bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth analysis of the domestic fowl I. Effect of plane of nutrition and sex on live-weights and external measurements
Authors: Wilson P. N. 
Published: March 2009

101 Rhode Island Red × Light Sussex chickens have been made to conform to four differently shaped growth-curves from hatching to 24 weeks, by control of their plane of nutrition. The four treatments HH, LH, HL and LL allowed comparisons to be made between birds of the same age but different weights.As the main concern has been to find the essential nature rather than the precise extent of the effects produced by different planes of nutrition, the treatment differences were made as extreme as possible without allowing the rations to become unbalanced.The conclusions reached are as follows:1. The treatments used have produced marked effects on the growth-curves of the birds, analysed on the basis of equal age. These effects have been shown to be statistically significant at all stages after 3 weeks.2. In body-weight and form, two types of bird were produced. The HH and LH birds were similar, with greater relative proportions of the late developing parts and secondary sexual characteristics, and the small differences that existed between them were not significant at 24 weeks. Likewise, the LL and HL birds formed a comparable group, exhibiting a more infantile body form similar to that of the HH and LH birds at an earlier age. The differencebetween the HL and LL birds, though generally not statistically significant, is greater than that between the LH and HH group.3. The treatments produced a small but consistent effect on the external measurements of the birds when comparisons were made on the basis of equal weight. Nine measurements were recorded. In the case of four measurements, no treatment effect was noted. Four skeletal measurements demonstrated a consistent effect of treatment, the LL and HL measurements exceeding those of the HH and LH at equal live-weights. This result was reversed in the case of the only muscular measurement, thickness of leg musculature. Opposite results are therefore indicated for the muscle and skeletal tissues. This finding will receive further discussion when the dissection analysis results are discussed in a later paper.4. The presence of definite growth-gradients from the body extremities towards the trunk is indicated by the external measurements.5. The two sexes differ in their live-weights at equal age and in their bodily proportions both at similar ages and similar weights. The most marked sex-difference in external measurement is noted in the length of the mid-wing, and a possible functional explanation is advanced. In general, the sex-difference is greatest for the late maturing characters.
Physiological acclimatization of fowls to a hot humid environment
Authors: Hutchinson J. C. D. , Sykes A. H. 
Published: March 2009

1. The resting heart rate of cocks and hens was measured in varying degrees of heat stress, and during acclimatization to heat.2. When the rectal temperature was below 110°F. (43·3° C), the heart rate varied inversely with the severity of the climate up to an air temperature around 99° F. (37·2° C).3. At air temperatures of 99° F. (37·2° C.) and above the heart rate was nearly constant over a wide range of rectal temperatures below 110° F. (43·3° C). It averaged about 50 beats/min. less than in an equable climate.4. Above 110° F. (43·3° C.) there was an increase of about 30 beats/min./° F. (17 beats/min./° C.) rise in rectal temperature. The rate equalled that found in an equable climate, when the rectal temperature reached 111–112° F. (43·9–44·4° C). Over this zone of body temperature the fowls were often agitated.5. In severe heat stress there was a slight fall in the heart rate on acclimatization, but this was small compared with the effect of climate.6. In severe heat stress the heart rate during the day was slightly higher than that at night.7. The relation of these findings to the mechanism of temperature regulation is discussed.
The effect of spacing on the growth of two genotypes of perennial ryegrass
Authors: Simons R. G. , Davies Alison , Troughton A. 
Published: March 2009

SummaryTwo clones of perennial ryegrass were planted along the radii of a fan in such a way that any group of four adjacent plants was approximately square, with spacings ranging from 3 to 30 cm. During the first year the amount of regrowth per vegetative plant was found to be related to the area available at the high densities, whereas at low densities there was little change in weight per plant with change in density. At high densities the number of tillers declined following defoliation, but at low densities it increased consistently. In the second year, the ratio of fertile to barren tillers was lower and ear emergence was later at high densities. Results indicated that the performance of the clones differed in each of three stages of regrowth. It appeared that early regrowth was better in the erect clone, but after the first week, and where the canopy remained open, the RGR of the prostrate clone was greater. In a dense sward the crop growth was greater in the erect clone indicating that better use was made of the available light.
Variation in muscle fibre diameter among sections and intrasections and between contralateral muscles in seven bovine muscles
Authors: Johnson E. R. , Beattie A. W. 
Published: March 2009

SummarySectional and intrasectional variations in muscle fibre diameter over a restricted axial range were examined in seven bovine muscles from foetuses, calves and steers. Significant sectional variations were found in four muscles, while two muscles showed significant intrasectional variations. The results indicate that sampling sites require accurate definition in comparative studies of muscle fibre diameter.Two extensor muscles of the foreleg, m. extensor carpi radialis and m. extensor digitorum communis showed neither sectional nor intrasectional variation in muscle fibre diameter and appear to be more satisfactory muscles for use in muscle fibre growth studies than m. longissimus thoracis et lumborum.A comparison of mean muscle fibre diameter in 60 pairs of contralateral muscles showed that there were no significant differences in 52 of the muscle pairs.
The incidence of precipitins to Micropolyspora faeni in cattle fed hay treated with an additive to suppress bacterial and mould growth
Authors: Wiseman A. , Dawson Christine O. , Pirie H. M. , Breeze R. G. , Selman I. E. 
Published: March 2009

SummaryThe development of precipitins to Micropolyspora faeni in cattle fed hay treated with a bacterial and mould inhibitor is compared to that in herds fed untreated hay. The results indicate that, even when fed only treated hay, exposure to M. faeni was such that a considerable proportion of precipitin-free cattle did develop precipitins.
The effects of fatty acids on pure cultures of rumen bacteria
Authors: Henderson C. 
Published: March 2009

SummaryThe effects of fatty acids, at low concentrations (0–005-O5 g/1), on the growth of seven species of rumen bacteria were examined.Anaerovibrio lipolytica(strain 5 S),Peptostreptococcus elsdenii(type 2),Bacteroides ruminicola46/52 andSelenomonas ruminantium(strain 17) were unaffected by addition of oleic acid to the medium. Growth ofButyrivibrioB 835 was stimulated by low concentrations of oleic (< 0–01 g/1), lauric (< 0–1 g/1) or capric (< 0–1 g/1) acids while higher concentrations of these acids were inhibitory. Myristic, palmitic and stearic acids were inhibitory at all concentrations tested.Ruminococcus4263/1 was inhibited at all concentrations of the six acids. Production of methane by pure cultures ofMethanobacterium ruminantiumwas also inhibited by the additions of long-chain fatty acids. Oleic acid was the most inhibitory of the series of acids. These results are consistent with the reported effects of lipids on rumen function.
Effect of soil water potential on growth and yield of sunflower (Helianthus annuus)
Authors: Sionit N. , Ghorashy S. R. , Kheradnam M. 
Published: March 2009

SummaryThe effect of soil water potential of the root media on the vegetative growth, seed and oil yield of sunflower (var. Record) grown in containers under field conditions was investigated.The weight of shoots and the total leaf area of plants before flowering significantly decreased with decrease in the water potential of the root media. There was a sharp reduction of shoot weight as the potential decreased from —0–32 to — 1–25 bars and then a further slow decline as soil water potential dropped to — 8'6 bars. There were no significant differences in the 100-seed weights and percentage. of oil among the treatments, but the total number of seeds was significantly different.The data did not indicate the existence of a threshold water potential above which yield was independent of soil water potential, but rather that yield was a continuously decreasing function of soil water potential.
Pregnancy diagnosis in cows; changes in milk progesterone concentration during the oestrous cycle and pregnancy measured by a rapid radioimmunoassay
Authors: Heap R. B. , Gwyn Merle , Laing J. A. , Walters D. E. 
Published: March 2009

SummaryThe progestagen concentration of milk was measured in cows, at various times of the reproductive cycle by a competitive protein binding procedure and by radioimmunoassay. The apparent progesterone concentration was found to be significantly greater in milk (P <0–05) than in plasma, probably due to the presence of an unidentified metabolite(s). A simple, rapid radioimmunoassay was developed to measure directly the progestagen concentration in milk. A mean concentration of about 1 ng/ml at oestrus (or mating) increased, 20–24 days later, to 3–4 ng/ml in cows subsequently found to be non-pregnant and to about 7 ng/ml in pregnant animals. The possible application of this analytical procedure as the basis of a method of pregnancy diagnosis is discussed.
The effect of imposed light rhythms on semen production of Suffolk rams
Authors: Jackson G. , Williams H. LL. , Jackson G. , Williams H. LL. 
Published: March 2009

SummaryThe effects of two, symmetrically opposing, light treatments on the semen of Suffolk rams were investigated over two years. The light rhythm had an amplitude of 12 h and a cycle of 24 weeks. Data on semen volume, spermatozoa concentration, total spermatozoa per ejaculate, fructose concentration, seminal fluid fructose concentration and total fructose were collected during 38 semen collection periods. During the last 20 periods libido was assessed on the interval to mounting.The effects of treatments were assessed by fitting Fourier curves with 24-week cycles to the observed fluctuation of the differences between treatments and with 52-week cycles to the means of treatments. From periodic regression analysis of the treatment differences it is concluded that the Suffolk rams were susceptible to the artificial light rhythms and that both groups adapted to the imposed rhythms. Some effects of the pretreatment photic environment appeared to persist during the first year of the treatment period. There appeared to be a lag between the fluctuations of the semen attributes resulting in a series of sequential changes.
Efficiency of the utilization of the energy of food in piglets, after weaning
Authors: Burlacu G. , Băia G. , Ionilă Dumitra , Moisa Doina , Taṣcenco V. , Viṣan I. , Stoica I. 
Published: March 2009

SummaryThe efficiency of utilization of the energy of food by weaned pigs of the Large White breed was measured. Three diets based on maize (40–60%) had a metabolizable energy of 75·8±1·2% of the gross energy, and 78·2 ±3·4% of the metabolizable energy was present as net energy.The maintenance requirement of metabolizable energy of pigs weighing 14·3 ± 2·1 kg was 143·6 kcal/kg°0·75/24 h (601 kJ/kg0·75/24 h).The energy cost per g protein and fat synthesized by piglets was estimated to be 7·43 and 12·05 kcal (31·1 and 50·4 kJ) metabolizable energy, respectively.Equations for calculation of metabolizable energy (Yl, kcal) and of the net energy (Y2, kcal), based on digested nutrients, were:Y1 = 4·64×1 + 9·12×2 + 4·25×3'CV = ± 1·2%,Y2 = 3·84×1 + 7·09×2 + 3·28×3'CV = ± 1·4%,where X1 = g protein digested, X2 = g fat digested, X3= g carbohydrate digested (crude fibre × N-free extracts).
The yield of sugar beet in relation to weather and length of growing season
Authors: Scott R. K. , English S. D. , Wood D. W. , Unsworth M. H. 
Published: March 2009

SummaryAn experiment at Sutton Bonington in 1971 tested the effects of sowing and harvesting dates on yield of sugar beet. Seed sown on 28 March germinated slowly in the cold soil and crop establishment was poor. From early April until the beginning of May the loss in yield of sugar consequent upon delaying sowing by 1 week was 0·4 t/ha. For later sowings the yield loss was greater. During the harvest period the rate of increase in sugar yield was the same for all sowings. Yields of crops sown and harvested on different dates were closely correlated withthe amount of solar radiation intercepted by the leaf canopy.
Effects of weather conditions on the response of lettuce to applied fertilizers
Authors: Greenwood D. J. , Cleaver T. J. , Niendorf K. B. 
Published: March 2009

SummaryFertilizer experiments on lettuce were carried out over 5 years on adjacent sites of the same soil. The shapes of the response curves to both N and P varied considerably from experiment to experiment even though the amounts of those nutrients that could be extracted from the soil did not show this variation. Responses to N were of an ‘overturning’ type and the level of N at which maximum yield occurred ranged from 50 to 400 kg/ha. Responses to P were of a ‘diminishing returns’ type and the maximum increases in yield brought about by applying P ranged from 75 to 700% of the yields obtained with no application.A mathematical model was derived which fitted the results from all the experiments satisfactorily. The parameter denning the response to P, and that denning the ‘downward’ component of the response to N were linearly related to the integral of cumulative rainfall with respect to time. Insertion of these relations into the model led to an overall model that predicted lettuce yields for each treatment in each experiment from the values of two weather parameters, the levels of N, P and K and a fitted value for seed weight. This overall model accounted for about 75% of the total variance due to fertilizer applications in the nine experiments. It is argued that most of the year-to-year variation in fertilizer response could be explained in terms of rain influencing the adverse osmotic effects on growth, the leaching of nitrate down the soil profile and dispersion of P from phosphate fertilizer granules especially in the early stages of growth.The model was slightly improved by replacing the parameter ‘time’ with cumulative evaporation from an open water surface, but not with cumulative day degrees, or cumulative evaporation divided by vapour pressure deficit.
Weed control and its effects on yield ofPhaseolus vulgarisbeans in Malawi
Authors: Ayonoadu U. W. U. , Norrington-Davies J. , Edje O. T. , Mughogho L. K. 
Published: March 2009

SummaryA number of herbicide treatments involving the use of trifluralin, preforan and igran were compared together with hand weeding as methods for the control of weeds in a cultivar ofPhaseolus vulgarissown on 19 January 1972.Favourable increases in yield of beans were obtained by combinations of preforan and igran which were associated with an increase in the number of pods produced per plant. Hand weeding failed to give a significant increase in final yield.Within 14 days from sowing there was an appreciable weed cover in the control and hand-weeded plots but little evidence of weeds in the herbicide-treated plots. At 41 days there were still no significant differences between the control and the plots to be hand weeded. There was, however, a considerable reduction in percentage cover of weeds on the herbicide treated plots. Trifluralin and preforan were equally effective in reducing weed cover.
Some mathematical aspects of the clover, grass, and fertilizer nitrogen relations
Authors: Stewart D. A. , Chestnutt D. M. B. 
Published: March 2009

SummaryThis article attempts to discuss the relations between the nitrogen sources in data from a large field experiment in which various levels of fertilizer nitrogen were applied to various grass mixtures in the presence and absence of white clover. It was seen that a number of effects occurred, among them the strong depression of clover nitrogen by fertilizer nitrogen (to the extent that equations predicting their contribution to grass nitrogen could not be produced directly by multiple regression but had to be constructed separately), a further apparent depression of clover nitrogen transfer effectiveness, a more significant relationship between grass nitrogen increase and the previous year's clover nitrogen than the current year's clover nitrogen, and apparent competition between grass and clover despite the latter's contribution to increased grass yield.As some of the effects are counteractive, in each comparison made a balance appears to exist. This varies between sites and years in such a way that although the variation in grass nitrogen is always largely dependent on the clover and fertilizer nitrogen the relations are not consistent as shown by the mathematical equation representing them, and cannot be extrapolated or predicted for other sites. It is suggested that a mathematical model be constructed to simulate such an interactive system and that predictions when necessary be made using this, rather than using simple equations.
Crossbreeding and the effect of certain environmental factors on body weights of Barki and German Merino sheep
Authors: El Kouni M. H. , Karam H. A. , Galal E. S. E. , Afifi E. A. 
Published: March 2009

SummaryBody weights at birth, weaning, yearling and 2 years of age were studied on 710 lambs born from 1956 to 1967 and representing Barki, Merino and their F1 and backcross. Body weights ofthe lambs of the two cross-bred groups were intermediate between those of the two pure-breds at birth and exceeded them at weaning. Merino lambs were 0·61 kg heavier than Barki lambs at birth and maintained that advantage throughout the study.Age of dam, type of birth, sex, and year of birth were significant sources of variation on the weights studied. The effect of age of dam and type of birth declined after weaning while that of sex increased.
An empirical model relating crop yield to weed and crop density and a statistical comparison with other models
Authors: Cousens R. 
Published: March 2009

SUMMARYA hyperbolic model relating crop yield to weed density is extended to include crop density as a further variable. Other models were obtained from published sources, eight being originally applied to yield of above-ground biomass and six to marketable yield. Data were obtained from a field experiment in which spring wheat and spring barley were planted either in monoculture or together and at a range of densities. Further data were obtained from a published experiment onSinapis albaand barley grown in containers. The models were fitted to data using maximum likelihood estimation. Comparisons of residual sums of squares showed that for the wheat and barley field experiment biomass yield and marketable yield were sufficiently described by a three-parameter model. The Baeumer & de Wit (1968) equation proposed for replacement series experimental designs is considered reasonable for the analysis of field additive designs provided the parameters are interpreted in agronomic terms. For theSinapis albaand barley experiment more complex models could be justified.
A comparison of fungicides for the control of mildew on spring barley
Authors: Wale S. J. , Hunter E. A. 
Published: March 2009

SUMMARYA series of 24 standardized, replicated field trials comparing 47 fungicidal treatments for the control of spring barley mildew have been analysed. The joint analysis has enabled stronger conclusions to be drawn about the relative efficacy of treatments than examination of individual trials. To increase sensitivity the trials were divided into those with high or low mildew pressure. Under high mildew pressure, the treatments which gave the greatest control of mildew also gave the highest yields. However, within any given treatment the yield response appeared not to be closely related to the degree of mildew control achieved. It is concluded that effective fungicides may have a phytotonic effect as well as a mildew control effect.
Heavy metal uptake from contaminated soils by six varieties of lettuce (Lactuca sativa L.)
Authors: Crews Helen M. , Davies B. E. 
Published: March 2009

SUMMARYA replicated pot experiment is described in which six lettuce varieties were grown in four contaminated soils of different Cd, Cu, Pb and Zn concentrations. Webb's Wonderful absorbed least and All Year Round absorbed most Cd and Zn from all four soils. Uptake of both metals by all six varieties increased with increasing soil contents and leaf Cd and Zn concentrations were positively and significantly correlated. There was little evidence for a varietal control of the absorption of Pb and none for Cu, but a significant positive correlation between leaf Cu and Pb concentrations was observed.
A simple and rapid method of quantitatively measuring the glucosinolate concentration of rapeseed
Authors: Smith D. B. , Parsons D. G. , Starr Carol 
Published: March 2009

SUMMARYA method is described in which glucosinolates are simultaneously extracted from crushed seeds and degraded by myrosinase. Glucose released by myrosinase is measured by an autoanalyser using a single reagent.Using conditions optimized for samples of 200 mg, yields were slightly greater than those obtained from corresponding samples of defatted meal. Coefficients of variation of about 4% were obtained over a range of more than 100 μmol of glucosinolate/g seed. It is suggested that the method will be of value to plant breeders selecting from populations having low and intermediate concentrations of glucosinolate and to others wishing to obtain a rapid but precise measurement of these important compounds.
Vesicular-arbuscular mycorrhizae of winter and spring cereals
Authors: Buwalda J. G. , Stribley D. P. , Tinker P. B. 
Published: March 2009

SUMMARYThe importance of mycorrhizal infection for the growth of wheat and barley sown in winter and spring was assessed in two field experiments. Low temperatures during winter restricted the development of mycorrhizal infection, and calculations of ‘thermal time’ indicated that the percentage of root length infected did not increase when mean temperatures were less than 5 °C. Hence infection was less in the winter-sown crops than in the spring-sown crops at early stages of plant development. However, the effects of mycorrhizal infection on growth were greater in winter-sown than in spring-sown wheat.At all levels of applied phosphorus up to 60 kg P/ha, artificial inoculation with mycorrhizal fungi increased the yields of both cereals at each sowing date by 17–25% after indigenous mycorrhizal fungi had been removed by fumigation, but the effects were smaller on non-fumigated plots. The results confirmed the potential importance of mycorrhizal infection for the growth of cereals.Mycorrhizal infection increased the phosphorus concentration in the plant tissue at very early stages of growth, but the effect generally declined with time.