bluuebunny/crossref_metadata_2025_split huggingface dataset:
The estimation of the intake of grazing sheep II. Application of faecal nitrogen regressions to a group of grazing sheep
Authors: Pearce G. R. , Vercoe J. E. , Tribe D. E. 
Published: March 2009

1. Recordings of faecal organic matter (O.M.), faecal N% (O.M. basis) and live weight, were made over 52 consecutive weekly periods on ten Corriedale wethers grazing a pasture consisting mainly of Wimmera rye-grass (Lolium rigidum Gaud.) with some subterranean clover (Trifolium subterraneum) in a Mediterranean-type environment. The amount of available O.M. and its N% were also recorded.2. By applying regressions of (i) the ratio of O.M. feed intake to O.M. faecal output on faecal N% and (ii) the N% in the O.M. intake on faecal N%, to the above observations it was possible to estimate the following quantities: O.M. and digestible organic matter (D.O.M.) intake, N and digestible N intake and O.M. digestibility percentage.3. The patterns of O.M. and D.O.M. intake, and N and digestible N intake are described. Similar patterns exist for each of these quantities. Two maxima, a large one in the spring and a smaller one in the autumn, and two minima, one in the summer and one in the winter, are exhibited. The values for these various maxima and minima are presented in the text.4. Attention is drawn to variations from the general pattern for these quantities and factors which could influence these patterns are mentioned.
The development of the digestive system of the young animal. VI. The metabolism of short-chain fatty acids by the rumen and caecal wall of the young lamb
Authors: Walker D. M. , Simmonds R. A. 
Published: March 2009

1. Rumen and caecal wall tissues were taken at slaughter from lambs varying in age from newborn to 11 weeks. The ability of these tissues to metabolize the short-chain fatty acids, acetic, propionic and butyric acid was compared with tissues from adult sheep. Ketone body production was measured.2. The utilization of butyrate by the rumen wall in the newborn lamb was lower than in the adult, but exceeded the adult levels at 3 weeks of age and maintained this higher utilization to 11 weeks and probably longer. Ketone body production was negligible at birth but followed butyrate utilization closely thereafter.3. The caecal wall in the newborn lamb utilized butyrate at a much higher rate than the adult sheep tissue. Foetal lamb caecal tissue utilized butyrate to the same extent as in the newborn lamb. Levels were, however, typical of the adult within a day or two of birth and showed no subsequent effect of age. Ketone body production was negligible at all ages.4. Rumen development in milk-fed lambs slaughtered at 7 and 9 weeks of age was retarded anatomically and showed decreased capacity in the utilization of butyrate.5. The utilization of acetate and propionate by rumen and caecal tissues showed no marked change due to age. Ketone body production from these acids was low.
The effect of CCC, nitrogen and potassium on the growth and yield of two varieties of potatoes
Authors: Gttnasena H. P. M. , Harris P. M. 
Published: March 2009

SUMMARYThe two experiments described here were the 3rd and 4th in a series of experiments investigating the effect of time of application of nitrogen and potassium on the growth and yield of potatoes.The effect of applying all the fertilizer nitrogen in the seed bed was compared with applying all the nitrogen at the time of tuber initiation or dividing the dressing between these times. Similar times of application were tested for potassium. CCC was applied after a leaf area index of 3 had been reached (on all but the no N treatments) in order to offset the tendency for late nitrogen to increase stem growth, but to avoid any tendency for CCC to depress yield by reducing leaf area indices (L) below an assumed optimum value of 3. These treatments were applied in separate experiments to a second early variety (Craig's Royal) and a maincrop variety (Pentland Dell), planted a month later.In both crops the response to nitrogen was large and delaying or splitting the application of nitrogen increased tuber yield compared with nitrogen applied in the seed bed. Responses to potassium were small, but there was a tendency for split applications to be superior to late or early applications.The beneficial effect of delayed or split applications of nitrogen was associated with an improvement in the recovery of nitrogen in the crop which was largely ascribed to a reduction in loss due to leaching. Total and tuber dry-matter yields were linearly related to leaf area duration (D) in both crops, although the earlier variety was more efficient per unit of D. High values of L (6) were recorded for both crops, but there was no indication of an optimal value of L; consequently CCC which reduced L also reduced yield. D was closely related to the maximum quantity of nitrogen accumulated in the leaves per unit area of ground.
Phosphorus requirement of the buffalo (Bos bubalis) for maintenance
Authors: Agarwala O. N. , Nath K. , Mahadevan V. 
Published: March 2009

SUMMARYThe phosphorus requirement of the buffalo (Bos bubalis) for maintenance has been determined from the data of two feeding and balance experiments each with twelve animals in randomized block designs and one with six animals using 3x3 latin square designs in duplicate. The level of phosphorus intake was varied by adding appropriate quantities of sodium dihydrogen phosphate in Exp. 1, by adding wheat bran in Exp. 2 and by adding dicalcium phosphate in Exp. 3.Regressions of phosphorus outgo (7) on P intake (X) gave values of 14–7 g/day in Exps. 1 and 2 and 17–2 g/day in Exp. 3. These values can be taken to be estimates of the P requirement of the adult buffalo for maintenance.The initial and final serum inorganic phosphorus in Exp. 1 also indicated that the phosphorus requirement was between 12 and 17 g/day.
Early reproductive failure of ewes in a hot environment V. The conceptus
Authors: Ryle Margaret 
Published: March 2009

1. A balanced factorial experiment was carried out with forty-eight Merino ewes. There were two levels of each of the four factors: environmental temperature, thyroxine status, vitamin A intake and progesterone status. Each ewe was killed at 25 days' pregnancy. The embryos and their membranes were weighed and examined histologically.2. There appeared to be no treatment effects on the embryonic length/weight ratio. The ratio between embryonic weight and ‘conceptus minus fluid’ weight may have been affected. There was no evidence of treatment effects on the degree of differentiation of either the embryo or the chorioallantois.3. Surviving embryos tended to be large where thyroxine was supplied, i.e. where viability was good, and vice versa. Dead embryos fell into two groups: those less than 3 mm. long and those 6 mm. or more which had probably died shortly before the ewes were killed.4. There were no significant correlations between the weights of live embryos and mean rectal temperature, plasma vitamin A concentration or any of the histological indices measured in the endometrium. In the hot-room live embryo weight was correlated with the height of the ewe's bladder epithelium (P < 0·01).5. It is suggested that in the absence of adequate maternal thyroid hormone (i) the trophoblast may enlarge too slowly to stimulate adequately some response in the endometrium essential for maintenance of the embryo, or (ii) disproportionate growth in different parts of the conceptus may result directly in embryonic failure.
Rectal temperature and respiratory rate as indicators of heat tolerance in cattle
Authors: Bianca W. 
Published: March 2009

1. Rectal temperatures and respiratory rates have been determined in four calves during 5 hr. exposures to ten different hot environments in a climatic room.2. Among the various parameters based on rectal temperature response, final rectal temperature proved the best for differentiating between the heat tolerance of individual animals. Under conditions of severe heat, where rectal temperature rose almost linearly with time of exposure, tolerance time proved equally suitable.3. Since initial rectal temperature tended to parallel final rectal temperature, the increase in rectal temperature during exposure did not vary significantly between the animals. Increase in rectal temperature was therefore considered a less suitable measure of heat tolerance.4. Both the lowest and the highest panting rate were associated with a low heat tolerance. From this, as well as from other observations and considerations, it was concluded that respiratory rate, either alone or in combination with rectal temperature, was an inadequate measure of heat tolerance.5. A state of high heat tolerance tended to be associated with only a small loss of body weight during exposure to heat, but showed no relation to body weight itself.6. The order of heat tolerance of the four animals was essentially the same in each of the ten hot environments investigated. It was inferred that within the range of temperatures employed in this study the degree of severity of the heat stress was not an important factor in the discrimination of heat tolerance.
Studies on pigs reared on semi-synthetic diets containing no fat, beef tallow and maize oil: composition of carcass and fatty acid composition of various depot fats
Authors: Leat W. M. F. , Cuthbertson A. , Howard A. N. , Gresham G. A. 
Published: March 2009

1. The object of the experiment was to investigate the detailed carcass composition, and the fatty acid composition of the depot fat, of pigs fed from 10 Ib. to almost 200 lb. live weight on semi-synthetic isocaloric diets containing no fat, saturated fat (beef tallow) and unsaturated fat (maize oil).2. The carcasses of seven litter-mate Large White x Essex hogs, two from each semi-synthetic diet and one from a natural diet were dissected into their individual muscles, bones, fat depots and remainder.
Studies of the Skeleton of the Sheep
Authors: Cresswell E. , Benzie D. , Boyne A. W. 
Published: March 2009

1. After synchronization of oestrus by treatment with progesterone before tupping small groups of ewes were slaughtered at approximately monthly intervals from 5 weeks post-conception to around 3 months post-weaning on two widely differing Scottish hill farms. A few barren ewes were also slaughtered.2. Ash analysis of the 3rd, 4th and 5th cervical vertebrae of the breeding ewes indicated that there was a striking similarity between the flocks in the mean percentage ash values of these bones and also in the decline in these values which occurred between early gestation and 12 weeks after lambing.
Soil water balance and evapotranspiration of irrigated cotton
Authors: Stern W. R. 
Published: March 2009

In a series of five irrigated cotton sowings (T2, T7, T9, T11, T14) evapotranspiration (Et) was determined for the period between October 1961 and October 1962 by observing frequently the changes in soil moisture storage, calculating through drainage, and solving for evapotranspiration in the water balance equation. Thus a water balance was obtained for each sowing extending over the entire crop.The average evapotranspiration in wet season sowings was of the order of 6·5 mm day−1 and in dry season sowings of the order of 4·5 mm day−1. The highest evapotranspiration values ranged between 10 and 12 mm day−1 in T2, T7 and T9 and between 7 and 9·5 mm day−1 in T11 and T14.
Digestibility and chemical composition of fractions of lucerne during spring and summer
Authors: Christian K. R. , Jones D. B. , Freer M. 
Published: March 2009

SUMMARYBulk harvests of primary growth were made at intervals during the spring and summer of 2 consecutive years from an ungrazed area of lucerne (Medicago sativa) and the digestibility by sheep was measured. At the same times, shoots of known length representative of the sward were collected, divided into 7·5 cm lengths, and separated into leaf and stem for the determination of ash, nitrogen, cellulose, and in vitro organic matter digestibility.Digestibility and leaf: stem ratio of the bulk harvests decreased and dry matter increased as the season advanced. Leaf composition changed little, but stem increased in lignin and decreased in ash and in vitro digestibility. In vitro digestibility and leaf: stem ratio were highly correlated with sheep digestibility.Chemical composition of shoots of known heights was similar to that of the bulk harvests. Leaf weights/shoot tended to increase linearly with height of shoot, whereas stem increased nearly as the square of the height. Dry matter of leaf and stem were inversely related to leaf:stem ratio. Stem digestibility decreased with leaf:stem ratio and with increase in shoot height.Chemical components of shoot fractions were associated with each other and were largely dependent on the distance from the top of the shoot at which they had been taken, irrespective of shoot height or time of year. Bottom stems had lower ash, nitrogen and digestibility but higher cellulose, dry weight and dry matter than top stems, whose composition approached that of leaves. Leaf fractions showed little consistent trend with position on the shoot.Some of the difficulties in studying changes in plant composition under field conditions are discussed.
Corolla Tube Length and Nectar Height of Fl Red Clover Plants (Trifolium pratense) and Their Seed Yield Following Honey-Bee Pollination
Authors: Bond D. A. , Fyfe J. L. 
Published: March 2009

SummaryCrosses between nine inbred lines of diploid doublecut red clover were measured for corolla tube length and nectar height, caged with honey-bees, and observations made on the number of bee visits and seed yield. There was evidence of additive genetic variation in nectar height, corolla tube length, bee visits and seed yield. The possibilities for improvement in these characters by selection are discussed. Attention is drawn to a remarkable discriminating behaviour of honey-bees, in that they could apparently recognize plants which had only one parent in common. A cage with a strong colony of honey-bees produced more than twice as much seed as a cage with a weak colony, and plants near to hives gave significantly more seed than plants distant from hives. Plants of English origin tended to have higher and more accessible nectar, more bee visits and greater seed yield than plants of continental origin.
The effect of the size of soil aggregates on nutrient supply
Authors: Cornforth I. S. 
Published: March 2009

SummarySoil aggregates of different sizes, separated by sieving, and artificial aggregates stabilized by a chemical conditioner were used to study the effect of particle size on the uptake of nitrogen and phosphorus by plants growing in pots. Phosphate uptake was consistently less from the coarser than from the finer fractions of soil. The uptake of nitrate was also greater from smaller than from larger aggregates, despite its mobility in soil moisture.
High potassium type red cells in cattle
Authors: Ellory J. C. , Tucker Elizabeth M. 
Published: March 2009

SUMMARYThe distribution of red cell potassium concentrations in ninety–one Jersey cows was examined, and shown to be consistent with two populations, a high (HK) and low (LK) type. In tracer potassium uptake experiments the HK type cells were shown to have a higher active K+uptake, and lower passive K+leak than LK type cells. Tests with the sheep anti–L antibody showed that the L–antigen system, which controls active potassium transport in sheep red cells does not appear to act in cattle red cells.
The reclamation of land covered with pulverized fuel ash. The influence of soil depth on crop performance
Authors: Hodgson D. R. , Holliday R. , Cope F. 
Published: March 2009

1. A review of land restoration problems in relation to the soil depth required for successful crops showed that factual information on this orthodox method of restoration was inadequate.2. A field trial sited on pulverized fuel ash is described in which the relationship between crop yield and soil depth at a range of fertilizer levels was determined; kale, oats, rape, barley and potatoes were the test crops.3. The crops were divided into two groups, sensitive (kale and barley) and tolerant (oats, rape, potatoes) to ash toxicity, on the basis of their response to soil depth at the high fertilizer level. Quadratic expressions relating yield to soil depth, over the range 3–36 in. at each fertilizer level were fitted to the data for each crop group.4. Yield isoquants, derived from the fertilizer response curves at each soil depth, enabled soil depth-fertilizer level combinations to be ascertained for producing a given level of crop yield. Fertilizer could be substituted for soil more effectively for tolerant than sensitive crops.5. A 12 in. cover of soil together with 1½ times the normal farm fertilizer dressing for the crop was the minimum for acceptable yields. Fertilizer use may have to be increased to twice normal dressings to maintain yields if soil depths are reduced to below 12 in.6. Crop yields were not increased by a soil covering greater than 24 in. deep.
A study of food intake and production in grazing ewes II. The interrelationships between food intake and productive output
Authors: Owen J. B. , Ingleton Jean W. 
Published: March 2009

1. Observations were made during the autumn and spring of 1959–60, 1960–61, and 1961–62 on pregnant and lactating Clun ewes of mixed ages grazing under natural conditions. The pattern of food intake during pregnancy and lactation, the output achieved in the form of weight of lambs produced at parturition, milk yield, and bodyweight change of the ewes themselves was investigated. The interrelationships between these factors, as influenced by the feeding of supplementary concentrate, either for 7 weeks before or 7 weeks after lambing, or during both periods, was elucidated.2. Daily dry-matter intake was found to be of the order of 1·5–2·0 kg. for this type of ewe, but there was considerable individual variation (coefficient of variation about 20%). Intake did not increase concurrently with the demands of the foetus during the later stages of pregnancy, and even became depressed as parturition approached. Immediately after lambing there was a spectacular increase in intake, which, after rising to a peak, was maintained at a high level during the lactation. Ewes receiving supplementary concentrates showed an increase in food intake over those unsupplemented, but this increase was less than the amount of dry matter fed in the supplement, even on rather bare pasture.3. During the early stages of pregnancy there was no apparent difference in the weight gains of singleand twin-bearing ewes, but during the last 8 weeks prior to lambing twin-bearing ewes made greater weight gains. In relation to weights taken just after parturition ewes producing twins had lost most weight. Unsupplemented ewes lost more weight than those receiving supplements. Lack of supplementation prior to lambing only limited production in the case of twin-bearing ewes.
131I concentrations in blood, milk, urine and faeces of dairy cows following a single dose of radio-iodine
Authors: Lengemann F. W. 
Published: March 2009

1. The concentrations of 131I in milk, urine, and faeces were compared to the total and non-proteinbound radio-iodine of blood after a single dose of radio-iodine to cows that were being maintained on diets providing about 3·5 or 12-16 mg. of stable iodine per day.2. In general, the 131I concentrations in milk and urine tended to parallel the non-protein-bound 131I of blood. Faecal 131I levels of the low-iodine cows tended to parallel that of the whole blood, whereas it followed the non-bound radio-iodine of blood for cows on the higher stable iodine diet.3. Compartmental analysis of the concentration curves showed a component with a T½ of from 10 to 22 hr. being common to both groups of cows. The second component of the curves constructed for the cows on the higher iodine intake had a T½ of from 41 to 58 hr. The second component for the low-iodine cows had a T½ that ranged from 83 to 169 hr. for the urine, faeces and non-bound radio-iodine of blood and 1200 and 1580 hr., respectively, for the faecal and whole-blood curves.4. A greater proportion of bound radio-iodine was observed in the milk and blood of cows on the low-iodine diet than for the cows on the higher iodine intake. The proportion of bound 131I in blood increased with time, but the bound 131I of milk was relatively constant.
The uptake of magnesium under exhaustive cropping
Authors: Salmon B. C. , Arnold P. W. 
Published: March 2009

1. A range of soils were cropped exhaustively by perennial rye-grass for up to eleven months in the glasshouse; some were also cropped with Dutch white clover.2. At least 100 lb./acre of magnesium was taken up from most soils, and some soils supplied more than 200 lb./acre. The amounts of magnesium taken up decreased with successive harvests, suggesting that the available magnesium was progressively depleted. Although the ‘exhaustion’ magnesium (Mg taken up by crops+residual exchangeable magnesium) was greater than the initial exchangeable magnesium, these two measurements were closely correlated (r = 0·99). If non-exchangeable magnesium was released during cropping, the releases were proportional to the initial exchangeable magnesium contents. However, the exchangeable magnesium measurements may have extracted only a proportion of the magnesium available naturally.3. Any releases of magnesium were small compared with the amounts available from the outset, and the crops obtained magnesium mainly from the exchangeable form. Rye-grass and white clover gave similar results.4. The exchangeable magnesium in some exhausted soils was increased by wetting and drying. This effect may occur in the field, where the magnesium lost in cropping could be replenished by only small releases of non-exchangeable magnesium.
Resistance toSclerotinia trifoliorumin red clover collected from North Africa
Authors: Bond D. A. , Toynbee-Clarke Gillian 
Published: March 2009

Introductions of red clover indigenous to the Atlas mountains of North Africa were shown to have a high degree of resistance toSclerotinia trifoliorumwhen a natural attack occurred in field trials at Cambridge. Differences between the two classes of clover varieties: (1) North African populations, and (2) the British varieties Essex broad red and S. 123, were highly significant for the proportion of row affected, the number of affected areas and the average length of affected area. The North African material is expected to be a useful source of resistance toSclerotinia trifoliorum, in breeding programmes.We are indebted to Mr H. H. Rogers for his guidance and for collecting the red clover plants during the 1962 North African expedition which was supported by the Agricultural Research Council. We also acknowledge valuable criticism of the manuscript and provision of a computer programme by Mr J. L. Fyfe and help with field records by Mr M. Pope and Mrs H. E. Pape.
Some aspects of competition for light in potatoes and sugar beet
Authors: Bremner P. M. , Saeed E. A. K. El , Scott R. K. 
Published: March 2009

1. In experiments on potatoes and sugar beet, interplant competition for light was varied by altering the spacing distance between plants grown in containers, while competition for water and nutrients was eliminated.2. In both experiments the relative growth rate was 10 % less in closely spaced plants because net assimilation rate was greatly decreased; leaf area ratio was increased. Increasing competition for light decreased mineral nutrient uptake.3. It was considered that differences between the treatments in the intensity of competition for light was greater in these experiments than it normally in the field because differences in leaf area index were greater. The leaf area of widely spaced plants was smaller in these experiments than in the field; this was thought to be due to a more limited supply mineral nutrients in the former.4. In both species, the greatest crop growth rates were observed at leaf-area indices well below the maxima attained. The likelihood that observed crop growth rates were near maximal under the prevailing environmental conditions is discussed.