bluuebunny/crossref_metadata_2025_split huggingface dataset:
A comparison of glutaraldehyde and formaldehyde fixation of isolated pea chloroplasts and its implications for the treatment of herbage for nutritional studies
Authors: West Janet , Mangan J. L. 
Published: March 2009

SummaryPhotosynthetic electron transport, osmotic volume changes and protein loss on osmotic shock were measured in isolated pea chloroplasts after treatment with a range of aldehyde concentrations at various temperatures and times. ADP+Pi-stimulated oxygen production was the most sensitive to inhibition by the aldehyde treatment. With suitable conditions, osmotic volume changes could be prevented and protein losses on osmotic shock reduced to about 1% of the control value, whilst NH3-uncoupled electron transport retained about 40% of its activity. Results showed that basal, ADP + Pi-stimulated and NH3-stimulated O2 production could be used together to indicate the extent of chloroplast fixation thus providing a way of assessing fixation in preparations where osmotic changes are difficult to measure.Glutaraldehyde (M.W. 100) was found to be 60–80 times as effective as formaldehyde (M.W. 30), on a molar basis, in preventing osmotic volume changes and protein loss on osmotic shock.The application of this work for the production of large amounts of glutaraldehyde fixed chloroplasts and of fixed herbage for use as a tool in nutritional studies in ruminant animals is discussed.
Comparisons of anhydrous ammonia with solid ammonium nitrate for spring barley and winter wheat 1967–70
Authors: Rodger J. B. A. , Gill W. D. , Shukla G. K. 
Published: March 2009

SummaryFourteen trials on spring barley and eleven on winter wheat, grown in the east of Scotland, compared the effects on yield of liquified anhydrous ammonia and solid ammonium nitrate at various levels of application.For grain yield, the optimum N level in these trials was about 100–113 kg N/ha. The object of including in the trials N input levels higher than optimum was attained. Yield response to the two forms of N was similar for both wheat and barley at the different N input levels.Winter injection of anhydrous ammonia was less efficient than spring application. Injection of anhydrous ammonia into young wheat resulted in frequent reduction of plant population and, on occasion, loss of yield.At equivalent rates, anhydrous ammonia caused less lodging than ammonium nitrate; it also appeared to be less readily leached from the soil. Ammonium nitrate gave more rapid early growth and this led to a greater proneness to leaf disease.Considering the complexity of storage and injection equipment required to handle anhydrous ammonia, it is questionable if these agronomic advantages justify its use on cereals where rates of use do not also confer the benefits of cheaper unit cost of nitrogen.
The effect of time of sowing and harvesting on growth, yield and nitrogen fertilizer requirement of sugar beet
Authors: Draycott A. P. , Webb D. J. , Wright E. M. 
Published: March 2009

SummaryFour field experiments (1968–71) investigated the effect of changing the length of the growing period on the nitrogen fertilizer requirement of sugar beet. The crop was sown on three occasions (March–May), harvested on three occasions (September–December) and given four amounts of fertilizer (0–225 kg N/ha). Plant samples were analysed at several stages of growth (1969–71) in an attempt to predict the amount of nitrogen fertilizer needed for maximum sugar yield and also at the end of the season to determine the nitrogen uptake. Increasing the length of the growing period increased sugar yield greatly but the amount of nitrogen fertilizer needed for maximum sugar yield was unchanged. The crop given the largest dressing of nitrogen and with the longest growing period contained most total nitrogen, but in every experiment, giving more than 75 kg N/ha neither increased nor decreased the sugar yield significantly. As a result of the small variations in nitrogen requirement, the plant analyses during the growing season were of little value in predicting the needs of the crop.
Quantitative digestion of fresh herbage by sheep: II. The sites of digestion of some nitrogenous constituents
Authors: MacRae J. C. , Ulyatt M. J. 
Published: March 2009

SummarySheep prepared either with a rumen cannula, or with a rumen cannula plus re-entrant cannulae in the duodenum and ileum were fed fresh ‘Ruanui’ perennial ryegrass (R), ‘Manawa’ short rotation ryegrass (M) and white clover (C) at dry-matter intakes ranging from 450 to 1000 g/24 h. Paper impregnated with chromic oxide was given once daily via the rumen fistula as a marker.Amounts of non-ammonia-nitrogen (NAN) entering and leaving the small intestine and nitrogen (N) excreted in the faeces were regressed against the intake of N for each sheep and these equations (all significant P < 0·05) were used to calculate the extent of digestion in the stomach, the small intestine and the large intestine at two levels of OM intake (500 and 800 g daily). Amino acid analyses of feed and digesta samples are also presented together with calculations of the apparent absorptions of individual amino acids from the small intestine.At an intake of 500 g OM amounts of NAN entering the small intestine were significantly greater (P < 0·05) in sheep given M than in sheep given R or C. At an intake of 800 g OM amounts in sheep given M were significantly greater (P < 0·01) than in sheep given R. NAN leaving the small intestine and N excreted in the faeces were similar for all three diets.At an intake of 800 g OM apparent absorptions of NAN from the small intestine of sheep given M (0·47 × N intake + 2·8 g/24 h) and sheep given C (0·51 × N intake – 1·3 g/24 h) were significantly greater (P < 0·01 and P < 0·05 respectively) than of sheep given R (0·41 × N intake – 0·5 g/24 h). As intake of herbage was increased the partition of digestion altered.Only small differences between herbages were found in the amino acid composition (g amino acid/100 g protein) of either duodenal or ileal digesta, but because of the large differences in the flows of NAN, the apparent absorptions of individual amino acids from the small intestine were much higher in sheep given M than in sheep given the other two species.The results are discussed in the light of available information on sites of digestion of herbage diets in sheep.
Agronomic evaluation of Stylosanthes guyanensis and its use in the diet of laying hens
Authors: Onwudike O. C. , Adegbola A. A. 
Published: March 2009

SummaryThe responses of Stylosanthes guyanensis (Stylo) to frequency and height of cutting and the effects of feeding increasing amounts of stylo meal on egg production, yolk vitamin A, yolk colour and percentage hatchability were studied. In the agronomic study, the higher the cutting height, the higher the total yield of dry matter, yield of crude protein, yield of carotene, percentage of crude fibre and the lower the carotene and crude-protein content. A highly significant correlation between the carotene content and crude-protein content (r = +0·91) was obtained.The addition of stylo meal as more than 10% of the feed significantly (P < 0·01) depressed egg production. On the other hand, yolk colour, yolk vitamin A status and percentage hatchability were significantly improved with the feeding of stylo meal.
Game domestication for animal production in Kenya: activity patterns of eland, oryx, buffalo and zebu cattle
Authors: Lewis J. G. 
Published: March 2009

SummaryStudies of the day-time activity of night-enclosed eland, oryx, buffalo and cattle in a hot, semi-arid area in Kenya showed that, on average, eland spent 70% of the day feeding, oryx 60% and buffalo and cattle 52%.The distribution of activity throughout the day of all species was similar and the mobile activities of feeding and walking tended to be concentrated in the early morning and late evening.Correlation and multiple regression analyses were used to investigate changes in the activity of the animals in relation to changes in meterological and vegetative factors. The activity of both eland and buffalo was found to be particularly sensitive to the meterological factors.The duration of feeding for cattle and buffalo was related to the state of the vegetation, but that of the oryx was not. Similar analyses were not possible for eland.The activity of each species could be related to mouth size, feeding habits and the effectiveness of the animals' coat in dealing with conditions of high heat load.It is concluded that a naturally short daily feeding time and an independence of activity from the environmental heat load on the animals are advantageous characteristics for a species under domestication in a hot semi-arid environment.
Water status and yield of sunflowers (Helianthus annuus) subjected to water stress during four stages of development
Authors: Sionit N. 
Published: March 2009

SummaryThe effects on seed yield of two levels of water stress at four stages of development were investigated in two varieties of sunflower, Krasnodarets and Record. The plants were grown from seed in large pots in an air-conditioned glasshouse at 26/20 °C and 70% relative humidity, with natural summer illumination. They were subjected to water stress before head formation, during head formation, during flowering, and during seed development.The leaf water potential of plants subjected to a water stress of – 16 bars returned to normal after rewatering, but plants subjected to – 23 bars did not return to their prestress level and some leaves died. A water stress of – 16 bars caused no significant reduction in dry weight of the vegetative structures, but stress at all stages of growth reduced seed yield. A water stress of – 23 bars reduced both total dry weight and seed yield at all stages of growth, seed yield being reduced more by a stress of – 23 bars than of – 16 bars. Oil content was slightly reduced by water stress.Water stress during anthesis reduced sunflower seed yield more than during later stages of development.
The assessment of genetic variation from normal, self and backcross families of a triple test cross of pure-breeding lines in wheat
Authors: Virk D. S. , Virk Parminder S. 
Published: March 2009

SUMMARYNormal, self and backcross families in a triple test cross were used to investigate the inheritance of number of days from sowing to flowering and dry plant weight for a population of pure-breeding lines of bread wheat (Triticum aestivum L.). Several tests of non-allelic interaction, additive genetic and dominance variances were made that involved triple test cross and single tester analyses. Non-allelic interaction was found to be a component of the genetic variation for both traits. The additive and dominance variances were prevalent for both traits. Alternative estimates of additive genetic and dominance variance components did not differ significantly when tested by a weighted least-squares model fitting procedure. The results are discussed in relation to genetic improvement of bread wheat.
Estimation of the carcass composition of different cattle breeds and crosses from conformation assessments adjusted for fatness
Authors: Kempster A. J. 
Published: March 2009

SUMMARYCarcass data for 1053 steers from the Meat and Livestock Commission's beef breed evaluation programme were used to examine the prediction of carcass composition from conformation-related characteristics corrected to equal fatness. The data were from four trials and comprised both dairy-bred and suckler-bred cattle by a wide range of sire breeds.When used with carcass weight (W) and a visual assessment of carcass subcutaneous fat percentage (SFe) (the most precise simple assessment of carcass lean percentage, residual S.d. = 2·28), m. longissimus area (MLA) at the 10th rib was the most effective conformation-related assessment (residual S.d. = 2·10). Precision was improved by the further addition of a visual conformation assessment (C15) on a 15-point scale (residual S.d. = 2·06). The use of equations combining W, SFe, MLA, C15 and other simple assessments of fatness improved the precision further (residual S.d. = 1·94).The measurement combinations above also provided a significant prediction of the percentage of total carcass lean distributed in the higher-priced joints. Residual S.d.s were: W + SFe, (1·12); W + SFe + MLA (1·07); W + SFe + MLA + C15 (1·06).When the equations were applied to the breed means, there was substantial bias (predicted – actual carcass lean percentage). Bias ranged from approximately + 1·5 (purebred Canadian Holsteins and Luings ) to – 1·6 (Limousin crosses). The accuracy of carcass lean prediction was not improved by the addition of bone measurements to the equations but there was some improvement in the prediction of lean to bone ratio: cattle with light, thin bones tended to have higher ratios.Similar combinations of independent variables were found to provide the most precise prediction within breed.
Field studies on the magnesium, copper and zinc nutrition of maize
Authors: Alloway B. J. 
Published: March 2009

SUMMARYSoils from 55 maize fields in southern and eastern England were tested for available zinc, copper, magnesium and potassium by routine extraction procedures. A high proportion (64%) of the samples contained less than the recommended 50 mg/kg available magnesium, and 24% were within the deficiency range (< 25 mg/kg) for this element. Fewer sites were deficient in copper (7%) and zinc (5%) and these were mainly sandy soils or loams developed on Clay-with-Flints over Chalk. Zinc deficiency in maize does not appear to be a serious potential problem in Britain even though it occurs frequently in other countries, including parts of France.A field of maize with growth problems of varying severity was studied in detail and the available magnesium concentrations found to correlate most closely with the degree of stunting. Soils with healthy plants differed from those in stunted patches of the crop by having higher extractable magnesium, copper and potassium contents. In general the composition of the maize leaves tended to reflect the supply status of the soil, except in the case of chlorotic plants.The influence of factors affecting the availability of the elements investigated and the significance of marginal deficiencies of magnesium and micronutrients in maize are discussed.
Rumen fermentation patterns in sheep receiving silages of different chemical composition supplemented with concentrates rich in starch or in digestible fibre
Authors: Martin P. A. , Chamberlain D. G. , Robertson S. , Hirst D. 
Published: March 2009

SUMMARYIn each of two experiments, eight silages supplemented with concentrates containing a high proportion of either starch or digestible fibre were given to rumen-cannulated sheep. The silages constituted c. 65% of the total dry matter and differed widely in chemical composition, reflecting differences in the extent of fermentation in the silo.Rumen pH was lower (P < 0·01 and P < 0·001 for Expts 1 and 2 respectively) and the concentration of total volatile fatty acids (VFA) in the rumen was higher (P < 0·001 for Expt 2) for the starchy concentrate. Silages differed in their effects on ruminal proportions of acetate (P < 0·001 and P < 0·01 for Expts 1 and 2 respectively) and, inversely, of propionate (P < 0·001 for Expt 1). There was evidence of a strong relationship between the molar proportion of propionate in the rumen and the concentration of lactic acid in the silage. The results indicate that the production of propionate during the metabolism of silage lactic acid by the rumen microbial population was the predominant influence on rumen fermentation pattern.It is suggested that this relationship is the basis of some of the differences in milk production reported for silages showing restricted as opposed to extensive fermentation.
The resistance of new varieties of maize to post-harvest infestation by Sitophilus zeamais Motsch and Sitophilus oryzae (L.)
Authors: Ivbiljaro M. F. 
Published: March 2009

SUMMARYThe indices of susceptibility of five new varieties of maize: TZE 3 (3·01), TZE 4 (6·69), TZSR (5·58) developed at the International Institute of Tropical Agriculture, Ibadan, and MSRB-W (9·53) and MSC-opaque (5·0) at the National Cereals Research Institute, Ibadan, showed that the yellow variety, TZE 3, is the most resistant to post-harvest infestation by Sitophilus zeamais Motsch and Sitophilus oryzae (L.), the latterbeing the more abundant species.Emerging F1 generation adults of either species of Sitophilusdeveloped longer, and were more numerous in soaked maize seeds without testa than in unsoaked, intactmaize seeds. Seed germinability declined as the number of holes per maize seed caused by adult insect emergence increased.
Comparative performance of Mussoorie rockphosphate, single superphosphate and their combinations in potato
Authors: Sahota T. S. , Sharma R. C. 
Published: March 2009

SUMMARYA field experiment on an acid soil of Shillong, in 1982 and 1983, investigated the comparative performance of Mussoorie rockphosphate (MRP), single superphosphate (SSP) and their combinations for potatoes. MRP, when applied alone, proved much inferior to SSP, on an equal P basis, in tuber characters, tuber yield and nutrients (N, P and K) uptake. Application of SSP together with MRP improved the efficiency of the latter. SSP and MRP combinations in 25:75, 50:50 and 75:25 proportions, on a P basis, were 79·3, 95·8 and 101·2% as effective as SSP in terms of tuber production. The response to P was optimum at 70 kg P/ha with SSP and was linear up to the highest rate (105 kg P/ha) with the combinations of SSP and MRP. Concentration of N in tubers declined with the increasing amounts of P, whereas P and K concentrations were little affected.
Effects of fertilizer nitrogen on soil nitrogen availability after a grazed grass ley and on the response of the following cereal crops to fertilizer nitrogen
Authors: Webb J. , Sylvester-Bradley R. 
Published: March 2009

SUMMARYNitrogen nutrition of two succeeding wheat crops was studied after ploughing of grassland in July 1987 on a clay soil at ADAS Drayton. The four plots of grassland had received 100, 250, 450 and 750 kg N/ha per year for 4 years from 1984 and were grazed by beef cattle at stocking densities which varied according to grass growth.Determinations of soil mineral N taken to 60 cm every 3 weeks from July to the following May were particularly variable. However, in the first 2 years after ploughing the means of the series of mineral N measurements were directly proportional to the amounts of fertilizer N applied to the grass.N offtake in winter wheat grain without fertilizer N was directly proportional to fertilizer N applied to grass but this had little effect on maximum grain yields. Large soil N supplies did not necessarily predispose the wheat crops to large grain N concentrations because fertilizer N caused grain N offtake to reach a similar maximum, irrespective of previous grass N.Optimum amounts of fertilizer N for the wheat were 188, 147, 87 and nil kg/ha in 1988 and 152,130, 89 and 25 kg/ha in 1989 after 100, 250, 450 and 750 kg N/ha per year applied to the grass. Soil N supply as indicated by both the amount of fertilizer applied to grass and means of mineral N measurements accounted for almost all of this variation. Mean soil mineral N over winter was no better as an indicator of soil N supply than the amount of N applied to the grass. However, before adopting N applied to grass as a more general index of N supply, it would need to be adjusted for variation in N removed and lost during grass growth; these were controlled in this experiment.
Diallel analysis of competition between diploid and tetraploid genotypes of Secale cereale grown at two densities
Authors: Norrington-Davies J. , Hutto Janice M. 
Published: March 2009

SUMMARYTwo inbred diploid lines of Secale cereale L. and their derived tetraploids were grown together with a commercial diploid and tetraploid in all possible pair combinations in a pot experiment. Comparisons between lines and varieties were made in respect to dry weight measured at 30 weeks.The competitive effects within mixtures were not compensatory, the commercial varieties tending to increase in dry weight more than the homozygous inbred lines decreased. This gave rise to mixture means which tended to exceed their mid-constituent values.The analysis of reciprocal differences in dry weight showed that the effects of competition between any one genotype and its associate in mixtures were constant (alpha competition), the sign and magnitude of the alpha effect being related to the pure stand values of the genotype.The mean effect of competition was to increase the difference in dry weight between genotypes by 2·108 g for each gram by which the genotypes differed when grown alone. In each case the values for genotypes with the higher dry weight increased in mixture whereas the values for those with lower dry weights decreased.Not surprisingly, the commercial varieties were found to be better competitors than the inbred lines, but of more interest was the ineffectiveness of chromosome doubling on competitive ability. Under the conditions of density and fertility reported here, the tetraploid inbred lines could not be distinguished from their diploid progenitors either in their competitive ability or in their reaction to increased density when grown in mixtures. The same is true for the tetraploid and diploid commercial varieties.
Adjustment factors for weaning weights of Mashona cattle in Zimbabwe
Authors: Buvanendran V. 
Published: March 2009

SUMMARYThe effects of year of birth, age of dam, sex of calf, month of birth and weaning age on weaning weights of Mashona calves on six commercial farms in Zimbabwe were estimated by least squares procedures from data of 6365 calves born 1977–85. The least squares mean weight at 205 days among farms ranged from 123 to 159 kg while the linear regression coefficients of weight on age ranged from 0·31 to 0·46 kg. Adjustment for weaning age by the average daily gain from birth to weaning failed to remove the dependence of adjusted weight on age. Sex was the most important source of variation and the mean difference between male and female calves was 12·9 kg. Sex difference was markedly influenced by herd production rate, being greater in herds of above average production.Weights of calves of 3-, 4- and > 11-year-old dams deviated from those of dams aged 5–10 years (mature) by 14·5, 8·5 and 2·9 kg, respectively. Herd mean influenced the difference between 3-year-old and mature dams, the difference increasing as herd mean declined. Herd-year specific factors seem more appropriate for sex and 3-year-old dams and an annual crop of > 50 calves would confer an advantage to herd-specific over general adjustment factors. On the basis of equality of variances within subclasses, multiplicative factors were superior to additive factors for sex of calf and month of birth; both types of adjustment were suitable for age of dam.