bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of crown rust (Puccinia coronata) on tiller production and survival of perennial ryegrass (Lolium perenne) plants in simulated swards
Authors: PLUMMER R. M. , HALL R. L. , WATT T. A. 
Published: April 2006

AbstractPopulations of Aberystwyth S23 and S24 ryegrass tillers were individually labelled and harvested at intervals to follow their life histories and productivity in response to the effect of infection with crown rust at two levels of nitrogen fertilization.The number of tillers in a population was reduced as a result of infection with crown rust. Increased rates of tiller death due to the pathogen occurred throughout the population age‐range and were most pronounced in the youngest tillers. Population changes were evident following infection and continued to be apparent in the following spring. The disease caused alterations in sward age structure, leading both to a higher proportion of older tillers in the more rust‐damaged treatments and to a decrease in the weight of the herbage produced. It is concluded that rust infection of a sward may lead to changes in population structure with long‐term yield effects, in addition to the immediate direct yield reductions commonly reported. The significance of these results to the ecological and agronomic balance of grassland is discussed.
Contribution of white clover varieties to total sward production under typical farm management
Authors: EVANS D. R. , WILLIAMS T. A. , MASON S. A. 
Published: April 2006

AbstractWhite clover varieties, potentially suitable for inclusion in seed mixtures for mixed stock‐rearing farm systems, were evaluated when growing with S23 perennial ryegrass under rotational sheep grazing with a silage cut in late May or early June, as practiced on farms. Monoculture grass swards were also included to enable the direct and indirect contribution of white clover to total sward production to be evaluated.White clover increased total sward production during all three years of the trial by an average of 50%. Although clover content of swards were similar, large differences occurred in their grass content, especially in the third year, when difference in total yields of swards based on large–leaved clover varieties was 2 t ha −1 while difference in clover yield was only 0‐6 to ha–1 The indirect contribution of white clover, namely the extra grass resulting from N transfer, was greater in the spring than in the autumn. It was also greater for Nesta than for other varieties. and exceptional for this variety in that the increase in grass yield above that of grass monoculture was maintained over three harvest years.
A simulation model of the microbiological and chemical changes accompanying the initial stage of aerobic deterioration of silage
Authors: COURTIN M. G. , SPOELSTRA S. F. 
Published: April 2006

AbstractA mathematical model is presented that predicts the time‐course of aerobic deterioration in grass and whole‐crop maize silages. The model predicts the stability of the silage taking into account the buffering capacity of the silage, the initial contents of organic acids and ethanol, pH, the initial temperature and the initial populations of the microorganisms. The specific processes simulated include the growth of yeast and acetic acid bacteria, the oxidation of fermentation products, the consumption of oxygen and the production of carbon dioxide, the rise in temperature. and the increase in pH.The deterioration of silage is seen to be initiated by acetic acid bacteria or by yeast, or by both groups together. The factors that determine which groups will prevail are the dry matter contents and the chemical composition of the silage. The output of the model is validated by comparison of the simulated data with data from published work on the deterioration of silage.
An evaluation of the effects of grazing management systems involving preferential treatment of high‐yielding dairy cows on animal performance and sward utilization
Authors: MAYNE C. S. , CLEMENTS A. J. , WOODCOCK S. C. F. 
Published: April 2006

AbstractTwo systems of grazing management involving preferential treatment of high‐ yielding dairy cows were compared with a grazing system in which both high‐ and low‐yielders received uniform treatment. Cows were rotationally grazed across I‐day paddocks without concentrate supplementation from 23 April to 8 October 1985, with a mean stocking rate over the season of 5‐4 cows ha−1. Preferential treatment of high‐yielding cows was achieved either by using a leader/follower approach (LF) with high‐yielding cows in the leader group, or by preferential forage feeding (PFF) where high‐yielding cows were allowed access to grass silage for 1 ‐5 h daily and grazed alongside low‐yielders. Control (C) cows grazed together as a single group. The high grazing stocking rates used on all three treatments resulted in good grass utilization with residual sward heights, assessed by a rising‐plate sward stick, of 45, 50 and 48 mm for the LF, PFF and C treatments respectively. Animal performance data for the LF, PFF and C treatments respectively were: milk yield (kg d−1) 15middot;1, 15middot;6 and 14middot;7 (s.e. 0middot;78); milk fat yield (g d−1) 598, 606 and 567 (s.e. 34); milk protein yield (g d−1) 500, 519 and 480 (s.e. 31); and live weight gain (kg d−1) 0middot;12, 0middot;23 and 0middot;25 (s.e. 0·05). These results indicate that leader/follower grazing had little overall effect on animal performance when high grazing severity was imposed, with the improvement in animal performance of high‐yielding cows in the leader group being offset by the reduced performance of the follower group. Buffer‐feeding of high‐yielding, rotationally‐grazed cows with high‐quality grass silage had little effect on animal performance and resulted in a decrease in the efficiency of grassland utilization. Silage appeared to substitute for herbage, with a reduction in herbage DM intake of 0middot;55 kg per kg silage DM consumed.
Effect of agrochemical applied at sowing on seedling emergence and herbage yield of perennial ryegrass and white clover
Authors: LEWIS G. C. , COOK R. , van der ENDE A. 
Published: April 2006

AbstractPlots of white clover (Trifolium repens) and perennial ryegrass (Lolium perenne) white clover were sown with and without fungicide seed treatment, seed treatment with Cytozyme (a proprietary growth‐promoting agent) and pesticide granules (carbofuran or carbosulfan) mixed with the seed. Sowings were made in April/May at Hurley (1986 and 1987), Dorchester (1987) and Bronydd Mawr (1987). Only treatments containing pesticide significantly improved seedling emergence or herbage yield in the 1986 sowing. In 1987, pesticide greatly increased seedling emergence of ryegrass and clover at Hurley and Dorchester, but had no effect at Bronydd Mawr. At Hurley, herbage yield and the proportion of clover were more than doubled for up to a year, by chemical treatment after sowing in 1986.Populations of plant parasitic nematodes were recorded at all sites and it is suggested that at Hurley and Dorchester seedlings with nematode damage were unable to survive the dry soil conditions that prevailed. In a subsequent pot experiment, pesticide granules controlled root endoparasitic nematodes and significantly increased seedling emergence of white clover in dry soil but had no effect in moist soil.
Enzymes as silage additives 2. The effect of grass dry matter content on silage quality and performance in sheep
Authors: JACOBS J. L. , COOK J. E. , MCALLAN A. B. 
Published: April 2006

AbstractEight grass silages were made from two contrasting varieties of perennial ryegrass, four silages each from a late‐cut early‐maturing (high dry matter, HDM) variety and from an early‐cut, late‐maturing (low dry matter, LDM) variety. The grass was ensiled without additive (untreated), or with formic acid, or with one of two enzyme mixtures of hemicellulases and cellulases (enzyme 1 and enzyme 2) for a period of 130 d.Formic acid‐treated silage had lower levels of lactic acid at both levels of dry matter than the other silages. Enzyme treatment of grass prior to ensilage resulted in reduced levels of cellulose, acid‐detergent fibre and neutral‐detergent fibre in LDM silages and lower acid‐detergent fibre and neutral‐detergent fibre in the HDM silages compared with the corresponding untreated and formic acid‐treated silages. Voluntary intakes (g DM d−1) of untreated and enzyme‐treated silages were significantly (P<0·01) lower at both digestibilities compared with formic acid‐treated silages (LDM: untreated, 982; formic, 1069; enzyme 1, 868; enzyme 2, 937; HDM: untreated, 931; formic, 1027; enzyme 1, 943; enzyme 2, 914). The organic matter, carbohydrate and nitrogen digestibility coefficients of LDM silages were significantly (P<0·001) higher than those of HDM silages. There were no significant differences in any component digestibility related to silage additive.Comparison of digestibility coefficients for constituents of the LDM silages fed to sheep or steers showed no differences between species.
A new descriptive scale for early reproductive development in Lolium perenne L.
Authors: SWEET N. , WILTSHIRE J.J.J. , BAKER C.K. 
Published: April 2006

AbstractEarly reproductive development in Lolium perenne L. has been widely used for defining growth stages in spring, and this has been useful in managing seed crops and in trials involving the use of growth retardants.A numerical scale for apical development based on morphological criteria, has been successfully used in research. The scale identifies eleven clearly recognizable stages of apical development, from the vegetative apex through to the immature, but completely‐formed spike. It is intended that the key should be used to identify consistantly precise stages in apical development.
Relationship between climatic factors and the dry matter production of swards of different composition at two altitudes
Authors: MENZI H. , BLUM H. , NÖSBERGER J. 
Published: April 2006

AbstractThe growth of a timothy sward, a timothy/white clover mixture and a multi‐grass/white clover mixture were compared and related to climatic factors at two sites of different altitudes.Temperature and radiation had a greater effect on sward growth than did species composition or management. If the reproductive and vegetative growth periods were studied separately, then more than 90% of the variation in yield could be explained by temperature and radiation. During spring reproductive growth, yields per unit increment of temperature or radiation were 2–3 times higher than during summer vegetative growth. Spring growth was affected more by temperature than by radiation and the lower yields at the higher altitude were also related to lower temperatures.
Spatial heterogeneity and other sources of variance in sward height as measured by the sonic and HFRO sward sticks
Authors: HUTCHINGS N. J. 
Published: April 2006

AbstractMeasurements of undisturbed sward surface height (sward height) were made using the HFRO and sonic sward sticks at 20 cm intervals along 100 m transects laid across paddocks grazed by either sheep, cattle or goats. Measurements of sward height were also made at 5 cm intervals along 10 m transects laid across the same paddocks using the HFRO sward stick alone. The variance of the measurements from each transect was partitioned across the range of spatial scales of roughness present using spectral analysis. The variance of the sward surface height appeared to be dominated by variation with spatial scales of less than 1 to 2 m. The variances of measurements made with the two sward sticks were similar despite the greater sampling area of the sonic sward stick. This was due to the presence of variation at spatial scales much larger than the sampling area of either instrument and to a greater contribution from non‐spatially related sources to the variance of the sonic sward stick measurements. The use of weighted disc meters for obtaining the mean height of continuously grazed sward deserves re‐examination, while automation of the sonic sward stick may be worthwhile if the spatial distribution of herbage is to be described.
Influence of bacterial inoculant and substrate addition to lucerne ensiled at different dry matter contents
Authors: JONES B. A. , SATTER L. D. , MUCK R. E. 
Published: April 2006

AbstractField‐wilted lucerne was chopped with a forage harvester at 33 ± 1·5, 43 ± 2·0 and 54 ± 1·8% dry matter, treated and ensiled in laboratory silos during four cuttings in each of two years. Treatments were control (C), sugar addition at 2% of fresh weight (S), inoculum applied at 3 × 105 bacteria g−1 herbage (I), and sugar and inoculum combined (IS). Duplicate silos were opened and analysed after 1, 2, 3, (4 or 5), 7, 14 and 60 d of fermentation. The initial rate of proteolysis of lucerne protein decreased with increasing dry matter (DM) content of the lucerne, and was not influenced by the year, cutting or silage treatment. Inoculation increased (P<0·05) the rate of pH decline for all silage dry matters, and shortened the lag time prior to pH decline with 33 and 43% dry matter silages. Sugar addition had no effect on rate of pH decline or lag time. Inoculation and sugar addition both lowered final pH, acetic acid, ammonia (NH3), free amino acids (FAA) and soluble non‐protein N (NPN) in silages (P<0·01) and increased lactic acid content with 33 and 43% dry matter silages. Only inoculation was beneficial at 54% DM with no difference between I and IS. The influence of forage characteristics (epiphytic lactic acid bacteria, buffer capacity and sugar:buffer capacity ratio) on treatment effectiveness varied with dry matter content.
Reseeding in the Falkland Islands. Herbage production of a range of grass species and cultivars
Authors: DAVIES T.H. , RILEY JANET 
Published: April 2006

AbstractThe productivity of 20 cultivars from a range of 13 grass species was compared by harvesting four times during each of three successive growing seasons. In the experiment, 120 kg N ha−1, 42 kg P2O5 ha−1 and 42 kg K2O ha−1 were applied annually.Mean annual yield was 3229 kg DM ha−1 and 2147 kg DOM ha−1. Cultivars were arranged in seven groups for comparison. Three of the groups, Lolium, Phleum and ‘others’ (the latter consisted of Festuca arundinacea cv. Dovey and Poa pratensis cv. Bensun A.34) appeared significantly lower yielding than the Dactylis, Festuca (fine‐leaved), Agrostis and Holcus groups.In the Lolium group, cv. Gremie outyielded cv. Melle every year. No cultivar of Dactylis was significantly better than any other in its group. Phleum CVS Motim and Eskimo were similar and superior to cv. S.50. Festuca ovina cv. Novina and Agrostis canina cv. Kingstown were marginally the best in their respective groups. The two cultivars of Holcus performed virtually identically. Festuca arundinacea cv. Dovey was a good producer of early spring grass. Poa pratensis cv. Bensun A.34 was generally low yielding and subject to fungal rust attack in autumn. The pattern of seasonal DM production was 16% in early spring (cut in October/November), 39% in mid‐season (cut in December), 40% in late summer (cut in February/March) and 5% in autumn (cut in April/May). Quality of the herbage was superior to the main indigenous grass Cortaderia pilosa.It was concluded that although the experiment was conducted under a cutting regime it provided useful guidance for seeds mixture formulation and stock carrying capacity calculations.
The comparative performance of Holcus lanatus and Lolium perenne under sheep grazing in the Scottish uplands
Authors: MORTON J. D. , BOLTON G. R. , HODGSON J. 
Published: April 2006

AbstractAn experiment was conducted over 3 years (1983‐85) to assess the performance of Holcus lanatus German Commercial and cv. Massey Basyn compared with Lolium perenne cv. Perma on a gley soil under sheep grazing in the Scottish uplands. All grasses were sown together with Trifolium repens cv. Grasslands Huia. The swards were rotationally grazed at similar herbage allowances. During the first harvest year, the swards were grazed hard to a low mass (500 kg DM ha−1). In the second harvest year, post‐grazing herbage masses of 500 and 1000 kg DM ha−1 were compared.Perma ryegrass had a higher level of herbage production than both H. lanatus cultivars in the first and second harvest years after sowing and hence had a greater number of sheep grazing days. The ryegrass sward consisted of 25% more green sown grass (85 cf. 60%) but 12% less white clover (4 cf. 16%) compared with both H. lanatus cultivars in the establishment and first harvest years. The persistence of all three grasses was poor although ryegrass had a higher presence (36%) than either Massey Basyn (22%) or German Commercial (13%) at the end of the. second harvest year.At a similar herbage allowance, there were no significant differences in the herbage intake and liveweight gain of sheep. Ryegrass had a higher organic matter digestibility and lower neutral and acid detergent fibre and lignin contents than either of the H. lanatus cultivars.In the second harvest year, although herbage production was greater at the higher herbage mass, there was no difference in the proportion of sown grass.It was concluded that ryegrass is a superior grass to H. lanatus on upland soils with high N status, moderate P status and a high pH.
The effects of poloxalene on ingestion by cattle grazing Lucerne†
Authors: DOUGHERTY C. T. , COLLINS M. , BRADLEY N. W. , LAURIAULT L. M. , CORNELIUS P. L. 
Published: April 2006

AbstractThe mechanisms that terminate meals of cattle grazing lucerne (Medicago sativa L.) are not well defined. Sub‐acute bloat may lead to cessation of grazing and, consequently, surface active substances used in the treatment and prevention of bloat, such as poloxalene, may extend grazing meals and increase herbage intake. Twelve mature Angus cows (Bos taurus) were offered 0, 12·5 and 25·0 g poloxalene in 0·5 kg of crushed maize (Zea mays L.) kernels each day, immediately before two consecutive 1‐h measured parts of a grazing meal on 21‐ to 24‐day‐old lucerne swards with a herbage dry matter (DM) mass (> 5 cm) of 2·03 t ha−1 and herbage DM mass allowance of 3·55 kg hd−1h−1. Total herbage DM intake was 2·52 kg hd−1 during the first hour and 1·54 kg hd−1 during the second hour of the 2‐h grazing meal. Differences in herbage intake were attributable to a cessation of grazing. Mean rates of biting were 26·3 and 14·8 bites min−1 and mean DM intakes per bite were 1·82 and 4·38 g during the first and second part of meals, respectively. Poloxalene treatments caused a small linear decline in grazing time during the first part of meals and a larger increase in grazing time during the second part of meals. Lower rates of DM intake caused by poloxalene were offset by increases in grazing time. It was concluded that poloxalene moderated ingestive behaviour within grazing meals of immature lucerne and this response may have been at least partly due to the relief of sub‐acute bloat.
Animal production evaluation of herbage varieties. 1. Comparison of Aurora with Frances, Talbot and Melle perennial ryegrasses when grown alone and with clover
Authors: MUNRO J. M. M. , DAVIES D. A. , EVANS W. B. , SCURLOCK R. V. 
Published: April 2006

AbstractComparative herbage characteristics and sheep production (ewes and lambs until weaning and lambs thereafter) from swards of Aurora (very early flowering), Frances (early flowering), Talbot (intermediate flowering) and Melle (late flowering) varieties of perennial ryegrass (Lolium perenne) were studied under a continuous variable stocking management based on sward surface height guidelines. The varieties were assessed as grass‐only (215 kg N ha−1 fertilizer) and grass/clover (83 kg N ha−1 fertilizer) pastures.Over 2 years (1985‐86) total annual lamb production per hectare from grass‐only swards of Aurora was 19% more than that from Frances despite similar herbage productivity. Differences between the varieties in lamb output were more pronounced as grass/clover swards, with Aurora producing 29 and 18% more lamb than Melle and Talbot respectively and with Frances also giving 16% more than Melle. Overall lamb production from grass/clover swards was 10% more than that from the grass‐only pastures, mainly due to 69% advantage in individual lamb growth rates after weaning. Herbage organic matter digestibility, during the post‐weaning period, was higher on grass/clover than on grass‐only swards, and similarly with Aurora versus the other varieties. Under a frequent cut simulated grazing regime the relative herbage productivity of the four varieties differed, with Aurora 13% less productive than Frances.The results are discussed in relation to the limitations of assessing performance under cutting, and the significance of the interaction in animal productivity between the two sward types.
The effect of row spacing and cover‐crop on stolon development and the seed yield components of white clover cultivars of contrasting leaf size
Authors: HOLLINGTON P. A. , MARSHALL A. H. , HIDES D. H. 
Published: April 2006

AbstractThree white clover cultivars, S184 (small‐leaved), Menna (medium‐leaved) and Olwen (large‐leaved), were broadcast or sown in 15, 30 or 60 cm drills at a seed rate of 3 kg ha‐1. The three cultivars were either sown without a cover‐crop or sown under a cover‐crop of spring barley (cv. Crescent) or peas (cv. Countess). The effects of these methods of establishment on the stolon growth and components of seed yield were subsequently measured.Stolon growth and development was influenced by row spacing, cultivar and season. The overall plant response at all but the widest row spacing (60 cm) was to increase stolon growth such that inflorescence production, the number and proportion of ripe inflorescences and the other seed yield components were unaffected by row spacing. Cultivars differed in their response to row spacing. Cultivar Olwen produced most inflorescences and more ripe inflorescences when broadcast, cv. S184 when sown at 60 cm row spacing and cv. Menna at 15 or 30 cm row spacing. Cultivars also differed in their response to cover‐crop, with cvs Menna and S184 producing more inflorescences and more ripe inflorescences when sown under barley and peas than when pure sown. The inflorescence production of cv. Olwen was not influenced by cover‐crop.The relationship between vegetative and reproductive growth is discussed in relation to establishment, cultivar and climate and the possible implications for the establishment of white clover seed crops in the UK.
A comparison of formic acid and an acid‐salt type additive on the performance of dairy cows in early lactation
Authors: DAVIES O. D. , HAIGH P. M. 
Published: April 2006

AbstractPerennial ryegrass, harvested as second‐cut material on 10 and 11 July 1990, was treated with either formic acid at 31 t‐1 or an acid‐salt type additive at 61 t‐1 and ensiled in roofed 150 t bunker silos. Subsequently both silages underwent a predominantly lactic fermentation. Nevertheless the acid‐salt‐treated silage had a significantly higher quantity of formic acid (19 vs 12 g kg DM‐1) and significantly lower levels of lactic (98 vs 118 g kg DM‐1) and acetic acid (11 vs 17 g kg DM‐1) compared with formic acid‐treated silage. In‐silo losses and effluent production were similar.Each silage was individually fed to 10 October‐calving Friesian dairy cows (average weight 565 kg) from weeks 2 to 15 of lactation, together with 3 kg d‐1 of a compound feed containing 190 g kg DM‐1 crude protein and with an estimated metabolizable energy content of 12·6 MJ kg DM‐1. The acid‐salt additive had no significant effect on silage DM intake, daily milk yield, milk protein or cow liveweight change, but significantly increased milk butterfat content compared with formic acid‐treated silage.It is concluded that the acid‐salt type additive produced little difference in terms of either silage fermentation or animal performance compared with formic add treatment.