fertilizer and 1/2 different kinds of organic fertilizer, 8-10 treatments received combinative application of 1/2 chemical fertilizer and different kinds of organic fertilizer, 11-13 treatments received combinative application of 1/2 chemical fertilizer and 2 times different organic fertilizer. No fertilizer was used for the control treatment （CK）. There were 3 replicates （plots） for each treatment, and a total of 42 plots were included. The growth and nutritional quality of alfalfa of three cutting times were measured and compared under different fertilization treatments. [Result] Under three cutting times, compared with CK, different fertilization treatments （1-13） significantly （P<0.05） improved the hay yield, plant height, soluble sugar content, total chlorophyll content and crude protein content of alfalfa, and significantly （P<0.05） reduced the neutral detergent fiber content and acid detergent fiber content. Except that the treatment 4 in the first cutting did not reach the significant level, the relative feeding value of alfalfa of different fertilization treatments was all significantly （P<0.05） higher than that of CK. In the first cutting, the improvement effect of 1/2 chemical fertilizer + farmmade organic fertilizer （treatment 8） on growth and nutritional quality of alfalfa was only second to that of chemical fertilizer （treatment 1）. In the second cutting, treatment 8 had the best improvement effect on growth and nutritional quality of alfalfa. The hay yield, plant height, soluble sugar content, total chlorophyll content, crude protein content and relative feed value of treatment 8 were significantly （P<0.05） higher than those of the other treatments, and the neutral detergent fiber content and acid detergent fiber content of treatment 8 were significantly （P<0.05） lower than those of the other treatments. [Conclusion] Taking the improvement effects of different fertilization ratios on middle- and late-stage growth and nutritional quality of alfalfa as well as chemical fertilizer application reduction into consideration, 1/2 fertilizer + homemade organic fertilizer is recommended as the optimal fertilization scheme.

Otog Banner′ s government introduced ′High-quality Developmental Program of Premium Beef Cattle Industry in Otog Banner （2020-2022）′ in the year of 2020 to accelerate the development of local beef cattle farming industry. With the further optimization of animal husbandry structure and the implementation of strategies of rural revitalization, the development of premium beef cattle industry is imminent. In order to assist the development of premium beef cattle industry in Otog Banner and to exert the supportive roles of science and technology of agriculture and animal husbandry in Inner Mongolia, this paper conducts a comprehensive survey of the current situation of beef cattle industry in Otog Banner aiming at finding and solving problems, in hoping to provide references for local beef cattle farmers and industrial practitioners as well as for local government and policy makers.

In order to speed up the work of ′Grain to Forage′ in agricultural and pastoral ecotone in China and to improve the yield and quality of forage grass, by using the public information platform, the literatures on current situation and existing problems of forage grass production in China and abroad were retrieved and reviewed, and the domestic forage grass production status, supply and demand situation as well as corresponding countermeasures were analyzed. Based on the ′Grain to Forage′ subsidy policy and forage grass production status, the necessity of developing high-quality forage grass was discussed, and the development strategies, and suggestions for the production of high-quality forage grass in the future were put forward, in hoping to provide references for the sustainable development of herbivorous animal husbandry and the win-win development of planting and livestock farming industry.

[Objective] To explore the variation characteristics of trace elements and nutrients contents of forage grasses and main dominant forage grasses in desert steppe under different grazing intensities. [Method] Field investigations were conducted in areas with different grazing intensities （moderate grazing area, no-grazing area and heavy grazing area） in desert steppe in Otog Banner, Ordos City, Inner Mongolia Autonomous Region for 3 consecutive years. Combined with laboratory analysis, the effects of different grazing intensities on the contents of trace element and nutrient of forage grasses and three kinds of main dominant forage grasses （Cleistogenes songorica, Allium mongolicum, Stipa breviflora） in desert steppe were assessed. [Result] The selenium content of Cleistogenes songorica and Allium mongolicum as well as the copper content of forage grasses in moderate grazing area were significantly （P<0.05） higher than those in no-grazing area and heavy grazing area, and the selenium and copper contents of forage grasses in no-grazing area and heavy grazing area were nearly equal to or lower than the safe content standard in this region. The iron content of Allium mongolicum in moderate grazing area was significantly （P<0.05) higher than that in no-grazing area. The magnesium content of forage grasses in heavy grazing area was significantly （P<0.05) higher than that in no-grazing area and moderate grazing area, and exceeded the safety content standard in this region. The sodium content of Stipa breviflora, Cleistogenes songorica and Allium mongolicum in moderate grazing area was significantly （P<0.05) higher than that in no-grazing area and heavy grazing area. The contents of crude protein, crude fat, crude ash, phosphorus and calcium of forage grasses in moderate grazing area were higher than those in no-grazing area by 60.71%, 69.00%, 47.62%, 28.57% and 347.85%, respectively. The contents of crude fiber, neutral detergent fiber and acid detergent fiber of forage grasses in moderate grazing area were lower than those in no-grazing area by 13.93%, 24.80% and 6.35%, respectively. The crude protein content of Stipa breviflora in moderate grazing area was higher than that in no-grazing area by 11.50%. The contents of crude fat, crude ash and calcium of Cleistogenes songorica in moderate grazing area was higher than those in no-grazing area by 24.12%, 87.56% and 116.86%, respectively. The calcium content of Allium mongolicum in moderate grazing area was higher than that in no-grazing area by 24.03%. [Conclusion] Due to the long-term grazing prohibition and overgrazing, the selenium and copper deficient grassland moves into the desert steppe in Otog Banner. Only by moderate grazing intensity can forage grasses maintain good quality.

[Objective] To clarify the effect of mowing technique on yield and quality of forage grass in Leymus chinensis mowing meadow in Hulun Buir City, to determine the appropriate mowing period and mowing height （stubble height）, to obtain forage grass with high yield and quality, and to ensure the stable and sustainable utilization of mowing meadow. [Method] The Leymus chinensis mowing meadow in Hulun Buir City was used as experimental object, and three mowing periods and four stubble heights were set up. Field observation and indoor analysis were used to investigate the effect of different mowing techniques on aboveground biomass of vegetation community, nutrient contents of forage grass, and yield of crude protein （CP） per unit area. [Result] The aboveground biomass of vegetation community was affected by rainfall and fluctuated greatly among years, and the forage grass yield was impacted by mowing period and stubble height. The yield of CP per unit area depended on aboveground biomass of vegetation community. The vegetation community diversity index of early mowing was higher, and it increased with the reduction of stubble height. The yield of CP per unit area was higher when the forage grass was mowed around August 15 with stubble height of 5 cm. [Conclusion] The mowing period and stubble height have impact on the yield of forage grass, and the aboveground biomass of vegetation community determines the yield of CP per unit area. The suitable mowing time of Leymus chinensis mowing meadow in Hulun Buir City is around August 15, and the suitable stubble height is about 5 cm. The stubble height should be reduced in drought years.

[Objective] To define the current situation of nutritional components of grassland plant communities in East Ujimqin Banner of Inner Mongolia, to promote the sustainable development of grassland animal husbandry, and to improve the grassland ecological environment. [Method] The grassland plant communities of 10 towns in East Ujimqin Banner had been taken as the research objects in this study. The nutrient contents of the grassland plant communities were analyzed, and the differences and features of nutrient contents among grassland plant communities in different towns were characterized combining with corresponding analysis method. [Result] Minor information was extracted from common factor analysis in Uliyastai Town among the investigated towns, and the information of acid detergent fiber content in nutrients of grassland plant communities extracted from common factor analysis was also limited. The content of neutral detergent fiber was higher than 70% in the grassland plant communities of Samai Town, Gahaile Town and Daotenaoer Town; the content of crude protein was higher than 10% in the grassland plant communities of Ejinaoer Town and Alatanheli Town; the content of crude ash in the grassland plant communities of Huretunaoer Town was 10.53%; the crude protein content of the grassland plant communities in East Ujimqin Banner was decreased from west to east, while the contents of acid detergent fiber and neutral detergent fiber showed an increasing trend. [Conclusion] The variation trend of nutritional components of grassland plant community in East Ujimqin Banner from west to east is revealed by using correspondence analysis method, and the changing law of nutrient contents of the grassland plant communities in towns of East Ujimqin Banner is characterized.

Alxa Bactrian camel is the world′ s major camel species and is a valuable camel germplasm resource. In this paper, the domestication history of Alxa Bactrian camel and the research status of camel milk and meat products were reviewed. Furthermore, the composition and content of amino acids in camel meat were analyzed based on the investigation and determinative data, in hoping to provide help for protection of Alxa Bactrian camel germplasm resources and further development of series products of Bactrian camel.

[Objective] To meet the needs of surgical excision of esophagus, or feeding and sampling of dogs used in physiology experiments, an experimental operation of artificial gastric fistula was performed. [Method] Five middle or large dogs were selected for the operation, and general anesthesia by inhalation was performed after preoperative preparation and examination. The abdominal skins in stomach area were cut, the muscular tissues were separated, the greater curvature of stomach was pulled out, the gastric wall was cut in the area without blood vessels, and the artificial gastric fistula was inserted. A double-layer purse-string suture was performed on the serosal muscular layer of gastric wall. The muscular tissues in abdominal wall were sutured tuberously. Povidone iodine ointment or oil was injected into the gap between muscle and fistula to accelerate granulation formation. After 6 months of operation, granulation tissue samples were taken from 2 dogs for preparing pathological section. [Result] The wounds of all the 5 experimental dogs healed well and could be fed with the fluid diet 15-25 days after operation. The pathological observation showed that granulation tissues grew well and were mature granulation. [Conclusion] This surgical method provides a practical basis for the fistulization of pathological reasons and physiological experiment operation.

Domestic Animal Physiology is a compulsory course for undergraduates majoring in animal science. It is a science to study the normal life activities and corresponding laws of livestock and poultry. With the continuous development and renewal of Internet + education, teaching model and educational concept, the participatory teaching method has gradually become the hot spot of teaching model innovation. The aim of this paper is to explore the application of the participatory teaching model based on Superstar Fanya network teaching platform in teaching of Domestic Animal Physiology, in hoping to lay a theoretical foundation for the teaching reform of this course.

Bioengineering is a major with high practical requirements. Experimental design is one of the compulsory courses for this major, which is very important to cultivate undergraduates′ engineering thinking ability and innovation ability. At present, the Experimental Design of bioengineering major in agricultural colleges and universities is mostly set up independently, and the theoretical knowledges of experimental design are irrelative to the specific experimental courses. It is difficult for undergraduates to apply the principles and methods obtained from this course to the specific experimental process, resulting in the disconnect between theory and experiment. In this study,the experimental design method is integrated into the Bioreaction Engineering Experiment, and the teaching practice is carried out with the example of ′the experiment of producing surfactant by fermentation using Bacillus subtilis′, in hoping to make the undergraduates master the optimizing design method and to improve their engineering design abilities and practical innovation abilities.

The blended teaching model of professional English literature reading, concept diagram and flipped classroom was introduced into the teaching process of Epigenetics for undergraduates majoring in animal science, which improved the undergraduates′ enthusiasm for active learning, cultivated their English reading abilities and summarizing abilities, and achieved good teaching effects. The specific application methods of professional English literature reading, concept diagram and flipped classroom in Epigenetics teaching were summarized, in hoping to improve the teaching effect of Epigenetics and to provide references for the teaching of other biology related courses.