bluuebunny/crossref_metadata_2025_split huggingface dataset:
The mineral metabolism of sheep fed high‐ and low‐magnesium selections of Italian ryegrass
Authors: MOSELEY G. , GRIFFITHS D. W. 
Published: April 2006

AbstractTwo experimental populations of Italian ryegrass selected for high and low magnesium content were established as swards, harvested fresh daily and offered to sheep. Chemical analysis of the crops showed a 44% higher Mg and a 22% higher Ca concentration in the high‐Mg selection but no significant differences between the selections for the other minerals.Blood and rumen contents were sampled throughout the feeding period and voluntary intake, digestibility and mineral balances for Na, K, Mg, Ca and P were determined. Magnesium intake, apparent availability and retention were significantly greater with the high‐Mg selection. There were no significant differences in the plasma‐mineral concentrations and all were within the normal range. Rumen fluid from animals fed the high‐Mg selection had a higher proportion of soluble Mg and a higher Na:K ratio in the supernatant liquor.
Orchardgrass and perennial ryegrass with applied nitrogen and in mixtures with legumes
Authors: SOLLENBERGER L. E. , TEMPLETON W. C. , HILL R. R. 
Published: April 2006

AbstractHigh‐yielding grass‐legume mixtures play an important role in forage‐animal systems but finding compatible and adapted species can sometimes be difficult. The objective of this study was to examine productivity of perennial ryegrass and orchardgrass in pure stands with N and in mixtures with legumes.Broadcast sowings were made on conventionally prepared seedbeds in August 1979 and May 1980 on a Hagerstown silt loam soil (fine, mixed mesic Typic Hapludalf). When sown alone orchardgrass cv. Pennlate and perennial ryegrass cv. Reveille received rates of N ranging from 0 to 448 kg ha−1 a−1. The grasses were also grown in mixtures with alfalfa cv. Arc, red clover cv. Arlington, or birds foot trefoil cv. Viking. The same legumes were sown alone. Four legume seed rates were used in both the pure legume and mixed stands.Orchardgrass‐N swards were more productive than ryegrass‐N swards over 3 years. More dry matter (DM) was harvested from pure stands of
An evaluation of the use of short‐term weight changes in grazing sheep for estimating herbage intake
Authors: PENNING P. D. , HOOPER G. E. 
Published: April 2006

AbstractA technique for estimating herbage intake by weighing sheep before and after grazing, with an allowance for insensible weight loss (IWL) was evaluated.Live weights were estimated by weighing each animal 200 times using an electronic balance and a microcomputer. This enabled each sheep to be weighed to ± 10 g and overcame the problem of fluctuation in weight due to movement. Mean rates of IWL in housed sheep were 2·3, 1·4, and 0·8 g min−1 for walking, standing eating or idling and when lying ruminating respectively. Intake rate (IR) estimated by weighing gave a small but significant bias of −0·8 g min−1 when compared with measurements of IR made using housed sheep. Estimates of IWL and IR were made with ewes grazing continuously stocked ryegrass swards maintained at surface heights of 3,6,9 and 12 cm. IWL was higher outdoors than indoors and tended to be higher on the longer swards. IR estimated by weighing gave similar results to those obtained using the chromic oxide technique. At a sward surface height of 3 cm, IR and total intake were lower than for taller swards and total time spent grazing decreased with increasing sward surface height.
Effect of nutrient application and herbicides on root competition between green panic seedlings and a Heteropogon grassland sward
Authors: COOK S. J. 
Published: April 2006

AbstractRoot competition was studied between seedlings of green panic (Panicum maximum var. trichoglume) and Heteropogon contortus in a native grassland sward clipped regularly to a height of 5·7 cm, and to which supplementary irrigation was applied. The influence of fertilizer addition and root competition from the grassland sward on seedling growth during the 42 days following emergence was determined. Root competition was excluded by steel tubes, or eliminated by killing the native sward with herbicides.Seedling growth was poor where neither root competition was controlled nor fertilizer was applied; at 42 days the seedlings were still less than 6 cm high with three leaves and one tiller. When root competition was controlled, either by steel tubes or herbicide, seedling growth increased significantly. Growth was greatest in the herbicide‐treated plots where fertilizer was applied, seedlings at day 42 being 48 cm high with sixty‐three leaves and nineteen tillers.Competition for nutrients appeared to be the primary factor limiting seedling growth and this was largely overcome by fertilizer application. Competition for nutrients appeared to increase the fertilizer requirements of pastures oversown into live swards compared with that of pastures oversown into herbicide‐treated swards.
The reaction of grazing sheep and cattle to the presence of dung from the same or the other species
Authors: FORBES T. D. A. , HODGSON J. 
Published: April 2006

AbstractAn experiment is described in which steers and wether sheep separately grazed perennial ryegrass swards, managed so that half of each sward had previously been grazed by sheep and half by cattle. The influence of the presence of dung from the same or the other species on grazing patterns and herbage utilization was examined.Regression analysis of extended sward height along transects laid across dung pats after grazing revealed that the limits of the rejected herbage were more clearly defined around cattle dung than sheep dung when grazed by cattle, whereas there was less distinct avoidance of herbage around both cattle and sheep dung when grazed by sheep. As grazing proceeded there was a progressive movement of animals from the half of the plot previously grazed by the same species to the half previously grazed by the opposite species, and this movement was more marked in the cattle than in the sheep.It was concluded that under mixed grazing a greater proportion of the herbage would be available to the sheep giving them an advantage over the cattle.
Supplementary feeding of forage to grazing dairy cows
Authors: PHILLIPS C J. C , LEAVER J. D. 
Published: April 2006

AbstractFor three 8‐week periods of the grazing season 48 spring‐calving cows were continuously stocked at either a high or a low rate (average 4.9 and 4.3 cows ha−1 respectively) which declined through the season. Within each stocking rate group half the cows were allowed access to hay for 45 min after morning milking; the other half received no hay.Total dry matter (DM) intakes were increased by offering hay, and intakes of hay were greater at the high stocking rate and during prolonged periods of inclement weather. However, there were times when, because of low herbage height and adverse weather, offering hay once daily could not prevent a decline in total DM intake. Grazing time was reduced and ruminating time increased by offering hay, but the rate of biting at pasture was unaffected. Hay DM was eaten at twice the rate of intake of herbage DM.Offering hay increased milk yield in early season and liveweight gain in late season. The benefits of offering hay were greatest for the higher yielding cows. There were no significant effects on milk composition.Stocking rate had only small effects on herbage height, but stocking at the higher rate tended to reduce herbage DM intake and reduced live‐weight gain in late season. Levels of utilized metabolizable energy from grazed herbage were high (average 106 GJ ha−1) but were reduced by feeding hay and stocking at the lower rate.
The effect of frequency of harvesting grass for silage on the intake and performance of beef cattle
Authors: STEEN R. W. J. , McILMOYLE W. A. 
Published: April 2006

AbstractTwo randomized‐block experiments were conducted to examine the effects of frequency of harvesting grass for silage on the intake and performance of beef cattle. In both experiments swards of S24 perennial ryegrass were harvested at 63‐, 49‐ and 38‐d intervals throughout the growing season. Grass harvested before and after 10 July was ensiled separately and termed spring and autumn silage respectively. In Experiment 1 the silages were offered ad libitum either unsupplemented or supplemented with 2 kg barley per head daily to eighty‐four Hereford‐cross weaned, single‐suckled steer calves of mean initial live weight 284 kg, in a 3 × 2 × 2 factorial design. Silage dry matter (DM) intakes and liveweight gains for the silages harvested at 63‐, 49‐ and 38‐d intervals were 4.80, 0.72; 4.49,0.76; and 4.62,0.78 kg d−1 for the spring silages and 4.69, 0.67; 4.59, 0.85; and 4.55,0.86 kg d−1 for the autumn silages respectively. There was no significant interaction between frequency of harvesting and concentrate supplementation. In Experiment 2 the silages were offered ad libitum and unsupplemented to forty‐two Hereford‐cross weaned, single‐suckled steer calves of mean initial live weight 240 kg, and forty‐two Hereford‐cross store cattle of mean initial live weight 356 kg, in a 3 × 2 × 2 factorial design. Silage DM intakes and liveweight gains for the silages harvested at 63‐, 49‐ and 38‐d intervals were 4.94,0.49; 5.69,0.80; and 619,0.93 kg d−1 for the spring silages and 5.50, 0.61; 5.57, 0.72; and 505, 0.65 kg d−1 for the autumn silages respectively. There were no significant interactions between frequency of harvesting and type of animal. It is concluded that a cutting interval of 49 d commencing on 21 May is likely to be optimum for this type of sward except under exceptional weather conditions.
A comparison of seed harvesting methods for perennial ryegrass treated with the growth retardant paclobutrazol
Authors: HAMPTON J. G. , HEBBLETHWAITE P. D. 
Published: April 2006

AbstractMethods of harvesting seed of perennial ryegrass cv. S24 treated with the growth retardant paclobutrazol applied at spikelet initiation at a rate of 2.0 kg active ingredient ha−1 were examined in 1982. The greatest seed yield (2202 kg ha−1) was obtained from swathing the crop at 35% seed moisture content and combining 2 days later, but this was not significantly different from that obtained from swathing at 48% seed moisture content or double direct combining at 35% seed moisture content. Seed yields from a single direct combining at either 35% or 25% seed moisture content were significantly lower than those of other treatments.
The combined use of fertilizer nitrogen and white clover on grazed ryegrass swards
Authors: REID D. 
Published: April 2006

AbstractA 1‐year grazing experiment with dairy cows is described in which the milk yield and herbage intake from a sward of S23 perennial ryegrass alone receiving fertilizer N at an annual rate of 360 kg ha−1 were compared with those from a ryegrass‐white clover var. Blanca sward given a total N application of 180 kg ha−1. Both treatments gave virtually the same total milk yield of about 12500 kg ha−1 over a 20‐week grazing season.
Use of a model to analyse the effects of continuous grazing managements on seasonal patterns of grass production
Authors: JOHNSON I. R. , PARSONS A. J. 
Published: April 2006

AbstractThe effects of management on the seasonal patterns of production of grass swards under continuous grazing are examined using a previously described mathematical model. For continuous set‐stocking it is observed that, if the leaf area index of the sward at turn‐out is too low, there may be a sustained reduction in animal intake throughout the season. Under continuous variable stocking, where the sward is maintained at a constant leaf area index, animal intake is observed to follow broadly a pattern determined by the environmental conditions. It is concluded that grass production, in terms of both gross tissue production and animal intake, is not independent of management. Furthermore, no evidence is found to suggest that the seasonal patterns of production undercutting and grazing are the same.
Effect of seed rate of red clover and of companion timothy or tall fescue on herbage production
Authors: FRAME J. , HARKESS R. D. , HUNT I. V. 
Published: April 2006

AbstractTetraploid red clover (cv. Hungaropoly) was sown at seed rates of 6,12 or 18 kg ha−1 alone and in mixture with timothy (cv. Scots) at 2, 4 or 6 kg ha−1 or with tall fescue (cv. S170) at 6,12 or 18 kg ha−1. Two ‘silage’ crops and an ‘aftermath grazing’ crop were harvested in 2 successive years. In harvest years 1 and 2, total herbage production levels of 11.12 and 7.47 t dry matter (DM) ha−1 respectively were obtained from pure‐sown red clover compared with 11.84 and 8.78 t DM ha−1 for red clover‐timothy and 12.23 and 9.64 t DM ha−1 for red clover‐tall fescue. Corresponding red clover production levels were 10.93 and 5.30 t DM ha−1 (red clover swards), 8.04 and 3.131 ha−1 (red clover‐timothy), and 6.42 and 109 t ha−1 (red clover‐tall fescue).Total herbage organic matter digestibility was improved by the timothy companion grass but not consistently by the tall fescue, whereas crude protein (CP) concentration was decreased by the addition of either grass. Increased seed rate intensified these effects, as well as the general effect of the companion grass in depressing red clover DM, digestible organic matter (DOM) and CP production.Total herbage DM, DOM and CP were not markedly affected by increasing red clover seed rate but red clover DM, DOM and CP were increased as red clover seed rate was raised, due to increases in the red clover component.The potential for silage cropping of red clover swards was confirmed but there was advantage in sowing a companion grass. Taking yield and quality parameters into consideration, timothy proved a better companion than tall fescue. A seed rate of 2 or 4 kg ha−1 timothy and 12 kg ha−1 red clover proved the most satisfactory.
The effects of silage harvesting system and supplementation of silage‐based diets by protein and methionine hydroxy analogue on the performance of lactating cows
Authors: GORDON F. J. , UNSWORTH E. F. 
Published: April 2006

AbstractThree silages were produced by harvesting grass using either a flail (F), double‐chop (DC) or a precision‐chop (PC) forage harvester. Each silage was ensiled unwilted and with formic acid additive applied at the mean rate of 2·2 1 t‐1 of grass. All three silages were well preserved and had mean particle lengths of 54, 49 and 26 mm and digestible organic ma er in dry ma er (DOMD) values of 0·67,0·66 and 0·66 for the F, DC and PC silages, respectively.The three silages were offered ad libitum to three groups each of 21 British Friesian cows, with a mean calving date of 29 January, from day 8 of lactation until 9 April. Within each silage group all cows were offered 4·1 kg dry ma er (DM) d‐1 of a control supplement divided equally in two feeds and given during milking. In addition, 24 kg DM d‐1 of the control supplement (C), a high protein supplement (HP) or a supplement containing methionine hydroxy analogue (MHA) were given at midday. The mean crude protein contents of the total supplementary feeds given were 193 253.and 195gkg for the C, HP and MHA treatments, respectively.The treatment effects showed no significant interactions between silage harvesting system and type of supplement. Silage harvesting system influenced milk yield, with the mean yields over the final 21 days of the experiment being 26·1, 27·4 and 25·5 kg d‐1 for the F, DC and PC silages, respectively, and the difference between DC and PC achieved significance (P <0·05). However, the milk from cows given DC had a significantly lower concentration of fat (P <0·01) and silage harvesting system had no effect on the yield of fat or protein. The type of supplement had no significant effect on milk yield, with the mean yields over the final 21 days of the experiment being 264, 267 and 259 kg d‐1 for the C, HP and MHA supplements, respectively.
An evaluation of effluent from grass silage as a feed for beef cattle offered silage‐based diets
Authors: STEEN R. W. J. 
Published: April 2006

AbstractFour experiments were carried out to evaluate effluent from grass silage as a feed for beef cattle. Castrated male cattle (steers) with mean initial live weights of 380,460 and 400 kg in Experiments 1–3 were offered effluent, in addition to a diet of grass silage given ad libitum and supplemented with cereal‐based concentrates. The cattle readily consumed effluent in preference to fresh water, the mean intake over the three experiments being 12·71 per head daily containing 0·77 kg dry matter (DM). Supplementation with effluent did not affect silage DM intake and increased total DM intake by 10%. Digestible energy concentrations of 13·1 and 16·6 MJ kg‐‐1 DM and organic matter, respectively, were determined for effluent in Experiment 4. There were no problems of ill health in any of the 69 cattle which were offered effluent. It is concluded that fresh or well‐preserved stored effluent from grass silage is readily consumed by beef cattle, is of high nutritive value and could enable savings to be made in total feed costs.
The effect of addition of sugar and inoculation with two commercial inoculants on the fermentation of lucerne silage in laboratory silos
Authors: SEALE D. R. , HENDERSON A. R , PETTERSSON K. O. , LOWE J. F. 
Published: April 2006

AbstractLucerne (DM 236 g kg‐1, WSC 49 g (kg DM)‐1) was ensiled in test‐tube silos with or without either glucose or fructose and with or without one of two commercial inoculants. The WSC content of the forage as ensiled was too low to obtain a well preserved untreated silage. By day 4 the pH values of the silages with added sugar or inoculant were significantly lower (P< 0·001) than the control silage. A satisfactory fermentation was attained only in the silages to which sugar and an inoculant had been added. These silages had a lower pH, more protein‐N (P< 0·001), less ammonia‐N (P<0·001), a faster increase in counts of lactic acid bacteria, and decrease in counts of coliforms than the other silages. Homo‐fermentative lactic acid bacteria dominated the fermentation in the inoculated silages while leuconostocs dominated the early stages of fermentation in the control silages. The results indicate that if there is insufficient sugar in the original crop, then the bacteria in an inoculant will not be able to produce enough lactic acid to lower the pH to an acceptable level. This has important implications for the ensilage of lucerne and other highly buffered low sugar crops.
The sulphur status of intensive grassland sites in southern Scotland
Authors: KEER J. I. , McLAREN R. G. , SWIFT R. S. 
Published: April 2006

AbstractField trials were carried out at five sites in southern Scotland to examine the sulphur status of intensively grown grass under varying Inputs of atmospheric and rainfall sulphur. Sulphur budgets were prepared by comparing amounts of sulphur removed at harvest with sulphur inputs from rainfall, the atmosphere and fertilizers.No yield responses to added sulphur were obtained, although soil‐derived sulphur was essential for the maintenance of optimal sulphur levels in herbage. Where no fertilizer sulphur was added, mineralization of soil organic sulphur supplied approximately 8 to 18 kg S ha‐1 annually during the growing season. Maintenance requirements of 5 to 10 kg S ha‐1 annually were indicated at the Dumfriesshire and Midlothian sites and 20 kg S ha‐1 annually at the Berwickshire sites to prevent a decline in soil sulphur reserves. Total sulphur concentrations of less than 2 g S kg‐1 dry matter were observed in herbage at some samplings indicating marginal sulphur sufficiency. Sulphate levels in herbage, expressed as a percentage of total sulphur, also indicated that sulphur supplies barely matched crop requirements.
Botanical composition of permanent grassland in England and Wales in relation to soil, environment and management factors
Authors: HOPKINS A. 
Published: April 2006

AbstractGrassland in England and Wales accounts for nearly 60% of the enclosed agricultural land and approximately 50% is at least 20 years old. Botanical composition, especially amongst older grassland, is extremely variable.A survey of 502 grassland farms was conducted in the 1970s. Factors affecting botanical composition of individual fields have been investigated using correlation and regression analyses and swards of similar botanical composition grouped using cluster analysis. Lolium perenne, Agrostis spp. and Holcus lanatus were numerically the most important species, contributing, on average, 35%. 21% and 10%, respectively. Most older swards contained Lolium perenne and Agrostis spp. in varying proportions depending on drainage, soil fertility and management. Swards containing a significant proportion of Trifolium repens were associated with adequate drainage, good soil nutrient status, low inputs of fertilizer nitrogen and hard grazing. Of the other common species Holcus lanatus was associated with poor drainage, low soil fertility, hay cutting, short‐season grazing and low fertilizer N. Festuca rubra was mainly in older swards, at higher elevations and with low fertilizer N but heavy stocking. Swards containing Rumex spp., Poa trivialis and other sown grasses were associated with mowing together with reasonably high soil fertility.
Effect of harvesting system on nutrient losses during silage making. 2. In‐silo losses
Authors: MAYNE C. S. , GORDON F. J. 
Published: April 2006

AbstractNutrient losses during the in‐silo period were determined following the ensiling of grass using three differing harvesting systems. The treatments were either (a) harvesting herbage directly by means of a flail harvester (unwilted flail, UF) or (b) pre‐mowing of herbage with a rotary drum mower and lifting using a precision chop forage harvester with wilting (WP) and without wilting (UP). Herbage was harvested and ensiled over the period 26–29 May 1982, and a good fermentation was achieved with all three silages. Losses of dry matter (DM), organic matter (OM) and crude protein (CP) during the in‐silo period were greatest with the UF system, intermediate with the UP system and lowest with the WP system. Gross energy losses followed the same trend with losses (as a percentage of ensiled levels) of 18·6, 9·8 and 4·4% for the UF, UP and WP systems, respectively. Gross energy loss as effluent accounted for 24% and 22% of total gross energy ensiled for the UF and UP treatments. Patterns of effluent flow differed between the two unwilted silages with a higher peak flow rate with the UF material. Total effluent production at 354 ml (kg DM ensiled)‐1 was greater for the UF material than for the UP material (288 ml (kg DM ensiled)‐1). Nutrient loss through surface waste was similar for all three silages whereas gross energy losses arising through residual respiration, fermentation and gaseous loss amounted to 149%, 6·7% and 31% of that ensiled for the UF, UP and WP silages, respectively. The results of this study, taken in conjunction with those of an earlier study where field losses were assessed, indicate that recovery of gross energy during silage making was very similar for the UP and WP systems and only marginally greater than that recovered with the UF system.