bluuebunny/crossref_metadata_2025_split huggingface dataset:
Susceptibility to losses during mechanical silage and haymaking operations in relation to grass dry matter content
Authors: MCGECHAN M. B. 
Published: April 2006

AbstractA series of laboratory experiments is described to investigate the susceptibility of grass forage to losses during mechanical field conservation operations in relation to dry matter content. Losses were measured during a simulated manual ‘tedding’ treatment carried out on grass samples being dried on a laboratory thin‐layer drying rig. Values of loss per successive treatment remained at a near constant low level at low dry matter (DM) contents, except for a somewhat higher loss level from the first treatment. As DM content rose above about 60%, the level of loss per treatment rose rapidly with increase in DM content. A relationship between loss per treatment and DM content was derived from the data by a bilinear regression analysis, and this will be incorporated into an Operational Research model of forage conservation systems.
The effect of some invertebrate species on the growth of white clover (Trifolium repens L.) in the lahoratory
Authors: MOWAT D. J. , SHAKEEL M. A. 
Published: April 2006

AbstractIn laboratory experiments to clarify earlier field observations, Sitona lepidus larvae caused significant damage to established clover plants at infestations of approximately 1–2 per plant. When eggs were placed on the soil, cultivars of differing cyanogenic capacity were damaged equally. The plants did not recover when larval feeding ended.Leatherjackets, slugs and ‘lucerne flea’ fed most on the least cyanogenic cultivars, even where no choice was offered. Plants ultimately recovered from damage by leatherjackets. Deroceras reticulatum caused more damage than did Arion fasciatus. The proportion of leaves damaged by lucerne fiea was highest in the least cyanogenic eultivar but also tended to increase in the most cyanogenic cultivar, confirming a field observation. At high population densities lucerne flea was capable of killing some seedlings but was not tested against established plants.
The effects of simulated continuous grazing on development and senescence of white clover
Authors: JONES D. R. , DAVIES ALISON 
Published: April 2006

AbstractTwo experiments investigating the effects of simulated continuous defoliation on white clover development and senescence are described. Stolons growing in boxes in a glasshouse were defoliated repeatedly by hand to simulate different intensities of continuous grazing by sheep. The experiments continued in both instances until eleven leaves had been produced on stolons in the most favourable treatment.It was found that leaf dry matter production was reduced in proportion to the leaf complement of the stolon. Reduction of the leaf complement from two leaves to one leaf led to a reduction in subsidiary branch production of about 25% and an increase in percentage dead stolon from 33 to 44%, If no fully expanded leaves were retained branch production fell to 40% or less of that observed when two leaves were retained.Stolons growing in swards continuously grazed by sheep usually have a green leaf complement varying between zero and two leaves per growing point. The consequences of maintaining different leaf complements in this range are discussed in the light of the current experiments.
Use of the in situ technique in the study of degradation of lucerne and smooth bromegrass genotypes
Authors: MATHISON G. W. , JAHN H. G. , WALTON P. D. , MILLIGAN L. P. 
Published: April 2006

AbstractSix lucerne (Medicago sativa) genotypes (Beaver, Vernal and four other strains being developed at the University of Alberta) and five smooth bromegrass (Bromus inermis) genotypes (Carlton, Magna and three genotypes being developed) were examined in terms of forage dry matter (DM) yield and degradability, as determined by the rate and amount of material which disappeared from bags suspended in the rumen of cattle. Dry matter yield did not differ (p > 0·05) between lucerne genotypes at first cut. The smooth bromegrass strain 517 had a proportionately Oil higher (P < 0·05) DM yield than did the Magna strain. No differences (P < 0·05) were detected within either smooth bromegrass or lucerne genotypes for 48 or 60 h in situ DM degradability. The 416E smooth bromegrass genotype, however, had a significantly higher (P < 0·05) rate of DM degradation in the rumen than the other genotypes and also exhibited a longer (P < 0·05) lag period before a significant amount of DM degradability occurred. In the in situ technique, approximately eighteen bags would have been needed to obtain DM degradability measurements with a confidence interval of 0·04 for DM degradability of a probability of 0·95. Further in vivo studies with the bromegrass genotypes are warranted to ascertain if the differences in digestion rates and lag times are related to meaningful differences in animal intake and digestibility.
The nutritional evaluation of Italian ryegrass cultivars fed as silage to sheep and cattle
Authors: MOSELEY G. , JONES E. L. , RAMANATHAN V. 
Published: April 2006

AbstractThree feeding trials with big bale silage were carried out to determine whether previously established intake differences between artificially dried Italian ryegrass cultivars could be repeated under differing conditions of food preparation and presentation. The silage was prepared in 2 consecutive years from the same field crop and fed to groups of cattle in both years. The second year silage was also fed to sheep indoors. All animals were fed ad libitum and the voluntary intakes recorded for groups of cattle and individual sheep. Chewing activity was also recorded on all groups of sheep.The chemical composition of the two cultivars as fresh grass was similar in 1984 but there were small differences in 1983 with Tarquin showing slightly higher organic matter digestibility (DOMD) and lower dry matter and water‐soluble carbohydrate compared to RvP. The only consistent differences in silage composition between cultivars was a slightly higher level of modified acid detergent (MAD) fibre in RvP compared to Tarquin. Despite these small differences the voluntary intake of cattle fed Tarquin was 19% higher than RvP in the first year and 35% in the second, while sheep showed a similar difference of 40% with the second year silage.Recording of jaw activity with sheep showed that animals spent 40% more time eating and 27% more time ruminating RvP than Tarquin per unit of food eaten. This suggested that the intake differences, which were independent of digestibility, were related to the physical resistance of the feed to breakdown by chewing. These differences depend on the structural characteristics of the plants and were associated with differences in leaf/stem ratios and MAD‐fibre content. These are less likely to be affected by the method of conservation or feed presentation and, although the degree of difference between the cultivars changed with the different procedures, the inherently higher intake of Tarquin persisted.
Effect of plant density on stolon growth and development of contrasting white clover (Trifolium repens) varieties and its influence on the components of seed yield
Authors: MARSHALL A. H. , JAMES I. R. 
Published: April 2006

AbstractPlants of two contrasting white clover varieties (cv. Aberystwyth S184 and Olwen) were planted in the field in spring in each of 2 years at four densities (9, 25, 49 and 100 plants m−2) in 1‐m2 plots. The effect of plant density on stolon growth and development and the components of seed yield was subsequently measured.Stolon growth and development was influenced by plant density, variety and year. At low plant densities both white clover varieties produced longer primary stolons than at higher densities. Plant density, however, had no significant effect on the number of inflorescences at harvest. At the high stolon densities there were significantly fewer reproductive nodes per primary stolon than at the lower plant densities. Plant density did not significantly affect any other seed yield components, but the number of inflorescences at harvest, florets per inflorescence, seed set per floret and 1000‐seed weight were all significantly influenced by both variety and year.The relationship between the vegetative and reproductive growth of white clover is discussed in relation to plant density, variety and climate and the possible role of defoliation managements on inflorescence development.
The contribution of different white clover cultivars to the nitrogen yield of mixed swards
Authors: LAIDLAW A. S. 
Published: April 2006

AbstractThe annual contribution of clover to a mixed sward for 5 years was compared for a range of cultivars, viz. S1OO, Sabeda, Blanca and Olwen, in order of increasing leaf size. The contribution referred to as‘clover‐derived nitrogen N', was measured as the difference between N harvested in mixed swards and that in similarly treated swards devoid of clover. The swards were harvested four or five times each year and received N fertilizer, annually, at 0, 30, 60 or 90 kg N ha−1 in March.Blanca swards had the highest clover‐derived N yield in the second year and lowest in the fourth year. By the fifth year Sabeda and S100 (medium leaved cultivars) were contributing more N than the other two cultivars. When related to the amount of clover harvested, S100 had the highest value in the second year and S100 and Sabeda in the third year. Relating the total lover‐derived N harvested over the 5 years to the amount of clover harvested, S100 had an efficiency of contribution of 54‐3 kg N t−1 dry matter (DM) compared to a mean of 49 0 kg N t−1 clover DM for the other three cultivars. Nitrogen fertilizer reduced the contribution of clover N in the first 3 years owing to a reduction in clover yield, but it did not affect clover's efficiency to contribute N.It is concluded that although the smallest leaved type of the four (S100) made the most efficient N contribution to the sward more information is required to relate morphology of clover to its capability to contribute N directly or indirectly to the sward.
A simulation model to predict the drying time for pasture hay
Authors: GUPTA M. L. , MACMILLAN R. H. , McMAHON T. A. , BENNETT D. W. 
Published: April 2006

AbstractA hay drying model (HAYDMO) which predicts the moisture content of pasture hay is described. It uses multiple regression equations based on field drying experiments with conditioned and unconditioned hay and predicts hourly changes in moisture content for both day and night and also those due to rain. The model can be used with three different combinations of weather, including hourly wet and dry bulb temperatures, radiation, wind speed and rainfall. Testing HAYDMO revealed a satisfactory agreement between predicted and observed moisture contents
Initial bacteria] numbers on lucerne prior to ensiling
Authors: MUCK R. E. 
Published: April 2006

AbstractPopulations of lactic acid bacteria (LAB) on lucerne before and after havesting were extensively monitored over a two‐year period and correlated with weather data, various wilting parameters and equipment used for harvest. The LAB on standing lucerne were below detectable levels (<10 colony forming units (CFU) g lucerne−1). Immediately after mowing, low levels of LAB (51 CFU g−1) were found on over half the samples. During wilting, the population of LAB generally increased. The amount of increase was affected primarily by the average air temperature during wilting, the length of wilting and the drying rate. The first two variables were positively correlated with bacterial growth whereas increased drying rate adversely affected LAB numbers. If the LAB numbers in the swath were below 100 CFU g−1 prior to chopping, the forage harvester inoculated the chopped lucerne an level of 102 to 104 CFU g−1, depending on air temperature. Considering these factors, LAB counts on chopped lucerne could be predicted within one order of magnitude approximately 95% of the time.
Criteria for breeding forages of improved feeding value: results of a Delphi survey
Authors: WHEELER J. L. , CORBETT J. L. 
Published: April 2006

AbstractProgress in improving the feeding value (FV) of forage plants has been slow despite the benefits to animal production that can result from using plants of intrinsically higher FV. The slow progress is due in part to a lack of consensus on the criteria to be used in breeding or selecting forages of high FV. This paper reports the use of the Delphi technique to obtain such a consensus from an international panel of specialists in grazing animal production.The specialists, from Europe, USA, New Zealand and Australia, ranked eleven criteria for improving the FV of grasses and legumes for liveweight gain and for wool production.In general, the primary criteria chosen were high digestibility, easy communication, high nonstructural carbohydrate, high crude‐protein and, for sheep kept primarily for wool production, a high sulphur‐amino acid content. High relative palatability, high lipid‐content and erect growth habit were ranked as least important. It was generally considered that mineral content and anti‐quality constituents should be monitored rather than making them specific breeding objectives, although some exceptions were noted. Minor importance was attached to having ‘appropriate’ tannins in grasses; however, this was given a high priority in legumes. These criteria, and the desirability of reducing the extent of protein degradation in the rumen are discussed in relation to comments made by panel members.
Predicting the digestibility of grass grown for first‐cut silage
Authors: THOMPSON N. , KEILLER P. R. , YATES C. W. 
Published: April 2006

AbstractMeteorological factors influencing the temporal changes of digestibility of grasses in spring and early summer are discussed. Annual observations in England of the digestibility of three grasses are then related to the relevant meteorological variables using two multiple regression analysis methods. The resulting regression relationships are tested on independent data, and finally sets of regression coefficients are recommended for predicting from synoptic meteorological data the weekly progress of digestibility in different areas of England: a simplified set of regression relationships for predicting digestibility values a few days ahead which require forecasts of only temperature in order to be applied operationally is also given.
Changes in stubble carbohydrate content during regrowth of defoliated perennial ryegrass (Lolium perenne L.) on two nitrogen levels
Authors: GONZALEZ B. , BOUCAUD J. , SALETTE J. , LANGLOIS J. , DUYME M. 
Published: April 2006

AbstractChanges in stubble carbohydrate content during the regrowth of ryegrass (Lolium perenne L.) grown under hydroponic conditions at two nitrogen levels were studied as a function of time by high‐performance liquid chromatography. Experimental data showed that regrowth at a non‐limiting nitrogen level (1·0 mol m−3 NH4NO3) involved two different physiological periods. The first occurred during the first 6 d and was characterized by the mobilization of 60 to 90% of the soluble carbohydrates (i.e. glucose, fructose, sucrose, oligofructans and polyfructans). During the second period (6.28 d of regrowth) carbohydrate contents rose to the values observed prior to cutting (20% of dry matter at the 28th d of regrowth).The effect of low nitrogen conditions (0·2 mol m−3 NH4NO3) was observed only during the second phase. Plants regrown in a nitrogen‐starved medium accumulated 2·3‐fold more polyfructans than plants regrown in a non‐limiting nitrogen medium. Their fructose and glucose contents remained at 2% of dry matter from the end of the first phase of mobilization.The experimental results are interpreted and discussed in terms of the existence of two distinct fructan synthetic pathways.
Herbage productivity of a range of grass species under a silage cutting regime with high fertilizer nitrogen application
Authors: FRAME J. 
Published: April 2006

AbstractThe productivity of fourteen grasses was measured under a silage cutting regime of four harvests per year for 3 years (1984‐86) with an annual fertilizer N rate of 360 kg ha−1, applied at 120, 100, 80 and 60 kg ha−1 for successive harvests. The grasses were: red fescue (Festuca rubra)cvs Reptans, Dawson and Ruby, perennial ryegrass (Lolium perenne)cvs Perma and Sprinter, Yorkshire Fog (Holcus lanatus)commercial types I and II, smooth meadow‐grass (Poa pratensis)cvs Parade and Arena, creeping bentgrass {Agrostis stolonifera)cv. Penncross, crested dogstail {Cynosurus cristatus)cv. Southlands and rough meadow‐grass (Poa trivialis)cvs Dasas, Omega Øtofte and Sabre.Red fescue gave the highest dry‐matter (DM) production over the 3 years but because of low organic matter digestibility (OMD), its production of digestible organic matter (DOM) was lower than that of perennial ryegrass. Rough meadow‐grass was relatively low yielding in the first year and did not persist thereafter. Three‐year mean DM production ranged from 9‐22 kg ha”’(crested dogstail) to 14‐37 kg ha‐1 (red fescue cv. Reptans), while mean annual OMD values ranged from 0‐660 (smooth meadow grass cv. Arena) to 0766 (ryegrass cv. Sprinter). The mineral composition (P, K, Ca and Mg) differed among species; creeping bentgrass, crested dogstail, perennial ryegrass and Yorkshire fog had moderate to high mineral concentrations while smooth meadow‐grass had low concentrations. Mean two‐year (1985‐86) mineral composition (g kgDM−1) ranged from 3‐1 to 40 (P), 234 to 31‐0 (K), 3‐8 to 6‐0 (Ca) and 1‐6 to 2‐6 (Mg),It was concluded that while red fescue and Yorkshire fog showed considerable potential for silage DM production, there is scope for breeding red fescue cultivars with improved digestibility and more winterhardy Yorkshire fog; characterization of their ensiling qualities would also be useful.
Estimating biomass of an improved pasture using SPOT HRV data
Authors: WILLIAMSON H. D. 
Published: April 2006

AbstractSPOT high‐resolution visible (HRV) multispectral data were used to estimate the biomass of an improved pasture near Clare in South Australia. The study examined the effects of trees, senescent vegetation, surface wetness, herbage composition and management practices including the age of the pasture and stocking rate, on reflectance. This was undertaken by a comparison of spectral responses and through the use of partial correlation analyses. Changes in biomass had the greatest influence on reflectance, though the presence of trees and senescent vegetation influenced reflectance significantly in all wavebands. These areas were excluded from the model developed to estimate pasture biomass. The regression model was inverted and applied to a normalized difference SPOT HRV image. The accuracy of the biomass estimation was 43–81% at the 95% confidence level, or ±57.0 gm−2 of dry grass. This technique provides resource managers with a tool for routinely assessing pasture condition over large areas.
The effect of dry matter content on the preservation of big hale grass silages made during the autumn on commercial farms in South Wales 1983‐87
Authors: HAIGH P. M. 
Published: April 2006

AbstractA total of eighty‐nine big‐bale (BB) silages made on commercial farms in South Wales during the autumn in 1983‐87 were analysed to discern the effect of dry matter (DM) content on fermentation. Silages were made predominantly in late September, during fine weather from permanent pasture or perennial ryegrass pastures, which had not been grazed for 9 weeks. On average 7·8 ha of pasture were cut; most farmers attempted to pre‐wilt grass for an average of 36 h prior to ensilage in individual plastic bags. Silage making was usually completed within 4 d of starting to cut. Silage ammonia‐N content was inversely correlated with DM content. The results indicated that a DM content of about 280 g kg−1 was needed to produce well‐preserved silage with an ammonia‐N content of 100 g (kg total N)−1. Silages were, therefore, generally poorly preserved because the DM increase from wilting was only 2·3 g kg−1 h−1.
The effect of formic acid on the rate of water loss from cut grass and lucerne
Authors: JONES L. 
Published: April 2006

AbstractThe drying rates of grasses and lucerne, following treatment with 1% formic acid, were compared with those of untreated crops. Material was fully exposed to a flow of air in a ventilated laboratory oven set at 23 °C. Treatment with formic acid initially enhanced the rate of drying of grass, but this was followed by retardation. This reduction in the rate of drying was caused by the rapid desiccation of laminae, which reduced their effectiveness in providing a pathway for water loss from the stem. The rate of water loss directly from the stem surface was not increased by formic acid treatment, probably because the enveloping leaf sheaths acted as a protective layer. In contrast, formic acid increased drying rate in lucerne. whose stems have no such protective layer. The results suggest that chemical desiccants. which have a contact action are unlikely to have any application in making hay from grass.
Yield and nitrogen utilization by Lolium perenne and Trifolium repens on a limed stagnohumic‐gley soil in a pot experiment
Authors: HOPKINS D. W. , SHIEL R. S. , O'DONNELL A. G. 
Published: April 2006

AbstractIn a pot experiment the pH of a hill peaty soil was adjusted to cover the range 3.8 to 6.8 with Ca(OH)2. Yield and N content of the harvested plant material was greatest at pH 6.8 in pots sown with only Lolium perenne, and greatest at soil pH 6.1 in pots sown with Trifolium repens and L. perenne. T. repens established only at soil pH between 4·3 and 6·1. A small reduction in sward yield and a large and highly significant decrease in total N recovered by the harvested material, which occurred with increase in soil pH from 3·8 to 4·3, was attributed to a combination of increased N immobilization in the soil microbial biomass and to the poor performance of both sown and self‐propagating indigenous species around pH 4·3.