bluuebunny/crossref_metadata_2025 huggingface dataset:
Thyroid metabolism in sheep during pregnancy
Authors: Annison E. F. , Lewis D.
Published: March 2009

1. The peripheral metabolism of thyroxine in sheep in pregnancy was investigated by measuring the rate of disappearance from blood of injected131I-thyroxine. Only limited changes in thyroid metabolism during pregnancy were observed. The rate of turnover of thyroxine slightly increased, but this was not accompanied by increased levels of plasma protein-bound iodine (PBI), or thyroxinebinding protein.

2. In a 3·5-month foetus, the thyroid was active, and a marked concentration of iodide by the foetus was observed. The significance of this activity could not be assessed in the absence of knowledge on the placental passage of iodide or thyroxine in the sheep.

3. Knowledge of thyroid metabolism is inadequate at present to explain any correlation between animal productivity and either hormone supplementation, or PBI concentration.
A second survey of losses associated with pregnancy and parturition in Yorkshire sheep
Authors: Leech F. B. , Sellers K. C.
Published: March 2009

Data concerning a random sample of flocks in Yorkshire and Lancashire were collected, in the form of answers to a questionnaire. Information was received from 88% of the 272 farms approached.

The present survey, a more detailed repetition of one performed in 1952–53, has extended the information already collected and enabled deductions to be made regarding the relationship between disease losses, breed and husbandry methods. The advantages and disadvantages of this type of survey are discussed.
Nutritional evaluation of kale (Brassica oleracea) diets:3. Changes in plant composition induced by soil fertility practices, with special reference to SMCO and glucosinolate concentrations
Authors: McDonald R. C. , Manley T. R. , Barry T. N. , Forss D. A. , Sinclair A. G.
Published: March 2009

Nitrogen (0, 150 kg N/ha), sulphur (0, 50, 150 kg S/ha) and molybdenum (0, 400 g sodium molybdate/ha) fertilizers were applied to kale sown in spring on soils either low (4 mg/kg, site L) or high (22 mg/kg, site H) in sulphate (SO4-S). The plots were harvested after growing periods of 100, 160 and 220 days. Dry-matter (D.M.) yields were determined on each occasion and comprehensive plant analyses carried out on material harvested at 160 days.

Nitrogen application increased both the D.M. yield and nitrate content of kale grown at both sites, and increased S-methyl cysteine sulphoxide (SMCO) content in kale grown at site H and in the plots receiving S fertilizer at site L. Glucosinolate content was unaffected by N application in kale grown at site H, but was higher in the absence than in the presence of N in kale grown at site L. Molybdenum fertilizer had no effect upon D.M. yield or upon any aspect of plant composition.

At site H, S fertilizer application produced a range of soil SO4-S values from 10 to 23 mg/kg on day 160 and had no effect upon either kale D.M. yield or composition. At site L, corresponding soil SO4-S values ranged from 4 to 9 mg/kg; as soil SO4-S was reduced, concentrations of plant sulphate declined first, followed by SMCO and then protein-S (% D.M.), with the reductions in SMCO and sulphate being more pronounced in the presence of N application. Glucosinolate and nitrate contents, and the yields of D.M. and protein N, were unaffected by restricting fertilizer S supply.

It was concluded that SMCO synthesis in kale is stimulated by the application of N when soil SO4-S values are high, but is progressively reduced as soil SO4-S declines below 9–10 mg/kg, particularly if N is applied at the same time to stimulate synthesis of plant protein and hence the incorporation of S into protein. Use of this technique to produce kales of low SMCO content for animal feeding is discussed, utilizing tests to define soils initially low in SO4-S. It was further concluded that sulphate and SMCO function as storage of S that is taken up in excess of requirements for plant protein synthesis, thus explaining their ease of manipulation by soil fertility practices.
The effect of dietary oxalate on calcium, phosphorus and magnesium balances in horses
Authors: McKenzie R. A. , Blaney B. J. , Gartner R. J. W.
Published: March 2009

Negative calcium and phosphorus balances were produced in two experiments on six horses fed diets containing 2·6 or 4·3% total oxalate. The main calcium and phosphorus loss was in faeces. The urinary loss of calcium was reduced and that of phosphorus increased. A positive balance of magnesium was maintained. No clinically significant changes in blood concentrations of calcium, phosphorus, magnesium or alkaline phosphatase were produced. The bulk of ingested oxalate was unaccounted for in faeces and urine. It is suggested that the intestinal bacterial flora utilized the oxalate. The results supported the hypothesis that dietary oxalate is the cause of equine nutritional secondary hyperparathyroidism which arises when horses graze several tropical grass species.
Larvicidal effectiveness of three controlled-release formulations of Dursban and Dimilin onCulex pipiensL. andAedes aegypti(L.)
Authors: Saleh M. S. , Gaaboub I. A. , Kassem Sh. M. I.
Published: March 2009

Three plastic formulations of both Dursban and Dimilin were tested as controlledrelease pellets against larvae ofC. pipiensandA. aegypti. Each pellet had an initial concentration of 0·116 μg/l. Results showed that Dimilin did not appear to give as high percentages of larval mortality as Dursban although in most cases a clearly delayed inhibition of adult emergence was noted. Larval mortalities of 90–100% were obtained in 3–14 (in the case of Cpipiens) and 1–12 (in the case ofA. aegypti) days when the second instar larvae were treated with Dursban formulations. With the Dimilin formulations no more than 31% (in case ofC. pipiens) and 24% (in case ofA. aegypti) larval mortalities occurred up to 13–14 days until completion of pupation.

The results obtained showed that formulation 1 (polyvinyl chloride + dibutyl phthalate + toxicant) was the most effective of the three tested ones, followed by formulations 2 (polyvinyl chloride + dibutyl phthalate + triton X·100 + toxicant) and 3 (polyvinyl chloride + dibutyl phthalate + triton X·100 + ammonium carbonate + citric acid + water + toxicant), respectively. This was so on the basis both of percentage of larval mortality and time post-treatment. The durations of effectiveness of Dursban pellets were 123, 94 and 86 days for the formulations 1, 2 and 3 respectively. However, on the basis of number of tests with over 90% larval mortality, formulation 2 gave the highest level (13 tests) followed by formulation 3 (12 tests) and finally formulation 1 (10 tests). Therefore, consideration must be given to the cumulative effect of these factors of activity when using these formulations for control of mosquito larvae. Activity indices also proved that there was no definite variation in the toxicity of both DDT-susceptible and resistant strains against these formulations. Such results were obtained with Dimilin which confirmed that formulation 3 was the most effective one. The durations of effectiveness were about 112–115 (11–67% inhibition of adult emergence), 111–113 (11–93% inhibition of adult emergence) and 102–113 (12–100% inhibition of adult emergence) days for formulations 1, 2 and 3, respectively, for the susceptible and resistant lines of C.pipiensandA. aegypti.
An evaluation of near infra-red reflectance analysis in some plant breeding programmes
Authors: Starr Carol , Morgan A. G. , Smith D. B.
Published: March 2009

Some applications of near infra-red reflectance (NIR) analysis in plant breeding have been tested. Prediction of the nitrogen content of cereals, kale and beans, and nitrogen and oil in rapeseed was sufficiently accurate for screening purposes although wheat straw gave a less accurate result. The prediction of nitrogen content of wheat grain could be supplemented by the simultaneous estimation of grinding resistance and bran cleanliness, characters of importance for bread-making quality. Hagberg falling number, sodium dodecyl sulphate (SDS) sedimentation volume and loaf volume could not be accurately predicted by NIR. Encouraging results were obtained for predicting malting quality of barley and the digestibility of kale samples.
Effect of green manures on yield and nitrogen requirement of sugar beet
Authors: Last P. J. , Draycott A. P. , Webb D. J.
Published: March 2009

Four field experiments in 1972–6 investigated the effect of undersowing trefoil or ryegrass in barley, and of fodder radish sown after barley, on yield and nitrogen requirement of following sugar beet. Autumn applications of isobutylidene diurea or glycoluril (slow-release nitrogen fertilizers) were also included for comparison with green manures. The plots were split in the following spring and dressings of 0, 50, 100 and 150 kg N/ha as ‘Nitro-Chalk’ tested on the sugar-beet crop.

The undersown green manure crops slightly decreased the yield of barley but, at the time of ploughing, returned up to 3·7 t dry matter/ha and 50 kg N/ha. In the absence of spring-applied nitrogen fertilizer for the sugar beet, green manures increased root and sugar yield, but when more than 50 kg N/ha was applied for the sugar beet they had no effect on yield. Autumn applications of nitrogen fertilizers such as isobutylidene diurea decreased the requirement for nitrogen in spring, but yields were no greater than from spring-applied nitrogen alone. Top and subsoils sampled in late winter and early summer from plots where green manures had been grown showed no detectable increase in soil organic carbon or total nitrogen, but soil mineral-nitrogen concentrations were increased slightly by green manures as was the potentially available mineralnitrogen released in an incubation test. It is concluded that, on loamy soils, green manures decrease the nitrogen requirement of sugar beet but give no benefits in yield which cannot be obtained from nitrogen fertilizer in spring before sowing the crop. assistance and Miss G. Smith for statistical analyses.
A comparison of physiological and yield characters in old and new wheat varieties
Authors: Sinha S. K. , Aggarwal P. K. , Chaturvedi G. S. , Koundal K. R. , Khanna-Chopra R.
Published: March 2009

The Indian subcontinent has witnessed a spectacular improvement in yield of wheat during the past decade (Rao, 1978). This is reflected in the improvement of the average national yields as well as of those regions where wheat is grown as an irrigated crop (Sinha & Aggarwal, 1981). However, after the release of the double dwarf variety Kalyansona, only marginal improvement in yield has occurred in recent years. Despite this, the semi-dwarf character continues to be considered a major factor for improvement of wheat. Asana & Chattopadhyay (1970), Konar & Asana (1975), and Wattal & Asana (1976) observed no significant difference in yield between tall and semi-dwarf (medium tall) varieties in pot culture experiments where lodging was prevented and competition was partly reduced. They ascribed prevention from lodging and improvement in the ratio of grain to total above-ground dry matter as major advantages in the modern varieties. Somewhat similar conclusions have recently been drawn by Austinet al.(1980). However, a detailed comparison of various physiological and biochemical characters lias not been made to determine whether any advance has occurred in basic processes such as photosynthesis and nitrogen assimilation. The present study was an effort in this direction.
Conception rates with bull semen diluted in a glycerolized glycine-egg yolk-fructose buffer
Authors: Stower J. , Bud-Husaim P.
Published: March 2009

1. A diluter for semen containing egg yolk, glycine, sodium citrate, fructose and glycerol is described.

2. 2005 inseminations gave an over-all conception rate of 65·7% (90–120 days non-returns) after periods of storage varying from 24 to 196 hr.

3. 401 inseminations after storage for 24–48 hr. gave a conception rate of 75·3%, compared with a conception rate of 60·0% on 398 inseminations after 96–144 hr. storage, using semen from the samecollections.

4. A possible use for modified glycine diluters for nominated service at A.I. centres is suggested.
Lucerne investigations: III. Effect of heat treatment on germination and field establishment of lucerne seed
Authors: Zaleski A.
Published: March 2009

1. Lucerne seed samples of known harvest history were treated by dry heat at various temperatures and durations; their germination capacity, emergence and establishment were tested by laboratory, greenhouse and field establishment tests on heavy Boil during 1952–6 at Cambridge.

2. A successful and safe heat treatment was 42° C. for 5 days, increasing the germination by as much as 44% up to about 90% at the cost of hard seed.

3. The establishment obtained on heavy soil from treated seed samples, although varying from season to season, was significantly higher (P > 0·001) at all seed rates than that obtained from untreated control samples.

4. Significant differences were obtained in germination capacity and establishment between samples harvested at different conditions. High moisture content of seed and high percentage of dark brown seeds was associated with late harvest. Brown seeds had a significantly lower germination capacity than yellow seeds. Only samples with a high initial moisture and high percentage of brown seeds showed a substantial decrease in germination capacity during the storage period of 3 years.

5. Although the mean number of plants established is significantly higher for higher seed rates the mean percentage of plants established decreases significantly with higher seed rates and the greatest wastage of seeds occurred at the high seed rate of 15 lb; per acre.

6. The viability of seed and speed of germination and of emergence were the most important factors in determining the successful establishment of a crop on heavy soil.

7. Hard seed is viable and could germinate and produce seedlings by the end of the season, but only a very small percentage of it could normally be established under field conditions. With untreated seed no significant correlations were established between laboratory germination and field establishment or between laboratory germination and greenhouse emergence, yet there were highly significant correlations in these cases for treated seed. With increased duration of laboratory germination test, corresponding to a decrease in the proportion of hard seed, values of r increased. Correlations between field establishment at three seed rates and greenhouse emergence were significant in the case of both untreated and treated seeds.

8. When the hard seeds were added to germination or establishment the relationships between the results of these tests were very close and highly significant correlations were established for both lots of seed, untreated and treated. The high proportion of hard seeds was the main limiting factor preventing a close relation between tests for untreated seed.
The effect of dietary N onin vitrolipolysis and fatty acid hydrogenation in rumen digesta from sheep fed diets high in starch
Authors: Gerson T. , John A. , Sinclair B. R.
Published: March 2009

Five Romney wethers, fitted with rumen fistulae, were each fed five pelleted diets high in starch (30–50%) containing 0·72, 1·22, 1·72, 2·47 and 3·72% N respectively. Samples of rumen liquor were incubated with glycerol-tri-[1-14C]oleate or with [1-14C]- linoleic acid. The rates of lipolysis or hydrogenation of these substrates were measured. In addition rumen contents of the sheep when fed the 1·22% N diet were incubated with radioactive substrates plus 0, 100 and 200 mg finely ground casein.

It was found that there was an approximately linear increase in the rate of lipolysis between 0·7 and 2·5% N. The rate of hydrogenation did not increase below l·2% N and tended to decrease above 2·5% N. The potential for hydrogenation of unesterified linoleic acid was calculated to be 4–6 times greater with all diets except that containing 1·2% N. This may be one explanation for the elevated concentration of the rumen unsaturated fatty acids in sheep fed diets containingca.1–1·5% N.

It was also established that the addition of finely ground casein to the incubate was without effect.

It was concluded that microbial composition is important in regulating the relative rates of lipolysis and hydrogenation which determined the amount of unsaturated dietary fatty acid present in the rumen.
The availability of iron in certain grass, clover and herb species. I. Perennial ryegrass, cocksfoot and timothy
Authors: Thompson A. , Raven A. M.
Published: March 2009

1. The availability of iron in three species of grass has been investigated using the rat as the experimental animal.

2. Two procedures, namely, the increase in blood haemoglobin concentration, and the gain in total gramme of haemoglobin by nutritionally anaemic rats were employed.

3. Inorganic iron, as ferric chloride, was shown to be significantly more available than the iron contained in the three grasses.

4. The iron in the grass timothy was found to be significantly more available than that in ryegrass or cocksfoot.

5. Possible reasons for the differences in iron availability were discussed.
The normal flora of the bovine rumen. Bacteriological evaluation of rumen contents by the examination of cud
Authors: Davey L. A. , Briggs C. A. E.
Published: March 2009

Quantitative and qualitative bacteriological comparisons were made between complementary samples of cud and rumen contents using five fistulated cows receiving various diets; no marked differences were observed between samples taken from the same animal at the same time. This, with the method of collecting cud described, simplifies bacteriological evaluation of the rumen contents of intactanimals.
The magnesium of bone mineral
Authors: Taylor T. G.
Published: March 2009

1. Fractionation experiments have been described in which powdered bone materials were extracted with dilute acids using three different techniques. Ethylene diamine tetracetic acid (EDTA) was also used in one series of experiments.

2. The results suggested that the magnesium of bone is present in two main forms, one relatively soluble and the other relatively insoluble in dilute acids.

3. It appeared that a large proportion (at least 70%) of the total bone magnesium was located on the surfaces of the bone crystals either as Mg2+ or MgOH+ ions adsorbed at the primary cation adsorbing centres (the surface phosphate ions of the apatite crystals) or as Mg2+ ions replacing surface Ca2+ ions of the crystal lattice.

4. Evidence that magnesium carbonate does not occur in significant amounts in bone salt was obtained.

5. These results were discussed in relation to the hypomagnesaemia of lactating cows.

6. The carbon dioxide of bone also appeared to be present in two main forms, one relatively soluble and the other relatively insoluble in dilute acids.
Irrigation of grassland
Authors: Low A. J. , Armitage E. R.
Published: March 2009

Field experiments are described comparing the yield of herbage on a series of grass-clover plots which were irrigated after various deficits had developed. In addition to the irrigation treatments, different rates of nitrogen were applied.

The maximum yields were obtained when only small deficits were allowed (maximum pF 3·3). This applied particularly to grass-clover swards to which no nitrogen fertilizer was applied.

There was not much reduction in yield on predominantly perennial ryegrass swards liberally supplied with nitrogen when larger deficits were allowed to develop (pF c. 4·0).

Estimates of soil water deficit from meteorological data using Penman's method agreed very well with direct measurements.
Effect of body weight at calving on body-weight changes during early lactation and post-partum reproductive performance in buffaloes
Authors: Bhalaru Surinder S. , Dhillon J. S. , Tiwana M. S.
Published: March 2009

Studies on the effect of body weight at calving on body-weight losses during early lactation and the post-partum reproductive performance of large, medium and small buffaloes revealed that the large buffaloes (weighing more than 550 kg at calving) lost most weight (45·9 kg) and the small buffaloes (weighing less than 475 kg at calving) least weight (4·9 kg) during the first 5 months of lactation. The body-weight loss was maximal in the 1st month of lactation. The reproductive performance (measured as conception rate, number of services per conception and service period) of small buffaloes was significantly (P < 0·05) better than the large buffaloes. These results indicate that body–weight losses during early lactation are affected by the body weight at calving and these losses play an important role in influencing the post-partum reproductive performance. It is therefore suggested that, to improve the reproductive performance, the feeding regimen of buffaloes during pregnancy and after calving should be such that body-weight losses after calving are small.
The inability of horses to absorb calcium from calcium oxalate
Authors: Blaney B. J. , Gartner R. J. W. , McKenzie R. A.
Published: March 2009

Six horses were fed Setaria sphacelata var. sericea cv. Narok hay in a mineral balance experiment and were in negative calcium balance. This should have ensured maximum efficiency of calcium absorption. Only 6·3% of calcium from a single dose of 1·32 kg calcium oxalate was retained by the horses, which supports the suggestion that horses cannot utilize calcium in tropical grasses if it is present as calcium oxalate crystals.
Effect of simazine and prometryne on the growth and nodulation of chickpea (Cicer arietinum L.)
Authors: Kumar S. , Pahwa S. K. , Promila K. , Sharma H. R.
Published: March 2009

Simazine and prometryne applied to the soil surface in pots at 1·6 and 3·2 kg/ha. 2 days after sowing, did not affect germination or early seedling growth of chickpea. Reductions were noticed under all treatments in the leaf dry weight after 28 days and in the length of the main stem after 42 days. Dry-matter accumulation in the shoot was drastically reduced with simazine but not with prometryne. All treatments retarded dry-matter accumulation in the roots with time. Prometryne reduced chlorophyll content during early growth stages and simazine during later stages.

Growth of the rhizobial culture was reduced with increasing concentrations (1–20 mg/1) of both simazine and prometryne. Root nodule initiation was not affected by either of the herbicides but the later production of new nodules and growth of the nodules were reduced in different degrees by various treatments. Overall nodulation was drastically reduced with simazine. Reductions in nodulation with simazine and prometryne appeared to be primarily a case of general root growth reduction. The pink pigment, leghaemoglobin, did not develop at all in the nodules of simazinetreated plants and its concentration was not affected in the nodules of prometrynetreated plants. The N2-fixing efficiency (acetylene reduction) of the nodules was more in the case of prometryne-treated plants and was nil in the case of simazine-treated ones.
Comparison of direct drilling, reduced cultivation and ploughing on the growth of cereals
Authors: Pollard F. , Elliott J. G. , Ellis F. B. , Barnes B. T.
Published: March 2009

The results are reported of two experiments made on a silt loam soil over chalk on downland in southern England. Three primary tillage treatments (ploughing, deep or shallow tine cultivation) were compared with direct drilling for their effects on the growth of spring barley during the years 1969–74 and winter wheat during 1974–8.

No significant differences in barley population density or early growth were recorded. In the first 2 years more grain was produced on the shallow tined and direct-drilled plots than on those that were ploughed, but the differences did not persist into subsequent years. The mean yield of each treatment over the 4 years did not differ.

Significant differences in population density and winter mortality of wheat occurred but these were not consistently associated with differences in yield. In this crop also the mean yields of the cultivation treatments over the 4 years were not significantly different.

It is concluded that choice of primary tillage system on this chalk downland soil was not a significant factor in the production of either spring barley or winter wheat.
The possible use of long chain (C19-C32) fatty acids in herbage as an indigestible faecal marker
Authors: Grace N. D. , Body D. R.
Published: March 2009

The organic matter (OM) intakes of grazing ruminants can be calculated from the digestibility of the OM and faecal OM outputs which in turn are determined indirectly by administering known amounts of indigestible markers such as Cr2O3(Langlands, 1975). The possibility that the C19–C32fatty acids in fresh herbage could be suitable as an indigestible marker for determining intakes of grazing animals was examined. An early report had shown that when ‘Grasslands Ruanui’ perennial ryegrass (Lolium perenneL.) was fed fresh to sheep the C19–C32fatty acids appeared not to be absorbed because their concentration increased from 7·2% of the total dietary fatty acids to 23·9% of the total faecal fatty acids (Body & Hansen, 1978).
Response of dryland wheat to phosphorus fertilizer as influenced by profile water storage and rainfall
Authors: Singh Ranjodh , Chadha R. K. , Verma H. N. , Singh Yadvinder
Published: March 2009

Effects of phosphorus fertilizer, initial profile water storage and seasonal rainfall on yield and water use by dryland wheat on loamy-sand and sandy-loam soils were studied for a 2-year period (1973–5). Plant available water at seeding varied from 62 to 205 mm, seasonal rainfall varied from 62 to 154 mm and available P status ranged from 9·5 to 18·5 kg P/ha. Four rates of phosphorus 0, 15, 30 and 45 kg P2O5/ha were tested. Available water at seeding, seasonal precipitation and the available P status of soil determined the yield response to phosphorus fertilizer. Response to P application was observed up to 15 kg and 30 kg P2O5/ha in loamy-sand and sandy-loam soils respectively. Growth and yield of wheat were highly correlated with the available water at planting plus seasonal rainfall. Total water use did not change in loamy-sand soil, but it increased by 16 mm in sandy-loam soil with the application of phosphorus. The profile water depletion pattern, further, indicates that the fertilized crop used more water from layers below 135 cm in loamy-sand and 22·5 cm in sandy-loam soil.
Effect of potassium and magnesium application to soils on the dry-matter yield and cation composition of maize
Authors: Bedi A. S. , Sekhon G. S.
Published: March 2009

In a glasshouse experiment, fertilizer potassium and magnesium were applied in various amounts to 20 soils differing in the proportion of exchangeable potassium to the sum of the three exchangeable cations, potassium, calcium and magnesium. Maize, cv. Ganga-5, was grown as the test crop.

In soils where the exchangeable cation ratio (K/Σ (K + Mg + Ca), in equivalents) was less than 0·025, potassium fertilizer significantly increased the dry-matter yield of maize. In soils where this ratio was between 0·026 and 0·05, application of potassium fertilizer was beneficial only up to the intermediate amount of 11 mg K/kg soil. Beyond this amount of application, addition of magnesium was necessary to increase yields. In soils where this ratio exceeded 0·05, potassium fertilizer reduced yields.

An optimum ratio of exchangeable calcium, magnesium and potassium appears more important than their absolute amount. Magnesium application to high-potassium soils improved the cation equivalent ratio within the plant and the dry-matter yield.
An inherited arginase deficiency in sheep erythrocytes
Authors: Wright P. C. , Young J. D. , Mangan J. L. , Tucker Elizabeth M.
Published: March 2009

Arginase (EC 3.5.3.1) catalyses the conversion of arginine to ornithine and urea, and is a key enzyme of the urea cycle. The enzyme is present in high activity in various mammalian red cells (Nishibe, 1973, 1974; Owczarczyk & Barej, 1975) and inherited arginase deficiencies have been found in two primate species (Shih et al. 1972; Terheggen, Lavinha & Colombo, 1972). The present paper describes an inherited arginase deficiency in the erythrocytes of certain sheep.
Glutamate and glutamine metabolism in the ovine placenta
Authors: Pell Jennifer M. , Jeacock Marjorie K. , Shepherd D. A. L.
Published: March 2009

The concentration of glutamate and of glutamine was measured in whole blood obtained from a maternal artery, a uterine vein, a foetal artery and an umbilical vein of chronically catherized ewes and foetuses from 100 to 140 days after conception. The activities of glutamate dehydrogenase, phosphate-dependent glutaminase, phosphateindependent glutaminase, glutamine synthetase, γ-glutamyl transferase and glutamine-oxo-acid aminotransferase were measured in placentomes obtained from ewes during a similar period of gestation.

The concentrations of glutamate in blood from maternal vessels remained constant, whereas there was a significant decline (P< 0·001) in the concentration of glutamate in foetal blood. Glutamine concentrations declined significantly (P< 0·05) in maternal blood and in foetal arterial blood (P< 0·001), whereas the concentration of glutamine in umbilical venous blood remained constant.

Mean arterio-venous differences for glutamate indicated that there was no net uptake from or release into maternal blood by the uterus. However, there was a significant (P< 0·02) uptake of glutamate by the placenta from the foetal circulation. Glutamine release from the placenta into the foetal circulation increased as the foetus matured.

Significant activities of glutamate dehydrogenase, γ-glutamyl transferase, glutamine synthetase and phosphate-dependent glutaminase were found in the placenta but there was no significant relationship between the activities of these enzymes and the gestational age of the foetus. The enzyme profile indicated that the placenta has a substantial potential for net glutamine synthesis.

It is concluded that, for a 140-day foetus, the release of glutamine from the placenta accounts for more than half of its nitrogen requirement. Direct placental transfer of glutamine from maternal blood accounts for only one-third of the glutamine released by the placenta into the foetal circulation of a 140-day foetus. Therefore, the remainder of the glutamine is synthesized in the placenta from glutamate. Only one-third of the glutamate required for this placental glutamine synthesis is from the glutamate released by the foetus. The remainder must be derived either from 2-oxoglutarate, as the result of aminotransferase or glutamate dehydrogenase activities, or from glutathione by the action of γ-glutamyl transferase.
The development of winter wheat in the field. 2. The control of primordium initiation rate by temperature and photoperiod
Authors: Baker C. K. , Gallagher J. N.
Published: March 2009

A scheme was developed to describe how the rate at which apical primordia are initiated in cereals depends on temperature and photoperiod. It was used to analyse initiation in field crops of winter wheat (Triticum aestivum L., cv. Maris Huntsman).

For the initiation of leaves and spikelets, a straightforward linear regression of initiation rate R against mean air temperature (Ta) gave base temperatures (Tb) close to 0 °C for leaves and for spikelets. However, initiation rate was also correlated with mean photoperiod (P) and base photoperiods (Pb) of –0·5 h and 4h were established for leaf and spikelet initiation. When R was correlated with the index (T – Tb) (P – Pb), r2 was 0·62 for both leaves and spikelets.
An estimate of the uptake of subsurface soil potassium by crops in two long-term experiments
Authors: Ganeshamurthy A. N.
Published: March 2009

Plant roots may extend as far or farther below the ground than the plant does above. Given ample space the root system of a single plant may have a total spread of 1·2 m in wheat and 2·4 m in maize. Although a major part of the nutrients are absorbed by crops from the surface soil, subsurfacesoil contributions are often substantial. Part of the nutrients applied to surface soil may leach down and accumulate in subsurface horizons which are often exploited by the deep-rooted crops in a crop rotation (Sparks, Martens & Zelazy, 1980). Lysimeter and soil sampling studies have shown a reduction of K movement when soils are cropped (Broadbent & Chapman, 1949; Singh & Brar, 1977). The amount of reduction varies with the crops. Volk (1940) found that losses of applied potassium on a sandy soil over an 8-year period were reduced by 20% by growing a winter legume in the rotation.
The growth and development of cowpeas (Vigna unguiculata)under tropical field conditions: 2. Accumulation and partition of dry weight
Authors: Littleton E. J. , Dennett M. D. , Monteith J. L. , Elstonff J.
Published: March 2009

The pattern of dry weight accumulation and partition of cowpea crops grown in Nigeria is described. For the first 50 days, increase in dry matter was proportional to intercepted radiation. Differences in dry weight between crops were due equally to variations in incident solar radiation, the fraction of this radiation intercepted, and the efficiency with which it was used. The variation in total pod weight from 206 to 312 g/ma resulted from differences in number of pods, mean pod weight being constant. The pod weight ratio was relatively constant and there was a strong relationship between final number of pods and total plant dry weight.
Differential susceptibility to pest damage in agricultural grasses
Authors: Henderson I. F. , Clements R. O.
Published: March 2009

Plots were sown with six varieties of perennial ryegrass, one each of Italian, Westerwolds and hybrid ryegrass, and one each of cocksfoot and timothy, in April 1974. D.M. yield was assessed at four cuts each year, on plots receiving 300 kg N/ha annually, for 4 years. Invertebrate populations and plant survival were monitored at intervals. Half the plots were treated regularly from sowing onwards with the systemic insecticide, phorate. Insecticide treatment increased output generally, but the extent varied from year to year and between grass varieties. The persistence of Italian and hybrid ryegrass varieties was dramatically improved by insecticide treatment. The three diploid varieties of perennial ryegrass studied appeared to be less susceptible to pest damage than the three tetraploid varieties. Shoot-fly larvae (Diptera: Chloropidae) were the major obvious cause of damage.
The residual effect of pasture cobalt applications on some soils in South East Scotland
Authors: McLaren R. G. , Purves D. , Mackenzie E. Jean , Mackenzie C. G.
Published: March 2009

There are extensive areas in Scotland and other parts of Britain where, because of low soil cobalt status, the cobalt concentration of pasture herbage is below the 0–1 /fg/g D.M. regarded as the requirement for grazing ruminants (Agricultural Research Council, 1965). A common method of overcoming the effects of cobalt deficiency in livestock occurring within these areas is to apply cobalt sulphate to the pasture. Following work carried out by Stewart, Mitchell & Stewart (1941, 1942) and Stewart etal.(1946) the standard recommended application of cobalt sulphate for pasture has remained at 2 kg/ha for many years, an application generally expected to last for 3–5 years. However, in South East Scotland there are doubts about the adequacy of such treatment which has led to a reappraisal. Significant increases in uptake of cobalt by herbage following applications to land at this rate are not always observed and sometimes there is no appreciable increase in ‘available’ soil cobalt as determined by acetic acid extraction.
The effect of nitrogen on cereal yields
Authors: Bullen E. R. , Lessells W. J.
Published: March 2009

This paper provides a general review of the effect of nitrogenous fertilizers on the yields of wheat, barley and oats. The results of 270 experiments carried out during the last decade in England and Wales have been examined.

With the exceptions noted below wheat and barley crops have produced a grain response of 3·0–3·5 cwt./acre to a standard dressing of 0·25 cwt. N/acre; this agrees well with earlier results obtained by Crowther & Yates. The widely grown winter wheat varieties, Hybrid 46, Cappelle Desprez, Bersée, Nord Desprez and Atle each produced an average response of more than 4·0 cwt./acre to the standard dressing. Of the spring barleys, Kenia, Proctor and Herta are also of greater than average responsiveness. The average response of spring oats to the standard dressing was only 1·2 cwt./acre.

The number of experiments is insufficient to allow precise conclusions to be drawn on the effect of autumn dressings, but the evidence suggests that in the drier eastern counties autumn nitrogen may give as good a response as the equivalent spring application. Small dressings of nitrogen provide equal responses whether applied early or late in spring; larger applications need to be applied early in spring (March or April) to obtain the highest yields. There is no evidence that divided dressings are more efficient than a single dressing applied in early spring.

For highly responsive varieties of winter wheat and spring barley mentioned above a dressing of 0·6–0·7 cwt. N/acre is recommended, producing a net return of approximately £10 per acre. For other varieties of winter wheat, and for spring wheat and spring barley, the recommended dressing of 0·5 cwt. N/acre produces a net return of about £5 per acre.
The effect of formaldehyde treatment of soya-bean meal and rapeseed meal on the amino acid profiles and acid-pepsin solubility of rumen undegraded protein
Authors: Varvikko T. , Lindberg J. E. , Setälä J. , Syrjälä-Qvist Liisa
Published: March 2009

Soya-bean meal and rapeseed meal treated with 0, 0·4 or 0·8 g formaldehyde/100 g crude protein (N × 6·25) was incubated in the rumen in nylon bags with 10 and 40 μm aperture.

Disappearance of dry matter and nitrogenous compounds was reduced with increasing formaldehyde treatment.

The proportion of acid-pepsin soluble nitrogen in the undegraded residues of untreated and treated soya-bean meal was similar to the original samples. For rapeseed meal the proportion of acid-pepsin soluble nitrogen in the undegraded residues decreased with increasing rumen incubation time. This reduction decreased with increasing formaldehyde treatment.

Concentration of amino acids in the undegraded residues did not generally deviate from those in the original samples. However, a distinguishable decrease in the methionine concentration was observed in all the rapeseed meal samples and in glutamic acid concentration in rapeseed meal treated with 0 and 0·4 g formaldehyde/100g- crude protein.

Most of the changes due to rumen incubation were smaller using the 10 μm bags than using the 40 μm bags. However, the bag pore size did not play a decisive role in the conclusions of the results given.
Nitrogen nutrition and canopy temperature in field-grown spring wheat
Authors: Seligman N. G. , Loomis R. S. , Burke J. , Abshahi A.
Published: March 2009

The canopy of spring wheat grown with an ample supply of nitrogen was generally cooler than the canopy of a nitrogen-deficient crop. The warmer canopy matured 3–5 days earlier. The accumulated temperature difference was sufficient to account for the different times taken to reach maturity.
Nitrogen metabolism in water-restricted Marwari sheep of the Indian desert
Authors: Bohra H. C. , Ghosh P. K.
Published: March 2009

Studies were conducted to evaluate the effect of 50% restriction of normal daily water intake on nitrogen balance, plasma urea concentration and excretion of different urinary nitrogenous constituents (ammonia, creatine, creatinine, urea and undetermined nitrogen) in the Marwari breed of sheep of the Rajasthan desert, India. The results indicated that the reduction in feed intake in water-restricted sheep leads to a reduction in intake and excretion of nitrogen through faeces (P < 0·01) and urine (P < 0·01) of these animals. No sigficant differences in the excretion of most urinary nitrogenous constituents betweenad libitumwatered and water-restricted animals were observed, except for creatine which was excreted in significantly higher concentrations in the urine of the water-restricted animals. On offering waterad libitumfor 3 days to the restricted animals, the plasma urea in these animals dropped from 33·0 to 20·7 mg/100 ml, i.e. almost to the level in the animals wateredad libitum(18·7 mg/ 100 ml). The daily dry-matter intakes of thead libitumwatered and restricted animals were 790 and 488 g, respectively. The digestibility coefficients for dry matter and crude protein of the feed were 47·1 and 27·2%, respectively inad libitumwatered and 56·6 and 39·5%, respectively, in restricted animals. This improvement in the efficiency of digestion in water-restricted sheep may not be due to any enhanced microbial activity in the rumen, but may possibly be due to an increased absorption of feed nutrients in the hind gut of these animals.
Response of Costus speciosus Koen. to nitrogen, phosphorus and potassium fertilizer
Authors: Yadav R. L. , Anwar M. , Singh R. , Singh D. V.
Published: March 2009

Increased demand for steroidal drugs in recent years has prompted a worldwide search for sources of diosgenin other than from species of Dioscorea (Singh et al. 1980). Costus speciosus (Koen.) Sims, an erect perennial herb found growing wild throughout India, has been suggested as one possible alternative source of diosgenin (Dasgupta & Pandey, 1970; Sarin, Bedi & Atal, 1974; Kapahi et al. 1978). Efforts have been made at the Central Institute of Medicinal and Aromatic Plants to increase the diosgenin yield of Costus speciosus by improved agronomic methods. This note is a result of such experiments, in which the effect of different rates of application of N, P and K was studied.
The effect of roughage or concentrate feeding and rumen retention time on total degradation of protein in the rumen
Authors: Ganev G. , Ørskov E. R. , Smart R.
Published: March 2009

Samples of soya-bean meal, groundnut meal, sunflower meal and fish meal were incubated in nylon bags in the rumens of sheep receiving either whole barley or dried grass. For the vegetable sources of protein the rate of disappearance of protein was greater when they were incubated in the rumens of sheep receiving dried grass than in sheep receiving whole barley. The rate of disappearance of fish meal did not vary between sheep fed whole barley or dried grass.

Rate of outflow of protein particles from the rumen was determined by rendering the protein supplement totally indigestible by a treatment with sodium dichromate. The rate of outflow was greatest with sheep receiving dried grass and increased with increasing feeding level.

The mathematical expressions of degradation rate and outflow rate were combined to give the total amount of protein degraded in the rumen for the grass and barley diets at two levels of feeding.

The amino acid composition of residues left in the nylon bags after 9 h of incubation were shown to be almost identical to the amino acid composition of the original protein supplement, indicating that the composition of the amino acid in the undegraded protein entering the abomasum essentially resembled that of the supplements.
The association of dry-matter yield with nitrogen and soluble-carbohydrate concentration in perennial ryegrass (Lolium perenne L.)
Authors: Valentine J. , Charles A. H.
Published: March 2009

The associations between yield, nitrogen and soluble-carbohydrate concentration within S. 23 perennial ryegrass were investigated at three levels of nitrogen application. Controlled growth room conditions were used.

The simple correlation between yield and nitrogen concentration was negative at the low rate of nitrogen application, not present at the intermediate rate of nitrogen and positive though not significant at the high rate of nitrogen. Yield and soluble-carbohydrate concentration were only correlated (positively) at the low nitrogen rate.

At low nitrogen there were ‘efficient’ genotypes with relatively high yield and low nitrogen concentration. ‘Inefficient’ genotypes had relatively low yields and high nitrogen concentration. The majority of genotypes were neither markedly efficient or inefficient. The efficient genotypes at low nitrogen maintained their yield advantage at higher nitrogen levels with average nitrogen concentration and high numbers of tillers. Inefficient genotypes remained relatively stable in yield, numbers of tillers and nitrogen concentration.

Partial correlation indicated an underlying high degree of dependence between yield, nitrogen and soluble-carbohydrate concentration at all nitrogen levels. The association of yield and nitrogen concentration showed a similar trend over nitrogen levels to that obtained using simple correlation. Yield and soluble-carbohydrate concentration were positively related, and nitrogen and soluble-carbohydrate concentration inversely related, when the effects of the remaining attribute were eliminated.

Data extracted from Lee et al. (1977) confirmed that yield and nitrogen concentration for varieties under field conditions varied with level of nitrogen application in a similar manner to genotypes in the controlled growth room. The variety (Melle) could be characterized as being particularly efficient.

Both sets of results indicate that selection for high yield of nitrogen in herbage can best be achieved through selection for yield alone.
The carcass composition of male, castrated male and female pigs resulting from two levels of feeding
Authors: Davies A. S. , Pearson G. , Carr J. R.
Published: March 2009

An anatomical study compared the effects of sex and a twofold nutritional difference in growth rate between 20 and 100 kg live weight, on 63 entire males, castrated male and female Large White × Landrace pigs. While the effect of growth rate was significant for overall fat deposition in the carcasses of all three sexes, it was greatest for the entire male. In contrast, sex and nutritional effects on the distribution of fat and on the proportion and distribution of muscle and bone were small.
Towards more efficient soil-water modelling: moisture profiles with constant surface water content
Authors: Towner G. D.
Published: March 2009

There exists a large body of soil-water theory for ‘modelling’ soil-water movement and distribution. Yet simpler and sometimes cruder methods are often preferred. In part this preference is due to the fact that theory is not yet able to solve completely the more complicated situations that occur naturally, such as the intermittent application or removal of water in the presence of very hysteric soil-water properties. But in many instances it is due to the apparent difficulty of the analysis for the non-mathematically minded. For example, descriptions have been given of soil-water models, based on direct physical arguments, that are in fact finite difference analyses of the governing partial differential equations, but which make no reference to such equations or their existence. Indeed, the impression is sometimes given that soil-water physicists produce unnecessary, irrelevant and complicated analyses for something that is really quite simple. Unfortunately, the simpler approaches bypass possible complications that are revealed by the mathematically based analyses. It is therefore the purpose of this paper to take advantage of the close relation between the two approaches, and to draw attention to the steps that may be taken to avoid or reduce possible difficulties when following the simpler methods. In particular, it is hoped that the paper will lead to a more efficient use of computing facilities.