bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nutrient metabolism and rumen micro-organisms in sheep fed a poor-quality tropical grass hay supplemented with sulphate
Authors: Morrison M. , Murray R. M. , Boniface A. N. 
Published: March 2009

SUMMARYA feeding trial was performed during 1986, in Townsville, Australia, to describe alterations in nutrient metabolism, and the coincident gross changes in rumen microbiology, when a sulphurdeficient diet was supplemented with inorganic sulphur. Eight Merino sheep were fedad libituma spear grass (Heteropogon contortus) hay of low sulphur content (0·4 g/kg DM), supplemented with all other essential minerals. Upon supplementation, daily sulphur intake was increased toc.0·75 g and four animals continued to be fedad libitum(group A) whilst the remaining animals were restricted in feed intake (group B). Sulphur supplementation caused a twofold increase in the feed intake of group A (P< 0·05). In both groups of animals, sulphur supplementation increased the fermentation of cotton thread cellulose (P< 0·05), as well as of ground plant dry matter (P< 0·05), suspended in the rumen in nylon bags for 24 and 48 h. The apparent digestibility of organic matter (AOMD) was also increased by sulphur supplementation; from 30·6 to 39·3% in group A (P< 0·05) and from 35·1 to 41·5% in group B (P> 0·05). The difference in AOMD between groups with sulphur supplementation was not significant, despite group B maintaining a longer retention of fluid digesta in the rumen (20·7 v. 25·3 h) with a significantly lowered rumen volume (4·68 v 3·67 litres,P< 0·05) and outflow of fluid digesta from this site (5·31 v 3·58 litres/day,P< 0·05). Sulphur supplementation increased the molar proportion of acetic acid in rumen fluid (P< 0·05) but lowered propionic and butyric acids in group A (P< 0·05). Only the molar proportion of propionic acid in rumen fluid was significantly lowered in group B (P< 0·05). In both groups of animals, counts of fluid-borne rumen bacteria, protozoa and sporangia of rumen anaerobic fungi (RAF) all increased significantly with sulphur supplementation (P< 0·05 in all instances), but no significant differences were observed between groups in microbial counts, despite the different feeding regimes. The increase in sporangial forms of RAF was most marked; no sporangial forms were detectable until the diet was supplemented with sulphate and measurable concentrations of rumen sulphide were observed. This is the first account of nondetectable concentrations of RAF brought about by the nutritional status of the diet.
Flowering and pod and seed development in pigeon pea (Cajanus cajan)
Authors: Togun A. O. , Tayo T. O. 
Published: March 2009

SUMMARYFlower, pod and seed development were studied in the cultivars Cita-1 and Cita-2 in two field trials in 1985–86, in Ibadan, Nigeria. Flowering within any inflorescence was acropetal. On each plant the terminal inflorescence was the first to flower and, generally, inflorescences developed basipetally. A total of 569 flowers (mean of five plants) opened on Cita-1; of these, 20 were on the terminal inflorescence, 130 on axillary inflorescences and 419 on inflorescences on primary branches. For the 605 flowers (mean of five plants) which opened on Cita-2, the distribution was 19, 161 and 425, respectively.On Cita-1, 158 pods formed on average, of which 7 were on the terminal inflorescence, 33 on axillary inflorescences and 118 on inflorescences on primary branches lower down the plant. On Cita-2, for the 185 pods counted at maturity, the distribution was 8, 43 and 134, respectively. Some 72 and 69% of the total number of flowers which opened on Cita-1 and Cita-2, respectively, were aborted. In both cultivars, 99% of the mature pods were formed from flowers which opened within 24 days of the start of anthesis; the number of pods retained largely determined seed yield. The inflorescences which developed on the primary branches contributed 70% (Cita-1) and 66% (Cita-2) of the total seed yield. Early-formed pods were heavier than those formed later. Individual pods attained physiological maturity 35–42 days after successful pollination of the flower. At physiological maturity of the pod, the seed contained 3·72 % N, 0·45% P and 2·76% K, and the husk contained 1·98% N, 0·16% P and 1·96% K. The majority of open flowers which aborted were produced on primary branches, indicating that the primary branches have the greatest potential for increasing seed yield. A shorter flowering period might ensure greater retention of open flowers.
Seasonal changes of ingesta mean retention time and forestomach fluid volume in indigenous camels, cattle, sheep and goats grazing a thornbush savannah pasture in Kenya
Authors: Lechner-Doll M. , Rutagwenda T. , Schwartz H. J. , Schultka W. , Engelhardt W. V. 
Published: March 2009

SUMMARYThe study was carried out in northern Kenya in 1984–87. Forestomach volumes and digesta retention times were measured using Cr-EDTA or Co-EDTA as fluid markers and Ce-labelled particles or Cr-mordanted particles as paniculate phase markers.Mean retention times of fluid and of particles were longer in the dry season than in the green season in all four animal species. The increase of particle mean retention time, as a percentage of the values in the green season, was highest in sheep (46%), followed by cattle (27%), goats (22%) and camels(18%). Forestomach volumes were also greater in the dry than in the green season; the increase was again highest in sheep (55%), followed by cattle (31%), goats (29%) and camels (28%). Outflow rates of fluid from the forestomach and the selectivity factor, by which small particles were retained longer in the forestomach than fluid, did not differ significantly between the seasons.It is suggested that the increase of forestomach volumes is an effective adaptation to dry-season pasture conditions. It enables the animals to retain feed particles longer in the forestomach and so improve fibre digestion when feed quality is low. Cattle and sheep, which depend on a poor quality diet, improve fibre digestion in this way in the dry season more effectively than camels and goats. Camels and goats, on the other hand, were able to select a diet of such quality, even in the dry season, that their need to augment fibre digestion was reduced.
Changes in the baseline of the Crop Water Stress Index for lucerne (Medicago sativa) over 3 years
Authors: Rechel E. A. , DeTar W. R. , Ballard D. 
Published: March 2009

SUMMARYThe ability to detect and measure water stress accurately is critical for optimizing crop production. The Crop Water Stress Index (CWSI), the linear relationship of the difference between foliage and air temperatures as a function of the air vapour pressure deficit, is one widely used method. Under well-watered conditions, a ‘baseline’ is derived that is crop specific and presumed fairly constant, despite differences in development and physiology. This study reports changes in the baseline of the CWSI for lucerne crops not subjected to water shortage over 3 years. Studies of lucerne in California from April 1986 to October 1988 used the CWSI to plan irrigations. It was necessary to re-establish the baseline periodically throughout the experiment. In the first year it was similar to that reported in the literature, but in the second year it had a statistically significant steeper slope and higher intercept. In the third year, the regression equation was similar to that in the first year. The changes in the baseline are thought to be a result of crop age rather than year-to-year weather fluctuations. The baseline needs to be determined periodically as the crop matures, to ensure accurate interpretation of plant water stress.
Influence of autoclaved or irradiated Aspergillus oryzae fermentation extract on fermentation in the rumen simulation technique (Rusitec)
Authors: Newbold C. J. , Brock R. , Wallace R. J. 
Published: March 2009

SUMMARYA rumen simulation device (Rusitec) was used to compare the effects of autoclaved and γ-irradiated Aspergillus oryzae fermentation extract (AO) with those of untreated AO on rumen fermentation. Each vessel received daily 18 g of a basal diet consisting of 500 g hay, 299·5 g rolled barley, 100 g molasses, 91 g fishmeal and 9·5 g of a minerals and vitamins mixture/kg dry matter. AO preparations (0·25 g/day) were added with the feed. Dry matter digestion increased at 24 h, but not at 48 h, after adding AO, suggesting that AO stimulated the rate of digestion but not the extent. AO increased the numbers of total and cellulolytic bacteria by 90 and 50%, respectively. Irradiated AO stimulated numbers of bacteria in the same way as AO, although to a slightly lesser extent. Autoclaved AO had no effect. Thus, the mode of action of AO on rumen fermentation depends on a heat-labile component, possibly a nutrient or an enzyme, or metabolic activity. Viable AO cells are not required to stimulate bacterial growth and activity.
Effects of bentonite on fermentation in the rumen simulation technique (Rusitec) and on rumen ciliate protozoa
Authors: Wallace R. J. , Newbold C. J. 
Published: March 2009

SUMMARYBentonite (2 g/day) was added to four vessels in the rumen simulation technique (Rusitec) and the effects on the fermentation were compared with four control vessels over a 21-day period. Vessels in both groups were supplied with 20 g/day of a diet containing, per kg, 500 g hay, 299·5 g barley, 100 g molasses, 91 g fishmeal and 9·5 g of mineral/vitamin mix. Numbers of ciliate protozoa were reduced by 69% (40v. 12·8 ×103/ml) in vessels receiving bentonite. The viable count of bacteria was increased by one-third in these vessels (4·8v. 3·6 × 108/ml), and ammonia production was 54·7 and 76·7 mg/day in the bentonite and control vessels, respectively. Other effects on fermentation products and metabolic activities were minor, except that the rate of breakdown of [14C]leucine-labelledSelenomonas ruminantiumprotein was 47% lower in fluid taken from vessels receiving bentonite. Bentonite did not affect the rate of bacterial breakdown by protozoa immediately when it was added to rumen fluid invitro, although a decline in activity was becoming apparent after 4 h incubation. Microscopic examination of rumen fluid to which bentonite was added indicated that some bentonite was ingested by protozoa, but that its main toxic effect was at the cell surface, causing interference with the motion of cilia and thereby preventing motility of protozoa, particularly the holotrichs.
Ultrasonic scanning for determination of stage of pregnancy in the llama (Lama glama): a critical comparison of calibration techniques
Authors: Iason G. R. , Elston D. A. , Sim D. A. 
Published: March 2009

SUMMARYMeasurements of foetal head diameter (HD) and trunk diameter (TD) were made using ultrasonic scanning of 11 pregnant llamas (Lama glama). Each llama was scanned fortnightly to obtain measurements of HD and TD from c. 84–271 and 65–168 days since mating respectively. There were approximate linear relationships between TD and days after mating and between HD and the logarithm of days after mating.Calibration equations for predicting the number of days after mating (d) from foetal measurements constructed using (i) the inverse method in whichdis regressed on HD or TD and (ii) the classical method in which HD or TD are regressed ond. These calibration methods were assessed by crossvalidation, treating each animal in turn as the individual for which predictions were required. Analysis of the prediction errors showed bias in the classical method, which consistently underestimateddat low values. A components of variance analysis indicated substantial variation between individuals which must be taken into account in calculating standard errors of prediction (S.E.P.) and confidence intervals. S.E.P. ofdfrom TD can be reduced from 12·5 to 10·4 days by increasing the number of observations on an individual from one to four at fortnightly intervals. For prediction from HD, the equivalent figures are size dependent: examples are from 8·3 to 5·6 days, and from 26 to 18 days, for HDs of 2 and 6 cm respectively. The effect of small positive correlations between residuals of successive fortnightly measurements on the same llamas had a negligible effect on S.E.P.S, increasing them byc. 0·2 days. Ultrasonic scanning is suitable for determination of stage of pregnancy of llamas providing S.E.P.S which are small in relation to their long gestation period (335–360 days).
Intake, rumen volume, retention time and digestibility of diets based on poultry litter and wheat straw in beef cows before and after calving
Authors: Brosh A. , Holzer Z. , Aharoni Y. , Levy D. 
Published: March 2009

SUMMARYBeef cows in the 14 weeks before calving and during the first 12 weeks after calving were fed one of three diets based on 15, 30 and 45 % broilers poultry litter (PL), 20 % maize grain (MG) and 65, 50 and 35% wheat straw (WS) on a DM basis, respectively. They were housed from June to November in individual open pens. Four weeks before and 9 weeks after calving, in vivo digestibility, fibre and fluid mean retention time (MRT) were measured. The intake of all diets before calving was low. Nine weeks after calving the intake of DM increased 2·1 times on the 15% PL diet, and 1·6 times on the two other diets. The in vivo digestibility of the 15% PL diets was lower than that of the two other diets before calving, and increased after calving, in spite of the doubling of its intake, while that of the 45% PL diet decreased. The mean retention time of fibre in the digestive tract was not affected by the increase in DM intake after calving on the 15 % PL diet and was shortened on the two other diets. It seems that the combination of the volume taken up by the gravid uterus and the bulkiness of the 15% PL diets (65% WS) reduced the intake and impaired the digestibility of that diet before calving. After calving, the fibre pool increased considerably and consequently both intake and digestibility were increased.
Analysis of size-grouped potato yield data using a bivariate normal distribution of tuber size and weight
Authors: Hall J. E. , Glasbey C. A. 
Published: March 2009

SUMMARYA bivariate normal model is proposed for the joint distribution of potato tuber size and weight. Parameters in the model are estimated from the yields and numbers of tubers in a range of riddle-size categories. The method is illustrated using data from a field experiment; parameters are estimated for each plot, and subjected to analysis of variance. The result is a more succinct summary of treatment effects than that produced in the traditional analysis, where data from each riddle size are analysed separately.
A method for calculating the population/yield relations of groundnut (Arachis hypogaea) in semi-arid climates
Authors: Azam-Ali S. N. , Nageswara Rao R. C. , Craigon J. , Wadia K. D. R. , Williams J. H. 
Published: March 2009

SUMMARYBetween 1980 and 1986, six field experiments were conducted to investigate the relations between planting density, total dry matter and pod yield of groundnut (Arachis hypogaeaL. cv. TMV2) grown at different levels of irrigation and rainfall at two sites in central India. In general, the relationship between total dry matter and planting density for most treatments was well described by the function:where W is the crop dry weight per unit ground area,wmis the maximum weight per plant, Wmis the maximum crop weight per unit ground area and P is the plant population. Because the harvest index,h, was constant for each treatment irrespective of plant population, a similar equation described the relationship between pod yield and planting density. When nine of the eleven treatments planted in a square (i.e. 1:1) arrangement were compared, the asymptotic value Wmvaried between treatments depending on available soil water and atmospheric demand. To quantify the effects of plant and environmental factors on crop productivity, a ‘transpiration equivalent’ (ωw; (g/kg)/kPa), i.e. the product of the dry matter/water ratio and mean seasonal saturation deficit D, was used as a crop constant to calculate productivity at each site or season from a knowledge of seasonal rainfall and/or irrigation and soil water-holding capacity. Thus, total crop productivity, W'8, was calculated using the equation W'8= ωwS/D where S (mm) is a soil supply term dependent on soil water-holding capacity and monthly values of rainfall and/or irrigation. When values for Wmand W'8were plotted against each other, a linear regression was obtained with a slope = 1·02 (R2= 0·78). The mean harvest index of 0·38 was used to predict pod yield from a knowledge of W'8. It was concluded that of all the climatic, soil and management factors that influence crop growth in semi-arid situations, it is the interaction between the supply of and demand for water that ultimately determines total productivity, pod yield and optimum plant population.
Effects of cultivation and nitrification inhibitor on soil nitrogen availability after a grass ley and on the response of the following cereal crop to fertilizer nitrogen
Authors: Webb J. , Froment M. , Sylvester-Bradley R. 
Published: March 2009

SUMMARYThree experiments carried out at Bridget's Experimental Husbandry Farm, Hampshire between 1984 and 1987 on clay loam and silty clay loam soils over chalk investigated the response of winter wheat grown after grass to spring-applied fertilizer nitrogen. The influence of method of establishment and the use of a nitrification inhibitor were also studied. Yields were similar whether the crops were established by direct drilling or following ploughing. Crops required between 88 and 209 kg N/ha nitrogen fertilizer for optimum yield. There was no consistent difference in nitrogen requirement nor were there consistent differences in nitrogen offtake (which is the amount of N in kg/ha removed in harvested grain) or apparent fertilizer recovery following ploughing or direct drilling. The use of a nitrification inhibitor increased grain yield when applied in the autumn without fertilizer, but not when applied with fertilizer in the spring.
Effect of insect pollination on seed production in linseed (Linum usitatissimum)
Authors: Williams I. H. , Simpkins J. R. , Martin A. P. 
Published: March 2009

SUMMARYThe effect of bee visits to the flowers on flower longevity and capsule, seed and oil production in linseed (Linum usitatissimum L.) cv. Antares, was investigated in two very different growing seasons (1988 and 1989); plots caged to exclude insects, plots caged with a honeybee colony and plots uncaged and open-pollinated by honeybees and bumblebees were compared. The experiments were conducted at Rothamsted Experimental Station Farm in Hertfordshire.Although honeybee visits to the flowers resulted in earlier petal fall, they did not increase capsule or seed production. It is concluded that the crop is self-fertile, self-pollinates well, and that inadequate pollination is not a factor limiting yield.
A method of assessing the yield stability of crop genotypes
Authors: Westcott B. 
Published: March 2009

SummaryA method of assessing genotypic stability is proposed in the case where genotype yields are measured across environments but no concomitant environment data are available. The method is introduced in a practical context and two examples of its use with actual data are presented.The method depends ultimately on the choice of a suitable measure of similarity between genotypes. Most of the stability information appears in a sequence of plots, where stable genotypes are immediately highlighted as consistently more remote points.
The growth and yield of winter wheat following 10 years of continuous ploughing, shallow-tine cultivation or direct drilling on a non-calcareous clay soil
Authors: Ayling Sarah M. , Bacon E. , Christian D. G. , Goss M. J. 
Published: March 2009

SummaryThe growth and grain yield of winter wheat were measured in plots which had been direct drilled, mouldboard ploughed or shallow-tine cultivated for 10 consecutive years. The experiment was carried out on a non-calcareous clay soil prone to winter waterlogging. In 1985 the crop grew well on all cultivations and grain yield, average 7–2 t/ha, was similar in all treatments and no adverse effects on wheat growth or on grain and straw yield were observed.
A study of field drain ochre deposits. 2. The distribution of micro-organisms
Authors: Dbwi I. Ap , Johnson D. B. , Kelso W. I. 
Published: March 2009

SummarySheathed filamentous bacteria,Leptothrixspp. andGallionellaspp., were observed in ochre samples from sites in England and Wales.Thiobacillus ferrooxidanswas found in acidic samples (pH < 4·0) and in ochre from drainage water of near neutral pH suggesting that it can contribute to ochre formation over a wide range of drainage water pH, Heterotrophic bacteria capable of growing in artificial media of low pH and complexdegrading heterotrophic bacteria were also isolated. Some ochre deposits could be described as either pyritic or filamentous but the majority of samples fell between these extremes and had various combinations ofT. ferrooxidans, sheathed filamentous bacteria and other heterotrophic bacteria.
A comparative in vitro digestion trial using inocula of livestock from South Turkana and Kitale, Kenya
Authors: Coppock D. L. , Ellis J. E. , Waweru S. K. 
Published: March 2009

SummaryThe dry-matter digestibilities of 13 important herbaceous and browse forages from an arid rangeland in north-western Kenya were evaluated in a comparative in vitro trial using rumen fluid from indigenous sheep, goats, a camel, and Merino sheep kept at an agricultural laboratory. All inoculum donors had varied diets preceding the experiment, but little substantial difference was observed in the ability of each fluid to digest test materials. Tt was concluded that the Merino sheep inoculum provided an adequate substitute for inocula from indigenous animals for studies of the nutritional ecology of free-ranging livestock.
Observations on resistance in white clover (Trifolium repens L.) to the stem nematode (Ditylenchus dipsaci (Kühn) Filipjev)
Authors: Cook R. , Evans D. R. 
Published: March 2009

SummaryThe expression of symptoms of stem nematode reproduction on a total of 53 white clovers (26 cultivars, 14 genepools and 13 introductions from plant collections) was studied in a series of field and glasshouse experiments. Seedlings or stolon-tip cuttings were inoculated with nematodes and the clovers classified by the proportion of plants which developed symptoms. Significant differences were found between varieties although in each test the majority was intermediate between more resistant and susceptible extremes. There was significant positive correlation between tests, in spite of different inoculation methods and different average levels of susceptibility. Very large-leaved cv. Aran was more resistant than most other clovers tested, and small-leaved cv. S. 184 was more susceptible. There was no general correlation of leaf size with reaction to stemnematode. Small-leaved cv. Pronitro was also resistant while several large-leaved cultivars were susceptible. In observations of plants exposed to nematodes over a long period, either by sequential inoculations or through perpetuating latent infections, apparently resistant plants eventually succumbed and supported nematode reproduction. It has not been determined whether this was because selection for virulence in the nematodes had occurred.