bluuebunny/crossref_metadata_2025_split huggingface dataset:
The performance of summer‐calving cows grazing perennial ryegrass swards
Authors: FISHER G. E. J. , DOWDESWELL A. M. 
Published: April 2006

AbstractThe objectives of this experiment were to study the effects of different grazing managements in spring on herbage intake and performance of summer‐calving dairy cows and to examine the effects of regrowth in early June on herbage intake and cow performance. Four spring‐grazing treatments were applied to predominantly perennial ryegrass swards: Control (C), sward grazed by cows to 6–8 cm sward surface height (SSH); CG16, sward grazed by cows to 3–4 cm SSH in May and allowed to regrow to a target SSH of 16cm in early June; CG8, sward grazed by cows to 3–4 cm SSH in May and allowed to regrow to 8cm in early June; and SG8, sward grazed by sheep to 2–3 cm SSH in May and allowed to regrow to 8 cm in early June, All swards were continuously stocked by summer‐calving (May and July) primiparous and multiparous cows from 16 June to 7 September, to a target SSH of 8–10cm.Spring treatments bad marked effects on herbage intakes and milk production. Estimated in July by n alkane analysis, the mean herbage intake ± s.e.d. of cows on each treatment were 1·8, 1·4, 1·4 and 3·0 ± 0·31 kg dry matter (DM) 100 kg live weight (LW)−1 d−1 (P < 0·01) for treatments C, CG16, CG8 and SG8 respectively. Measured in August, intakes were 1·8, 20, 2·1 and 2·4 ± O·33kg DM 100kg LW−1 d−1 respectively. Severe spring grazing led to increased milk yield and reduced milk fat content from summer‐calving cows fed 5·2 kg d−1 of a proprietary concentrate. Average milk yields for the eleven experimental cows on each treatment were 24·3, 23·4, 26·2 and 29·0 ± 1·20 kgd−1 (P < 0·01) for C, CG16, CG8 and SG8, and average milk fat contents were 45·4. 42·4, 43·9 and 40·9 ± 1·02gkg−1 (P<0·05) respectively.The results suggest that severe grazing of swards in early season could improve herbage intake and milk yield of summer‐calving cows in mid‐ and late season. The most favourable spring treatment in this respect was severe grazing by sheep. However, this advantage could be negated in midseason by lax grazing at that time.
The nitrogen value of anaerobically digested sewage sludge applied to grassland during winter
Authors: EDGAR K. F. , KLESSA D. A. , FRAME J. , HARKESS R. D. 
Published: April 2006

AbstractThe manurial value of liquid anaerobically digested sewage sludge (LAS), surface applied once at four different times during winter to contrasting swards, was assessed over each of three growing seasons by comparison with fertilizer N. Four nominal rates of N (0, 18, 36 and 54 kg ha−1) were used based on the inorganic N content of LAS. Herbage dry matter (DM) and N uptake responses were measured by cutting three times per year.Application of LAS in late winter compared with early winter led generally to greater N uptake and DM production. Herbage production response from LAS ranged from 5·4 to 30·1 kg DM kg−1 N; within this range, larger responses were obtained from a sown sward than from permanent pasture. The apparent efficiency of LAS compared with fertilizer N ranged from 0·41 to 0·88 (permanent pasture) and 0·20 to 0·77 (sown sward) but occasionally mean apparent efficiencies of over 1·0 occurred because fertilizer N was poorly recovered. There was no residual effect on annual N uptake from applying sludge. It is concluded LAS is a useful nitrogenous manure when applied to grassland in late winter/early spring but more research is needed to elucidate the importance of pathways of N losses following the surface application of LAS, and to quantify these losses.
Effect of rainfall and temperature on yield of Vicia sativa under rainfed Mediterranean conditions
Authors: PAPASTYLIANOU I. 
Published: April 2006

AbstractThe productivity of Vicia sativa grown in rotation with barley under rainfed Mediterranean conditions was examined at two locations over several years (eighteen location × year situations). Rainfall during the growing season ranged from 200 to 500 mm. Vetch relied on indigenous rhizobia for nodulation and N fixation while for phosphorus it was fertilized with 20kgPha−1. Harvesting took place at the beginning of pod formation. The dry matter (DM) yield reached 6·6t ha−1 and the N offtake 215 kg ha−1. The highest yields were obtained when rainfall exceeded the 350 mm level. The N concentration of the forage was not influenced by rainfall or by the productivity of the plants. Yield of DM was related to the number of days of ground frost in January but not in February and March. Monthly minimum and maximum temperature was not related to the DM yield. The combination of monthly rainfall and temperature explained over 95% of the variation in yield.
The effects of stocking rate in spring, and topping on sward characteristics and dairy cow performance in a poor grass growing season
Authors: FISHER G.E.J. , ROBERTS D.J. 
Published: April 2006

AbstractA comparison was made under continuous grazing between applying a high stocking rate in spring (H) to maintain the sward surface height (SSH) of a perennial ryegrass pasture at 5–6 cm and a low stocking rate (L) to maintain SSH at 10–12cm with mechanical topping in mid‐June. The experiment was carried out in the dry season of 1989 and a lack of rainfall markedly affected the treatments and consequently animals were offered supplementary concentrate and forage in July to compensate for reduced grass intake and low SSHs.Treatment H maintained the density of live grass tillers and live: dead tiller ratio in mid‐and late season, compared with the L treatment. The measured interval between defoliation of individual grass tillers was significantly less in the L pasture in samplings taken between 2 May and 29 August. January/February calving cows on the L pasture produced significantly more milk cow−1 with higher concentrations of protein and lactose, but less milk ha−1 compared with cows on the H sward. The results indicate that topping of a laxly grazed sward in drought conditions has no positive effects on sward characteristics or milk production.
Opportunities for reducing the environmental impact of dairy farming managements: a systems approach
Authors: JARVIS S. C. , WILKINS R. J. , PAIN B. F. 
Published: April 2006

AbstractDairy farming systems are important sources for the emission of a number of materials that include various forms of nitrogen (NO3−, N2O and NH3) with potential environmental impact. The present paper is a systems synthesis study and assesses the likely impact of changes in management on N flows and losses. These include tactical fertilizer adjustment, slurry injection, maize silage production and the use of white clover as an alternative to fertilizer N. Implications for greenhouse gases (N2O and CH4) and support energy have also been considered. Substantial reductions in inputs and total and proportional losses by all die options considered were predicted by this study. Thus, using a tactical approach to fertilizer application and injecting slurry or using 50% maize silage reduced overall N losses from 160 (under conventional management) to 86 and 109kg Nha−1 respectively. Combining both possibilities reduced losses further to 69 kg ha−1. Although use of white clover, especially at low contents in the sward, was the most effective regime to reduce losses, this was at some cost to production so that losses per livestock unit (LU) did not always differ from those under other managements. Changing the N management had consequences for greenhouse gas emission with an estimated maximum 70% reduction in N2O release. The effects on CH4 emissions were relatively small. Substantial reductions in support energy costs were also obtained: these arose mainly from the reduction in fertilizer N use, which represented 66% of the total support energy in the original system.
The effect of timing of slurry application on the microflora of grass, and changes occurring during silage fermentation
Authors: DAVIES D. R. , MERRY R. J. , BAKEWELL E. L. 
Published: April 2006

AbstractCattle slurry (50 m3 ha−1 equivalent to 68 kg N ha−1) was applied to grassland plots 70 d (early application) and 34 d (late application) before ensiling and the retention and survival of slurry and epiphytic micro‐organisms on the growing herbage were examined and compared with those on herbage from corresponding fertilizer‐treated plots. The populations of lactic acid bacteria, enterococci and enterobacteria on herbage increased dramatically after slurry application. Thereafter, numbers of lactic acid bacteria declined, although they were always higher than on untreated herbage. Number of enterobacteria also declined but were higher on chopped grasses at ensiling [106 colony‐forming units (CFU) g−1 fresh matter (FM)] than they were on hand‐cut. unchopped herbages at all previous sampling times. Clostridia numbers were lowest on untreated and highest on slurry‐treated herbage, particularly after the late application (>103 CFU g−1 FM). Herbage was harvested 70 d and 34 d after slurry application, chopped and ensiled in laboratory silos. All herbages, irrespective of treatment, had low dry matter (DM) values (ranging from 149 to 170 g kg−1 FM) and fairly low water‐soluble carbohydrate (WSC) concentrations (130 g kg−1 DM or less). The initial rate of pH decline up to 4 d was most rapid in slurry‐treated herbages, with all pH values falling to < 4. 5 by day 4 and remaining there until day 21. However, after 90 days the pH values of all silages had risen to > 4. 5. accompanied by a marked decline in lactic acid concentration. Lactic acid‐fermenting Clostridia increased in numbers, reaching peak values of 107 CFU g−1 FM by day 21, remaining high until opening, and were probably responsible for increases in butyric acid levels in all silages, with the highest concentrations occurring in those prepared from slurry‐treated herbages. The results suggest that, although some faecal lactic acid bacteria may have beneficial effects in the early stages of fermentation, Clostridia from slurry can survive on herbage for extended periods. The results indicate that the potential for growth of Clostridia in silage may be independent of source or size of the initial population even at tow pH, if other conditions are favourable.
Effects of interval between harvests and application of fertilizer N in spring on the growth of perennial ryegrass in a grass/white clover sward
Authors: WILMAN D. , FISHER A. 
Published: April 2006

AbstractA perennial ryegrass/white clover sward, which had been grazed for over 2 years, was cut at 1‐, 2‐, 3‐ or 6‐week intervals from 18 April to 28 November 1986. Two rates of fertilizer N application in spring, 0 and 66 kg N ha−1, were compared. Perennial ryegrass growth was studied in three 6‐week periods, beginning on 18 April, 18 July and 17 October. Clover growth was studied in the same three periods and described by Fisher and Wilman (1995) Grass and Forage Science, 50, 162–171.Applied N increased the number of ryegrass tillers m−2, the rate of leaf extension and the weight of new leaf produced tiller−1 and m−2per week. Increasing the interval between cuts reduced the number of ryegrass tillers m−2 and increased the rate of leaf extension, weight tiller−1and the weight of new leaf produced tiller−1week−1. Increasing the interval between cuts increased the weight of new ryegrass leaf produced m−2 where N had recently been applied, but otherwise had little effect on the weight of new leaf produced m−2. Applying N favoured the grass in competition with the clover in every respect, whereas increasing the interval between cuts only favoured the grass, compared with clover, where N had recently been applied; where N had not been applied, the ratio of ryegrass tillers to clover growing points in the sward was very little affected by the interval between cuts.
Use of bovine somatotropin for milk production: the effect of time of treatment initiation on milk production of Holstein/Friesian dairy cows placed on a high‐forage, low‐concentrate feeding system
Authors: PHIPPS R. H. , ADRIAENS F. , HARD D. L. , DE KERCHOVE G. , WELLER R. F. 
Published: April 2006

AbstractSixty multiparous Holstein/Friesian cows were used in a 2 × 2 factorial design trial to determine the effect of the administration of bovine somatotropin (BST), at either 60 or 120 ± 3 d post partum, on milk production. All cows were offered ad libitum a forage mixture containing, on a dry‐mailer (DM) basis, grass and maize silage in a 1:1 ratio and 4 kg d−1 fresh weight of concentrate, which contained 115 and 495 g kg−1 DM of neutral detergent fibre (NDF) and crude protein (CP), respectively, and 13–5 MJ kg−1 DM metabolizable energy (ME). BST‐treated cows received subcutaneous injections of a prolonged‐release formulation of BST (sometribove). Injections were administered into the ischiorectal fossa at 14‐d intervals for the remainder of the lactation. This schedule resulted in sixteen and twelve injections cow−1 when treatment w as in it rate d at 60 and 120 + 3 d post partum respectively. This corresponded to treatment periods of 32 and 24 weeks, in which the production responses were measured. When compared with control cows, the administration of BST from 60 and 120 ± 3 d post partum increased mean milk yield by 1–2 and 3.3 kg day−1 respectively, although only the latter milk‐yield response was significant (P <0.001). The administration of BST produced a small nonsignificant increase in DM intake, no effect on milk composition and a small but significant reduction in body condition In conclusion a significant milk‐yield response can be obtained from the use of BST in high‐forage, low‐concentrate feeding systems if forage quality is high and treatment initiation is delayed until mid‐lactation. This is illustrated by the fact that the lactation yield increased from 6054 to 6842 kg. and was obtained when using only 1.2 t of concentrate.
The use of repeated‐measurements analysis to describe the overwintering of white clover cultivars
Authors: COLLINS R. P. , FOTHERGILL M. , POTTER J. F. , RHODES I. 
Published: April 2006

AbstractAn experiment was set up to investigate the morphological and physiological changes occurring in two white clover (Trifolium repens) (clover) varieties, AberHerald and Huia, growing in binary mixture with two perennial ryegrass (Lolium perenne) (grass) varieties, Preference and Ba 10761. Measurements were made on four occasions during winter/spring 1993–94. The statistical procedure of antedependence analysis was used to check for the existence of serial correlations among data from the different sampling dates. Evidence of antedependence was found in only three of the seventeen variables measured, and an order of antedependence for each of these was estimated. The antedependence structure providing the best fit to the data was then used in an analysis of covariance on the data set for that variable. The rest of the seventeen variables could be safely analysed by a split‐plot analysis of variance for each sampling date separately. This result validated the sampling protocol used in the experiment.
The effects of sward characteristics and supplement type on the herbage intake and milk production of summer‐calving cows
Authors: FISHER G. E. J. , DOWDESWELL A. M. , PERROTT G. 
Published: April 2006

AbstractHigh (H; 27 350 m−1:) or low (L. 13 300 m‐1) tiller density perennial ryegrass swards were created in the mid‐ and late grazing season by imposing different sward heights in the spring. Summer‐calving cows then grazed these swards from 6 June to 2 September 1992 and were offered 5 kg fresh weight hd−1 d−1 of either a barley (S) or a molassed sugar beet pulp (F) based supplement. The factorial combination of sward and supplement types resulted in four experimental swards being grazed by thirteen Holstein/Friesian cows each.Supplement F contained more crude fibre (110 vs. 58 g kg−1) and less metabolizable energy [12–5 vs. 13–2 MJ kg−1 dry matter (DM)] than supplement S. Herbage on the H sward contained more metabolizable energy (11–9 vs. 104 MJ kg−1 DM) and crude protein (232 vs. 205 g kg−1 DM), had fewer rejected areas f 16–5 vs. 26–9%) and a higher live‐dead tiller ratio (4–6 vs. 2–1) than that on the L sward.Sward, but not supplement type, significantly affected the intake of grazed herbage (P<0–001). On average, the herbage intakes of cows grazing II swards were higher than for L swards (14–5 vs. 11 6kg DM d−1) and those of cows on the S and F supplements were 12–6 and 13–5 kg DM d−1 respectively. Averaged over the grazing period, sward and supplement had no significant effects on milk yield, milk composition or yield of constituents. When expressed on an average weekly basis, cows grazing an L sward and offered the F supplement on occasions had significantly lower milk yields and higher milk fat contents (P<005) than those grazing an H sward and offered the S supplement. There were no significant effects on cow live weight or condition score change. The results suggested that grazing swards with a high density of live tillers increased herbage intakes and on occasions milk yield, relative to low density swards. However, small increases in energy intake from sward and supplement effects were used primarily to ameliorate liveweight loss.
The effect of age of the sward on the relationship between water‐soluble carbohydrate accumulation and drought survival in two contrasted populations of cocksfoot (Dactylis glomerata L.)
Authors: VOLAIRE F. , GANDOIN J. M. 
Published: April 2006

AbstractIn Mediterranean drylands, drought survival is a major factor of persistence of perennial forage grasses. In the island of Corsica, plant survival and changes in water‐soluble carbohydrate (WSC) content were investigated in first‐ and second‐year swards of two populations of cocksfoot: Lutetia, a drought‐sensitive cultivar, and KM2, a drought‐resistant Mediterranean population. When subjected to a moderate drought under a rain‐shelter. Lutetia died whereas KM2 recovered with low mortality. The sensitivity of survival to the date of defoliation is emphasized. In first‐year swards, WSC content in entire tiller bases at the end of the drought was four times greater in KM2 than in Lutetia and was correlated with differential recovery in the two populations. Conversely in second‐year swards, no relationship between WSC content in entire tiller bases and recovery was found. However, WSC content in the youngest living enclosed leaves of KM2 accumulated to reach 63% of dry matter (DM) whereas in Lutetia WSC fell below 30% of DM; this factor might be associated with its survival. In both tiller bases and enclosed leaves, sucrose content and the content of large fructans tended to increase over the summer, whereas monosaccharide content declined. Enclosed leaves are the main survival organs: their role as a sink for translocated material (sucrose) and as a site of fructan accumulation is discussed.
Grass silage as a basic feed for store lambs. 3. Effect of barley supplementation of silages varying in chop length on silage intake and lamb performance
Authors: FITZGERALD J. J. 
Published: April 2006

AbstractAn experiment was carried out to study the effect of silage chop length and barley supplementation on silage intake and the performance of store lambs. The silages were cut from a perennial ryegrass regrowth at a relatively mature stage of growth in early July. Different types of harvester were used to produce a long silage (L), single‐chopped (S), double‐chopped (D), medium precision‐chopped (MP) or a short precision‐chopped (SP) silage. The chop length of the silages averaged 37.4, 12.4, 8.4, 7.0 and 2.9 cm respectively. All silages were treated with formic acid at 2.51 t−1grass. They were well preserved and of a good quality with a dry‐matter (DM) digestibility of 720–760 g kg−1 DM. The silages were fed ad libitum to Suffolk crossbred store lambs over a period of 10 weeks. Each silage was fed either alone or was supplemented with whole barley at 400 g lamb−1 d−1.When offered silage alone, intakes were 738, 679, 773, 980 and 910 (± 30) g DM d−1 for silages L, S, D, MP and SP respectively. Similar relative differences in intakes between the silages were evident when supplemented with barley. Liveweight gain on silage alone was higher on the precision‐chopped silages (85–93 g d−1) than the long or flail‐chopped silages (28–49 g d−1). Liveweight gain on the precision‐chopped silages was also better when supplemented with barley (150 vs. 90–112 (± 90) g d−1). Silage intake and lamb performance were similar for the MP and SP silages, despite the difference in chop length.Barley supplementation reduced silage intake to a similar extent for all silages (‐9%) and increased total DM intake (+ 30%) and metabolizable energy intake (+ 37%). The substitution rates of silage for barley were similar for all silages and averaged 0.24 g silage DM g−l barley DM. The response in weight gain per 100g of barley fed was similar for all silages and averaged 20.0 g liveweight gain and 13.4 g carcass gain. Feed conversion efficiency of the total diet was similar for the Mail‐chopped and precision‐chopped silages but was less for the long silage.The results of this study show that the benefit in weight gain due to the higher intake of precision‐chopped silage was maintained when the silage was supplemented with a moderate level of barley. Such silage required supplementation with barley (400 g d−l) to achieve a rate of liveweight gain of 150g d−1.
Response of perennial ryegrass varieties to annual changes in sward management
Authors: GILLILAND T. J. 
Published: April 2006

AbstractThe effect of annually switching sward management between cutting regimes that simulated rotational grazing and those for forage conservation vs. maintaining a constant management regime was studied by testing for ranking‐order changes between six perennial ryegrass varieties.Total dry‐matter (DM) yields were found to change in response to an annual switch in management. When under a conservation management and switched in the next year to simulated grazing, all six varieties yielded more in that year than when they were maintained constantly under simulated grazing. Similarly, when under a simulated grazing management and switched in the next year to conservation, all six varieties yielded less than when maintained constantly under a conservation management. These yield differences were largely expressed in spring of the year following the management switch.Differences in the ranking order of varieties were observed between the constant sward management treatments and the alternating managements. However, in these changes in variety ranking, no variety was consistently favoured or disadvartaged by the annual switch in management. Therefore, no clear evidence was produced that an alternating management system had any consistent effect on variety ranking and the observed changes were possibly due to the normal year‐to‐year variation frequently recorded in variety performance trials.