bluuebunny/crossref_metadata_2025 huggingface dataset:
A comparison of methods of establishing swedes following an early silage cut
Authors: EASSON D. L.
Published: April 2006

Experiments were carried out over three seasons in which swedes were sown by precision drilling after ploughing and conventional cultivation or by direct drilling with two types of drill at two row widths with and without shallow cultivation. The swedes were sown in June or early July following a first silage cut and sward desiccation with paraquat. Precision drilling with inter‐row cultivation and singling gave a uniform weed‐free stand and had the highest mean yield of over 8 t DM ha−1 Where hoeing was omitted yields were reduced due to weed competition. Yields following direct drilling were lower than with precision drilling due to uneven plant establishment, weed competition and grass regrowth. A shallow rotavation prior to direct drilling improved uniformity and yields and reduced grass regrowth. Direct drilling produced high numbers of small roots. The highest root yields were associated with sowing in early June and harvesting in December or January. Overall yields from the silage cut plus direct drilled swedes and silage cut plus precision drilled swedes were 12 and 13 t DM ha−1respectively compared with about 14 t DM ha−1expected from a grass sward.
The nature of competition between perennial ryegrass and white clover
Authors: MARTIN M. P. L. D. , FIELD R. J.
Published: April 2006

Perennial ryegrass and white clover were grown in boxes with either no competition, root competition only, shoot competition only, or both root and shoot competition between them, Boxes received either no nitrogen or 200 kg N ha−1 as a split application. The experiment was harvested at 8, 12, 16 and 20 weeks after sowing. Perennial ryegrass was more competitive than white clover throughout the experiment and its overall competitive ability increased with Lime. The effects of root competition were greater than those of shoot competition at the first harvest, with both forms of competition having similar affects at the second harvest, while at the third and final harvests shoot competition had greater effects than root competition. At the later harvests N application increased the overall competitive ability of perennial ryegrass, relative to white clover, mainly owing to the increase in its shoot competitive ability.
The effect of autumn fungicide application on spring dry matter accumulation in perennial ryegrass cv. S24
Authors: HAMPTON J. G. , HEBBLETHWAITE P. D.
Published: April 2006

Fungicide applied to plots of perennial ryegrass cv. S24 in the autumn of 1981 significantly increased tiller number and total dry matter accumulation in February and March of 1982. However, fungicide application in the autumn of 1982 failed to increase tiller number or dry matter accumulation in the spring of 1983. It is suggested that fungicide application in autumn 1981 prevented the death of tillers caused by fungal attack after snow covered the plots in December 1981.
Herbage losses from tiller pulling in a continuously grazed perennial ryegrass sward
Authors: TALLOWIN J.R.B.
Published: April 2006

Tiller pulling was studied in a perennial ryegrass sward that was continuously grazed by cattle. The treatments included severe (sward height after grazing 25 mm), medium (50 mm) or lenient (75 mm) grazing from turn‐out in April to 1 June, followed by grazing to 50 mm in the remainder of the season. Tiller pulling was confined to the midsummer‐autumn period of the grazing season. The losses were most severe in swards that had been leniently grazed to a mean height of 75 mm during the spring and least severe in swards grazed to a height of 25 mm. The lenient grazing treatment allowed both the true stem development and aerial tillering whereas in the more tightly grazed swards true stem development was significantly less and aerial tillering was virtually absent. The pulled organic matter in the lenient treatment was equivalent to about 5·3% of the total harvested yield. In the severely grazed swards, pulling losses were equivalent to about 1·7% of the total harvested yield. A high rate of turnover of the pulled herbage was found in all the treatments with between 69 and 78% of the freshly pulled herbage disappearing within a week of being pulled. Tiller pulling was found to have no effect on either the subsequent autumn‐winter tiller density or yields of cuts taken in the following year.
The effect on annual dry matter yield of using a hand‐controlled mower or a plot harvester for cutting herbage on small‐plot trials
Authors: SHELDRICK R. D. , LAVENDER R. H. , TEWSON V. J. , COBBY J. M.
Published: April 2006

A sward of S24 perennial ryegrass was sampled at 4‐weekly intervals over two seasons with either a Haldrup 1500 plot harvester or a hand‐controlled mower fitted with a fixed reciprocating cutter bar. Plot dimensions were adjusted to the width of the machines'cutter bars (1.5 m and 1.0 m respectively) so that there were no discard areas to require removal. Plots were cut either once, or twice in opposite directions. After cutting, residual stubble heights and the proportion of ground surface covered by leaf laminae were recorded.

Mean annual dry matter (DM) yields recorded in ten harvests made each year showed no overall significant difference between the machines. However, previous practice had been to sample plots with one pass of the hand‐controlled mower and to trim the sampled area while removing the usual discard strips. The comparison of annual DM yields from one cut taken with the Haldrup or from two cuts taken with the mower, but with the yield at the second cut excluded, showed a mean advantage of 1.55 t DM ha−1 a−1 for the Haldrup technique or a 14.6% increase over previous practice.

Cutting twice significantly (P<0.001) reduced herbage production by a mean of 0.85 t DM ha−1 a−1, mean residual stubble height by 9.8 mm and the proportion of ground covered by leaf laminae by 9.8%. Provided that judgment is exercised when planning treatments and layout of trials, it is concluded that the Haldrup 1500 plot harvester is a valuable labour‐saving tool. However, DM yields from trials cut frequently with this machine are likely to exceed those from similar trials cut with a hand‐controlled mower, following the usual G.R.I. Staff (1961) technique.
The effects of stocking rate and nitrogen fertilizer on a perennial ryegrass‐white clover sward
Authors: CURLL M L. , WILKINS R. J. , SNAYDON R. W. , SHANMUGALINGAM V. S.
Published: April 2006

Four stocking rates (25–55 sheep ha −1) and two N fertilizer treatments (nil or 200 kg N ha−1) were imposed on swards containing perennial ryegrass (Lolium perenne) and white clover (Trifolium repens) which were continuously stocked throughout one grazing season. These treatments gave swards that varied greatly in their content of white clover. The effects of these treatments on pasture and animal performance in the following season were examined when all plots were continuously‐stocked with 25 yearling sheep ha−1 and received no N fertilizer. There was slight regeneration of clover in the second year. Herbage growth ranged from 5.4 to 11.0 t dry matter (DM) ha−1, was closely correlated with the clover content of the swards and was higher on swards that had previously received 0 rather than 200 kg Nha−1.

The liveweight gain and wool production of sheep in the second grazing season closely reflected the herbage growth and clover content of the swards. As a result, animal production was greatest from swards which had previously been stocked at the lowest rate and had received no N fertilizer and least from swards which had been stocked at the lowest rate but had received N fertilizer.

The results show that the adverse effects of over‐grazing and N fertilizer application in one season may be partially rectified by lower stocking rates and by withholding N fertilizer in the following season.
Relationships between growth and measured weather factors among contrasting varieties of Lolium, Dactylis and Festuca species
Authors: NORRIS I. B.
Published: April 2006

Italian, perennial, hybrid ryegrass, tall fescue and cocksfoot were used to determine the influence of the weather upon grass growth. Throughout the spring and summer months of 1975 and 1976, weather conditions were monitored. Crop growth rate, leaf extension rate, leaf appearance rate and tillering were recorded. Natural (control), covered and irrigated treatments were applied. In spring, crop growth rates were correlated with solar radiation and temperature, but growth rates were greatest at high levels of insolation. Leaf extension rate was associated with temperature during spring. But during summer this association between temperature and leaf extension became confused as soil water deficit increased. Leaf extension rate in the tall fescue variety SI 70 was the slowest of all for a given temperature. In 1975 leaf growth was very sensitive to temperature; the rate of leaf appearance increased as temperature increased. In 1976 water deficit reduced crop growth rate in spring, and was the major factor influencing crop growth rates in all varieties during summer. Leaf extension and leaf appearance rates were both reduced by increasing soil water deficit. The ryegrasses appeared most sensitive to drought and poor recovery growth was found in the Italian RvP and the hybrid Snowdon.
A von Liebig response function to nitrogen and phosphorus for hay production from irrigated pastures
Authors: PARIS Q. , PARIS P.
Published: April 2006

Permanent pasture in the Po Valley of Italy was the site of a pluriannual experiment (1975–81) to observe the effects on hay production of N and P fertilizer applications well above those normally recommended. A split‐plot design with a randomized complete block arrangement of the whole‐plot factor with 5 levels of N and the subplot factor with 3 levels of P was chosen for the experiment. The maximum rate of N application was 800 kg ha−1 while the corresponding rate for P was 87.3 kg ha−1. Principal species in the sward were orchard grass (Dactylis glomerata L.), perennial ryegrass (Lolium perenne L.), common velvetgrass (Holcus lanatus L.) and white clover (Trifolium repens L.).

This field was irrigated according to customary techniques during summer months and cut five limes each year. Yields were analysed by means of a response function of the linear and plateau type which incorporates von Liebig's Law of the Minimum, it was found that this function represents the hay response very well with respect to N. In fact, beyond 390 kg ha −1 applied N the response is negligible up to 800 kg ha−1, the maximum rate tested in this experiment. The optimal rate of applied N decreased consistently over the years from 390 to 260 kg ha−1. At these unusually high levels of fertilization hay production increased about 60–80% compared with normal practices.

The estimation of the von Liebig response function requires mathematical programming knowledge. The estimates obtained are maximum likelihood estimates. The practical importance of estimating and using this response function lies in its ability to achieve the maximum response with the minimum amount of fertilizers among all other admissible response functions. Hence, its adoption for making fertilizer recommendations would save farmers money and limit chemical pollution to the environment.
A comparison of insecticide treatments for the control of frit fly in seedling ryegrass
Authors: MOWAT D. J. , JESS S.
Published: April 2006

Laboratory experiments gave useful indications of the effectiveness of insecticide treatments to control larvae of frit fly (Oscinella frit L.). Lightly infested field experiments provided confirmatory evidence. Several seed treatments, insecticide granules combine‐drilled with the seed and post‐emergence sprays were very effective. The feasibility of delivering granules with seed must be confirmed for each granular formulation. Post‐emergence sprays were most effective if applied at approximately the time of oviposition but several also gave a strong residual effect if applied earlier and a remedial effect if applied after larval establishment in the seedlings. More detailed conclusions are discussed.
An investigation into the use of ranked set sampling on grass and grass‐clover swards
Authors: COBBY J. M. , RIDOUT M. S. , BASSETT P. J. , LARGE R. V.
Published: April 2006

Four experiments were conducted to assess the performance of ranked set sampling relative to random sampling for the estimation of herbage mass and clover content in grazed swards. The expected theoretical efficiencies were not observed due to the method of selection of quadrats and the nature of the distribution of herbage mass. Nevertheless there should be worthwhile improvement in precision over random sampling, provided that the quadrats within a set are as well spaced as possible, allowing, if necessary, for visual comparison.
Comparison of the relative performance of perennial ryegrass varieties under upland and lowland conditions
Authors: DAVIES D. A. , JONES E. L. , MORGAN T. E. H.
Published: April 2006

Productivity, seasonal growth and persistence of 10 perennial ryegrass (Lolium perenne L.) varieties were assessed al an upland (305 m) and lowland (30 m) site in mid‐Wales. Averaged over 3 harvest years (1979–81), mean dry matter (DM) production at 8.8 t ha−1 was 22% lower in the upland environment, with spring (April and May) growth showing greatest contrast varying from only 6% of that in the lowland in 1979, after a severe winter, to 113% in 1981.

Relative ranking of varieties differed considerably between the two environments and no correlation was found between DM production at the two sites (r= 0.5945). Early heading varieties performed better in the spring than late types at the upland site. A comparison of the results with those published from official variety testing trials gave a positive relationship under lowland conditions (r= 0.7162*) but no correlation with those from the upland centre (r= 0.1969).

The findings of the study show that relative productivity of varieties, but not persistency, differs between upland and lowland environments.
South‐west England grassland survey 1983
Authors: HOPKINS A. , MATKIN ELIZABETH A. , ELLIS JULIA A. , PEEL S.
Published: April 2006

A survey of grassland on 127 farms in south‐west England was conducted in order to investigate the cutting and grazing management of grassland, botanical composition and the use of fertilizer N, and to quantify recent trends in reseeding and the age structure of swards. Twenty‐six percent of the grassland surveyed was classified as arable grassland (in rotation with crops) and 74% as permanent grassland. Only 37% of the established grassland on dairy farms was aged over 20 years compared with 53% on livestock farms. Mowing was practised on 52% of the grassland, two‐thirds of it every year, and virtually all grassland was grazed for part of the year. The average fertilizer N input was 168 kg ha−1with considerable variation with sward age (average 113 kg ha−1for over‐20‐year‐old swards) and between dairy farms (average 217 kg ha−1) and livestock farms (100 kg ha−1)‐ The average proportion of sown species (mainlyLolium perenne)ranged from 90% in young swards to 36% in swards aged over 20 years, with considerable variation within age groups.L. perennewas associated with high inputs of fertilizer N, good drainage, sheep grazing and organic manures, e.g. among swards aged over 20 years it contributed 38% on average where >250 kg N ha−1were applied, but only 12% where no fertilizer N was applied. A continuous network ofTrifolium repensoccurred in 27% of the grassland–this was associated with low inputs of fertilizer N, good drainage and sheep grazing.Agrostisspp. were the most abundant unsown species andCirsium arvense, Ranunculusspp. andRumexspp. the most common broad‐leaved weeds. Features of the sample are compared with those in the south‐west England region and in England and Wales as a whole.
Effects of grass defoliation on the establishment and growth of slot‐seeded white clover
Authors: BOATMAN N. D. , HAGGAR R. J.
Published: April 2006

White clover was slot‐seeded into a low‐fertility permanent pasture in May 1979. The effects of cutting interval (1, 2 and 4 weeks) and cutting height (3 and 7 cm), in the presence and absence of above‐ground partitions, were recorded in terms of clover establishment and growth up to 15 weeks. The partitions resulted in a considerable increase in growth, stolon production and survival of clover plants, especially from 6 weeks after sowing, indicating a large effect of shoot competition from the surrounding sward. However, the effectiveness of defoliation in reducing grass competition appeared limited; close cutting did give some benefit to establishing clover but cutting frequency had little effect. In view of the limited success in reducing grass competition by cutting, further attempts at alleviating root competition are needed, possibly involving fertilizer placement and the use of grass‐suppressing herbicides.
Comparison of management techniques for evaluating Italian and hybrid ryegrass cultivars
Authors: JONES E. L. , ROBERTS J. E.
Published: April 2006

The effect of management on dry matter yield and persistence of eight cultivars was assessed over a 3‐year period (1978–80) under integration of sheep grazing and simulated sheep grazing with cutting for conservation, and the two cutting frequencies used in the National List trials. A high correlation was obtained in the first and second harvest years between managements in respect of annual production, the ranking order of yield being similar for the range of cultivars. In the third harvest year yield correlation and persistence between sheep grazing and simulated sheep grazing was high and similar to previous years, but all other yield and persistence correlations were considerably reduced. A major effect of frequent cutting management used in the National List trials was the increase in the proportion of unsown grasses (mainly Poa spp.) in the swards.
Voluntary intake and in vivo digestibility by sheep of five lilies of Cenchrus ciliaris selected on the basis of preference rating
Authors: MINSON D. J. , BRAY R. A.
Published: April 2006

A study is reported on the voluntary intake and digestibility by sheep of five lines of Cenchrus ciliaris when grown as swards and cut at six different stages of growth. Previous studies with C. ciliaris grown in small rows had shown large differences between these lines in grazing preference by cattle. The ranking order for preference wasline31>10 = 23>30 = 36.

When offered singly to sheep in pens the five lines could be divided into three groups according to their voluntary intakes. Lines 10 and 30 had the highest mean daily intakes of 56·1 and 57·6 g (kg W)‐0·75 compared with lines 23 and 36 with low mean intakes of 48·5 and 48·6 g (kg W)‐0·75. Line 31 was intermediate with a mean intake of 543 g (kg W)‐0·.

Mean dry matter digestibility of the five lines ranged from 0·577 to 0·597%. Lines 10 and 30 had the lowest digestibility. The difference in intake between the five lines was positively correlated with their proportion of leaf (r= 0·97). Low‐intake lines (23 and 36) also had the highest proportion of seed head.

It was concluded that selection of C. ciliaris on the basis of preference by cattle in a cafeteria study provided no useful guide to voluntary intake when the different lines were grown, cut, dried, chopped and fed separately to sheep.
Supplementary feeding of forage to grazing dairy cows, 3. The effect of three daytime stocking rates on the performance of cows offered grass silage overnight
Authors: ROBERTS D. J. , LEAVER J. D.
Published: April 2006

Over a 24‐week period, three groups of dairy cows were continuously stocked at 8, 10 or 12 cows ha‐1 between morning and afternoon milkings, and overnight were housed and offered grass silage ad libitum. Due to a prolonged drought, sward heights only averaged 4·1 cm.

The increase in daytime stocking rate led to a decline in herbage intake, and increases in silage intake. At the highest stocking rate (12 cows ha‐1), the silage intake failed to compensate for the reduced herbage intake. Consequently the total dry matter and estimated metabolizable energy intakes were lower than for the 8 and 10 cows ha‐1 treatments. Milk yields and milk composition were not significantly affected by treatment but the 12 cows ha‐1 stocking rate gave the lowest milk and milk solids yields.

The utilized metabolizable energy (UME) on the grazed swards was greatest for the 10 cows ha‐1 treatment. The sward cut to provide the silage had a UME level (GJ ha‐1) 32% greater on average than the grazed swards during the same growth period. The total areas utilized for grazing and silage production for 8, 10 and 12 cows ha‐1 were 0·240, 0·224 and 0·215 ha respectively. Fat and protein yields per unit area were greatest for the 10 cows ha‐1 group.
Estimation of the ruminal degradation of forage rape after incubation in nylon bags in the rumen of sheep
Authors: DOVE H. , McCORMACK HEATHER A.
Published: April 2006

The nylon bag technique was used to measure the disappearance of dry matter, nitrogen and non–nitrogenous dry matter from samples of forage rape leaf and stem incubated in the rumen of sheep. Samples were either hand–harvested and chopped or obtained using Iambs with oesophageal fistulae.

Differences were observed in the dry matter and nitrogen contents of oesopha1 fistulae extrusa and cut samples; calculations are presented to suggest that these differences were not due to salivary contamination. Compared with cut samples, oesophageal fistulae extrusa had significantly higher initial disappearance, fractional rate of disappearance and predicted disappearance of both dry matter and nitrogen. Observed disappearances from leaf and stem extrusa after 24 h incubation were: dry matter from leaf 0·898 and from stem 0·832; nitrogen from leaf 0·942 and from stem 0·910. Corresponding values for cut leaf and stem were 0·817, 0·726, 0·883 and 0·849, respectively.

The rumen degradation of protein (nitrogen × 6·25) was computed for all combinations of leaf, stem, cut and extrusa samples for rumen fractional outflow rates ranging from 0·02 to 0·09. Degradation levels computed from cut samples were much less than those based on oesophageal fistulae extrusa and are suggested to be underestimates. Rumen degradation levels for forage rape leaf and stem were very similar and ranged from 0·83 to 0·75 over the above range of fractional outflow rates.
The effects of frequency of defoliation, date of first cut and heading date of a perennial ryegrass companion on the yield, quality and persistence of diploid and tetraploid broad red clover
Authors: SHELDRICK R. D. , LAVENDER R. H. , TEWSON V. J.
Published: April 2006

The effects of cutting frequency on dry matter yield, crop persistence and herbage quality of representative diploid and tetraploid varieties of broad red clover (Trifolium pratense) were investigated in two trials at Hurley in the period 1975–79.

Pure‐sown swards of broad red clover varieties were used in the first trial (A), while both pure‐sown swards and those sown with a perennial ryegrass companion grass were included in the second trial (B).

Tria1was cut three or six times per annum, trial B three, four or five times per annum. In both trials, the change from normal management of three cuts per annum to six (trial A) or five (trial B) cuts per annum reduced output, whether in terms of dry matter yield (trial A by 31%; trial B by 33%), N yield (trials A and B by 15%) or metabolizable energy (trial A by 24%; trial B by 28%), and in trial A also led to more rapid reduction in clover plant density. More frequent cutting also raised mean D–value (trial A by 5–3 units; trial B by 3–4 units) and N concentration (trial A by 64 g kg dry matter‐1; trial B by 70 g kg dry matter‐1). Tetraploid (4x) red clover varieties generally out–yielded diploid (2x) varieties, except in trial A in 1976 when, under drought conditions, Granta and Kuhn (both 2x) equalled the yield of Wensum (4x) and out–yielded Norseman and Maris Leda (both 4x).

The companion grasses included in trial B formed a sequence from early to late flowering (Aberystwyth S24, Barlenna, Endura), and their inclusion raised dry matter yields and D‐value, though it lowered N concentration in the mixed herbage. Highest annual dry matter yields in this trial, which received supplementary irrigation, were 1641 ha‐1 from a pure–sown crop (Hungaropoly) and 205 t ha‐1 from a mixture (Wensum/ Aberystwyth S24), from three cuts in the first harvest year. Aberystwyth S24 had the greatest effect in raising yields; though least effect on improving digestibility. Endura was the converse, and it was concluded that an intermediate‐maturity variety such as Barlenna was the most satisfactory companion.

Both trials A and B suggested that in south–east England, broad red clover can be considered only as a 2–year crop and that ways must be found to prolong its productive life. Strategies to increase the digestibility and hence the economic value of the crop by cutting more frequently than three times per year are unattractive because of the large fall in yield and relatively small improvement in digestibility and hence metabolizable energy concentration.
Further studies on the effect of phosphate fertilizer and propyzamide on the growth of white clover slot‐seeded into permanent pasture
Authors: WILLIAMS E. D.
Published: April 2006

Assessments were made of the clover yield and clover content between early June and late July 1984 of white clover in a permanent pasture which had been slot‐seeded in spring 1982.

Past reserves of phosphate or application of propyzamide alone only slightly increased clover dry matter yield but together they increased it from 13 to 785 kg dry matter ha‐1 and gave 31% clover in the total herbage yield. Applications of P2O5 during the experiment, alone or together with past reserves of phosphate, Iased clover yield from 13 to 242 kg dry matter ha‐1 and the proportion of clover from 1 to 10%. However, highest yields (1282 kg) and clover content (37%) were attained when P2O5 and propyzamide were applied to treatments with past reserves of phosphate.

These results confirmed the trends evident during the second year and also indicated a potential role for grass‐suppressants in increasing management options during the early years after slot‐seeding.
Influence of structure and composition of ryegrass and prairie grass‐white clover swards on the grazed horizon and diet harvested by sheep
Authors: L'HUILLIER P. J. , POPPI D. P. , FRASER T. J.
Published: April 2006

Diet selection from ryegass‐and prairie grass‐white clover swards, vertically stratified into three horizons (A > 6 cm, B 3–6 cm, C > 3 cm), was studied using oesophageally fistulated sheep during summer and autumn. Animals grazed for 3‐day periods. Apparent herbage intake was calculated from total herbage disappearance. The composition of each horizon and of the diet selected was measured daily.

Herbage mass (DM ha‐1) and sward height (cm) prior to grazing were not significantly different between swards in each season, and were 2·0 and 20 in summer and 1·6 and 10 in autumn. In summer, 36% and 5% of the green grass leaf (GGL) for prairie grass and ryegrass, respectively, was distributed in horizons A and B. In autumn 39% and 29% of GGL occurred above 3 cm for prairie grass and ryegrass, respectively. GGL distribution determined which sward horizons were grazed. Sheep grazed horizon C (0–3 cm) of summer ryegrass pasture, and the surface canopy (>3 cm) of all other swards.

In summer, apparent intake achieved by sheep grazing prairie grass swards was 87% higher than that achieved on ryegrass swards. In autumn a greater GGL distribution above 3 cm with prairie
The indirect estimation of the digestibility in cattle of herbage from Belgian permanent pasture
Authors: BARTIAUX‐Thill NICOLE , OGER ROBERT
Published: April 2006

Relationships between herbage organic matter digestibility measured in vivo, and faecal nitrogen concentration were determined. Measurements of in vivo digestibility were made on twenty‐nine herbages, cut from mixed improved permanent pastures with Lolium perenne as the predominant grass and offered ad libitum to cattle. The faecal nitrogen index predicted the herbage digestibility with good accuracy, and the equations obtained should have application for such determinations on Belgian pastures.
Study of the population dynamics of dipterous stem‐borer larvae of ryegrass swards under rotationally grazed or cut conditions
Authors: MOORE D. , CLEMENTS R. O.
Published: April 2006

Observations made between 1980 and 1982 showed that dipterous stem‐borers were more common in grazed than cut swards. The two forms of Oscinella frit were particularly prevalent in grazed swards but O. vastator was more evenly distributed and dominated the larval populations of the cut sward in 1981. The population dynamics of all species were probably affected by the number of days on which weather was suitable for high stem‐borer adult activity. It was also found that stem‐borer larval numbers could expand rapidly after periods suitable for high adult activity even when adult numbers had been low for long periods. Despite low numbers of O. vastator being present in winter 1981, their numbers increased markedly and built up to a large population which peaked in September 1981.
Predicting the response of perennial ryegrass to fertilizer nitrogen in relation to cutting interval, climate and soil
Authors: DOYLE C. J. , RIDOUT M. S. , MORRISON J. , EDWARDS C.
Published: April 2006

This paper describes the derivation of a series of equations for estimating mean grass production on cut swards under different fertilizer nitrogen, soil and climatic regimes. Using data from the National Grassland Manuring Trial GM20 for a late flowering perennial ryegrass, equations have been estimated for the individual cuts. On the basis of data from cutting trials at Hurley, equations for extrapolating yields under cutting strategies with different first cut dates and regrowth intervals have been derived. The resultant model for predicting yields has then been tested against data obtained from two separate cutting trials. Although in individual cases significant differences between predicted and observed mean yields were noticed, in general the predicted yields were a reasonable approximation to observed yields. Comparison of the predicted yields with those derived from an earlier study by the authors indicated an improvement in the accuracy of prediction.
The influence of the system of silage harvesting and feeding and the use of protected protein on milk production
Authors: GORDON F. J.
Published: April 2006

The study compared two systems of silage harvesting, direct‐cutting flail harvesting (flail‐direct) or pre‐cutting, followed by wilting and collection by a meter‐chop harvester (precision‐wilted). Each silage was self or easy fed to dairy cows. In addition, the response to protected soya bean meal included in the supplementary concentrate was also examined.

Approximately 400 t of each of the two silages were produced from the same swards under good weather conditions with formic acid applied as an additive. The resulting silages were well preserved and had mean particle lengths of 43 and 29‐mm, and D‐values of 0‐74 and 0‐71 for the flail‐direct and precision‐wilted silages, respectively.

During a 159‐d feeding period commencing on 5 November, the silages were offered to 88 British Friesian cows in a 23 factorial design, continuous feeding experiment. The cows calved during the experiment and had a mean calving date of 18 January. The feeding treatments involved both silage types, two systems of silage feeding (self and easy) and two sources of protein in the supplementary concentrate given after calving (soya bean or 100 g kg‐1 protected soya bean). No concentrates were offered pre‐calving and all animals were given 7.6 kg d‐1 concentrates post‐calving.

There were no significant interactions between the system of silage harvesting and feeding.

Animals on the precision‐wilted silage consumed 14% more silage dry matter (10.9 vs. 9.6 kg DM d‐1) over the total period and by the end of the experiment were producing 7% less milk per day (25.4 vs. 27.2 kg). However, the responses in the output of total milk constituents (fat and protein) were lower than those obtained in milk yield. Animals offered silage by self feeding had similar dry matter intakes, but produced marginally less milk than those easy‐fed.

Ration digestibility and nitrogen utilization data, obtained from a concurrent change‐over design experiment, suggested that the energy from the precision‐wilted silage was less efficiently utilized for milk production.

There was no significant response in either milk yield or composition to the inclusion of protected soya bean in the supplement.
Comparative studies of ingestive behaviour and diet composition in oesophageal‐fistulated and non‐fistulated cows and sheep
Authors: FORBES T. D. A. , BEATTIE M. M.
Published: April 2006

A series of comparisons was made of the bite rates of fistulated and non‐fistulated cattle and sheep, grazing four grassy hill plant communities over four years. Both bite rates and grazing times were recorded on two occasions. Comparative observations were also made on faecal cuticle concentrations on one grassy and one dwarf shrub community and on faecal ash, nitrogen (N) and acid detergent fibre (ADF) concentrations throughout one year.

Faecal N concentrations were slightly but consistently higher in fistulates than in non‐fistulates, but faecal ADF and ash concentrations and the relative proportions of faecal cuticle fragments were similar and did not indicate differences in either diet composition or digestive efficiency. Bite rates did not differ significantly between fistulates and non‐fistulates, except on the two occasions when fistulates carried Vibracorders to measure grazing time without preliminary training, and grazing times did not differ significantly. There were significant differences between cattle and sheep in most variables.

On the basis of this evidence, there is no reason to expect that fistulated and non‐fistulated animals of similar history and nutritional background will differ in grazing behaviour or diet composition.
A study of the potential of lucerne as a silage crop in a high‐rainfall area
Authors: REID D.
Published: April 2006

The results are reported of a 2‐year plot experiment investigating the potential of lucerne as a silage crop in a comparatively high‐rainfall area (annual average of about 900 mm). The performance of the lucerne on the remainder of the field in which the plot experiment was located is also discussed. With below‐average rainfall in the sowing year a good establishment was obtained and a single cut to a stubble height of 75 mm in August gave a dry matter yield of 3 t ha‐1. In the first harvest year, summer rainfall was again below average and a total dry matter yield of 13·8 t ha‐1 resulted from three cuts to 75 mm above ground level. However, the total yield was reduced to 10·11 ha‐1 in the second year when the rainfall was considerably above average. Attempts to increase the feeding value of the lucerne herbage by increasing cutting frequency and by increasing cutting height showed little effect over the standard system of three cuts to a stubble height of 75 mm. The effects of applying potassium fertilizer at rates supplying 100,200 or 300 kg K ha‐1 either as a single spring dressing or in equally divided dressings were not significant in either of the two years
The influence of ethofumesate on the growth and development, chlorophyll and nitrogen content of Lolium perenne L.
Authors: DEAN M. R. , OLLERENSHAW J. H. , STEWART W. S.
Published: April 2006

Pot experiments and a hand‐weeded field trial were carried out to investigate the direct effect of ethofumesate on the growth and development of Lolium perenne cv. S24.

In the field trial, ethofumesate was applied in autumn as Nortron 20% ec formulation in a volume of 2001 ha‐1 at rates of 0, 1 or 2 kg a.i. ha‐1. Treatments had no direct effect on yield in the following summer. In both the field trial and pot experiments there was initial growth suppression in the form of a reduction in shoot dry weight, lamina dry weight, tiller number per plant and plant height. However, ethofumesate increased the chlorophyll and nitrogen contents of L. perenne laminae, but only when available soil nitrogen was not limited.

It is concluded that ethofumesate can increase the yield of L. perenne by suppressing weed competition, but there is no evidence of the herbicide directly increasing the growth or yield of cv. S24.
The potential of an all‐grass diet for the late‐winter calving dairy cow
Authors: RAE R. C. , THOMAS C. , REEVE A. , GOLIGHTLY A. J. , HODSON R. G. , BAKER R. D.
Published: April 2006

In a trial lasting 3 years at Jealott's Hill and 2 years at Ravenscroft Hall, a total of 73 January‐ March‐calving Friesian x Holstein cows and heifers were given a diet consisting almost exclusively of ensiled and grazed ryegrass for an entire lactation to establish the level of milk production which grass alone can support. From calving to turnout in April/May (average duration 87 days), the animals were given high digestibility (DOMD = 678g kg‐1 DM) ryegrass silage ad libitum. After turnout, they grazed ryegrass swards until housing in autumn. Thereafter, the cattle were given ryegrass silage of lower digestibility (DOMD = 600–620 g kg‐1 DM) for the remainder of the lactation and during the dry period.

Mean silage dry matter intakes from calving to turnout were 13–2 kg day‐1 at Jealott's Hill and 11·5 kg day‐1 at Ravenscroft Hall. Average milk yields were 21‐1 kg day‐1 for cows and 16‐1 kg day‐1 for heifers with 39‐2g fat kg‐1, 29‐6g protein kg‐1 and 47–9 g lactose kg‐1. Over the complete lactation, average milk yields were 4680 kg and 4006 kg for the cows and heifers, respectively, with 39‐4 g fat kg‐1, 31·4 g protein kg‐1 and 46·9 g lactose kg‐1. Animal health and fertility were satisfactory. The results demonstrated the value of high quality grazed and ensiled ryegrass and provided a measure of milk production from grass only.
The effects of feeding fodder beet to dairy cows offered silage ad libitum
Authors: ROBERTS D. J.
Published: April 2006

In a 16‐week winter feeding experiment, 48 autumn calving cows and heifers were used to compare a control diet, with two diets including fodder beet at a low and a high level. The control diet was ad libitum silage and 6 kg d‐1 of concentrates (13.4 MJ (kg DM)‐1 of ME and 197 g (kg DM)‐1 of CP). The cows offered fodder beet were fed the control diet (C) plus fodder beet at either 2 (L) or 4 (H) kg DM d‐1. Soya bean meal was offered with the fodder beet at 0.5 or 1.0 kg d‐1 for diets L and H, respectively.

Total dry matter and metabolizable energy intakes were 15.2,16.4 and 17.3 kg DM d‐1; 177, 195 and 211 MJ d‐1 for treatments C, L and H, respectively. The mean milk yields were not significantly affected by the feeding of fodder beet. There was a significant improvement in the fat and protein content of the milk and yield of constituents. The milk composition and yield of solids were: fat content 42.3,44.2 and 45.9 (s.e.d. 1.25) g kg‐1; protein content 33.0, 34.5, 35.3 (s.e.d. 0.76) g kg‐1; fat yield 964,1027,1095(s.e.d. 63.2); protein yield 757, 801, 841 (s.e.d. 48.8) for treatments C, L and H, respectively. The treatments had no significant effect on live weight or condition score change.
Herbage potassium levels in a permanent pasture under grazing
Authors: TALLOWIN J. R. B. , BROOKMAN S. K. E.
Published: April 2006

Herbage potassium levels were measured in 1986 in a permanent pasture under continuous grazing with cattle and receiving 200 kg N ha−1. In April, before grazing started, K concentration in the herbage was relatively uniform across the pasture, with a value of 1·9 ± 0·038% K in the herbage dry matter. In July, a significantly lower concentration of herbage K was found in the grazed areas of the pasture (1·8 ± 0·10%) compared with the level (2·4 ± 0·088%) found in the rejected areas of the sward. The difference between the grazed and rejected areas was similar in September, with 1·6 ± 0·087% and 2·2 ± 0·172% K, respectively, in the herbage dry matter. This result suggests that herbage growth in the grazed areas might have been limited by K supply and highlights the need for more information on the K requirements of grazed grassland.
Harvest frequency effects on forage yield and quality of rapes and rape hybrids*
Authors: JUNG G. A. , SHAFFER J. A. , STOUT W. L. , PANCIERA M. T.
Published: April 2006

Spring‐seeded rape requires approximately two‐thirds of the growing season in the north‐cast USA, to reach physiological maturity. Harvest frequency studies were conducted with rapes and rape hybrids in Pennsylvania to determine whether forage yields and/or quality can be improved with multiple harvests, and whether cultivars respond similarly to harvest management. Nitrogen was applied at 75 kg ha−1 at seeding and 75 kg ha−1 70 d after seeding. Additional fertilizer was applied according to soil test results. A split‐split‐block design was used. Harvest frequencies of 180, 90, 60, or 30 d were randomly assigned to blocks. Cultivars were randomized within each harvest frequency, with four replicates. Amount of regrowth of all cultivars after mid‐August was highly variable, depending on weather. Foliar diseases and aphids lowered yields in different years. Cultivars differed in susceptibility to diseases and aphids as well as in morphology. Forage yields and crude protein yields of rape generally were highest with the 90‐d harvest frequency, whereas crude protein concentration was highest with the 30‐d frequency. Mean in vitro dry matter digestibility (IVDMD) values were high regardless of harvest frequency, cuttivar, or sampling date. Yield differences between cultivars generally were greatest with one harvest at 180 d; mean yield was highest for forage rapes, intermediate for winter oil rapes, and lowest for rape x Chinese cabbage hybrids. Under frequent harvesting, BLE rape and the rape x Chinese cabbage hybrid performances were exceptional as regards forage yield and quality.
Use of a model to optimize the interaction between frequency and severity of intermittent defoliation and to provide a fundamental comparison of the continuous and intermittent defoliation of grass
Authors: PARSONS A. J. , JOHNSON I. R. , HARVEY A.
Published: April 2006

A previously described model of grass growth was used to analyse the effect of the severity of defoliation and the duration of the subsequent regrowth on the overall balance between photosynthesis, gross tissue production and leaf death and so on the amount that could be harvested/consumed per hectare under intermittent defoliation. Maximum yield per hectare was shown to be achieved whenever the fluctuations in LAI during regrowth and defoliation led lo the same low average LAI that was previously shown to give maximum yield (amount harvested/consumed per hectare) under continuous grazing. Thus, it is suggested that production under both continuous and intermittent defoliation may best be characterized, and diverse managements may be rationalized, on the basis of the average sward state, the average achieved. The analysis leads us to reconsider some widely held concepts of the growth and utilization of grass applied in both agronomic and ecological theory, and the provision of practical guidelines for management.
Herbage growth and utilized output from grassland on dairy farms in southwest England: case studies of five farms, 1982 and 1983. II. Herbage utilization
Authors: PEEL S. , MATKIN ELIZABETH A. , HUCKLE C. A.
Published: April 2006

Utilized Metabolizable Energy output was calculated and herbage utilization evaluated in two contrasting years on five profitable farms representing a range of soil types.

Annual UME output was 72 GJ ha‐1 on average, with a range from 47 to 91 GJ ha‐1. Grazed grass provided 66% of the utilized metabolizable energy, and conserved grass 34%. Higher utilized metabolizable energy output was not always obtained at higher fertilizer N inputs, even when soil moisture conditions favoured herbage growth.

The efficiency of utilization of herbage conserved (almost always as silage rather than hay) was calculated by expressing utilized metabolizable energy output as a proportion of the quantity of herbage cut, measured by swath weighings; the mean value was 64%, with a range from 55 to 73%. Cellulose analyses indicated that mean dry matter losses via CO2 and effluent were 10%; the remaining 26% loss appeared to be due to physical losses in the field, surface waste and wastage at feedout.

For grazed herbage the utilized metabolizable energy output was expressed as a proportion of herbage accumulation measured over 28‐day periods. The resultant apparent efficiency of utilization averaged 67%, with a wide range from 51 to 83%. The lowest values were on badly drained farms.

It is suggested that:

(i) there is considerable potential for increasing output from grazing on dairy farms; higher grazing pressure and more flexible management would be needed. Targets should probably be set lower on badly drained soils;

(ii) there is great potential for increasing the efficiency of utilization of conserved forage, by careful application of existing technology;

(iii) on the farms studied the utilized metabolizable energy output from grazed and conserved fields appeared to be similar.
Effect of anhydrous ammonia treatment on the chemical composition and nutritive value of grass hay and on intake and performance in beef steers
Authors: WYLIE A. R. G. , STEEN R. W. J.
Published: April 2006

Two compositionally similar, mature grass hays, of dry matter contents 699 and 836 g kg‐1, were treated with anhydrous ammonia at levels of 10, 20 and 30 kg NH3 t DM‐1 and 20, 30 and 40 kg NH31 DM‐1, respectively. Treatment at 10 kg t‐1 did not inhibit moulding of the damp hay. The remaining treatments increased the nitrogen contents of damp and dry hay, respectively, from 12.5 and 13.8 g kg DM‐1 to maxima of 250 and 270 g kg DM‐1 and the water‐soluble ammonia‐nitrogen contents of oven‐dried samples from 24 and 23 g kg‐1 to maxima of 118 and 88 g kg‐1 of total nitrogen. While all treated hays had reduced levels of insoluble hemicellulose, ammoniation increased the insoluble cellulose content of damp hay only.

In trials of 37 and 80 days duration, respectively, the untreated and 20 and 30 kg t‐1‘damp'‐ammoniated hays and the untreated and 20, 30 and 40 kg t‐1‘dry'‐ammoniated hays were offered ad libitum, unsupplemented or supplemented with 2 kg d‐1 of a barley‐soya compound, to steers of 328 kg and 383 kg mean initial liveweight. Steers offered untreated and 20 and 30 kg t‐1 ammoniated damp hays and untreated and 20, 30 and 40 kg t‐1 ammoniated dry hays, all ad libitum and alone, consumed 5.50, 6.48 and 6.59 and 6.78, 782, 790 and 8.26 kg d‐1 and gained 471,560 and 521 g d‐1 and 490,699,794 and 572 g d‐1, respectively. When supplemented, the same hays, again offered ad libitum, produced live‐weight gains of 529, 515 and 736 g d‐1 and 725, 705,726 and 895 g d‐1, respectively. The apparent in vivo digestibilities of hay dry matter, organic matter, gross energy, hemiceliulose, cellulose and nitrogen were significantly increased by ammoniation.