bluuebunny/crossref_metadata_2025_split huggingface dataset:
The reduction of frit fly oviposition on seedling ryegrass by the presence of oats
Authors: MOWAT D. J. , JESS S. 
Published: April 2006

AbstractSeedling ryegrass and oat plants in various proportions were exposed to oviposition by frit fly in the laboratory. The growth stage of the ryegrass ranged from single‐leaved (unattractive as oviposition sites) to three‐leaved (almost immune to serious damage). Oat plants attracted most oviposition and their inclusion usually reduced oviposition on ryegrass, by up to 90%. Where the frit fly population density was so high that potential oviposition exceeded the availability of oviposition sites, inclusion of oats did not reduce the number of eggs laid on ryegrass.This approach does not, therefore, show promise of a reliable control method against severe primary attack in the field, but is potentially useful over an important range of population densities at which further control measures might otherwise be required. The inclusion of oats would also provide an early warning of damage.
Growth performance, appetite and plasma ammonia concentrations in heifers fed inoculated lucerne prior to ensilage, then supplemented with sodium bicarbonate
Authors: PHILLIP L. E. , UNDERHILL L. , GARINO H. 
Published: April 2006

AbstractA study was conducted to explore the possibility of a synergistic effect of an inoculum of lactic acid bacteria and sodium bicarbonate in improving the nutritive value of lucerne silage. Twenty Holstein heifers (live weight 183 ± 9·4 kg) were assigned to four dietary treatments consisting of: lucerne uninoculated or inoculated prior to ensilage and then either unsupplemented or supplemented with NaHCO3 (40 g kg−1 dry matter (DM)). The lucerne silage contained 320 g kg−1 DM and constituted 600 kg−1 diet DM. The animals were fed once daily for 90 d and samples of jugular blood were analysed for plasma ammonia and indices of blood acid‐base status. Inoculation of Lucerne reduced (P<0·01) silage pH but had no other effect on silage composition. In the absence of NaHCO3, liveweight gain and organic matter intake were improved by inoculating lucerne prior to ensilage; however, in the presence of NaHCO3, inoculation reduced growth rate but had no major effect on intake. Dietary treatment did not (P>0·05) affect the concentration of plasma ammonia or measures bf blood acid‐base status. The results suggest that NaHCO3 may have nullifled any potential benefit of inoculating lucerne silage to improve its nutritive value for heifers.
Decision rules for controlling the sward height of continuously grazed experimental pastures
Authors: HUTCHINGS N. J. , BOLTON G. R. , BARTHRAM G. T. 
Published: April 2006

AbstractTwo contrasting decision rules for adjusting stock density to control the sward height of continuously grazed grass swards were tested and developed. One rule calculated the adjustment as a percentage of the existing stock density (Percentage Rule); the other related the adjustment to estimates of the bulk density of the grazed horizon and individual animal intake (Absolute Rule). Both decision rules related the adjustments to the change in sward height over the previous week and to the deviation from the target value. The decision rules were tested by continuously grazing lactating ewes and then dry ewes after weaning with a target sward height of 4 cm on 0·33‐ha plots with stock density adjusted by varying animal numbers. The Percentage Rule failed to increase the stock density sufficiently rapidly when grass growth was accelerating, leading to increasing deviation in sward height from a 4 cm target value. The Absolute Rule succeeded in controlling sward height once the bulk density term had been correctly adjusted. Pre‐emptive adjustment of stock density in anticipation of a change in grass growth rate marginally improved the control that was achieved by the Absolute Rule.
Effects of sward height and bulk density on bite dimensions of cattle grazing homogeneous swards
Authors: LACA E. A. , UNGAR E. D. , SELIGMAN N. , DEMMENT M. W. 
Published: April 2006

AbstractEffects of sward height and density on the dimensions and weights of bites taken by cattle were examined. In one experiment, swards of dallisgrass lamina were constructed by hand in a factorial combination of four heights (80, 150, 180 and 300 mm) and three densities (c. 700, 1500 and 2700 g m−3). In the other, swards of lucerne were constructed in a factorial combination of three heights (70, 150 and 250 mm) and three densities (1500, 2800 and 5900 g m−3). Treatments were replicated on three steers of 750 kg average weight. The first six bites taken from the sward were monitored, and functional relationships between sward characteristics and bite dimensions derived. Results from both experiments were similar. Average bite area was not constant as often assumed, but decreased linearly with density and increased quadratically with height, with slope negatively affected by density and height. In tail swards, bite area reached a plateau of c. 170 cm2, determined by the sweep of the tongue. In contrast with the widely used model, bite depth increased linearly with height, with slope negatively affected by density. Response of bite dimensions was explained by the mechanics of the interaction between tongue and jaw movements, and sward structure. Bite weight varied less than bite dimensions, because of compensatory effects between bite area, bite depth and density. Animals obtained heavier bites in tall sparse swards than on short dense ones of equal mass/area. Even in homogeneous swards, both density and height are necessary to predict bite weight.
Allowance‐intake relations of cattle grazing vegetative tall fescue†
Authors: DOUGHERTY C. T. , BRADLEY N. W. , LAURIAULT L. M. , ARIAS J. E. , CORNELIUS P. L. 
Published: April 2006

AbstractHerbage allowance is one of the important pasture factors in the determination of intake by grazing livestock. Ingestive behaviour of 12 adult Angus cows (Bos taurus) was measured over a range of allowances (0·25 to 0·72 kg dry matter (DM) per 100 kg live weight (LW) for a 1‐h period) of vegetative tall fescue (Festuca arundinacea Schreb.). A balanced change‐over design was used to estimate direct, residual and permanent effects of herbage allowance on rate of DM intake, rate of biting and herbage DM intake per bite. In Experiment 1, herbage DM intake per meal increased linearly from 0·68 to 1·72 kg (100 kg LW)−1 as DM allowance increased from 0·25 to 0·72 kg (100 kg LW)−1 h−1. Cows grazed at ·30 kg (100 kg LW)−1 h−1 and stopped grazing when the sward was reduced to a height about 10 to 12 cm above the soil surface, approximately defined by the tops of pseudostems. In Experiment 2, herbage DM intake rates of 0·29, 0·47 and 0·42 kg (100 kg LW)−1 h−1 were recorded as cows grazed allowances of 0·43, 0·70 and 0·90 kg (100 kg LW)−1 h−1 for most of the 1‐h grazing period. Limiting herbage DM allowances in Experiment 2 were associated with small reductions in rate of biting and herbage DM intake per bite as allowance declined. Sward DM density (>5 cm) was an important variable in the determination of herbage DM intake rates at lower herbage allowances.
The performance of beef cattle given silages made from perennial ryegrasses of different maturity groups, cut on different dates
Authors: STEEN R. W. J. 
Published: April 2006

AbstractTwo experiments were carried out to examine the interaction between early and late‐heading varieties of ryegrass and date of harvesting of primary growths for silage in terms of the performance of beef cattle. A sward containing equal proportions of three early heading varieties (Cropper, Premo and Frances) (50% ear‐emergence on 18 May) was harvested on 20 May (T1), 28/29 May (T2) and 5/6 June (T3) and a sward containing three late‐heading varieties (Perma, Preference and Parcour) (50% ear‐emergence on 12 June) was harvested on 28/29 May (T4), 5/6 June (T5) and 12/14 June (T6) in 1985 and 1987. In each year the six silages were harvested without wilting and were ensiled in trench silos. In Experiment 1 they were offered ad libitum and unsupplemented to 48 steers (407 kg live weight (LW)) for 101 days and in Experiment 2 they were offered with 2 kg concentrates per head daily to 48 heifers (392 kg LW) for 105 days. In Experiment 1 in vivo digestible organic matter (DOMD) concentrations in dry matter were 717, 671, 643, 709, 672 and 640 (s.e. 8·4) g (kg DM)−1; silage DM intakes 7·1, 6·6, 6·6, 7·2, 7·3 and 6·7 (s.e. 0·15) kg d−1; LW gains 0·94, 0·74, 0·62, 0·90, 0·82 and 0·57 (s.e. 0·047) kg d−1; for T1 to T6 respectively. For Experiment 2, DOMD concentrations were 732, 699, 636, 734, 686 and 663 (s.e. 9·6) g (kg DM)−1; silage DM intakes 6·4, 5·7, 6·0, 6·0, 5·5 and 5·0 (s.e. 0·22) kg d−1; LW gains 1·12, 0·92, 0·99, 1·14, 0·88 and 0·76 (s.e. 0·078) kg d d−1; and carcass gains 0·66, 0·56, 0·51, 0·68, 0·55 and 0·48 (s.e. 0·048) kg d d−1; for TI to T6. It is concluded that silages made from early and late‐maturing swards of perennial ryegrass sustained similar levels of performance in beef cattle when they were harvested at equal digestibility, and the digestibility declined at similar rates for the two sward types when harvesting of the primary growths was delayed. Under the conditions of these experiments the same level of animal performance was sustained by silages made from the two swards when the late‐maturing varieties were harvested 7 days after the early varieties. This compares with an interval of 25 days between the early and late‐maturing varieties reaching 50% ear‐emergence.
Cell wall degrading enzymes for silage. 2. Aerobic stability of enzyme‐treated laboratory silages
Authors: SELMER‐OLSEN I. , HENDERSON A. R. , ROBERTSON S. , McGINN R. 
Published: April 2006

AbstractThe effects of two commercial cellulase/hemicellulase enzymes derived from Trichoderma reesei on silage fermentation and aerobic stability were investigated in three laboratory‐scale experiments. In Experiment 1, perennial ryegrass (Lolium perenne) was treated with enzyme A at the rates of 0. 0·125, 0·250, 0·500 and 0·750 cm3 kg‐1. In Experiment 2, Italian ryegrass (Lolium multiflorum) was treated with the same enzyme at the rates of 0, 0·250 and 0·500 cm3 kg‐1 and with 85% formic acid (3·5 cm3 kg‐1). In Experiment 3, perennial ryegrass was ensiled untreated, with enzyme A (0·250 and 0·500 cm3 kg‐1) and with 0·200 and 0·400 cm3 kg‐1 enzyme B which also contained glucose oxidase. All silages were well preserved. Aerobic deterioration was related to numbers of lactate assimilating yeasts. In Experiment 1, all silages were stable over a 4‐day period. In Experiment 2, enzyme A treatment delayed the temperature rise compared with the untreated control (P<0·05), whereas the formic acid‐treated silage was stable. In Experiment 3, the temperature rise in the silage treated with the higher level of enzyme B occurred one day later than in the other silages (P<0·05).
Management options for increasing white clover contents of swards, without resowing
Authors: SHELDRICK R. D. , LAVENDER R. H. , MARTYN T. M. 
Published: April 2006

AbstractTwo field experiments were carried out at North Wyke, Devon in 1985 (Experiment A) and 1986 (Experiment B) to investigate the effectiveness of either cutting or rotational sheep‐grazing managements for raising the clover content of clover‐depleted swards. Subplots were pretreated in March with (a) propyzamide at 0·4kg a.i. ha‐1, (b) chlorpyrifos at 0·72 kg a.i. ha‐1 and methiocarb at 0·22 kg a.i. ha‐1, (c) carbofuran at 1·3 kg a.i. ha‐1, or (d) not so treated, in order to reduce grass tiller density, control insect and mollusk pests, or control all invertebrate pests respectively (a‐c), Carbofuran was not applied to swards that were to be grazed subsequently. The propyzamide pretreatment (a) significantly reduced the quantity of herbage dry matter (DM) grazed and the silage DM yields in both years, but raised the numbers of active clover buds, and clover stolon density and its weight in 1986, though not in 1985, The pesticide package (b) raised the quantity of herbage DM grazed in both years, and the silage DM yield in 1986, Carbofuran (c) raised silage yields in 1985. Neither pretreatment (b) nor (c) significantly affected clover performance. In comparison with sheep grazing, cutting showed a trend to higher DM yields, and significantly raised clover stolon density and weight in both years, and active bud numbers in 1986. The periodic sheep grazing management included recovery intervals of 14 d and 35 d. In 1986 (but not 1985) the longer recovery interval raised herbage DM consumption, but had no effect on clover development. The cutting management included nitrogen inputs of either 100 kg ha‐1 in March, or none. N input raised annual DM yields in 1986 (but not 1985) but did not affect clover DM yields or performance in either year.The experiments at North Wyke were supported by on‐farm experiments using exclosure cages at ten sites in 1985 and nine in 1986, in Yorkshire, Wales, the Midlands and Devon. In both years, application of propyzamide as in treatment (a) reduced DM yields (P<0.001) and raised the proportion of clover (P<0.001) in May harvests. The density of active clover buds (P<0.05), stolon density (P<0.001) and stolon weight (P<0.001) were increased by October. A combined carbofuran and methiocarb treatment significantly (P<0.001) increased herbage yields, but did not affect measures of clover performance. Unlike the main experiments, a comparison of grazing (outside the cages) and cutting management (within the cages) showed no effect on clover development.It was concluded that cutting, or rotational sheep grazing with a long recovery interval, would promote clover development in the clover depleted sward. Though successful in the overall assessment, application of propyzamide gave highly variable results on different sites and was not sufficiently reliable.
Sodium fertilizer application to pasture. 4. Effects on mineral uptake and the sodium and potassium status of steers
Authors: CHIY P. C. , PHILLIPS C. J. C. 
Published: April 2006

AbstractMineral availability and status in body tissues was examined with four rumen‐fistulated steers arranged in a Latin‐square change‐over design. The steers were fed perennial ryegrass herbage from a pasture fertilized with four Na treatments: 0 (Nil), 32 (Low), 66 (Medium) or 96 (High) kg Na ha‐1 yr‐1. Na fertilizer increased herbage contents and intakes of Na, Mg and Ca but did not affect intakes of K, P and S. Herbage K:Na and K:(Ca+Mg) decreased in direct proportion to the amount of Na fertilizer applied. With increasing dietary Na intake, the Na content of saliva increased and the K content decreased. There was an increase in Na and a reciprocal decrease in K contents of rumen fluid with increasing dietary Na. Blood plasma Na contents were greater when the Na‐treated herbages were fed than in the Nil treatment. There was no effect of treatment on blood plasma K content. Increasing dietary Na increased urinary Na but did not affect urinary K. Faecal mineral concentrations of Na, Ca, P and S were increased by increasing dietary Na, whereas K content was reduced and the Mg content was unaffected. There was no difference between treatments in the proportion of mineral rapidly solubilized, except Na which increased with increasing dietary Na content. The fractional rate of degradation was greater for Na, K, and Mg than for Ca and P. Based on effective solubilization, minerals were ranked in the order K > (Mg = Na) > Ca > P, and treatments were in the order Medium > (High = Low) > Nil. Increasing Na intake increased Ca but not P or Mg availability and increased the uptake of all three minerals.
Spring defoliation of white clover seed crops. 1. Inflorescence production of contrasting white clover cultivars
Authors: MARSHALL A. H. , HOLLINGTON P. A. , HIDES D. H. 
Published: April 2006

AbstractThree white clover cultivars, S184 (small‐leaved), Menna (medium‐leaved) and Olwen (large‐leaved), were sown at a seed rate of 3 kg ha‐1 under spring wheat cv. Tonic. In the spring of the two following years, there were three pre‐bud emergence mechanical defoliation treatments on which were superimposed four post‐bud emergence treatments giving a total of twelve cutting treatments. Pre‐bud emergence, plots were either cut twice (at approximately two weeks before bud emergence and at bud emergence), cut once at bud emergence or not cut. To each treatment were applied four post‐bud emergence treatments: plots were not cut or cut once (one, two or three weeks after bud emergence). Counts of the total number of inflorescences and of the proportions in various ripeness categories were made throughout the period of seed crop development to determine the pattern of inflorescence development and optimum harvest date. Overall, inflorescence numbers were greatest in cv. S184and least in cv. Olwen. Defoliation before bud emergence had no effect on inflorescence production; however, it was significantly influenced by defoliation after bud emergence. Although delaying the initial development of the crop, inflorescence numbers of all cultivars were highest in both years following cuts two and three weeks after bud emergence. Optimum harvest date was not affected by defoliation or cultivar, numbers of ripe inflorescences in both years reaching a peak at the end of August. The number of brown inflorescences, which may also contribute to seed yield, reached a peak in both years in late July. Seasonal differences in inflorescence production were again observed, emphasizing the difference between first and second year crops and importance of climate in while clover seed production. The implications of these differences in numbers and proportions of inflorescences in various ripeness categories under different defoliation regimes are discussed in relation to seed crop management in the UK.
Calibration of two techniques for estimating herbage mass
Authors: GABRIËLS P. C. J. , VAN DEN BERG J. V. 
Published: April 2006

AbstractTwo non‐destructive techniques for estimating herbage mass (dry matter yield) were evaluated during the growing season of 1988, from April to September. Samples were collected from four sites, with ten observations made on twenty‐five days at each site, giving a total of 612 sample units. Observations were obtained from each unit, either with a plastic rising‐plate meter (335) or with a metal rising‐plate meter (227). In addition, measurements with a single‐probe capacitance meter (Pasture Probe) were also made on all units. The usefulness of the non‐destructive methods for predicting the actual yield was evaluated by calibrating them by means of regression on the yield determined by mowing 1·5‐m2 quadrats, weighing, subsampling and drying the grass. The yield measurements were logarithmically transformed to correct for the proportionality of the residual variance with the mowed dry matter yield. Logarithmic transformation of the sensor measurements improved the linearity of the calibration relationships. The combination of one rising‐plate meter and the Pasture Probe resulted in a linear and additive model with a larger adjusted R2 than models with just one of these two sensors. The addition of the predictors ‘external moisture’ (e.g. dew), ‘day number after mowing’ and ‘site number’ significantly increased the goodness of fit of many models. In some models addition of the logarithm of the ‘dry matter percentage’ was significant. Other predictors in these models such as “Julian day number” and “grazing” proved not to be significant. The adjusted R2s in the best models for the metal and the plastic discs were 89·7% and 87·3% respectively. The corresponding coefficients of variation were 26·2% and 26·1%.The results show that further research is necessary to refine the techniques or to develop new techniques to estimate the dry matter yield, before the sensors can be usefully integrated into a management system.
The effect of the weather on the drying rate of cut diploid and tetraploid perennial ryegrass (Lolium perenne L.) and diploid hybrid ryegrass (Lolium perenne×L. multiflorum)
Authors: ATZEMA A. J. 
Published: April 2006

AbstractThe drying rate of cut diploid and tetraploid perennial ryegrasses (Lolium perenne L.) and a diploid hybrid ryegrass (Lolium perenne×L. multiflorum), and associated meteorological characteristics, were studied in the field for three successive years: 1988, 1989 and 1990. Meteorological elements measured were: air temperature (at 0·1 in and 1·5 in height), dew point temperature (at 1·5m height), temperature within the grass sward, grass surface temperature, global radiation and wind speed (at 2 in height).Apart from the weather, the drying depended on the grass species and the yield. Hybrid ryegrass had a lower initial moisture content at cutting in the morning than perennial ryegrass. Also, the hybrid ryegrass dried faster than the perennial ryegrass. Within the same varieties a low yield dried faster than a high yield. Frequent tedding did not influence the rate of drying. The temperature within the grass swath approached the air temperature at 1·5 m. The grass surface temperature was greatly affected by global radiation. Increasing wind speed had an adverse effect on the drying rate of grass.
White clover contribution to continuously stocked sheep pastures in association with contrasting perennial ryegrasses
Authors: FOTHERGILL M. , DAVIES D. A. 
Published: April 2006

AbstractWhite clover content and herbage production in grass/clover swards were studied at contrasting altitudes in Wales. The lowland experiment (1) compared the performance of three clover varieties grown with four diploid perennial ryegrass (Lolium perenne) varieties with a range of heading dates. In the upland experiment (2) the productivity and persistence of Aberystwyth S184 (small‐leaved) clover was studied in association with three perennial ryegrasses.In experiment I. clover content and dry matter production with Aurora (very early) ryegrass was superior to that with Frances (early), Talbot (intermediate) and Melle (late). Furthermore, the performance of Kent wild white clover (small‐leaved) was better than that of medium‐leaved Menna and Grasslands Huia. Averaged over two years (1985 and 1986) mean clover content of Kent was 22% compared with 9% and 10% of Menna and Huia.Performance of S184 clover during the five years (1986–90) of experiment 2 was better with Meltra (late tetraploid) than with Aberystwyth S23 (late diploid) and intermediate with Aurora. Clover stolon length and growing point number declined to a low level in 1988 but increased dramatically in 1989 and 1990 after cessation of applying fertilizer N.Results from both sites were related to animal performance data previously published. It is concluded that small‐leaved clover varieties are needed to ensure a high proportion of clover in sheep pastures and also that choice of companion ryegrass can have a significant effect on the performance of the legume component.