Hybrid data-driven framework for shale gas production performance analysis via game theory, machine learning, and optimization approaches

A comprehensive and precise analysis of shale gas production performance is crucial for evaluating resource potential,designing a field development plan,and making investment decisions.However,quantitative analysis can be challenging because production performance is dominated by the complex interaction among a series of geological and engineering factors.In fact,each factor can be viewed as a player who makes cooperative contributions to the production payoff within the constraints of physical laws and models.Inspired by the idea,we propose a hybrid data-driven analysis framework in this study,where the contributions of dominant factors are quantitatively evaluated,the productions are precisely forecasted,and the development optimization suggestions are comprehensively generated.More specifically,game theory and machine learning models are coupled to determine the dominating geological and engineering factors.The Shapley value with definite physical meaning is employed to quantitatively measure the effects of individual factors.A multi-model-fused stacked model is trained for production forecast,which provides the basis for derivative-free optimization algorithms to optimize the development plan.The complete workflow is validated with actual production data collected from the Fuling shale gas field,Sichuan Basin,China.The validation results show that the proposed procedure can draw rigorous conclusions with quantified evidence and thereby provide specific and reliable suggestions for development plan optimization.Comparing with traditional and experience-based approaches,the hybrid data-driven procedure is advanced in terms of both efficiency and accuracy.

Effects of Low Protein Diets Supplemented with Ami-no Acids on Production Performance,Carcass Qual-ity and Input-output Ratio of Pigs

[Objectives] To study the effects of low-protein diets supplemented with amino acids on the production performance,carcass quality and input-output ratio of fattening pigs and growing-finishing pigs. [Methods] Two studies were conducted on fattening pigs and growing pigs respectively. Pigs in two experimental groupswere fed with low-protein diets supplemented with amino acids and normal diets respectively,and the initial weight,final weight,feed consumption and carcass index of the tested pigs were measured.[Results]The average final weight of fattening pigs in test group was 2. 4 kg lower than that in control group,while the difference was not significant( P > 0. 05). The average daily gain of fattening pigs in test group was 60 g lower than that in control group,indicating that low protein diets had a tendency to decrease the growth rate( P > 0. 05),and reduction of daily weight gain in low protein diet pigs reached 7. 6%. The development of pigs in low protein diet group was poor,however,the difference was not significant. Carcass backfat thickness in low-protein diet group was slightly higher than that in control group,the difference was significant( P < 0. 05). There was no significant difference in input-output ratio between low-protein diet group and control group.Finalweight of growing-finishing pigs in low-protein diet group was 3. 22 % lower than that in control group,the average daily weight gainwas 6. 91% lower than that in control group,feed intake in test group was 5. 48% lower than that in control group,and difference between the two treatments was significant( P < 0. 05). Feed meat ratio in low-protein diet group improved,however,the difference was not significant( P > 0. 05).[Conclusions]Production performance of the pigs would be decreasedand the input-output ratio could not be improvedwhen the adding contents of crude protein in diets was reduced 3%-4%. Therefore,it is recommended that the crude protein level should be enough when pigs were fed with low-protein diets.

Mechanism of the Effect of Bacillus coagulans on Production Performance of Laying Hens in Late Laying Period

[Objective]The paper was to investigate the mechanism of Bacillus coagulans preparation in improving production performance of laying hens in late period of laying.[Method]A total of 648 individuals of"Jingfen 1"laying hens(66 weeks of age)in late period of laying were randomly divided into four groups,six replicates each group,and each group had 27 individuals of laying hens.The laying hens in control group were fed with basal diet,and those in experimental groupsⅠ,Ⅱ and Ⅲ were fed with the basal diets added with 3.33×10^6,1×10^7,3.33×10^7 CFU/g B.coagulans,respectively.The pretrial lasted one week,and the formal test lasted eight weeks.[Result]Compared with the control group,the laying rate in group Ⅰ increased significantly,and the feed-gain ratio in experimental group Ⅱ decreased noticeably while the spleen index increased remarkably;the alkaline phosphatase activities and blood calcium content in experimental groups Ⅰ,Ⅱ and Ⅲ increased significantly(P<0.05),while the triglyceride content decreased remarkably(P<0.05);the urea content in experimental groups Ⅰ and Ⅱ decreased obviously(P<0.05).Adding B.coagulans significantly increased the specific activity of amylase,lipase and protease in various intestinal mucosa of small intestine(P<0.05);adding B.coagulans significantly increased the content of follicle-stimulating hormone(FSH)and estradiol(E2),and significantly increased the mRNA expression of follicle stimulating hormone receptor gene(FSHR).[Conclusion]B.coagulans preparation could significantly improve the production performance of laying hens in late period of laying;appropriately enhance the immune capacity of laying hens;improve the serum biochemical indicators;increase the activity of digestive enzymes in the small intestine;and promote the release of gonadal hormone and the mRNA expression of FSHR gene in the ovary.

Preliminary Study on Production Performance of Different Varieties of Forage Mulberry

A comparative study was conducted on four mulberry( Morus alba) varieties( lines) in Hunan dry land from the aspects of production performance,nutritional composition and amino acids content. The result showed that the four mulberry varieties all adjusted well to soil,climate and other natural conditions in Hunan province,presenting good growth. The dry matter content of four varieties( lines) was above 25% and the crude protein content was more than 22%. Although the crude protein and total amino acid content of four mulberry varieties were lower than that of soybean powder,the proportion of various amino acids tended to be consistent,so mulberry leaf was very comprehensive in nutrition as an animal feed. Yuesang 11 had the highest fresh yield and crude protein of 14. 28 t / hm^2 and23. 22% respectively; Guisangyou 12 had the highest total amino acid content of 19. 58%. There were differences among four varieties,but each variety had its own advantages,so they all had good popularization value.

Typical Correlation Analysis between Forage Type Triticale Production Performance and Different Pilot Ecological Factors

Domestic and foreign researches on triticale mainly focus on hereditary traits and excellent characteristics,but there are few reports on triticale yield and quality in the severe cold pastoral areas of Gansu and Qinghai.In this study,Gannong 2 triticale cultivars have been bred and planted in typical ecological areas according to the characteristics of different ecological regions.By studying the relationship between quality traits and various ecological factors,the effects of different ecological factors on the quality of Triticale hay have been clarified,which provides a reasonable basis for future triticale breeding and large-scale and targeted planting layout.The production performance and nutritional qualities of Triticale Trial in Maqu County,Gansu Province and Gannong No.2 in Dulan County,Qinghai Province are obviously superior to other pilot sites.Through reasonable fertilization,the production performance and nutritional quality of triticale are the best.Triticale production performance is significantly related to climatic factors in different pilots.The most suitable planting area for Gannong 2 is Maqu County,Gansu Province.

Effects of Different Compound Trace Element Premixed Materials on Beef Cattle Production Performance and Anti-oxidation Capacity

In this study,the effects of two types of premixed materials with different combinations of trace elements on the production performance and antioxidant capacity of simmental beef cattle were examined.Fifteen healthy simmental beef cattle of similar weight(approximately 330 kg),the same age(12 months),without castration,and a good physique were divided into three groups,with five beef cattle in each group.Food of Group Ⅰ beef cattle was supplemented with a commercially marketed 5% compound trace element premixture for fine beef cattle.Food of Group Ⅱ beef cattle was supplemented with a 5% compound microelement premixture for beef cattle that was designed to address local nutrient deficiencies and surpluses.In the blank control group,the beef cattle were not fed a premixture.The pretest period was 15 days,and the test period was divided into prefattening(45 days)and postfattening(45 days)stages.Body weight and body size indices were recorded at 1,2 and 3 months,and blood samples were collected regularly.In Group Ⅰ,the daily weight gain increased significantly by 15.7% compared with that of the control group.The largest daily weight gain was in Group Ⅱ,which increased by 31.6% compared with that in the control.During the test period of 90 days,the body size indices of the three different groups increased in different months,with significant increases in the indices for both test groups compared with those of the control.In Group Ⅰ,the activity of CP,the total activity of SOD and Cu-Zn-SOD increased significantly(p<0.05)compared with those in the control group,with a highly significant increase observed in GSH-PX activity(p<0.01).In Group Ⅱ,the increases in the activity of CP and the total activity of SOD and Cu-Zn-SOD were highly significant compared with those in the control group(p<0.01).In addition,a significant increase was observed in GSH-PX activity(p<0.05).Based on pretest results,the concentrations of Cu,Zn,Mo,Mn,Se and Co in the blood of experimental beef cattle were lower than those of the normal range.After feeding for 90 days,the concentrations of Cu,Zn,Mo,Mn,Se and Co in the blood of Groups Ⅰ and Ⅱ were significantly higher than those in the control group(p<0.05).The concentrations of elements in the blood of Group Ⅱ were close to the appropriate levels.Thus,the effects of the specifically designed compound microelement premixture on the prevention of nutrient imbalances and control of beef cattle nutrition metabolism and the production of fattened beef cattle were significant.

Production Performance of Different Varieties of Oat A vena sativa) in Winter Dry Land of Hunan

The phenological phase,plant height,tiller number,nutritional composition,yield and stem/leaf ratio of three oat (Avena sativa) varieties (lines)in winter dry land of Hunan were studied.The result shows that the three oat varieties were greatly different in plant height,nutritional composition,yield and stem/leaf ratio.Baiyan 7 had the best performance,with the plant height,tiller number and fresh yield of 101.67 cm,7.6 tiller/plant and 70.15 t/hm^2 respectively; the crude protein content of dry matter of Baiyan 7 was 32.63%; the leaf weight per tiller of Baiyan 7 accounted for 31.6% of single tiller weight,while those of Baiyan 8 and Baiyan 2 accounted for 31.3% and 29.2%,respectively.The single tiller weight of oat could be estimated/calculated by the model/formula Y=0.043 7X-2.89 (R^2=0.913 4,P<0.01),where Y is the single tiller weight (g) and X is the plant height (cm).Comprehensive analysis showed that Baiyan 7 had higher yields and stem/leaf ratio.Thus,Baiyan 7 is more suitable for planting as a winter-spring forage in the winter dry land of Hunan.

Effects of Different Antibiotics Substitutes on Production Performance of Fattening Pigs

[Objective] The aim was to discuss effects of different antibiotics substitutes on production performance of fattening pigs,and to lay a foundation for development and application of antibiotics-free pig feed.[Method]By adding 100 mg/kg compound probiotics,100 mg/kg compound enzyme preparation,500 and 1 000 mg/kg eu-commin in the basal diet,binary hybrid pigs weighing about 15 kg were reared for 102 d,and the feed added with 300 mg/kg colistin sulfate was used as control.[Result] Using compound probiotics and compound enzyme preparation to substitute antibiotics had no adverse effects on daily weight gain,daily feed intake and feed gain ratio of 15-90 kg fattening pigs; using eu-commin to substitute antibiotics had no adverse effect on daily weight gain,daily feed intake and feed gain ratio of 15-30 kg fattening pigs,but had significant influence on daily weight gain of 30- 90 kg fattening pigs (P<0.05).[Conclusion] It is feasible to develop antibiotics-free pig feed by using new type of green environmental-friendly additive instead of antibiotics.

Effects of Fermented Nano Chinese Herbal Medicines Replacing Antibiotics on Production Performance and Carcass Quality of Growing-Finishing Pigs

[Objectives]To study the effects of fermented nano Chinese herbal medicines replacing antibiotics on the production performance and carcass quality of growing-finishing pigs.[Methods]200 healthy and disease-free Duroc-Landrace-Yorkshire(DLY)growing-finishing pigs with similar birth time(45±2 d)and body weight of about 31.5 kg were randomly divided into group A(fed with non-antibiotic basal diet),group B(fed with antibiotic basal diet),group C(fed with non-antibiotic basal diet+0.1%fermented nano Chinese herbal medicine preparation),group D(fed with non-antibiotic basal diet+0.3%fermented nano Chinese herbal medicine preparation)and group E(fed with non-antibiotic basal diet+0.5%fermented nano Chinese herbal medicine preparation).The experiment lasted for 90 d.At the end of the experiment,the production performance and carcass indicators were measured.[Results]Compared with group A,the final weight,average daily gain(ADG)and average daily feed intake(ADFI)of groups B,C,D and E were extremely significantly increased(P<0.01),while the feed-to-gain ratio(F/G)was extremely significantly decreased(P<0.01).Compared with group B,the ADG of group E was significantly increased(P<0.05),while the F/G was significantly decreased(P<0.05).Compared with group A,the slaughter rate and carcass length of pigs in groups B,C,D and E were extremely significantly increased(P<0.01);compared with group B,the slaughter rate of groups D and E was extremely significantly increased(P<0.01).[Conclusions]The fermented nano Chinese herbal medicine preparation has better effects in promoting growth than that of antibiotic additives,and it can significantly improve the carcass quality of growing-finishing pigs.

Effect of High Concentrate Corn Stalk Particle Size on Physical State and Production Performance of Lactating Dairy Cows

In order to realize the application of corn stalk in cow feed, we designed experiments to explore the effect of a certain proportion of corn stalk on the performance of lactating dairy cows. 9 multiparous mid-lactating cows were allocated at random to three groups, each containing 3 intact cows. The trial consisted of three periods and three dietary treatments with a 3 × 3 Latin square design. The diets were normal concentrats plus dried corn stalk chopped to 5 - 8 cm long (N), high concentrates plus dried corn stalks chopped to a length of approximately 5 - 8 cm by a mower (H) while the milled corn stalks were passed through a pulviser with a 2 cm pore size (MH). Each cow was measured for dry matter intake (DMI), ruminal pH, rumen fermentation, selective feeding behavior and production performance. The results showed that MH led to a significantly higher intake of DM, neutral detergent fiber (NDF), forage NDF (FNDF), acid detergent fiber (ADF), crude protein (CP) and organic matter (OM) than N and H (P < 0.05). Cows fed H and MH showed similar selective feeding behavior, while those fed H showed various selectivity for the dietary component. MH resulted in a significantly higher milk production (P < 0.05), and tended to have a higher milk fat production than N (P = 0.055). There were no significant differences in the milk components (P = 0.424) and lactose (P = 0.113) between cows fed N and MH. The high-concentrates plus milled corn stalk diet can increase the milk yield under the premise of normal rumen pH in dairy cows, thereby generating higher economic benefits. And milled corn stalk can effectively inhibit the cow’s selective eating of low-quality roughage.

Effects of Supplementation with <i>Saccharomyces cerevisiae</i>and Its Fermentation Products on Production Performance and Its Mechanism in Perinatal Dairy Cows

The aim of this study was to investigate the effects of Saccharomyces cerevisiae and its fermentation products on performance, blood hormone levels and rumen floral composition in peripartum dairy cows. Sixty perinatal cows were selected and allocated to two groups according to parity and expected date of delivery. Each group was supplemented with Saccharomyces cerevisiae and its fermentation product 0 or 100 g. The results showed that Saccharomyces cerevisiae and its fermentation products could significantly increase the feed intake of peripartum dairy cows (P < 0.01), increase the lactose content after 21 days postpartum (P < 0.01), and tend to increase milk production (P = 0.052). There was no significant effect on other milk components, the apparent digestibility of nutrients. There was a tendency to increase milk production and reduce the number of somatic cells in milk;increase blood levels of glucagon (P < 0.01) and β-hydroxybutyrate (P = 0.01), reducing the insulin content (P = 0.02). Saccharomyces cerevisiae reduced the abundance of rumen microbes in peripartum dairy cows but had no effect on rumen microbial diversity. Compared with the control group, the supplemented group showed reductions in the abundance of genera Bacillus (P = 0.03), Butyrivibrio (P = 0.01), Denitrobacterium (P = 0.01), and Mogibacterium (P < 0.01), Porphyromonas (P = 0.05), Saccharofermentans (P < 0.01), Sphaerochaeta (P = 0.02), Streptococcus (P = 0.04) and other genera. There were significant increase in the content of Acidaminococcus (P = 0.03), Allisonella (P < 0.01), Bulleidia (P < 0.01), Corynebacterium (P = 0.01), Dialister (P < 0.01), Faecalibacterium (P = 0.02), Faekalitalea (P = 0.03), Fibrobacter (P = 0.04), Flavobacterium (P = 0.03), Kandleria (P < 0.01), Paraprevotella (P < 0.01), Pyramidobacter (P = 0.05), Roseburia (P < 0.01), Succinivibrio (P < 0.01) and other genera. The main metabolic pathways such as tryptophan metabolism and steroid hormone biosynthesis in perinatal dairy cows were determined for Saccharomyces cerevisiae and its fermentation products.

Efficiency Evaluation of Effect of Direct Grain Subsidy Policy on Performance of Rice Production

Using the DEA analysis method,on the basis of the national panel data from 2002 to 2014,this paper made a comparative analysis on the rice production performance before and after the implementation of direct grain subsidy policy,and made an empirical analysis on the relationship between the direct grain subsidy policy and the changes in the rice production performance. The results showed that the effect of the direct grain subsidy policy on promoting the rice production performance is declining year by year,largely because drop of scale efficiency. Besides,there are problems of serious redundancy in agricultural subsidy,unreasonable resource allocation,leading to low performance and resource waste of rice production.

Unevenly distributed LED light produces distinct behavioral preferences and production performance of broilers

LED has shown great advantages in poultry husbandry.This study focused on the behavioral preferences and production performance of chicken broilers reared under unevenly distributed yellow LED light.Four pens were divided into two groups adopting respective maximum light intensities(MLIs,60 lx and 30 lx).Because of different distances from the installation position of the LED pipe,each pen was distributed with unevenly distributed light.Each pen consisted of four subzones indicated by their light intensities-high intensity(HI),medium intensity(MI),low intensity(LI)and weak intensity(WI).Four subzones were the same size and provided with a feeder and a drinker,respectively.The broilers moved freely across the four subzones.No significant differences in body weight(BW),uniformity of final BW and feed conversion ratio(FCR)were observed between the two experimental groups.However,greater feed intake and water intake were found in HI than those in other subzones.The drinking preference changed with age for four subzones and was more likely to appear at the later stage,despite substantial fluctuations within the replicates.The feeding preference was more constant than the drinking preference and appeared mainly at the early and middle stages of this study.These findings could provide implications for broiler production reared under unevenly distributed LED light condition.

Application of Several Additives Instead of Antibiotics in the Production of Laying Hens

[Objective] The test was conducted to study the effect of three different additives instead of antibiotics in the production of laying hens. [Method]Basal diets in four test groups were added with 0. 015% oxytetracycline,0. 01% microecological preparation,0. 2% fulvic acid,and 0. 1% Chinese herbal medicine extract respectively,and laying hens in control group were fed with basal diets. Effect of four different additives on performance and egg quality were studied under the temperature of 28. 6℃. [Result]The average egg-laying rate and feed-egg ratio in groups 2,3 and 4 were significantly better than those in control group and group 1( P < 0. 05). The contents of fat and cholesterol in eggs in groups 2,3 and 4 were lower than those in control group and group 1. And the fat content of eggs in group 4 was 13. 42% lower than that in control group,the difference was significant( P < 0. 05). The protein contents in groups 2,3 and 4 were significantly higher than those in control group and group 1( P < 0. 05). [Conclusion] Microecological preparation,fulvic acid and Chinese herbal medicine extract could replace antibiotics to be applied in the production of laying hens.

An analysis method of injection and production dynamic transient flow in a gas field storage facility

A dynamic transient flow analysis method considering complex factors such as the cyclic injection and production history in a gas field storage facility was established in view of the limitations of the existing methods for transient flow analysis and the characteristics of the injection-production operation of strongly heterogeneous gas reservoirs, and the corresponding theoretical charts were drawn. In addition, an injection-production dynamic transient flow analysis model named "three points and two stages" suitable for an underground gas storage(UGS) well with alternate working conditions was proposed. The "three points" refer to three time points during cyclic injection and production, namely, the starting point of gas injection for UGS construction, the beginning and ending points of the injection-production analysis stage;and the "two stages" refer to historical flow stage and injection-production analysis stage. The study shows that the dimensionless pseudo-pressure and dimensionless pseudo-pressure integral curves of UGS well flex downward in the early stage of the injection and production process, and the dimensionless pseudo-pressure integral derivative curve is convex during the gas production period and concave during the gas injection period, and the curves under different flow histories have atypical features. The new method present in this paper can analyze transient flow of UGS accurately. The application of this method to typical wells in Hutubi gas storage shows that the new method can fit the pressure history accurately, and obtain reliable parameters and results.

Effects of Amino Acid or Fulibao Nutritional Additives on Slaughter Performance and Pork Quality of Pigs

[Objective]The paper was to study the effects of amino acid or Fulibao nutritional additives on slaughter performance and pork quality of pigs,and to provide a theoretical basis for improving pork quality in pig breeding industry.[Method]Six Landrace×Yorkshire castrated male piglets were divided into three groups.The piglets in the first group were fed with conventional diet and used as the control.The piglets in the experimental group I were fed with the conventional diet supplementing 0.1%Fulibao,and those in the experimental group II were fed with the conventional diet supplementing 0.36%compound amino acid preparation.The piglets were reared for 2 months before being slaughtered.[Result]The average daily gains of piglets in the experimental groups I and II were 17.7%and 6.73%higher than that in the control group,but there was no difference in feed/gain ratio among the three groups.The dressing percentages of piglets in the experimental groups I and II were 2.7%and 1.72%higher than that in the control group,and the lean meat percentages were 3.5%and 7.97%higher than that in the control group,respectively.The meat fat ratios in the two experimental groups were significantly higher than that in the control group.The intermuscular fat in the experimental group II was significantly higher than that in the control group.However,the contents of intermuscular fat and inosinic acid in the experimental group II were significantly lower than those in the control group.[Conclusion]Both additives can improve the average daily gain and main slaughter performance of pigs,but can not improve the inosine acid content,and the compound amino acid preparation can not improve the intermuscular fat content.

Total Tract Apparent Digestibility, Serum Fatty Acid Profile, and Productive Performances of Mid-lactating Dairy Cows Fed with Dietary Betaine

It is hypothesized that betaine supplementation improves production performance in mid-lactation dairy cows.Twenty-one mid-lactation dairy cows were assigned to a 3×3 Latin square design with three periods of 28 d each and fed three treatments of betaine(0,100,and 200 g/d).Milk samples were collected on day 21 and day 28 of each period.During days 21 to 28,cows were fed with chromic oxide(15 g/d per cow).On days 26 to 28,fecal samples were collected to determine apparent total tract nutrient digestion.Blood samples were obtained on days 26 to 28 of each period for fatty acid(FA)analysis.Data were analyzed using the Proc Mixed in SAS.Apparent total tract dry matter(DM)digestibility tended to be greater for cows supplemented with 100 g betaine as compared to no dietary betaine(61 vs.58±1%;p=0.1).In contrast,DM intake(DMI),milk fat percent,milk yield,energy-corrected milk(ECM)yield,and milk FA composition did not differ among treatments.Supplementation of betaine can decrease the serum saturated FA C11,C12,C15 and C17,total monounsaturated FA,and C18:2 all trans-9,12.In addition,total serum n-3 polyunsaturated FA was significantly increased.This result can decrease total serum n-6 to n-3 ratio(6.80,7.07,and 6.50±0.16%,for 0,100,and 200 g betaine,respectively;p=0.04).Overall,even betaine supplementation did not change DMI or production,betaine could affect the DM digestibility and serum FA biosynthesis.

Utilizing Dynamic Data to Quickly Evaluate Advantageous Channels and Applications

In response to the high cost and difficulty of high-speed development and testing data in offshore oil fields, this paper proposes to use the most easily available production performance data as the basis and use the grey correlation method to calculate the correlation coefficient between oil and water wells to characterize the degree of development of advantageous channels. The consistency between the calculated results of this method and the tracer test results is over 80%. Based on the fitting results, the correlation coefficient exceeds 0.74 to determine the existence of an advantageous channel. According to the research results of grey correlation method, Bohai K oilfield has completed the combined profile control and flooding measures, and the daily oil production has increased by 20 m3/d. This method is simple, fast, and can achieve quantitative evaluation, which saves time and investment compared to offshore testing. It has strong application and reference value for the development of other offshore water injection oilfields.

Phenolic compounds as natural feed additives in poultry and swine diets:a review

Due to ban on using antibiotics in feed industry,awareness of using natural feed additives have led to a great demand.The interest of plants phenolic compounds as a potential natural antioxidant source has been considered in research community due to their predictable potential role as feed additives in poultry and swine production.However,the mode of action for their functional role and dosage recommendation in animal diets are still remain indistinct.Taking into account,the present review study highlights an outline about the mode of action of phenolic compound and their experimental uses in poultry and swine focusing on the growth performance,antioxidant function,immune function,antimicrobial role and overall health status,justified with the past findings till to date.Finally,the present review study concluded that supplementation of phenolic compounds as natural feed additives may have a role on the antioxidant,immunity,antimicrobial and overall production performance in poultry and swine.

Characterization and mitigation option of greenhouse gas emissions from lactating Holstein dairy cows in East China

Background:This study investigated greenhouse gas(GHG)emission characteristics of lactating Holstein dairy cows in East China and provided a basis for formulating GHG emission reduction measures.GreenFeed system was used to measure the amount of methane(CH_(4))and carbon dioxide(CO_(2))emitted by the cows through respiration.Data from a commercial cow farm were used to observe the effects of parity,body weight,milk yield,and milk component yield on CH_(4) and CO_(2) emissions.Results:Mean herd responses throughout the study were as follows:111 cows completed all experimental processes,while 42 cows were rejected because they were sick or had not visited the GreenFeed system 20 times.On average,lactating days of cows was 138±19.04 d,metabolic weight was 136.5±9.5 kg,parity was 2.8±1.0,dry matter intake(DMI)was 23.1±2.6 kg/d,and milk yield was 38.1±6.9 kg/d.The GreenFeed system revealed that CH_(4) production(expressed in CO_(2) equivalent,CO_(2)-eq)was found to be 8304 g/d,CH_(4)_(CO_(2)−eq)/DMI was 359 g/kg,CH_(4)_(CO_(2)−eq)/energy-corrected milk(ECM)was 229.5 g/kg,total CO_(2) production(CH_(4) production plus CO_(2) production)was 19,201 g/d,total CO_(2)/DMI was 831 g/kg,and total CO_(2)/ECM was 531 g/kg.The parity and metabolic weight of cows had no significant effect on total CO_(2) emissions(P>0.05).Cows with high milk yield,milk fat yield,milk protein yield,and total milk solids yield produced more total CO_(2)(P<0.05),but their total CO_(2) production per kg of ECM was low(P<0.05).The total CO_(2)/ECM of the medium and high milk yield groups was 17%and 27%lower than that of the low milk yield group,respectively.Conclusions:The parity and body condition had no effect on total CO_(2) emissions,while the total CO_(2)/ECM was negatively correlated with milk yield,milk fat yield,milk protein yield,and total milk solids yield in lactating Holstein dairy cows.Measurement of total CO_(2) emissions of dairy cows in the Chinese production system will help establish regional or national GHG inventories and develop mitigation approaches to dairy production regimes.