bluuebunny/crossref_metadata_2025_split huggingface dataset:
Herbage growth, white clover content and lamb production on grazed ryegrass‐white clover swards
Authors: MARSH R. , LAIDLAW A. S. 
Published: April 2006

AbstractTwo contrasting Gremie perennial ryegrass and Blanca white clover seeds mixtures were established. Each sward type was either continuously or rotationally (four paddocks) grazed at two stocking rates by lambs of 26–28 kg initial mean live weight in two 12‐week experiments. Dry matter production, assessed by the cage method, was lower on the high‐clover sward during the first experiment but overall was similar between seeds mixtures. Clover content, and differences between sward types, declined with time and was lowered by continuous grazing in both experiments and by the higher stocking rate in the first experiment.Animal performance was related to intake and both were increased by lowering stocking rate, increasing clover content and adopting a continuous grazing system. The results are discussed in relation to the experimental methods used and to other published findings.
Nitrogen and Italian ryegrass.
Authors: WILMAN D. , DALY M. 
Published: April 2006

AbstractThe regrowth of Italian ryegrass was studied at weekly intervals from 2 to 14 weeks after a cut in late April when 140 kg ha‐1 N was applied. Reduction in digestibility with delay in date of harvest was due to both an increase in the proportion of cell wall and a reduction in the digestibility of the cell wall, particularly the former from week 2 to about week 5 and particularly the latter after week 5. The reduction in the digestibility of the cell wall was about equally attributable to reduction in digestibility of cellulose and to reduction in digestibility of hemicellulose. The proportion of lignin in cell wall was highly correlated with both digestibility of cellulose and digestibility of hemicellulose. The proportion of digestible cell wall in dry matter was not as constant as has sometimes been noted, increasing by about 5 percentage units from week 2 to week 5 and decreasing by about 10 percentage units from week 5 to week 13. During the latter period the decline in digestible cell wall in dry matter accounted for nearly half the decline in true digestibility of dry matter. The ratio of cellulose:hemicellulose averaged 1:0.89 and hemicellulose was more digestible than cellulose. Rate of increase in yield of cell contents appeared to diminish from about the third week of regrowth onwards, whereas the rate of increase in yield of dry matter did not begin to diminish until about the seventh week. In vitro dry matter digestibility was not increased by adding extra N to the digestion tubes, even with samples containing only 1% N in dry matter.
Water, mineral and energy fluctuations in decomposing cattle dung pats
Authors: UNDERHAY V. H. S. , DICKINSON C. H. 
Published: April 2006

AbstractMoisture and mineral concentrations and calorific values of cattle dung pats were studied under field conditions. The rate of moisture loss from dung pats varied according to the season but the dung was rarely re‐wetted by rainfall. Soluble mineral ions were only leached from pats by prolonged rainfall. Magnesium was particularly resistant to leaching. In the summer months about 15% of the organic matter in the dung was lost over 2 months. The calorific value of the dung decreased by 18% in the same period. The loss of organic matter resulted in a concentration effect in calcium, iron, magnesium and nitrogen.
Pre‐harvest desiccation of crops for conservation. 1. Effect of steam and formic acid on the moisture concentration of lucerne, ryegrass and tall fescue before and after cutting
Authors: TETLOW R. M. , FENLON J. S. 
Published: April 2006

AbstractFive experiments were conducted to determine the effect of pre‐harvest treatment with steam or formic acid on the moisture concentration (MC) in crops of lucerne, two varieties of perennial ryegrass, tall fescue and Italian ryegrass. In each experiment, plots were treated with a mixture of hot gases and steam (S) or sprayed with an aqueous solution of formic acid (F). In the tall fescue experiment the F treatment was applied to the cut swath but in all other instances the F and S treatments were applied to the swards before cutting and the MC changes after treatment compared with those in untreated cut swaths (W 1). Twenty‐four hours after initial treatment all S plots, and those F plots other than tall fescue, were cut and the subsequent water loss compared with that from (i) untreated material cut at the same time (W 2) and (ii) the W 1 plots cut the previous day.In all five experiments the change in the MC of the S plots was similar to that of the W 1 plots both before and after cutting. The reduction in the MC of the F plots before cutting was less than that of the S and W 1 plots, and in three of the five experiments water loss from cut F plots was apparently restricted in comparison with that from untreated cut material (W2).Neither desiccant treatment showed great promise as a pre‐treatment to cutting for hay making although formic acid may have limited value when a crop is to be harvested directly for silage or artificial dehydration.In an appendix, the efficacy of using accumulated vapour pressure deficit as a basis for comparing the water loss from the untreated cut crops drying under different conditions is demonstrated.
A. low‐cost, communal grazing design for preliminary evaluation of grazing systems
Authors: MICHALK D. L. , McFARLANE J. D. 
Published: April 2006

AbstractA field design using a decagonal geometric shape is described which enables twenty small plots, each 0.08 ha in size, to be evaluated under communal grazing condilions. The decagonal design was compared with a conventional design using botanical composition and plant density as discriminating parameters. The results showed that communal grazing in the decagonal design gave similar botanical composition and plant density as the conventional design. Since less materials per treatment were used in the decagonal design, it offers a means of minimizing costs in preliminary screening experiments. However, since animal production cannot be monitored under communal grazing the most successful treatments would have to be further evaluated using the conventional approach.
The validity of in vitro techniques using rumen fluid or cellulase for predicting changes in the dry matter digestibility of grasses caused by fertilizer calcium, sulphur, phosphorus and nitrogen
Authors: REES M. C. , MINSON D. J. 
Published: April 2006

AbstractSixty‐four samples were used to measure the accuracy of in vitro techniques using rumen fluid‐pepsin or pepsin‐cellulase for predicting digestibility of grasses grown with different levels of fertilizer calcium(Ca), sulphur(S), phosphorus (P) and nitrogen (N). In each case, fertilizers changed in vivo dry matter digestibility (DMD) and the in vitro techniques accurately predicted the changes in in vivo DMD caused by fertilizer Ca, P and N. The in vitro techniques gave biased estimates of in vivo DMD in studies with fertilizer S. This bias was caused by a decrease in the digestive efficiency of the sheep when fed the unfertilized feed. It was concluded that biased estimates of DMD may be associated with low fertilizer levels and these cannot be eliminated by improving the in vitro techniques and would also apply to estimates of DMD based on chemical analysis of the feed.
Variations in composition of pasture herbage
Authors: THOMPSON J. K. , WARREN R. W. 
Published: April 2006

AbstractChanges in the chemical composition of pasture samples from five dairy farms were observed over a 2‐year period. Many of the minerals were at their lowest concentration in samples taken in the spring and early summer. At these times the concentrations of P, Mg and Na were often less than sufficient to meet the calculated requirements of the dairy cow fed on pasture alone. Cu and Co concentrations in the herbage were also generally low relative to the needs of the dairy cow.
Survivor populations of S23 perennial ryegrass from zero‐grazed and set‐stocked swards
Authors: PIKE A. , McNEILLY T. , PUTWAIN P. D. 
Published: April 2006

AbstractPerennial ryegrass tillers were collected from intensively used set‐stocked and zero‐grazed leys and from an old permanent pasture, grown on and compared at 30 cm spacing. All swards except the permanent pasture had been sown with cv. S23 and were of known age, ranging from 6 months to 11 years from sowing.Each genotype was scored for date of inflorescence emergence, and subsequently in vitro dry matter digestibility (DMD), D‐value of green leaf and the ratio of leaf dry weight: stem dry weight were determined.Both DMD and D‐value declined significantly in green leaf samples of populations from the older zero‐grazed swards but no significant changes were detected in populations from set‐stocked swards. In set‐stocked populations there was a shift towards later flowering.In zero‐grazed populations there was a consistent increase in the amount of leaf relative to stem with the age of the sward from which the plants were sampled. The survivor plants were more prostrate and leafier and it is suggested that under zero grazing, where cutting was to a uniform height, plants of this form were less severely defoliated and thus at a selective advantage.
The effects of asulam, frond cutting and ground mineral phosphate on the yields of swards dominated by bracken [Pteridium aquilinum (L.) Kuhn]
Authors: WILLIAMS GARETH , FRASER DOUGLAS 
Published: April 2006

AbstractTwo methods were adopted of measuring sward output, following the prevention of bracken frond growth, with differing results. Accumulated growth estimation, corresponding to production under a system of open‐range grazing, showed that asulam used for frond control had no effect on herbage yield in the year of application and large increases were observed in succeeding years compared with untreated control plots. In measuring production by sward regrowth after cutting, corresponding to intensive pasture utilization systems, asulam reduced yields in the year of treatment and increases were not observed until 2 years later. The inhibition of growth could be overcome by applying ground mineral phosphate at rates of 300 or 500 kg ha‐1 before spraying but the 500 kg ha‐1 rate showed no advantage over 300 kg ha‐1. Applications of ground mineral phosphate after spraying had no effect on sward output.It is concluded that indigenous pasture plants in bracken‐infested areas of western Scotland cease growth by mid July unless subjected to major earlier defoliation or severe soil moisture deficits and the removal of the frond canopy does not change this pattern significantly. Obtaining the full benefit of bracken clearance depends on making use of the resulting production of extra herbage and limiting as far as possible frond regrowth in treated areas.
Photosynthesis, respiration and nitrogen fixation in white clover
Authors: HAYSTEAD A. , KING J. , LAMB W. I. C. 
Published: April 2006

AbstractAn apparatus in which shoot and root CO2 exchange and acetylene reduction can be simultaneously measured in specific white cloverrhizobium associations is described. In mature stolonating clover there was a fairly constant ratio between net photosynthesis, root respiration and acetylene reduction. Of the net carbon fixed daily (12 h light of 80 W m‐2, 400–700 nm; day/night temperature 15°C) 12% was lost during the dark period by the shoot and 17% by the nodulated root. Changes in the rate of acetylene reduction by nodulated root systems occurred more slowly than those in rates of root respiration in response to reduced irradiance. In 21·5 h continuous darkness the rate of acetylene reduction remained constant. Responses to increased irradiance were more immediate in both root respiration and acetylene reduction. In plants maintained at 15°C in a 12‐h, 80‐W m‐2 photoperiod there was no significant diurnal variation in acetylene reduction or root respiration. Acetylene depressed root respiration by 20%. Assuming the energy requirement of the nitrogenase system to be the same when reducing acetylene and N the depression can be used as an indication of the energy requirement of fixed N assimilation, metabolism and export in the nodulated root. Of the net carbon fixed daily 3·4% was utilized in this way in plants growing in a 12‐h photoperiod (80 W m‐2, 400–700 nm) at 15°C.
The relationship between the rate of fertilizer nitrogen applied to grassland and milk production; an analysis of recorded farm data
Authors: HAWKINS S. W. , ROSE P. H. 
Published: April 2006

AbstractThe milk yields obtained from 845 herd‐years within the ICI Recorded Farms Scheme have been correlated, by multiple regression analysis, with the N fertilizer supplied to the grassland, the quantities of concentrates fed and the stocking rates. The large quantity of data gave highly significant correlations which indicated that, over the whole period, the supply of an extra 1 kg N from fertilizer was associated with an average extra yield of 9·9 1 milk. 4·9 1 were associated with the extra N independently of any simultaneous changes in either stocking rate or concentrate feeding, and 4‐5 1 were ascribable to a simultaneous increase in stocking rate. There was a substantial variation in the ‘milk yield per kg N’ response from year to year, but the average value over 6 years agreed closely with that observed in the period 1949–52.
The effect of drying techniques on formononetin concentration in red clover
Authors: JONES R. 
Published: April 2006

AbstractOven‐drying at 60°, 80° or 105°C was compared with microwave and freeze‐drying as a method of preparing samples for the estimation of formononetin, the major oestrogenic factor in red clover. There was no significant difference in the formononetin concentration of clover samples either oven‐dried at 60°C or freeze‐dried. The formononetin concentration was reduced by drying at higher temperatures and by microwave‐drying but was not affected by wilting for up to 8 h after harvesting. The routine determination of formononetin in ten varieties of red clover showed no significant differences between samples cold stored at – 18°C prior to oven‐drying at 60°C and samples freeze‐dried.
Effects of rates and times of application of starter dressings of nitrogen fertilizer to surface sown perennial ryegrass‐white clover on hill peat
Authors: HAYSTEAD A. , MARRIOTT CAROL 
Published: April 2006

AbstractThe effects on clover and grass growth of five levels of ammonium nitrogen (NH4‐N) applied before sowing, at sowing and after nodule initiation have been investigated. A pot experiment in which S184 white clover was grown in a peat soil showed that NH4‐N up to 688 mg N per pot (approx. equivalent to a field rate of 120 kg ha‐1 N) applied before sowing and at sowing did not affect clover growth. N‐fixing activity (C2H2‐reduction), on the other hand, was reduced progressively up to the highest level (688 mg N per pot). Application after nodule initiation increased growth relative to the zero‐N treatment at all levels of application. Maximum growth and N fixation occurred at 516 mg N per pot where the DM yield was 70% higher than in the absence of added N. A field trial in which S184 clover and S24 perennial ryegrass were surface sown on to a peat soil showed an increase in grass and clover growth in the first year in response to 120 kg ha‐1 N applied at sowing. Grass growth alone was increased at 120 kg ha ‐1 N applied 40 d before sowing. Lower rates of application before sowing and at sowing did not affect clover or grass growth. The effect of the delayed application of NH4‐N on legume growth was less marked than that in the pot experiment, 90 kg ha‐1 N stimulating clover growth by 40% in the first year. The effect was however different from that in the pot experiment, in that, whilst 30kg ha‐1 N increased N fixation relative to the zero‐N treatment, plants exposed to higher levels showed a depression in N‐fixing capacity. N‐fixation was correlated with nodule numbers in the delayed NH4‐N application, the closest correlation being with the number of multilobed nodules which was highest at 30 kg ha‐1 N and lowest at 120 kg ha‐1 N.It is suggested that circumstances exist when the use of a relatively low starter N dressing (20–60 kg ha‐1 N) at sowing would not increase clover or grass growth in the early stages of the establishment of a hill reseed. Under such circumstances higher rates of application (100 kg ha ‐1 N), preferably delayed until the seedlings are in a position to take up the nitrogen rapidly, would have the greatest effect.
The effect of daily herbage allowance and sward characteristics upon the ingestive behaviour and herbage intake of calves under strip‐grazing management
Authors: JAMIESON W. S. , HODGSON J. 
Published: April 2006

AbstractMeasurements of herbage intake and ingestive behaviour were made on British Friesian calves 4–9 months old, which were strip‐grazed on swards of S24 perennial ryegrass at three (Experiment A) or four (Experiment B) levels of daily herbage allowance in three (A) or four (B) 12‐d periods. Herbage intake declined by approx. 18% as daily herbage allowance was reduced from 90 to 30 g DM per kg LW in both experiments, but the relationship between intake and allowance was not consistent between periods.Bite size and rate of biting were greater in calves on low than on high allowances after entry to a new strip of herbage but the positions were reversed towards the end of grazing. Reduced herbage intakes at low allowance resulted from reductions of approx. equal magnitude in bite size, rate of biting and grazing time, though not all of these effects were significant. It is suggested that these responses result from the increasing difficulty of prehending and ingesting herbage as swards are grazed down. The calves at low herbage allowances did not increase grazing time, probably because their behaviour was conditioned by anticipation of a new allowance of herbage.Bite size and daily herbage intake were greater on a spring sward than on an autumn sward, but within experiments herbage intake was not consistently related to any of the sward characteristics measured.
Silage and milk production: comparisons between grass silage of three different chop lengths
Authors: CASTLE M. E. , RETTER W. C. , WATSON J. N. 
Published: April 2006

AbstractThree grass silages of different chop lengths made from a uniform sward of S23 perennial ryegrass were compared in four experiments including a feeding experiment with twelve lactating cows, an eating behaviour study, a rate of passage investigation and a selection trial. The silages had median chop lengths of 9·4, 17·4 and 72·0 mm, termed short, medium and long, with pH values of 3·93, 3·94 and 4·17 and D‐values of 65·9, 65·2 and 64·4 respectively.The daily intakes of silage DM and the daily milk yields increased as silage chop length decreased. The milk yield response to shorter chopping was significant with a supplement of groundnut but not significant with a supplement of sugar‐beet pulp. Chop length had small and generally non‐significant effects on milk composition.Eating and ruminating times expressed as min per kg DM decreased as silage chop length decreased but the retention time of the silage residues in the entire digestive tract was not significantly affected by chop length. When offered simultaneously, the intakes of the individual silages were 52·2, 31·9 and 15·9% of the total DM intake for the short, medium and long treatments respectively.Although silage with a chop length of 9 mm had nutritional advantages over longer silages, it is concluded that the mechanical and economic aspects of silage making must be considered fully when defining optimum chop length.
Concentrate supplementation, and the herbage intake and milk production of heifers grazing Cenchrus ciliaris
Authors: COMBELLAS J. , BAKER R. D. , HODGSON J. 
Published: April 2006

AbstractFriesian heifers grazing Cenchrus ciliaris cv. Biloela were supplemented with 0, 3 or 6 kg concentrates daily during weeks 10–34 (±1·7) of lactation during either the rainy or the dry season. The overall responses to concentrate were identical between seasons at 0·27 kg extra milk and solids corrected milk per kg. Supplementation increased total feed intake and modified the grazing behaviour of cows. For each kg concentrate organic matter eaten, herbage organic matter intake was reduced by 0·64 and 0·42 kg in the rainy and dry seasons respectively and the time spent grazing by 11 min. Higher intakes in the dry season were the result of an increased rate of biting and were reflected in liveweight change but not milk yield.
Effect of time of spraying of glyphosate on the vegetation of an upland deep peat soil
Authors: WILLIAMS GARETH H. 
Published: April 2006

AbstractThe vegetation of an upland deep peat soil consisting mainly of Festuca rubra, Holcus mollis, Molinia caerulea, Juncus acutiflorus and Potentilla erecta was sprayed with 1·5 kg a.i. per ha glyphosate applied to separate plots at monthly intervals from April to August. In July of the following year, April and May applications showed no effect on sward composition while June, July and August treatments resulted in increasing proportions of mosses and bare ground. August spraying gave almost complete control of the indigenous species with the exception of F. rubra and mosses. The results are discussed in relation to the establishment of improved pastures in upland areas by surface seeding.
The effects of cereal supplementation of grass and maize silages
Authors: VADIVELOO J. , HOLMES W. 
Published: April 2006

AbstractGrass and maize silages were fed alone and with two levels of a barley supplement to Friesian steers of about 300 kg liveweight. The organic matter (OM) intakes of grass and maize silage were similar although the OM digestibilities of the silages were 0·722 and 0·649 respectively. For both silages, barley supplementation increased total OM intake and total digestible OM intake by 0·46·0·08 and 0·37·0·06 g per g OM of supplement respectively. Liveweight gains on grass and maize silage diets were 1·38 and 1·20 kg d‐1 respectively, but the differences were not significant (P> 0·05).
Changes in dry matter yield associated with selection for canopy characters in ryegrass
Authors: RHODES I. , MEE S. S. 
Published: April 2006

AbstractStudies have been carried out to measure the response to selection for canopy characters, as measured on young spaced plants, and the associated changes in sward yield in Lolium. In addition certain of the selection lines were compared with and found to be more productive than several existing bred varieties, indicating the considerable scope for improvement of dry matter yield through breeding.The canopy characters which were associated with high yield are compared with those which confer high yielding ability on a spaced plant and an individual in a community. The plant breeding implications of the results are briefly discussed.
The response of Lotus uliginosus L. grown on hill soils to inoculation with Rhizobium
Authors: GWYNNE D. C. , BECKETT ROSEMARY E. 
Published: April 2006

AbstractThe response of marsh birdsfoot trefoil (Lotus uliginosus) to inoculation with appropriate Rhizobium spp. was compared over 2 years. Inoculated and uninoculated seed was sown at 5 kg ha‐1 on three soil types, brown earth, peaty podsol and deep peat. Perennial ryegrass cv. Perma was sown at 20 kg ha‐1 as a companion species. Plots received either no N or a light starter dressing of 30 kg ha‐1 N. Significant benefits from inoculation were recorded for Lotus germination and nodulation, Lotus and non‐Lotus herbage DM harvested and Lotus cover on the deep peat, and to a lesser extent on the other soil‐types. Due to particularly uneven early establishment, work on the peaty‐podsol site was discontinued at an early stage. There was a trend towards depression of Lotus where N had been applied to inoculated plots.