bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating digestibility and faecal output in lambs using internal and external markers
Authors: Krysl L. J. , Galyean M. L. , Estell R. E. , Sowell B. F. 
Published: March 2009

SummaryTwenty fine-wool, ruminally cannulated lambs (average weight 45–9 kg) were used in a completely random design to evaluate the ability of three internal markers to predict dry matter digestibility and two external markers to estimate faecal output. Lambs were allotted randomly to one of four diets: 100% prairie hay (PH), 100% lucerne hay (LH), 50% prairie hay:50% sorghum grain (PS) and 50% lucerne hay: 50% sorghum grain (LS). The trial consisted of a 14-day adaptation period followed by a 7-day total faecal collection period. Feed and faecal samples were subjected to 96 h ruminal fluid and 48 h acid-pepsin digestions, followed by extraction with acid detergent (IVADF) or neutral detergent (IVNDF) solution. Dry matter digestibility (DMD) calculated from feed:faeces ratios of IVADF, IVNDF and acid detergent lignin (ADL) was compared with in vivoapparent digestibility. Ytterbium-labelled forage (YLF) and dysprosium-labelled faeces (DLF) were pulse-dosed via ruminal cannulae, and faecal Yb and Dy excretion curves were fitted to a one-compartment, agedependent model for estimation of faecal output, paniculate passage rate (PPR) and mean gastrointestinal retention time. In vivoDMD in lambs fed PH was greater (P <005) than DMD calculated from IVNDF, IVADF and ADL. In lambs fed LH and LS, in vivoDMD did not differ (P >005) from marker estimates. In vivoDMD for lambs fed PS did not differ from IVNDF or IVADF estimates but was greater than (P <005) the ADL estimate. No differences (P> 005) were observed in recovery among the three internal markers for any of the diets. Faecal output for lambs fed PH did not differ {P >005) from marker estimates but was overestimated by 15 to 20% by YLF and DLF. Faecal output for lambs fed LH was similar to the estimate from YLF, but less than (P <0–05) the estimate with DLF. For lambs fed PS, faecal output did not differ from marker estimates, but YLF and DLF values were 16% lower and 17% higher, respectively. No significant differences were observed in actual and estimated faecal output for lambs fed the LS diet. Estimates of PPR with DLF were numerically greater than YLF estimates for all diets except LS. Correspondingly, mean gastrointestinal retention time was less (P <005) for DLF compared with YLF for all diets except LS.
Voluntary intake and digestion of gorse (Ulex europaeus) by goats and sheep
Authors: Howe J. C. , Barry T. N. , Popay A. I. 
Published: March 2009

SummaryGorse (Ulex europaeus) was harvested in late spring, summer, autumn and winter and fed to six goats kept individually in metabolism cages for 21-day periods. The same gorse was also fed to sheep during the first two periods, but not in autumn and winter, as the hardness and sharpness of the needles caused total rejection by the sheep at these times. Measurements of voluntary intake and apparent digestibility were made over the last 7 days of each period. To minimize effect of diet selection the animals were fed at hourly intervals. Dietary lignin concentration was very high, ranging from 170 to 200g/kg D.M. Voluntary metabolizable energy (ME) intake for goats was respectively 1·60, 0·82, 0·72 and 0·41 times maintenance for the four harvesting times, late spring, summer, autumn and winter. Corresponding values for sheep were 0·90 and 0·33 for gorse harvested in late spring and summer. Thus, in late spring and summer, voluntary ME intake by goats was respectively 1·8 and 2·5 times that of sheep. The reduction in ME intake with time was attributed to increases in the contents of D.M. and of lignin + hemicellulose in depressing voluntary D.M. intake and apparent digestibility respectively. Voluntary intake of both supplementary water and total water per unit D.M. intake were consistently less for goats than sheep. From a comparison with published values, it was concluded that the superiority of. goats over temperate breeds of sheep in digestible dry matter intake (DDMI)/kg W0·75per day increased as the lignin content of the diet exceeded 120 g/kg D.M., indicating that goats must possess some superior mechanism for breaking down highly lignified diets such as gorse and willow. It is proposed that cashmere fibre production from goats grazing gorse for a 7-month period of each year should be evaluated as an alternative to regulating gorse with chemicals.
Changes with time of crop yields in a long-term experiment
Authors: Dyke G. V. 
Published: March 2009

SummaryYields of the three ‘test’ crops, winter wheat, potatoes, spring barley in the Rothamsted Ley–Arable experiments 1949–69 increased by about 100%, 80%, 40% respectively, each in a period of 19 years. The wheat variety was changed once during the period and this change is enough to explain most of he increase of yield. For potatoes there was no change of variety; the estimated effects of changes in manuring, etc. explain less than one third of the observed increase. For barley two changes of variety explain about one third of the increase; most of the remainder may be explained by improved manuring of preceding crops, especially potatoes. After 1969 the cropping was drastically changed but a few recent yields from other experiments at Rothamsted indicate that the steady rates of increase may have continued at least up to 1980.
Effects of different herbicides on theAzollaand blue—green algal biofertilization of rice
Authors: Singh A. L. , Singh P. K. , Singh P. L. 
Published: March 2009

SummaryPre-emergence herbicides applied at field recommended doses, 3 days after transplanting (DAT) rice plants, inhibited growth and N2-fixation ofAzolla pinnata(Bangkok) and BGA (blue-green algae) inoculated 10 DAT. This inhibition was up to 15 DAT inAzollaand up to 20 DAT in BGA. Butachlor and Oxadiazon resulted in higher toxicity toAzollaand BGA than Benthiocarb and Pendimethalin. The application of 0·5 kg/ha active ingredient of 2,4-DNa did not inhibit growth ofAzollabut inhibited BGA growth. However, 2,4-DEE, a post-emergence herbicide, applied 30 DAT showed inhibitory effects on the growth and N2-fixation of bothAzollaand BGA. Inoculation of 2·0 t/ha of freshAzolla10 DAT produced maximum biomass within 20–25 days of herbicide treatments, depending upon the season. The inoculation of 10 kg/ha of a dry mixture of BGA 10 DAT could produce the maximum biomass 60 and 80 DAT in control and herbicide treated plots, respectively. The biomass and nitrogen produced byAzollarecorded at maximum mat formation were similar in both herbicide treated and untreated plots, but in BGA these were higher in controls than those of herbicide treated plots.The useof Azollaand BGA biofertilizers along with herbicides increased the grain and straw yields, and panicle number and nitrogen uptake, by rice over noAzollaor BGA treatments. TheAzollaand BGA treatments even without weeding increased rice yield up to that of herbicide and biofertilizer treatments.
A respiration chamber for the study of energy utilization for maintenance and production in the laying hen
Authors: Waring J. J. , Brown W. O. 
Published: March 2009

1. Construction and details of operation of a respiration chamber suitable for studies on the laying hen are described.2. Calorimetric data on the utilization of food energy from balanced rations and from glucose are given.3. The net energy of balanced rations for maintenance and production is 83·7% of the metabolizable energy. The figure for glucose is considerably higher.4. The maintenance requirement of the 2 kg. laying hen is 88·9 kcal. metabolizable energy/kg./day.5. Some comments are given on the significance of protein metabolism in relation to the use of indirect calorimetry for avian species.
Techniques for assessing the cold resistance of cereals in the selection of hybrid material
Authors: Bingham J. , Jenkins G. 
Published: March 2009

1. Data are presented to show that, in the United Kingdom, soil temperatures do not fall more than a few degrees below freezing point even during prolonged spells of abnormally cold weather.2. Two methods of assessing cold resistance in cereals are described in which the natural gradient between air and soil temperature is maintained. These involve the use of seed boxes 6 in. deep in one case and a portable field freezing cabinet in the other.
Effects of planting density and plant arrangement pattern on growth and yields of maize (Zea mays L.) and soya bean (Glycine max (L.) Merr.) grown in mixtures
Authors: Yunusa I. A. M. 
Published: March 2009

SummaryThe growth and development of maize and soya bean when grown in mixtures in different proportions and arrangements were studied at Samaru (11° 11' N, 38° E) and Yandev (07° 23' N, 09° 10' E) in the savannah belts of Nigeria. The crops were sown in both pure and mixed stands. The pure-stand densities were 513 plants/m2 for maize and 20·15 plants/m2 for soya bean. Mixtures were made in three proportions: additive (100:100), containing 100% of the sole crop population of each crop; semi-additive (67:67), containing 67% of each crop's sole population; and replacement (67:33 and 33:67), containing 67% of one crop's population to the other's 33%. The mixtures were formed either on the same ridge (in-ridge) or on different ridges (alternate ridge).Maize grain yield at Samuru was not significantly reduced in mixtures except where its proportion was reduced to 33% of its sole crop density. Seed yields in soya bean were significantly reduced in all mixtures, and when associated with maize density of not greater than 67%, soya bean was capable of 50% of its sole crop yield. At Yandev, late planting coupled with inadequate rainfall in the month following planting depressed seed yields in both crops, the sole crop yields being only 1·53 t/ha in maize and 0·24 t/ha in soya bean. Also maize appeared to be adversely affected in the mixtures at this location, the yields being significantly reduced in the mixtures irrespective of planting ratios.All mixtures, except 100:100 at Yandev, proved beneficial by producing land equivalent ratio (LER) values greater than one, while 67:67 proportions made higher gross returns than any of the sole crops at Samaru. In this experiment moderately high populations of each crop were found to be necessary to obtain beneficial yields from the mixtures. In this regard semi-additive mixtures, with 67% of each crop's pure stand population, appeared most appropriate.Incidence of maize streak was significantly lower in alternate ridge mixtures; otherwise the crop in the mixtures seemed to be little affected by pattern of plant arrangement; while soya bean was quite sensitive, its flowering and podding being significantly delayed in in-ridge mixtures at Yandev. The legume yields in this mixture were also slightly, though not significantly, adversely affected. Thus alternate ridge arrangement was more favourable.
Conserving and developing minority British breeds of sheep: the example of the Southdown
Authors: Hall S. J. G. 
Published: March 2009

SummaryThe Southdown is a terminal sire breed producing about 205 registered rams for commercial use in Britain each year. It is strongly associated with its native area of Sussex, with an hierarchical breed structure very similar to that of 30 years ago. The number of breeding ewes has declined from 5475 in 1957 to (minimum estimate) 1202 in 1985.French and New Zealand imports in the last 20 years have resulted in present-day British Southdown breeding rams being, on average, only 76% of British descent. If further importations are to be made, semen from rams without foreign blood should be taken for storage first, in the interests of genetic conservation.The required production of Southdown rams for commercial purposes is achieved with a rather small population size. It would be misleading to describe the Southdown as a ‘rare breed’ without taking account of its commercial function and breed structure.
Veno-arterial differences of immunoreactive and biologically active luteinizing hormone across the head in the cow
Authors: van Aarde R. J. , Heap R. B. , Hamon M. , Fleet I. R. 
Published: March 2009

SUMMARYImmunoreactive (I) and biologically active (B) luteinizing hormone (LH) was measured in jugular vein and carotid arterial plasma of four cows 110–140 min after luteinizing hormone releasing hormone (LHRH) injection. Plasma was separated on Ultragel AcA54 and fractions corresponding to those containing authentic bovine luteinizing hormone (bLH) were assayed. Immunoreactivity in venous or arterial plasma occurred mostly in fractions corresponding in molecular weight to bLH. Low activity was measured in several other fractions. Biological activity was also high in the same fractions from venous plasma, though it was not so pronounced in arterial plasma.A veno-arterial difference across the head for immunoreactive LH was found in all animals, and there was a significant difference in biologically active LH (mouse Leydig cell assay). The mean B:I value for immunoreactive LH was similar in venous and arterial plasma for three out of four animals, 0·72 and 0·66, respectively. In a fourth cow with a clinical history of infertility, the B:I value was low in both venous and arterial plasma, 0·19 and 0·08, respectively. The results indicate that infertility in this latter instance was associated with LHRH-induced secretion of a compound similar in molecular size and immunoreactivity to LH but deficient in biological potency.
Voluntary intake and digestion of ryegrass straw by llama × guanaco crossbreds and sheep
Authors: Warmington B. G. , Wilson G. F. , Barry T. N. 
Published: March 2009

SUMMARYThe voluntary feed and water intakes of five llama × guanaco crossbreds (New World camelids) and five sheep, and their abilities to digest various feed components and to utilize nitrogen, were compared using a diet of threshed ryegrass straw in New Zealand in 1987.The camelids ate more than the sheep, but intakes were similar relative to metabolic live weight (mean 37·6 g dry matter/kg W0·75 per day). They drank 0·62 times as much water as sheep per kg W0·75, and 0·57 times as much per g DM intake (P < 0·05). Mean apparent digestibilities of dry matter (47.7%), energy (41·6%) and cell-wall fractions (48·4%) were similar in both species, in spite of the sheep selecting a higher-N component of the diet. Variation in digestibility (e.g. organic matter digestibility) among individual sheep was inversely associated with the percentage of cell-wall constituents consumed. The faeces of camelids contained a significantly higher proportion of particles longer than 0·5mm than those of the sheep (17 v. 11% total DM), indicating a slightly larger threshold to passage from the forestomachs in the camelids.All animals were in negative N balance during the trial, but net loss of N was less in the camelids than in the sheep (27·6 and 49·5 g N/100 g N intake, respectively; P < 0·05), because of lower urinary N excretion (36·5 and 60·3 g N/100 g N intake, respectively; P < 0·05) of the camelids. The results suggest that camelids may be better suited than ruminants for production from poor-quality feeds, especially if water supply is limited.
Selection criteria in grass breeding. V. Performance of Lolium perenne genotypes grown at different nitrogen levels and spacings
Authors: Lazenby Alec , Rogers H. H. 
Published: March 2009

1. The yields and yield components are recorded for selected clones of Lolium perenne, grown at different levels of applied nitrogen (0, 200, 400, 600 and 800 lb. of nitrogen per acre per annum) and at two spacings (widely spaced plants and simulated monoculture swards). Four harvests were taken in each of the two years 1962 and 1963.2. In both years there were significant and consistent differences between clones in their drymatter production per unit area, detectable at both spacings. A genotype x spacing interaction was detected only in 1962. A genotype x nitrogen interaction at some harvests was not found on annual totals.
Release of non-exchangeable potassium from some Rhodesian soils cropped with grass
Authors: Salmon R. C. 
Published: March 2009

1. Thirty Rhodesian soils were cropped with weeping love-grass (Eragrostis curvula) for up to 11 months in the glasshouse, the potassium released on cropping being compared with soil contents and that released on prolonged suspension in dilute CaCl2 or by reaction with H-exchange resin.2. Love-grass produced up to 33 tons of dry matter and removed up to 700 lb. of K2O/acre, and releases of non-exchangeable potassium ranged from 3 to 2931b. K2O/acre. With some soils potassium uptake by love-grass (and K-release) was about 60% of that reported for perennial rye-grass, showing that different crops have differing abilities to use non-exchangeable potassium reserves.
Yield response of barley to rainfall and temperature in Mediterranean environments
Authors: Van Oosterom E. J. , Ceccarelli S. , Peacock J. M. 
Published: March 2009

SUMMARYGrain yield of barley (Hordeum vulgareL.) in northern Syria is limited by water stress and extremes of temperature. The present study compared the grain yield of two barley cultivars, Harmal (spring type, cold-sensitive, early heading) and Arabi Aswad (winter type, cold-tolerant, medium early heading), under varying rainfall and temperature. Grain yield was obtained from three sites in northern Syria for seven seasons (1984/85 to 1990/91), resulting in 18 site × season combinations, here called environments. Multiple regression models, containing one rainfall and one temperature variable, were used to quantify yield responses to environmental fluctuations.Total seasonal rainfall was the variable most strongly correlated with the grain yield of Harmal, accounting for 62·8% of the variance. For Arabi Aswad, rainfall from November to January gave the best fit, accounting for 61·8% of the variance. December and January rainfall had the highest contribution to the yield of both cultivars; the contribution of March rainfall tended to be negative. The overall yield response to seasonal rainfall was 11·89 kg/ha/mm for Harmal and 8·57 kg/ha/mm for Arabi Aswad; the expected grain yield at the driest site wasc.1270 kg/ha for both cultivars. The addition of a temperature variable gave a better fit, accounting forc.80% of the variance in grain yield for both cultivars if winter rainfall was combined with number of night frosts in spring. It reduced the expected yields at the driest site toc.986 kg/ha. Arabi Aswad had a lesser response to both rainfall and frost than Harmal.In environments where low yields are due to both water and temperature stress, farmers are advised to grow Arabi Aswad because its lesser sensitivity to environmental fluctuations will ensure a better yield stability.
Effects of dietary phosphorus and nitrogen deficiencies on the intake, growth and metabolism of lambs
Authors: Ternouth J. H. , McLachlan B. P. , Clarke J. M. , Thomas B. J. 
Published: March 2009

SUMMARYThe effects of dietary deficiencies of phosphorus (P) and nitrogen (N) were studied in 28 lambs allotted to seven treatments for 18 weeks. The lambs in four treatments were offered roughage-based dietsad libitumcontaining high (H) or low (L) levels of P (4·13 or 0·98 g/kg dry matter (DM)) and N (108 or 68 g crude protein/kg DM). The lambs in the remaining three treatments were fed the same quantities of DM of the HNHP diet as the lambs receiving the three deficient diets (HNLP, LNHP and LNLP). A dietary deficiency of P caused a reduced DM intake and liveweight gain, lower yields of N and DM in carcass muscle and reduced DM, N and P contents of bone. A dietary deficiency of N resulted in reductions in DM intake, liveweight gain, DM digestibility, N balance, and in carcass muscle and bone DM and N. The deficiencies of N and P were not additive in lowering food intake but were additive in reducing the mineralization of the bones. The DM intake of the lambs offered their dietsad libitumwas closely correlated to the log of the plasma inorganic P and urea N concentrations (R =0·72). Feeding lambs with restricted quantities of diet HNHP resulted in higher liveweight gains and DM and N digestibilities than when any of the deficient diets were offered. Measurement of the N content of the lambs by a neutron capture gamma ray analysis technique showed that the changes were occurring progressively over the experimental period. The P content of the metatarsal bone, measured by a neutron activation technique, showed progressive changes. Although the faecal endogenous losses of P were related to P intake, high urinary losses were observed in those lambs which had their food intake limited by low dietary N alone, or had their food intakes restricted. The total endogenous P losses of the lambs were most closely dependent upon the DM intake and plasma inorganic P together. The efficiency of P absorption was high (> 0·75) in all lambs except for those given the HNHP dietad libitum. The glucose entry rate was reduced in the lambs offered diets deficient in either N or P. Mechanisms by which the N and P deficiencies reduce DM intake are discussed.
Effects of aldicarb, benomyl, dazomet, permethrin, pirimicarb, phorate and nitrogen fertilizer on maize (Zea mays) grown for 14 consecutive years on the same site
Authors: Barnard A. J. , McEwen J. , Hornby D. , Beane J. 
Published: March 2009

SummaryMaize was grown on the same Clay-with-Flints site at Rothamsted for 14 years (1974–87) in an experiment which tested cumulatively all combinations of three rates of N fertilizer (50, 100 and 150 kg N/ha) and six agrochemical treatments (aldicarb, benomyl, dazomet, phorate, benomyl + dazomet + phorate and none). Permethrin and pirimicarb were also tested in 3 of the years. The crop was grown for forage from 1975 to 1987 and for grain from 1974 to 1976. With 150 kg N/ha, the average forage yield was 10·5 t dry matter/ha and there was no overall decline during the experiment; annual yields ranged from 5·9 to 14·5 t/ha. From 1975 to 1983, yields were on average 0·2 t/ha less with 100 kg N/ha and 1·0 t/ha less with only 50 kg N/ha than with 150 kg N/ha. The crop grown for grain in 1974 failed but in 1975 it gave 3·5, 3·6 and 3·8 t/ha with 50, 100 and 150 kg N/ha, respectively, and 3·3 t/ha in 1976 with all N rates. The cultivars grown, Cargill Primeur 170, Caldera 535 and Fronica, matured too late to ensure a grain harvest at Rothamsted.Pests observed on the crop included nematodes of the genera Pratylenchus, Tylenchorhynchus and Tylenchus/Ditylenchus and initially some Heterodera avenae, the aphids Metopolophium dirhodum and Sitobion avenae, and frit fly (Oscinella frit). Common smut (Ustilago maydis) was the only fungus disease recorded and Microdochium bolleyi, possibly a minor pathogen, occurred on roots. There was no overall increase in the incidence of pests and pathogens during the experiment. Agrochemical treatments increased yields in all years; the most effective was the combined treatment with benomyl + dazomet + phorate which gave on average 1·4 t/ha more forage than the untreated crop with the largest N rate.Forage yields were generally larger with sowing in early May rather than later and maturity was earlier in years with the most accumulated day-degrees.