bluuebunny/crossref_metadata_2025_split huggingface dataset:
A comparison of methods of establishing perennial and Italian ryegrasses
Authors: BARTHOLOMEW P. W. , EASSON D. L. , CHESTNUTT D. M. B. 
Published: April 2006

AbstractAn experiment extending over a 2½‐year period from June 1976 to October 1978 assessed the effect on herbage yield of method of establishment, species and level of N application.Perennial ryegrass cv. Gremie and Italian ryegrass cv. RvP were established by broadcasting or drilling into cultivated ground or by direct‐drilling, using a Howard Rotaseeder, into paraquat‐sprayed but uncultivated ground. These treatments were combined with annual rates of N application of 0, 120, 240 or 360 kg ha‐1.Over the experiment drilling into cultivated ground gave the highest yield—3·6 and 4·8% higher than the broadcast and direct‐drilled treatments, respectively. Italian ryegrass consistently outyielded perennial ryegrass, with an overall mean dry matter yield advantage of 23·7%. There was no significant interaction between sowing method and species; direct‐drilled Italian ryegrass produced a mean yield 17·3% higher than that of drilled perennial ryegrass.
The development and use of equipment for the automatic recording of ingestive behaviour in sheep and cattle
Authors: CHAMBERS A. R. M. , HODGSON J. , MILNE J. A. 
Published: April 2006

AbstractA description is given of equipment designed to be fitted to either sheep or cattle, and to record automatically information on the jaw movements associated with both grazing and ruminating, movements of the head in plucking mouthfuls of herbage, and the time spent in grazing. The equipment has been successfully tested against alternative visual and mechanical methods of measuring grazing behaviour.The use of modified equipment in detailed studies has shown (a) that the maximum acceleration of the head in a longitudinal plane when plucking mouthfuls of herbage was twice as great in sheep as in cattle and in the sheep, but not in the cow, increased as sward height decreased; and (b) that the ratio of jaw movements to head movements was always greater than unity in both sheep and cattle, and was greater on tall than on short swards in two out of three comparisons. The rate of biting was significantly lower on tall than on short swards.
Observations on the effect of post‐emergence application of ethofumesate on the shoot growth of Poa annua and Lolium perenne seedlings†
Authors: JUKES A.M. , GOODE P.M. 
Published: April 2006

AbstractSwards of L. perenne and P. annua were treated at the 2–3 leaf stage with recommended rates of ethofumesate (5 and 10 kg a.i. ha‐1). P. annua ceased normal growth, became swollen at the shoot base and eventually showed signs of senescence. L. perenne showed no visible defects, treated swards being more vigorous than untreated. Scanning electron micrographs showed that the developing leaf primordia of P. annua had been affected by the ethofumesate. In both grass species, ethofumesate induced abnormalities in cell division. These abnormalities caused irreversible damage to P. annua but only slight distortion of L. perenne which later recovered and resumed normal growth. More detailed biochemical studies are required to determine the specific effects of ethofumesate on cell growth.
Herbage intake and milk production by grazing dairy cows. 3. The effect of grazing severity under continuous stocking
Authors: LE DU Y. L. P. , BAKER R. D. , NEWBERRY R. D. 
Published: April 2006

AbstractThe effects of severity of grazing on the herbage intake and milk production of continuously stocked British Friesian cows calving in February–March were examined in three experiments conducted in the years 1976–78 (experiments 1–3 respectively) using a put‐and‐take technique. In experiment 1 four grazing severities were imposed by maintaining swards with different herbage masses (2500, 3000, 3500, 4000 kg OM ha‐1); in experiments 2 and 3 there were two severities of grazing maintained by keeping swards canopies at constant heights of 5 and 7 cm (experiment 2) and 5 and 7·2 cm (experiment 3). Cows were reallocated to treatment every 8 weeks in experiments 1 and 2 and there were three periods, whereas they all grazed throughout a 23‐week period on the same treatment in the final trial.A decrease in the quantity of herbage on offer or in sward height reduced herbage intake and milk production in all experiments. Mean daily herbage OM intakes were 11·2, 12·2, 12·2 and 12·2 kg respectively in experiment 1, 12·2 and 13·2 kg respectively in experiment 2 and 12·2 and 152 kg respectively in experiment 3. Mean daily solids–corrected milk yields were 14·2, 15·2, 15·2 and 16·2 kg respectively in experiment 1, 14·2 and 16·2 kg respectively in experiment 2 and 12·2 and 17·2 kg respectively in experiment 3. It was apparent from the data obtained in the first two trials that grazing at a sward canopy height of 7 rather than 9 cm had little effect, but that at 5 cm there were significant depressions in both herbage intake and milk production. Milk yield was depressed to a greater extent when cows were kept on the same treatment for the whole season.
The effects of clover variety, cutting interval and nitrogen application on herbage yields, proportions and heights in perennial ryegrass‐white clover swards
Authors: WILMAN D. , ASIEGBU J. E. 
Published: April 2006

AbstractSix varieties of white clover, each grown with perennial ryegrass, four intervals between cuts and two levels of applied nitrogen in all combinations, were compared in a field experiment during the first 27 months after sowing.Increasing the interval between harvests from 3 or 4 to 8–12 weeks increased the yield of white clover and generally did not reduce the proportion of clover in total herbage. Increasing the interval between harvests reduced the number of grass tillers but increased grass yield and the size of grass leaves and increased grass height more than clover height; it also increased the proportion of petiole relative to leaflet in the clover. Differences between varieties in response to interval between harvests were small but supported the view that medium large‐leaved varieties can with advantage be defoliated rather less frequently than small‐leaved ones. The adverse effect of applied N on clover appeared almost equally great with all four intervals between harvests and further research on this topic is suggested. Applied N increased grass height more than clover height and increased the number of grass tillers, the size of grass leaves and grass yield. The medium large‐leaved varieties seemed more tolerant of applied N than the smaller varieties.
The effects of pesticide application on upland permanent pasture
Authors: CLEMENTS R. O. , HENDERSON I. F. , BENTLEY B. R. 
Published: April 2006

AbstractAn estimate of the level of pest damage on enclosed upland permanent pasture in England and Wales was made by reducing invertebrate populations with insecticides at thirteen well‐distributed sites and measuring the effect on herbage growth over a 3‐year period. Potential pests were fewer in number than on lowland pastures and there was a wide range in herbage yield between sites. Insecticide treatment significantly increased annual yields at only three of the sites, and significantly decreased yield at two of the sites. Insect damage to grassland appears to be much less important in upland than in lowland areas: this may be due to the relative scarcity of frit‐fly in these areas, but this could change if its preferred host, ryegrass, were encouraged by intensification of sward management in the uplands. At all but one of the sites insecticide treatment led to considerable soil compaction, probably as a consequence of suppressing earthworm populations.
Silage and milk production: comparisons between hays of different digestibilities as silage supplements
Authors: RETTER W. C. , CASTLE M. E. 
Published: April 2006

AbstractIn three separate feeding experiments using a total of thirty individually‐housed Ayrshire cows three silages made from perennial ryegrass were given ad libitum together with supplements of four different hays in the long form. The in vitro D‐values of the silages ranged from 0·298 to 0·283, and the hays from 0·280 to 0·200. The daily intake of hay DM varied from 0·2 to 4·2 kg per cow and was given either without or with a daily maximum of 2·2 kg concentrate DM containing 379–527 g CP per kg DM. On average, 1 kg hay DM decreased silage intake by 0·24 kg DM with a range of 0·21–1·20 kg. The hay supplements had only small and non‐significant effects on total DM intake, milk yield and milk composition, but increased the daily intake of drinking water. In three behavioural studies, the eating and ruminating times expressed as min per kg DM did not differ significantly between the various supplement treatments. It is concluded that hay has only a marginal value as a supplement for grass silage, although the hay could serve as a useful ‘buffer’ feed if the amount of silage was limited.
The pattern of growth in swards of two contrasting varieties of white clover in winter and spring
Authors: DAVIES ALISON , EVANS M. ELEANOR 
Published: April 2006

AbstractIn a study of growth rates and developmental morphology of simulated swards of two contrasting white clover varieties, Katrina and Kent, it was found that both varieties continued to produce dry matter throughout the winter at Aberystwyth. The gross crop growth rate in the coldest periods was about 7 kg ha‐1 d‐1. The rates of formation and loss of new leaves were approximately equal so that there was no net increase in weight until the latter part of March. This initial net weight increase in both varieties was observed in the same harvest interval, the most important factor being the difference in weight between the new leaf plus petiole unit and the weight of the unit which it replaced. The weight of laminae and petioles throughout the experiment was somewhat higher in Katrina which has come to be regarded as the ‘earlier’ variety.The prospects for improving spring production in white clover by variety improvement are discussed.
The preharvest use of glyphosate in the ryegrass seed crop
Authors: HAMPTON J. G. , HEBBLETHWAITE P. D. 
Published: April 2006

AbstractPreharvest application of 1 and 2 litres ha‐1 IPA glyphosate (glyphosate) to a seed crop of S24 perennial ryegrass with moisture concentrations of around 400 and 340 g kg‐1 (40 and 34% moisture content w/w) failed to significantly lower seed and straw moisture concentration at harvest and consequently did not affect combine rate. Addition of extra surfactants and ammonium sulphate to glyphosate did not significantly increase the rate of desiccation.The quality of harvested seed was impaired at both rates and application times. Germination was significantly lowered through the production of abnormal seedlings. The germination of seed harvested in the previous year from glyphosatetreated plots decreased with storage. Seed vigour, germination rate and field emergence were also significantly decreased as a result of glyphosate application. The effect of glyphosate on seed quality precludes its preharvest use as a desiccant in the ryegrass seed crop.Harvesting difficulties due to the production of secondary vegetative tillers may be overcome by swathing rather than direct combining.
A technique for estimating rate of disappearance of dead herbage in pasture
Authors: YATES J. J. 
Published: April 2006

AbstractA technique for estimating the rate of disappearance of material from samples of dead herbage protected by simple nylon or wire mesh covers is described. Using this technique on a perennial ryegrass sward in southern England during August‐November, relative rates of disappearance close to 0·204 g g‐1 d‐1 (DM) were obtained, but the variability was high. When herbage killed with paraquat was used, the rate of disappearance was higher and the variability lower. There were only small differences in the temperatures recorded in a normal sward and within samples of dead herbage under mesh covers.
Root size estimates of red clover and alfalfa based on electrical capacitance and root diameter measurements
Authors: KENDALL W. A. , PEDERSON G. A. , HILL R. R. 
Published: April 2006

AbstractElectrical capacitance and root diameter techniques for estimating root dry weight were evaluated in one test with red clover plants grown on slant‐boards in plant growth chambers for 37–77 d, and in six tests with alfalfa grown in the field for 55–165 d. Root dry weights of red clover were estimated satisfactorily with regression equations from both diameter (R2=90%) and capacitance (R2=76%) measurements. Root dry weights of alfalfa were estimated satisfactorily throughout the entire season from diameter values (R2 from 51 to 92%). Alfalfa root weight was significantly (P <0·25) related to capacitance values at the beginning and at the end of the season but not at mid‐season. Electrical capacitance measurements were similar for intact root systems and roots severed 4 cm below the crown in separate experiments with red clover and with alfalfa. The root diameter technique provided an accurate, rapid and inexpensive method of estimating root size throughout the first season of growth. The root capacitance method provided satisfactory estimates of roots at certain times during the summer. Neither method would be useful if a large portion of the root was naturally severed.
A statistical assessment of the dry‐weight‐rank method of pasture sampling
Authors: SANDLAND R. L. , ALEXANDER J. C. , HAYDOCK K. P. 
Published: April 2006

AbstractThe statistical properties and applicability of the Dry‐Weight‐Rank (DWR) method of pasture sampling are examined. Formulae for the expected value and variance of the DWR estimates are presented.The extent of bias in DWR is examined using several mathematical models. DWR is shown to break down when estimating multinomial proportions; however it provides good estimates for a subset of models simulated from a class of compound probability distributions.The success of DWR in practice does not rest on a theoretical basis. It appears to be a remarkable empirical discovery that DWR estimates are virtually unbiased on most pasture types. Several cases are considered where difficulties may be encountered in using DWR. Provided the theoretical reservations of this paper are borne in mind, DWR will continue to be a useful practical tool, especially in the absence of non‐destructive observational alternatives.
Grass height as an indicator for supplementary feeding of continuously stocked dairy cows
Authors: LEAVER J. D. 
Published: April 2006

AbstractThree groups of cows were continuously stocked on pasture and offered supplementary concentrates according to the herbage height measured weekly with a grass disc. Concentrates were offered when the mean herbage height fell below 9 cm for treatment A, 7 cm for treatment B and 5 cm for treatment C at a rate of 1 kg d‐1 for each 0·2‐cm decline below these threshold levels. If the herbage height declined by more than 1·2 cm (8 kg concentrates d‐1) hay was offered in addition ad libitum. The stocking rates for all three treatments were 5·2, 3·2 and 3·2 cows ha‐1 for three successive 8‐week periods. For treatments A, B and C the mean concentrate DM intakes were 3·2, 1·2 and 1·2 kg d‐1 (treatment A also received 0·2 kg hay DM d‐1), and the mean daily milk yields were 17·2, 16·2 and 15·2 kg respectively. The increasing level of supplementary feeding from treatment C to A also resulted in an increase in liveweight and body condition score change, and a reduction in milk fat.
Effects of season and level of grazing on the utilization of heather by sheep. 3. Longer‐term responses and sward recovery
Authors: GRANT SHEILA A. , MILNE J. A. , BARTHRAM G. T. , SOUTER W. G. 
Published: April 2006

AbstractThe effects of sheep grazing on the development of and production from heather swards and on intake and diet selection by grazing Scottish Blackface wether sheep were studied in an experiment in which sheep numbers were adjusted to remove 0, 40% or 80% by weight of current season's shoots in summer and in autumn for a period of 5 years. All combinations of season and level of grazing were provided. The plots were divided after 2 years and grazing was continued for a further 3 years on one subplot but discontinued on the other.Sward productivity during the 5 years of grazing was unaffected at the 40% level of shoot removal but at the 80% level was reduced by up to 66%.After a season's uninterrupted growth at the end of the experiment heather cover and herbage mass were lower and current season's shoots as a proportion of total mass were higher on those treatments which received the greatest severity of grazing. Weight of current season's shoots was unaffected on treatments which had received the 40% level of shoot removal but was reduced by 40% and 50% on treatments which had received the 80% level in summer and autumn respectively. On the rested subplots sward recovery was such that no treatment effects remained after 3 years except with respect to 80% shoot removal in autumn where herbage mass was reduced compared with other treatments.Intakes of digestible organic matter per sheep were higher at the 80% than the 40% level of grazing in the fifth year of the experiment. This was ascribed to the ingestion of new shoot growth from the twig bases on the 80% level of removal treatments. Intake and digestibility were higher in the summer on those treatments which had received the 80% level of removal in previous autumns. Over the 5 years of the experiment there was a small decline in intake and digestibility values, with the decline being greatest in the summer and at low levels of grazing.Floristic changes differed on the rested and grazed areas. On the rested subplots in the fourth year after grazing stopped, heather height was lower and cover by grasses, sedges and herbs was greater on treatments which previously had received the highest levels of utilization. On bare areas the rate of recovery of heather was rapid where shoots as well as seedlings contributed to recovery growth. On the grazed subplots, with the exception of the low‐growing ruderal Rumex acetosella, cover due to grasses, sedges and herbs remained low as species other than heather were selectively grazed.Relationships among stocking rates, grazing behaviour and heather utilization are discussed and guidelines for the recognition of overgrazing are outlined.
Sodium, potassium and calcium concentrations in varieties of Dactylis glomerata
Authors: MÍKA V. 
Published: April 2006

AbstractTwelve varieties of cocksfoot, Dactylis glomerata L., were analysed for three mineral elements (Na, K, Ca) and their dry matter (DM) yields were measured in pot and field trials. Among these characteristics there were strong varietal differences in Na concentration, whereas in other cases the varietal differences were less significant. The concentrations of individual mineral elements were, in most cases, independent of yield and of one another.Parent plants and their clonal derivatives were highly correlated in Na and Ca concentration as well as in DM yield. Tiller size or position on the parental plant had no significant effects on the mineral concentrations or DM yields of clones derived from separated tillers.Within varieties continuous variation was observed for Na concentration and the range of variation increased with increasing mean Na concentration. When plants were grown under different experimental conditions there was a high repeatability in Na concentration within varieties over cuts and years. This result was taken as an indication of a strong genetic basis for Na concentration. The results obtained in this study show that it is possible to develop grass varieties of defined potential Na concentration.
Silage and milk production: a comparison between three rates of high‐protein concentrate supplementation of grass silages of two digestibilities
Authors: CASTLE M. E. , GILL M. S. , WATSON J. N. 
Published: April 2006

AbstractGrass silages made from first‐harvest perennial ryegrass in mid‐May and early‐June and termed high‐D and low‐D respectively had mean DOMD values of 694 and 633 g kg−1 and were offered ad libitum to twelve Ayrshire cows in a 16‐week feeding experiment using a cyclic changeover design. The silages were supplemented with a concentrate containing 363g CP per kg DM at daily rates of 1.5, 3.0 and 4.5 kg per cow. The average daily intakes of silage DM were 12.6 and 11.1 kg per cow on the high‐ and low‐D silage treatments respectively, and were not significantly different on the three concentrate treatments. The mean daily milk yields were 171, 18.6 and 21.0 kg per cow on the low‐D silage treatments, and 19.6, 21.2 and 22.8 kg per cow on the high‐D silage treatments at the 1.5, 3.0 and 4.5 kg rates of concentrate feeding respectively. Fat and lactose concentrations in the milk were not affected significantly by treatment, whereas the CP and SNF concentrations increased progressively and significantly as the rate of supplementary feeding increased. It is concluded that a high‐protein concentrate supplement allows silage to make the maximum contribution in the diet, and gives a high response in terms of milk yield and composition.
Concentrate supplementation of grazing dairy cows
Authors: MEIJS J. A. C. , HOEKSTRA J. A. 
Published: April 2006

AbstractTwo experiments are described in which twenty‐four spring‐calving Dutch Friesian cows were allocated between six grazing treatments (two levels of daily herbage allowance × three levels of daily concentrate intake) in a 2 × 3 factorial design. The swards consisted predominantly of perennial ryegrass. A two‐machine sward‐cutting technique (with correction for herbage accumulation during grazing) was used for estimating herbage intake by cows which grazed swards for 3 or 4d. Experiment 1 was carried out for 16 weeks of the grazing season of 1981 and experiment 2 for 18 weeks in 1982.Daily herbage OM allowances in both experiments were 16 and 24 kg per cow above 4 cm cutting height. Daily concentrate OM intake ranged from 0.8 to 5.6 kg per cow. The effect of concentrates on herbage intake differed significantly between allowances. At the low allowance level and at daily concentrate OM intakes of 0.8, 3.2 and 5.6 kg per cow daily herbage OM intake was 10.9, 10.6 and 10.4 kg per cow respectively and the mean substitution rate of herbage by concentrates was only 0.1. At the high allowance level and at daily concentrate OM intakes of 0.8, 3.2 and 5.6 kg per cow daily herbage OM intake was 14.8, 13.6 and 12.4 kg per cow respectively and mean substitution rate was 0.5 kg herbage OM (kg concentrate OM)−1.
Dry matter and quality of herbage harvested from Holcus lanatus and Lolium perenne grown in monocultures and in mixtures
Authors: HARVEY B. M. R. , CROTHERS S. H. , HAYES P. 
Published: April 2006

AbstractThe herbage dry matter (DM) harvested, N response and herbage quality of monocultures and mixtures of Holcus lanatus (local ecotype) and Lolium perenne (cv. S24) were compared in a field experiment. The species were seeded in the proportions 100:0, 75:25, 50:50, 25:75 and 0: 100; three rates of N were applied (150, 300 and 450 kg ha−1) and five or six cuts were taken in each of four harvest years. H. lanatus established poorly in the seeding year and in the first full harvest year L. perenne contributed 1, 54, 76, 89 and 99% of the total herbage DM harvested from the five sward types (mean of N treatments). Only a small decline in the L. perenne content of the swards occurred during the experiment.Total amounts of herbage harvested were significantly lower for H. lanatus monoculture than for the other sward types in three of the four harvest years However, L perenne monoculture yielded significantly more total DM than mixtures with H lanatus in only one of the four harvest years. The five sward types did not differ overall in response to N fertilization. Nitrogen, phosphate and potassium content of the herbage was greatest for H. lanatus monoculture and decreased with increasing proportions ofL perenne present in the mixtures.Thus the presence of a high proportion of H. lanatus in mixture with L. perenne cv. S24 had