bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of early season sward management on sward quality and lamb liveweight gain during autumn
Authors: CHESTNUTT D. M. B. 
Published: April 2006

AbstractIn two experiments (1990 and 1991) perennial ryegrass (cv. Talbot) pasture was subjected to six different management treatments by adjusting stock numbers to achieve set sward heights for set periods between turn‐out in early April and weaning in early July. The main objective of the experiments was to measure the effect of differences in sward management up to July on subsequent sward type, and the effect of sward type on the performance of weaned lambs between mid‐July and early October when all swards were grazed at a sward height of 7 cm. In Experiment 1 swards were grazed at 7 cm initially and then reduced to 3 cm at various dates and maintained at 3 cm until early July. In Experiment 2 swards were grazed initially at 7 cm, and this was reduced to 3 cm and then allowed to return to 7 cm at various dates up to early July.Grazing at a sward height of 7 cm up to weaning, in early July, gave mean twin lamb growth rates of 310 g d−1, while at a tower sward surface height of 3 cm lamb growth rate was reduced to 206 g d−1 The density of seed heads produced from July was strongly influenced by earlier management. Grazing at 7 cm up to July gave a high density of seed heads (213m−2), and this reduced (126 m−2) by grazing to 3 cm. Seed heads were almost eliminated (17 m−2) by grazing at 7 cm until late June followed by grazing down to 3 cm in early July. Reducing sward surface height from 7 cm to 3 cm at an earlier date tended to increase the development of seed heads from early July. Where swards were grazed from 7 cm to 3 cm and then allowed to return to 7 cm, the later in the pre‐weaning period this took place the greater the reduction in seed head development. Greater seed head density was associated with a significant decrease in the nitrogen content of the herbage on offer in Experiment 2, but an increase in modified acid detergent (MAD) fibre content was not significant.Despite the differences in the sward type on offer, the effect on weaned lamb growth rate was small. Lamb liveweight gain during autumn was significantly reduced in Experiment 2 following earlier grazing at 7 cm compared with 3 cm, but liveweight gain differences in Experiment 1 were not significant.
Concentrations of N, P, K, Ca, Mg and Na in perennial ryegrass and white clover leaves of different ages
Authors: WILMAN D. , ACUÑA P. G. H. , MICHAUD P. JOY 
Published: April 2006

AbstractLeaf blades of perennial ryegrass (Lolium perenne) at five developmental stages, from unemerged to dead, were collected from cut swards grown under field conditions. Similarly, leaflets of white clover (Trifolium repens) at four developmental stages, from tightly folded to proximal to the youngest fully developed leaf, were collected. The leaves were analysed for N, P, K, Ca, Mg and Na.In perennial ryegrass, the concentration of N declined by about half and those of P and K declined by about two‐thirds, as leaves aged. By contrast, the concentration of Ca increased more than fivefold and that of Mg about twofold as leaves aged. The concentration of Na initially increased more than twofold but then declined as leaves died. In white clover the concentration of N declined by about 20% as leaves aged, while the concentrations of P and K declined by about 50%; the concentration of Ca increased about fivefold, that of Mg declined by about 15% and that of Na increased by about 15%.The application of N increased the concentrations of N and K in ryegrass leaf blades at all stages of development. The application of P increased the concentrations of P and Na in the leaves of both species.
The intake and performance of cashmere goats grazing sown swards
Authors: MERCHANT MARGARET , RIACH D. J. 
Published: April 2006

AbstractAn experiment was conducted to examine the relationships between sward surface height and the intake and liveweight gain of lactating female goats and their single kids and of 12‐month‐old castrated male goats continuously grazing grass pasture. Herbage intake was measured using the n‐alkane marker technique. Goats grazed the experimental area from May to August at nominal sward heights of 3–4, 5–6, 7–8 and 9–10 cm. Sward heights achieved were variable but were consistently ranked in treatment order.The herbage intake of females [57‐140 g DM (kg LW0.75)−1 d−1] and castrates [26‐88 g DM (kg LW0.75)−1 d−1] increased linearly with sward height over the range 3.2‐11.0 cm. The liveweight change of females and castrates reflected the pattern of change in sward height.The herbage intake of kids [17‐41 g DM (kg LW0·75)−1 d−1] was not related to sward height, but there was a consistent increase in liveweight gain with sward height from 98 to 129 g d−1. The herbage intake of kids did not increase with age with means of 25–29 g DM (kg LW0·75 d−1 for kids aged 9–17 weeks.There was evidence that all classes of goat selected green leafy material of high digestibility.
Effects of treating low dry‐matter grass with a bacterial inoculant on the intake and performance of beef cattle and studies on its mode of action
Authors: KEADY T. W. J. , STEEN R. W. J. 
Published: April 2006

AbstractA randomized block design experiment involving thirty beef cattle (mean initial live weight 462 kg) was carried out to evaluate a bacterial inoculant based on a single strain of Lactobacillus plantarum as a silage additive and to provide further information in relation to its mode of action. Three herbages were harvested on 10 August 1989 using three double‐chop forage harvesters from the first regrowth of a perennial ryegrass sward which had received 170 kg N, 25 kg P2O5, and 42 kg K2O ha−1. They received either no additive (silage C), formic acid at 2·91 (t grass)−1(silage F) or the inoculant at 3·21 (t grass)−1 (silage I). Mean dry‐matter (DM), water‐soluble carbohydrate and crude protein concentrations in the untreated herbages were 158g kg−1, 88 g (kg DM)− and 183g (kg DM)−1 respectively. For silages C, F and I respectively, pH values were 4·01, 3·57 and 3·62; ammonia N concentrations 117, 55 and 77 g (kg total N)−1; and butyrate concentrations 2·18, 0·50 and l·24g (kg DM)−1. The silages were offered ad libitum and supplemented with 2·5 kg concentrates per head daily for 77 days. For treatments C, F and I, silage DM intakes were 6·59, 7·25 and 6·80 (s.e. 0·074)kg d−1; metabolizable energy (ME) intakes 86,99 and 94 (s.e. 0·8) MJ d−1; liveweight gains 0·90, 0·97 and 1·02(s.e.0·066) kg d−1; carcass gains 541,656 and 680 (s.e. 34·0) g d−1. Inoculant treatment increased DM (P < 0·01), organic matter (P < 0·01), crude fibre (P < 0·05), neutral detergent fibre (NDF) (P < 0·05) and energy (P < 0·05) digestibilities, the digestible organic matter concentration (P < 0·01) and the ME concentration (P < 0·05) of the total diets. Additive treatment altered rumen fermentation patterns but had little effect on the rumen degradability of silage DM, modified acid detergent (MAD) fibre, NDF or hemicellulose. It is concluded that treatment with the inoculant improved silage fermentation and increased digestibility, had little effect on silage DM intake but significantly increased carcass gain to a level similar to that sustained by a well‐preserved formic acid‐treated silage
Effect of supplementation on production by spring‐calving dairy cows grazing swards of differing clover content
Authors: WILKINS R. J. , GIBB M. J. , HUCKLE C. A. , CLEMENTS A. J. 
Published: April 2006

AbstractAn experiment was carried out to examine the effect of supplementation on the performance of spring‐calving dairy cows grazing swards of differing perennial ryegrass and white clover content. Seventeen heifers and sixty‐four Friesian cows in their third to ninth week of lactation were turned out onto one of three pastures with different proportions of perennial ryegrass and white clover. Nine animals on each pasture received either 0, 2 or 4 kg d−1 of a concentrate with a crude protein concentration of 180 g kg−1 dry matter (DM). Prior to grazing, swards contained proportionately 0·01 (L), 0·15 (M) and 0·20 (H) of total DM as clover. During the experiment, grazing pressures were adjusted by movement of buffer fences to maintain compressed sward heights at 6 cm. Samples taken 26 and 68 d after the start of grazing showed little change in the proportion of clover in sward L (< 0·01 and 0·02 respectively), but convergence in the proportion of clover in swards M and L (0·08‐0·16 and 0·10‐0·15 respectively). Mean daily yields of milk, fat, protein and lactose increased significantly with increased clover content and, even without supplementation, daily yields were 25·4, 0·98, 0·73 and 1·09 kg respectively on sward H. Of the milk components, only protein was significantly increased by increasing sward clover content. The response in milk yield to supplementation was greater on sward L than on swards M and H.
Influence of root competition on compatibility between white clover and perennial ryegrass populations during seedling establishment
Authors: COLLINS ROSEMARY. P. , RHODES I. 
Published: April 2006

AbstractPlants of a white clover population, Ac 3785, were grown in binary mixtures with perennial ryegrass cv. Talbot and the ‘coexisting’ population, Ba 10281, in boxes. Treatments imposed were ‘no root competition’ and ‘full competition’, which prevented or allowed the root systems of the competing species to intermingle respectively. Shoot competition was permitted in both treatments. Measurements of dry‐matter yield and leaf area of the clover and grasses were made on three occasions following sowing.The dry‐matter yield of both grasses was higher than that of clover at all three harvests and under both treatments, and this yield advantage tended to increase with time. Both grasses yielded more under full competition than where root competition was prevented. Talbot was higher yielding than the coexisting population under both treatments. Clover dry weight and leaf area index (LAI) were considerably higher under the ‘no root competition’ treatment. There was no effect of companion grass on clover dry weight, but clover LAI was significantly higher with its coexisting population than with Talbot in the ‘no root competition’ treatment.The LAI and dry weight data indicate that clover leaf morphology changed in response to the companion grass where root competition was prevented. Thus, the superior aerial compatibility of Ac 3785 with its coexisting grass was limited by below‐ground factors. Possible ecological reasons for this effect are discussed.
Forage availability from a temperate pasture managed with intensive rotational grazing
Authors: KANNEGANTI V. R. , KAFFKA S. R. 
Published: April 2006

AbstractSuccessful integration of rotational grazing into livestock production systems requires estimates of pasture growth rates for feed budgeting of daily animal intake. By matching livestock nutrient demand with forage availability, over‐feeding of supplements can be minimized, which reduces feed costs and the need lo manage surplus nutrients, A three‐year grazing study was carried out on a Kentucky bluegrass (Poa pratensis L.)‐dominant pasture to estimate the daily quantity of herbage available to cattle in an intensive, rotational grazing system. Herbage production, species composition, and forage quality were determined in each of the six grazing cycles in a year, from April until September. The average length of a grazing cycle was 28·6 d, with 2·7 d for duration of grazing on a paddock. Pre‐grazing and post‐grazing sward heights, measured with a plate meter, were 14 and 7 cm, and the corresponding herbage masses were 1955 and 775 kg DM ha−1 respectively. Under adequate soil moisture during 1989, herbage available for daily intake was 53 kg ha−1 from April until mid‐ August, declining to approximately 32 kg ha−1 d−1 by the end of September. Distribution of this herbage was fairly uniform until the end of August. However, a dry summer in 1991 reduced herbage availability to 15 kg ha−1 d−1. Bluegrass and white clover (Trifolium repens L.) formed 70% of the herbage yield during the period April–June. Later in the season, dead matter and other species increased, reducing the contribution of bluegrass and clover to approximately 60% of total dry matter. While these pastures have the potential to provide significant amounts of forage for 5–6 months in a year, additional on‐farm forage reserves are needed during periods of water stress.
The composition of first‐cut grass for ensilage in England and Wales from 1988 to 1991
Authors: HAIGH P. M. 
Published: April 2006

AbstractA total of 2225 samples of herbage, typical of that taken for first‐cut silage on commercial farms in England and Wales, was taken between 1988 and 1991. Samples were analysed for dry matter (DM), water soluble carbohydrate (WSC), crude protein (CP) and metabolizable energy calculated from modified acid detergent fibre. The results were used to investigate the effect of weather conditions upon herbage quality for ensilage. In general, in areas of high rainfall, i.e. western areas, herbage DM and WSC were significantly lower than in eastern areas, whilst the reverse situation occurred with CP. Italian ryegrass (IRG) had a significantly higher WSC and lower CP than other grasses, whilst samples from permanent pasture (PP) had significantly lower DM and WSC, and significantly higher CP than other grasses. It was calculated that to produce a WSC concentration in the fresh grass of 37 g kg−1, to produce well‐fermented silage without additive use, IRG grown in the east would require a DM of 160 g kg−1, In contrast PP grown in the west would require a DM content of 250 gkg−1.
A comparison of the ensilage, in an anaerobic cabinet, of grass, either fresh or when thawed after deep freezing
Authors: WAYMAN J. , CHAMBERLAIN D. G. , WILLIAMS A. G. 
Published: April 2006

AbstractThe suitability of freezing a large amount of grass from a single harvest for use in a series of experiments to investigate silage fermentation and its manipulation was examined. Perennial ryegrass, harvested in late June, was ensiled in sterile polythene bags inside an anaerobic cabinet; some was also stored frozen at ‐20°C for up to nine months before ensiling in a similar manner. The course of fermentation was followed using not only conventional chemical and microbiological analyses, but also by measuring microbial metabolic activity in vitro. Freezing and thawing affected the chemical composition and the microbial populations on the grass, and there were differences in the changes occurring in thawed grass during ensilage, probably related to damage to plant cells and impaired microbial activity associated with freezing and thawing. For both the grasses and the silages made from them, it was clear that the number of microorganisms present was not a reliable guide to microbial metabolic activity. Although the fermentation of frozen‐and‐thawed grass did not simulate precisely the fermentation occurring with fresh grass, it is concluded that, when used judiciously, the ensilage of thawed grass can be a useful experimental tool, particularly in the initial screening of manipulants of fermentation.
Infestation of improved grasslands by Juncus effusus L. in the catchment of the River Tyne, Northern England: a field survey
Authors: CHERRILL A. 
Published: April 2006

AbstractSoft rush, Juncus efffusus L., is a widespread weed of managed grasslands. In 1991, a sample‐based field survey of the weed's distribution in improved grasslands was conducted within the catchment of the River Tyne in Northern England. The land classes of the Institute of Terrestrial Ecology (ITE) environmental landscape classification system were used as sampling strata. In total, 182 I‐km grid squares were surveyed. Areas of improved grassland and levels of J. effusus infestation differed significantly between land classes, but there was also wide variation between grid squares within land classes. Most squares within a land class had no J. effusus, while a proportion had large areas. Extra‐polation from the sample data suggested that an area equivalent to 24·0% of the 3000km2 land surface of the catchment supported improved grassland, of which 3·5% was infested with the rush. Infestation of improved grassland was estimated to be lowest in the lowlands (2·0% of improved grassland), intermediate in the marginal uplands (3·0% of improved grassland) and greatest in the uplands (10·8% of improved grassland). Data from the Farm Business Survey, on broad patterns of utilization of improved grassland for hay, silage and livestock in lowland, marginal upland, and upland landscapes in the catchment, do not readily explain the observed variation in infestation levels, which may reflect local factors and the availability of propagules from adjacent rough grazing land.
Characteristics of microsites with and without white clover in two field swards
Authors: MATTHEW C. , CRESSWELL A. , HAGGAR R. J. 
Published: April 2006

AbstractA microsite comparison technique was used to characterize differences between clover and non‐clover patches in two field swards, one grazed by cattle and the other sheep‐grazed. Within clover patches of both swards, ryegrass tiller weight and the percentage of dead dry matter (DM) was lower than in non‐clover patches, while the ratio of other grass DM: ryegrass DM was higher. Leaf senescence rates for ryegrass tillers within clover patch microsites were less than half of those of non‐clover patch microsites, and consequently net leaf production was higher. At clover patch microsites, soil carbon dioxide levels were lower, soil oxygen levels higher and levels of N, Na, Ca, Mg and P in the ryegrass component of the herbage DM were elevated, compared with non‐clover patch microsites.
Sward dynamics of a smooth‐stalked meadowgrass dominantwhite clover sward rotationally grazed by cattle and/or sheep
Authors: MURPHY W. M. , BARRETO A. D. MENA , SILMAN J. P. 
Published: April 2006

AbstractThis experiment was carried out to study the responses of sward components (particularly white clover, Trifolium repens) to grazing management in a natural sward dominated by smooth‐stalked meadowgrass (Poa pratensis) syn. Kentucky bluegrass. Treatments during two grazing seasons (1989–90) were: cattle grazing alone (C); cattle grazing followed by topping (CT); cattle grazing followed by sheep grazing (CS); and sheep grazing alone (S). Mean target pre‐ and post‐grazing herbage masses were 2200 and 1100 kg DM ha−1, estimated by single‐probe electronic capacitance meter. Sward component dynamics were monitored using turf dissections, marked white clover stolons, and ring‐toss white clover leaf counts. Component and sward data for the C, CT, CS and S treatments respectively, were: number of white clover leaves m−2, 1295, 1384, 1408, 900 (s.e. ± 108); number of leaves per growing point, 3·2, 3·4, 3·0, 2·8 (s.e. ± 0·2); herbage accumulation (t DM ha−1), 5·16, 5·02, 5·87, 8·28 (s.e. ±0 08); rejected herbage (% pasture area) 39·7, 7·7, 16·0, 0 (s.e. ± 75); and annual net herbage production (t DM ha−1) 3·39, 4·35, 4·99, 8·28 (s.e. ± 0.07). Swards grazed by sheep alone contained less white clover, but regrew quicker and produced more herbage than other treatments. Close topping or grazing by sheep following dairy cattle grazing decreased sward rejection by cattle. These treatments maintained more of the pasture in better condition for subsequent cattle grazing, resulting in greater net herbage production than where no post‐cattle grazing treatment was used.
The effects of treating low dry‐matter, low digestibility grass with a bacterial inoculant on the intake and performance of beef cattle, and studies on its mode of action
Authors: KEADY T. W. J. , STEEN R. W. J. 
Published: April 2006

AbstractThis experiment evaluated a bacterial inoculant based on a single strain of Lactobacillus plantarum as a silage additive. Three silages were harvested on 8 September 1989 from the second regrowth of a perennial ryegrass sward, which had received 167 kg N, 28 kg P2O5 and 45 kg K2O ha−1. Mean dry matter (DM) and water soluble carbohydrate concentrations of the herbages at ensiling were 148 g kg−1 and 78 g.(kg DM)−1 respectively. Herbages were treated with either no additive (C), formic acid (3·0 1 t−1) (F) or the inoculant (3·0 1 t−1) (I) and were ensiled in three 80‐t capacity silos. For silages C, F and I respectively, pH values were 4·70, 3·77 and 4·47, ammonia‐N concentrations were 192, 111 and 182 g (kg total N)−1 and butyrate concentrations were 6·8, 1·8 and 7·1 g (kg DM)−1. The silages were offered ad libitum and supplemented with 2·0 kg concentrates per head daily to thirty‐six heifers (mean initial live weight 442 kg). For silages C, F and I, silage DM intakes were 12·7, 14·4 and 14·1 (s.e. 0·42) g (kg live weight)−1, metabolizable energy intakes were 155, 166 and 172 (s.e. 5·1) kJ (kg live weight)−1, and estimated carcass gains were 456, 519 and 518 (s.e. 28·1) g d−1 respectively. A further 18 similar cattle were used in studies on the digestibility of the silages, and rumen degradation of each was estimated with three mature cattle. Inoculant treatment significantly increased crude fibre (P <0·01), neutral detergent fibre (P <0·01), modified acid detergent fibre (P <0·01), hemicellulose (P <0·05) and N digestibilities (P <0·05) and tended to increase N retention from the total diet. It is concluded that although treatment of herbage that was difficult to ensile with the inoculant did not improve silage fermentation, it significantly increased digestibility, especially of the fibre fractions, and silage DM intake and tended to increase animal performance to levels similar to those achieved with a well preserved formic acid‐treated silage. Increases in silage DM and metabolizable energy intakes are likely to have been attributable to the effects of the inoculant on digestibility, especially of the fibre fractions.
Effect of sheep, deer and cattle dung on herbage production and soil nutrient content
Authors: WILLIAMS P. H. , HAYNES R. J. 
Published: April 2006

AbstractA field experiment compared the effects of sheep, deer and cattle dung on pasture growth and soil nutrient status. Sheep and deer dung pellets degraded rapidly within three to eight weeks, while it was 12 months before all visible cattle dung had gone from the soil surface. The cattle dung initially reduced herbage yield owing to smothering. However, after 40 days, herbage around the edges of the dung patch responded positively to the dung and more dry matter was produced in this patch than in the control patch during the first 12 months. There was no measurable herbage response to sheep dung, but deer dung significantly increased herbage production. While the rate of nutrient application per unit area was similar for sheep and deer dung, the latter was more evenly spread within the patch area. Consequently, a greater percentage of pasture plants in the patch received nutrient additions from the deer dung and a measurable response was recorded. Twelve months after dung application, soil nitrate, phosphate and organic C were higher in dung patches than in the control patches. In cattle dung patches, this response was accompanied by higher microbial biomass C levels, arylsulphatase and arylphosphatase activities. Some residual effect on organic C levels was still evident three years after cattle dung application.