bluuebunny/crossref_metadata_2025 huggingface dataset:
THE SEASONAL PATTERN OF DRY‐MATTER PRODUCTION OF GRASSES IN THE NORTH PENNINES
Authors: Morris R. M. , Thomas J. G.
Published: April 2006

The seasonal pattern of DM prodaction of Lolium perenne, Cynosurus cristatus. Anthoxanthum odoratum. Festuca ovina and Agrostis stolonifera. cnt to 3 cm at 6‐week intervals was studied on five sites, ranging from 49 to 303 m above sea level, in north‐west Lancashire. Total annual production declined from a mean of 704 g/m2 on the lowest site, to 553 g/m2 on the highest, largely as a result of a severe depression in the spring peak of production, i.e. from 6.7 to 2.5 g/m2 per day. Later in the year, the daily rate of DM production was similar on all sites. Species varied in their response to increased altitude; Lolium was worst affected by this and Festuca least. The significance of these results, and possible reasons for the decline in spring production are discussed.
A NOTE ON THE SUITABILITY OF THE IN VITRO DIGESTIBILITY TECHNIQUE FOR VERY SMALL PLANT SAMPLES
Authors: McLeod M. N.
Published: April 2006

The two‐stage in vitro digestibility technique was scaled down to use 0.1 g samples. The accuracy of predicting in vivo DM digestibility by the use of micro‐samples was studied, using 35 samples of four grass species of known in vivo digestibility. When the sample size was reduced from the normal 0.5 g to 0.1 g, the residual standard deviation of the regression relating in vitro to in vivo DM digestibility was increased from ±2.5 to ±3.4 digestibility units. Grinding the samples more finely than through a 1.0 mm screen did not improve the accuracy of predicting in vivo digestibility.

It was concluded that the in vitro method may be used with micro‐samples where necessary, but with less accuracy than the macro‐technique. For maximum accuracy, the use of standards of known in vivo digestibility is necessary.
A TECHNIQUE FOR THE STUDY OF ‘FOULING’ BY GRAZING CATTLE
Authors: Smith A. , Boswell C. C.
Published: April 2006

The need to isolate defoliation from other influences arising from grazing cattle nsed in experiments has led to the development of a cage which allows cattle to graze, hut protects the sward from treading and the deposition of faeces and nrine. The technique is descrihed and a description given of experimental work on the harvesting of swards in the presence or absence of these other influences.
SEASONAL PATTERNS OF DIGESTIBLE ORGANIC MATTER AND PROTEIN PRODUCTION FROM GRASSES IN THE NORTH PENNINES
Authors: Thomas J. G. , Morris R. M.
Published: April 2006

The seasonal pattern of digestible organic matter (DOM) and crude‐protein production of Lolium perenne, Cynosurus cristatus, Anthoxanthum odoratum, Festuca ovina and Agrostis stolonifera cut to 3 cm at 6‐week intervals was studied at five sites ranging from 49 to 303 m above sea level in north‐west Lancashire for the years 1969–70.

DOM production declined from 482 g/m2 on the lowest site to 220 g/m2 on the highest; similarly protein production declined from 142 g/m2 to 73 g/m2. Small but significant differences in the percentage of crude protein occurred only ia 1970, whereas DOM as a percentage of DM in the various species differed considerably between sites in both years. The significance of the results and the seasonal fluctuations in production are discussed.
POTENTIAL PASTURE PRODUCTION IN THE UPLANDS OF WALES
Authors: Munro J. M. M.
Published: April 2006

A comprehensive study of the climatic, soil and vegetation restraints on grassland production in the hill areas of Britain is an essential preliminary stage in land use planning for those areas. Climatic data, recorded continuously at four centres in mid‐Wales, emphasize the extent of altitudinal, topographic, seasonal and diurnal variation in zones with improvement potential. Annual solar energy income is negatively correlated with rainfall and cloud cover. Under wet conditions in the western hills, mean daily solar radiation during 1966–69 decreased by 15% between two centres at 30 and 305 m (103 and 1100 ft) 0.D. from 9.92 MJ/m2 to 7–07 MJ/m2= (204 to 169 cal/cm2). Radiation receipts in the drier eastern uplands at 305 m (1000 ft) were as high between May and August as in the western lowlands, but winter temperatures were considerably lower. Comparisons are made with conditions in other upland areas of Britain.
USES AND CAPABILITIES OF ELECTRONIC CAPACITANCE INSTRUMENTS FOR ESTIMATING STANDING HERBAGE
Authors: Neal D. L. , Neal J. L.
Published: April 2006

A meter using electronic capacitance to estimate weight of standing vegetation was first tested in 1949. It proved to be faster and more accurate than most indirect methods of measurement. Since then, other similar instruments have been built and several problems have become apparent. Short or dry vegetation, non‐homogeneous distribution of vegetation, non‐homogeneous phenology, and electronic circuit instability were the major problems. The chief steps in the development of capacitance instruments for estimating vegetation weight are discussed. The significance of each of the major problems has been greatly reduced by improvements in instrumentation. The technique of using electronic capacitance has now proved itself useful under a wide variety of range conditions.
CLASSIFICATION OF STARCH‐ AND FRUCTOSAN‐ACCUMULATING GRASSES AS C‐3 OR C‐4 SPECIES BY CARBON ISOTOPE ANALYSIS
Authors: Bender Margaret M. , Smith Dale
Published: April 2006

Type of nonstructural polysaccharide, starch or fmctosan, accumulated in the lower intemodes of grass shoots was not completely consistent with carbon isotope determinations and does not appear to he dependent on the type of photo‐synthetic pathway that prevails.
A NOTE ON THE EVALUATION OF THE NUTRITIVE VALUE OF FORAGE CROPS BY THE ACETYL BROMIDE TECHNIQUE
Authors: Morrison I. M.
Published: April 2006

It has been shown in the past that in vitro digestibility of forage crops could be accurately predicted by the acetyl bromide absorption technique. This note demonstrates that in vivo digestibility values can be accurately predicted by this method and that in this respect the method is comparable in accuracy with the in vitro digestibility technique.
POTENTIAL PASTURE PRODUCTION IN THE UPLANDS OF WALES
Authors: Munro J. M. M. , Davies D. A.
Published: April 2006

Study of the growth of heavily fertilized swards of S23 perennial ryegrass (Lolium perenne) at a hill and a lowland centre in mid‐Wales during 1968–69 demonstrated that lower productivity in the uplands could only be partially attributed to a shorter growing season and poorer summer growth conditions. Comparison of yields with potential transpiration estimates indicated that winter damage had an important bearing on production during the following year. In 1969, the adverse combination of a mild autumn and a severe winter led to a spring tiller density which was less than 25% of normal at the hill centre. With an annual fertilizer input of over 500 kg N/ha (480 lb N/ac) total DM production in 1968 and 1969 was 10.6 and 4.4 t/ha at the upland site compared with 14.8 and 10.1 t/ha in the lowlands (9450, 3920, 13,190 and 9000 lb/ac).
A LOW‐COST SYSTEM FOR GRAZING SMALL EXPERIMENTAL PLOTS
Authors: Batten G. D.
Published: April 2006

A technique using a lead running on a suspended wire, is described which allows small plots, e.g. 0.01 ha (1/40 ac) or less, to he grazed individually at 30% of the cost of conventional fencing. It also offers a means of minimizing the concentration of nutrients in dung on camp areas.
COMPETITION FOR PHOSPHATE BETWEEN A DIPLOID AND A TETRAPLOID PERENNIAL RYEGRASS
Authors: Harries J. H. , Norrington‐Davies J. , Howse K. R.
Published: April 2006

The relative uptake of P was measured in two varieties of Lolium perenne using radioactive tracer techniques. The diploid cv. Hora and the tetraploid cv. Terhoy were sown as pure stands and as 50:50 mixtures at both high and low density. Uptake from four depths 10, 20, 30 and 40 cm was examined. The results showed that: in pure stands the diploid uptake at 10 cm exceeded that of the tetraploid although at deeper levels the uptake pattern was similar; in mixtures the uptake of the tetraploid variety increased markedly at 10 cm while that of the diploid variety decreased. The diploid compensated for its decreased uptake at 10 cm by a substantial increase in uptake at 20 cm; overall the tetraploid variety had a deeper pattern of uptake than the diploid; in general, uptake at high density was greater than that at low density; the mixture showed a greater degree of P utilization than pure stands in the upper layers of the soil; when these two varieties are grown together in 50:50 mixtures the tetraploid is relatively more efficient in taking up.
RED CLOVER SILAGE FOR MILK PRODUCTION
Authors: Castle M. E. , Watson J. N.
Published: April 2006

Nine wilted silages made from tetraploid red clover were fed in four winter‐feeding experiments to 32 Ayrshire cows. The DM content of the silages averaged 23±5% (range 15±8–27±1) and contained an average of 19±6% crude protein, 14±2% digestible crude protein and 52±0% digestible organic matter. The pH values varied from 4±0–6±2, depending on the DM content and mechanical treatment of the crop, and the rate of application of formic add. The silages were fed ad lib.with supplementary concentrates and the average daily intakes of silage DM ranged from 16±0–24±0 Ib/cow (7±3–10±9 kg). The highest daily intakes were obtained with double‐chopped silage containing 24–26% DM with a pH of 4±0. Although the red‐clover silage had a high content of N and apparently provided a balanced ration with the addition of barley, yields of milk were increased significantly by substituting 1 Ib (0±4 kg) groundnut cake for 1 Ib barley in the daily ration of the cow. The silage contained oestrogenic compounds but the breeding pattern and fertility of the cows were not affected adversely. The tetraploid red clover produced approximately 9000 Ib DM/ac (10 100 kg/ha) in the 1st‐harvest year and it is concluded that a safe and highly palatable silage with high intake characteristics can be made if the clover is wilted to about 24% DM, double chopped, and formic acid is applied at the rate of 0±5 gal/ton.
THE DRY‐MATTER PRODUCTION, BOTANICAL COMPOSITION, IN VITRO DIGESTIBILITY AND PROTEIN PERCENTAGE OF PASTURE LAYERS
Authors: Clark Jennifer , Kat C. , Santhirasegaram K.
Published: April 2006

ABSTACT

Irrigated plots of a mixed sward of four grasses and white clover were cut to a height of 3 cm in either June, August, October, December or February. The plots cut at each commencement date were harvested when the height of growth of the pasture was either 10, 18, 25, 32, 40, 48 or 55 cm. At each harvest, the pasture was cut at 7 to 8 cm intervals down to a height of 3 cm. DM production, botanical composition, in vitro digestibility (DOM) and CP of each layer was determined.

DM production declined from the lower to the upper layers for pastures shorter than 32 cm. For pastures taller than 32 cm, DM production declined from the lower to the middle layers, then increased in the upper layers, due mainly to the presence of seed heads.

Maximum percentages of DOM and CP were observed for the middle layers of the pastures taller than 25 cm. For pastures shorter than 25 cm, DOM and CP percentages increased from the lower to the upper layers, for all commencement dates. The percentages of DOM and CP of each layer decreased as the height of growth increased.

The percentage of DOM showed a positive correlation with the percentages of Lolium perenne, Bromus unioloides and Trifolium repens, and a negative correlation with the percentages of Paspalum dilatatum and chlorotic material. The percentage of CP showed a positive correlation with the percentages of Paspalum dilatatum, Dactylis glomerata and Trifolium repens and a negative correlation with the percentages of chlorotic material and the total of the four grasses within the pasture layers.

The lower layers of the pasture produced large quantities of DM and, despite the lower in vitro digestibility of these layers, they produced more DOM than the other pasture layers. The DOM production of the pasture increased with increasing height of growth, but decreased as the commencement date was altered from winter through to the end of summer.
EFFECTS OF DIFFERENT GRAZING ROTATIONS ON PASTURE PRODUCTION
Authors: Tainton N. M.
Published: April 2006

Different grazing treatments applied to pastures in which perennial ryegrass was dominant had little influence on DM production during the main reproductive growth period in late spring and early summer. Lax and infrequent grazing at this time did, however, reduce tiller density. During the dry summer period lax infrequent grazing increased production by 20%, while in the vegetative growth period in autumn those pastures which were alternately lax‐ and hard‐grazed outyielded those which were hard grazed by 63%.

In all treatments, initial recovery growth resulted almost exclusively from the production of leaf tissue. The rate of leaf growth declined three to five weeks after grazing, depending on treatment and season, and subsequent yield increase was dominated by sheath and stem growth.
LAND RESTORATION WITH PULVERIZED FUEL ASH
Authors: Gillham E. W. F. , Simpson D. T.
Published: April 2006

Experiments were carried out with different depths of added topsoil, with different methods of cultivation and with different rates of application of fertilizers on an ash disposal site near Newark. Good yields of hay and wheat were obtained and were shown to vary systematically with the treatment of the plots. Good yields of wheat were obtained with a top dressing of 125 kg N/ha even on bare ash but, in contrast with the yields of DM from grass, yields of grain tended to increase with increasing depth of added soil. This pattern appeared to be influenced by the variations in spring rainfall. There appeared to be no adverse effects of uptake of trace elements from the ash.
STUDIES IN RESPONSE TO NITROGEN
Authors: Hunt I. V.
Published: April 2006

Data are presented demonstrating the effects of applying fertilizer N at 59, 118 or 177 kg/ha on 16 Apr. on uptake of K, P. Ca, Mg and Na in primary growth (PG) harvested 8, 12, 16, 23, 29, 45 and 57 days afterwards, and residual effects in two successive regrowths (RG1 and RG2) harvested on 12 June and 13 Aug., respectively.

Significant residual responses as uptake of K, P, Ca, Mg and Na were shown in RG1 and RG2 after all dates of harvesting PG. The residual responses compensated for poor uptake in PG. Thus, low uptakes to the second increment of N were followed by high residual responses in both regrowths; and low uptakes in PG harvested shortly after applying the fertilizer N were followed by high residual responses.

Averaged over the seven dates of PG harvest, the sum of responses (PG+RG1+RG2) to the second N increment was greater than total response to the first increment in P and Mg, considerably greater in Ca and Na and slightly lower in K. These marked residual responses to the second N increment were most noticeable where PG was harvested 23 days after applying fertilizer N and became less marked as date of PG harvest was advanced.

Percentage K, P, Ca, Mg and Na in DM of the PG and of RG1 increased as N application was raised. By RG2, the residual effects of fertilizer N on percentage K. P and Mg were reversed to give reduced percentages with increased N application to PG. indicative of deficiencies in availability of these elements.

The application of 177 kg N/ha to PG resulted in the release of additional soil N and of other mineral elements which could lead to their depletion.
THE LEGUME—A REAPPRAISAL OF ITS PLACE IN TODAY'S FARMING*
Authors: Aldrich D. T. A.
Published: April 2006

The last 10 years have seen a marked shift in Britain from the growing of legumes towards the use of fertilizer N. Many farmers are now reassessing the position Decause of increasing fertilizer prices and because of improvements in clovers and lucerne through plant breeding.

On the intensive dairy farm legumes can play an important part in the conseravation block. The yield of lucerne without applied N is as high as from ryegrass with 250 units N/ac. Red clover is also useful over a wide range of soil types.

On the less intensive farm, white clover should be contributing throughout the grazing area. there are many reasons for poor white clover populations in pastures; one of these is the fungus disease Sclerotinia trifoliorum, commonly known as clover rot. Varieties resistant to this disease are available in both red and white‐clover. Verticillium wilt in lucerne bas also been checked by the plant breeder.

Improved legume varieties justify a completely new look at these crops and the possibilities for lucerne in this country appear to be particularly good.
THE EFFECT OF AUTUMN MANAGEMENT ON WINTER DAMAGE AND SUBSEQUENT SPRING PRODUCTION OF SIX VARIETIES OF LOLIUM PERENNE GROWN AT CAMBRIDGE
Authors: Thomson A. J.
Published: April 2006

Six perennial ryegrass varieties which were known to differ in winter hardiness were subjected to ten managements comprising two N rates and fire autumn cutting treatments. Autumn yields and soluble carbohydrate contents were measured, also the amount of winter damage in February and subsequent spring yields.

The winter was mild, herbage damage was slight and no plant deaths were recorded, but significant differences were found between cutting treatments and varieties. The amount of winter damage increased with the length of the autumn rest period and with the degree of winter dormancy of individual varieties, indicating that natural senescence was a more important causative agent than frost action. Spring yields were affected by the amount of winter damage but there were considerable interactions between varieties and environments.

The results are discussed in relation to autumn management practices, choice of variety for different locations and measurements of winter hardiness. The induction of winter dormancy by day length or low temperature reactions is considered in the breeding of varieties for maximum production in different parts of the country.
A TEMPERATURE INDICATOR FOR USE DURING OVEN‐DRYING OF HERBAGE
Authors: Wolf D. D.
Published: April 2006

The drying of small herbage samples should be as rapid as possible so as to limit respiratory loss and enzymatic interconversions, especially if certain nonstnictnral carbohydrates are to be assayed. An inexpensive thermo‐switch is described that indicates the time required to heat a mass of tissue in an oven to a given temperature. The time required to heat green herbage to a temperature (55°C) that will inactivate respiratory enzymes can be determined.
THE RESPONSE OF S24 PERENNIAL RYEGRASS SWARDS TO IRRIGATION
Authors: Garwood E. A. , Tyson K. C.
Published: April 2006

Variations in soil‐water and plant‐water status were examined in swards of perennial ryegrass over a period of 2 years. Unirrigatcd swards were compared with swards partially irrigated after cutting and with swards fully irrigated after cutting and then again whenever a 25 mm potential soil water deficit (SWD) arose. Two levels of N were applied to the swards (Nj= 250 kg N/ha, NT= 500 kg N/ha in each year). Frequent measurement of the water in the soil profiles beneath these swards with a neutron soil‐moisture probe, enabled comparisons to be made of the actual SWD with the potential SWD on which the irrigation regimes were based. In the unirrigated swards the actual rate of water use by the swards fell below the potential rate of use at a potential SWD of approximately 50 mm. On the other hand, frequent irrigation at a potential SWD of 25 mm often failed to maintain the actual deficit within 25 mm of field capacity. Under both the unirrigated and the partially irrigated swards, greater use was made of the soil water below 30 cm depth in the N2 treatment than in the N1.

The pressure‐chamber technique proved particu larly suitable for measuring the variation in leaf‐water potential (LWP) of grasses in the field. LWP was highest (least negative) at dawn and, provided that no dew was present on the leaves, was related to the actual SWD. There was no direct relationship between the daily minimum value of LWP and SWD, the former being determined largely by evaporative demand. However, LWP in frequently irrigated swards rarely fell below –15 atm, whereas much lower values were recorded in swards on drier soils. It is suggested that the effect of irrigation on plant‐water stress may be most readily assessed from the LWP at dawn.
THE VOLUNTARY INTAKE AND DIGESTIBILITY BY SHEEP OE LEAF AND STEM FRACTIONS OF LOLIUM PERENNE
Authors: Laredo M. A. , Minson D. J.
Published: April 2006

The leaves of tropical grasses are eaten in larger quantities than stems of similar DM digestibility. To determine whether the same fact applied to a temperate grass, studies were made with leaf and stem fractions of Lolium perenne. The leaves of L. perenne had a 20% higher voluntary intake than the stems, white the DM digestibilities were only slightly higher (67·3%ν. 64·8%). The leaves also had a larger surface area/g, a higher initial (12 h) fermentation rate in vitro, larger content of pepsin‐soluble DM, and a smaller energy require ment to grind I g DM in a laboratory mill compared with the stems.

The difference in voluntary intake between the leaves and stems of L. perenne was smaller than that for a number of tropical grasses.
REACTION OF ITALIAN RYEGRASS CULTIVARS UNDER GRAZING AS COMPARED WITH CUTTING
Authors: Camlin M. S. , Stewart R. H.
Published: April 2006

Ten cultivars of Italian ryegrass (Loliumultiflorum) were assessed over two seasons under a cutting regime and a cattle grazing system. A high correlation between the two managements was obtained in respect of annual production, the ranking order of yield being similar in each case for the range of cultivars. Persistence under grazing was highly correlated to that under cutting when assessed at the end of the experiment. There was, however, some evidence of interaction between the two systems in the performanee of one cultivar. The results are discussed in the context of herbage cultivar evaluation for the purpose of recommending those most suitable for general use.
FACTORS LIMITING ANIMAL PRODUCTION FROM GRAZED PASTURE*
Authors: Greenhalgh J. F. D.
Published: April 2006

Animal production from intensively managed pasture (240 units N/ac or 300 kg N/ha applied annually) should in theory reach 11,000 Ib/ac (12,500 kg/ha) of milk or 1550 lb/ac (1750 kg/ha) of liveweight gain per year. The figure for theoretical milk production is achieved in experiments, although rarely approached in commercial practice; the figure for liveweight gain is never approached, either experimentally or commercially. On commereial farms in Britain, the average stocking rate for grazed lowland pasture in 1971 was about 0·74 cow equivalents/ac (l±82/ha), compared with a theoretical target of 1·9/ac; in 1969 fertilizer N application was about 48 units/ae (60 kg/ha). The main purpose of this paper is to suggest reasons for the differences between practical, experimental and theoretical levels of production.

Economic factors may deter farmers from intensifying their grassland management, but the deterrent to high stocking rates may be the fear of running out of grass. In practice, ungrazed herbage is used as a buffer, but other feeds might be used for this purpose. Concentrates, pelleted roughages and even long dried grass and silage are too attractive to grazing beef cattle to be offered to appetite; but silage might be used as a long‐term buffer. Fouling of pasture reduces efficiency of harvesting, but attempts to overcome this effect, by conditioning of grazing animals, spreading excreta or by alternation of grazing and cutting, have largely been unsuccessful.

High production per unit area cannot be achieved without high production per animal. Legumes have often been found to increase production per animal, and a technique has been developed for growing red‐clover and grass in adjoining areas and grazing them together. The clover was grazed satisfactorily by dairy cows (and caused no bloat) but failed to increase milk yield per animal.

Recent calorimetric studies of grass have shown that the net energy value of digestible organic matter is variable, and in particular is low for late‐season herbage.
A COMPARISON OF TWO HAYS FOR BEEF PRODUCTION
Authors: Forbes T. J. , Renton A. R.
Published: April 2006

A medium quality barn‐dried hay and a poor quality field‐cured hay were each supplemented with 3 levels of concentrate in the diet of young beef cattle, averaging 313 kg liveweight. The supplement was given on predetermined hay concentrate metabolizable energy (ME) ratios based on the determined ME of the hays and an assumed ME of 3·0 McalsAg DM for the supplement. The hay concentrate ratios used were 1:1, 1:2 and 1:3, the aim being to provide a reasonable rate of growth (0·7 kg/day) with the poorer hay. It was necessary to include urea in the concentrate mixtures used on the 1:1 and 1:2 ratios with the field‐cured hay. The urea appeared to have an adverse effect on the intake and utilization of DM on the 1:1 ratio. The range of mean intakes of supplement DM was 3·02 to 4·41 kg/day for the barn‐dried hay and 2·23 to 4·61 for the field‐cured hay. Mean daily liveweight gains with the barn‐dried hay were 0·76, 0·89 and 0·85 kg for the 1:1, 1:2 and 1:3 ratios, respectively, with no significant difference between ratios. The mean daily gains with the field‐cured hay were 0·39, 0·77 and 0·75 for the three ratios, the mean gain on the 1:1 ratio being significantly lower than those of the other ratios. The ME conversion ratios were not significantly affected by either ratios or hay type, except on the 1:1 ratio with field‐cured hay. There were significant differences between the barn‐dried hay and field‐cured hay diets in the digestibilities of DM, organic matter, crude protein and energy; the mean coefficients for DM being 74·5% and 65·6%, respectively.
A NOTE ON URINE SCORCH CAUSED BY GRACING ANIMALS
Authors: Richards I. R. , Wolton K. M.
Published: April 2006

Observations were made on urine scorch on pastures at North Wyke. Scorch was caused by cattle and by sheep and occurred sporadically throughout the grazing season in wet and in dry weather, but not all urinations caused scorch. Where ryegrass was completely killed, subsequent colonization was by weed speeies. A relationship was found between extent of scorch and grass N content and the scorching effect appeared to be on the root system of the grass and not on the foliage.
THE EFFECT OF THE TIME AND LEVEL OF INJECTION OF ANHYDROUS AMMONIA ON THE PRODUCTIVITY OF GRASSLAND
Authors: Walpole P. R. , Hutton K.
Published: April 2006

Four levels of nitrogen, 188, 285, 358 and 392 kgJ.ha (150, 225, 285 and 350 units/ac) supplied as anhydrous ammonia were injected on each of four occasions, 18 Dec, 5 Feb., 12 Mar. and 16 Apr. DM and CP yields were estimated at each of three harvests taken on 4 June, 19 July and 28 Sept

Total DM yields showed only a 10% difference between the highest yielding injection date, 12 Mar., which yielded 12270 kg/ha (10946 Ib/ac) and the lowest, 16 Apr., which yielded 11169 kgJ.ha (9963 Ib/ac). Early injection of ammonia promoted growth during the late spring and later injections resulted in increased yields at the two later harvests. The responses per kg fertilizer N were 11.9 kg DM (10.8 lb/unit) and 3.6 kg CP (3–3 Ib/unit). It was concluded that ammonia should be applied to grassland before April and, preferably, during March, for maximum yields of DM and CP.
SILAGE AND MILK PRODUCTION. A COMPARISON BETWEEN BARLEY AND DRIED GRASS AS SUPPLEMENTS TO SILAGE OF HIGH DIGESTIBILITY
Authors: Castle M. E. , Watson J. N.
Published: April 2006

Grass silage made in late May from S23 perennial ryegrass was offered to 14 Ayrshire cows in a 16–week winter‐feeding experiment. The silage had a DM content of 23.2% and contained 16–8% CP and 70.4% digestible organic matter in the DM. The silage was fed ad lib. as the sole feed in the control treatment, and supplemented with either barley or higuality dried grass cubes at the rate of 2, 3 and 4 kg/10 kg milk (2, 3 and 4 Ib/gal) in the other 6 treatments. The daily intake of silage DM was 11.6 kg/cow (25.6 lb) in the control, and significantly less in the supplement treatments. Silage intakes were higher in the dried grass than in the barley treatments. The mean daily yields of milk were 14.5 kg.cow (32.0 lb) in the control, 15.7, 16.6 and 17.0 kg (34.6.36.6 and 37.5 lb) in the barley treatments, and 17.8, 20.2 and 19.8 kg (39.2, 44.5 and 43.6 lb) in the drierass treatments, at the 2, 3 and 4 kg rates of feeding, respectively. The solidoat (SNF) content of the milk was lowest in the control treatment and highest in the drierass treatments. It is concluded that grass silage of high digestibility could be made successfully on a farm scale and that, with such a silage, a supplement of higuality dried grass was superior to a supplement of barley for milk production.
THE EFFECT OF INTRAVENOUS INFUSIONS OF METHIONINE ON THE VOLUNTARY INTAKE OF GRASS SILAGE BY SHEEP
Authors: Kelly N. C. , Thomas P. C.
Published: April 2006

The effect of intravenous supplements of L‐methionine on the voluntary intake of a ryegrass silage, prepared using formic acid as an additive, was determined in a 4×4 Latin Square experiment with 4 sheep. Animals receiving no methionine consumed 1061 g DM/day; those receiving 0.8, 1.2 and 2.0 g methionine/day consumed 1015, 1012 and 1078 g DM/day. The concentration of methionine in blood plasma (Y; (imoles/I) increased with the dose rate of methionine infused (X; g/day) such that Y=36.7 + 38.3X (r=0.80; P<0.001). It is concluded that with a diet of this type methionine may be limiting for protein synthesis in the tissues but is not involved in the control of food intake.
NITROGEN AND ITALIAN RYEGRASS
Authors: Wilman D.
Published: April 2006

In an experiment, described earlier (19) to study the regrowth of Italian ryegrass following a cut in late April, the N and nitrate‐N content of herbage at 3 levels of applied N followed a similar pattern to that noted in earlier years in Cambridge. N content, however, did not fall to such a low level as in Cambridge. N yield fell later and less quickly than in Cambridge. The application of a very high level of N, 175 lb/ac (196 kg/ha), raised N and nitrate‐N content and yield from the second or third week onwards. Changes with time in P and K content and yield were broadly similar to those for N. Level of N had only a small effect on content of P and K. Following the period of increase in yield of N, P and K, there was a period of about 6 weeks of relatively constant yield, followed by a fall. The content of N, P and K in fresh, rather than dry, herbage changed little with time from the fourth to the fourteenth week, despite major changes in crop maturity. The ratio P: K was little affected by level of N or time of harvest.
SWARD PRODUCTIVITY WITHIN MICRO‐PATTERNS OF HEIGHT AND FREQUENCY OF DEFOLIATION
Authors: Smith A. , Macauley J. R.
Published: April 2006

An experiment is described in which 10 cutting treatments were applied to plots of perennial ryegrass. In 4 treatments the swards were cut uniformly using one of the following regimes: cut to 15 cm every 2 weeks (regime hf); cut to 15 cm every 6 weeks (hi); cut to 5 cm every 2 weeks (If); cut to 5 cm every 6 weeks (li). In the remaining 6 treatments, each plot was cut in alternate 9 cm strips using combinations of two of the above regimes; hf/hi, hf/lf, hf/li, hi/If, hi/li, and If/li. The non‐uniform cutting in the latter 6 treatments resulted in a micro‐pattern of height and/or frequency of defoliation.

DM yield from the best non‐uniform cutting method (If/li) was as great as that from the best uniform method (li). This was due to an increased yield from areas under regime If when adjacent to areas under li, compared with uniform defoliation under regime If. Results for other treatments also showed that the yield from an area can be influenced by the defoliation regime applied to adjacent areas. The trend was for yield to be greatest if adjacent areas were cut high (as opposed to low) or frequently (as opposed to infrequently). There was less bare ground and more perennial ryegrass and weeds at the end of the experiment in areas previously adjacent to frequent (0 as opposed to infrequent (i) cutting regimes.

To assist in the interpretation of field results, an experiment was carried out in which uniform and non‐uniform cutting treatments were applied to individual plants of perennial ryegrass growing in pots of soil in a glasshouse. There was some evidence of an interaction between the growth of high and low parts of plants cut non‐uniformly. There is a discussion of the possibility of devising new ways of harvesting grass by cutting. It is suggested that the non‐uniform grazing pattern of livestock may not be wasteful.
The use of a fluorescent pigment to record the distribution by cattle of traces of faeces from dung pats
Authors: BOSWELL C. C. , SMITH A.
Published: April 2006

The extent of post‐defaecation redistribution of faeces by cattle in a grazed pasture was determined by adding to dung pats a pigment which is fluorescent in ultra‐violet light. Traces of faeces which would normally not be detected were located under ultra‐violet irradiation at night. More traces were redistributed from dung pats situated in areas where stock congregated than from dung pats in other areas of paddocks. Most traces occurred at distances of up to 2 m from each indicator dung pat treated with the pigment. The area of sward affected by faeces was over 100 times the area of individual dung pats. It is suggested that the distribution of infective parasitic larvae will follow the distribution of the traces rather than simply that of the dung pats. Grazing behaviour may also be affected by contamination of herbage by traces of faeces.
Harvest ripeness in grass seed crops
Authors: PEGLER R. A. D.
Published: April 2006

Ten varieties of forage grasses, including perennial and Italian ryegrasses, tall and meadow fescues, cocksfoot and timothy, grown in seed‐production drills were sequentially harvested from 14 days after peaks of flowering. Seed germination capacities were generally good in seed samples harvested early in the mattiration period, with the exception of timothy. PeaJc yields of germinable seed were usually obtained some time after shedding had begun; delay in harvesting resulted in further seed losses, some of which were substantial. The maxima of individual seed weights mostly did not coincide with, and were frequently later than the peaks of germinable seed yields. Endospenns did not generally harden until after the maxima of germinable seed yields. Endosperm development stages were found to be reliable guides to assessment of correct harvest date, and it is suggested that examination of endosperm consistencies be used to corroborate assessment of harvesting times tising moisture meters.
The effect of physical form of a silage on its voluntary consumption and digestibility by sheep
Authors: THOMAS P. C. , KELLY N. C. , WAIT M. K.
Published: April 2006

Six castrated male sheep were used in a two‐period crossover experiment to investigate the effect of mincing on the voluntary intake and digestibility of a silage. The silage was a high‐quality material, containing 68 % digestihle organic matter in the dry matter, prepared from S24 perennial ryegrass cut with a precision chop forage harvester and ensiled with the addition of 2.3 1 t−1 formic acid as preser vative. The median size of particles in the unprocessed silage was 10–20 mm and in the minced silage 2–3 mm.

The intakes of dry matter, organic matter and nitrogen for the minced silage were greater than for the unminced material, and for dry matter and organic matter intakes the differences were signi ficant (P<0.01). Mincing was associated, however, with a depression in the digestibility of all three constituents which offset the increase in intake. The intakes of digestible organic matter were 817 g d‐1 for the minced silage and 729 g d−1 for the unminced material (P>0.05). Corresponding figures for digestible nitrogen intakes were 208 gd−1and23.0 gd−1 (P>005).

It is concluded that with high‐quality silage diets there is a physical component in the mechanism for the control of voluntary food intake. It is suggested that for sheep, depressions in the digestibility of dietary constituents are unlikely to occur until silages are chopped to a median particle size of 5–10 mm.
The acetylene reduction assay as a means of studying nitrogen fixation in white clover under sward and laboratory conditions
Authors: HALLIDAY J. , PATE J. S.
Published: April 2006

The acetylene reduction assay was used to follow seasonal changes in nitrogen fixation activity in a white clover‐perennial ryegrass ley in Northern Ireland. The annual estimate for fixation by the ley was 268 kg ha−1 (239 lb/acre) nitrogen virtually all of which was fixed during March to October. Nitrogen fixation was curtailed drastically after the ley was cut but recovered as new foliage expanded on the clover. Glasshouse experiments described the effects of temperature, shading and defoliation on nitrogen fixation by white clover, and indicated that these factors might be important in modifying symbiosis under field conditions.
Effect of rotary‐drum‐drier exit temperature and length of pre‐drying storage time on digestibility of dried grass cobs
Authors: MARSH R.
Published: April 2006

The effect of exit temperature of a rotary‐drum‐drier and of the length of pre‐drying storage time on chemical composition and digestibility of dried grass cobs was investigated in two experiments. Increasing exit temperature from 77 to 166°C reduced WSC, NFE and available lysine content and increased CF content of dried grass. In vitro and in vivo DM digestibility was reduced by 16.4 and 24.5 percentage units respectively. Increasing length of pre‐drying storage time also reduced WSC and available lysine content and reduced in vitro and in vivo DM digestibility by 2.4 and 5.1 percentage units respectively. The greatest reduction in in vivo digestibility in both experiments occurred in the CP fraction.
Seedling growth of four grasses
Authors: HAYES P.
Published: April 2006

Investigations were conducted into the seed reserves, shoot and seminal root growth of Lolium perenne, Festuca arundinacea, Holcus lanatus and Poa trivialis. Data are presented for the caryopsis, palea and lemma weights of these species. Shoot lengths of Lolium and Festuca were very similar but seminal root lengths of Lolium were longer and emerged earlier than those of Festuca. The caryopsis in Lolium lost weight much more rapidly in germination than Festuca. Seedlings of Lolium and Festuca showed similar increases in shoot length but Lolium had more rapid rates of seminal root growth and weight loss from the caryopsis. It is suggested that poor field establishment of Festuca may be due to poor mobilization of seed reserves and consequential poor seminal root growth. The possibility of selecting for good seminal root development in Festuca to improve establishment is suggested.
Pathogens occurring on ten varieties of ryegrass at Rothamsted in 1973–74
Authors: PLUMB R. T. , JENKYN J. F. , BOWEN ROBERTA
Published: April 2006

Six varieties oi Loliumperenne, three of L. multiflorum and one hybrid (L. multiflorum × L. perenne) were assessed for diseases over two harvest years. Crown rust (Puccinia coronata) and mildew (Erysiphe graminis) occurred on some varieties in 1973. Leaf spotting (Drechslera spp.) was common, but slight on most varieties, in both years. Ryegrass mosaic virus (RMV) and its mite vector, Abacarus hystrix were present on all varieties in the second year. The relative susceptibility of varieties to RMV was similar in the field and in glasshouse tests.
Leaf protein production and use on the farm: an economic study
Authors: DUMONT A. G. , BOYCE D. S.
Published: April 2006

A linear programming model to provide information on the economic feasibility of on‐farm production and use of leaf protein from grass is described. The unwilted grass is mechanically separated into a protein‐rich ctird, which is fed to pigs or other non‐ruminants, and a high‐dry matter, fibrous residue which is ensiled and fed to ruminants.

In the model, the gross margin from a livestock farm which uses a conventional silage system for a dairy herd is compared with that from the same farm using forage fractionation. The difference in gross margins is available to pay for the additional cost of the fractionation equipment and to provide additional profit.

The model considers the machinery performance, costs and labour constraints within which the new system would have to operate if it were to be economic. Results indicate that under a wide range of farm sizes and situations, forage fractionation shows an economic advantage over present forage conservation methods if machinery of the required throughput and cost were to be developed for on‐farm use.
Factors influencing the proportion of natural hybrids between Lolium perenne L. and Festuca pratensis Huds. in permanent pastures
Authors: GYMER P. T. , WHITTINGTON W. J.
Published: April 2006

Hybrids between ryegrass and meadow fescue form rarely but occur widely in old pastures. In one experiment six different hybrid genotypes were able to compete, on equal terms, with members of their parental species. In two others the proportion of the total yield due to one hybrid genotype was increased by added fertilizer or by reduced water supply.
The physiological response to cutting in Italian ryegrass
Authors: CLARK BRENDA J. , PRIOUL J.‐L. , COUDERC H.
Published: April 2006

The kinetics of decline in net photosynthesis and transpiration after cutting was followed in a batch of Lolium multiflorum leaves at light saturation in an assimilation chamber where air temperature, leaf temperature, carbon dioxide concentration and water vapour concentration were controlled. After leaf excision the rates of photosynthesis and transpiration increased or remained the same for 1–2 min and then decreased sharply following a curve with two breaks of slope at 15 min and 30 min. To investigate stomatal behaviour, fragments of leaf tissue were removed, fixed by freezing in liquid nitrogen, then examined by scanning electron microscopy. The stomata were optically closed by 15 min after excision. The practical implications for field drying of Italian ryegrass are discussed.
Comparisons of some factors affecting digestibility in sheep and cows
Authors: THOMAS S. , CAMPLING R. C.
Published: April 2006

A comparison was made of some factors affecting digestibility in sheep and cattle. In one experiment four castrated male sheep and four non‐lactating cows were given diets of hay and of hay and concentrates, and in another experiment similar groups of animals were offered diets consisting mainly of hay or hay and lucerne cobs. In both experiments there was good agreement in digestibility between the sheep and cows. With diets which did not stimulate maximum rumination, sheep tended to ruminate for a longer time per day than cows. At high feed intakes rumination times were similar in sheep and cows. Times spent eating, ruminating or chewing per unit of feed DM were 6 to 19 times longer in the sheep than in the cows. Retention times of stained hay in the gut tended to be slightly shorter in sheep than cows and those of stained barley husk and of processed lucerne were similar in the sheep and cows. The median size of faecal particles was 1.4 to 1.9 times greater in cattle than sheep. The similarities and differences between sheep and cattle in the factors affecting digestibility are discussed.
Silage and milk production: a comparison between four rates of groundnut cake supplementation of silage of high digestibility
Authors: CASTLE M. E. , RETTER W. C. , WATSON J. N. , ZEWDIE E.
Published: April 2006

Grass silage made in late May from S24 perennial ryegrass was offered to twelve Ayrshire cows in a 16‐week feeding experiment. The silage had a DM content of 25.3%, a pH of 3.91, and contained 16.8% CP and 68.4% digestible organic matter in the DM. The silage was fed ad libitum and was the sole feed in the control treatment. In the other three treatments the silage was supplemented with a cube offered at rates of 0.8, 1.4 and 2.0 kg per 10 kg milk. The cube contained 82.2% groundnut, plus molasses and minerals, and had 37.9% CP in the DM. The daily intake of silage DM was 11.4 kg per cow on average over the four treatments which did not differ significantly. The mean daily milk yields were 14.8 kg per cow in the control treatment, and 16.5, 18.2 and 18.4 kg in the 0.8, 1.4 and 2.0 kg supplement treatments respectively. The SNF, CP and lactose contents of the milk were Wghest on the 1.4 kg supplement treatment. It is concluded that with a high digestibility silage, there is little evidence to support the feeding of more than 1.4 kg of high‐protein cubes per 10 kg milk in the declining phase of lactation.
Overgrazing and soil erosion on hill pastures with particular reference to the Peak District
Authors: EVANS R.
Published: April 2006

In a small drainage basin in the Peak District rates of soil erosion were measured between October 1966 and September 1968. The vegetated margins of ground denuded of vegetation (scars) were retreating by 9.3 mm per annum and rills and sheet wash removed annually from these scars up to 34 t ha−1 soil. Erosion was taking place primarily within Agrostis‐Festuca swards and also in heather moor, but not on peat‐covered slopes under cotton grass (Eriophorum vaginatum) moor. The Agrostis‐Festuca sward supported a higher sheep population than did the other vegetation types. In May 1974 most scars had been colonized by vegetation; this was related to a marked decrease in sheep numbers in 1969 and not to climatic factors.
The white clover contribution during the first 24 months after sowing
Authors: WILMAN D.
Published: April 2006

Perennial ryegrass was sown in a field trial with or without a small‐leaved white clover, S184, in September 1969 and cut five times per year in 2 successive years. Yield of clover was low and very unevenly distributed in time. Clover performance is described in four distinct periods, April‐June 1970, July‐September 1970, April‐June 1971 and July‐September 1971, in which yield of clover was respectively low, moderate, low and fairly high and the indirect contribution, the enhanced yield of other sward components, was respectively nil, moderate, moderate and moderate. The ratio of indirect to direct contributions on an annual basis concealed very large differences both within and between years. The presence of clover increased the N content but did not affect the P or K content of other sward components.
The effect of short‐term grazing of red clover on ewes at mating
Authors: DICKSON I. A. , FRAME J. , MACLEOD N. S. M. , KELLY MORAG
Published: April 2006

Four groups of ewes grazed swards of red clover (Trifolium pratense cv. Hungaropoly) for 28‐day periods ending 28, 14 or 0 (two groups) days before mating. One of the groups on red clover for the period immediately before mating continued on red clover during mating. At all other times before mating and for 7–8 weeks after mating commenced these ewes were grazed on a predominantly perennial ryegrass‐white clover sward. A fifth (control) group was on the ryegrass sward throughout. There was no apparent adverse effect of red clover on ovulation rate, conception rate or embryo mortality.