Grain Yield,Biomass Accumulation,and Leaf Photosynthetic Characteristics of Rice under Combined Salinity-Drought Stress

Simultaneous stresses of salinity and drought often coincide during rice-growing seasons in saline lands,primarily due to insufficient water resources and inadequate irrigation facilities.Consequently,combined salinity-drought stress poses a major threat to rice production.In this study,two salinity levels(NS,non-salinity;HS,high salinity)along with three drought treatments(CC,control condition;DJ,drought stress imposed at jointing;DH,drought stress imposed at heading)were performed to investigate their combined influences on leaf photosynthetic characteristics,biomass accumulation,and rice yield formation.Salinity,drought,and their combination led to a shortened growth period from heading to maturity,resulting in a reduced overall growth duration.Grain yield was reduced under both salinity and drought stress,with a more substantial reduction under the combined salinity-drought stress.The combined stress imposed at heading caused greater yield losses in rice compared with the stress imposed at jointing.Additionally,the combined salinity-drought stress induced greater decreases in shoot biomass accumulation from heading to maturity,as well as in shoot biomass and nonstructural carbohydrate(NSC)content in the stem at heading and maturity.However,it increased the harvest index and NSC remobilization reserve.Salinity and drought reduced the leaf area index and SPAD value of flag leaves and weakened the leaf photosynthetic characteristics as indicated by lower photosynthetic rates,transpiration rates,and stomatal conductance.These reductions were more pronounced under the combined stress.Salinity,drought,and especially their combination,decreased the activities of ascorbate peroxidase,catalase,and superoxide dismutase,while increasing the contents of malondialdehyde,hydrogen peroxide,and superoxide radical.Our results indicated a more significant yield loss in rice when subjected to combined salinity-drought stress.The individual and combined stresses of salinity and drought diminished antioxidant enzyme activities,inhibited leaf photosynthetic functions,accelerated leaf senescence,and subsequently lowered assimilate accumulation and grain yield.

Asymmetric expression of CA2 and CA13 linked to calcification in the bilateral mandibular condyles cause crossed beaks in chickens

Crossed beak is a complex mode of inheritance with prevalence ranging from 0.2 to 7.4% in at least 12 chicken strains worldwide.To reveal the intrinsic factors causing crossed beaks,genes expression patterns in bilateral mandibular condyle between affected and normal birds were characterized by RNA sequencing analysis in the present studies.Crossed beak was induced by short length of unilateral mandibular ramus,and a total of 110differentially expressed genes were up-or down-regulated in the affected(short)mandibular condyle side as compared to the normal side.Carbonic anhydrase 2(CA2)and Carbonic anhydrase 13(CA13)were enriched in the carbonate dehydratase activity,and high-expressed in mandibular condyle and osteoblasts(P<0.05).However,both were low-expressed in short mandibular condyle side of affected birds(P<0.05).The carbonate dehydratase inhibitor experiments confirmed that there is positive association between the calcification and carbonic anhydrase isoenzymes.Quantitative analysis with cetylpyridinium chloride showed a decrease in calcification when the cells were transfected with an anti-CA13 shRNA.Our research suggested that CA2 and CA13 are down-calcified in shortside mandibular condyle,and caused mandibular ramus to grow slowly.CA2 and CA13 have the critical role in crossed beaks by regulating calcification of mandibular condyle.

Translocation and Distribution of Carbon-Nitrogen in Relation to Rice Yield and Grain Quality as Affected by High Temperature at Early Panicle Initiation Stage

Due to climate change, extreme heat stress events have become more frequent, adversely affecting rice yield and grain quality. The accumulation and translocation of dry matter and nitrogen substances are essential for rice yield and grain quality. To assess the impact of high temperature stress(HTS) at the early panicle initiation(EPI) stage on the accumulation, transportation, and distribution of dry matter and nitrogen substances in various organs of rice, as well as the resulting effects on rice yield and grain quality, pot experiments were conducted using an indica rice cultivar Yangdao 6(YD6) and a japonica rice cultivar Jinxiangyu 1(JXY1) under both normal temperature(32 ℃/26 ℃) and high temperature(38 ℃/29 ℃) conditions. The results indicated that exposure to HTS at the EPI stage significantly decreased rice yield by reducing spikelet number per panicle, grain-filling rate, and grain weight. However, it improved the nutritional quality of rice grains by increasing protein and amylose contents. The reduction in nitrogen and dry matter accumulation accounted for the changes in spikelet number per panicle, grain-filling rate, and grain size. Under HTS, the decrease in nitrogen accumulation accompanied by the reduction in dry matter may be due to the down-regulation of leaf net photosynthesis and senescence, as evidenced by the decrease in nitrogen content. Furthermore, the decrease in sink size limited the translocation of dry matter and nitrogen substances to grains, which was closely related to the reduction in grain weight and the deterioration of grain quality. These findings significantly contribute to our understanding of the mechanisms of HTS on grain yield and quality formation from the perspective of dry matter and nitrogen accumulation and translocation. Further efforts are needed to improve the adaptability of rice varieties to climate change in the near future.

Decreased panicle N application alleviates the negative effects of shading on rice grain yield and grain quality

Light deficiency is a growing abiotic stress in rice production.However,few studies focus on shading effects on grain yield and quality of rice in East China.It is also essential to investigate proper nitrogen(N)application strategies that can effectively alleviate the negative impacts of light deficiency on grain yield and quality in rice.A two-year field experiment was conducted to explore the effects of shading(non-shading and shading from heading to maturity)and panicle N application(NDP,decreased panicle N rate;NMP,medium panicle N rate;NIP,increased panicle N rate)treatments on rice yield-and quality-related characteristics.Compared with non-shading,shading resulted in a 9.5-14.8%yield loss(P<0.05),mainly due to lower filled-grain percentage and grain weight.NMP and NIP had higher(P<0.05)grain yield than NDP under non-shading,and no significant difference was observed in rice grain yield among NDP,NMP,and NIP under shading.Compared with NMP and NIP,NDP achieved less yield loss under shading because of the increased filled-grain percentage and grain weight.Shading reduced leaf photosynthetic rate after heading,as well as shoot biomass weight at maturity,shoot biomass accumulation from heading to maturity,and nonstructural carbohydrate(NSC)content in the stem at maturity(P<0.05).The harvest index and NSC remobilization reserve of NDP were increased under shading.Shading decreased(P<0.05)percentages of brown rice,milled rice,head rice,and amylose content while increasing(P<0.05)chalky rice percentage,chalky area,chalky degree,and grain protein.NMP demonstrated a better milling quality under non-shading,while NDP demonstrated under shading.NDP exhibited both lower chalky rice percentage,chalky area,and chalky degree under non-shading and shading,compared with NMP and NIP.NDP under shading decreased amylose content and breakdown but increased grain protein content and setback,contributing to similar overall palatability to non-shading.Our results suggested severe grain yield and quality penalty of rice when subjected to shading after heading.NDP improved NSC remobilization,harvest index,and sink-filling efficiency and alleviated yield loss under shading.Besides,NDP would maintain rice’s milling,appearance,and cooking and eating qualities under shading.Proper N management with a decreased panicle N rate could be adopted to mitigate the negative effects of shading on rice grain yield and quality.

Salinity Stress Deteriorates Grain Yield and Increases 2-Acetyl-1-Pyrroline Content in Rice

Salinity stress greatly impacts rice grain yield and quality, as well as the 2-acetyl-1-pyrroline(2-AP) content in grains. The present study was conducted with Nanjing 9108(NJ9108, conventional japonica rice) and Wenliangyou 669(WLY669, indica hybrid rice) in the fields with non-salinity(NS), low salinity(LS), and high salinity(HS) stresses in 2021 and 2022.

Current Status of Conventional and Molecular Interventions for Blast Resistance in Rice

Pyricularia oryzae anamorph of Magnaporthe oryzae is one of the most notorious fungal pathogens causing severe economic loss in rice production worldwide. Various methods, viz. cultural, biological and molecular approaches, are utilized to counteract this pathogen. Moreover, some tolerant or resistant rice varieties have been developed with the help of breeding programmes. Isolation and molecular characterization of different blast resistance genes now open the gate for new possibilities to elucidate the actual allelic variants of these genes via various molecular breeding and transgenic approaches. However, the behavioral pattern of this fungus breakups the resistance barriers in the resistant or tolerant rice varieties. This host-pathogen barrier will be possibly countered in future research by comparative genomics data from available genome sequence data of rice and M. oryzae for durable resistance. Present review emphasized fascinating recent updates, new molecular breeding approaches, transgenic and genomics approaches(i.e. mi RNA and genome editing) for the management of blast disease in rice. The updated information will be helpful for the durable, resistance breeding programme in rice against blast pathogen.

Comparative assessment of physicochemical properties of unripe peach(Prunus persica) and Japanese apricot(Prunus mume)

Objective:To investigate the physicochemical properties of unripe peach-Pruuns persica cv.Mibaekdo(Mibaekdo) and Prunus persica cv.Nagasawa Hakuho(Nagasawa Hakuho) as an alternative to fowl supplement while Japanese apricot(Prunus mume cv.Backaha)(Backaha) was used as a control sample.Methods:The unripe fruits were analyzed for soluble solid(Brix).titratable acidity.pH,total polyphenol content,1,1-diphenyl-2-pierylhydrazyl(DPPH) radical scavenging activity,amygdalin content,free amino acid content,organic acid content,free sugar content,and α-amylase activities.Results:Total polyphenol content of unripe peach ranged between 137.27-151.64 μg/g whereas that of apricot was 160.73 μg/g.DPPH radical scavenging activities of Rackaha was the highest189.16%.) followed by Mibaekdo(85.03%) and Nagasawa Hakuho(41.30%).The highest amount of oxalic acid 1612.8 mg/100 g) was observed in Mibaekdo while that of Nagasawa llakuho and Backaha were(184.6±18.1) and(334.8±16.1) mg/100 g,respectively.Amygdalin contents of Mibaekdo.Nagasawa Hakuho and Backaha were 486.61,548.60 and 174.28 μg/g,respectively.Conclusions:The results suggest that the unripe fruit of peach has a significant biochemical potential of using as a food supplement with potential health benefit for human health.

Application Model of New Agricultural Hotline Sci-tech Information Service System in Beijing

To further promote information construction in rural areas and popularize agricultural information service,we introduced the content of new agricultural hotline sci-tech information service system construction,summed up application effect of the system,analyzed advantages and existing problems in the system development,and put forward countermeasures for its further development.

Effect of Paclobutrazol Application on Plant Growth and Flower Quality in Herbaceous Peony

Herbaceous peony(Paeonia lactiflora Pall.)is an important ornamental plant worldwide.In its natural state,P.lactiflora often manifests traits like rapidly elongating internodal growth,loose plant types,and soft inflorescence stems.However,very little has been known about the measures for controlling these traits.This study investigated the effect of applying paclobutrazol(PBZ)on the plant growth and flower quality in P.lactiflora.The results indicated that PBZ application reduced the plant height(8.05%),plant crown width(14.72%),and leaf area(10.90%),but increased the leaf thickness(18.18%)and stem diameter(over 11%)in P.lactiflora.Meanwhile,PBZ application was also found to increase the chlorophyll(Chl)a(29.63%),Chl b(33.33%),Chl a+b(30.56%),SPAD(27.32%),relative water content(0.47%),soluble sugar(5.09%)and activities of three antioxidant enzymes(superoxide dismutase 169.66%,peroxidase 3.59%,catalase 319.30%),but decreased the relative electrical conductivity(18.52%).Additionally,the application of PBZ was found to affect the flowering quality of P.lactiflora,increasing the flower diameter and fresh weight only in the flower-bud stage.This initiates the bloom stage,where there was a decrease in the total content of the aromatic compounds except for the flower-bud stage,and faded the flower color by reducing the content of anthocyanin.These results demonstrated that the application of PBZ can regulate the P.lactiflora plant types with no significant decrease in its ornamental values.This might provide a theoretical basis for further applying PBZ in P.lactiflora for use in urban landscape spaces.

Genotypic Variation in Spatial Distribution of Fe in Rice Grains in Relation to Phytic Acid Content and Ferritin Gene Expression

Rice varieties having high Fe concentration in the endospermic region can be used as a good source for Fe deficit population.In this study,303 Oryza sativa varieties and 1 Oryza rufipogon accession were assessed for spatial Fe accumulation in grains by Prussian blue staining method.Spatial ferritin protein distribution in grains was visualized by immunohistochemistry,and ferritin expression was assessed in selected rice varieties using semi-quantitative reverse transcription PCR.Three popular rice varieties,namely Sarjoo 52,Madhukar and Jalmagna,and the O.rufipogon variety showed Fe in all the regions of grains,and the highest Fe concentration was observed in the embryo region.Some high-yielding varieties like Swarna,Swarna Sub 1,CSR13 and NDRR359 had lower Fe concentration in the embryo region.The highest Fe concentration was detected in O.rufipogon(49.8μg/g),followed by Sarjoo 52(26.1μg/g)and Madhukar(25.7μg/g).Phytic acid concentration was the minimum in O.rufipogon(5.75 mg/g)followed by Sarjoo 52(5.83 mg/g).Western blot and semi-quantitative reverse transcription PCR showed higher expression of ferritin gene in O.rufipogon,Sarjoo 52 and Madhukar.In conclusion,O.rufipogon and Sarjoo 52 had higher Fe concentration in the embryo regions as well as endosperm and aleurone layer,whereas the other varieties had lower Fe concentration in the endosperm.Sarjoo 52 could be used as a donor in the rice breeding program for the generation of new varieties with elevated grain Fe concentration.

Studies on Agricultural Scientific and Technical Information Core Metadata Register System

To construct the Agricultural Scientific and Technical Information Core Metadata （ASTICM） standard and its expanding principles, and to develop a register system based on ASTICM, the policy and methods of DC （Dublin Core） and SDBCM （Scientific Database Core Metadata） were studied. The construction of ASTICM has started from the proposed elements of the DCMI （Dublin Core Metadata Initiative）, and has expanded the DC and SDBCM with related expanding principles. ASTICM finally includes 75 metadata elements, five expanded principles, and seven application profile creation methods. According to the requirement analysis of a large number of users of agricultural information, a register system based on ASTICM was developed. The ASTICM standard framework and its register system supported the search, sharing, integration exchange and other applications, effectively.

Soil Water Availability on Growth and Development of Safflower Plants

Safflower (Carthamus tinctorius L.) is a promising culture to be widespread in Brazil. However, the lack of basic knowledge about cultivation techniques, such as water demand by the culture, is still obstacle to the expansion of safflower in that country. The objective was, then, to evaluate the effect of the soil water availability on growth and development of safflower in the Cerrado soil of Mato Grosso, Brazil. The experiment was conducted in a greenhouse, in a completely randomized design with five water availabilities (25%, 50%, 75%, 100% and 125% of the maximum water holding capacity in the soil) and four replications. Maintenance soil moisture was performed by gravimetric method with daily weighing of experimental units. The variables analyzed were: plant height, stem diameter, number of leaves, number of heads, heads diameter, dry mass of shoots, heads, and roots. The results were submitted to analysis of variance and regression test at 5% probability by SISVAR program. All variables set to the quadratic regression model, showing the best results in the water availability between 64% and 76%. Safflower is shown to be more sensitive to water stress with increased tolerance to water deficit in the soil than to flooding.

Soil Water Availabilities in the Content and Accumulation of Nitrogen and Chlorophyll Index in the Safflower

The safflower (Carthamus tinctorius L.) is adapted to grow in adverse conditions, is tolerant to salinity and water deficit, however, its productivity increases when grown in areas with greater availability of water and in fertilized conditions, showing that the knowledge of crop management can bring income gains for producers. It is known that extreme conditions of soil moisture damage the crop development. Given this context, the objective was to evaluate the influence of water availability on the nutritional characteristics of the safflower. The experiment was conducted in a greenhouse in a completely randomized design with five water availabilities (25%, 50%, 75%, 100% and 125% of the maximum water holding capacity of the soil) in four replications. Maintaining soil moisture was performed by gravimetric method with daily weighing of experimental units. The variables analyzed were SPAD reading (chlorophyll content), concentration and accumulation of nitrogen in the shoot and in the sections. The results were submitted to analysis of variance and regression test at 5% probability by Sisvar program. There was adjusting of variables to linear and quadratic regression models. Water availabilities between 65% and 75% have greater potential to promote better nutrition for safflower plants. Both deficit and excess of water in the soil are detrimental to the absorption of nitrogen and reduce the chlorophyll content. Safflower is less tolerant to excess than to deficit of water.

Wood Ash Fertilization on Structural Characteristics and Chlorophyll Index of Tropical Forage Grasses

The appropriate nutrient supply via fertilization is essential for an adequate plant growth and development. The objective of this study was to evaluate the structural characteristics and chlorophyll index of Marandu and Xaraes grasses fertilized with wood ash. The experiment was conducted in a greenhouse;the experimental design was entirely randomized, with 12 treatments and six replications arranged in a 2 × 6 factorial scheme: two forage grasses (Marandu and Xaraes) and six wood ash doses (0;3;6;9;12;and 15 g·dm-3). Each plot was composed of pots with 7 dm3 soil and five plants. Soil moisture was maintained by the gravimetric method at 60% of the maximum soil water retention capacity. Three harvests of the plant aerial part were performed at 30-day intervals. The evaluated characteristics were plant height, leaf number, tiller number, and chlorophyll index. Results were submitted to the variance analysis by F test and, after verification of the significant effects on Marandu and Xaraes characteristics, were also submitted to Tukey test;the wood ash doses were evaluated according to the regression analysis at 5% probability. Wood ash doses ranging from 10.15 to 15 g·dm-3 resulted in quadratic responses of plant height, leaf number, and tiller number for both Marandu and Xaraes grasses. The highest values of chlorophyll index derived from wood ash doses of 9.44 and 10.92 g·dm-3, with increments greater than 50%, 25%, and 9% at the first, second, and third harvests, respectively. The wood ash, when used as a fertilizer, improves structural characteristics and increases chlorophyll indices of Marandu and Xaraes grasses cultivated in Cerrado Rhodic Hapludox.

Correction of Acidity of a Brazilian Cerrado Oxisol with Limestone and Wood Ash on the Initial Growth of Cowpea

Among Brazilian soils orders, there are some of it classified as acid soils, which need correction to guarantee crop productivity. Currently, limestone is the most used soil corrective and wood ash has been a sustainable alternative to this process. Thus, the objective was to evaluate the effect of two correctives of soil acidity on an Oxisol collected in the Brazilian Cerrado area using limestone and wood ash and the effect of soil correction on initial growth of cowpea. Two greenhouse experiments were carried out: 1) with limestone, using base saturation levels (V%) of 0, 20, 40, 60 and 80;and 2) wood ash, with doses of 0, 8, 16, 24 and 32 g&#8901;dm&#8722;3, both in five randomized blocks. At 40 days after sowing, it was verified that pH values were within the range considered ideal for soil (pH of 5 to 7), according to the increase of base saturation levels and wood ash doses, but limestone provided faster results. Initial growth of cowpea was positively influenced by soil correction with use of both correctives. Wood ash and limestone increased soil pH to adequate values and resulted in better initial crop development.

Genetic Variation and Correlation Analysis on Seed Oil Content and Protein Content of Brassica campestris L.Germplasm Resources

The content of oil and protein in 84 germplasm materials of Brassica campestris L. from all over the country was tested. In Guiyang environment,the oil content and protein content of these materials showed abundant variation,and were divided into three groups. Correlation analysis showed that there was a significant negative correlation between oil content and protein content of B. campestris L. seeds,and the application and formation mechanism of the negative correlation were also discussed.

Saturation Levels by Bases and Time of Incubation in the Development and Growth of Ornamental Sunflower

Floriculture is a promising segment of Brazilian agriculture. The ornamental sunflower (Helianthus annuus L. cv. Folded Sungold), also known as dwarf sunflower, in addition to being used in gardens can be marketed as cut flower or vase. The sunflower represents a great alternative for small producers because it requires little space, has easy handling and short cycle, besides providing greater economic return. In this context, we aimed to evaluate the development of this culture submitted to different levels of saturation per base, combined with the incubation time of the limestone. The experiment was carried out in a greenhouse at the Federal University of Mato Grosso-University Campus of Rondonópolis. A randomized block design with factorial scheme 6 × 2 was used, with six levels of saturation per base: 0, 20%, 40%, 60%, 80%, 100%;and two incubation times: 0 and 30 days, resulting in 12 treatments with four replicates, totaling 48 experimental units. Each plot consisted of a plastic polyethylene vessel with a capacity of 1.2 dm&#8722;3. The following variables were analyzed: Height of the floral stem;number of leaves, diameter of chapters;root volume;fresh mass of leaves;fresh mass of floral stems;fresh mass of chapters;fresh root mass and chlorophyll index (SPAD). Data were submitted to analysis of variance by the test F at 5% probability of error. The qualitative factors were submitted to the Tukey test and quantitative factors to the regression test, both with a 5% probability of error. Basal saturation levels of 80% and 100%, in the treatment with incubated soil, provided higher quality of inflorescence for commercialization purposes.

Field Identification and Prevention and Control Techniques of Citrus Huanglongbing of Orah Mandarin

In order to promote the development of Orah mandarin industry in Guangxi and reduce the harm of citrus huanglongbing to Orah mandarin,the pathogen,characteristics,occurrence regularity and field symptoms of citrus huanglongbing were summarized,and scientific prevention and control measures were put forward,such as strict implementation of quarantine system,cultivation and use of disease-free seedlings,strengthening field management,timely control of psyllid,timely removal of diseased trees,etc.

Satisfaction of targeted poverty alleviation policies and its influencing factors based on farmers' perspective:Questionnaire survey and research on 1720 farmers in Shaanxi Province of China

Based on the first-hand data of the household survey of targeted poverty alleviation policies,five dimensions were analyzed from the residential regions,the individual characteristics,the household income characteristics,the poverty status and the farmers' relevancy to poverty alleviation policies.Through descriptive statistics and correlation analysis,the satisfaction of targeted poverty alleviation policies and its influencing factors have been inspected.It is found that the farmers,on the whole,are satisfied with the targeted poverty alleviation policies.Their satisfaction for the implementation of local poverty alleviation policies is in a moderate high level,however at the same time they expect the policies to be improved.The impoverished farmers in southern Shaanxi have higher satisfaction towards the poverty alleviation policies.Those farmers' awareness,participation,and benefit are positively related to the level of satisfaction towards policies.The implementation of the poverty alleviation from the government is not only favorable for its people,but also the country.It can greatly enhance the recognition of the government's legitimacy and local government's credibility.To formulate and implement the targeted alleviation policies,the relationship between farmers,especially impoverished farmers,and such policies should be taken into consideration.The starting point and judging criteria of poverty alleviation job should be based on questions whether the farmers know,need,and have the willing to participate in and satisfy with the policies.Those farmers' right to know,participate,benefit and judge should be protected,and it will continuously promote the efficiency of implementing poverty alleviation.

CRISPR/Cas9-mediated knockout of SLC15A4 gene involved in the immune response in bovine rumen epithelial cells

The objective of this study was to determine the role of SLC15A4 in the muramyl dipeptide(MDP)-mediated inflammatory response of bovine rumen epithelial cells(BRECs).First,changes in the m RNA expression of proinflammatory factor genes in BRECs following 10μg m L^(–1)MDP treatments were examined.RT-q PCR results showed that the expression of pro-inflammatory factor(IL-1β,IL-6,and TNF-α)m RNAs were significantly increased under MDP stimulation(P<0.001).Moreover,SLC15A4-Knockout(SLC15A4-KO)cells were obtained through lentivirus packaging,transfection,screening,and cell monoclonal culture.In order to gain further insight into the potential function of SLC15A4,we utilized transcriptome data,which revealed a change in the genes between WT-BRECs and SLC15A4-KO.Five down-regulated pro-inflammatory genes and 13 down-regulated chemokine genes related to the inflammatory response were identified.Meanwhile,the down-regulated genes were mostly enriched in the nuclear factorκB(NF-κB)and mitogen-activated protein kinase(MAPK)signaling pathways.The results of RT-q PCR also verified these detected changes.To further determine the mechanism of how WT and SLC15A4-KO BRECs are involved in inflammatory responses,we investigated the inflammatory responses of cells exposed to MDP.WT-BRECs and SLC15A4-KO were treated with a culture medium containing 10μg m L^(–1)MDP,in comparison to a control without MDP.Our results show that SLC15A4-KO BRECs had reduced the expression of genes(IL-6,TNF-α,CXCL2,CXCL3,CXCL9,and CCL2)and proteins(p-p65 and p-p44/42)from the MDP-mediated inflammatory response compared to WT-BRECs(P<0.05).In this experiment,CRISPR-Cas9 was used to KO the di/tripeptide transporter SLC15A4,and its role was confirmed via the MDP-induced inflammatory response in BRECs.This work will provide a theoretical basis for studying the pro-inflammatory mechanism of MDP and its application in the prevention and treatment of subacute rumen acidosis in dairy cows.