bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of a straw/concentrate mixture with silage as a buffer feed for grazing dairy cows
Authors: ROBERTS D. J. , KELLY E. F. 
Published: April 2006

AbstractOver a 24‐week period during the 1986 summer, three groups of January‐ to March‐calving dairy cows were either grazed conventionally (G) or grazed between morning and afternoon milkings and housed overnight and offered grass silage (Si) or a straw/concentrate mixture (St) ad libitum. The straw/concentrate mixture contained proportionately, 0‐33 long barley straw, 0·28 ground barley, 0·12 soya bean meal, 0·25 molaferm and 0·22 minerals. The metabolizable energy (ME) and crude protein (CP) contents of the silage fed in weeks 1‐8 and weeks 9‐24 were 9‐5 and 10−6 MJ kg MD−1 and 160 and 191 g kg DM−1 respectively. The straw mix had an ME content of 10−1 MJ kg DM−1 and CP content of 134 g kg DM−1. Partial storage feeding with silage or a straw/concentrate mixture led to a decrease in estimated herbage DM intake. The feeding of the straw/concentrate mixture increased total DM intake, but the estimated total ME intake was similar for treatments G and St. The intakes (kg DM d−1) for treatments G, Si and St were respectively, herbage 11·7,6·8,4·1; total l3·5,13·6,15·0; total ME intake (MJd−1) 163, 155, 163.Animal performance was, for treatments G, Si and St respectively: milk yield (kg d−1) 19·2, 17·5, 19·1 (s.e.d. 0‐87); milk fat content (g kg−1) 36·9, 37·6, 37.1 (s.e.d. 1.22); milk protein content (g kg−1) 35·3, 32·9, 33·4 (s.e.d. 0·76).
The economic consequences of integrating whole‐crop wheat with grass production on dairy farms in the UK: a computer simulation
Authors: DOYLE C. J. , MASON V. C. , BAKER R. D. 
Published: April 2006

AbstractHarvesting techniques, which involve simultaneously preserving and upgrading mature crops of whole cereals using an alkali, have been developed. When treated crops have been fed to sheep and cattle, satisfactory intakes and growth rates have been observed. With the possibility of falling cereal prices, such an end‐use for grain crops may be attractive in the future. Accordingly, a mathematical model of the production, harvesting and utilization of whole‐crop wheat and grass silage has been developed to examine the economic implications. Using the model, the comparative costs of growing and feeding alkali‐treated whole‐crop wheat in place of grass silage for winter milk production have been examined.A milk production system based on whole‐crop wheat rather than grass silage is estimated to improve profits by up to £130 per cow. However, the improvement in profitability is very sensitive to assumptions about the uses for surplus land or silage arising from such a switch. Furthermore, for physiological reasons it may be prudent to restrict the quantity of whole‐crop wheat fed to about 50% of the total forage intake. Thus, whole‐crop cereals may best be seen as a complement to rather than a substitute for grass silage. However, in the absence of data on feeding dairy cows with treated wheat silage, research is required before the computer simulations can be corroborated.
Pattern of interspecific tiller defoliation in a mixed‐grass prairie grazed by cattle
Authors: HEITSCHMIDT R. K. , BRISKEt D. D. , PRICE D. L. 
Published: April 2006

AbstractPermanently marked tillers of five perennial grasses, native to the mixed‐grass prairie of North America, were monitored to determine patterns of defoliation, architectural attributes influencing probabilities of defoliation. and post‐defoliation responses. Frequency of tiller defoliation was greatest for one of the dominant midgrasses, intermediate for the remaining midgrass and two dominant shortgrasses. and least for the subdominant midgrass. Midgrass species, including the infrequently grazed subordinate species, were consistently grazed more intensively than the shortgrass species. However, the relative intensity of defoliation did not vary among species or grazing periods indicating that intensity of defoliation was primarily a function of pre‐defoliation tiller height. Tiller architecture, including height, lamina number and the presence of reproductive culms, did not significantly influence frequency or intensity of defoliation within a species. The lack of evidence supporting tiller architecture as a selection criterion within a species suggests that animals were selecting on vegetation parameters at higher levels of vegetation organization than individual tillers. Grazed tillers of the three midgrasses exhibited greater relative rates of tiller elongation between grazing periods than non‐grazed tillers, particularly early in the season when environmental conditions for growth were most favourable. The patterns of interspecific tiller defoliation observed in this study parallel the long‐term patterns of grazing‐induced species replacement observed in this grassland.
Intake and behaviour responses by sheep to changes in sward characteristics under continuous stocking
Authors: PENNING P. D. , PARSONS A. J. , ORR R. J. , TREACHER T. T. 
Published: April 2006

AbstractPerennial ryegrass pastures were maintained at sward surface heights (SSH) of 30, 60, 90 and 120 mm by continuous variable stocking using lactating ewes and their twin lambs in spring and non‐lactating (dry) ewes in autumn.The effects of SSH on ingestive behaviour, herbage intake, animal performance and sward structure and production were measured in spring, and again in autumn, when an additional SSH of 20 mm was also established.In spring, differences in sward structure were quickly established with mean tiller numbers of 41 000, 30 000, 21 000 and 19 000 m−2 and leaf area indices (LAI) of 1·5, 2·2, 3·3 and 4·1 at SSH of 30 to 120, respectively. By autumn the mean tiller numbers had fallen to 26 000, 26 000, 23 000, 18 000 and 13 000 m−2 and LAI to 1·0, 1·1, 1·5. 2·0 and 1·5 for treatments 20 to 120.The mean stocking rates for the ewes in spring were 27, 20, 22, and 19 ewes ha−1 and growth rates of their lambs were 208, 275, 250 and 263 g d−1 for treatments 30 to 120. In autumn the stocking rates maintained for dry ewes were 22, 15, 9, 4 and 0 for treatments 20 to 120.In spring, both grazing times (GT) and prehension biting rate (BR) were negatively correlated with SSH, while bite mass (BM) was positively correlated with SSH. However, mean daily intakes of organic matter (OM), were reduced only for animals grazing the 30 mm sward.In autumn, intake rate was lower only for the animals grazing the 20mm sward and GT and BR were not significantly affected by SSH.Relationships between SSH and, components of ingestive behaviour and intake, are presented and the control mechanisms involved are discussed. The results showed that the optimum sward surface height for continuously stocked swards, grazed by sheep, Was between 30 mm and 60 mm.
Prediction of the nutrient content of botanical fractions from annual legumes by near‐infrared reflectance spectroscopy
Authors: STIMSON C. , KELLAWAY R. C. , TASSELL R. J. , ISON R. L. 
Published: April 2006

AbstractProcedures used to determine chemical composition and digestible organic matter in dry matter (DOMD) are slow and expensive. The possibility of using near‐infrared reflectance spectroscopy (NIRS) as an alternative procedure was investigated with annual legumes. Material from cultivars of Medicago murex, Trifolium balansae, T. resupinatum and T. subterraneum was harvested soon after plants had matured. Samples were sorted into stem, leaf and burr fractions and analysed chemically and by NIRS. Data were then sorted into two similar sets, one of which was for calibration and the other for validation. Data for each chemical fraction, in samples used for calibration, were regressed sequentially against the corresponding reflectance spectral data, the log of there reciprocal of which was transformed to first or second derivatives. Equations of best fit were then used to predict the composition of samples in the validation set.Standard errors of calibration and validation respectively, expressed as percentages of the mean, were 0·5 and 0·6 for dry matter (DM), 2·0 and 2·6 for organic matter (OM), 4·8 and 4·3 for DOMD, 6·0 and 7·2 for crude protein, 4·1 and 4·4 for acid‐detergent fibre (ADF), 2·5 and 3·1 for neutral‐detergent fibre (NDF) and 8·9 and 10·9 for lignin.
Laboratory studies on the effect of potassium carbonate solution on the drying of cut forage
Authors: JONES L. 
Published: April 2006

AbstractThe potential drying rate of cut forage grasses and legumes, following treatment with a 2% potassium carbonate (K2CO3) solution, were compared with those of untreated crops under laboratory conditions. Material was fully exposed to a flow of conditioned air (20°C; 50% relative humidity). Treatment with K2CO3 had little effect on the drying rate of a range of cultivated grass species. The drying of legume species, particularly lucerne was accelerated. The average reduction in lucerne drying time, following K2CO3 treatment, was 63% and was similar for a range of varieties. The differential drying of lucerne leaf and stem fractions was reduced following treatment, and reduced further by selective treatment of the stem. Potassium carbonate treatment was superior to traditional mechanical conditioning for accelerating water loss from cut lucerne. The practical implications are discussed.
The long‐term effects of a range of pasture treatments applied to three semi‐natural hill grassland communities.
Authors: COMMON T. G. , HUNTER E. A. , EADIE J. , FLOATES M. J. S. , HODGSON J. 
Published: April 2006

AbstractFive pasture treatments were applied to three semi‐natural hill grassland communities. The pasture treatments were: (1) controlled grazing, (2) controlled grazing + lime, (3) controlled grazing + lime + phosphate, (4) controlled grazing + lime + phosphate + oversown white clover and (5) controlled grazing + lime + phosphate + oversown white clover + oversown perennial ryegrass. The communities were dominated by Agrostis/Festuca (site 1), Molinia (site 2) and Nardus (site 3). The Nardus at site 3 was substantially reduced by herbicide before treatments were applied. All treatments were grazed simultaneously by mature wether sheep on three occasions each year to a residual herbage mass of 560 kg DM ha−1. There were two grazing periods, each of 4 weeks duration, beginning in mid‐May and mid‐July respectively and a further grazing period of 3 weeks duration beginning in mid‐October. The number of sheep grazing days and liveweight gain of sheep were recorded during each grazing period for 13 years at each site. Organic matter intake (OMI) and digestibility (OMD) of ingested herbage were measured in years 2, 5 and 13.Mean daily OMI per head ranged from 1290 g for treatment 1 to over 1400 g for treatments 4 and 5. OMI values were higher for the Agrostis/Festuca site (mean OMI 1450 g) than for the Molinia and Nardus sites (1310 g and 1370 g respectively) largely owing to differences in the values for treatments 1, 2 and 3. OMI values for each treatment decreased by around 300 g between May and October.Mean OMD values from treatments 1, 2 and 3 were higher for the Agrostis/Festuca site (0·66) than for the Molinia and Nardus sites (0·63 and 0·64 respectively). The OMD values for treatments 1, 2 and 3 at the Molinia and Nardus sites declined by between 0·05 and 0·02 between years 2 and 13 and also showed the greatest decrease between May and October (0·08). OMD values for treatments 4 and 5 (0·67 and 0·69 respectively) were higher than for treatments 1, 2 and 3 at all sites and levels were maintained over 13 years.Individual liveweight gains of sheep increased from treatment 1 (−18 g d−1) to treatment 5 (82 g d−1), but they decreased over time on all treatments.The Agrostis/Festuca site gave 17% more annual sheep grazing days than the Molinia site and 33% more than the Nardus site. The mean number of annual sheep grazing days for each treatment ranged from 2250 for treatment 1 to 3640 for treatment 5. Annual sheep grazing days increased over 13 years by between 35 and 45% for treatment 1 and 55 and 70% for treatment 5.The results are described in relation to the changes in pasture composition and herbage accumulation.
A model of aerobic fungal growth in silage.
Authors: MUCK R. E. , PITT R. E. , LEIBENSPERGER R. Y. 
Published: April 2006

AbstractThe components of a simulation model of mesophilic and thermophilic yeast and mould growth in aerobically deteriorating silage are presented. The purpose of the model is to examine the relative roles of yeasts and moulds in deterioration and the factors affecting aerobic stability. Information for the model was based on literature studies. Growth of the fungi was assumed to be affected by temperature, pH, water activity, and lactic and acetic acid concentrations. The substrates utilized in the model, in order of preference, were water‐soluble carbohydrates, ethanol, lactic acid and acetic acid. Gas movement and heat transfer were not considered. Consequently, oxygen and carbon dioxide concentrations were assumed to be those for open air, and the heat of respiration retained in the silage was set as a constant percentage of that released by fungal growth.Based on the relationships developed for the model, pH affects yeast growth minimally and does not affect mould growth at all. Water activity over the range in silage affects yeast growth more than mould growth, but affects neither one strongly. Undissociated lactic and acetic acids decrease growth rate and may be important factors in silage stability. Compared with moulds, yeast growth rates are less affected by suboptimum temperatures but are more sensitive to temperatures in excess of the optimum.A succeeding study compares the model with published aerobic deterioration studies and examines the predicted succession of microbial groups and the variation in silage stability as affected by silage parameters, initial temperature, and initial microbial populations.
Primary growth and quality characteristics of Bromus willdenowii and Lolium multiflorum
Authors: HUME D. E. 
Published: April 2006

AbstractPrairie grass (Bromus willdenowii Kunth) and a tetraploid Westerwolds ryegrass (Lolium multiflorum Lam.) were established in a field trial in April 1987 and grown for a 3‐month period of undisturbed growth. During this period the biomass partitioning and forage quality of each plant component was compared for the two species. Leaf, tiller and plant populations were assessed on ten occasions while accumulation of herbage and roots, chemical composition, leaf area and light interception were determined on six occasions. Herbage was divided into leaf lamina, inflorescence, vegetative and reproductive pseudostem. Nitrogen, water‐soluble carbohydrates, ash, cell wall and in vitro digestibilities were determined.Prairie grass had lower plant, tiller and leaf populations but larger tillers and more live leaves per tiller than Westerwolds ryegrass. Both species had similar light interception and leaf area index. Roots were distributed more evenly and to greater soil depths in prairie grass. Leaf lamina made major contributions to herbage DM accumulation and accumulation of the various chemical components, but as reproductive development occurred, reproductive pseudostem became a major component of the total sward. Harvesting herbage to gain optimum quantities of DM, herbage quality and regrowth is discussed. It is concluded that prairie grass is a high‐yielding, high‐quality forage grass, comparable with Westerworlds ryegrass.
Differences in the vertical distribution of plant material within swards continuously stocked with cattle
Authors: GIBB M. J. 
Published: April 2006

AbstractA mosaic of short, frequently grazed areas and tall, infrequently grazed areas is a characteristic of swards continuously stocked with cattle. Inclined point quadrat measurements were used to compare sward structure on the frequently and infrequently grazed areas in an experiment on mixed grass/clover swards with beef cattle, in which the swards were maintained at overall mean rising‐plate target heights of 3·0, 5·5 or 7·0 cm. The results demonstrate large within treatment differences in the vertical distribution of plant parts between the frequently and infrequently grazed areas, and smaller differences within these areas between treatments. The consequences of these observations and the need for greater effort in recording the detailed structure within these areas in grazing experiments is noted.
Effect of sward surface height on the performance of ewes and Iambs continuously grazed on grass/clover and nitrogen‐fertilized grass swards
Authors: CHESTNUTT D. M. B. 
Published: April 2006

AbstractIn three successive years, sward height was maintained at 3, 5, 7 or 9 cm on grass swards receiving a total of 300 kg N ha−1 in six equal monthly dressings from April, and on grass/clover swards receiving 50 kg N ha−1 as a single dressing in early spring. From turnout in April until weaning in July, 64 ewes and their lambs (mean litter size 1·5) were continuously grazed at the four sward surface heights on the two sward types. White clover content of grass/clover swards remained low throughout the experiment ranging from 0·2 to 7·4% of the herbage mass. During the first two years, lamb gains averaged over sward types were 204, 260, 285 and 308 g d−1 up to weaning, while in the third year gains were 238, 296, 296 and 260 g d−1 on 3, 5, 7 and 9 cm swards respectively. Ewes lost live weight on 3 cm swards but apart from this sward height had little effect on performance. During the autumn, weaned lambs gained — 27, 87, 147 and 167 g d−1 on 3, 5, 7 and 9 cm swards respectively. Sward type had only a small effect on the performance of lambs up to weaning but in the autumn, mean gains of weaned lambs were lower on grass/N swards (73 g d−1) than on grass/clover swards (115 g d−1). Relative to 3 cm swards, carrying capacities of 5, 7 and 9 cm swards were 0·76, 0·57 and 0·52 respectively from turnout to weaning and 0·66, 0·52 and 0·44 respectively during autumn. Grass/clover swards carried 0·67 of the ewes carried by grass/N swards from turnout to weaning and 0·51 of the live weight carried by grass/N swards during autumn.The reaction of the two sward types to sward height did not appear to differ but in the third year there was evidence of a reduction in white clover content when swards were grazed at 9 cm. The data suggest that lamb growth rates will increase as sward height increases up to 9 cm and the evidence for this was stronger with weaned lambs in autumn than with suckling lambs in spring.
Protein supplementation of formic acid‐ and enzyme‐treated silages. 2. Nitrogen and amino acid digestion
Authors: JACOBS J. L. , McALLAN A. B. 
Published: April 2006

AbstractTwo silages were made from primary growth perennial ryegrass and ensiled after the application of either formic acid or an enzyme mixture of cellulase and hemicellulase. Silage analysis showed both silages to be well preserved with low pH of 3·70 and 3·62 for the formic and enzyme treatments respectively. Formic acid‐treated silage had a higher total amino acid concentration than enzyme‐treated silage. The silages were offered to growing steers either as the sole diet or supplemented with rapeseed meal at 60 g or 120 g fresh weight kg−1 silage DM offered, in a 6 × 6 Latin square arrangement.Non‐ammonia nitrogen and microbial nitrogen flows at the duodenum (g d−1) were significantly (P < 0·05) increased by supplementation of enzyme‐treated silage compared with formic acid‐treated silage (enzyme, 83·6, 58·7; enzyme + 60 g, 101·7, 75·3; enzyme + 120 g, 112·5, 80·7; formic, 91·9, 63·7; formic + 60g, 88·3, 67·9; formic + 120 g, 95·5, 67·1) respectively. Efficiencies of microbial protein synthesis were increased for supplemented enzyme‐treated silage diets and values were reduced for supplemented formic acid‐treated silage diets compared with the silage only diets (enzyme, 27·9; enzyme + 60 37·7; enzyme + 120 g, 38·6; formic, 33·7; formic + 60g, 31·2; formic + 120 g, 28·8). Total amino acid flow at the duodenum increased with supplementation of both silages; however, microbial amino acid flow increased significantly (P < 0·05) with supplementation of enzyme‐treated silage compared with formic acid‐treated silage diets. Significantly greater amounts of cystine, methionine, alanine, valine and aspartic acid entered the small intestines of animals receiving supplemented enzyme silages compared with supplemented formic acid silages.
Oesophageal fistulated cattle can give unreliable estimates of the proportion of legume in the diets of resident animals grazing tropical pastures
Authors: JONES R. J. , LASCANO C. E. 
Published: April 2006

AbstractEstimates of the diet of resident intact steers grazing four different tropical grass/legume pastures were made by two methods. In the first, oesophageal fistulated (OF) steers were used on three days and the botanical composition of the extrusa determined microscopically. The second method measured the carbon ratio (δ13C) of the faeces of the resident steers over three days, and the percentage legume in the diet was calculated after correction for digestibility differences between the grass and legume components. Estimates of legume percentages in the diet by the two methods differed markedly; OF steers selected a diet containing much more legume than did resident steers, the regression of extrusa estimates on δ13C having a negative slope.This, and other evidence, clearly shows that estimates using OF steers of the diet of resident cattle grazing tropical grass/legume pastures can be most unreliable. Reasons for this unreliability are briefly discussed.
The effect of timing and rate of potash application on the yield and herbage composition of grass grown for silage
Authors: DAMPNEY P. M. R. 
Published: April 2006

AbstractReplicated field trials were carried out at 23 sites in England and Wales between 1986 and 1988 examining the response of first‐cut grass silage to different levels of early winter‐ or spring applied potash on dry matter (DM) yield and herbage composition. Residual effects at the second cut were measured. In 1986/87 and 1987/88, the effect of additional potash at second cut was examined.Yield responses at first cut were measured at 13 sites (P<0·05). Optimum potash rates (K‐opt) ranged from 0 to over 160 kg ha−1, the highest rate tested. The mean rate of response up to K‐opt at responsive sites was 10·4 kg DM (kg K2O)−1. Herbage K% increased with potash rate regardless of the requirement for maximum economic yield. Increasing potash rate reduced herbage Mg% by less than 0·020% which was less than the effect of soil Mg level. An increase of 50 mg 1−1 in soil Mg (0‐7·5 cm depth) increased herbage Mg by 0·034%. Early winter application of potash was generally as effective as spring application though it gave slightly lower herbage K and higher herbage Mg concentrations. Offtake of potash (K2O) at first cut was on average 12 kg ha−1 more from spring than from early winter application.Herbage analysis for N:K ratio was the best indicator of potash requirement. Regression analysis of the N:K ratio of herbage in control (nil potash) treatments against K‐opt at first cut gave an r2 value of 51·4% (***). For herbage total K%, r2 was 39·7% (**) and for soil K (0‐7·5 cm depth) it was 21·3% (*). Taking account of soil K below 7·5 cm depth was important at some sites, particularly those with a history of arable cropping and associated soil cultivation.Residual effects of a single early winter or spring application were measured, but additional potash applied for second cut was generally more effective. Optimum rates of potash for second cut were not determined.