bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of time of sowing and sowing method on production of white clover in mixed swards
Authors: LAIDLAW A. S. , McBRIDE JAN 
Published: April 2006

AbstractTwo field trials were carried out in successive years in which (1) perennial ryegrass and white clover seeds were drilled together, or (2) clover was broadcast and grass drilled, or (3) both clover and grass were broadcast. The last two treatments were followed by harrowing or not of the seed bed. Sowing took place in early May or August. Four harvests were taken in each full harvest year.In establishment years, sowing in May resulted in a total dry matter (DM) production at least ten times higher than that resulting from sowing in August. No sowing method treatment effects on total DM or clover yield were significant in the establishment year (measured only in spring‐sown plots). In the first harvest year the August‐sown treatments produced 15% less DM than those sown in May and clover yield was, on average, 40% lower than the earlier sown treatments; clover proportion followed a similar pattern to yield.Drilling of both grass and clover without harrowing produced swards with a significantly lower proportion of clover in the first harvest year in the first trial than in treatments in which clover was broadcast but not harrowed. In the second trial at harvest 1, clover proportion just failed to be significantly lower in the treatment in which grass and clover were drilled than in the treatment when clover was broadcast and the seed bed harrowed.In the second harvest year (first trial only), annual clover yield and proportion were not affected but drilled grass and clover had lower DM yield than when grass was drilled and clover broadcast without harrowing and when both were broadcast, without harrowing. At one harvest, the yield of clover in treatments sown in May was actually lower than that in the later‐sown plots.In a subsidiary controlled environment experiment to investigate the effect of stage of clover development on cold hardiness (a factor in autumn‐sown swards), plants which were about to initiate stolons (58 days old) had an LD50 of −5·1° compared with −9·3°C for plants 60 days older.It is concluded that autumn sowing delays the time at which optimum clover production is achieved (late in the first full harvest year) and method of sowing does not compensate for this. However, sowing in August under Northern Ireland conditions does not seem to jeopardize the chances of a successful establishment of white clover, and plants should be sufficiently winter hardy to withstand relatively hard freezing conditions.
Assessment of contrasting perennial ryegrasses, with and without clover, under continuous sheep stocking in the uplands. 4. Animal performance in years 4–6
Authors: DAVIES D. A. , FOTHERGILL M. , MORGAN C. T. 
Published: April 2006

AbstractRelative sheep production from Aurora (very early flowering), Mellra (late‐flowering tetraploid) and Aberystwyth S23 (late flowering) perennial ryegrass (Lolium perenne L.) varieties was compared during harvest years 4‐6 (1988‐90) as grass only (200 kg N ha−1) and grass/clover (75 kg N ha −1 in 1988, 0 kg N ha−1 in 1989 and 1990) at Bronydd Mawr Research Centre (310‐363 m) in mid‐Wales. The pastures were continuously stocked with Beulah Speckled Face ewes and their Suffolk cross lambs from spring to mid‐July. From late July to early November only the weaned lambs grazed the swards.Mean (1988‐90) total annual lamb production per hectare from Aurora and Meltra was 70% and 16% more than that from S23. However, the difference between both varieties and S23 was much greater as grass/clover (Aberystwyth S184 small‐leaved type) than as grass‐only swards. Differences between the grasses in individual lamb growth rates were most pronounced during the post‐weaning period, when that on Meltra was 38% and 23% more than on Aurora and S23 respectively.Mean annual lamb output from grass/clover swards was only 70% of that from grass‐only swards during the 2 years when the former swards received no fertilizer N. Averaged over the 3 years (1988‐90) individual lamb liveweight gain post weaning was 38% higher on grass/clover than on grass‐only swards.The results are discussed in relation to those for the first 3 harvest years (1985‐87). It is concluded that, although Aurora was less persistent than both late‐flowering varieties, its superiority in providing an average of 29% more lamb output than S23 during the critical spring period (up to early June) would be of considerable practical significance in upland sheep systems, as would be the overall superiority of the tetraploid Meltra over S23.
Observations on the incidence of plant parasitic nematodes in grassland in England and Wales
Authors: COOK R. , MIZEN K. A. , PLOWRIGHT R. A. , YORK P. A. 
Published: April 2006

AbstractSoil samples taken from one‐ to four‐year‐old swards of white clover and perennial ryegrass at 34 sites, and from older clover/grass swards at 56 sites in England and Wales, were examined for plant parasitic nematodes. Stolons of white clover from 46 of these sites were examined for nematodes. Clover cyst nematode (Heterodera trifolii) and white clover stem nematode (Ditylenchus dipsaci) were found in 62% and 41% of sites respectively. The grass cyst nematode (Punctodera punctata) was present in 56% of 71 sites examined, and other grass cyst nematodes (H. bifenestra and species of the H. avenae group) occurred in 13% and 17% of sites. Two root‐knot nematodes were found, Meloidogyne naasi and M. hapla, in 15% and 4% of the samples examined. Migratory nematodes were extracted from 63 samples, and spiral, pin and lesion nematodes were found in more than 90%. Stunt nematodes were less frequent (65%) and criconematids (19%) were found relatively infrequently. The significance of these observations to grassland productivity is discussed.
Effects of field drainage on the growth of herbage and the liveweight gain of grazing beef cattle
Authors: TYSON K. C. , GARWOOD E. A. , ARMSTRONG A. C. , SCHOLEFIELD D. 
Published: April 2006

AbstractA long‐term field grazing experiment was begun in 1982 to examine the impact of efficient field drainage on herbage and animal production from swards on an impermeable clay loam in the south‐west of England. Drained and undrained lysimeter plots (each of 1 ha) were established on the existing permanent sward and received annual applications of fertilizer N of 200 or 400 kg ha−1. Similar plots were initially ploughed and reseeded with Lolium perenne (cv. Melle), and received fertilizer N at an annual rate of 400 kg ha−1. All plots were continuously stocked by beef cattle and stock numbers were adjusted to maintain a constant sward height and to avoid poaching damage. Results for the first 5 years show that the benefits from drainage were modest and, for beef production, unlikely to pay for its costs over the shorter term. The main benefit was in spring when herbage dry matter yield was 11% greater on the drained plots, but with no significant interaction with fertilizer N level or sward type. This benefit was reduced to 3% on an annual basis, due to the effect of the larger soil water deficits sustained by the drained swards in mid‐season. Drainage increased the annual liveweight gain per ha by the grazing cattle by 11%. Possible mechanisms accounting for these effects are discussed in relation to the influences of seasonal patterns of weather.
The effect of an acid salt‐type additive on the fermentation of grass silages made in bunker silos on commercial dairy farms in Wales
Authors: HAIGH P. M. 
Published: April 2006

AbstractThe fermentation characteristics and chemical composition of 57 first‐cut and 30 second‐cut samples of grass silages, made in bunker silos on commercial dairy farms in Wales in 1990, and treated with a nominal 61 t−1 of an acid salt‐type additive at ensilage, is described. Typical chemical composition of grass cut for ensilage was 156 g kg−1 dry matter (DM) and 28 g kg−1 water soluble carbohydrate (WSC), with 181 g (kg DM) −1 crude protein (CP) and 232 g (kg DM) −1 modified acid detergent fibre (MADF). The effect of additive use was to produce silages with DM 230 g kg−1 pH 3·93, ammonia N 70 g kg−1 total N, with residual WSC 35 g (kg DM) −1, lactic acid 83 g (kg DM) −1, total acids 118 g (kg DM) −1 and butyric acid 0·7 g (kg DM) −1. No significant differences were found between first‐ and second‐cut silages. Silage fermentation was restricted (i.e. lactic acid less than 60 g kg DM−1) in only 20% of the samples.It is suggested that on commercial farms the application rate achieved may be insufficient to produce a restricted fermentation.
Nutrient efficiency and cellular contents of phosphorus and nitrogen in Trifolium repens and a diploid and tetraploid Lotus uliginosus
Authors: HART A. L. , COLLIER W. A. 
Published: April 2006

AbstractTwo cultivars of white clover (Ladino and Kent Wild White) and two cultivars of lotus (Grasslands Maku and G4703) were grown in pots of soil at low to moderate levels of phosphorus (P) supply. Nitrogen supply was by fixation. Cell size and nitrogen, phosphorus and chlorophyll content per cell were estimated from samples of leaf tissue. Maku lotus had larger cells and higher cellular contents of metabolites than the clovers. These measurements support earlier suggestions that, compared with white clover, the higher P‐efficiency (dry matter per unit of internal P) of Maku lotus may be explained by cytological factors without recourse to explanations based on differences in nutrient metabolism. The relatively large cells and high metabolite levels per cell of Maku lotus appear to arise from its creation as an artificial tetraploid.
Proteolysis and amino acid degradation during ensilage of untreated or formic acid‐treated lucerne and maize
Authors: FAIRBAIRN R. L. , ALLI I. , PHILLIP L. E. 
Published: April 2006

AbstractLucerne (Medicago sativa), field wilted to 330 g dry matter (DM) kg−1, and whole‐plant maize (Zea mays), 383 g DM kg−1, were treated with formic acid (FA) at the rate of 4‐5 1 t−1 fresh forage. The effects of FA treatment on proteolysis and amino acid degradation was investigated at several intervals over a 90‐d period of ensilage in laboratory silos. Formic acid treatment produced different patterns of pH decline during ensilage of the two forages, suggesting some degree of crop specificity in response to FA treatment. After 7 d of ensilage of lucerne there were increases of 81% in nonprotein nitrogen (NPN), and 104% in free amino acid nitrogen (FAA‐N), but with FA‐treated lucerne the increases were 39% and 31%, respectively. FA treatment resulted in a reduction in the concentration of most free amino acids in lucerne silage, with the exception of glutamic acid and serine; the branched chain amino acids as well as glycine, tyrosine and proline were significantly (P<0·05) reduced after 3 d of ensilage. By contrast, FA treatment of maize did not significantly (p<0·05) affect the NPN content nor was there a consistent pattern in the changes in FAA‐N. Formic acid treatment of maize did produce a significant reduction (P<0·05) in the concentration of most individual free amino acids at 90 d of ensilage. Overall, FA treatment had a more predictable effect on proteolysis and amino acid degradation in ensiled lucerne than in ensiled whole‐plant maize.
Triticale and other small grain cereals for forage and grain in Mediterranean conditions
Authors: ROYO C. , MONTESINOS E. , MOLINA‐CANO J. L. , SERRA J. 
Published: April 2006

AbstractIn field experiments conducted over 2 years, triticale was compared with barley, bread wheat and oats for its dual‐purpose (forage and grain) capability.The effect of spring forage removal on grain yield ranged from small yield increases (in the triticale and barley genotypes that otherwise lodged) to a 53% decrease, and was dependent on species, genotype, stage of development when cut, and time for recovery before grain harvest. A key factor influencing grain yield after early cutting was the number of spikes that developed.The complete types of triticale were better than the one substituted type tested for dual purpose but, as there is variability among them, selection for good mixed aptitude is possible.The production of the best triticale averaged over 2 years 3 t of forage DM ha‐1 (with 684 kg of crude protein ha‐1) and then 4–3 t of grain ha‐1. In this instance, neither the grain yield nor the number of spikes per plant were reduced after clipping, in spite of the fact that the shoot apices were removed.Plant height and lodging were reduced by a forage cut. In triticale, the number of days to heading was increased even more when the cut was late, but no effect was observed in barley.
Progress in breeding interspecific hybrid ryegrasses
Authors: JONES M. LL. , HUMPHREYS M. O. 
Published: April 2006

AbstractStable hybrids were produced between tetraploid perennial and Italian ryegrasses derived from commercial varieties and germplasm introduced from European collections. Spaced plant characteristics were used to select Fl plants for the production of F2 families which were assessed in small plots for growth and quality traits. Ten of the 19 selected hybrid families were based on perennial ryegrass collected from the Zurich Uplands. The influence of this parental material in improving vegetative growth during early spring, late summer and autumn was demonstrated. Its use in improving feeding value by increasing the water‐soluble carbohydrate content of hybrids was also shown. Consequently, selected hybrid varieties based on this new genetic resource showed considerable improvements in seasonal growth and quality over the older hybrid variety Augusta and Italian ryegrass variety RvP.
Cell wall degrading enzymes for silage. 1. The fermentation of enzyme‐treated ryegrass in laboratory silos
Authors: SELMER‐OLSEN I. , HENDERSON A. R. , ROBERTSON S. , McGINN R. 
Published: April 2006

AbstractThe effects of two commercial cellulase/hemicellulase enzymes derived from Trichoderma reesei on silage fermentation were investigated in three laboratory‐scale experiments. In Experiment 1, perennial ryegrass (Lolium perenne) was treated with enzyme A at the rates of 0, 0·125, 0·250, 0·500 and 0·750 cm3 kg‐1. In Experiment 2, Italian ryegrass (Lolium multiflorum) was treated with the same enzyme at the rates of 0, 0·250 and 0·500 cm3 kg‐1 and with 85% formic acid (3·5 cm3 kg‐1). In Experiment 3, perennial ryegrass was ensiled untreated, with enzyme A (0·250 and 0·500 cm3 kg‐1) and with 0·200 and 0·400 cm3 kg‐1 enzyme B which also contained glucose oxidase. All silages were well preserved. In general enzyme treatment reduced pH and the contents of ammonia nitrogen, neutral detergent fibre and acid detergent fibre, whereas the contents of water‐soluble carbohydrates, acetic acid, lactic acid and ethanol were increased.
Herbage intake and liveweight gain of bulls and steers continuously stocked at fixed sward heights during autumn and spring
Authors: MORRIS S. T. , HIRSCHBERG S. W. , MICHEL A. , PARKER W. J. , McCUTCHEON S. N. 
Published: April 2006

AbstractTwo experiments were conducted to examine the relationship between sward surface height, herbage intake and liveweight gain in beef cattle grazed on pasture. In Experiment 1, two ‘animal types’ (18 Charolais × Angus steers and 18 Friesian bulls) were continuously grazed for 22 days during the late autumn on replicated swards maintained at sward surface heights of 6, 10 and 15 cm. Herbage intakes, assessed from the faecal concentration of chromium delivered from an intraruminal controlled release capsule and the in vitro digestibility of hand‐plucked herbage samples, were curvilinearly related to sward height (r = 0·76, p<0·0·01). Average liveweight gains were 0·02, 0·61 and 1·31 kg d‐1 (P <0·05) and increased linearly (r= 0·84, P <0·001) with sward height. The maintenance organic matter intakes of the steers and bulls, with initial mean (± s.e.) live weights of 225 ± 15 kg and 172 ± 15 kg respectively, were estimated to be 3·6 and 3·5 kg d‐1 respectively. In Experiment 2 (spring) 36 cattle, including 35 of those used in Experiment 1, were reallocated to sward heights of 5, 10 and 15 cm using the same design as for Experiment 1. Average liveweight gains were 0·94, 1·57 and 1·68kg d‐1 (p 0·05) and were curvilinearly related to sward height (r= 0·093, p <0·05). Maintenance intakes could not be reliably extimated for the cattle in Experiment 2 because few animals had liveweight gains close to zero. These trials confirm that liveweight gain in continuously grazed finishing steers and bulls increases with sward surface height to maximum of 8–10cm with spring ryegrass/white clover pastures while, in autumn, swards of 12–15cm height are required to achieve maximum performance.
Component yields and quality of binary mixtures of lucerne and perennial, Italian or short rotation hybrid ryegrass
Authors: JUNG G. A. , SHAFFER J. A. 
Published: April 2006

AbstractStudies were conducted to characterize sward dynamics of lucerne (Medicago sativa L.) and perennial, Italian or short rotation hybrid rye‐grass (Lolium perenne L. and L. multiflorum Lam.) binary mixtures under hay management. Lucerne/timothy (Phleum pratense L.) mixtures were included as controls. The study was conducted on two farms in central Pennsylvania, USA on Hagerstown silt loams (fine, mixed, mesic hapludalf). Total dry matter yield, grass yield and yield of digestible dry matter were higher for tetraploid perennial and tetraploid Italian ryegrass mixtures than for timothy mixtures. Seasonal production differed for the three kinds of ryegrass. Italian ryegrass dry matter yields were higher in cuts 2 and 3 than perennial ryegrass yields. Grass yields represented 34%, 24% and 12% of total yields of the Italian, perennial or short rotation, and timothy mixtures, respectively. However, herbage in vitro dry matter digestibility of Italian was lower than that of perennial ryegrass.The tetraploid perennial ryegrasses Grimalda and Reveille had high‐ranking N concentrations more frequently than other cultivars, while Bar‐vestra and Reveille tetraploid perennials and Bison short rotation ryegrass had high‐ranking dry matter digestibility values more frequently than the other cultivars. Perennial ryegrass cultivars and Lipo tetraploid Italian ryegrass persisted well for 4 years and produced higher yields with a lower weed content than timothy mixtures. It is concluded that perennial ryegrasses and Lipo Italian ryegrass should be recommended over timothy, as companion grasses with lucerne.
The effects of forage preservation method and proportion of concentrate on nitrogen digestion and rumen fermentation in cattle
Authors: JAAKKOLA S. , HUHTANEN P. 
Published: April 2006

AbstractA 6 × 6 Latin square experiment with a 2 × 3 factorial arrangement of treatments was used to study forage preservation method and level of concentrate in a diet on organic matter (OM) and N digestion and rumen fermentation. Six bulls, each fitted with ruminal and duodenal cannulae, were given unwilted silage (S) or barndried grass (G) prepared simultaneously from the same timothy sward. The forages were fed together with 250 (L), 500 (M) or 750(H)g concentrate dry matter (DM)kg‐1 total diet DM. The concentrate consisted of barley (875 gkg‐1) and rapeseed meal (125g kg‐1). The feeding level was 80g DMkg‐1 live weight0·75.The apparent digestibility of OM was similar for S and G diets, and increased linearly (P < 0·001) with increasing level of concentrate. The flow of microbial N at the duodenum and the apparent efficiency of microbial protein synthesis in the rumen were higher (P < 0·05) with S than with G diets. Increasing the concentrate level increased linearly (P < 0·05) the amounts of total N and microbial N at the duodenum, whereas the synthetic efficiency was not significantly affected. The mean rumen pH decreased linearly (P < 0·001) from 6·43 to 6·03 with increasing concentrate level. The molar proportion of acetate (Ac) in the rumen volatile fatty acids (VFA) showed a linear (P < 0·001) and quadratic (P < 0·01) decrease, and that of butyrate (Bu) a linear (P < 0·001) increase when the level of concentrate was increased. The proportion of propionate decreased slightly with both forages when the amount of concentrate was increased from level L to M. A further increase to level H increased propionate from 157 to 170 mmol mol‐1 of total VFA with S and from 157 to 188 mmol mol‐1 with G, the effect of concentrate level being not significant. The number of protozoa increased linearly (P < 0·001) as the level of concentrate increased. The changes in the rumen fermentation patterns during the feeding cycle were greater for S than for G diets.
Influence of growth stage and season on the energy value of fresh herbage. 1. Changes in metabolizable energy content
Authors: GIVENS D. I. , MOSS ANGELA R. , ADAMSON A. H. 
Published: April 2006

AbstractThe energy value and chemical composition of 70 herbages harvested over two years as either spring primary growths of increasing maturity (n= 32), summer regrowths (n= 14) or autumn regrowths of increasing maturity (n= 24) are reported. The herbages, which were dominated by perennial ryegrass, were harvested from commercial grassland on four sites in England in1986 (year 1) and 1987 (year 2). Digestibility and energy values were determined in vivo using wether sheep.In year 1, autumn regrowths had significantly (P < 0·05) lower neutral detergent fibre concentrationsthan summer regrowths, and lignin was lower (P < 0·05) in spring than in summer herbages. In year 2, autumn herbages had significantly(P < 0·05) higher concentrations of crude protein and hemicellulose than summer and autumn herbages. Spring herbages had higher concentrations of water‐soluble carbohydrates than summer (P 0·01) and autumn (P < 0·001) herbages.A higher (P < 0·05) metabolizable energy (ME) concentration was observed in spring compared with summer herbages in year 2 and in general there was considerably more variability in the values for the spring growths, ME content fell with increasing maturity in spring growths(0·046 and 0·035 MJ kg‐1 DM per day; years 1and 2 respectively) and this decline was 3–4 times faster than for autumn‐harvested material (0·012 and 0·017 MJ kg‐1 DM per day; years 1 and 2 respectively). In both years only immature spring herbages consistently produced ME contents in excess of 11·9 MJ kg‐1 DM.For 15 of the herbages the proportion of gross energy intake (GEI) lost as methane was measured directly using respiration chambers. The mean methane energy loss was 0·07 of GEI (range 0·057–0·082). A commonly used publish equation for predicting methane energy loss was shown not to be appropriate, although no relationships could be established between methane energy loss and either energy digestibility in vivo or chemical composition.