Chemical Composition Of Grass Research Articles

50 Water-soluble carbohydrate content in equine pasture: Impact of fertilization, season, and grass species

Horses spend a significant proportion of time grazing to meet their nutritional requirements. However, many domesticated horses now graze on energy-dense pastures designed to support production animals. Excessive consumption of these pastures that often contain significant quantities of water-soluble carbohydrates (WSC) has been linked to the development of pasture-associated laminitis. Although seasonal changes in pasture WSC content are well documented, the impact of fertilization or grass species composition are less defined. To evaluate the effect of season and fertilization on WSC concentrations, grassland plots were established at SRUC Aberdeen, UK. Six distinct cool-season seed mixtures (Table 1) were sown in triplicate plots (3m x 4m) and split in half to evaluate the effect of fertilizer treatment (285kg/ha of 21–8-11, annual application in March). Samples were collected on ice at set 6-to-8-week intervals (May–October) across 2 consecutive years. The Anthrone method was employed to estimate WSC content of lyophilised and milled samples, expressed as glucose and fructose equivalents [g/kg DM]. Independent t-test analysis (significance set at P < 0.05) revealed that fertilization had no overall effect on the WSC fraction for glucose (t(94) = 1.02, P = 0.99, 95% CI [-7.57, 23.51]) or fructose (t(94) = 1.28, P = 0.78, 95% CI [-4.69, 21.85]). Analysis of variance analysis demonstrated a significant effect of seed mixture (F = 2.56, P = 0.033 for glucose, F = 2.39, P = 0.044 for fructose) and season (glucose: F = 21.88, P = < 0.001, fructose:F = 21.09, P = < 0.001). WSC concentration was highest in samples collected in Spring, while the perennial rye grass mix (5) and a diverse herb mix (4) had the highest and lowest WSC contents across all samples, respectively. These preliminary results suggest that season and grass species composition have a greater effect on WSC concentrations in pasture than fertilizer treatment. Further studies are warranted to estimate the impact of fertilizer on other aspects of grass chemical composition that may have implications for managing pasture for grazing animals.

Morphological and Productive Characteristics and Chemical Composition of Grasses in Degraded Areas Subjected to Pasture Recovery Methods

The objective of this study was to evaluate the morphological characteristics, yield and chemical composition of grasses in degraded areas subjected to pasture recovery methods. The randomized block design in a factorial scheme (4 × 5) with four replications (blocks) was used. The first factor was composed of four methods of pasture recovery: Closed pasture (CLP); Weed control (WC); Soil fertilization (SF); and Weed control + Soil fertilization (WC + SF). The second factor was composed of five species used for pasture recovery: Brachiaria brizantha cv. Marandu, Brachiaria brizantha cv. MG5, Brachiaria brizantha cv. MG4, Andropogon gayanus cv. Planaltina and Panicum maximum cv. Mombaça. The structural characteristics of green biomass yield, dry biomass yield and chemical composition were assessed in those grasses. An effect of the interaction (p &lt; 0.05) between forage species and recovery methods on number of clumps, plant height and clump diameter, with superiority for cultivar MG4 in the WC + SF method. The green biomass yield was low in the evaluated grasses because of the advanced stage of the degradation of the pastures. Dry biomass yields increased (p &lt; 0.05) when the WC + SF method was adopted, with a good response of grass MG4. There was an interaction (p &lt; 0.05) between species and recovery methods on dry matter, mineral matter and neutral detergent fiber contents of the grasses, especially Marandu grass. The different types of grasses responded positively to the methods of pasture recovery with increased biomass and nutritional quality.

Алматы облысының тау бөктерлерінде мекендейтін сарышұнақтың қорек құрамының ерекшеліктері

The article provides information about features of the chemical and mineral composition of the diet of ground squirrels living in the foothills of the Trans-Ili Alatau. The study was conducted in 2020 on the foothill-steppe, foothill-dry steppe, foothill-desert pastures of festuca-bluegrass-carex, ephemeral-wormwood, sainfoins-bromus-festuca, stipa-bluegrass-wormwood, cereal-wallflower-garlic, wormwood-ceratocarpus. The main research method-the study of the fertility and chemical composition of grasses was carried out by generally accepted methods of zootechnical analysis. It was conducted in the laboratory of KazRILFP LLP (Kazakh research institute of livestock and fodder production). The chemical, mineral and nutritional properties of the food were studied and determined depending on the different growth phases. Samples of natural grasses of foothill areas of Almaty region were studied 5 times during the growing season, from May to September. Results obtained showed that, regardless of the growth zone, the nutritional value of the feed unit and the digestible protein are determined during the tube release period. Later, it decreases slightly during the earing period, and a decrease in the nutritional value of plants occurs during the flowering period and after flowering. Along with the decrease in nutritional value, the content of dry substances and fiber increases. In combination with the level of raw and digestible protein, the carotene content also decreases during the growing season of herbs. In this regard, the change in the composition of the yellow ground squirrel's diet and its value directly depend on the growing season of pasture grasses and the composition of the rodent's diet changes.

Estimating Plant Pasture Biomass and Quality from UAV Imaging across Queensland’s Rangelands

The aim of this research was to test recent developments in the use of Remotely Piloted Aircraft Systems or Unmanned Aerial Vehicles (UAV)/drones to map both pasture quantity as biomass yield and pasture quality as the proportions of key pasture nutrients, across a selected range of field sites throughout the rangelands of Queensland. Improved pasture management begins with an understanding of the state of the resource base, UAV based methods can potentially achieve this at improved spatial and temporal scales. This study developed machine learning based predictive models of both pasture measures. UAV-based structure from motion photogrammetry provided a measure of yield from overlapping high resolution visible colour imagery. Pasture nutrient composition was estimated from the spectral signatures of visible near infrared hyperspectral UAV sensing. An automated pasture height surface modelling technique was developed, tested and used along with field site measurements to predict further estimates across each field site. Both prior knowledge and automated predictive modelling techniques were employed to predict yield and nutrition. Pasture height surface modelling was assessed against field measurements using a rising plate meter, results reported correlation coefficients (R2) ranging from 0.2 to 0.4 for both woodland and grassland field sites. Accuracy of the predictive modelling was determined from further field measurements of yield and on average indicated an error of 0.8 t ha−1 in grasslands and 1.3 t ha−1 in mixed woodlands across both modelling approaches. Correlation analyses between measures of pasture quality, acid detergent fibre and crude protein (ADF, CP), and spectral reflectance data indicated the visible red (651 nm) and red-edge (759 nm) regions were highly correlated (ADF R2 = 0.9 and CP R2 = 0.5 mean values). These findings agreed with previous studies linking specific absorption features with grass chemical composition. These results conclude that the practical application of such techniques, to efficiently and accurately map pasture yield and quality, is possible at the field site scale; however, further research is needed, in particular further field sampling of both yield and nutrient elements across such a diverse landscape, with the potential to scale up to a satellite platform for broader scale monitoring.

Chromato-mas-spectroscopic study of the chemical composition of growing in ukraine Tanacetum corymbosum (L.) Sch. Bip. populations

The aim of the work was the chromato-mas-spectroscopic studyof the chemical composition of Tanacetum corymbosum (L.) Sch. Bip. and the identification of further prospects for the use of raw materials of this plant in medical and pharmaceutical practice.Materials and methods. The object of the study was the grass of Tanacetum corymbosum (L.) Sch. Bip., which was collected in Zaporizhzhia in July 2019. The method of high-performance gas chromatography on the device Agilent 7890B GC System (Agilent, Santa Clara, CA, USA) with mass spectrometry detector Agilent 5977 BGC/MSD (Agilent, Santa Clara, CA, USA) was used to determine the chemical composition of Tanacetum corymbosum (L.) Sch. Bip. The NIST14 mass spectrum library was used to identify the components.Results. There were 42 components, which were contained in the grass of Tanacetum corymbosum (L.) Sch. Bip. (2 are isomers). They belong to different classes of biologically active substances. There were: terpenoids (39.53 %), heterocyclic compounds (34.75 %), fatty acids and their derivatives (9.78 %), hydrocarbons (7.23 %), alcohols (5.61 %), aldehydes and ketones (0.74 %).2H-Cyclohepta[b]furan-2-one,3,3a,4,7,8,8a-hexahydro-7-methyl-3-methylene-6-(3-oxobutyl)-, [3aR-(3a.alpha.,7.beta.,8a.alpha.)]- was constituted the main part among all found compounds – 24.46 %, (+)-2-bornanone (11.85 %) and bicyclo[3.1.1]hept-2-en-6-ol, 2,7,7-trimethyl-, acetate, [1S-(1.alpha.,5.alpha.,6.beta.)]- (16.27 %) are next.Also, n-tetracosanol-1 and 4H-1-benzopyran-4-one, 2-(3,4-dimethoxyphenyl) -5-hydroxy-3,6,7-trimethoxy- were presented in quantity 4.78 % and 4.48 % respectively.Considering all of the above and information, which was obtained from publications of Ukrainian and foreign authors, further prospects for the use of Tanacetum corymbosum (L.) Sch. Bip. in medical and pharmaceutical practice can be considered.Conclusions. The chemical composition of grass of Tanacetum corymbosum (L.) Sch. Bip. was established by method of gas chromatography with mass spectrometry detector. 42 components were identified (2 in the isomeric state). They belong to different groups of biologically active substances: terpenoids, heterocyclic compounds, fatty acids and their derivatives, hydrocarbons, alcohols, aldehydes and ketones. Considering the biological properties of the main active ingredients, the raw materials of Tanacetum corymbosum (L.) Sch. Bip. can be considered as a promising source of antioxidant, antimicrobial and anti-inflammatory drugs.

Rumen cannulation of young cattle depending on protein diet

An experiment has been carried to determine the degradable and non-degradable protein content in grass and concentrated feed and its influence on operated sire rumen cannulation of black-and-white breed (with body weight of 120–160 kg). The grass chemical composition and concentrated feed research shows that there is a wide range of crude protein content and its degradable and non-degradable fractions. The level of crude protein in concentrated feed varies from 96 g (barley grain) to 380–383 g (extruded lupine grain and rapeseed meal). The amount of degradable protein is 81 (barley grain), 303 g (rapeseed meal). Degradability of crude protein ranges from 57 % (extruded rapeseed) to 84–86 % (barley and wheat grain). The crude protein content in the presented samples of grass feed is 27 (corn silage) – 93 g (cereal hay), degradable protein – from 17–19 (cereal hay and corn silage), up to 38 g (mixed grass), non-degradable – 8 (corn silage, 76 g (cereal hay). The degradable and non-degradable protein ration was 2:7. The crude protein increase in summer and winter calve diet up to 70 % contributes a lower accumulation of ammonia in the rumen fluid (by 19.6–20.6 % ) and activation of VFA synthesis (by 16.5–18.2). It also contributes the increase of the ciliate number (by15,7–15,9), total and protein nitrogen (by 7.2–7.4 and 8.0–12.3 %). Feeding on protein degradability (of 65–60 %) lets the rumen metabolism processes slow down, reduce the microbiota enzyme activity, the protein nitrogen proportion and the ammonia level increasing. According to the analysis results of economic diet indices with different protein fractional composition it has been determined that the ration use with protein degradability of 70 %, and metabolizable energy costs – by 4.0–5.0 % are economically reasonable in summer and winter periods. Key words: concentrated feeds, grain, degradable protein, non-degradable protein, calves.

The study of chemical composition of Centaurea diffusa Lam.

The aim of the work is to study the chemical composition of biologically active compounds of Centaurea diffusa Lam . and the future prospects of its application in the medical and pharmaceutical practice. Materials and methods. The object of the study is the grass of Centaurea diffusa Lam., which was collected in Zaporizhia in July 2018. The method of high-performance gas chromatography on the device Agilent 7890B GC System (Agilent, Santa Clara, CA, USA) with mass spectrometry detector Agilent 5977 BGC / MSD (Agilent, Santa Clara, CA, USA) was used to determine the qualitative and quantitative composition of Centaurea diffusa Lam. Results. It was discovered that raw material of Centaurea diffusa Lam. contains 55 components, which are representatives of different classes of biologically active substances. There are phenols – 9, alcohols – 9, carboxylic acids (saturated and unsaturated) – 8, esters – 7, alkanes – 5, heterocyclic compounds – 4, ketones – 4, terpenes – 3, aldehydes – 2, alkenes – 1, monosaccharides – 2, hydrazides – 1. However, these data differ from the total content of compounds by percentage. Phenols make up 21.45 % and this is the highest indicator, carboxylic acids (saturated and unsaturated) are 19.71 %, and alcohols and esters are 17.63 % and 12.43 % respectively. Retusin constitutes the main part among all found compounds – 15.53 %, 4-hexadecanoic acid (12.25 %) and 2-ethyl-2-(hydroxymethyl)-1,3-propanediol (8.17 %) are on the second and third place. It’s useful to note that hexadecanoic acid 2-hydroxy-1-(hydroxymethyl)ethyl ester is present in quantity 4.3 %. Based on the results obtained, it is possible to consider the further prospects of using Centaurea diffusa Lam. in medical and pharmaceutical practice. Conclusions. The chemical composition of grass of Centaurea diffusa Lam. was first set by the method of gas chromatography with mass spectrometry detector. The presence of 55 biologically active components was determined. The experimental results prove the prospects and relevance of studies the chemical composition of Centaurea diffusa Lam. in order to create new herbal remedies based on it.

The interrelations of herbage productivity with mouse-like rodents and forest litter in linden and ash flood oak grove of Prysamar'ya

The relationships between the productivity of herbage as one of the structural elements of forest biogeocenosis with the nature of the formation and chemical composition of the forest litter and the activity of mouse-like rodents in linden and ash flood oak grove of Prysamar’ya were investigated. It was found that leaf-litter affects to the species composition and the degree of development of grass of investigated biogeocenose. It was revealed that the trophic removal of herbage phytomass by mouse-like rodents in the initial period of vegetation promotes its products. As a result, the above-ground herbage on rodent habitats increases by 1.2 times. The alienation of above-ground herbal phitomass in natural conditions under the influence of mouse-like rodents in the middle of the vegetation season increases in areas devoid of rodents’ influence by 1.05 times. It was found that in the final vegetation season, the above-ground herbage at the rodents’ exposure sites decreases by 1.3 times. It was investigated that the above-ground herbage for the whole vegetation season in the natural conditions of the flood oak grove was 115.4 g/m2, and in experimental areas, devoid of rodents’ exposure was 124.0 g/m2. Thus in the study biogeocenosis the value of herbage productivity was under the influence of mouse-like rodents and it reduced to 1.07 times during the whole growing period. In turn, the grass contributes to the increase in stocks of leaf-litter, ash elements including trace elements in forest litter. The quantitative proportion of herbaceous plants in leaf-litter and the chemical composition of grass in two synusias (wild chervil and starwort) were studied. It was revealed that the air-dry weight of the above-ground parts of herbage in synusia of wild chervil was higher than in synusia of starwort. It was determined that the accumulation degree of individual trace elements varies in different species of herbaceous plants. The maximum content of Mn, Pb and Cu more at wild chervil and Ti, Mo, V, Ni and Cr maximum contents were marked at starwort.

Use of Organic Compost for the Fertilization of Piatã and Paiaguás Grasses: Effects of Dose on Morphogenetic, Structural, Nutritional, and Productive Characteristics

ABSTRACTThe use of organic compost in pasture fertilization is a form of recycling nutrients contained in waste and reducing chemical fertilizer use. To perform pasture fertilization, however, grass responses to doses of organic composts must be known. Thus, the objective of this study was to find the best dose of laying hen organic compost to maximize the productive, morphogenetic, structural, and nutritional responses of Paiaguás and Piatã grasses. A completely randomized factorial (4 × 2) design was used, composed of organic compost doses (0, 400, 800, and 1,200 kg equivalent N.ha−1) and two cultivars (Piatã and Paiaguás) of Urochloa brizantha grass with three replicates per treatment, assessed during four successive cuts. The parameters evaluated were dry matter yield (DM) of shoots and roots, leaf appearance rate (LAR), leaf elongation rate (LER), phyllochron, pseudoculm elongation rate (PER), final leaf length (FLL), number of green leaves (NGL), and senescence rate (SR). The nutritional value of the grasses was also assessed through contents of dry matter, organic matter, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber, cellulose, hemicellulose, lignin, and in vitro organic matter digestibility (IVOMD). DM yields of both shoot and root increased due to nitrogen increase and Paiaguás grass had the highest yields (P < 0.01). The best organic compost doses ranged from 640 to 950 kg of equivalent N.ha−1 for most morphogenic and structural grass characteristics. The chemical composition of grasses was not influenced (P > 0.05) by doses of organic compost. Levels of 8.05% CP, 67.10% NDF, and 65.14% IVOMD were observed for cultivar Paiaguás, while for cultivar Piatã these values were 7.58% CP, 70.32% NDF, and 63.38% IVOMD. It is concluded that high doses of an organic compost are required (in equivalent N) for cultivars to reach the highest growth rates and that Paiaguás grass has higher dry matter yield, higher growth rates, and better chemical composition when compared to Piatã grass in similar organic fertilization conditions.

&lt;b&gt;Production and chemical composition of grasses and legumes cultivated in pure form, mixed or in consortium

The objective of this study was to assess the edible biomass and chemical composition of forages grown on pure form, as a grass mix, and in grass-legume consortia. The following species were tested: white oats ( Avena sativa ), black oats ( Avena strigosa ), ryegrass ( Lolium multiflorum ), forage peanut ( Arachis pintoi ), white clover ( Trifolium repens ), and red clover ( Trifolium pratense ). The experiment consisted of sixteen treatments arranged in a completely randomized design. The parameters measured were total dry matter (PMST), neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude protein (CP). No significant differences in PMST were found among the consortia (p > 0.05). Only the pure cultivated white clover (p > 0.05) was comparable to the consortia in terms of biomass production. The three legumes had the lowest average NDF values (p > 0.05), based on their contributions to the total NDF content of the consortia along the cuts. The ADF content increased for all treatments during the cuts. The results indicate that in pasture, legumes increase protein content, and forage consortia increase both the pasture production and the grazing period. Their chemical composition is adequate for boosting livestock production in pastures.

The effect of seaweed Ecklonia maxima extract and mineral nitrogen on fodder grass chemical composition.

The objective of this study was to determine the effect of the biostimulant Kelpak and different nitrogen rates on cellulose, hemicellulose and lignin contents as well as non-structural carbohydrates in orchard grass and Braun’s festulolium. The experiment was a split-plot arrangement with three replicates. It was set up at the experimental facility of the University of Natural Sciences and Humanities, Siedlce, in late April 2009. The following factors were examined: biostimulant with the trade name Kelpak SL applied at 2 dm3 ha−1 and a control—no biostimulant; nitrogen application rates 50 and 150 kg ha−1 and a control (0 kg ha−1); pure stands of grass species grown in monoculture—orchard grass (Dactylis glomerata), cv. Amila,—Braun’s festulolium (Festulolium braunii), cv. Felopa. Kelpak significantly increased non-structural carbohydrates, and increasing nitrogen rates reduced the concentration of these components in plants. Increasing nitrogen rates significantly decreased cellulose, hemicellulose, lignin and non-structural carbohydrate contents. Compared with orchard grass, Braun’s festulolium proved to be of a higher nutritional value due to lower cellulose, hemicellulose and lignin contents and more non-structural carbohydrates. The aforementioned contents in the grasses differed significantly depending on the cut. Most cellulose and non-structural carbohydrates were determined in second-cut grass whereas most hemicellulose and lignin in second-cut grass.

Prediction of nutrient digestibility and energy concentrations in fresh grass using nutrient composition

Improved nutrient utilization efficiency is strongly related to enhanced economic performance and reduced environmental footprint of dairy farms. Pasture-based systems are widely used for dairy production in certain areas of the world, but prediction equations of fresh grass nutritive value (nutrient digestibility and energy concentrations) are limited. Equations to predict digestible energy (DE) and metabolizable energy (ME) used for grazing cattle have been either developed with cattle fed conserved forage and concentrate diets or sheep fed previously frozen grass, and the majority of them require measurements less commonly available to producers, such as nutrient digestibility. The aim of the present study was therefore to develop prediction equations more suitable to grazing cattle for nutrient digestibility and energy concentrations, which are routinely available at farm level by using grass nutrient contents as predictors. A study with 33 nonpregnant, nonlactating cows fed solely fresh-cut grass at maintenance energy level for 50 wk was carried out over 3 consecutive grazing seasons. Freshly harvested grass of 3 cuts (primary growth and first and second regrowth), 9 fertilizer input levels, and contrasting stage of maturity (3 to 9 wk after harvest) was used, thus ensuring a wide representation of nutritional quality. As a result, a large variation existed in digestibility of dry matter (0.642–0.900) and digestible organic matter in dry matter (0.636–0.851) and in concentrations of DE (11.8–16.7 MJ/kg of dry matter) and ME (9.0–14.1 MJ/kg of dry matter). Nutrient digestibilities and DE and ME concentrations were negatively related to grass neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents but positively related to nitrogen (N), gross energy, and ether extract (EE) contents. For each predicted variable (nutrient digestibilities or energy concentrations), different combinations of predictors (grass chemical composition) were found to be significant and increase the explained variation. For example, relatively higher R2 values were found for prediction of N digestibility using N and EE as predictors; gross-energy digestibility using EE, NDF, ADF, and ash; NDF, ADF, and organic matter digestibilities using N, water-soluble carbohydrates, EE, and NDF; digestible organic matter in dry matter using water-soluble carbohydrates, EE, NDF, and ADF; DE concentration using gross energy, EE, NDF, ADF, and ash; and ME concentration using N, EE, ADF, and ash. Equations presented may allow a relatively quick and easy prediction of grass quality and, hence, better grazing utilization on commercial and research farms, where nutrient composition falls within the range assessed in the current study.

The effect of saturation of the soil absorbing complex with cations on the yield and chemical composition of grasses

Three year long pot experiments using medium sand were conducted with a Italian ryegrass, &lt;i&gt;Lolium multiflorum&lt;/i&gt;. Two year pot experiments were also done on medium soil with meadow fescue, &lt;i&gt;Festuca pratensis&lt;/i&gt;. Before the experiment was begun, the absorbing complexes of these soils were saturated with cations to very different degrees. The results of these experiments showed that the degree of saturation of the absorbing complexes with potassium and magnesium should increase as the size of the complex decreases. Increasing doses of potassium significantly widened the K : (Ca + Mg) ratio in grasses and lowered their quality, while Ca and Mg slightly narrowed this ratio. However, it was not wider than the acceptable ratio, even with the highest K doses.

NUTRITIVE VALUE OF GREEN MASS AND HAY FROM THE DIVČIBARE REGION

With the aim of forming a complete observation of the botanical composition and nutritive value of pasture and meadow hay from the Divcibare region, which is a typically hilly-mountain area in Serbia, investigations were designed to evaluate the quality of pasture and hay (chemical composition and energy value), as well as the losses which are results of drying pasture. Twelve samples of grass were taken from three different altitudes and after mowing, samples of hay were also taken from the same meadow. In a conventional chemical analysis (Weende) the chemical composition of grass and hay were determined. On the basic of this analysis nutritive values were calculated. Pasture and hay from the Divcibare region have a satisfying chemical composition, they can be used as a forage base and a source of nutrients for ruminants, predominantly, lowproducing livestock. The difference in content of proteins among samples from some localities might be bound with the content of fabaceae. The increase fibre content with the proportional decrease content of protein had a negative influence on the nutritive value in the samples of grass and hay. The Net Energy Lactation (NEL) of hay from the investigated region is near the lower limit reported as average for pasture and meadow hay. Significant higher nutritive values of green mass, calculated on dry matter (NEL 8.35 MJ/kg, SV 0.78 SJ/kg) when compared to the nutritive value of hay (NEL 8.12 MJ/kg, SV 0.74 SJ/kg) show that losses are results of haymaking. Nutrients losses during drying are in correlation with losses of proteins, lipids and mineral matter, but there is an increase in fiber. The change in chemical composition due to the described losses during drying and the negative influence on organic matter digestibility, led to a reduction in the energy value of the investigated samples.

Changes of chemical composition and nutritive values of Reed Canary Grass (Phalaroides arundinacea) in first growth

Change in chemical composition and nutritive value of Reed Canary Grass (Phalaroides arundinacea) were investigated in springtime in 2004-2006. The nutritive value of Reed Canary Grass was observed between the end of April and the middle of June relating to the following parameters: crude protein, crude fibre, crude fat, ash, N-free extract, net-energy growth, net-energy maintenance, Metabolizable Protein Energy dependent,Metabolizable Protein N-dependent.It was also analysed whether a relationship between the climatic factors affecting the growing period as well the chemical composition of grasses and the annual weather were looked for. For the estimation of weather conditions the climate index was calculated. A correlation can be detected between the change of parameters of nutritive value and the quality of the current year. Between 2004 and 2006, the result of the analysis of nutritive value indicated a significant difference with respect to each chemical composition at the rate of P&lt;0.01 depending on the time when the samples were taken. According to the outlined data it can be stated that the change of the value of crude protein and ash show decreasing endency agreeing the research literature. In parallel with the change of nutritive value, the amount of crude fibre and N-free extract increased. However, the value of Net-Energy maintenance revealed an alteration only in the first half of the observed period. The same alteration tendency can be detectedin the Net-Energy growth.

Effect of daily movement of dairy cattle to fresh grass in morning or afternoon on intake, grazing behaviour, rumen fermentation and milk production

SUMMARYTwenty Holstein cows were split into two equal groups to test the effect of daily move to a previously ungrazed strip after morning milking (MA) or afternoon milking (AA) on herbage intake, grazing behaviour, rumen characteristics and milk production using a randomized block design with three periods of 14 days each. Milking took place at 06.00 and 16.00 h. The chemical composition of grass was similar between treatments, but an interaction between treatment and time of sampling was found in all variables except acid detergent lignin (ADL). The most pronounced differences existed in sugar content. Grass sugar content was greatest following afternoon milking. However, the difference in sugar content in grass was much larger in MA (158v114 g/kg dry matter (DM) at 16.00 and 06.00 h, respectively) than in AA (147v129 g/kg DM at 16.00 and 06.00 h, respectively). Neutral detergent fibre (NDF) was significantly higher at 06.00 h than at 16.00 h (469v425 g/kg DM) in AA, but was equal between morning and afternoon in MA (453 g/kg DM). Herbage intake, determined using the n-alkane technique, did not differ between treatments. Grazing behaviour observed using IGER graze recorders were similar between treatments, except for ruminating time, bite rate and the number of ruminations and boli per period of the day. However, interactions between treatment and time in grazing behaviour variables were found. Grazing time was longer and number of bites was greater following allocation to a new plot (after milking in the morning in MA or milking in the afternoon in AA) when compared to allocation to the same plot after the subsequent milking per treatment (after milking in the afternoon or morning in MA and AA, respectively). In comparison to AA, grazing time in MA was more evenly distributed during the day but lower during the night. The combined effects of differences in grazing behaviour and chemical composition of the grass between treatments in different periods of the day probably caused higher intake of sugars in AA, resulting in a significantly higher non-glucogenic to glucogenic volatile fatty acid ratio (NGR) in the rumen in AA than MA. Milk fat content was lower in MA than AA, but milk production and milk protein and lactose content did not differ. In conclusion, time of allocation to a fresh plot altered the distribution of grazing behaviour variables over the day, and affected NGR and milk fat content, but herbage intake and milk production were not changed.

Methane emission from dairy cows and wether sheep fed subtropical grass‐dominant pastures in midsummer in New Zealand

Methane emission was measured from 10 dairy cows and 12 wether sheep grazing kikuyu grass‐ (Pennisetum clandestinum) dominant pastures at Waimate North, Northland, in February 1997 and March 1999, and from 10 dairy cows grazing summer grass‐ (Digitaria sanguinalis) dominant pasture at Edgecumbe, Bay of Plenty, in March 2000. Methane emission was measured from each animal for 5 consecutive days in each measurement period using the sulphur hexafluoride (SF 6 ) tracer gas technique. Analysis of variance of the kikuyu grass chemical composition with sheep and cow data combined showed that the 1999 pastures were significantly higher in protein (P < 0.01), soluble sugars (P < 0.001), lipid (P < 0.01), and dry matter (DM) digestibility (P < 0.001) and lower in ash (P = 0.023), acid detergent fibre (ADF) (P < 0.001), and neutral detergent fibre (NDF) (P < 0.001) than the 1997 pastures, presumably as a consequence of urea topdressing in 1999. The chemical composition of the summer grass‐dominant pasture grazed by cows in 2000 was similar to the kikuyu grass, except that DM digestibility was higher. Daily methane emissions from kikuyu grass were 363 and 167 g/day for the cows and 15.6 and 4.4 g/day for the sheep in 1997 and 1999, respectively. These corresponded to methane yields (MYs, methane energy as a percentage of gross energy) of 7.1 and 3.8% for the cows and 6.3 and 1.9% for the sheep in 1997 and 1999, respectively. There was clearly a significant inhibition (P < 0.001) of methane production in 1999 in both species fed kikuyu grass. Methane emission was 422 g/day and MY 6.7% in the cows fed summer grass, values that were similar to the kikuyu‐fed cows in 1997. Methane emitted in g/kg digestible DM intake was 33.8 and 38.2 for the 1997 kikuyu grass‐fed cows and sheep and 33.3 for the summer grass‐fed cows. This suggests that methane emitted per unit of digested DM is higher for ruminants fed subtropical (C4) grasses than those fed temperate (C3) grasses and we believe it to be related to the higher cell wall content of C4 grasses.

Nutritional quality of semi‐arid grassland in western Spain over a 10‐year period: changes in chemical composition of grasses, legumes and forbs

From 1987 to 1996, the nutritional quality of the main botanical components (grasses, legumes and forbs) in semi‐arid grasslands in the dehesa ecosystem in western Spain was analysed. Herbage samples were collected at the end of spring, in 30 locations, at two different topographic positions (upper and lower slope zones). Herbage mass over 2 cm and proportion of botanical components were estimated and samples were analysed for crude protein, neutral‐detergent fibre (NDF), hemicellulose, cellulose, lignin and in vitro dry matter digestibility (DMD). Analysis of variance revealed a significant effect of sampling year on the herbage mass, proportion of botanical components and their nutritional quality. The three botanical groups, grasses, legumes and forbs, followed similar year‐to‐year trends in their crude protein, cellulose and lignin contents and in vitro DMD. Herbage mass was not significantly related to any meteorological variables, suggesting that interannual variation in biomass production of botanically complex pastures cannot be explained by a single factor. However, annual precipitation was significantly related to the proportion of the botanical group that was dominant at each slope zone: grasses in the lower zone and forbs in the upper zone. In the upper zone, spring precipitation explained part of the interannual variation in the NDF, cellulose, lignin contents and in vitro DMD of the botanical components.

The effect of level of inclusion of the legume Desmodium uncinatum and the use of molasses or ground maize as additives on the chemical composition of grass- and maize-legume silages

The effect of the inclusion rate of legume and use of molasses or ground maize as additives on the chemical composition of grass- and maize-legume silages was investigated in two experiments. In experiment 1 the effects of adding molasses or ground maize to star grass ( Cynodon nlemfluensis) with or without legume ( Desmodium uncinatum) at ensiling were studied. Four additive treatments (no additive, molasses, 50 and 100 g ground maize/kg fresh weight) were combined with four levels of legume (no legume, 150, 300 and 450 g/kg fresh weight) in a factorial arrangement of treatments. Sealed plastic bags containing about 15 kg of compressed material were used and each treatment was replicated three times. In experiment 2 the effect of adding graded levels of legume ( D. uncinatum) to maize ( Zea mays) at ensiling was studied in a completely randomised block design. Four levels of legume were used at ensiling: no legume, 150, 300 and 450 g/kg fresh weight. The same procedure as that used in experiment 1 was applied. All the grass silages were well fermented. Addition of ground maize and molasses increased the dry matter content of grass silage ( P < 0.001). Molasses addition resulted in lower ( P < 0.05) levels of volatile nitrogen and higher ( P < 0.05) lactic acid content compared to the control and the ground maize treatments. The inclusion of legume above 300 g/kg fresh weight raised the pH, volatile nitrogen and total nitrogen content of grass silages ( P < 0.001). The increase in pH and volatile nitrogen content was less when the silages were treated with additive, especially molasses. All the maize silages were well fermented, with low pH and volatile nitrogen levels. Crude protein level was increased from 60 to 90 g/kg dry matter in the silage with no legume and at the highest level of legume (450 g/kg) respectively. The pH increased from 3.7 in silages with no legume to 4.2 when legume was added at the rate of 450 g/kg. The inclusion of D. uncinatum improved the quality of both grass and maize silages. However, the inclusion of legume above 300 g/kg fresh weight of grass silage would require the use of additives.

Effects of Sodium Fertiliser on the Chemical Composition of Grass and Clover Leaves, Stems and Inflorescences

Sodium fertiliser was applied to dairy cow pasture to investigate the effects on the chemical composition of grass and clover leaves, stems and inflorescences. The effect of sodium fertiliser varied between fractions, with grass leaves and stems generally being more responsive than grass inflorescences or clover fractions. The sodium content of all fractions was already high in the control treatment, and was increased to an excessive level by sodium fertiliser in all fractions except grass stems. Grass leaves were most affected. Potassium content was reduced in grass leaves and stems, but not in other fractions. The effects on calcium and magnesium varied between fractions but the K: (Ca+Mg) ratio, the most sensitive index of susceptibility to hypomagnesaemia, was reduced in grass leaves, but increased in other fractions. DM digestibility was decreased in grass and clover leaves by sodium, probably because of the high sodium content. MAD fibre content was also increased in these fractions. Crude protein content was decreased by sodium fertiliser in grass leaves, in particular. Therefore, when applied to pasture which is naturally high in sodium, sodium fertiliser had detrimental effects on pasture macronutrient content. However, beneficial effects were still observed on mineral ratios for plant and animal nutrition. It is concluded that if sodium fertiliser increases herbage sodium concentrations above 5 g kg−1 DM, improvements in mineral ratios that could affect ruminant health may be offset by reductions in the nutritive value of the herbage. It is therefore recommended that the herbage sodium concentration should be known before sodium fertiliser is applied.