bluuebunny/crossref_metadata_2025_split huggingface dataset:
Supplementary feeding of forage to grazing dairy cows
Authors: PHILLIPS C. J. C. , LEAVER J. D. 
Published: April 2006

AbstractGrass silage was offered to continuously stocked dairy cows in two experiments. In the first 12 weeks of the grazing season (Experiment 1) 32 cows were offered grazed herbage only (G), or grazed herbage with a silage supplement offered for 45 min after morning milking (GMS), overnight at a restricted level (GRS) or overnight ad libitum (GAS). The two overnight treatments involved housing the cows between afternoon and morning milking. In late season (Experiment 2) 18 cows were used in a similar experiment lasting 9 weeks to compare treatments G, GMS and GAS. Within experiments the same level of herbage was available to all treatments (mean sward height 9.6 and 7.2 cm in Experiments 1 and 2 respectively).In Experiment 1, offering silage depressed herbage dry matter (DM) intake but had no significant effect on total DM intake. Silage (GMS, GRS, GAS) reduced milk yield but increased milk fat content and fat yield compared with G. In Experiment 2 offering silage depressed herbage DM intake but increased total DM and ME intakes. This led to increased milk yields, fat and lactose contents and liveweight gains, with the greatest benefit obtained when silage was available overnight.Silage was therefore beneficial in maintaining high DM intakes. Also, the substitution of silage for grazed herbage, particularly in Experiment 2, indicated that high stocking rates on grazing land can be maintained throughout the season, when silage is available ad libitum.
A quantitative model of the ensilage process in lactate silages
Authors: PITT R. E. , MUCK R. E. , LEIBENSPERGER R. Y. 
Published: April 2006

AbstractA model of the ensilage process is presented which can be used to predict silage quality in lactate silages. The model simulates the major microbial and biochemical processes during ensilage, including aerobic respiration, hydrolysis of hemicellulose. growth and death of lactic acid bacteria and their production of lactic and acetic acids, reduction in pH, change in soluble sugar content, increase in osmotic potential, and proteolysis. The model is designed to operate on mixtures of grasses, legumes, or whole‐plant corn. Parameters for the model are developed from published silage experiments and pure‐culture bacterial studies. The model gives reasonably accurate predictions of key silage quality parameters, but further experimental work is needed on growth of lactic acid bacteria and on plant‐enzyme proteolysis. Predicted final pH depends primarily on the pH at which bacterial growth and death rates are equal. Initial bacterial concentration affects the time to rapid pH change, while maximum bacterial growth rate affects the rate of decline thereafter.
Evaluation of faecal indices for predicting phosphorus status of cattle
Authors: HOLECHEK J. L. , GALYEAN M. L. , WALLACE J. D. , WOFFORD H. 
Published: April 2006

AbstractAn experiment examining the relationships between dietary and faecal phosphorus (P) concentration and intake and faecal output of P by steers is described. Six forages with a wide range of chemical properties were fed to six steers in a Latin square design. Dietary P concentration was highly associated with faecal P concentration in simple linear regression equations including (r2= 0.91) and excluding (r2= 0.94) animal variation. The regression slopes were similar to those in an Australian study involving dairy cows. However, the intercept values for the two studies differed. Phosphorus intake was well associated with daily faecal P output. Another study in Australia with steers showed similar results. However, the linear regression equation in the present study differed from that in the Australian study. Therefore, the application of a generalized equation to predict P intake from faecal P output is not advocated until the reliability of the equation in this study is confirmed with other forages.
The control of leatherjackets, Tipula paludosa Meig., in grassland by early application of insecticide
Authors: MOWAT D. J. , JESS S. 
Published: April 2006

AbstractTo determine whether leatherjackets might be controlled by application of a pesticide in summer, before oviposition by crane flies, chlorpyrifos was applied to perennial ryegrass (Lolium perenne) swards on dates from July to September in anticipation of leatherjacket infestation. Subsequent winter population estimates showed that leatherjacket numbers had been reduced by at least 85% by 0·72 kg chlorpyrifos ha‐1 applied on 13 July, and by 0·60 kg ha‐1 applied on 3 August or later.The significance of leatherjacket control by pesticide application on these dates is discussed in relation to previously recorded effects of pesticide treatment on other known pests. It is concluded that control of all common arthropod pests of proven significance in established grassland may be achieved with one application of pesticide.
The effect of herbage allowance on intake and performance of ewes suckling twin lambs
Authors: PENNING P. D. , HOOPER G. E. , TREACHER T. T. 
Published: April 2006

AbstractThe effect of herbage allowance on the herbage intake and performance of ewes and their twin lambs at pasture was investigated. Daily herbage allowances of 40,80.120 and 160 g organic matter (OM) kg‐1 ewe live weight, based on herbage mass measured to ground level, were offered during the first 12 weeks of lactation.The sheep were grazed rotationally around four paddocks of a perennial ryegrass pasture for 7‐day periods and herbage mass, extended tiller length and digestibility of the herbage consumed by the animals were estimated. Herbage intake by the ewes was estimated during weeks two to twelve and live weights were recorded weekly: during the last two weeks of the experiment grazing behaviour of one ewe on each treatment was recorded continuously.Herbage intakes by the ewes (164, 1–81, 2–42 and 268 ± 0153 kg d‐1) and live weight gains of the lambs (202, 245, 274 and 300 ± 7–3 g d‐1) increased with increasing herbage allowances. Herbage intakes by the ewes and growth rates of their lambs increased up to a herbage allowance which was over five times the amount of herbage eaten by the ewes.As the animals reduced herbage mass and sward height, biting rates by the ewes during grazing increased by 4 (± 0·08) bites min‐1 cm‐1 and masticating rates decreased. Mastications reached a maximum of 90 (± 3·5) min‐1 at a sward surface height of 9 cm.
The fitting of frequency distributions to height measurements on grazed swards
Authors: GIBB M. J. , RIDOUT M. S. 
Published: April 2006

AbstractHerbage height was measured in ryegrass/white clover (Lolium perenne/Trifolium repens) swards grazed by cattle using the rising plate meter or the sward stick. Ordinary single normal and double normal distributions were fitted to the data obtained. After the first 6 weeks of continuous grazing the double normal distributions fitted data for the taller swards better than the single normal distribution did, but for a short sward there was no improvement. There was no improvement due to the use of the double normal distribution with data for swards grazed by sheep.
Persistence of seeds of some grass species in cultivated soil
Authors: Roberts H. A. 
Published: April 2006

AbstractFreshly collected ripe caryopses of twenty‐five indigenous grasses were mixed with the top 7–5 cm of sterilized soil confined in cylinders sunk in the ground and cultivated three times yearly. There was a flush of seedlings of most species shortly after sowing, but species differed in the persistence of viable seeds. About one third, including Bromus sterilis, B. hordeaceus, Lolium perenne ssp. perenne, Arrhenatherum elatius and Alopecurus pratensis, produced few seedlings after the initial flush. Others such as Deschampsia cespitosa, Holcus lanatus and Poa trivialis, recognized as forming persistent seed banks in grassland soils, produced appreciable numbers of seedlings in the second year after sowing. Most persistent were species that occur as arable weeds (Avena fatua, Poa annua) or in wetlands (Glyceria plicata, G. maxima, Alopecurus geniculatus). Emergence from the seed bank generally followed soil disturbance but some species (Aira praecox, Avena fatua, A. sterilis ssp. ludoviciana, Danthonia decumbens) exhibited consistent seasonal patterns which may be associated with cyclic changes in germination requirements of the buried seeds.
Growth and production of a Cortaderia ptlosa (Gramineae) community in the Falkland Islands
Authors: McADAM J. H. 
Published: April 2006

AbstractAbove ground production of a typical Cortaderia pilosa dominant sward in the Falkland Islands was estimated over one growing season by summing significant positive increments in DM production of various sward components and by sequential cutting to ground level. The standing crop was characterized by a high proportion of standing dead matter at all times of the year. Net herbage production was estimated as 2200 kg ha‐1 and 1440 kg ha‐1 by the ‘difference’ and “sequential culling” techniques, respectively. The pattern of leaf growth was determined on another site by regular linear measurements of a population of physiologically similar C. pilosa leaves. There was very little early season growth and most of the DM was produced in a short period in the middle part of the growing season. The poor early season growth was attributed to adverse climatic conditions. A significant increase in green matter digestibility in October and November was masked by the low digestibility and high contribution to the overall DM by the standing dead component of the herbage.The implications of these findings are briefly discussed in relation to the increased utilization of C. pilosa by improved pasture management, including burning and possibly reseeding areas with improved species. Tissue turnover studies combined with more knowledge of sheep nutrition cycles would enable grazing systems to be developed on a sounder basis than previously.
Effects of vernalization on the subsequent rates of leaf extension and photosynthesis of perennial ryegrass (Lolium perenne L.)
Authors: Stapleton J. , Jones M. B. 
Published: April 2006

AbstractTemperature and daylength treatments have been used to investigate the apparent link between the potential for rapid leaf extension in spring and floral initiation and development in Lolium perenne (cv. Vigor). After growth at 5°C for 10 weeks (vernalization treatment) the leaves which developed at 15°C expanded significantly faster than non‐vernalized controls under both long and short days. Under long days floral development was initiated in vernalized plants but under short days it was not. Specific leaf area was higher in vernalized than non‐vernalized plants under long days.The photosynthetic capacity of leaves which developed on plants which had been previously vernalized and then grown at 15°C under long days was higher than non‐vernalized controls when expressed on a leaf area and dry weight basis, but not on the basis of chlorophyll content. Vernalization followed by short days resulted in a smaller and non‐significant increase in the photosynthetic capacity of leaves.Application of gibberellic acid (GA) as a spray to non‐vernalized plants did not affect floral development but did increase the rate of leaf extension. The application of GA did not affect specific leaf area or photosynthetic capacity expressed on an area basis.
A comparison of two cultivars of Holcus lanatus with Lolium perenne, under cutting
Authors: WATT T. A. 
Published: April 2006

AbstractThis work examined whether or not Holcus lanatus, cv. Massey Basyn, is an improvement on plants from German Commercial seed of this species and whether either could outyield Lolium perenne cv. Aberystwyth S23. The three grasses were sown in monoculture in a field near Oxford and received a total of either 250 or 500 kg N ha‐1 over two years. They were also sown with Tri‐folium repens cv. Blanca. The plots were cut 11 times over the 2‐year period at a height of 50 mm from ground level.At the high rate of nitrogen Lolium perenne always gave the highest yields of DM and DOM. In the second year, both types of H. lanatus gave higher yields than L. perenne at the low level of N. The L. perenne and T. repens mixture yielded more than that with H. lanatus and T. repens. H. lanatus depressed the yield of T. repens more than did L. perenne. H. lanatus h lanatus; Massey Basyn was affected less by rust infection than was German Commercial H. lanatus. At the final harvest, plots with r. repens contained more unsown grass than did N‐fertilized plots sown to grasses only.
The effect of lodging on 14C‐assimilate distribution after anthesis in Lolium perenne, CV. S24, grown for seed
Authors: HAMPTON J. G. , CLEMENCE T. G. A. , HEBBLETHWAITE P. D. 
Published: April 2006

AbstractField experiments in 1981 and 1981 examined assimilate distribution in lodged and non‐lodged plots of perennial ryegrass (Lolium perenne), cv. S24, grown for seed. Lodging was prevented either mechanically (1982 only) or chemically, by application of paclobutrazol (PP333) at 2 0 kg a.i. ha‐1. For each treatment, main‐tiller ears, stems and leaves and subtending vegetative tillers were fed with 14CO2 at 24 and 17 days after anthesis in 1981 and 1982, respectively, and the pattern of 14C‐assimilate export from each fed part was determined.Prevention of lodging increased assimilate movement to the ear from the flag leaf, although movement from main‐tiller leaves was primarily downwards to vegetative tillers. Assimilate movement to the stem was also increased because the cessation of stem elongation was delayed, especially where lodging was prevented by PP333. Both increases were at the expense of the tillers, although their number was not reduced in non‐lodged plots. Possible reasons for these changes in assimilate distribution are discussed.
Control of sward conditions and apparent utilization of energy in the buffer grazing system
Authors: ILLIUS A. W. , LOWMAN B. G. , HUNTER E. A. 
Published: April 2006

AbstractExperiments were carried out over four years to develop a system of buffer grazing. Groups of 16 cattle were set stocked with or without buffer areas formed by withholding a proportion of the grazing area by electric fence. It was found that buffers should be grazed if sward height, measured by rising plate meter, was reduced below 5 cm, or otherwise cut for silage. Increasing the area of the buffer reduced cattle gains but increased silage yield and sward quality, and the best compromise over 4 years was a buffer area of 25‐30% of the initial grazing area. Buffer treatments gave higher UME and financial output than controls, due to the value of silage from the buffers and to the higher nitrogen inputs which were successfully managed under buffer grazing. The higher outputs over 4 years were also associated with lower viability and therefore lower levels of risk, resulting from a number of compensating processes at sward and animal level. There was no indication that grazed UME was higher on buffer treatments at a given level of nitrogen, suggesting that any increased grazing efficiency must be offset by other disadvantages when comparing intensive with lax defoliation regimes. The results suggest that there is considerable stability in grazing systems which may frustrate attempts to improve their biological efficiency, although there is some scope for manipulating the seasonal pattern of land use and animal performance.
Effect of sample drying on the determination of fibre and water‐soluble carbohydrates of maize silage
Authors: PICCAGLIA ROBERTA , GALLETTI GUIDO C. 
Published: April 2006

AbstractNeutral detergent fibre (NDF), acid detergent fibre and water‐soluble carbohydrates (WSC) were assayed in wet and dry samples of maize silage, either treated with NaOH or untreated (control), before and after ensiling.Statistically significant effects of drying at 60°C were observed in WSC, NDF and cellulose estimations expressed on the basis of 105°C dry matter.It could therefore be preferable to analyse wet samples, as these are not altered by the degradations induced by oven‐drying and are more representative of the original condition of the forage.
The invertebrate fauna of grassland and its influence on productivity. III. Effects on soil fertility and plant growth
Authors: CURRY J. p. 
Published: April 2006

AbstractThe effects of grassland invertebrates on organic matter decomposition, soil fertility and plant growth are reviewed. Their role as primary decomposers is limited because of relatively low rates of metabolic and enzymatic activity compared with microorganisms. However, they greatly facilitate decomposition by fragmenting and incorporating litter into the soil and by stimulating microbial activity. Earthworms are the main litter consumers in productive temperate grasslands and termites in the tropics, while the activities of dung beetles, dipterous larvae and earthworms are essential for efficient dung decomposition. Earthworms and microbial‐feeding invertebrates facilitate mineralization and release into the soil solution of plant nutrients. Earthworms have a major influence on soil structure through burrowing, soil ingestion and mixing and they significantly increase plant growth.Herbivorous invertebrates at non‐outbreak densities normally consume less than 10% of net primary production in grassland, but consumption bears little relationship to overall effects on productivity. These depend on factors such as the nature of the damage caused and regrowth potential, tolerance for damage and effects on animal production at the time of attack. Sap feeding insects may cause wilting and reduced growth and selective feeding on preferred species can alter botanical composition, while aphid‐transmitted virus disease can depress yield. On the positive side, low levels of herbivory can stimulate growth, weed feeding insects may limit the distribution of pasture weeds, while the role of flower‐visiting insects can be important in the pollination of legume seed crops. Pest management approaches incorporating biological control, alteration of botanical composition, adjustment of stocking densities and accurately timed insecticidal applications offer prospects for the control of recurring pests such as grass grub and porina in New Zealand.
Interactions between fertilizer use and leatherjacket control in grassland
Authors: BLACKSHAW R. P. , NEWBOLD J. W. 
Published: April 2006

AbstractA coordinated experiment was set up in eight fields of established grass; four In Northern Ireland and four in the West of Scotland. At each site one of three different fertilizer rates (0, 75 and 150 kg N ha‐1) were applied to plots that had previously either received a 0.72 kg ha‐1 chlorpyrifos treatment to control leatherjackets or no spray. Both fertilizer and insecticide applications increased herbage yields. Yield increases in response to chlorpyrifos treatments were equivalent to that obtained from 75 kg N but were not linearly related to leatherjacket numbers. A curvilinear function relating loss per leatherjacket to population size was derived and its validity is discussed. It is concluded that herbage yield increases resulting from chlorpyrifos and nitrogen applications were independent and cumulative.
Application of double normal frequency distributions fitted to measurements of sward height
Authors: GIBB M. J. , RIDOUT M. S. 
Published: April 2006

AbstractHerbage heights were measured with a rising plate meter in mixed perennial ryegrass/white clover (Lolium perenne/Trifolium repens) swards maintained under five different systems of management. Double normal distributions fitted to the height frequencies were used to interpret changes over the grazing season in the mean heights of the shorter ‘frequently’ and the taller ‘infrequently’ grazed components of the sward, the variability of height within the two components, and the proportions of the two components in the sward. An attempt was also made to demonstrate that the overlap of these components, implicit in fitting double normal distributions, is a true reflection of the height distributions of frequently and infrequently grazed areas of the sward, and that the fitting of such a distribution provides a useful estimate of the proportion of a sward which is infrequently grazed.
The effects of a flexible grazing management strategy and leader/follower grazing on the milk production of grazing dairy cows and on sward characteristics
Authors: MAYNE C. S. , NEWBERRY R. D. , WOODCOCK S. C. F. 
Published: April 2006

AbstractAn experiment was carried out during 1984 to examine the effects of three alternative grazing strategies for January/February calved British Friesian dairy eows on sward and animal production. Cows were rotationally grazed across 1 d paddocks without concentrate supplementation from 30 April to 1 October. A flexible grazing (EG) treatment involved manipulating residual herbage height, as assessed by a rising‐plate sward stick, with cows initially grazing to 80 mm, reducing to 60 mm when milk yield declined below 20 kg d−1 and finally to 50 mm when milk yield declined below 15 kgd−1. Control (C) cows grazed to a constant residual herbage height of 60 mm throughout the season (a 60‐inm rising‐plate sward stick height is equivalent to a sward surface height of approximately 80 mm). On a further treatment a leader/follower (LF) approach was used, with cows paired for calving date and parity and within pairs allocated to either a high‐(leader) or a low‐yielding (follower) group, according to milk yield at turnout, with the leader group grazing 1 d ahead of the follower group. Overall stocking rates on C and LE treatments were identical but herbage allowances differed as a result of treatment effects.Animal performance data for the FG, C and LE treatments, respectively, were: milk yield (kg d−1) 14·5, 14·7 and 16·0 (s.e. 0·59); milk fat yield (g d−1) 577, 571 and 637 (s.e. 29); milk protein yield (g d−1) 528, 527 and 576 (s.e. 19); and liveweight gain (kg d−1) 0·09, 0·20 and 0·14 (s.e. 0·04).Overall, there was no benefit in animal production following lax grazing in spring even with high‐yielding cows, and this approach resulted in the accumulation of stem and senescent material in the sward in mid‐season. However, preferential treatment of high‐yielding cows by grazing as a leader group in a leader‐follower system resulted in higher milk production, particularly in late season, with an overall improvement in milk yield for the LF treatment of 9% relative to treatment C.
The effect of pesticide application on the establishment of white clover in a newly‐sown ryegrass/white clover sward
Authors: MOWAT D. J. , SHAKEEL M. A. 
Published: April 2006

AbstractIn plots of perennial ryegrass and white clover, regular treatment with chlorpyrifos and methiocarb more than trebled the clover content of the sward, compared with untreated plots, in just over 2 years from sowing. Chlorpyrifos alone accounted for most of the effect, which was attributed mainly to the control of Sitona lepidus. Combined treatment increased total herbage dry matter yield by 4·24 t ha−1 during this period but had little effect on grass‐only plots. Methiocarb appeared to have contributed by assisting earlier establishment of clover, but otherwise had little effect until slugs, which were initially uncommon, became more abundant in the later stages of the experiment. The effect of slug control was most noticeable in a cultivar of low cyanogenic potential. This factor did not influence the effect of chlorpyrifos.