bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plant-breeding studies in leguminous forage crops: II. Further observations on natural cross-breeding in winter beans
Authors: Fyfe James L. 
Published: March 2009

1. Using the method given in the first paper in this series, estimates of p and a have been obtained for farm crops of winter beans grown in 1950 and 1951, p being the frequency of a dominant allele, in this case for black hilum, (1 — α) the proportion of successful fertilizations in which the pollen comes from the same plant as the ovule and α the proportion in which the source of pollen may be any plant in the crop. In the 1950 crop the estimates were in the 1951 crop they were The difference in the estimates of p is not surprising in view of the fact that the two crops were grown from different stocks of beans. The difference in the estimates of α is possibly due to the 1951 crop being much the denser.2. In both crops, as in the case previously reported, selection of high-yielding parents produced a frequency distribution of genotypes showing no influence of inbreeding. The data from the 1951 crop failed to give a satisfactory fit with expectation. Both these facts are unexplained by the simple model of a Mendelian population varying at only one locus and with all genotypes of equal fitness. They can both be explained by amending the model so that the population is considered to vary at several loci and that heterozygotes have a slight advantage.3. Theoretically, a bulk made up of the produce of parent plants selected for high yield should contain substantially more heterozygotes than a bulk of produce of unselected parents. This was confirmed by hilum colour counts. Estimates of yield show that the greater heterozygosity is not reflected in any increase in yield. A possible explanation is offered in terms of information theory.
The production of ketonaemia and pregnancy toxaemia in ewes through manipulation of the feeding level
Authors: Gill J. C. , Thomson W. , Park G. T. 
Published: March 2009

1. Trials over 2 years involving 120 Half bred ewes were conducted in outdoor paddocks with controlled feeding. A study was made of the effect of varying the level of feeding during pregnancy on production of ketonaemia and pregnancy toxaemia.2. Blood ketone levels were low and pregnancy toxaemia absent in ewes gaining weight during the latter part of gestation, but ewes failing to gain weight over the same period were subject to ketonaemia and pregnancy toxaemia. A reduction in the ration of fat ewes for a 3-week period, imposed more than 5 weeks before lambing, had no detrimental effect.3. A significant correlation was found between loss in weight and highest ketone figure in the highthroughout and the high-checked groups in 1952 and in the high-checked-high group in 1953.4. High ketonaemia was not always indicative of pregnancy toxaemia, since of the twenty-nine ewes which had, on one or more occasions, over 20 mg. β-hydroxybutyric acid per 100 ml. blood, seven showed signs of pregnancy toxaemia and twentytwo did not.5. In the cases reported, the time of appearance of the first symptoms of pregnancy toxaemia was around 14 days from the estimated lambing date, and affected ewes tended to lamb before term.6. On a comparatively low level of nutrition, only one case of pregnancy toxaemia occurred, though some animals had marked ketosis. In well conditioned ewes reduced to a similar level during the critical period, there was a high incidence of pregnancy toxaemia, and in most of these cases a high degree of ketosis.
Hydrolysis of the cell-wall carbohydrates of grasses by carbohydrases in relation to voluntary intake by sheep
Authors: Jones D. I. H. , Bailey R. W. 
Published: March 2009

SUMMARYThe relationship between the voluntary dry-matter intake of grasses and theirin vitrodigestibility (DOMD), chemical composition and susceptibility to enzymic hydrolysis was examined in two experiments. The grasses were artificially dried and represented a range of species and varieties cut at various growth stages.In both experiments some 70% of the observed variation in intake could be attributed to differences inin vitrodigestibility between the grasses and between the growth stages when harvested. Estimations of acid detergent fibre, pepsin solubility and cellulose generally accounted for less than 70% of the variation in intake.The enzyme digestion techniques, on the other hand, accounted for up to 79% of the variation. The content of enzymically unhydrolysable cell wall gave the highest correlation with voluntary intake (r= −0·88 and −0·89, residual standard deviation 5·5 and 6·2, for the two experiments).It is concluded that simplified techniques based on cellulase digestion of plant material may be advantageously applied to breeding programmes with the expectation of identifying material high in digestibility and with good intake characteristics.
Varietal response by sugar beet to nitrogen, sodium and potassium fertilizers
Authors: Draycott A. P. , Russell G. E. 
Published: March 2009

SUMMARYThree preliminary experiments at Cambridge (1904–70) indicated that several varieties and breeding lines of sugar beet differed in their response to fertilizers. Three factorial experiments were therefore made at Broom's Barn (1970–2) to measure response by four widely differing varieties of sugar beet (Sharpe's Klein ‘E’, Maris Vanguard, V.T.137 and Anglo-Maribo Poly) to nitrogen (0, 75 and 150kgN/ha), sodium (0 and 250 kg N/ha) and potassium (0 and 400 kg K/ha) fertilizers. Increases in sugar yield from 75 kg N/ha by each of the varieties were remarkably similar and giving a further 75 kg N/ha neither increased nor decreased the yield of any variety on average over the three experiments. The yield response to sodium and potassium was greatest in Sharpe's Klein ‘E’ and least in V.T.137; however, as with nitrogen, varieties responded inconsistently from year to year and the interactions were not statistically significant for data pooled over the three experiments. These experiments indicate that varietal differences in fertilizer requirement are unlikely to be important in commercial practice.
Establishment studies II. The effect of method of establishment on a 1 year ley in the seeding year
Authors: Charles Allen H. 
Published: March 2009

The influence of undersowing on the establishment of broad red clover and Italian rye-grass was investigated under three managements and two levels of nitrogen applied in spring. The following conclusions are drawn:1. The cereal cover crop reduced the aggressiveness of Italian rye-grass towards red clover.2. The cereal cover crop produced a high initial yield of dry matter and crude protein. In midseason, when keep from maiden seeds is important, the highest yield was obtained in the absence of the cereal cover crop.3. The danger of failure in the take of undersown herbage seeds is increased when soil moisture is very low.4. Total dry-matter yield in the seeding year was increased by using a cover crop, but starch-equivalent yield was not greatly affected. Crude-protein production was increased when the cover crop was cut for silage or frequently grazed, but not when a grain crop was harvested.5. Undersowing Italian rye-grass and clover gave a higher yield of dry matter, starch equivalent and crude protein than sowing the herbage after the cereal was harvested.6. The cover crop depressed weed growth, and ‘Nitro-Chalk’ increased it, except where Italian rye-grass was undersown.7. The application of ‘Nitro-Chalk’ increased the yield of dry matter, particularly early in the seeding year. ‘Nitro-Chalk’ encouraged the growth of Italian rye-grass and oats but depressed the clover. This reduction in legume yield was least when defoliation was frequent. The influence of nitrogen on plant growth was especially noticeable when soil moisture was low and a cover crop used.
The functional development of the calf II. Development of rumen function in the calf
Authors: Godfrey N. W. 
Published: March 2009

1. Two experiments were conducted to study the development of rumen function in young dairy calves under different feeding regimes.2. The volume of the rumen contents increased with age whereas the volume of the abomasum contents tended to remain constant.3. The concentration of total volatile fatty acids in the rumen liquor of milk-fed calves with free access to pasture reached constant levels at 5 weeks of age. Restricting calves to an all milk diet delayed the development of adult levels of volatile fatty acids until such time as roughage became available.4. Levels of rumen ammonia were high soon after birth but showed a decline with age. An absence of roughage in the diet tended to maintain higher levels of rumen ammonia.5. The pH of rumen liquor showed a steady increase from birth to 17 weeks of age.6. Both volatile fatty acid and ammonia levels in the rumen showed a characteristic diurnal pattern of variation.7. High figures for the digestibility of pasture by young calves were obtained. When calves which had been restricted to an all milk diet were offered roughage they quickly attained a digestive efficiency comparable with calves which had access to pasture from birth.
Studies on the effect of humidity on the hatchability of hens' eggs II. A comparison of hatchability, weight loss and embryonic growth in eggs incubated at 40 and 70% R.H.
Authors: Robertson I. S. 
Published: March 2009

Eggs from Light Sussex hens were weighed before incubation started and on the 19th day of incubation to determine weight loss when incubated at 40% B.H. compared with 70% R.H. They were allowed to hatch and the day-old chicks were weighed.Although the eggs incubated in the drier atmosphere lost more weight, their hatchability was no less than the eggs incubated in the wetter atmosphere. The hatched live weight of the chicks from the respective groups did not differ significantly.The comparatively good hatch obtained here and in part I at the 40% R.H. is suggested as being an indication that for optimum hatchability large eggs may require lower humidity than small eggs.
Factors influencing the role of clover in grass-clover leys fertilized with nitrogen at different rates III. The effects of the variety of companion grass and of the variety of clover on the botanical composition of the sward
Authors: Reid D. 
Published: March 2009

1. In an experiment designed to study some of the factors influencing the role of clover in grassclover swards fertilized with nitrogen at different rates, botanical studies of the sward were made each spring and autumn. The methods used, and the results obtained in the autumn studies, are described in this paper.2. Full details of the experimental treatments and design, and the yield results have been reported previously.3. The botanical composition of the sward depended to a far greater extent on the variety of grass than it did on the variety of clover included in the seeds mixture. This was true also of the yields from the different swards.4. Some relationships are suggested between the yield and nitrogen response results and the variations in the botanical composition of the sward attributable to the variety of grass included in the seeds mixture.5. Kersey white clover appeared to be more persistent than S. 184 and S. 100 where fertilizer nitrogen was applied to the sward, although no differences in persistency were noted in the absence of applied nitrogen.6. A statistical study of the botanical data obtained indicated that the intensity of sampling employed gave the optimum balance between variance and time expenditure, since only a slight reduction in variance would have been obtained if double the number of samples had been taken.
Urea as a fertilizer
Authors: Templeman W. G. 
Published: March 2009

The results of the grassland experiments show that as a straight nitrogen fertilizer urea was, on average, slightly less effective than the conventional materials. In the majority of individual experiments there was no significant difference between the yields from urea and those from ‘Nitro-Chalk’; on the other hand, in a very few experiments the urea yields were much lower. The arithmetic means of the averages in each series of grassland experiments indicate that urea gave total yields about 93% of those from ‘Nitro-Chalk’ and the average response (i.e. difference from control) from urea was about 85% of that from ‘Nitro-Chalk’.The available data for cereals are considerably less than for grassland but here again there is an indication of the infrequent slightly lower efficiency of urea.On kale the results are confusing. At times urea was safe but in one experiment heavy dressings incorporated in the seed-bed caused serious damage.
An intensive cereal-growing experiment
Authors: Hood A. E. M. , Procter John 
Published: March 2009

1. An experiment was conducted at Jealott's Hill from 1945 to 1956 to study yield trends of cereals grown continuously and in four-course rotations including 1-year ‘renovation’ treatments in the form of (a) grazed ley, (b) ley cut for hay and grazed, (c) rape grazed, (d) mustard for green manure, (e) fallow.Winter wheat, spring oats and spring barley were successive test crops common to all rotations and followed the ‘renovations’ or spring barley in the corresponding phase of the continuous cereals system. Main plot (rotation) comparisons were confounded with two levels of nitrogen fertilizer (0·2 and 0·4 cwt. N/acre) and three straw treatments (straw removed, burned or ploughed in) which were applied to all three cereal test crops.All plots except those in fallow received 0·3 cwt. P2O5 and 0·3 cwt. K2O/acre every year. From 1945–48, leys, rape and mustard received 0·2cwt. fertilizer N/acre; from 1949 this dressing was doubled.Grazing of leys and rape was by sheep.2. In the earlier years the highest yields of wheat were obtained in the rotations containing rape, mustard or fallow, but in the later years yields after leys were superior to those in all other rotations. Wheat yields in the continuous cereals rotation soon declined and remained at the lowest level throughout, due largely to severe incidence of ‘take-all’ disease.In the later years yields of barley and oats following 1-year ley were also superior to those in all other rotations.3. In the six cropping rotations compared, all three cereal crops showed very marked responses to applied fertilizer nitrogen, particularly in the later years as the natural fertility of the site declined.
The development of the digestive system of the young animal V. The development of rumen function in the young lamb
Authors: Walker D. M. , Walker Gwen J. 
Published: March 2009

1. A total of twenty-one Merino lambs varying in age from 2 to 11 weeks were slaughtered.2. The enzymic activity of their rumen contents was measured on a variety of carbohydrates and on protein.3. Enzymic activity was expressed as mg. carbohydrate hydrolysed/mg. protein nitrogen/hour.4. When compared with the rumen contents of adult sheep, lactase and proteolytic activity decreased with age; maltase, sucrase and fructanase activity increased; amylase activity decreased from 2 to 11 weeks though adult values were similar to those of the 2-week-old lamb.5. The rumen contents of the lamb were as efficient as those of the adult sheep in their ability to hydrolyse a wide variety of carbohydrates and protein.
Growth and development in the pig, with special reference to carcass quality characters: Part IV. The use of sample joints and of carcass measurements as indices of the composition of the bacon pig: Part V. The bearing of the main principles emerging upon the many problems of animal production and human development
Authors: McMeekan C. P. 
Published: March 2009

1. The accurate measurement of the amount of bone, muscle and fat in the bodies of meat animals is of considerable importance in all technical studies relating to carcass quality. Chemical analysis and laboratory dissection of complete animals are associated with disadvantages which preclude their extensive use. Material derived from nutritional experiments has provided the opportunity for statistical investigation of the possibility of using sample joints and carcass measurements as indices of the composition of bacon pigs of 200 lb. live weight. The extent and nature of the variation in the composition of the pigs concerned adds to the significance of the results obtained.2. The total weight of bone, muscle and fat in the bacon-pig carcass can be estimated with a high degree of accuracy from the respective weights of these tissues in either the loin or the leg. The combination of these two joints provide even higher correlations in each case than either one alone. In all cases the correlation coefficients approach unity and are strongly significant at the 1% point. For the combined joints the values ofrfor bone, muscle and fat respectively are +0·9444, + 0·9765 and +0·9750. Regression functions have been developed for the purpose of estimating carcass composition from these joints.
Diurnal variations in number of ciliate protozoa in the rumen of sheep fed once and twice daily
Authors: Michalowski T. , Muszyński P. 
Published: March 2009

SUMMARYDiurnal changes in number of protozoa were examined in two wethers fed once and twice daily with 0·4 kg of concentrate and 0·4 kg of hay per day. The number of protozoa varied from 4·8 × 105 to 12·5 × 105 cells/ml of rumen fluid, depending on the feeding frequency and time of the day.Entodiniaformed 96·3%,Holotricha2·0%,Diplodinia1·3%, andOphryoscolex0·4% of the total counts. All taxonomic groups of protozoa reached maximum concentration immediately before feeding and decreased by about 60·80% during 4·12 h after feeding. Larger decreases occurred in animals fed once daily.Rumen fluid volume varied from 3·12 to 4·47 l but in different ways due to feeding frequency. Diurnal patterns of dilution rate of rumen fluid were the same in animals fed once and twice daily, showing the decrease from 0·98 1/h at 09·00 h to 0·311/h at 01·00 h. It is suggested that some factors other than dilution rate may be responsible for the decrease of protozoa after feeding.
Yield, seasonal changes in root competitive ability and competition for nutrients among grass species
Authors: Remison S. U. , Snaydon R. W. 
Published: March 2009

SUMMARYRoot interactions between populations ofLolium perenne, Dactylis glomerata, Holcus lanatus and Anthoxanthum odoratumcollected from fertilized and unfertilized plots of the Park Grass Experiment were investigated at two levels of NPK over a period of 3 years.The root competitive abilities of species were dependent on fertilizer applications and changed with time. For example,L. perennewas more competitive at high nutrient application and during the early stages of the experiment. On the other hand, the root competitive ability of H. lanatus was greatest on unfertilized soil and increased with time. The large effect of root interaction on plant yield and the effects of fertilizer application on this, may be regarded as evidence of competition for one or more of the elements, N, P and K. H. lanatus, the most aggressive species, was more competitive on the unfertilized soil (NIL) than on the fertilized soil (NPK). However, this could not be confirmed by chemical analysis of plant material; there was no conclusive evidence that aggressive species contained higher concentrations of these nutrients when grown in mixtures with less aggressive species. The possibility of allelopathy, the production of toxins by one plant which inhibit the growth of another, cannot be precluded.The root competitive ability of species and populations was not positively correlated with the yield of species and populations in pure stand. Indeed, negative correlation was found especially on unfertilized soil. In this case varieties or species with a low yield in pure stand were highly successful root competitors in mixtures, while those with high yield in pure culture were poor root competitors.
A comparison of two non-radioactive digesta marker systems for the measurement of nutrient flow at the proximal duodenum of calves
Authors: Beever D. E. , Kellaway R. C. , Thomson D. J. , MacRae J. C. , Evans C. C. , Wallace Annie S. 
Published: March 2009

SUMMARYThe use of non-radioactive ruthenium phenanthroline (Ru-P) and chromium EDTA (Cr-EDTA) as dual phase markers of digesta flow was examined and compared with chromium sesquioxide (Cr2O3) in conjunction with spot samples of digesta collected from T-shaped cannulae situated in the proximal duodenum of weaned calves.In vitro estimates of organic matter digestibility indicated that on a cubed barley diet, Ru-P exhibited toxic effects at concentrations on 2·2 × 10–5 M and above. No such effects were noted with Cr-EDTA. Subsequently satisfactory infusion rates of 12 mg Ru and 280 mg Cr/kg dry-matter intake were established.Daily flows of organic matter, starch, nitrogen, fibre, sodium and potassium at the proximal duodenum were calculated by the dual phase marker system and by Cr2O3, and regression equations relating these two for each dietary component were calculated. Examination of the intercepts revealed that they all differed significantly from zero (P < 0·05) whilst all the regression coefficients were significantly different from unity (P < 0·05), thus indicating that Cr2O3 underestimated nutrient flows at low flow rates and overestimated them at high flow rates relative to the corresponding estimates based on Ru-P plus Cr-EDTA.
Liquid manure as a grassland fertilizer. III. The effect of liquid manure on the yield and botanical composition of pasture, and its interaction with nitrogen, phosphate and potash fertilizers
Authors: Drysdale A. D. 
Published: March 2009

1. In an experiment conducted for the 3 years 1961-63 on a perennial rye-grass and white clover sward a split-plot design was used to investigate the effects of liquid manure (cow urine + water) and its interactions with various levels of nitrogen, phosphate and potash fertilizers on the yield of herbage and on the botanical composition of the sward.2. On the average the liquid manure contained 0.26% N, 0.44% K and had a pH of 8.6.3. The liquid manure treatments supplied 0, 50, 100, 200 and 400 lb. N/acre/year and 0, 87, 174, 349 and 697lb. K/acre/year. The fertilizer nitrogen treatments were 0, 100 and 200lb. N/acre; the potash treatments 0 and 166 lb. P/acre and the phosphate treatments 0 and 66lb. P/acre.
Post-harvest changes in seed ofLoliumspecies
Authors: Stoddart J. L. 
Published: March 2009

1. The point at which continued development of a seed no longer depends upon attachment of the culm to the root system can be termed rootindependence.2. Serially harvested inflorescences ofLolium temidentumL. were maintained in a glasshouse under the same environmental conditions as standing material. Samples for analysis were taken from harvests and standing material at 2 days intervals to compare chemical changes occurring in seed on standing and severed culms. Analyses for total soluble carbohydrate (T.S.C.) were performed on a single seed basis.3. Harvests made before the seed T.S.C. maximum resulted in oscillating changes in endosperm free sugar content and these caryopses tended to stabilize at an excessively high value. All later harvests resulted in seed with a final T.S.C. level within 1% of that present in normally matured seed4.14C-Sucrose uptake studies showed that tho endosperm T.S.C. requirement was high prior to the seed T.S.C. maximum but that it was very low during the second half of the maturation sequence. It is considered that during this period sugar is only translocated to make good respiratory losses.