bluuebunny/crossref_metadata_2025_split huggingface dataset:
The diet ingested by sheep grazing swards differing in white clover and perennial ryegrass content
Authors: MILNE J. A. , HODGSON J. , THOMPSON R. , SOUTER W. G. , BARTHRAM G. T. 
Published: April 2006

AbstractA series of twenty‐four swards containing different proportions of white clover (0·20‐0·25) and perennial ryegrass were created by using different seed mixtures, herbicide applications and previous cutting Frequencies. These swards were used to study the diet of oesophageally‐fistulated wether sheep which grazed the various swards for a 30‐min period after 1, 2 and 3 weeks of regrowth.The proportion of white clover in the diet was generally greater than that in the sward. Fifty‐seven percent of the variation in the proportion of white clover in the diet could be attributed to the proportion of white clover in the sward. White clover and perennial ryegrass leaf and stem were grazed to the same height and the proportion of white clover in the grazed horizon of the sward explained 83% of the variation in the proportion of white clover in the diet. The proportion of white clover in the diet was greater than the proportion in the grazed horizon of the sward in week 3 of regrowth, but not in weeks 1 and 2, and greater when the proportion of white clover in the grazed horizon was lower than 0·20. Both these observations were interpreted as indicating selection for white clover by the sheep within the grazed horizon.There was a positive and linear relationship between the depth of the grazed horizon and sward height which, together with the relationship between the proportion of white clover in the grazed horizon and in the diet, would allow the prediction of the proportion of white clover of the diet from the height and the white clover content of the grazed horizon of the sward.
Soil moisture and growth of contrasting varieties of Lolium, Dactylis and Festuca species
Authors: NORRIS I. B. 
Published: April 2006

AbstractVarieties of Italian, perennial and Italian × perennial ryegrasses, tall fescue and cocksfoot were used to determine the effects of soil moisture on grass growth. Weather conditions were monitored and herbage accumulation, leaf extension rate, leaf appearance rate and tillering were recorded under natural (control), covered and irrigated treatments.Water deficit reduced crop growth rate in the spring and drought was the major factor influencing crop growth rates in all varieties during the summer. The ryegrasses appeared most sensitive to drought, and particularly poor recovery growth was exhibited by the Italian ryegrass RvP and the hybrid ryegrass Snowdon.Leaf extension rate and leaf appearance rate were both reduced by increasing soil water deficit. Herbage accumulation was increased by irrigation when potential soil water deficits were greater than 100 mm. When water deficits were large, irrigation increased leaf extension more than leaf appearance or tiller number. Increasing moisture deficit had a greater effect upon tiller number than on leaf extension.
The influence of selected agronomic factors on the yield of forage peas
Authors: POTTS M. J. 
Published: April 2006

AbstractFive trials were carried out in 1979 to assess the influence of cultivar, seed rate, fertilizer application and the inclusion of oats as a companion crop on the dry matter (DM) yield of forage peas grown in the west of Scotland. Despite the season being abnormally cold the crop consistently produced between 6 and 8 t DM ha‐1. There was little difference between cultivars in the yield of forage produced but there were considerable differences in the time taken to reach maturity. All cultivars lodged. There was no yield response to seed rate of between 80 and 280 kg ha‐1 nor to fertilizer N and K applications. The inclusion of oats in the seeds mixture greatly reduced lodging and had no marked effect on DM yield but the organic matter digestibility and crude protein concentration were lower than recorded for peas grown alone in previous years.
Relationship between competitive ability and yielding ability in mixtures and monocultures of populations of Dactylis glomerata L
Authors: EAGLES C. F. 
Published: April 2006

AbstractSwards were developed from plants of contrasting populations of Dactylis glomerata L. selected for high and low dry‐matter (DM) production in monocultures and mixed cultures grown during 1970 and 1971. DM production of these mono‐genotype swards was assessed during 1974. Those swards developed from the divergent selections from monocultures maintained a significant difference between the high and low selections, whereas those developed from selections out of mixed cultures showed no significant difference in yield. These results are consistent with earlier reports that there is no positive relationship between competitive ability in mixed cultures and vigour in pure stands. The implications of the physiological basis of these responses in terms of grass breeding are discussed.
A comparison of the nutritive values of early and late varieties of timothy
Authors: MÍKA V. 
Published: April 2006

Abstract In vitro digestibility, fibre, lignin and protein were determined in 50 varieties of timothy differing markedly in maturity date. The grasses were field‐grown as single plants and were sampled at 10% ear emergence, 30% flowering and the mature seed stage and were compared in four groups according to date of ear emergence.Significant differences were found between maturity groups in digestibility and protein concentration particularly at the earlier growth stages. Considerable variation also occurred within maturity groups. Differences in digestibility, fibre, lignin and protein were significantly correlated with the number of days between 30 April and harvest date.The results are discussed in the context of an appropriate evaluation scheme for timothy varieties.
Productivity of mixtures of Italian ryegrass and red clover
Authors: CAMLIN M. S. , GILLILAND T. J. , STEWART R. H. 
Published: April 2006

AbstractTwo red clover (Trifolium pratense) cultivars, Red Head (tetraploid) and Kuhn (diploid), were sown at a seed rate of 13 kg ha−1 either alone or in mixture with Italian ryegrass (Lolium multiflorum) cv. RvP sown at seed rates of 10, 15, 20 or 30 kg ha−1. RvP was also sown alone at a seed rate of 30 kg ha−1 and received nil or 300 kg ha−1 fertilizer a−1 fertilizer N. All plots were established using the barley cultivar Midas sown at a seed rate of 100 kg ha−1 as a nurse crop.Neither clover cultivar nor ryegrass seed rate significantly influenced either dry matter harvested or botanical composition over the 3 harvest years. On average over all years the grass‐clover mixtures produced 75% of the yield of the N‐fertilized RvP, 125% of the clover monocultures and 225% of the unfertilized RvP. The red clover contribution to the total dry matter harvested of the mixtures averaged 45–60%. The dry matter concentrations of the mixtures were considerably higher than those of the pure clover stands. In the third year yields were markedly reduced in comparison with those in the first and second years.It was concluded that Italian ryegrass can be a suitable companion grass for red clover. Its superior yielding capacity over other grasses such as perennial ryegrass or timothy under a conservation management can be coupled to advantage with red clover to give a sward which Is essentially stable, at least over a 2‐ to 3‐year cropping period, although giving slightly reduced yields in the third year. Italian ryegrass‐red clover mixtures, without the use of fertilizer N, can produce high DM yields of good quality herbage.
The influence of water content on the stiffness and fracture properties of grass leaves
Authors: VINCENT JULIAN F. V. 
Published: April 2006

AbstractLaminae of Lolium perenne and Phleum pratense were tested mechanically and the results analysed using engineering composite theory and fracture mechanics. As the lamina dries the fibres double in stiffness. The intervening cells show a sevenfold increase in stiffness below 20% water content (based on dry weight). Work to fracture across the veins is almost independent of water content, but below 50% water content the mode of fracture changes. It is predicted that total fibre content will not affect hay shatter; total protein content may affect it by altering the water‐binding properties.
Effects of the amount of barley and time of access to grass silage on the voluntary intake, eating behaviour and production of dairy cows
Authors: HARB M. Y. , CAMPLING R. C. 
Published: April 2006

AbstractThree separate changeover experiments were conducted to investigate the effect of the amount of rolled barley and time of access to silage on the voluntary intake, eating behaviour and production of dairy cows. In Experiment 1, twenty‐four milking cows were used to compare the effect of 4 1 and 6 1 kg d−1 rolled barley on voluntary intake and milk production. In Experiment 2, fourteen cows were used in a comparison of the effect on voluntary intake and milk production of 5‐ and 22‐h access to silage. Experiment 3 measured the effects on intake of silage of 2 and 4 kg d−1 rolled barley and of 5‐ and 22‐h access to silage. In Experiment I, increasing the amount of barley eaten reduced intake of silage by 0–50 kg dry matter (DM) per kg barley DM but in Experiment 3 with 5‐h access to silage there was no significant difference between the amounts of silage eaten with 2 and 4 kg d−1 barley. However, in Experiment 3 when allowed 22‐h access to silage, the replacement rate was 0–53 kg DM silage per kg DM barley. Increasing access from 5 to 22 h increased silage intake by 37% in Experiment 1 and by 27% in Experiment 3. Milk yield was significantly increased by 4% when extra barley was given in Experiment 1 but there was no significant effect in Experiment 3. Increasing the time of access to silage led to an 11% increase in milk yield in Experiment 2 but there was no significant effect in Experiment 3. There was much variation between cows in the depression of silage intake per kg change in barley DM eaten with coefficients of variation of 131% and 109% in Experiments 1 and 3, respectively. When allowed access to silage for 22 h daily, on average, each cow spent 180 min eating silage in ten meals, although there was appreciable variation between cows in eating behaviour. The amount of barley did not affect the cows' rate of eating silage nor the duration of eating.
A model of the anaerobic phase of ensiling
Authors: NEAL H. D. ST C. , THORNLEY J. H. M. 
Published: April 2006

AbstractA model of ensiling is described which incorporates the interactions of lactic acid bacteria and Clostridia with water soluble carbohydrates. The processes modelled include bacterial growth, the production of lactic and butyric acids from water soluble carbohydrates, and the conversion of lactic acid to butyric acid. The calculation of pH, and the regulation of bacterial activity by pH are important components of the model. The model predicts time courses for pH and the five State variables, which are the concentrations of water soluble carbohydrates, lactic acid, butyric acid, lactic acid bacteria and Clostridia. There is good qualitative agreement between the predictions of the model and experimental data on ensiling.
Putting an economic value on increases in grass production
Authors: DOYLE C. J. , ELLIOTT J. G. 
Published: April 2006

AbstractAn attempt was made to determine monetary values for grass which might be used by researchers to assess the likely economic implications of their findings. It is shown that the value of extra grass production will vary considerably depending on the use made of it. At 1982 price levels, estimated values for grass in the field ranged from 1–4 to 10–6 pence kg−1 DM, with a modal value around 3–5 pence kg−1 DM. At the same time, the seasonal distribution of the extra grass production is important since the value of extra grass at different points in the growing season may vary markedly. The way in which these values for grass may be used is illustrated, using as an example weed control during sward establishment. Finally, the sensitivity of investment returns to changes in the value placed on grass is discussed. Extreme caution is necessary in drawing general conclusions about benefits and costs from an evaluation based on a specific value for grass.
Sward structure changes within a perennial ryegrass swara: leaf appearance and death
Authors: VINE D. A. 
Published: April 2006

AbstractThe appearance of successive leaves on labelled tillers of S24 perennial ryegrass, and their subsequent death, were monitored for 1 year on cut plots on which four levels of N fertilizer were applied.A new leaf appeared about once every 15 d from the end of April until the beginning of September, and about once every 52 d from the end of October to the middle of February. Rate of appearance changed rapidly during September and October, and again from mid‐February until the end of April. The response of leaf appearance rate to temperature changed early in the year; the effect of overwintering is discussed.Leaf lifespan was 50–60 d in summer and 120–140 d in autumn and early winter, and was influenced by conditions either during expansion of the leaf or shortly afterwards.The results are discussed in relation to the construction of a model to describe changes in the herbage available to animals grazing a grass sward.
The effects of spring closing date on the yield and quality of perennial ryegrass and cocksfoot cut for conservation
Authors: SWIFT G. , EDWARDS R. A. 
Published: April 2006

AbstractThis second paper concerned with effects of prolonged spring defoliations on two early perennial ryegrass varieties (Cropper and RvP Hay Pasture), an intermediate perennial ryegrass (Talbot) and an early cocksfoot (Roskilde) examines the effects of different closing dates on ear emergence, weekly DOMD (in vitro) and conservation yields. The grasses were mown fortnightly to simulate sheep grazing from January until three closing dates, 19 April, 3 May or 17 May, in 1978 and 1979. A set of plots was left undefoliated. All plots were sampled weekly from 2 or 3 weeks after 17 May until the end of June or early July.Prolonged mowing resulted in a small delaying effect on 50% ear emergence of the ryegrasses. The maximum delay was 3 d with the latest closing date. Under this treatment, ear emergence of the cocksfoot was delayed by an average of 12 d but by only 0–4 d under the earlier closing dates. Delay in date of closing caused a significant delay in the time to reach a given DOMD but the effect was largely confined to the latest closing date and was greatest for the cocksfoot. The time when 670 g kg−1 DOMD was reached was delayed in the ryegrasses by no more than 5 d, except for a 12‐d delay in the intermediate ryegrass in 1978 following the late closing date. Under this treatment the delay for the cocksfoot was 8 d in both years. The early ryegrasses produced stemmy regrowths.
The integration of conservation with grazing for milk production: a computer simulation of the practical and economic implications
Authors: DOYLE C. J. , CORRALL A. J. , THOMAS C. , LE DU Y. L. P. , MORRISON J. 
Published: April 2006

AbstractEarlier studies have concluded that for a dairy enterprise the most profitable conservation strategy, where cutting and grazing areas are separate, is generally associated with relatively low‐digestibility silage. The aim of this study has been to investigate whether this conclusion remains true where cutting and grazing are integrated. A mathematical model of grass production and utilization by a dairy enterprise has been developed from information collected from a variety of experimental sources. It was found that cutting strategies aimed at making low‐digestibility silage could not automatically be regarded as the most profitable. In good grass‐growing conditions strategies resulting in low‐digestibility silage did appear to offer the highest gross margins per unit area, but under average and poor growth conditions the greatest profits were associated with high‐digestibility silage strategies. In particular, it was noted that the timing and frequency of conservation cuts influenced the efficiency with which grass could be utilized on the grazing areas and this fact rather than yield of conserved material influenced the comparative biological and economic efficiency of the different cutting strategies.
The antimicrobial spectra of some salts of organic acids and glutaraldehyde in respect to their potential as silage additives
Authors: WOOLFORD M. K. 
Published: April 2006

AbstractSalts of formic, acetic and propionic acids and glutaraldehyde were subjected to an assay with representatives of the major groups of silage micro‐organisms at pH 4·0, 4·5, 5·0 and 6·0. The antimicrobial spectra of the salts suggested that they are most effective against the least desirable components of the bacterial flora of silage, coliforms, Clostridia and bacilli, and would create conditions for a desirable fermentation in practice. In many instances the activity of the salts was better than the corresponding free acid and it was postulated that, if supplemented with acid, aerobic stability of silage might also be improved. Glutaraldehyde, whilst being less selective as an antimicrobial agent, possesses properties which would encourage a lactic‐acid fermentation in silage.
Silage and milk production: a comparison between concentrates containing different amounts of protected protein as supplements for silage of high digestibility
Authors: CASTLE M. E. , WATSON J. N. 
Published: April 2006

AbstractGrass silage made in late May from S24 perennial ryegrass was offered ad libitum to eight Ayshire cows in a 16‐week feeding experiment. The silage had a DM concentration of 244 g kg−1, contained 163 g crude protein (kg DM)−1 with a ruminal degradability of 0.77 and had an in vitro DOMD concentration of 678 g kg−1. In addition, four concentrates each containing 167 g soya‐bean meal kg−1 were consumed at a mean daily rate of 6.43 kg DM per cow. The soya‐bean meal was either untreated, or ‘protected’ by formalin and mixed in the following proportions, 100:0; 66:34; 34:66; and 0:100 respectively, in the four concentrates. The daily intakes of silage DM were not significantly different on the four treatments and averaged 90 kg DM per cow, giving a mean total daily DM intake of 32.4 g kg−1 live weight. The milk yields were not significantly different on the four treatments and averaged 23.9 kg −1 The treatments had small and non‐significant effects on milk composition and live weight. It is concluded that with a high‐digestibility, well‐preserved grass silage of satisfactory protein content the inclusion of ‘protected’ protein in the supplementary concentrate had no beneficial effects on milk production.
Productivity of red clover grown alone and with companion grasses; further studies
Authors: McBRATNEY J. M. 
Published: April 2006

AbstractThree diploid—Sabtoron, Violetta and Essex—and three tetraploid—Hungaropoly, Teroba and Red Head—red clover cultivars were sown alone and with each of three companion grasses—timothy (S48), tall fescue (S170) and perennial ryegrass (S24). The productivity and persistence of the red clover cultivars were compared. Results obtained over the first four harvest years were presented in an earlier paper (McBratney, 1981) and this paper presents results from the fifth and sixth (final) harvest years.The low yield obtained in the fifth and sixth year from Essex under each seeding treatment indicated a deterioration in its persistency or vigour or both. In the fifth year the remaining two diploids, Sabtoron and Violetta, were as highly productive and persistent as the three tetraploids but in the sixth year the decrease in productivity was greater in the diploids than in the tetraploids. In the fifth year Teroba, the highest yielder, produced 9 8 t total DM ha−1 over all seeding treatments of which 73% was clover DM; in the sixth year Teroba was again highest yielding, producing 9.3 t ha−l with 67% clover content. Tall fescue was the most consistent companion grass in the mixed swards, in the sixth year contributing 53% grass DM to the total 8 8 t DM harvested ha−1.The trial demonstrates the potential of a number of red clover cultivars grown either pure or with a suitable perennial grass to achieve and maintain a high output of herbage of good quality over a period of 6 years without any application of fertilizer N. The practical agricultural implications of using red clover are discussed.
Herbage yield and animal production from grassland on three commercial dairy farms in South‐East England
Authors: PEEL S. , MATKIN ELIZABETH A. 
Published: April 2006

AbstractYields of grass were measured on three dairy farms in 1981. Farm 1, on free‐draining loamy soil over chalk, produced 10.3 t DM ha−1 using 336 kg N ha−1. Farm 2, on poorly‐drained loam over Oxford clay, produced 12.8 t DM ha−1 using 354 kg N ha−1. Farm 3, on loam over clay with some free‐draining sandy loam, produced 9.5 t DM ha−1 with 169 kg N ha−1. Allowing for differences in soil nitrogen and summer rainfall these yields were quite close to expectations from experimental results, despite considerable poaching damage to some swards.Animal production records were kept and all livestock were weighed every 6 months, so as to calculate the utilized metabolizable energy (UME) output from grassland on each farm. These were 73, 62 and 59 GJ ha−1 on farms 1, 2 and 3 respectively.The UME output, expressed as a proportion of the yield of grass (converted to ME), was taken as the ‘efficiency of utilization’ of grass. This was 70% on farm 1,44% on farm 2 and 58% on farm 3. Results are presented separately for the summer and winter 6 months. Utilization by grazing appeared to be markedly reduced under very wet soil conditions. Major losses occurred in the conservation of grass.The results begin to establish a valuable base of data from commercial farms.
The influence of seed rate and pesticides on the establishment and growth of white clover slot‐seeded into a permanent pasture
Authors: WILLIAMS E. D. 
Published: April 2006

AbstractThe establishment and growth of white clover (cv. Grasslands Huia) was investigated in two experiments with seeds sown in slots cut in old permanent pasture in early May 1982. In the first experiment, fully protected from pests and diseases, either 50 (low), 100 (medium) or 200 (high) seeds were sown evenly per metre length of slot; 100 seeds were also sown in a clumped pattern unevenly. In the second experiment, the effects of various combinations of molluscicide, insecticide and fungicide were investigated.Nine weeks after sowing there were 27, 37, 34 and 62 seedlings m−1 on the low, medium even, medium uneven and high seed‐rate treatments, representing percentage establishments of 54, 37, 34 and 31 respectively. By September, however, there were no significant differences between the dry weights m−l of any of the treatments. In the second experiment, damage by slugs occurred early in treatments without molluscicide and caused a mean reduction of 70% in seedling establishment. As a result significantly smaller dry weights m−1 of clover were recorded in September in these than in other treatments. Failure to protect against insects resulted in smaller seedlings.The results indicated that variations in seed rate within the range investigated were not critical but that failure to protect against pests decreased percentage establishment and subsequent growth.