bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of environmental temperature on the energy metabolism of cattle
Authors: Rogerson A. 
Published: March 2009

1. A relatively inexpensive closed-circuit respiration chamber for cattle is described.2. Experiments with two steers are reported in which heat production and energy retention data were measured at different levels of food intake and at different environmental temperatures.3. The energy lost in faeces increased with improving plane of nutrition but was not significantly affected by the environmental temperature. Urine energy losses fell with increasing environmental temperature at low planes of nutrition. Methane losses increased with improving nutritional plane but were reduced by high environmental temperatures at high levels of food intake.4. The heat production of fasting animals, or animals on low planes of nutrition was not influenced by the environmental temperature in the range 20–40° C. On higher planes of nutrition an increasing environmental temperature increased the animals' heat production.5. The major factor determining energy retention in different environments is the heat production of the animal. Net energy values consequently vary with temperature.
Effect of age and carbon-dioxide concentration on assimilation by detached leaves of tea and sunflower
Authors: Barua D. N. 
Published: March 2009

A simple method has been described for measuring photosynthesis of detached leaves.The reduced rate of photosynthesis of the tea leaf, immediately after excision, is due to stomatal closure. In mature detached leaves, kept well supplied with water in diffuse light or darkness and in a humid atmosphere, normal stomatal opening and maximum photosynthetic rates were obtained between 12 and 30 hr. from excision. Stomata on sunflower leaves do not close on excision.Variation in the initial concentration of CO2between 1·0 and 4·0% vol. with a final concentration not below 0·5% did not affect the rate of photosynthesis of sunflower leaves at 25° C. and under 32 klux light intensity. Under the same conditions of light and temperature, there was no change in the photosynthetic rates of tea leaves in 1 and 2% initial and 0·2% final CO2concentrations. There were indications that CO2concentrations below 1·0% might be rate-limiting for certain tea leaves, assimilating under low light (4 klux).The development of photosynthetic capacity in the young leaves of tea and sunflower is a gradual process. In sunflower, the photosynthetic capacity develops fully before, and in tea after the leaf reaches half its final size.
The measurement of yield, voluntary intake and animal production of tropical pasture mixtures
Authors: Olubajo F. O. , Oyenuga V. A. 
Published: March 2009

SummaryThe consumption of three different tropical pastures by the conventional clipping method and by the nitrogen–chromic oxide technique were assessed and compared over a 2-year period. The clipping method was found to give consistently higher estimates of consumption of herbage dry matter by grazing steers than the chromic oxide method by approximately 16, 14 and 25% respectively for treatments E (Gynodon + Centrosema), F (Mixture E + Stylosanthes) and G (Digitaria + two legumes), when data for the 2 years were pooled for each treatment.The mean live-weight gain over the 2-year period was 0·19 kg per head per day. This figure is essentially in agreement with that obtained for the same group of animals in the previous 2 years. As would be expected the lowest gain was recorded during the dry season when there was little or nothing to graze. It was similarly observed that during a severe attack of trypanosomiasis the animals sustained some losses even though there was abundant pasture to graze.
Application of split-root technique in orthoposphate absorption experiments
Authors: Kalra Y. P. 
Published: March 2009

SummaryThe absorption and translocation of phosphate by roots of intact seedlings of rape, oats, flax and buckwheat were studied. Two hydroponic experiments were conducted in the greenhouse. A split-root technique was used in which a single root of the culture plants was grown in one solution and the rest of the roots in another solution in a twocompartmented glass jar.The presence of other nutrients had a favourable effect on root growth and was essential for efficient phosphate absorption. There was a positive relation between the extent of root growth and phosphorus uptake. On the basis of unit weights of a single root, rape was not any better than oats and buckwheat. A single root of rape, in the presence of other nutrients, absorbed two-thirds of the phosphorus absorbed by all the other roots, whereas single roots of buckwheat, oats, and flax were much less efficient than the rest of the roots. In the absence of other nutrients, single roots of buckwheat, rape and oats absorbed 4·61, 0·18 and 3·49%, respectively, of the phosphorus supplied. However, in the presence of other nutrients, the corresponding values were 21·68, 43·86, and 7·62%, respectively. Both in the presence and absence of other nutrients the single root of flax did not absorb phosphorus from solutions high in phosphate. The results indicate that the age of the plant has an important bearing on the uptake and translocation of phosphorus.
The absorption of subcutaneously implanted thyroxine in the sheep
Authors: Lewis D. 
Published: March 2009

1. Pellets of L-thyroxine (30 mg.) were implanted subcutaneously in sheep. The loss in weight of the implants and the plasma P.b.i. level were determined at intervals.2. The P.b.i. concentration increased within a few days from a normal value of around 5 μg./100 ml. to one of 15–20 μg./100 ml. After 10–20 days the concentration slowly returned to normal, and at 70 days subsequent to implantation was only slightly above the normal level.
The effects of time of ploughing and time of drilling on the development and yield of the winter wheat crop following a clover ley
Authors: Hanley F. , Jarvis R. H. , Whitear J. D. 
Published: March 2009

1. Two experiments designed to investigate the effects of different times of ploughing a clover ley on the growth and yield of the subsequent winter wheat crop are described and the results discussed.2. Although the different times of ploughing led to considerable differences in the growth of the wheat, their effect on yield was not consistent. This in agreement with the results of an earlier series of experiments. The effects of time of ploughing are attributed mainly to the resulting differences in the physical condition of the seed-beds.
Growth and performance of cotton in a desert environment: I. Morphological development of the crop
Authors: Hearn A. B. 
Published: March 2009

SUMMARYVariety, sowing date, irrigation water and plant spacing were the variables in five experiments over three seasons in southern Arabia. The results are used to develop the idea that morphological change and increase in dry weight—two aspects of the growth of cotton which are often studied separately—must be linked to explain or predict crop performance.A straight line related the number of flower buds counted at any time to the number of mainstem nodes on a plant. The mainstem was therefore a simple parameter for the effect of age, temperature and water on the development of plant structure. The relationship was explained by a model in which fruiting branches compete with one another. The structure of the crop plants, as measured by the types and number of nodes, developed along a course in time determined by variety and spacing at a rate dependent on temperature. The rate decreased with age, but was independent of the quantity of water available, until a critical amount had been used, when development stopped abruptly.Accumulated day degrees accounted for the differences between dates of sowing in the subsequent production of nodes. This relationship was consistent with work on temperature elsewhere. Date of sowing effected the position of the first fruiting branch in the variety Bar XL 1 but not in Wild's Early. The position of the first fruiting branch and spacing affected the number of vegetative branches. Wider spaced plants produced flower buds faster only because they had more fruiting branches, a result in turn of more vegetative branches. The ratio between the mean rates of production of nodes on vegetative branches, and on fruiting branches were varietal constants and agreed with results elsewhere in contrasting conditions.
Rapid changes in nitrite after gamma irradiation of fresh soils
Authors: Cawse P. A. , White T. 
Published: March 2009

SUMMARYIncreases in nitrite in ten gamma-irradiated soils have been investigated under aerobic conditions up to 7 days after treatment over the range 0·25–2·5 Mrad. The formation of nitrite showed significant correlations with the percentage of soil inorganic carbon and incubation time, and over 100 ppm nitrite-N accumulated within 3 days in Broadmoor series, which contained the most inorganic carbon. Only the very acid series failed to produce nitrite, but formation and persistence was poor in all soils below pH 7.Leaching with ammonium or nitrate ions after irradiation suggested that microbial reduction of nitrate was the mechanism responsible for nitrite accumulation, rather than inhibition of nitrite oxidation.
Complete diets given ad libitum to dairy cows: the effect of straw content and of cubing the diet
Authors: Owen J. B. , Miller E. L. , Bridge P. S. 
Published: March 2009

SummaryTwelve Friesian cows were given six complete diets ad libitum in an experiment designed as a double 6 × 6 Latin Square balanoed for residual effects. The main energy components of the diets were rolled barley and 20, 35 or 50% chopped barley straw. The diets were given either as a loose mix or extruded through a fin. die. Dry-matter intake, milk yield and solids not fat % declined while butter fat % increased progressively with increased levels of straw in the complete diets which were fed in the loose form. In comparison with the loose diet containing 20% straw, the corresponding cubed diet was associated with a depression in dry matter intake and a decreased butterfat %. In contrast, the oubed diets containing 35 and 50% straw supported higher dry-matter intakes, higher solids oorrected milk yield but lower butter fat % than the corresponding loose diets. The effect of cubing the 35 and 50% straw diets was to make the voluntary dry-matter intakes and lactational performances comparable to those obtained with the loose mixes containing 20 and 35% straw respectively. In general the voluntary intake data agrees with a previously proposed model. However, the depressed intake obtained with the 20% straw diet in the cubed form would not have been predicted by the model. It is suggested that complete diets could be used in large units to combine the low labour costs of self feeding of dry feed with a high degree of control over nutrient intake and laotational performance.
Growth rates and crop morphology in vernalized and non-vernalized swards of perennial ryegrass in spring
Authors: Davies Alison 
Published: March 2009

SummaryRelative growth rates in swards of vernalized plants of perennial ryegrass were one and a half times as great as those found in swards of comparable non-vernalized material. This difference was associated with changes in the distribution of the products of photosynthesis and differences in the scale of losses of dead matter. Changes in sward geometry appeared to be of less importance.
A note on observations on the effect of photostimulation and hormone treatment on the oestrous activity and lambing performance of North Country Cheviot ewes
Authors: Robinson J. J. , Gill J. C. 
Published: March 2009

SummaryTwelve non-pregnant and 20 pregnant North Country Cheviot ewes due to lamb in April 1969 were subjected to an 18 h daylength during the previous December. Thereafter daylength was reduced by 25 min per week. Eight ewes mated naturally in late May and early June and 22 of the remainder mated within 6 days after treatment with progesterone and gonadotrophin. Five of the photostimulated and 14 of the photostimulated plus hormone-treated ewes subsequently lambed in November 1969. The lambs were weaned at 28 days and 16 of the ewes were returned to fertile rams immediately after weaning. All 16 ewes were re-mated to naturally occurring oestrus during January-February 1970 and 13 proved pregnant.
Evaluation of tests for predicting the availability of soil manganese to plants
Authors: Browman M. G. , Chesters G. , Pionke H. B. 
Published: March 2009

SUMMARYEight soil Mn tests, namely, CH3COONH4-, Mg(NO3)2-, H3PO4-, hydroquinone-, 3m-NH4H2PO4-,1·5m-NH4H2PO4- and EDTA-extractable Mn and total Mn were evaluated for their ability to predict Mn uptake by maize (Zea mays L.) on 63 soils of diverse origin. Regression equations were derived by comparing Mn uptake with each test in combination with pH. The best prediction of Mn uptake was provided by a combination of CH3COONH4-extractable Mn and pH; 52·9 % of the variability in Mn uptake was accounted for by these two variables. EDTA and H3PO4-extractable Mn were superior to the other soil Mn tests in predicting Mn uptake.The effect of soil properties on the extractability of soil Mn by each extractant was analysed statistically. Only with hydroquinone-extractable Mn did the soil variables investigated account for a major portion of the variability in the Mn test. The soil variables most often correlated significantly with the Mn test were pH and total Mn. Organic carbon and clay contents were significant only in determining EDTA- and Mg(NO3)2-extractable Mn, respectively.
Calcium metabolism of cows at parturition and during milk production
Authors: Sansom B. F. 
Published: March 2009

SUMMARYCalcium metabolism in dairy cows has been studied at three periods, namely 2 weeks before and 2 weeks after parturition, and also at peak lactation. Of the four parameters studied—percentage absorption from the diet, endogenous excretion, exchangeable pool size and bone accretion rate—only the last showed significant changes, falling at parturition and rising to pre-calving levels subsequently. There was no increase in the percentage absorption of calcium from the diet after calving but total calcium absorption rose because of increased dietary intake.
Seasonal production of Andropogen Gayanus: II. Seasonal changes in digestibility and feed intake
Authors: Haggar R. J. , Ahmed M. B. 
Published: March 2009

SUMMARYTwenty-seven sheep feeding trials were carried out on freshly cut Andropogon gayanus, fed daily during three wet seasons, 1966–8.In each year, dry-matter voluntary intake and digestibility were highest during the first part of the growing season and declined with advancing maturity of the herbage. However, at the time of ear emergence in early October, there were small increases in voluntary intake of dry-matter and crude protein digestibility, although further decreases followed after mid-October.Determinations of in vitro digestibility indicated that elongating stems during early October were at least as digestible as leaves.Seasonal changes in crude protein digestibility were much greater than changes in dry-matter digestibility; seasonal changes in feed intake were intermediate. Voluntary feed intake was related to dry-matter digestibility.Voluntary feed intake and digestible crude protein were both closely related to the crude protein content of the forage. It was concluded that crude protein is a useful criterion for predicting nutritive value.
The effect of date of sowing on the growth and yield of spring cereals
Authors: Jessop R. S. , Ivins J. D. 
Published: March 2009

SUMMARYExperiments to study the effect of date of sowing at two centres in each of 3 years, 1967–9, are described and the results discussed. The earliest sowing date (early March) gave the highest yield of spring barley at both centres and of spring wheat at Sutton Bonington, but at Boxworth in 1967 and 1969 later sowing (early or late April) gave higher yields of grain, which were attributable mainly to increased grain numbers per ear. It is argued that in 1968 poor weather conditions in July and August resulted in very low 1000 grain weights, and although grain numbers were again higher from late sowing at Boxworth this treatment gave the lowest yields because of poorly filled grain. The date of sowing also affected yields of total dry matter, ratios of grain to straw, leaf-area indices, numbers of grains per ear and 1000 grain weights.
Screening potato clones for resistance to common scab (Streptomyces scabies) in the field
Authors: Langton F. A. 
Published: March 2009

SUMMARYPotato varieties were grown in the field in soil uniformly infected with Streptomyces scabies. In 1969 tubers were severely and evenly infected but in 1971 infection was slight and not uniform. Agreement of varietal ranking with agricultural experience was good in 1969 but poor in 1971.In 1971, plots protected from rainfall after planting were dry enough at the start of tubering for severe infection; covering the plots for a further 6 weeks followed by irrigation to field capacity resulted in good yields of evenly and severely scabbed tubers. Irrigation during this period suppressed scabbing. The results were easily interpreted in relation to fluctuations in soil-water content measured by a neutron moisture-meter.The efficiency of using only one site and the need to reduce variability in scab screening tests are discussed.
Effects of nitrogen fertilizer, plant population and irrigation on sugar beet: I. Yields
Authors: Draycott A. P. , Webb D. J. 
Published: March 2009

SUMMARYFive experiments (1965–9) on calcareous sandy loam tested all combinations of four amounts of nitrogen (0–1·8 cwt/acre N) and four plant populations (8000–54 000 plants/ acre) given to sugar beet grown with and without irrigation. On average, nitrogen and plant population influenced yields greatly but irrigation relatively little. In all years between 0·6 and 1·2 cwt/acre N and between 17000 and 32000 plants/acre gave largest sugar yield. Giving more nitrogen or increasing the plant population neither increased nor decreased sugar yield much in any year. Irrigation was beneficial in only two out of five years.Sugar yield was linearly related to root dry-matter yield. Although total dry matter was greatest when the largest plant population was given the largest dressing of nitrogen and irrigation, the proportion of dry matter in the roots was decreased by all three factors.
A study of the theoretical expectation ofF1hybridity resulting from bulk interpopulation hybridization in herbage grasses
Authors: Foster C. A. 
Published: March 2009

SUMMARYA study of the theoretical expectation ofF1hybridity resulting from bulk interpopulation hybridization in herbage grasses has been made. It is concluded that the main factor affecting the percentage interpopulationalF1hybrid content of the seed product of a two-population mixed sward is degree of coincidence of population flowering patterns. The effects of differences in population parameters are examined for a range of population types. Other factors such as differences in total gamete frequencies, preferential fertilization and differential pre- and post-harvest seed losses are also considered.
Studies on selection for yield in wheat. An application of genotypic and phenotypic correlations, path-coefficient analysis and discriminant functions
Authors: Das P. K. 
Published: March 2009

SUMMARYGrain yield in wheat, as in other crops, is a complex character, made up of many subcharacters. In the present investigation the study of genotypic and phenotypic correlations and path-coefficient analysis indicated that 250-grain wt. and ear number were two important component characters in wheat. Under these circumstances it would be desirable to select those plants which produce large number of tillers and very large and bold sized grains. The greater the number of tillers on a plant the greater would be the number of grains/plant. Again large and bold type of grain would obviously give higher seed wt.With the use of discriminant functions it was observed that a maximum genetic gain of 7·44% was obtained when grain yield/plant, 250-grain wt., no. of ears/plant and ear length were included in the function. This would suggest that the discriminant function is superior to straight selection in wheat. However, an expected gain of 4·13% was realized when only 250-grain wt. and grain yield/plant were taken into account. In the present analysis it appeared that relatively more emphasis should be given to grain wt. during selection. To make proper use of such characters in selection, their importance must be considered in the definition of economic worth. Progress measured in terms of yield alone will be less when the economic importance of plant type is ignored.
Growth characters and yield of sorghum (Sorghum vulgare Pers.) as affected by contents of water–soluble P in triple superphosphate/dicalcium phosphate and triple superphosphate/rock phosphate mixtures
Authors: Govil B. P. , Prasad Rajendra 
Published: March 2009

SUMMARYA field experiment was made during the rainy seasons of 1968 and 1969 on a sandy loam soil to study the response of Sorghum hybrid CSH–1 to phosphorus in relation to content of water-soluble phosphate in fertilizers. Triple superphosphate, dicalcium phosphate, rock phosphate (200-mesh), nitrophosphate and mixtures of triple superphosphate with dicalcium phosphate and rock phosphate in 3:1, 2:2 and 1:3 ratios were studied. The amounts of phosphorus applied were 30 and 60 kg P2O5/ha. Phosphorus application significantly affected dry matterproduced, plant height, days to 50% bloom, number of grains per ear, thousand-grain weight, stover and grain yield. Triple superphosphate and 3:1 triple superphosphate/dicalcium phosphate mixture were the most effective while rock phosphate and 1:3 triple superphosphate/rock phosphate mixture the least. Differences among sources were more marked in 1968 and at the higher amount i.e. 60 kg P2O5/ha. The response of sorghum to phosphorus was considerably lowered when the water solubility waa below 50% in triple superphosphate/dicalcium phosphate mixtures and below 75% in triple superphosphate/rock phosphate mixtures. Relative effectiveness was assessed by calculating ‘superphosphate equivalents’ and ‘multiple regressions’. Using superphosphate equivalents dicalcium phosphate, nitrophosphate and rock phosphates were 47–53%, 35–56% and 3–25%, respectively, as effective as triple superphosphate.
Breed and seasonal differences in quantities of lipids on skin surface and hair in cattle
Authors: Pan Y. S. 
Published: March 2009

SUMMARYDifferences between Sahiwals and Jerseys and between summer and winter in the quantities of lipids on the skin surface and on hair were studied.Sahiwals had significantly greater quantities of lipids on both the skin surface and hair in summer and in winter. In both breeds, there were significantly greater amounts of lipids on the skin surface and on hair in winter. In both breeds a significantly greater quantity of lipids was present on hair than on skin in winter but not in summer.Jerseys had greater weight of hair/unit area of skin than Sahiwals in both summer and winter. There was no significant correlation between the amount of lipids on hair and the weight of hair.