Impact on Soil Organic C and Total Soil N from Cool- and Warm-Season Legumes Used in a Green Manure-Forage Cropping System

Annual forage legumes are important components of livestock production systems in East Texas and the southeastern US. Forage legumes contribute nitrogen (N) to cropping systems through biological N fixation, and their seasonal biomass production can be managed to complement forage grasses. Our research objectives were to evaluate both warm- and cool-season annual forage legumes as green manure for biomass, N content, ability to enhance soil organic carbon (SOC) and soil N, and impact on post season forage grass crops. Nine warm-season forage legumes (WSL) were spring planted and incorporated as green manure in the fall. Forage rye (Secale cereale L.) was planted following the incorporation of WSL treatments. Eight cool-season forage legumes (CSL) were fall planted in previously fallow plots and incorporated as green manure in late spring. Sorghum-sudangrass (Sorghum bicolor x Sorghum bicolor var. sudanense) was planted over all treatments in early summer after forage rye harvest and incorporation of CSL treatments. Sorghum-sudangrass was harvested in June, August and September, and treatments were evaluated for dry matter and N concentration. Soil cores were taken from each plot, split into depths of 0 to 15, 15 to 30 and 30 to 60 cm, and soil C and N were measured using combustion analysis. Nylon mesh bags containing plant samples were buried at 15 cm and used to evaluate decomposition rate of above ground legume biomass, including change in C and N concentrations. Mungbean (Vigna radiata L. [Wilczek]) had the highest shoot biomass yield (6.24 t DM ha-1) and contributed the most total N (167 kg∙ha-1) and total C (3043 kg∙ha-1) of the WSL tested. Decomposition rate of WSL biomass was rapid in the first 10 weeks and very slow afterward. Winter pea (Pisum sativum L. spp. sativum), arrow leaf clover (Trifolium vesiculosum Savi.), and crimson clover (Trifolium incarnatum L.) were the most productive CSL in this trial. Austrian winter pea produced 8.41 t DM ha-1 with a total N yield of 319 kg N ha-1 and total C production of 3835 kg C ha-1. The WSL treatments had only small effects on rye forage yield and N concentration, possibly due to mineralization of N from a large SOC pool already in place. The CSL treatments also had only minimal effects on sorghum-sudangrass forage production. Winter pea, arrow leaf and crimson clover were productive cool season legumes and could be useful as green manure crops. Mungbean and cowpea (Vigna unguiculata [L.] Walp.) were highly productive warm season legumes but may include more production risk in green manure systems due to soil moisture competition.

The age at first consumption of forage in calves and its effect on growth and rumination in the short‑and long‑term

Background Previous investigations into the effect of dietary forage on calf performance have been inconsistent,and there is a paucity of information exploring the effect of age on the growth performance and rumination of calves.Eighty-four female Holstein calves(41.5±4.2 kg)were enrolled at birth,a subset of the calves were fed calf starter only(CON,n=21)while the rest(n=63)were classified into three treatment groups:the early(EHAY,n=26,5.1±0.8 d),the middle(MHAY,n=21,7.9±0.8 d)and the late(LHAY,n=16,12.1±1.4 d)hay consumers.The short-term effect of the age at first forage consump-tion(AFF)on calves’feed intake was monitored until d 84.In addition,the long-term effects of AFF on body weight,structural growth and rumination behavior were recorded until d 196.Rumen samples were collected on d 1,7,35,84 and 196 to ana-lyze the rumen fermentation,while fecal samples were collected from d 78 to 84 to estimate digestibility parameters.Results Treatment had no effect on feed intake.While,the EHAY calves tended to have lower BW and ADG compared to LHAY and CON calves.Several total-tract apparent digestibility parameters and digestible nutrients intake were significantly lower in EHAY calves compared with CON and LHAY calves.Calves in the EHAY group tended to begin ruminating ealier,while CON calves were the latest(12.3 vs.15.5 days of age).A treatment and time interaction was present for rumination time due to greater rumination in calves consuming hay compared to CON calves in week 10 to 12,the differences in rumination disappeared afterwards,no long-lasting significant differences in the rumina-tion and rumen fermentation parameters were found between treatments.Conclusions In conclusion,this study showed that hay consumption earlier in life(in the first week,around 5 days of life)could negatively affect the growth of the calf in the short and long term.Compared to consuming hay from the second week(around 12 days of life)or feeding concentrate only without hay,starting to consume hay from the first week could compromise nutrient digestibility and digestible nutrient intake independent of developing rumination behaviour and rumen fermentation.

The type of lipid supplement has crucial implications for forage particle size in calf starter diets

Background Forage inclusion in starters of young dairy calves has become an acceptable strategy in the last decade.To compensate for the lower energy provided by forage,concurrent lipid supplementation can be proposed.How-ever,ruminal microbial activity and forage digestibility may be decreased by lipid supplementation.We hypothesized that the composite effect of forage and lipid supplements may be dependent on forage particle size and the type of lipid supplement.Therefore,we evaluated the effect of long(LP;geometric mean,4.97 mm)vs.short alfalfa hay particle sizes(SP;geometric mean,1.26 mm)with either soybean oil(SBO)or palm fatty acids(PLF)as lipid source in a 2×2 factorial design with treatments SP-SBO,SP-PLF,LP-SBO,and LP-PLF.Treatments(n=13 with 6 males and 7 females each)were offered to Holstein calves(3 days old)with equal amounts of lipid(25 g/kg DM)through-out the experimental period.The milk offering scheme(d 1 to 53)was equal for all groups.Data collection continued until 20 d post-weaning.Results Interaction between forage particle size and lipid supplement was significant for the following readouts:the highest and lowest starter intakes during the pre-weaning period occurred in LP-PLF and LP-SBO,respectively.This was associated with similarly contrasting changes in average daily gain(ADG)during the post-weaning period,body weight at the end of experiment,withers height,digestibility of organic matter and neutral detergent fiber,and blood serum concentrations of glucose,beta-hydroxybutyrate,and insulin during the pre-weaning period.Dur-ing both pre-and post-weaning periods,the highest and lowest urinary excretion of allantoin and total purine deriva-tives,representing microbial protein synthesis,were observed in LP-PLF and LP-SBO,respectively,indicating that those diets were most and least favorable for rumen development.Irrespective of forage particle size,supplemental SBO vs.PLF increased serum malondialdehyde as an oxidative stress indicator across periods,increased blood urea nitrogen and feed efficiency in the pre-weaning period,and reduced hip height during the post-weaning period.Conclusions It can be concluded that feeding a rumen-inert,mostly saturated fatty acid source with alfalfa hay as long particle size is recommended with view on performance,whereas a combination soybean oil rich in unsatu-rated fatty acids should not be provided to milk-fed Holstein calves together with long particle forage.Feeding soybean oil and alfalfa hay as long particles is not advisable mainly due to lower starter consumption and impaired development of ruminal function.If dietary supplementation of soybean oil is applied,incorporation of forage as small particles should be preferred to support rumen development.

Effects of Stylosanthes scabra Forage Supplementation on in Vitro Gas Production and Fiber Degradation of Eragrostis Grass Hay

Natural pastures constitute a major component of ruminant livestock feed, and are the most cost-effective feed resource available for smallholder subsistence farmers. However, this feed resource does not meet animal nutritional requirement due to deficiency in nitrogen, energy and minerals. In addition, at maturity lignification is the major concern since it reduces digestibility and contributes to methane emission. Thus, the objective of this study was to evaluate the effect of supplementing low-quality Eragrostis grass hay with five (9281, 11,252, 11,255, 11,595 and 11,604) selected Stylosanthes scabra accessions on in vitro ruminal fermentation and neutral detergent fiber degradation. Therefore, in vitro study was conducted on grass hay, accessions and the mixture of grass hay with each accession included at two (15%, 30%) levels. The substrates (grass hay, accessions and the mixtures) were incubated in separate serum bottles for 72 h. Neutral detergent fiber (NDF) of the accessions ranged from 300 to 350 g/kg DM with crude protein (CP) value ranging from 177.5 to 184.1 g/kg DM. Eragrostis grass hay had NDF value of 813 g/kg DM, with CP value of 34.3 g/kg DM. Grass hay fermented slowly, it took 30 h for grass hay to produce gas volume above 50 mL, while Stylosanthes scabra accessions took 12 h. Supplementing grass hay with accessions significantly improved fermentation. However, it was observed that 15% inclusion took 30 h to produce gas volume above 50 mL, whereas at 30% inclusions it took 24 h for accession 9281, 11,595 and 11,604. Accession 11,604 improve grass fermentation by almost three times the value of grass hay in 2 h. Grass hay supplemented with accession 11,604 at 30% had a positive associative effect and significantly improved NDF degradability. In conclusion, accession 11,604 may be fed strategically as forage supplement to low-quality forage for ruminants.

Effects of Meteorological Factors on Overwintering Ability,Yield and Quality of Forage Rape

In order to investigate the effects of meteorological factors on rape overwintering ability,forage yield and quality of rape in the North China plain,Brassia campestris L.and Brassica napus L.were used in this study.The results showed that compared with the B.napus L.varieties,the growth period of B.campestris L.was shortened by 10-15 d,the overwintering rate(WR)increased by 50.6%,and the density after winter(PD)increased by 41.5%.The fresh forage yield(FFY)and dry forage yield(DFY)of the B.campestris L.type significantly increased by 40.9%and 38.1%compared with the B.napus L.type.,respectively,while the forage quality of the B.napus L.type rape was significantly better than that of the B.campestris L.type.Compared with the B.campestris L.type,the crude protein(CP),fat,ash and total fatty acid(TFA)contents of the B.napus L.type of rape increased by 27.6%,42.9%,23.9%and 52.3%,respectively,and the milk productivity(HM),relative forage value(RFV)and relative forage quality(RFQ)increased by 14.0%,16.2%and 42.1%,respectively.The light and heat resources before wintering increased the WR and PD(P<0.05),and were positively correlated with FFY and DFY(P>0.05),and lower temperature during the wintering period led to lower WR(P<0.01).The light and heat resources during the overwintering period and after regreening were negatively correlated with FFY and DFY(P>0.05).The contents of CP,fat and TFA of rape had an extremely significant negative correlation with the temperature and sunshine hours before wintering,but an extremely significant positive correlation with the temperature during the wintering period and after regreening,as well as the sunshine hours and rainfall during the wintering period;and HM had an extremely significant positive correlation with the temperature,sunshine hours and rainfall during the wintering period,while RFV and RFQ were only extremely significantly positively correlated with the maximum temperature and rainfall.In summary,in the North China Plain,for autumn sowing rape,the B.campestris L.type can be selected to improve the wintering rate,and the B.napus L.type should be the main choice to improve the forage quality of rape.Therefore,the B.napus L.variety HYZ62 can be selected for autumn sowing in the North China Plain.

Spatiotemporal patterns of the forage-livestock balance in the Xilin Gol steppe,China:implications for sustainably utilizing grassland-ecosystem services

Understanding the spatiotemporal patterns of the forage-livestock balance is imperative for regionally arranging animal husbandry production while ensuring sustainable grassland-ecosystem service use.The Xilin Gol steppe is an important native grassland resource in Inner Mongolia Autonomous Region,China.This study aimed to elucidate the dynamics of the forage-livestock balance in the Xilin Gol steppe during the period 2000–2015.We evaluated the forage production and corresponding livestock carrying capacity(LCC)in the growing seasons of 2000–2015 using remote sensing data and field surveys.The spatiotemporal patterns of the forage-livestock balance were then assessed at regional,city(including city,county and banner),and village scales using statistical and household survey data.The results showed that both forage production and LCC decreased in the Xilin Gol steppe from east to west.During the period 2000–2015,the regional average forage production and corresponding LCC fluctuated without following a distinct trend,but were consistent with the variations in precipitation.The forage-livestock balance varied with time,space,and scale.At the regional scale,steppes were overgrazed in the early 2000s,but a forage-livestock balance or even grazing potential was achieved in other years.At the city scale,approximately half of the region exhibited a"forage-livestock balance"since 2000.However,about half of the region still experienced overgrazing,which mainly located in the southwest sandy zones.Such changes may have been affected by the variations in grassland quality,forage production,compensation payment,and so on.We suggest a location-specific management scheme for grazing constraints,ecological compensation payment,and industry development to aid in harmonizing animal husbandry and environmental restoration,while promoting sustainable development goals by 2030.

Chemical composition and in vitro fermentation characteristics of high sugar forage sorghum as an alternative to forage maize for silage making in Tarim Basin, China

The chemical composition, mineral profile and in vitro fermentation characteristics of maize （MZ）, high sugar forage sorghum （HS） and forage sorghum （FS）, and silages made from each forage type were measured. The MZ and MZ silage （MZS） had higher crude protein, starch and ether extract contents than both sorghum forages and sorghum silages. HS had higher ash and water-soluble carbohydrate concentrations than FS and MZ. MZ, MZS, HS and HS silage （HSS） had lower neutral detergent fibre, acid detergent fibre and acid detergent lignin than FS and FS silage （FSS）. FSS had higher dry matter （DM） and pH than MZS and HSS. HSS contained higher concentrations of P and K than FSS and MZS. MZS and HSS had higher in vitro dry matter and organic matter digestibility, CH4 production, total volatile fatty acids, acetate and propionate than FSS. pH was higher for FSS than for HSS, and ammonia was lower for HSS than for MZS and FSS. HSS had higher gas production than MZS and FSS after 2, 4, 6 and 8 h incubation. MZS had higher gas production than HSS and FSS after 26 and 28 h of incubation. The results indicate that HS may substitute for MZ to make good quality silage. However, animal studies are needed to assess the acceptability and feeding values of HSS vs. MZS for ruminant production.

The genome of Medicago polymorpha provides insights into its edibility and nutritional value as a vegetable and forage legume

Medicago polymorpha is a nutritious and palatable forage and vegetable plant that also fixes nitrogen.Here,we reveal the chromosome-scale genome sequence of M.polymorpha using an integrated approach including Illumina,PacBio and Hi-C technologies.We combined PacBio full-length RNA-seq,metabolomic analysis,structural anatomy analysis and related physiological indexes to elucidate the important agronomic traits of M.polymorpha for forage and vegetable usage.The assembled M.polymorpha genome consisted of 457.53Mb with a long scaffold N50 of 57.72Mb,and 92.92%(441.83Mb)of the assembly was assigned to seven pseudochromosomes.Comparative genomic analysis revealed that expansion and contraction of the photosynthesis and lignin biosynthetic gene families,respectively,led to enhancement of nutritious compounds and reduced lignin biosynthesis in M.polymorpha.In addition,we found that several positively selected nitrogen metabolism-related genes were responsible for crude protein biosynthesis.Notably,the metabolomic results revealed that a large number of flavonoids,vitamins,alkaloids,and terpenoids were enriched in M.polymorpha.These results imply that the decreased lignin content but relatively high nutrient content of M.polymorpha enhance its edibility and nutritional value as a forage and vegetable.Our genomic data provide a genetic basis that will accelerate functional genomic and breeding research on M.polymorpha as well as other Medicago and legume plants.

An ethnobotanical study of forage plants in Zhuxi County in the Qinba mountainous area of central China

In the Qinba mountainous area of Central China,pig farming has a significant impact on the growth of the rural economy and has substantially increased farmer incomes.Traditional knowledge plays an important role in the selection of forage plant species for pig farming by local people.This study aimed to identify the forage plants used for pig feeding and to catalog indigenous knowledge regarding their use.During 2016 and 2017,ethnobotanical surveys and inventories were conducted in Zhuxi County,Hubei Province,China.Data were collected using semi-structured interviews,key informant reports,free listings,guided field walks,and participatory observations with 77 households in 16 villages in 13 towns/townships.The obtained data were analyzed using a relative frequency citation(RFC)index.Overall,145 wild forage plants from 91 genera and 31 families were recorded.The most cited families were Asteraceae,Polygonaceae,Urticaceae,Amaranthaceae,Fabaceae,Cruciferae,Caryophyllaceae,and Lamiaceae.Whole plants(75.9%)and tender leaves(12.4%)were the most frequently used parts of the plants.Most of the forage plants were herbaceous(88.9%).Almost all forage plants could be collected throughout the year(62.7%).Raw and cooked were the two main preparation methods.The most frequently cited species were Taraxacum mongolicum,Bidens pilosa,Sonchus oleraceus,Pilea verrucosa,and Pilea pumila var.obtusifolia.A total of 14 species were identified as the top forage plants in Zhuxi County based on their RFC values(RFC value greater than 0.5).Local people possess rich traditional knowledge about the utilization and management of forage plants for pig feeding.However,the maintenance of this traditional knowledge may be seriously threatened by changes in pig feeding modes and the lack of successors.Appropriate strategies and action plans have been suggested for the conservation of traditional knowledge associated with biodiversity and the sustainable use of forage species resources.These include 1)taking targeted measures to protect forage resources and associated traditional knowledge;2)strengthening research on the forage plants with the highest RFC values for nutritional value,digestibility,other functions,and ecological status;and 3)enhancing the identification of poisonous forage plants.

Accuracy comparison of dry matter intake prediction models evaluated by a feeding trial of lactating dairy cows fed two total mixed rations with different forage source

Dry matter intake （DMI） prediction models of NRC （2001）, Fox et aL （2004） and Fuentes-Pila et aL （2003） were targeted in the present study, and the objective was to evaluate their prediction accuracy with feeding trial data of 32 lactating Holstein cows fed two total mixed rations with different forage source. Thirty-two cows were randomly assigned to one of two total mixed ration groups： a ration containing a mixed forage （MF） of 3.7% Chinese wildrye, 28.4% alfalfa hay and 26.5% corn silage diet and another ration containing 33.8% corn stover （CS） as unique forage source. The actual DMI was greater in MF group than in CS group （P=0.064）. The NRC model to predict DMI resulted in the lowest root mean square prediction error for both MF and CS groups （1.09 kg d-1 vs. 1.28 kg d-1） and the highest accuracy and precision based on concordance correlation coefficient for both MF and CS diet （0.89 vs. 0.87）. Except the NRC model, the other two models presented mean and linear biases in both MF and CS diets when prediction residuals were plotted against predicted DMI values （P〈0.001）. The DMI variation in MF was caused by week of lactation （55.6%）, milk yield （13.9%）, milk fat percentage （7.1%） and dietary neutral detergent fiber （13.3%）, while the variation in CS was caused by week of lactation （50.9%）, live body weight （28.2%）, milk yield （8.4%）, milk fat percentage （5.2%） and dietary neutral detergent fibre （3.8%）. In a brief, the NRC model to predict DMI is comparatively acceptable for lactating dairy cows fed two total mixed rations with different forage source.

Effects of Plant Density on Forage Nutritive Value of Whole Plant Corn

In the field experiment, the effects of plant densities (75 000, 112 500 and 150 000 plants ha-1) on forage nutritive value of whole plant corn (WPC) were studied from 1999 to 2001. The results demonstrated that with the increasing of plant density, the forage matter yield per plant corn decreased significantly, while the fresh matter and dry matter per hectare corn increased significantly, and a higher grains yield was gotten at higher plant densities. Forage nutritive quality of whole plant corn was changed as plant density increased, the crude protein (CP), ether extract (EE), crude fiber (CF), nitrogen free extract (NFE) and general energy (GE) yields increased obviously. Increas- ing plant density reasonably with the application of plant growth regulators could improve plant properties, harvest more forage matter, and enhance forage nutritive value of WPC.

Diversity shifts of rumen bacteria induced by dietary forages in dairy cows and quantification of the changed bacteria using a new primer design strategy

The partial 16 S r RNA gene sequences（100 to 500 bp） were widely used to reveal rumen bacterial composition influenced by diets, while quantification of the changed uncultured bacteria was inconvenient due to difficult designing of specific primers based on short sequences. This study evaluated the effect of forage resources on rumen bacterial diversity and developed new strategy for primer design based on short sequences to quantify the changed uncultured bacteria. Denaturing gradient gel electrophoresis（DGGE） analysis and subsequent band sequencing were used to reveal the distinct rumen bacteria composition in cows fed with two forage sources（single corn stover vs. mixed forages including alfalfa hay and corn silage）. The bacterial diversity in the rumen of dairy cows fed with corn stover was lower than that with mixed forages（P0.05）. The bacterium named R-UB affiliating to uncultured Succinivibrionaceae was identified, and it was abundant in the rumen of cows fed with mixed forages compared to corn stover. The full length 16 S r RNA gene sequences with identity of 97% to the R-UB 16 S r RNA gene sequence were obtained from Gen Bank and used to design specific primers to quantify uncultured bacterium R-UB. All sequences of amplicon from the new primers were of 100% identity to R-UB sequences indicating the high specificity of new primers. Quantitative PCR confirmed that abundance of R-UB in the rumen of cows fed with corn stover was lower than those fed with mixed forages（P0.01）. New strategy for designing primers based on partial 16 S r RNA genes to quantify targeted uncultured bacteria was successfully developed. The rumen bacteria descending significantly in the cows fed corn stover compared to those fed mixed forages was identified as uncultured R-UB from Succinivibrionaceae.

Isolation and Identification of High-Quality Lactic Acid Bacteria in Forage Corn

[ Objective] To screen suitable lactic acid bacterium strains from forage corn which can be used as silage additives. [ Method] The lactic acid bacterium strains were isolated by inoculation on MRS solid medium containing calcium carbonate, and they were preliminarily identified through morphological, physiological and biochemical experiments. The acid production efficiency was determined. Twelve strains having strong acid-pro- duction ability were selected, and their salt tolerance and acid tolerance were detected. The sequences of their 16 S rDNA were also analyzed. [ Result] A total of 44 lactic acid bacterium strains were isolated from the forage com. As evidenced by the physiological and biochemical experi- ments, the twelve strains having strong acid-production ability belonged to Leuconostoc, Lactobacillus and Enterococcus, respectively, and they had strong salt tolerance and acid tolerance. According to the sequences of 16 S rDNA, A4, B9, B11, B12 and B14 were Lactobacillus plantarum; A1, A2., A7, A11 and B8 were Leuconostoc mesenteroides dextran subspecies; and AB and A9 were Enterococcus hirae. [ Conclusion ] The lactic acid bacterium strains with strong acid-production ability isolated from forage corn can be developed into silage additives.

The control of soil polarization in Populus simonii and Quercus liaotungensis forests by forage litter on the Loess Plateau,P. R. China

Soil polarization in pure forest stands affects the stability and sustainable development of the ecosystem. The most effective approaches to the prevention of soil polarization may be the use of forage litter as fertilizer or the direct establishment of tree-grass communities. We investigated monospecific plantations of Populus simonii and Quercus liaotungensis. Such plantations have been established throughout the Loess Plateau of China. A 120-day decomposition incubation experiment with forest humus soil mixed with 7 common leguminous forage litterspecies was performed to study the uses of forage litter in controlling soil polarization in pure forests. The addition of forage litter of Astragalus adsurgens, Lespedeza bicolor, and Vicia viUosa to the soil of pure P. simonii forest clearly improved the soil quality, these forage species are suitable for planting with P. simonii, whereas Melilotus officinalis, Medicago sativa, and Onobrychis viciifolia litter produced obvious deterioration, thus these forages should not be planted with P. simonii. Coronilla varia litter showed no significant influence. The addition of forage litter of M. sativa to the soil of pure Q. liaotungensis forest clearly improved the soil quality, and C. varia and V. villosa also yielded improvements but were slightly less effective than M. sativa litter, these forages are suitable to be planted with Q. liaotungensis. However, L. bicolor showed obvious deterioration, followed by O. viciifolia and A. adsurgens, and M. officinalis had no significant influence. These spe- cies should not be planted with Q. liaotungensis.

Ethnobotanical study of forage/fodder plant species in and around the semi-arid Awash National Park, Ethiopia

We undertook ethnobotanical study of forage/fodder plant species used by the Afar and Oromo （Kereyu and lttu） Nations in and around the semi=arid Awash National Park （ANP）, Ethiopia. The study aimed at investigating and documenting indigenous knowledge （IK） on forage/fodder plant species and threats to their survival. Ninety-six in= formants between 20 and 80 years old were selected using prior informa- tion. Data were collected using semi-structured interview, guided field wail discussion and field observation. Preference ranking, Jaccard＇s coefficient of similarity and priority ranking were used for data analysis. One hundred twenty-six forage/fodder species of 90 genera and 43 fami- lies were collected in the study area. More than 88% of the species were reported with their vernacular names, where 68% were reported by the Afar Nation and 70% by the Oromo Nation. Family Poaceae was repre- sented by 25 species （20%）, followed by Fabaceae 18 （14%）. Preference ranking for the most preferred forage grasses as perceived by key informants revealed that Chrysopogon plumulosus was the most important forage/fodder species. Overgrazing was the major threat in the study area, scoring 22%.

Effects of Different Nitrogen Application Strategies on Yield and Forage Nutritive Quality of Zea mexicana

A pool experiment was carried out to study the effects of different nitrogen applicationstrategies (rates and stages of nitrogen application) on yield and forage nutritivequality of Zea mexicana cultivated in summer, 2002. In the whole growing stage, its stemwas clipped three times at the height of 25cm when it was 110cm high (H1, H2 and H3 standfor the first, second and third harvest stage, respectively). Six indexes includingcrude protein (CP), ether extract (EE), nitrogen free extract (NFE), acid detergentfiber (ADF), crude ash (CA), and general energy (GE) were employed to evaluate the foragenutritive value. The results showed that the content of CP and EE increased but thecontent of CA and ADF decreased under the two nitrogen rates (High-rate N, 600kgha-1;Mid-rate N, 300kgha-1). The fresh and dry harvest biomass of the whole plants on H1 andthose of the leaves on H2 were also improved. But the stalks on H2 and the whole plantson H3 were affected mainly by dressing nitrogen fertilizer. The yield of CP and EE, CA,NFE, and GE was mainly affected by nitrogen rates. The ADF yield increased was due to theincrement of the fresh and dry harvest biomass. Nitrogen applied as base fertilizer forsummer Zea mexicana can be harvested a higher biomass and improve the forage nutritivequality.

Yield and Quality of Forage Oat (<i>Avena sativa</i>L.) Cultivars as Affected by Seed Inoculation with Nitrogenous Strains

Nitrogen availability can be enhanced with the application of nitrogen fixing bacteria and it may be helpful in increasing forage yield and improving quality of oat. Therefore, a field trial to evaluate the effect of seed inoculation with nitrogen fixing bacteria on forage yield and quality of oat was carried out at Agronomic Research Area, University of Agriculture, Faisalabad during Rabi season 2013-14. The experiment was laid out in Randomized Complete Block Design (RCBD) with factorial arrangements using three replications. The experiment was comprised of two integrated approaches. The first approach was oat cultivars consisting of four treatments, V1 (AVON), V2 (S-2000), V3 (S-2011) and V4 (PD2LV65) and the second approach was seed inoculation consisting of three treatments, S0 (control), S1 (Azotobacter spp.), S2 (Azospirillum spp.). Fisher’s analysis of variance technique was used for statistically interpretation of data by using least significant difference (LSD) test at 5% level of probability. Nitrogen fixing bacteria significantly affect the germination count (m2), plant height (cm), number of tillers (m2), number of leaves per tiller, leaf area per tiller (cm2), green forage yield (t·ha-1) and dry matter yield (t ha-1). The maximum green forage yield (85.2 t·ha-1), dry matter yield (14.1 t ·ha-1) and crude protein (11.5%) were recorded where Azotobacter inoculation was applied. The interaction between cultivars and nitrogenous strains was significant for green forage yield (t·ha-1), dry matter yield (t·ha-1) and crude protein (%). Conclusion showed that cultivar Sargodha-2011 which was inoculated with Azotobacter spp. gave higher forage yield of good quality.

Effects of Dietary Concentrate to Forage Ratios on Production Performance and Serum Biochemical Indicators in Post-fattening Hainan Yellow Cattle

[Objective]The paper was to investigate the effects of dietary concentrate to forage ratios on production performance and serum bio-chemical indicators of post-fattening Hainan Yellow Cattle.[Method]Sixteen Hainan Yellow Cattles with the same genetic backgrounds and similar initial weight of(242.22 ±0.71 kg) were randomly divided into four treatments.Cattles were fed with diets of different concentrate to forage ratios(20:80, group Ⅰ;30:70, Group Ⅱ;40:60, group Ⅲ;50:50, group Ⅳ).The trial lasted 62 d.[Result]The daily gain in experimental group Ⅳ was significantly higher than that in experimental group Ⅱ(P<0.05), but the feed gain ratio in experimental group Ⅳ was lower than those in other ex-perimental groups(P>0.05).The feed intake in experimental group Ⅳ was also markedly higher than those in experimental groups Ⅰ and Ⅱ(P<0.05).Compared with the experimental group Ⅱ, the gross profit of experimental group Ⅳ was significantly promoted(P<0.05).The alanine aminotransferase and aspartate aminotransferase activities in experimental group Ⅱ were markedly higher than those in experimental groups Ⅰ, Ⅲ and Ⅳ.[Conclusion]When the dietary concentrate to forage ratios was 50∶50, the production performance of post-fattening Hainan Yellow Cattle was better.

QTL analysis of the developmental changes in cell wall components and forage digestibility in maize(Zea mays L.)

Cell wall architecture plays a key role in stalk strength and forage digestibility.Lignin,cellulose,and hemicellulose are the three main components of plant cell walls,and they can impact stalk quality by affecting the structure and strength of the cell wall.To explore cell wall development during secondary cell wall lignification in maize stalks,conventional and conditional genetic mapping were used to identify the dynamic quantitative trait loci(QTLs)of the cell wall components and digestibility traits during five growth stages after silking.Acid detergent lignin(ADL),cellulose(CEL),acid detergent fiber(ADF),neutral detergent fiber(NDF),and in vitro dry matter digestibility(IVDMD)were evaluated in a maize recombinant inbred line(RIL)population.ADL,CEL,ADF,and NDF gradually increased from 10 to 40 days after silking(DAS),and then they decreased.IVDMD initially decreased until 40 DAS,and then it increased slightly.Seventytwo QTLs were identified for the five traits,and each accounted for 3.48–24.04%of the phenotypic variation.Six QTL hotspots were found,and they were localized in the 1.08,2.04,2.07,7.03,8.05,and 9.03 bins of the maize genome.Within the interval of the pleiotropic QTL identified in bin 1.08 of the maize genome,six genes associated with cell wall component biosynthesis were identified as potential candidate genes for stalk strength as well as cell wall-related traits.In addition,26 conditional QTLs were detected in the five stages for all of the investigated traits.Twenty-two of the 26 conditional QTLs were found at 30 DAS conditioned using the values of 20 DAS,and at 50 DAS conditioned using the values of 40 DAS.These results indicated that cell wall-related traits are regulated by many genes,which are specifically expressed at different stages after silking.Simultaneous improvements in both forage digestibility and lodging resistance could be achieved by pyramiding multiple beneficial QTL alleles identified in this study.

Progress in Relationship between Anatomical Structures of Vegetative Organs and Drought Resistance in Forage Germplasm Resources

The anatomical structures of roots, stems and leaves are very important indicators to＇evaluate drought resistance. The paper reports the relationship between anatomical structures of vegetative organs and drought resistance in forages.