bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intake and digestion in swamp buffaloes and cattle. 4. Particle size and buoyancy in relation to voluntary intake
Authors: Kennedy P. M. 
Published: March 2009

SUMMARYThe buoyancy and distribution within the rumen of feed particles were measured to assess the extent to which particle buoyancy modulated the movement of particles within and from the reticulorumen. Two experiments conducted in north Queensland in 1988 involved swamp buffaloes (Bubalus bubalis)and crossbred cattle (Bos indicus × B. taurus) fed rice straw with various supplements of energy and protein, lablab (Lablab purpureus), verano (Stylosanthes hamata cv. verano) and two grasses, sorghum (Sorghum bicolor × S. sudanense) and pangola (Digitaria eriantha). Apparent passage rate of particles from the reticulorumen bore an inverse curvilinear relationship to particle size. Passage rate of the smallest particles, retained by a cloth of aperture 50 μm, was faster in buffaloes. Mean particle size of total rumen digesta was smaller in buffaloes than in cattle in Expt 1 with rice straw, but there was no difference between the forage diets offered in Expt 2. The large particle content in digesta (dry matter per kg) in the dorsal rumen was greater than that in the ventral rumen, which in turn was greater than that in the reticulum. The sedimentation rate of particles was measured by a procedure designed to interfere as little as possible with microbial fermentation. A curvilinear relationship was evident between sedimentation rate and particle size; the medium particles sedimented faster than the fine and large particles. Sedimentation rates of some particle fractions were greater in buffaloes than in cattle. Between diets there were marked differences in sedimentation rates of large particles, but these differences decreased with smaller particle size. Large particles from the dorsal sac sedimented faster than those from the ventral sac, and there was no obvious dorsal raft. There was no apparent relationship between particle buoyancy and ease of particle escape from the reticulorumen. The results are discussed in terms of current theories of the physical factors involved in the control of voluntary feed consumption by ruminants.
Hardseededness and pattern of hard seed breakdown in Sardinian populations of Medicago polymorpha under field conditions
Authors: Porqueddu C. , Loi A. , Cocks P. S. 
Published: March 2009

SUMMARYThe hardseededness and pattern of hard seed breakdown of 35 accessions of Medicago polymorpha, collected in Sardinia, were compared with Circle Valley, an Australian cultivar, near Sassari, northern Sardinia. The seed was produced in three consecutive years (1991–93), and the hardseededness measured at intervals in trie field during the summer following its production. The results were related to previously measured pod characteristics that separated the varieties polymorpha and vulgarisThe variety polymorpha, which had been collected mainly from coastal regions, was harder seeded than the variety vulgaris, which had been collected mainly from cooler, inland regions. Wherever the origin, hardseededness levels remained > 85% even in the year when seed softening was greatest (1992). In other years means of 94% (1991) and 97% (1993) of seed remained hard in late September. In 1992 and 1993 most hard seed breakdown occurred between early August and early September, while in 1991 hard seed breakdown occurred in September itself. There was little difference between varieties in the pattern of hard seed breakdown. Seedling emergence was related to the amount of seed that became soft during the previous summer. The results also confirmed that hard seeds soften sequentially from the proximal end of the pod (nearest the calyx) to the distal end.The Australian cultivar was one of the hardest seeded accessions, showing very little hard seed breakdown during the experimental period. This result highlights the importance of selecting pasture legumes under the conditions in which they are to be used: in Australia, cultivar Circle Valley usually loses some 20% of its hardseededness in the first year, comparable with the softest Sardinian accessions in Sardinia. Even among the Sardinian accessions, most were probably too hard seeded in 1993. Nevertheless it is likely that material in this experiment will be released as commercial cultivars for Sardinia and other similar environments in the Mediterranean basin.
Effect of interference between plots on yield performance in crop variety trials
Authors: Talbot M. , Milner A. D. , Nutkins M. A. E. , Law J. R. 
Published: March 2009

SUMMARYMethods are described for estimating interplot interference in variety trials. The effects on variety yield performance of interference from varieties in adjacent plots was studied for more than 600 UK National and Recommended List variety trials in the years 1987–1991. The crops examined were barley, wheat, oats, grain peas, beans, oilseed rape, forage maize and sugarbeet. Estimates of differences in variety performance may be biased by as much as 4% in some crops. Factors associated with interference included plant height, standing ability and disease susceptibility. An approach is outlined for limiting the effects of interference through controlled randomization within trials.
Five years of straw incorporation and its effect on growth, yield and nitrogen nutrition of sugarbeet (Beta vulgaris)
Authors: Allison M. F. , Hetschkun H. M. 
Published: March 2009

SUMMARYIn 1990–92, field experiments were performed at Broom's Barn Experimental Station to study the effect of 5 years' repeated straw incorporation on sugarbeet. Straw incorporation had no effect on plant population density. Processing quality was reduced by incorporated straw but N had a much larger effect. The effect of incorporated straw on the mineral N content of the soils and N uptake by beet was inconsistent, and this may be related to the amount of soil mineral N present when the straw was incorporated. The efficiency of fertilizer use was unaffected by straw incorporation. On Broom's Barn soils when straw was incorporated, the optimal economic N dressing was c. 120 kg N/ha, and in unincorporated plots it was c. 100 kg N/ha. At the optimal economic N rate, incorporated straw increased beet yields.
Rumen-undegradable dry matter and neutral detergent fibre as ratio indicators of digestibility in sheep given cereal straw-based diets
Authors: Fondevila M. , Castrillo C. , Gasa J. , Guada J. A. 
Published: March 2009

SUMMARYStudies were conducted in 1989 at the University of Zaragoza, Spain, to determine the value of undegradable dry matter and neutral detergent fibre (uDM and uNDF) forestimating apparent dry matter digestibility (DMD), with sheep diets based on untreated or ammonia-treated barley straw (US or TS) offered alone or supplemented with 300 or 600 g/day of grass hay (H), barley (B) or sugarbeet pulp (P). Marker recovery in faeces was 107·9±1·90 and 96·4±1.43% for uDM and uNDF, respectively. Faecal uDM excretion was overestimated, especially with TS as sole feed and in B-supplemented diets (116%), whereas underestimation of uNDF excretion was observed mainly in unsupplemented US (92%), supplemented TS (92%) and in diets including H (91 %). Digestibility estimations from uDM or uNDF concentration in feeds and faeces (DuDM or DuNDF) were affected in the same way as DMD by the dietary sources of variation. Correlation coefficients between in vivo digestibility and its estimates with both internal markers were 0·80, and differences between DMD and DuDM and DuNDF were –2·5±0·14 and 2·2±0·13 percentage units, respectively. The suitability of both markers for predicting apparent digestibility, and the choice between them, would depend on diet characteristics.
Forage yield and quality interactions between white clover and contrasting ryegrass varieties in grazed swards
Authors: Evans D. R. , Humphreys M. O. , Williams T. A. 
Published: March 2009

SUMMARYThe impact of white clover on seasonal yield and nutritive value traits in perennial ryegrass was investigated using six ryegrass varieties which expressed contrasting levels of water soluble carbohydrate (WSC). These were sown in an upland environment at Syfydrin, near Aberystwyth, in mixtures with white clover and in monocultures. Plots were grazed by sheep and sampled during 1991–93. Grass yields in mixtures and monocultures were similar except during mid to late summer when clover contents were high. White clover had a considerably lower WSC content but a much higher crude protein (CP) content than the ryegrasses. The WSC content of grasses in mixed swards was consistently lower than in monocultures and markedly so during mid to late summer. Use of ryegrass varieties with a relatively high WSC content can compensate for this depletion. Consequently high WSC grasses may reduce the amounts of nitrogen excreted by ruminants grazing mixed swards by increasing the efficiency of protein use from clover.
The role of wind and insects in cashew (Anacardium occidentale) pollination in NE Brazil
Authors: Freitas B. M. , Paxton R. J. 
Published: March 2009

SUMMARYThe pollination requirements of cashew (Anacardium occidentale L.), an andromonoecious tree, were studied in NE Brazil, where cashew is indigenous. It was shown through the use of bagging and caging experiments, controlled hand-pollination and emasculation of flowers, that the wind plays little role in cashew pollination and that cashew is self-fertile, although only pollen from the large stamen, either male or hermaphrodite-derived, can effect pollination. Insects appear to be the major pollinators of cashew, in agreement with the pollination syndrome suggested by the morphology of its flowers. Direct observations of insects visiting flowers and counts of pollen grains adhering to such insects suggest that the honey bee (Apis mellifera L.), although a non-native insect, is the major pollinator of commercially grown cashew in NE Brazil.
Effect of condensed tannins inLotus corniculatusupon lactation performance in ewes
Authors: Wang Y. , Douglas G. B. , Waghorn G. C. , Barry T. N. , Foote A. G. 
Published: March 2009

SUMMARYA grazing experiment was conducted for 8 weeks in the spring/summer of 1993 at Palmerston North, New Zealand, to study the effects of condensed tannins (CT) inLotus corniculatus(birdsfoot trefoil cv. Grasslands Goldie) upon the lactation performance of ewes rearing twin lambs. Effects of CT were evaluated by studying the responses of ewes to twice daily oral supplementation with polyethylene glycol (PEG; MW 3500), which binds and inactivates CT. A rotational grazing system with restricted feed allowance was used. Measurements were made of pre- and post-grazing herbage mass, the composition of the feed on offer and diet selected, voluntary feed intake (VF1), milk yield and composition, liveweight gain and wool production. The concentration of metabolites in rumen fluid and in blood plasma was also measured. Lotus contained 35–5 g total nitrogen and 44–5 g total CT/kg dry matter in the diet selected, with anin vitrodigestibility of 73%. At peak lactation (weeks 3 and 4) milk yield and composition were similar for control (CT-acting) and PEG-supplemented (CTinactivated) ewes but, as lactation progressed, the decline in milk production and in the secretion rates of protein and lactose were less for control than for PEG-supplemented ewes. In mid and late lactation (weeks 6–11), control ewes secreted more milk (21 %), more milk protein (14%) and more lactose (12%) than PEG-supplemented ewes. Milk fat percentage was lower for control than for PEG-supplemented ewes, but secretion rates of fat were similar for the two groups. VFI, liveweight gain and wool growth were similar for both groups. Plasma urea and glucose concentrations were lower for control than for PEG-supplemented ewes, but concentrations of non-esterified fatty acids (NEFA), growth hormone and insulin were similar for the two groups. The concentrations of ammonia and molar proportions ofiso-butyric,iso-andn-valeric acids in rumen fluid were lower for control than for PEG-supplemented ewes; molar proportions of acetic, propionic and H-butyric acids were similar for the two groups. It was concluded that for ewes rearing twin lambs grazingL. corniculatus, the action of CT increased milk yield and the secretion rates of protein and lactose without affecting VFI, thereby increasing the efficiency of milk production. The increased milk production did not appear to be mediated by effects on plasma concentrations of growth hormone or insulin.
Seed yield and hardseededness of two amphicarpic pasture legumes (Vicia sativa ssp. amphicarpa and Lathyrus ciliolatus) and two annual medics (Medicago rigidula and M. noeana)
Authors: Christiansen S. , Abd El Moneim A. M. , Cocks P. S. , Singh M. 
Published: March 2009

SUMMARYYields and hardseed breakdown of underground and aerial seeds in subterranean vetch (Vicia sativa ssp. amphicarpa) and lathyrus (Lathyrus ciliolatus) and aerial seeds of Medicago rigidula and M. noeana were compared at Tel Hadya, near Aleppo, in north Syria between 1990 and 1992. Underground and aerial seed and straw (mature herbage) yields were measured at maturity in the first spring, and hardseed breakdown over the following summer, autumn and winter. Regenerating herbage production was measured in the second spring.In the establishment year (292 mm rainfall) the medics produced twice as much straw as the amphicarpic species. In contrast, seed yields were less than half: M. rigidula and M. noeana produced 412 and 110 kg/ha respectively, while subterranean vetch and lathyrus produced 1174 and 736 kg/ha. More than 95 % of the total seed yield of the amphicarpic legumes was underground. Underground seeds of the amphicarpic legumes were larger than aerial seeds, and almost 10 times as large as the medic seeds.Seeds of all species were > 90% hard when newly set in summer. At the first seasonal rains > 95% of underground seed had softened, compared with 5 and 40% of the aerial seeds of vetch and lathyrus respectively. The medics remained > 90% hardseeded. In laboratory tests, embryo dormancy was observed in all species prior to the onset of first seasonal rains. For the amphicarpic legumes, but not for the medics, embryo dormancy persisted into winter. In the field, and after all germination events, 900–1430 seeds/m2 of subterranean vetch seed remained in the soil. This was considerably more than expected, based on the low levels of hardseededness and embryo dormancy observed in the laboratory. The results suggest that dormant seeds of the amphicarpic legumes need light to germinate.In the second year (353 mm rainfall), regenerating M. rigidula produced 5·3 t/ha compared with 3·4 t/ha by the best subterranean vetch from approximately equal numbers of seedlings. The amphicarpic legumes germinated later and over a more extended period than the medics, indicating that they could become weeds in a cereal/pasture rotation. However, the results suggest that in drier areas or in drier years the vetches will compare favourably with the medics in most respects. Clearly, subterranean vetch and lathyrus have great potential for pasture improvement in dry areas.
Response of sunflower (Helianthus annuus) to planting pattern and population density in a desert climate
Authors: Esechie H. A. , Elias S. , Rodriguez V. , Al-Asmi H. S. 
Published: March 2009

SUMMARYThe effects of three planting patterns (ridge, furrow and flat) and three population densities (31800, 47600 and 71400 plants/ha) on the growth and yield of three sunflower hybrids, Flamme, Upsolveraflor and Isostar, were investigated at the Sultan Qaboos University Experiment Station, 1990–93. Seed and oil yields were higher in the ridge-planted sunflower than those planted in furrow or flat patterns, the order being ridge > flat > furrow. However, the magnitude of yield differences between ridge-planted and flat-planted sunflower was not sufficiently high to compensate for the additional labour and materials required for making ridges. Based on this, planting in the flat was recommended. Although increased population density resulted in taller plants, lodging was generally low and did not constitute a serious problem. Biomass/plant, head weight, receptacle weight, head diameter, number of seeds/head and 1000-seed weight decreased with increase in plant population density. Flamme had its highest seed and oil yield at 71400 plants/ha, while Isostar attained its highest yield at 47600 plants/ha. Isostar outyielded the other two hybrids and appeared to have a potential for commercial production in a desert climate.
Effects of application technique and anaerobic digestion on gaseous nitrogen loss from animal slurry applied to ryegrass (Lolium perenne)
Authors: Rubæk G. H. , Henriksen K. , Petersen J. , Rasmussen B. , Sommer S. G. 
Published: March 2009

SUMMARYAmmonia volatilization and denitrification were measured in a ryegrass field in Denmark after direct injection and application with trail hoses of an untreated cattle slurry and an anaerobically digested slurry in late May-early June 1993 and 1994. Ammonia volatilization was measured using a windtunnel system for a period of 8 days after slurry application. Denitrification was measured for a period of 21 days after slurry application. In an adjacent field experiment, nitrogen-uptake (N-uptake) was determined in the first two cuts of the ryegrass harvested after slurry application. N losses through ammonia volatilization were larger in 1993 than in 1994 due to differences in climatic conditions. Ammonia volatilization was lowered substantially (47–72%), when slurry was injected compared with surface application. In 1993 the loss from surface-applied digested slurry was only 35% of total ammoniacal nitrogen (TAN), while the loss from the raw slurry was 47%. There were no significant differences in ammonia volatilization from the two slurry types in the other experiments. N losses through denitrification were low (< 2% of TAN), but there were clear differences in the losses, depending on slurry type, application method and experimental year. Injection of the slurry gave a larger N-uptake in the first cut of grass compared to the trail-hose application. In 1993 N-uptake from the digested slurry treatment gave significantly larger N-uptake compared to the raw slurry in the first cut.
Fertilizer nitrogen addition to winter wheat crops in England: comparison of farm practices with recommendations allowing for soil nitrogen supply
Authors: Wilson W. S. , Moore K. L. , Rochford A. D. , Vaidyanathan L. V. 
Published: March 2009

SUMMARYMeasurements were made during 1987/88 on 20 winter wheat crops grown in Essex, four on each of five soil types – sandy loam, sandy silt loam, silt loam, calcareous clay loam and clay loam – where winter wheat, dried peas, winter faba beans or winter oilseed rape was the previous crop in 1986/87. The sites had a wide range of soil mineral N (SNS), 40–198 kg/ha N, as NH4 plus NO3, in the 0–90 cm soil profile. Optimum grain yield and fertilizer N could not be estimated but yields measured in the absence of fertilizer N enabled evaluation of the use of SNS on its own and the response to fertilizer N (187 ± 32 kg/ha). For crops receiving fertilizer N, each tonne of grain was associated with 35kg of total available N in the soil profile (SNS + fertilizer N); a little over 63% of this N was found in the above-ground parts of the crops at harvest. Fertilizer N requirement was predicted as:Fertilizer N needed (kg/ha) = [35 × predicted grain yield (t/ha)]–SNS (kg/ha)An arbitrary assumption of 8 t/ha grain for every site (fortuitously the same as the average of 8·07t/ha measured in crops given fertilizer N) showed that differences between added and predicted amounts of N differed by c. 30 kg/ha for only seven of the 20 sites, mostly because of large SNS or yields much less than 8 t/ha. Measuring SNS and using the formula would be justified in the majority of winter wheat crops, provided reliable yield estimates could be made in time.
Residual effects of phosphorus applied to soyabean or wheat in a soyabean–wheat cropping system on a typic haplustert
Authors: Rao A. Subba , Reddy K. Sammi , Takkar P. N. 
Published: March 2009

SUMMARYDuring a 3-year experimental period (between 1992 and 1995), residual effects on yields of subsequent crops of phosphorus applied either to soyabean or wheat, and on recoveries of the added P and changes in the available P, were studied in a soyabean–wheat cropping system on a typic haplustert very low in available P at Bhopal, India. Phosphorus was applied at rates of 0–52 kg P ha-1 (five treatments) to soyabean and 0–39 kg P ha-1 (three treatments) to wheat during the first year, and in the subsequent years the residual effects were studied in relation to fresh applications of 39 kg P ha-1 to each crop. The yields of soyabean and wheat were increased significantly by the application of P to each crop. Phosphorus applied to soyabean showed residual effects in two succeeding crops, whereas P applied to wheat showed a residual effect in only one succeeding crop. Phosphorus applied to soyabean was more efficiently utilized by the succeeding crops compared to that applied to wheat in the rotation. The recoveries of added P were greater with smaller rates of added P and greater in the first two residual crops. Olsen P in soil was adequate only in the first year and it fell below the critical limit in the subsequent two cycles of cropping. Cumulative P uptake by crops determined the levels of available P in the soil and soil test values declined with increase in cumulative P uptake over time.
Effect of condensed tannins in Lotus corniculatus upon the digestion of methionine and cysteine in the small intestine of sheep
Authors: Wang Y. , Waghorn G. C. , McNabb W. C. , Barry T. N. , Hedley M. J. , Shelton I. D. 
Published: March 2009

SUMMARYAn experiment was conducted at Palmerston North, New Zealand, to determine the effect of condensed tannins (CT) on the true and apparent digestion of methionine and cysteine in the small intestine (SI) of sheep fed fresh Lotus comkulatus. The lotus contained c. 30 g total CT/kg dry matter (DM) and was fed hourly to sheep in metabolism crates. Four sheep were prepared with rumen and abomasal cannulae which enabled the indigestible liquid phase marker, chromium ethylene diamine tetra-acetic acid (Cr-EDTA), to be infused into the rumen to estimate digesta flow. True digestibility of plant methionine and cysteine in the SI and their site of absorption in the SI were determined from 35S-labelled L. corniculatus homogenate continuously infused into the abomasum. After 9 h infusion of the 35S-labelled lotus homogenate, the sheep were slaughtered and digesta samples were taken at intervals along the small and large intestines. The effect of CT was determined by comparing two control sheep (CT-acting) with two sheep given a continuous intraruminal infusion of polyethylene glycol (PEG, MW 3500) to bind and inactivate the CT.The CT reduced the true digestibility of plant methionine (0·72 v. 0·88) and cysteine (0·65 v. 0·81) in the SI relative to sheep receiving PEG. Condensed tannins also appeared to alter the site of digestion of both [35S]methionine and [35S]cysteine in the SI, and increased the flux of both amino acids in the mid and latter thirds of the SI. CT did not affect the apparent digestibility of total methionine (0·82 v. 0·84) in the SI but reduced the apparent digestibility of total cysteine from 0·77 to 0·66. In control sheep CT increased the abomasal flux (as a proportion of eaten) of total digesta methionine (0·88 v. 0·76) and total digesta cysteine (0·74 v. 0·62). The apparent absorption of total methionine (plant + microbial + endogenous) was increased by the action of CT (0·72 v. 0·63 g/g eaten) but was similar for total cysteine (0·49 v. 0·48 g/g eaten) in both groups. It was concluded that CT reduced the true digestibility of plant methionine and cysteine in the SI. However, it was calculated that the action of CT actually increased the total amounts (g/g eaten) of plant methionine and cysteine absorbed from the SI, due to its effect in increasing abomasal flux.