bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of contrasting perennial ryegrasses, with and without white clover, under continuous sheep stocking in the uplands
Authors: DAVIES D. A. , FOTHERGILL M. , JONES D.
Published: April 2006

Comparative sheep production from Aurora (very early‐flowering), Meltra (late‐flowering tetraploid) and Aberystwyth S23 (late‐flowering) perennial ryegrass (Lolium perenne L.) varieties was assessed as both grass‐only (200 kg N ha−1) and grass‐white clover (Trifolium repens L.) (75 kg N ha−1) swards under continuous stocking management. Beulah Speckled Face ewes and their Suffolk cross lambs were used from late April to mid‐July. From late July to early November only lambs grazed the pastures.

Mean (1985–87) total annual lamb production per hectare from Aurora and Meltra was 16% and 13% more than that from S23. The magnitude of the differences between these varieties and S23 declined from the first to the third year. Aurora gave 29% more lamb output per hectare than S23 in 1985 but only 10% more in 1987, while the advantage of Meltra over S23 fell from 19% in 1985 to 6% in 1987. Seasonal lamb production per hectare varied between the grasses, especially during spring when lamb output from Aurora was 43% and 22% more than that from S23 and Meltra respectively, with that from the tetraploid being 17% higher than that from S23.

It is concluded that the superior spring output from Aurora offers the farmer the opportunity to reduce his dependence on bought‐in feedstuffs, hence improving the efficiency and profitability of lamb production from grassland.
Yields and chemical composition of whole‐crop field beans and their components during pod‐filling
Authors: CABALLERO R.
Published: April 2006

Experimental trials in both rainfed and irrigated conditions were carried out in Central Spain with the aim of assessing the best time to harvest whole‐crop winter field beans for forage. Three times of harvesting during the pod‐filling phase were considered: seed with less than 20% DM (L,), 30‐35% (L:) and over 85% (Lj). At the early pod‐setting stage (Lj), the stems and leaves represented 75% of the total aerial biomass. At pod maturity (L3), this percentage was reduced to 27%. Over the same period, Lj to L3, the seed's contribution rose from 8% to 59%. Chemical composition of the different plant components varied markedly during the pod‐filling phase. Lignin in leaves and pod‐shells rose abruptly from 082 and 090% DM at L, to 7‐82 and 7‐01 % DM in L3. Crude protein of the seed varied only slightly between harvests. Mean DM yields over both years of 3 44 ± 0‐46. 607 + 071 and 428 ± 037 tDM ha‘ were obtained for the whole plants in rainfed conditions at the L1, L2 and L3 stages respectively. Corresponding values for irrigated conditions were 552 +0‐7I, 8‐66± M 6 and 684±082 tDM ha“'. Taking into account the chemical composition of the whole plant at the three times of harvesting (mean values in both conditions of 675, 657 and 641 g I00gDM‐’for DDM and 215, 18 7 and 186% DM for CP), it is concluded that the highest estimated energy and protein yields would be obtained by harvesting the plant at the Li stage (seeds with 30‐35% DM).
An evaluation of three bacterial inoculants and formic acid as additives for first harvest grass
Authors: KENNEDY S. J.
Published: April 2006

An experiment was carried out during 1984 to study the effect of treating grass at ensiling with three commercially available inoculant‐type additives (H/M Inoculant, Grass Sile and Siron), formic acid (850 g kg−1; Add‐F) or no additive on grass preservation, in‐silo loss, intake and animal performance. Primary growth grass ensiled from 28–29 May into concrete‐walled covered silos was of high dry matter (DM, 234 g kg−1), water‐soluble carbohydrate content (WSC. 212 g kg DM−1) and digestibility (MADF, 250 g kg DM−1).

The untreated silage displayed good preservation and with the exception of the Sirontreated silage which showed significantly lower buffering capacity (Be) and volatile fatty acid (VFA) contents than the untreated silage, the application of inoculant‐type additives did not improve silage preservation or decrease in‐silo DM losses. The formic acid‐treated silage displayed significantly lower Be, water‐soluble carbohydrate, ash, ammonia nitrogen (g kg total N−1) and lactate contents than the untreated silage.

After a 133 d storage period, silages were offered to finishing beef cattle for an 84‐d period. Cattle offered the silages displayed similar and non‐significant daily DM intakes, daily liveweight gains, dressing proportions and daily carcass gains. From this experiment it appears unlikely that any of the additives evaluated will improve animal performance relative to a well‐preserved untreated silage.
Sward composition, animal performance and the potential production of grass/white clover swards continuously stocked with sheep
Authors: ORR R. J. , PARSONS A. J. , PENNING P. D. , TREACHER T. T.
Published: April 2006

The potential productivity of perennial ryegrass/ white clover swards (GC) under continuous stocking management was assessed by comparing their performance, when grazed by sheep at sward surface heights of 3, 6 and 9 cm, with that of an all–grass sward (G) maintained at 6 cm and fertilized with 420 kg N ha–1 The grass/clover swards received no nitrogen fertilizer. The different grazing treatments had a marked effect on animal performance. In the first year for example, for treatments GC3, GC6, GC9 and G6–420 respectively, mean stocking rates to weaning were 19–7, 14–3, 8–9 and 18–4 ewes ha–1 (plus twin lambs); lamb growth rates were 223, 268, 295 and 260 g d–1and so total lamb live weight gain was 1054, 920, 630 and 1148 kg h a–1. The relative performance of the treatments was similar in all three years. All three grazing treatments had a similar effect on the composition of the grass/clover swards. Clover content increased in 1985, and was sustained in 1986 and 1987 during the main grazing season, although a marked decline in clover content during the winter led to a progressive long–term decline in both the proportion and the amount of clover.

It is suggested that a management based on maintaining a sward surface height close to 6 cm (as in all–grass swards) leads to optimum performance in grass/white clover swards grazed using continuous stocking with sheep. Despite the presence of a small and declining clover content, the output of the mixed grass/clover sward managed in this way was 80%, 80% and 82% of that of a grass sward supplied with 420 kg N ha–1 in 1985, 1986, and 1987 respectively and, similarly, 83% of the output in 1987 of a grass sward receiving 210 kg N ha–1.
Effects of treating lucerne with an inoculum of lactic acid bacteria or formic acid upon chemical changes during fermentation, and upon the nutritive value of the silage for lambs
Authors: PHILLIP L. E. , UNDERHILL L. , GARINO H.
Published: April 2006

A second cut of lucerne was wilted to 500 g DM kg−1 and either left untreated (control) or treated with formic acid (4.5 1 fresh forage t−1) or with a commercial inoculum of lactic acid bacteria (105 colony forming units (cfu) g forage−1). The forages were ensiled in 2‐t capacity silos for 8 months, and later fed to six lambs (mean initial weight 27.7 ±1.60 kg) in a 3x3 duplicated Latin square with 27‐d periods. Portions of the untreated and additive‐treated forages were also ensiled in laboratory silos at 25 ° C for intervals up to 42 d. Results from the laboratory silos showed that the major increase in ammonia‐N in silage occurred between 40 h and 7 d of fermentation; during this period, both formic acid and the inoculant produced a smaller increase in ammonia‐N, than did the control. The pH of inoculated silage declined from 5.74 to 4.57 in 7 d, but it took 14 d for the pH of the control silage to fall below 5.0. Formic acid treatment immediately reduced the silage pH from 5.74 to 5.10 (P < 0·01); the pH then remained unchanged until 21 d, after which it decreased slightly. When compared with control, lambs fed formic acid‐treated silage consumed more (P < 0·05) digestible organic matter; the response was associated with a trend towards decreased concentration of ammonia in plasma. Inoculation of lucerne silage did not (P < 0·05) affect voluntary intake but increased (P<0.05) apparent digestibility of fibre and tended to increase N retention.
Herbage productivity of brome grass (Bromus carinatus)
Authors: HARKESS R. D. , MORRISON M. W. , FRAME J.
Published: April 2006

Herbage production and quality of swards of brome grass (Bromus carinatus. Hook and Am) were compared with other commonly sown grasses at two sites in Scotland. At Ayr, the comparison was with perennial ryegrass (Lolium perenne L.), cocksfoot (Dactylis glomerata L.) and timothy (Phleum pratense L.) under 6‐cut (experiment 1) and 4‐cut (experiment 2) regimes over 3 years with 360 kg ha−1 fertilizer N applied annually in each experiment. At Edinburgh, brome grass was compared over 3 years with perennial ryegrass and cocksfoot under a 7‐cut system given 3(X)‐35O kg N ha−1 year−1 (experiment 3) and with perennial ryegrass, cocksfoot and Italian ryegrass (Lolium multiflorum Lam.) under a 4‐cut system given 250–325 kg N ha−1 annually (experiment 4).

Over the 3 years, brome grass gave 1.18, 6.19 and 1.3% less dry matter (DM) production than the other grasses in experiments 1, 2 and 3 respectively; in experiment 4, it was 1 % less productive than Italian ryegrass but 1.2% more productive than the other grasses. The organic matter digestibility (OMD) of brome grass was lower than that of perennial ryegrass but higher than timothy at Ayr, similar to perennial and Italian ryegrasses at Edinburgh but markedly superior to cocksfoot at both sites. N concentrations in brome grass were higher than in the ryegrasses but lower than in cocksfoot. Mineral composition data showed brome grass to be high in P and K, low in Ca and Mg and very low in Na compared with corresponding concentrations in the other grasses.

The variable performance of this brome grass species (B. carinatus) against commonly used grasses in the reported experiments, together with similar evidence from the literature, leads to the conclusion that it is unlikely to be suitable for widespread use in the UK; nevertheless, it has shown some promise in drought‐prone situations.
Effect of species and proportion of legume on herbage yield and nitrogen concentration of legume‐grass mixtures
Authors: MALLARINO A. P. , WEDIN W. F.
Published: April 2006

This study evaluated the relationships between legume proportion and dry matter (DM) yield, N yield, and herbage N concentration for three binary legume‐grass mixtures In Uruguay. Two identical trials were established, one in 1983 (Trial 1) and another in 1984 (Trial 2) and were evaluated for 2 years. Treatments were white clover (Trifolium repens L.) (WC), red clover (Trifolium pratense L.) (RC), and birds‐foot trefoil (Lotus corniculatus L.) (BT), each grown with tall fescue (Festuca arundinacea Schreb.) (TF) at four legume proportions, plus pure stands of TF. In Trial 1, annual DM yields of RC‐TF were greater than yields of WC‐TF or BT‐TF and in Trial 2 RC‐TF and BT‐TF yielded more than WC‐TF. The N concentration of either the legume or TF components usually was greater for WC‐TF than other mixtures in both trials. Annual DM yields in Trial 1 were optimized by legume proportions of 47 to 59% for WC, 62 to 67% for RC‐TF, and 57 to 100% for BT‐TF; and N yields were optimized by 70% of WC or RC, and by 100% BT. In Trial 2, which had greater soil‐N availability than Trial 1, optimum DM or N yields were achieved at lower WC proportions than in Trial 1. Changes in legume proportion did not affect legume N concentrations, but N concentration of TF in mixture was always positively and linearly related with legume proportion. It is concluded that DM yields for the first 2 years after seeding were greater for RC‐TF and BT‐TF than for WC‐based mixtures. Herbage DM and N yields of WC‐TF were optimized by lower legume proportions than for RC‐TF and BT‐TF. The N concentration of TF increased linearly with increasing proportions of any of the three legumes.
Effects of concentrate supplementation and herbage allowance on the performance of grazing suckling lambs
Authors: PRACHE SOPHIE , BECHET G. , THERIEZ M.
Published: April 2006

An experiment was conducted to examine the effect of concentrate supplementation on the performance of suckling lambs while grazing at variable levels of herbage allowance. Twenty‐four ewes suckling twin lambs were allocated 55 d after lambing between four grazing treatments (two levels of herbage allowance × two levels of supplementation) in a 2×2 factorial design. The sward consisted of Tall Fescue and was grazed rotationally.

Daily herbage organic matter (OM) allowances were 57.0 (H) and 38.5 (L) g OM kg LW−1 above 1·5 cm cutting height. Lambs were either supplemented (S) ad libitum with high‐moisture whole maize grain or unsupplemented (U).

Supplement intake during the 60‐d grazing period was 16 kg DM and 17.5 kg DM respectively for LS and HS lambs. The effect of supplementation on lamb growth rate differed significantly between allowances: at the low allowance level, supplementation increased growth rate (287 g d−1 vs 226 g d−1), whereas it had no effect at the high level (277 g d−1 vs 276 g d−1). Growth rate of unsupplemented lambs was significantly reduced at the low level of allowance compared to the high level (226 g d−1 vs 276 g d−1). The effect of sward height on time spent grazing by unsupplemented lambs is described during the defoliation of a plot.
The influence of crown rust (Puccinia coronata) on tiller production and survival of perennial ryegrass (Lolium perenne) plants in simulated swards
Authors: PLUMMER R. M. , HALL R. L. , WATT T. A.
Published: April 2006

Populations of Aberystwyth S23 and S24 ryegrass tillers were individually labelled and harvested at intervals to follow their life histories and productivity in response to the effect of infection with crown rust at two levels of nitrogen fertilization.

The number of tillers in a population was reduced as a result of infection with crown rust. Increased rates of tiller death due to the pathogen occurred throughout the population age‐range and were most pronounced in the youngest tillers. Population changes were evident following infection and continued to be apparent in the following spring. The disease caused alterations in sward age structure, leading both to a higher proportion of older tillers in the more rust‐damaged treatments and to a decrease in the weight of the herbage produced. It is concluded that rust infection of a sward may lead to changes in population structure with long‐term yield effects, in addition to the immediate direct yield reductions commonly reported. The significance of these results to the ecological and agronomic balance of grassland is discussed.
Contribution of white clover varieties to total sward production under typical farm management
Authors: EVANS D. R. , WILLIAMS T. A. , MASON S. A.
Published: April 2006

White clover varieties, potentially suitable for inclusion in seed mixtures for mixed stock‐rearing farm systems, were evaluated when growing with S23 perennial ryegrass under rotational sheep grazing with a silage cut in late May or early June, as practiced on farms. Monoculture grass swards were also included to enable the direct and indirect contribution of white clover to total sward production to be evaluated.

White clover increased total sward production during all three years of the trial by an average of 50%. Although clover content of swards were similar, large differences occurred in their grass content, especially in the third year, when difference in total yields of swards based on large–leaved clover varieties was 2 t ha −1 while difference in clover yield was only 0‐6 to ha–1 The indirect contribution of white clover, namely the extra grass resulting from N transfer, was greater in the spring than in the autumn. It was also greater for Nesta than for other varieties. and exceptional for this variety in that the increase in grass yield above that of grass monoculture was maintained over three harvest years.
A simulation model of the microbiological and chemical changes accompanying the initial stage of aerobic deterioration of silage
Authors: COURTIN M. G. , SPOELSTRA S. F.
Published: April 2006

A mathematical model is presented that predicts the time‐course of aerobic deterioration in grass and whole‐crop maize silages. The model predicts the stability of the silage taking into account the buffering capacity of the silage, the initial contents of organic acids and ethanol, pH, the initial temperature and the initial populations of the microorganisms. The specific processes simulated include the growth of yeast and acetic acid bacteria, the oxidation of fermentation products, the consumption of oxygen and the production of carbon dioxide, the rise in temperature. and the increase in pH.

The deterioration of silage is seen to be initiated by acetic acid bacteria or by yeast, or by both groups together. The factors that determine which groups will prevail are the dry matter contents and the chemical composition of the silage. The output of the model is validated by comparison of the simulated data with data from published work on the deterioration of silage.
An evaluation of the effects of grazing management systems involving preferential treatment of high‐yielding dairy cows on animal performance and sward utilization
Authors: MAYNE C. S. , CLEMENTS A. J. , WOODCOCK S. C. F.
Published: April 2006

Two systems of grazing management involving preferential treatment of high‐ yielding dairy cows were compared with a grazing system in which both high‐ and low‐yielders received uniform treatment. Cows were rotationally grazed across I‐day paddocks without concentrate supplementation from 23 April to 8 October 1985, with a mean stocking rate over the season of 5‐4 cows ha−1. Preferential treatment of high‐yielding cows was achieved either by using a leader/follower approach (LF) with high‐yielding cows in the leader group, or by preferential forage feeding (PFF) where high‐yielding cows were allowed access to grass silage for 1 ‐5 h daily and grazed alongside low‐yielders. Control (C) cows grazed together as a single group. The high grazing stocking rates used on all three treatments resulted in good grass utilization with residual sward heights, assessed by a rising‐plate sward stick, of 45, 50 and 48 mm for the LF, PFF and C treatments respectively. Animal performance data for the LF, PFF and C treatments respectively were: milk yield (kg d−1) 15middot;1, 15middot;6 and 14middot;7 (s.e. 0middot;78); milk fat yield (g d−1) 598, 606 and 567 (s.e. 34); milk protein yield (g d−1) 500, 519 and 480 (s.e. 31); and live weight gain (kg d−1) 0middot;12, 0middot;23 and 0middot;25 (s.e. 0·05). These results indicate that leader/follower grazing had little overall effect on animal performance when high grazing severity was imposed, with the improvement in animal performance of high‐yielding cows in the leader group being offset by the reduced performance of the follower group. Buffer‐feeding of high‐yielding, rotationally‐grazed cows with high‐quality grass silage had little effect on animal performance and resulted in a decrease in the efficiency of grassland utilization. Silage appeared to substitute for herbage, with a reduction in herbage DM intake of 0middot;55 kg per kg silage DM consumed.
Effect of agrochemical applied at sowing on seedling emergence and herbage yield of perennial ryegrass and white clover
Authors: LEWIS G. C. , COOK R. , van der ENDE A.
Published: April 2006

Plots of white clover (Trifolium repens) and perennial ryegrass (Lolium perenne) white clover were sown with and without fungicide seed treatment, seed treatment with Cytozyme (a proprietary growth‐promoting agent) and pesticide granules (carbofuran or carbosulfan) mixed with the seed. Sowings were made in April/May at Hurley (1986 and 1987), Dorchester (1987) and Bronydd Mawr (1987). Only treatments containing pesticide significantly improved seedling emergence or herbage yield in the 1986 sowing. In 1987, pesticide greatly increased seedling emergence of ryegrass and clover at Hurley and Dorchester, but had no effect at Bronydd Mawr. At Hurley, herbage yield and the proportion of clover were more than doubled for up to a year, by chemical treatment after sowing in 1986.

Populations of plant parasitic nematodes were recorded at all sites and it is suggested that at Hurley and Dorchester seedlings with nematode damage were unable to survive the dry soil conditions that prevailed. In a subsequent pot experiment, pesticide granules controlled root endoparasitic nematodes and significantly increased seedling emergence of white clover in dry soil but had no effect in moist soil.
Enzymes as silage additives 2. The effect of grass dry matter content on silage quality and performance in sheep
Authors: JACOBS J. L. , COOK J. E. , MCALLAN A. B.
Published: April 2006

Eight grass silages were made from two contrasting varieties of perennial ryegrass, four silages each from a late‐cut early‐maturing (high dry matter, HDM) variety and from an early‐cut, late‐maturing (low dry matter, LDM) variety. The grass was ensiled without additive (untreated), or with formic acid, or with one of two enzyme mixtures of hemicellulases and cellulases (enzyme 1 and enzyme 2) for a period of 130 d.

Formic acid‐treated silage had lower levels of lactic acid at both levels of dry matter than the other silages. Enzyme treatment of grass prior to ensilage resulted in reduced levels of cellulose, acid‐detergent fibre and neutral‐detergent fibre in LDM silages and lower acid‐detergent fibre and neutral‐detergent fibre in the HDM silages compared with the corresponding untreated and formic acid‐treated silages. Voluntary intakes (g DM d−1) of untreated and enzyme‐treated silages were significantly (P<0·01) lower at both digestibilities compared with formic acid‐treated silages (LDM: untreated, 982; formic, 1069; enzyme 1, 868; enzyme 2, 937; HDM: untreated, 931; formic, 1027; enzyme 1, 943; enzyme 2, 914). The organic matter, carbohydrate and nitrogen digestibility coefficients of LDM silages were significantly (P<0·001) higher than those of HDM silages. There were no significant differences in any component digestibility related to silage additive.

Comparison of digestibility coefficients for constituents of the LDM silages fed to sheep or steers showed no differences between species.
A new descriptive scale for early reproductive development in Lolium perenne L.
Authors: SWEET N. , WILTSHIRE J.J.J. , BAKER C.K.
Published: April 2006

Early reproductive development in Lolium perenne L. has been widely used for defining growth stages in spring, and this has been useful in managing seed crops and in trials involving the use of growth retardants.

A numerical scale for apical development based on morphological criteria, has been successfully used in research. The scale identifies eleven clearly recognizable stages of apical development, from the vegetative apex through to the immature, but completely‐formed spike. It is intended that the key should be used to identify consistantly precise stages in apical development.
Relationship between climatic factors and the dry matter production of swards of different composition at two altitudes
Authors: MENZI H. , BLUM H. , NÖSBERGER J.
Published: April 2006

The growth of a timothy sward, a timothy/white clover mixture and a multi‐grass/white clover mixture were compared and related to climatic factors at two sites of different altitudes.

Temperature and radiation had a greater effect on sward growth than did species composition or management. If the reproductive and vegetative growth periods were studied separately, then more than 90% of the variation in yield could be explained by temperature and radiation. During spring reproductive growth, yields per unit increment of temperature or radiation were 2–3 times higher than during summer vegetative growth. Spring growth was affected more by temperature than by radiation and the lower yields at the higher altitude were also related to lower temperatures.
Spatial heterogeneity and other sources of variance in sward height as measured by the sonic and HFRO sward sticks
Authors: HUTCHINGS N. J.
Published: April 2006

Measurements of undisturbed sward surface height (sward height) were made using the HFRO and sonic sward sticks at 20 cm intervals along 100 m transects laid across paddocks grazed by either sheep, cattle or goats. Measurements of sward height were also made at 5 cm intervals along 10 m transects laid across the same paddocks using the HFRO sward stick alone. The variance of the measurements from each transect was partitioned across the range of spatial scales of roughness present using spectral analysis. The variance of the sward surface height appeared to be dominated by variation with spatial scales of less than 1 to 2 m. The variances of measurements made with the two sward sticks were similar despite the greater sampling area of the sonic sward stick. This was due to the presence of variation at spatial scales much larger than the sampling area of either instrument and to a greater contribution from non‐spatially related sources to the variance of the sonic sward stick measurements. The use of weighted disc meters for obtaining the mean height of continuously grazed sward deserves re‐examination, while automation of the sonic sward stick may be worthwhile if the spatial distribution of herbage is to be described.
Influence of bacterial inoculant and substrate addition to lucerne ensiled at different dry matter contents
Authors: JONES B. A. , SATTER L. D. , MUCK R. E.
Published: April 2006

Field‐wilted lucerne was chopped with a forage harvester at 33 ± 1·5, 43 ± 2·0 and 54 ± 1·8% dry matter, treated and ensiled in laboratory silos during four cuttings in each of two years. Treatments were control (C), sugar addition at 2% of fresh weight (S), inoculum applied at 3 × 105 bacteria g−1 herbage (I), and sugar and inoculum combined (IS). Duplicate silos were opened and analysed after 1, 2, 3, (4 or 5), 7, 14 and 60 d of fermentation. The initial rate of proteolysis of lucerne protein decreased with increasing dry matter (DM) content of the lucerne, and was not influenced by the year, cutting or silage treatment. Inoculation increased (P<0·05) the rate of pH decline for all silage dry matters, and shortened the lag time prior to pH decline with 33 and 43% dry matter silages. Sugar addition had no effect on rate of pH decline or lag time. Inoculation and sugar addition both lowered final pH, acetic acid, ammonia (NH3), free amino acids (FAA) and soluble non‐protein N (NPN) in silages (P<0·01) and increased lactic acid content with 33 and 43% dry matter silages. Only inoculation was beneficial at 54% DM with no difference between I and IS. The influence of forage characteristics (epiphytic lactic acid bacteria, buffer capacity and sugar:buffer capacity ratio) on treatment effectiveness varied with dry matter content.
Reseeding in the Falkland Islands. Herbage production of a range of grass species and cultivars
Authors: DAVIES T.H. , RILEY JANET
Published: April 2006

The productivity of 20 cultivars from a range of 13 grass species was compared by harvesting four times during each of three successive growing seasons. In the experiment, 120 kg N ha−1, 42 kg P2O5 ha−1 and 42 kg K2O ha−1 were applied annually.

Mean annual yield was 3229 kg DM ha−1 and 2147 kg DOM ha−1. Cultivars were arranged in seven groups for comparison. Three of the groups, Lolium, Phleum and ‘others’ (the latter consisted of Festuca arundinacea cv. Dovey and Poa pratensis cv. Bensun A.34) appeared significantly lower yielding than the Dactylis, Festuca (fine‐leaved), Agrostis and Holcus groups.

In the Lolium group, cv. Gremie outyielded cv. Melle every year. No cultivar of Dactylis was significantly better than any other in its group. Phleum CVS Motim and Eskimo were similar and superior to cv. S.50. Festuca ovina cv. Novina and Agrostis canina cv. Kingstown were marginally the best in their respective groups. The two cultivars of Holcus performed virtually identically. Festuca arundinacea cv. Dovey was a good producer of early spring grass. Poa pratensis cv. Bensun A.34 was generally low yielding and subject to fungal rust attack in autumn. The pattern of seasonal DM production was 16% in early spring (cut in October/November), 39% in mid‐season (cut in December), 40% in late summer (cut in February/March) and 5% in autumn (cut in April/May). Quality of the herbage was superior to the main indigenous grass Cortaderia pilosa.

It was concluded that although the experiment was conducted under a cutting regime it provided useful guidance for seeds mixture formulation and stock carrying capacity calculations.
The comparative performance of Holcus lanatus and Lolium perenne under sheep grazing in the Scottish uplands
Authors: MORTON J. D. , BOLTON G. R. , HODGSON J.
Published: April 2006

An experiment was conducted over 3 years (1983‐85) to assess the performance of Holcus lanatus German Commercial and cv. Massey Basyn compared with Lolium perenne cv. Perma on a gley soil under sheep grazing in the Scottish uplands. All grasses were sown together with Trifolium repens cv. Grasslands Huia. The swards were rotationally grazed at similar herbage allowances. During the first harvest year, the swards were grazed hard to a low mass (500 kg DM ha−1). In the second harvest year, post‐grazing herbage masses of 500 and 1000 kg DM ha−1 were compared.

Perma ryegrass had a higher level of herbage production than both H. lanatus cultivars in the first and second harvest years after sowing and hence had a greater number of sheep grazing days. The ryegrass sward consisted of 25% more green sown grass (85 cf. 60%) but 12% less white clover (4 cf. 16%) compared with both H. lanatus cultivars in the establishment and first harvest years. The persistence of all three grasses was poor although ryegrass had a higher presence (36%) than either Massey Basyn (22%) or German Commercial (13%) at the end of the. second harvest year.

At a similar herbage allowance, there were no significant differences in the herbage intake and liveweight gain of sheep. Ryegrass had a higher organic matter digestibility and lower neutral and acid detergent fibre and lignin contents than either of the H. lanatus cultivars.

In the second harvest year, although herbage production was greater at the higher herbage mass, there was no difference in the proportion of sown grass.

It was concluded that ryegrass is a superior grass to H. lanatus on upland soils with high N status, moderate P status and a high pH.
The effects of poloxalene on ingestion by cattle grazing Lucerne†
Authors: DOUGHERTY C. T. , COLLINS M. , BRADLEY N. W. , LAURIAULT L. M. , CORNELIUS P. L.
Published: April 2006

The mechanisms that terminate meals of cattle grazing lucerne (Medicago sativa L.) are not well defined. Sub‐acute bloat may lead to cessation of grazing and, consequently, surface active substances used in the treatment and prevention of bloat, such as poloxalene, may extend grazing meals and increase herbage intake. Twelve mature Angus cows (Bos taurus) were offered 0, 12·5 and 25·0 g poloxalene in 0·5 kg of crushed maize (Zea mays L.) kernels each day, immediately before two consecutive 1‐h measured parts of a grazing meal on 21‐ to 24‐day‐old lucerne swards with a herbage dry matter (DM) mass (> 5 cm) of 2·03 t ha−1 and herbage DM mass allowance of 3·55 kg hd−1h−1. Total herbage DM intake was 2·52 kg hd−1 during the first hour and 1·54 kg hd−1 during the second hour of the 2‐h grazing meal. Differences in herbage intake were attributable to a cessation of grazing. Mean rates of biting were 26·3 and 14·8 bites min−1 and mean DM intakes per bite were 1·82 and 4·38 g during the first and second part of meals, respectively. Poloxalene treatments caused a small linear decline in grazing time during the first part of meals and a larger increase in grazing time during the second part of meals. Lower rates of DM intake caused by poloxalene were offset by increases in grazing time. It was concluded that poloxalene moderated ingestive behaviour within grazing meals of immature lucerne and this response may have been at least partly due to the relief of sub‐acute bloat.
Animal production evaluation of herbage varieties. 1. Comparison of Aurora with Frances, Talbot and Melle perennial ryegrasses when grown alone and with clover
Authors: MUNRO J. M. M. , DAVIES D. A. , EVANS W. B. , SCURLOCK R. V.
Published: April 2006

Comparative herbage characteristics and sheep production (ewes and lambs until weaning and lambs thereafter) from swards of Aurora (very early flowering), Frances (early flowering), Talbot (intermediate flowering) and Melle (late flowering) varieties of perennial ryegrass (Lolium perenne) were studied under a continuous variable stocking management based on sward surface height guidelines. The varieties were assessed as grass‐only (215 kg N ha−1 fertilizer) and grass/clover (83 kg N ha−1 fertilizer) pastures.

Over 2 years (1985‐86) total annual lamb production per hectare from grass‐only swards of Aurora was 19% more than that from Frances despite similar herbage productivity. Differences between the varieties in lamb output were more pronounced as grass/clover swards, with Aurora producing 29 and 18% more lamb than Melle and Talbot respectively and with Frances also giving 16% more than Melle. Overall lamb production from grass/clover swards was 10% more than that from the grass‐only pastures, mainly due to 69% advantage in individual lamb growth rates after weaning. Herbage organic matter digestibility, during the post‐weaning period, was higher on grass/clover than on grass‐only swards, and similarly with Aurora versus the other varieties. Under a frequent cut simulated grazing regime the relative herbage productivity of the four varieties differed, with Aurora 13% less productive than Frances.

The results are discussed in relation to the limitations of assessing performance under cutting, and the significance of the interaction in animal productivity between the two sward types.
The effect of row spacing and cover‐crop on stolon development and the seed yield components of white clover cultivars of contrasting leaf size
Authors: HOLLINGTON P. A. , MARSHALL A. H. , HIDES D. H.
Published: April 2006

Three white clover cultivars, S184 (small‐leaved), Menna (medium‐leaved) and Olwen (large‐leaved), were broadcast or sown in 15, 30 or 60 cm drills at a seed rate of 3 kg ha‐1. The three cultivars were either sown without a cover‐crop or sown under a cover‐crop of spring barley (cv. Crescent) or peas (cv. Countess). The effects of these methods of establishment on the stolon growth and components of seed yield were subsequently measured.

Stolon growth and development was influenced by row spacing, cultivar and season. The overall plant response at all but the widest row spacing (60 cm) was to increase stolon growth such that inflorescence production, the number and proportion of ripe inflorescences and the other seed yield components were unaffected by row spacing. Cultivars differed in their response to row spacing. Cultivar Olwen produced most inflorescences and more ripe inflorescences when broadcast, cv. S184 when sown at 60 cm row spacing and cv. Menna at 15 or 30 cm row spacing. Cultivars also differed in their response to cover‐crop, with cvs Menna and S184 producing more inflorescences and more ripe inflorescences when sown under barley and peas than when pure sown. The inflorescence production of cv. Olwen was not influenced by cover‐crop.

The relationship between vegetative and reproductive growth is discussed in relation to establishment, cultivar and climate and the possible implications for the establishment of white clover seed crops in the UK.
A comparison of formic acid and an acid‐salt type additive on the performance of dairy cows in early lactation
Authors: DAVIES O. D. , HAIGH P. M.
Published: April 2006

Perennial ryegrass, harvested as second‐cut material on 10 and 11 July 1990, was treated with either formic acid at 31 t‐1 or an acid‐salt type additive at 61 t‐1 and ensiled in roofed 150 t bunker silos. Subsequently both silages underwent a predominantly lactic fermentation. Nevertheless the acid‐salt‐treated silage had a significantly higher quantity of formic acid (19 vs 12 g kg DM‐1) and significantly lower levels of lactic (98 vs 118 g kg DM‐1) and acetic acid (11 vs 17 g kg DM‐1) compared with formic acid‐treated silage. In‐silo losses and effluent production were similar.

Each silage was individually fed to 10 October‐calving Friesian dairy cows (average weight 565 kg) from weeks 2 to 15 of lactation, together with 3 kg d‐1 of a compound feed containing 190 g kg DM‐1 crude protein and with an estimated metabolizable energy content of 12·6 MJ kg DM‐1. The acid‐salt additive had no significant effect on silage DM intake, daily milk yield, milk protein or cow liveweight change, but significantly increased milk butterfat content compared with formic acid‐treated silage.

It is concluded that the acid‐salt type additive produced little difference in terms of either silage fermentation or animal performance compared with formic add treatment.
Accelerated drying of cut lucerne (Medicago sativa L.) by chemical treatments based on inorganic potassium salts or alkali metal carbonates
Authors: MEREDITH R. H. , WARBOYS I. B.
Published: April 2006

Liquid treatments to accelerate drying were applied to lucerne under laboratory conditions by brief immersion (∼3s) of cut shoots. Aqueous solutions of the alkali metal carbonates Li2CO3, Na2CO3 and K2CO3 were found to reduce drying times to 33% moisture content (MC) on a dry weight basis (dwb) by 45%, 55% and 65% respectively. Effectiveness was related to the ionic radius of the cation.

From a range of potassium salts (KCl, K2CO3, KHSO4, KOH, K2SO4) in aqueous solution, the only useful reductions in drying time to 33% MC (dwb) came from the alkaline KOH (68%) and K2CO3 (65–76%).

It is considered that K+ has a specific function in increasing water loss through the plant cuticle and that association with CO32‐ provides the high pH necessary for this activity.

An aqueous solution of K2CO3 (0·16 M) gave greater acceleration of drying than the organic solvent petroleum ether and no benefit was gained by combining these treatments. Addition of a surfactant did not improve the effectiveness of K2CO3 as a desiccant but mixing with a rape‐seed oil emulsion reduced the drying time to 33% MC (dwb) by 11% relative to K2CO3 alone.

Under field conditions K2CO3 as an aqueous solution gave only small reductions in the drying time to 33% MC and effectiveness was reduced by the addition of the rapeseed oil emulsion.

Better results with K2CO3 (aq) might have been achieved with a more ventilated swath structure but the results strongly suggest that the oilseed rape emulsion is unlikely to improve the effectiveness of K2CO3 under field conditions.
Assessment of contrasting perennial ryegrasses, with and without white clover, under continuous sheep stocking in the uplands. 5. Herbage production, quality and intake in years 4–6
Authors: DAVIES D. A. , FOTHERGILL M. , MORGAN C. T.
Published: April 2006

Herbage characteristics were studied over years 4–6 (1988–90) in three perennial ryegrass (Lolium perenne L.) varieties as grass‐only (200 kg N ha‐1) and grass/clover (Trifolium repens L.) swards which received 75kg N ha‐1 in 1988 and 0kg N ha‐1 in 1989 and 1990 when continuously stocked with sheep. Mean total annual herbage production of Aurora, a very early flowering variety, was 11% more than that of late‐flowering Aberystwyth S23 due to 21% higher growth as grass/clover pasture. The grass/clover sward of Meltra, a tetraploid late‐flowering variety, out‐yielded S23/clover by 17%. Herbage production of grass/clover was 86% of that of grass only in 1988 but only 54% of the grass‐only swards averaged for 1989 and 1990.

In vitro organic matter digestibility (OMD) of Meltra was 38g kg‐1 OM and 27g kg‐1 OM higher than that of S23 and Aurora respectively. OMD of grass/clover was 15g kg‐1 OM higher than that of grass only during the post‐weaning period. Herbage intake was positively correlated with OMD of herbage.

The herbage attributes were related to lamb performance reported previously. Lamb output was positively correlated with intake of digestible organic matter.

Differences between the three varieties in herbage characteristics were greater as grass/clover than as grass‐only swards, reflecting their compatibility with white clover. In this respect Meltra was the best and S23 the poorest variety.
A practical equation for pasture growth under grazing
Authors: CACHO O. J.
Published: April 2006

A sigmoid equation that accurately describes pasture growth is presented. The equation has three parameters that can be estimated either statistically from experimental results or algebraically from physiological simulation models. The equation produces satisfactory statistical results and it can account for different environmental conditions, through adjustment of parameter values, making it ideal for incorporation into grazing models when a simple but flexible equation is needed.
The digestion of grass silages produced using inoculants of lactic acid bacteria
Authors: SHARP R. , HOOPER P. G. , ARMSTRONG D. G.
Published: April 2006

The purpose of this study was to evaluate the efficiency of two inoculants of lactic acid bacteria (LAB) on grass silages. The evaluation was made in terms of silage composition, rumen fermentation, digestion and animal production. Over a 2‐year period two lots of silage were prepared in two 100‐tonne capacity clamps. In each case an untreated silage and an inoculant‐treated silage were prepared simultaneously from an identical herbage source using independent sets of silage‐making equipment. The inoculant used in the first year was Pioneer Brand 1188 (Pioneer Hi‐Bred UK), and in the second year a slightly different inoculant from the same source (Pioneer Hi‐Bred) was used. The two inoculants were essentially similar in composition, comprising a mixture of Lactobacillus plantarum and Streptococcus faecalis; the strains included in the second inoculant were selected for their capacity to tolerate higher temperatures. The fermentation of the inoculant‐treated silages appeared to be dominated by homofermentative LAB compared with the untreated silages. The use of either inoculant was associated with a change in the rumen volatile fatty acid (VFA) pattern, with a significantly greater molar proportion of propionate and a corresponding reduction in both acetate and butyrate. There was a trend indicating an enhanced efficiency of microbial protein synthesis within the rumen of the heifers for the inoculant‐treated silages, although this was only significant when concentrate was offered with the silage in one experiment. The inoculant‐treated silages had significantly greater intake characteristics than did the untreated silages, though this was not reflected in a statistically significant improvement in average daily liveweight gain in either year.
Reseeding in the Falkland Islands: seed rate and fertilizers for establishment
Authors: DAVIES T. H. , RILEY JANET
Published: April 2006

Five experiments were carried out to measure the effects of seed rate and fertilizers on the establishment and early growth of reseeded grass mixtures in the Falkland Islands.

Experiments 1 and 2 compared seed rates within the range 7·5‐35kg ha−1. Experiment 3 assessed the effects of three levels of each of nitrogen (N), P2O5, K2O and CaCO3 applied as seedbed fertilizers. Experiments 4 and 5 were similar in intent to Experiment 3, but treatments consisted of either nil or a very heavy application of the same fertilizer elements. In all experiments, the grass seed mixtures were sown in late summer after rotavation and burning of Cortaderia pilosa dominant indigenous vegetation on peaty soils. Percentage ground cover was estimated in the following spring and dry matter production through the first year was determined by sample harvests.

Initially, heavier seed rates resulted in higher percentage ground cover of sown species, but dry matter production over the season following sowing showed a significant increase only between the 25 and 35 kg ha−1 rates in Experiment 2. The modest levels of seedbed fertilizers applied in Experiment 3 had no significant effect on either percentage ground cover of sown species or dry matter production. Even at the higher levels used in Experiments 4 and 5, only N consistently increased dry matter yields, although a significant positive response was also obtained from CaCO3 in the final harvests.

The implications of the results to farmers in the Falkland Islands who may be contemplating reseeding are discussed.
The implications of controlling grazed sward height for the operation and productivity of upland sheep systems in the UK. 2. Effects of two annual stocking rates in combination with two levels of fertilizer nitrogen
Authors: SIBBALD A. R. , MAXWELL T. J. , MORGAN T. E. H. , JONES J. R. , REES M.E.
Published: April 2006

When grazed sward surface height was controlled within the range 3·75‐5·25 cm during spring and summer, the effects of two annual stocking rates of twenty (SR20) and twelve (SR12) Cheviot ewes per hectare with their lambs and two rates of nitrogen fertilizer, 100(N100) and 200(N200)kg Nha−1 per year on animal performance and yield of silage from areas of pasture surplus to grazing requirements were measured. Decision rules for management of sward height resulted in good control of swards and consistent and satisfactory individual animal performance across treatments. Total output of lamb was greater for SR20 than for SR12 (699 vs 424kg live weight ha−1; P < 0·001). Yield of silage was less for SR20 than for SR12 [27 vs 184 kg dry matter (DM) per ewe; P < 0·001] and less for N100 than for N200 (65 VS 146 kg DM per ewe; P < 0·01). Around the mating period, when sward height fell below 3·5cm, supplementary feed was offered. More concentrates were offered to the SR20 than to the SR12 ewes (12·3 vs 1·2kg DM per ewe; P < 0·001) and to the N100 than to the N200 ewes (8·3 vs 5·2kg DM per ewe; P < 0·01); trends in the amounts of hay offered during that period were similar.
The effects of phosphorus and form of nitrogen supply on leaf cell size and nutrient content in Trifolium repens and Lotus uliginosus
Authors: HART A. L. , COLLIER W. A.
Published: April 2006

White clover (Grasslands Huia) and lotus (Grasslands Maku) were grown in pots of soil at a range of phosphorus supply, and reliant on symbiotic nitrogen fixation (SN plants) or entirely on mineral nitrogen (MN plants). Shoots increased in weight with phosphorus supply. White clover MN shoots were bigger than those of SN plants except at the lowest level of phosphorus supply; lotus MN shoots were only bigger than SN shoots at the highest level of phosphorus supply. Leaf growth rate and size increased with phosphorus supply but were not significantly affected by the nitrogen treatments.

Estimates of cell size were made by determining DNA concentration, by digestion of tissue followed by counting and by taking vinyl impressions of epidermal cell surfaces. Lotus cells are bigger than those of white clover. ‘Digested’ cell sizes were not significantly affected by changes in phosphorus supply. Epidermal cell size increased with phosphorus supply, but the relationship was weaker in SN than in MN plants. Methods which give values for ‘average’ cell size are capable of detecting large‐scale differences, but methods able to resolve cell heterogeneity are necessary for an accurate picture of the relationship between leaf growth and cellular nutrition.

Average concentrations of total and inorganic phosphorus on a DNA basis did not differ between the species, contrary to concentrations on a dry weight basis, indicating that differences in phosphorus efficiency can be partly explained on the basis of average differences in cell size. Differences in inorganic phosphorous on a DNA basis at higher levels of supply suggested an additional intrinsic difference in cellular accumulation of inorganic phosphorus between the two species.