bluuebunny/crossref_metadata_2025 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

Over 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

Harvesting 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

Permanently 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

Perennial 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

Procedures 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

The 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

Five 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

The 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

Prairie 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

A 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

In 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

Two 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

Estimates 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

Replicated 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.
Effect of ryegrass endophyte in mixed swards of perennial ryegrass and white clover under two levels of irrigation and pesticide treatment
Authors: LEWIS G. C.
Published: April 2006

In a small‐plot experiment at Hurley, UK, infection of perennial ryegrass with the endophytic fungus Acremonium lolii had no apparent effect on seedling populations and herbage yield of ryegrass and white clover sown in mixture. The plots were maintained under two levels of irrigation with or without pesticide (carbosulfan granules) to study possible interactions with stress due to drought or pest damage. The higher level of irrigation consistently increased yield of both grass and clover during 1989 and 1990, but the effects of endophyte and pesticide on yield were not consistent, nor were the few significant interactions between factors. It is concluded that infection of ryegrass does not appear to increase ryegrass production or to decrease white clover production in the UK, in contrast to reports from New Zealand.
The use of frequency estimates in studying sward structure
Authors: NEUTEBOOM J. H. , LANTINGA E. A. , VAN LOO E. N.
Published: April 2006

Estimates of the frequency of absence of rooted perennial ryegrass tiller bases from concentric sampling quadrats of different sizes are recommended for characterizing the open space structure of perennial ryegrass swards. It is proposed that these estimates are useful for evaluating the persistence of grass species and cultivars in swards. Data on this aspect of sward structure could provide criteria for the productivity of a sward and thus for the need to reseed grassland.
The influence of surface and sub‐surface application methods for pig slurry on herbage yields and nitrogen recovery
Authors: REES Y. J. , PAIN B. F. , PHILLIPS V. R. , MISSELBROOK T. H.
Published: April 2006

Experiments were conducted on a grassland site at Wrest Park, Silsoe, Bedfordshire between 1987 and 1989, to compare herbage yields from slurry applied by deep and shallow injection, low trajectory and conventional vacuum tanker methods. Slurry application rates for all spreaders were calibrated at 86 ± 5 t ha‐1, an equivalent of c. 200 kg NH4+‐N ha‐1 applied in autumn or in spring.

As expected, herbage yields following spring applications were higher than from autumn applications, with average mineral fertilizer equivalents of 122 and 89 kg N ha‐1 respectively. Yields from the conventional and low trajectory spreaders showed no consistent differences. However, in both years, first cut yields from plots were significantly lower (P < 0·05) where slurry had been injected than where surface applications had been used by an average of 0·7 t DM ha‐1. Subsequent cuts in 1988 demonstrated higher residual effects from injection so that annual total yields were similar from all slurry applications irrespective of spreader type.

Analysis of N content revealed high N levels in herbage from deep injection plots. Mean concentrations of N in the herbage, expressed as a percentage of the dry matter, were 1·43 for surface treatments and 1·79 for deep injection in 1988, and 1·84 for surface treatments, 2·13 for shallow injection and 2·68 for deep injection in 1989.
Ensiling peas, ryegrass and wheat with additives of lactic acid bacteria (LAB) and cell wall degrading enzymes
Authors: WEINBERG Z. G. , ASHBELL G. , AZRIELI A. , BRUKENTAL I.
Published: April 2006

The effect of applying a commercial inoculum (at 1.5 × 105 cfu g‐1) containing Streptococcus faecium (Lacticil M74®. Medipharm, Sweden), and cell wall degrading enzymes (Celluclast® and Viscozyme®, Novo, Denmark) to pea, ryegrass and wheat silages was studied under laboratory conditions. Celluclast was applied at 0.03 Novo Cellulose Units (NCU) and Viscozyme at 0.024 Fungal β‐glucanase (FBG) per g fresh crop. The peas and wheat used were at three stages of maturity, and the ryegrass used was either direct‐cut or wilted. This yielded a wide range of dry matter (DM) and fibre content.

Inoculum use improved the ensiling process of most of the forages tested, as indicated by a faster and greater decrease in pH, and by a faster and larger build‐up of lactic acid. Inoculum, however, lowered the aerobic stability of wheat silages. The addition of the enzymes alone did not affect the ensiling process. In silages of peas and wheat at the flowering stage, the combination of inoculum and enzymes resulted in a improvement to the ensiling process, as compared with inoculum only.

The combined treatment of inoculum and enzymes resulted in a lower percentage of neutral detergent fibre (NDF) and acid detergent fibre (ADF) in the silages of the flowering peas and of the direct‐cut ryegrass. The NDF and ADF contents in the inoculum plus enzyme‐treated pea silages made at the flowering stage were 322 and 296 g kg‐1, compared with 365 and 327 g kg‐1 in the control silages. The NDF and ADF contents in the silages made from the direct‐cut ryegrass were 312 and 205 (treated with inoculum plus enzymes) vs 383 and 257 g kg‐1 (control). However, the DM rumen digestibility of the silages was not improved by any of the treatments.

It is concluded that a suitable inoculum could be beneficial to the ensiling process. The benefit expected from the application of cell wall degrading enzymes to silages is as yet unclear.
Improvement in soil structure associated with white clover
Authors: MYTTON L. R. , CRESSWELL A. , COLBOURN P.
Published: April 2006

Observations have been made which suggest that clover is more effective than ryegrass in developing rapid improvements in soil structure. To test this hypothesis, grass, grass/clover and clover swards were grown in undisturbed field cores. Significant differences in drainage rates and plant biomass production, and visible changes in soil structure, all supported the hypothesis that clover improves structure rapidly, but there were no significant differences in bulk density, porosity or aggregate stability between the treatments. Soil moisture characteristic curves of soil/peat/grit compost planted with grass, grass/clover or clover and grown for two years indicate that a more free‐draining structure develops under clover than under grass due to a higher ratio of macro‐ to micropores.
The response of a ryegrass sward to wheel traffic and applied nitrogen
Authors: DOUGLAS J. T. , CRAWFORD C. E.
Published: April 2006

The dry matter and nitrogen yield and estimated metabolizable energy of perennial ryegrass grown for silage were recorded from 1988 to 1990 for three levels of wheel traffic (zero, light and severe) at four rates of nitrogen fertilizer. The traffic treatments were applied by tractor wheels in the spring and summer of 1987 and in the spring of 1988 and 1990. First‐harvest yields were reduced consistently by severe traffic: for example, at a rate of 100kg N ha‐1, dry matter (DM) produced in the severe treatment was 58, 72 and 84% of that in the zero traffic treatment in successive years. Wheel traffic effects on yield were markedly smaller at second and third cuts than at first cut. Nitrogen uptake and apparent recovery of fertilizer nitrogen were usually less after the relatively severe traffic treatment than after zero or light traffic treatments. Denitrification fluxes, measured in the second and third years, indicated that gaseous losses of nitrogen were largest when soil compaction was greatest.

Reduction of herbage yield at first cut in 1989, the year in which no wheel traffic had been applied at the start of the growing season, indicated that impaired soil physical conditions were implicated, quite apart from possible damage to the grass plants. Soil structure was damaged in both light and severe traffic treatments: in the latter, the volume of air‐filled pores during the wetter periods early in each growing season was especially small (<4%, v/v). It seemed likely, therefore, that poor aeration was a key factor in limiting both grass growth and nitrogen utilization.

The effect of wheel traffic on herbage production tended to decline over the 3‐year period of the experiment. However, it was not clear whether that trend was primarily a consequence of a progressive improvement in the structure of the most dense soil, or was a degree of variation caused by differences in weather patterns between years.
The effect of offering a brewers grains/treated straw supplement to grazing dairy cows
Authors: LEAVER J. D. , CAMPLING R. C.
Published: April 2006

In a two‐year study, set stocked dairy cows were offered a mixture of brewers grains and sodium hydroxide‐treated straw (1:1 on a dry matter basis)for 1 h daily. The experiments lasted for 20 and 19 weeks, mean supplementary (buffer) feed dry matter intakes were 3·0 and 3·4 kg d‐1 and mean sward heights (rising plate meter) were 4·9 and 4·7 cm in 1988 and 1989 respectively. The control group received no supplementation. The buffer feed significantly increased milk yield (26·3 vs 24·6 kg d‐1 and 28·6 vs 26·3kg d‐1 in 1988 and 1989 respectively), increased liveweight gain (0·27 vs 0·13 kg d‐1 and 0·27 vs 0·17 kg d‐1) and increased effective stocking rate (5·17 vs 4·69 cows ha‐1and 5·10 vs 4·53 cows ha‐1). There were no significant effects on milk composition. The greatest responses in milk production were found in the late grazing season.
Growth and colonization of a range of white clover cultivars strip‐seeded into an upland perennial ryegrass sward
Authors: WILLIAMS E. D. , HAYES M. J.
Published: April 2006

Seven cultivars of white clover (Trifolium repens L.) (Kent, S184, Huia, Menna, Donna, Alice and Nesta) and a commercial mixture, ‘Ensign’, were strip‐seeded into an upland perennial rye‐grass (Lolium perenne L.) sward in late June 1986. Swards were first grazed by sheep, either on 5/6 August (early) or on 19/20 August (late) and then every 14–21 days (frequently) or 28–42 days (infrequently) during 1986, followed by a common grazing regime in 1987. During April to mid‐June 1988 the swards received either a moderate amount of nitrogen or none and were cut frequently or once only in mid‐June. Growth of individual seedlings was assessed before and after grazing during 1986 and stolon accumulation and distribution and sward colonization were assessed during 1987 and 1988.

All cultivars emerged rapidly and satisfactorily and there were no consistent significant differences in the overall dry matter accumulation per seedling during establishment. During the first autumn the proportion of the aboveground biomass removed during grazing was smallest in Kent (c. 20%) and largest in Nesta (c. 40%). Kent and S184 produced most leaves and stolons and the greatest length of stolons per seedling and per individual stolon, and Nesta and Alice the fewest leaves and stolons and shortest stolons. Seedlings grazed early had heavier and longer stolons than those grazed late; those grazed frequently had more leaves, stolons and growing points than those grazed infrequently, especially following early grazing.

During 1987 Kent and S184 had consistently the largest number of stolon growing points, and weight and length of stolons per unit area; these two cultivars and Nesta also colonized the sward more rapidly than the other cultivars. All cultivars contributed substantially and similarly to herbage production in late September. There were no residual effects of the 1986 treatments after the summer of 1987.

During 1988 additions of nitrogen fertilizer at 100 kg N ha‐1 or allowing the herbage to remain undefoliated between mid‐April and mid‐June both independently halved the number of stolon growing points per unit area; together they reduced it by 80%. Nitrogen also, on average, halved stolon weights but less so in Nesta, Alice and Huia and more so in all other cultivars. Infrequent defoliation greatly decreased stolon weights in Kent and S184 but had no significant effects on the other cultivars. Sward colonization was almost complete by June and entirely so by October for all cultivars in all treatments.

Implications of the results for the after‐management of strip‐seeded white clover are discussed.
A comparison of the output from permanent swards containing clover or receiving nitrogen fertilizer when continuously grazed by ewes and lambs
Authors: LAWS J. A.
Published: April 2006

A 2‐year experiment was designed to compare the output from a permanent grass sward, either containing clover (GC) or receiving 200kg N ha‐1 (GN), when continuously grazed by sheep stocked at 12 and 15 ewes ha‐1 on GC and 15 and 18 ewes ha‐1 on GN. Sward surface height (SSH) was controlled within designated guidelines by adjusting the size of the grazing area with an electrified ‘buffer’ fence; the herbage surplus to grazing requirement was cut and conserved. A dried grass supplement was offered to the sheep during periods of low herbage availability.

The experiment was carried out during 1989 and 1990. No silage was made on GC15 in either year compared with 28 and 90kg DM ewe‐1 on GN15 in 1989 and 1990 respectively; supplementation was consistently and significantly greater on GC15 than on GN15. Clover proportion was generally higher on GC12 than GC15 (significant (P <0·01) in September 1989) and reached a maximum level of 14%on GC12 in August 1990. Herbage organic matter digestibility was little affected by the inclusion of clover in the sward. Differences in lamb growth rate were not significant and, at the common stocking rate, there was no difference in lamb output between GC and GN.

In 1990, GC12 and GN15 treatments proved to be successful after weaning in balancing the increasing nutritional requirements of the ewes during the period prior to mating, the requirements of a declining lamb population as the lambs satisfied the criteria for slaughter and were sold, and a continuing need to conserve surplus herbage. The metabolizable energy requirements of the ewes and lambs over 2 years were 75·8 and 74· 7 GJ ha‐1 for GC15 and GN15 respectively, and the differences in total utilized metabolizable energy output of the two systems were due to the amounts of herbage conserved and supplement consumed. The 2‐year mean total UME output on GC15 was 80% of that on GN 15 (67·8 and 84·4 GJ ha‐1 for GC15 and GN15 respectively) and the experiment provided further evidence that grass/white clover swards with no fertilizer N applied are capable of producing about 80% of the total output of grass swards receiving 200 kg N ha‐1.
The influence of the radiation environment around the node on morphogenesis and growth of white clover (Trifolium repens)
Authors: THOMPSON L.
Published: April 2006

The growth of clonally propagated clover plants (Trifolium repens) in the glasshouse was compared with their growth under canopies of Tropaeolum peregonium with or without supplementation from red light emitting diodes (LEDs) directed at the youngest node bearing a fully expanded leaf. The T. peregonium was grown over a net support so that its roots did not meet those of the clover. A similar experiment was set up in a permanent grassland using canopy shade from various grass species (Holcus lanatus, Lolium perenne and Agrostis stolonifera) with and without supplementation. The LEDs increased the ratio of red to far red radiation (R/FR) received by the treated node with no apparent increase in photosynthetically active radiation (PAR) during the day.

The morphogenetic effects of canopy shading (notably fewer branched nodes and less well‐developed branches) were largely removed by supplementation so that the supplemented plants came to resemble those grown in full daylight, particularly in the glasshouse experiments. The results highlight the Importance of the radiation environment at the base of the canopy in the morphogenetic responses of plants to putative competition, and the data are consistent with the hypothesis that responses are communicated acropetally along the stolon.
Spring defoliation of white clover seed crops. 2. Potential harvestable seed yield and seed yield components of contrasting white clover cultivars
Authors: MARSHALL A. H. , HOLLINGTON P. A. , HIDES D. H.
Published: April 2006

The effects of different spring defoliation managements on potential harvestable seed yield and seed yield components of three contrasting white clover cultivars were assessed. The small‐leaved cv. S184 produced more but smaller inflorescences than the large‐leaved cv. Olwen and Menna, a medium‐leaved cultivar. Cultivar Olwen, however, produced more ripe and brown (nearly ripe) inflorescences with more florets, seeds per floret and a higher seed yield per ten inflorescences than the other cultivars. Potential harvestable seed yield and individual seed yield components were only influenced by defoliation after bud emergence, as defoliation before bud emergence had no effect on seed yield components. Defoliation after bud emergence had a similar effect on all cultivars: the number of ripe inflorescences was unaffected by defoliation but the number of brown and therefore harvestable (ripe + brown) inflorescences was highest following defoliation three weeks after bud emergence. Florets per inflorescence, seed per floret, 1000 seed weight, seed yield per ten inflorescences and potential harvestable seed yield were not influenced by defoliation after bud emergence. Season had a significant effect on seed yield components and influenced the effect of defoliation treatments, emphasizing the importance of climate in white clover seed production. The results are discussed in relation to the spring defoliation of white clover seed crops, harvesting techniques and the provision of guidelines for optimizing seed yield.
Impact of non‐corrosive forage stabilizer on chemical composition and storage characteristics of lucerne hay
Authors: DEETZ D. A. , HARRISON J. H. , EVANS D. W.
Published: April 2006

Three trials examined the impact on chemical composition, leaf‐stem ratio and bale temperature of applying a low‐acid stabilizer and a Lactobacillus fermentation product at baling lo moist (20–25% moisture) lucerne Medicago saliva L.) hay. Treatments evaluated were lucerne baled at: 17–20% moisture (dry control); 20–25% moisture with addition of 200 g or 400 g 100kg‐1 of a low‐acid stabilizer, with 4·1 ml or 8·1 ml 100kg‐1 of a Lactobacillus fermentation product; and 20–25% moisture with no treatment (wet control). In trial 1, low‐concentration acid treatment was effective in limiting the increase in bale temperature of moist hay. In trials 2 and 3, bale temperature for low‐concentration acid and Lactobacillus fermentation product‐treated hay was similar to untreated moist hay In trial 3, higher application rates of either product were not effective in further reducing bale temperature. In trials 1 and 3, levels of neutral detergent fibre, acid detergent fibre, acid detergent lignin and acid detergent insoluble nitrogen were higher for moist hay than dry control. Nitrogen levels tended to be higher for moist hay. Leaf‐stem data from trial 2 suggest that more leaves can be retained by baling relatively high‐quality (late bud maturity) legumes at 20–25% moisture. In some circumstances use of a low‐acid forage stabilizer for preservation of high‐quality lucerne can minimize increases in temperature during storage of hay baled while moist (20–25%).
The effects of concentrate energy source and protein content on milk production in cows given grass silage ad libitum
Authors: HUHTANEN P.
Published: April 2006

Sixteen Friesian cows were given four dietary treatments in a 4 × 4 Latin square experiment with a 2 × 2 factorial arrangement of treatments. The diets consisted of grass silage ad libitum plus 2 kg of hay per day and two types of concentrates of either barley or a mixture of barley, oats and fibrous by‐products [200,200 and 600 g per kg dry matter (DM) respectively], with two protein contents. For the low‐protein diets, barley‐ (B) and fibre‐based (F) concentrates were given without protein supplements, while for high‐protein diets 1 kg of both concentrates was replaced with fish‐meal (FM). The concentrates were given at the rate of 9kgd‐1 for the cows (n= 12) and 8kg d‐1 for the heifers (n= 4).

The cows given the F diets tended (P < 0·10) to have a greater silage dry matter intake and produced 1·5kg d‐1 more (P < 0·05) milk with a lower (P < 0·05) protein content than those given the B diets. Increasing dietary crude protein concentration with FM had no effect on feed intake but resulted in significant increases in milk yield (P < 0·01), milk protein content (P < 0·05) and yields of milk constituents. The response in milk yield to FM tended to be greater with barley than with fibrous supplement (+2·5 vs+ 1·5kgd‐1). Compared with B diets, the greatest relative increase occurred in lactose yield (0·07) when the corresponding F diets were fed, while FM produced the greatest response in protein yield (0·12). The calculation of the utilization of metabolizable energy (ME) for milk production showed that both the feeding of a concentrate consisting of different carbohydrate sources and inclusion of fish meal improved the utilization of ME, the effects being partially additive. It is concluded that the nutrient supply to the cow's tissues can be modified by the source of carbohydrate and protein supplementation as indicated by different responses in the yield of milk constituents. The production response to protein supplementation may depend on the source of carbohydrate in the concentrate.
Fermentation and nutritive value of Zea mays and lucerne forage ensiled with added rolled barley
Authors: HARRISON J. H. , KINCAID R. L. , LONEY K. A. , RILEY R. E. , CRONRATH J.
Published: April 2006

The effect of adding rolled barley on the ensiling characteristics and nutritive value of lucerne and corn (Zea mays) forage was studied using 19‐1 plastic mini‐silos. Other factors evaluated with lucerne were the effect of wilting and added lactic acid bacteria. Rolled barley was added at rates of 0, 50, 100 and 150gkg−1 (wet weight) to lucerne or corn forage. Lucerne was ensiled at 170–330 g kg−1 dry matter (DM) and lactic acid bacteria were applied at 105g−1 wet forage. Addition of rolled barley consistently improved the fermentation of lucerne by lowering the pH and decreasing the concentration of acetate and ammonia nitrogen. Wilting of lucerne had variable effects on fermentation in two experiments. The addition of lactic acid bacteria improved fermentation by decreasing the concentrations of acetate and ammonia nitrogen, improved the nutritive value by increasing the in vitro dry matter digestibility (IVDMD), and was associated with decreased amounts of lactic acid. Corn was ensiled at 250 g kg−1 DM, and added rolled barley had little effect on the fermentation of corn silage. The digestibility of all silages determined in vitro was improved by the addition of rolled barley.
Mineral composition of red clover treated with growth regulators in early spring
Authors: NARASIMHALU P. , KUNELIUS H. T.
Published: April 2006

The effect of growth regulators on mineral composition of red clover (Trifolium pratense L.) was assessed in two growing seasons, daminozide {butanedioic acid [mono(2,2‐dimethylhydrazide)]} or mefluidide [N‐(2,4‐dimethyl‐5{[(trifluoro‐methyl)sulphonyl]amino} phenyl) acetamide]] was applied early (mid‐May) or late (late May) at low rate [daminozide, 4 kg active ingredient (a.i.) ha−1; or mefluidide, 0·13 kg a.i. ha−1] or twice the low rate (high rate) to an early‐flowering cultivar, Florex, and a late‐flowering cultivar, Altaswede; the controls were the untreated cultivars. Red clover was deficient in S, but all other minerals were present in sufficient amounts for productive cattle. The first cutting showed increases in P and Zn contents after an early application of daminozide, Cu was increased when the high rate of daminozide was applied early, and Ca, Cu, K and Mg were increased when mefluidide was applied early or at the high rate. There were no interactions between daminozide and cultivar in terms of minerals, but mefluidide treatment increased Mg in Altaswede only. Altaswede showed a narrower N/S ratio in the first cutting, and contained more P, K and Mg in both cuttings than did Florex. This study indicated that growth regulator application, particularly the early application of daininozide at the high rate, improved the mineral profile in red clover.