bluuebunny/crossref_metadata_2025 huggingface dataset:
Animal production from rotationally-grazed natural and sown pastures under coconuts at three stocking rates in the Solomon Islands
Authors: Smith M. A. , Whiteman P. C.
Published: March 2009

A continuously grazed trial on natural and sown pastures under coconuts was reported by Watson & Whiteman (1981). This has been continued for another 3 years as a rotationally grazed trial. The paddocks were divided down the centre and three animals grazed for 28 days in one half and were transferred to the other half for 28days. The same three stocking rates of 1·5, 2·5 and 3·5 steers/ha were maintained. In the sown pasture paddocks Brachiaria decumbensand Brachiaria miliiformis were planted in rows from rooted cuttings, while Centrosema pubescens (centro) and Pueraria phaseoloides (puero) were sown, with seed at 4 and 3 kg/ha, respectively. Naturalized pastures were maintained by grazing at 2·5 steers/ha during the establishment of the sown pasture. Light transmission was 62 %. Sown grasses were lost after 4 months from the start of rotational grazing. In the sown pastures puero became dominant. Animal live-weight gain (LWG) on puero was poor in the first 140 days of grazing in each year, but after this time it increased. Centro was the dominant species in the natural pasture of 2·5 and 3·5 steers/ha. However, there was little difference in yearly LWG except in year 3 when the 2·5 steers/ha had higher gains in the natural (363 kg/ha) than in the sown pasture (250 kg/ha). Th9 mean live-weight gain (kg/ha) in the first 2 years of the rotationally grazed trial (315 kg/ha) was lower than in the continuously grazed trial (364 kg/ha) at 3·5 steers/ha. The time and efficiency of collecting fallen coconuts was lower at 1·5 steers/ha in both pastures, but not different between 2·5 and 3·5 steers/ha. In continuous and rotational grazing there is little point in planting Brachiaria species. Productive pastures in plantations oan be obtained by conti oiling weeds and sowing centro and puero into the naturalized Axonopus compressus and stocking at 2–5–3–0 steers/ha. Further research on other grasses such as Ischaemum aristatum and Stenotaphrumsecundatum may lead to better grass persistence.
Working rules for determining the plot size and numbers of plots per block in field experiments
Authors: Lin C. S. , Binns M. R.
Published: March 2009

Working rules for determining plot size and number of plots within a block in field experiments are proposed based on the value of the intrablock correlation (ρ), which can be obtained from the analysis of variance of a randomized-block experiment. The method uses Binns' (1982) equation to relate this correlation to Smith's (1938) empirical law. The rules are: (1) if ρ is greater than 0·5, use an incomplete block design or reduce the plot size in order to increase the number of replications; (2) if ρ is less than 0·1, an increase in plot size is effective; (3) if ρ is between 0·1 and 0·5, an increase in plot size and a decrease in the number of plots per block may be helpful in combination.
Assessing the need of maincrop potatoes for late nitrogen by using isobutylidene di-urea, by injecting trification inhibitors with aqueous N fertilizers and by dividing dressings of ‘Nitro-Chalk’
Authors: Penny A. , Addiscott T. M. , Widdowson F. V.
Published: March 2009

In experiments with maincrop potatoes at Rothamsted in 1976, 1977 and 1978 ‘Nitro-Chalk’ was broadcast, either as a single dressing on the seed bed, or half on the seed bed and half at tuber initiation. Isobutylidene di-urea was broadcast on the seed bed and aqueous ammonia was injected into the seed bed, without a nitrification inhibitor or with either ‘N-Serve’ (nitrapyrin) or sodium trithiocarbonate; all were compared with ‘Nitro-Chalk’ at rates of 200 or 300 kg N/ha. Additionally, single dressings of ‘Nitro-Chalk’ supplied 150, 250, 350 and 400 kg N/ha. In similar experiments at Woburn in 1979 and 1980 aqueous urea replaced aqueous ammonia and the additional amounts of ‘Nitro-Chalk’ (100 and 400 kg N/ha) were tested as both single and divided dressings. Winter wheat was grown in each of the following years to measure residual effects.

Retaining half of the total N dressing of 200 or 300 kg N/ha as ‘Nitro-Chalk’ until tuber initiation improved yields at Rothamsted in 1976 and 1978 when irrigation was applied but not in 1977 when it was not. Dividing the N at Woburn improved yields at 100 and 400 kg N/ha but not at 200 or 300 kg N/ha. At Rothamsted injected aqueous ammonia was on average similar in effect to the undivided ‘Nitro-Chalk’ dressing at 300 kg N/ha, but less effective at 200 kg N/ha. In 1977, the wettest summer, it was, however, the most effective of the N-sources, provided that an inhibitor had been applied with it. At Woburn, injected aqueous urea did not differ consistently in effectiveness from ‘Nitro-Chalk’ and inhibitors did not improve its performance. Isobutylidene di-urea (IBDU) gave the smallest yields at both farms, apparently because it was too slowly available. Tuber size distributions were affected little by the amount or the form of N.

IBDU residues increased wheat yields the most following the potatoes at Rothamsted. This apart, the N-sources had similar residual values.
Soil factors affecting the yield of winter wheat: analysis of results from I.C.I. surveys 1979–80
Authors: Weir A. H. , Rayner J. H. , Catt J. A. , Shipley D. G. , Hollies J. D.
Published: March 2009

The soils of fields where winter wheat yields were measured for the I.C.I. Ten Tonne Club Survey in 1979 and 1980 were identified according to the soil series recognized by the Soil Survey of England and Wales. The yield distributions were almost normal, with means 1·49 and 1·60 t/ha greater than the national average. Soil series accounted for 18–19% of the yield variance in both years, which was much more than any other single factor measured. If introduced in best order, soil series, crop variety, previous crop and sowing date accounted for 31% of the variance in both years. However, classes based on soil particle size and drainage, as derived from series identifications, accounted for very little of the variance. Only thick brickearth (loess) soils gave greater mean yields in both years than the overall means of all sites where series were identified. The same soil types provided 35% of the sites where > 10 t/ha was achieved in either year, though a wide range of soil types gave such large yields.

Yields were greater in 1980 than in 1979 in almost all parts of the country. Although rainfall was only slightly less in the spring and early summer of 1980 than in the same period in 1979, many parts of the country suffered large potential soil moisture deficits in 1980, but these decreased yields slightly on a few series only. Factors other than rainfall used to calculate soil moisture deficits (radiation or wind) probably affected yields much more than rainfall itself.
The relationship between ultrasonic point readings in live cattle and carcass fat cover
Authors: Greathead K. D. , Barker D. J.
Published: March 2009

Four inexperienced operators used a Smith's Essem Metatest ultrasonic grader and a Philips Sonatest instrument to estimate the thickness of tissue overlying the M. longissimus dorsi at three sites over the tenth intercostal space of live steers. They also measured skin fold thickness over the central site using a micrometer. Suprafascial (selvedge) and total carcass fat were measured at corresponding sites on the chilled carcasses.

The residual standard deviations from multiple and simple regressions of suprafascial and total carcass fat thickness on the ultrasonic readings of different operators, using both instruments over the three sites with and without a measurement of skin thickness were compared.

The following conclusions were drawn. Use of a constant distance from the midline of the live animal to locate the site for ultrasonic point measurement would lead to errors in estimating fat thickness at a specific anatomical location. If the edge of the M. 1. dorsi is palpated to locate the measurement site, estimates of carcass fat thickness with a residual standard deviation of 2·5 mm are possible by relatively inexperienced operators using single point reading ultrasonic instruments. Fat deposition between the fascial sheath and the underlying M. 1. dorsi is a source of inaccuracy when estimating carcass fat cover particularly at sites closer to the midline and on fatter animals.

Using the Metatest instrument, fat cover could bo estimated in the live animal with an accuracy similar to that reported by other workers using the Scanogram. Using the Sonatest instrument the estimates were generally slightly less accurate especially at the most lateral site. Inclusion of a measurement of skin thickness gave a very slight but consistent improvement in accuracy of estimation of carcass fat cover.
Comparison of the effects of aqueous and of prilled urea, used alone or with urease or nitrification inhibitors, with those of ‘Nitro-Chalk’ on ryegrass leys
Authors: Rodgers G. A. , Widdowson F. V. , Penny A. , Hewitt M. V.
Published: March 2009

Field experiments on ryegrass leys at Rothamsted in 1981, 1982 and 1983 examined the eifects of injected aqueous urea and of broadcast prilled urea applied alone or with one of several nitrification or urease inhibitors, on yields and N, K, Ca and Mg uptakes. Aqueous urea, prilled urea or ‘Nitro-Chalk’ were applied as single 375 kg N/ha dressings, and prilled urea or ‘Nitro-Chalk’ as three 125 kg N/ha dressings. The nitrification inhibitors etridiazole or nitrapyrin were injected with aqueous urea, but dicyandiamide (DCD) was broadcast with prilled urea. Neither the urease inhibitor hydroquinone nor the nitrification inhibitors slowed the rate of urea hydrolysis. Neither hydroquinone nor DCD diminished volatilization losses of ammonia from broadcast urea which ranged from 8 to 25 kg N/ha; they were less than 4 kg N/ha from injected urea or broadcast ‘Nitro-Chalk’. Nitrapyrin, etridiazole and DCD effectively inhibited nitrification. DCD, and to a lesser extent hydroquinone, increased yields and nitrogen uptakes from a single broadcast application of prilled urea given either in winter or in spring. However, these yields were still smaller than those given by injected urea or by divided dressings of urea, whether or not an inhibitor was used. The inhibitors did not increase yields with divided broadcast dressings of urea, which were slightly smaller than those with equivalent dressings of ‘Nitro-Chalk’. Inhibitors did not consistently increase yield when injected with aqueous urea. Inhibitors applied with injected or broadcast urea slightly increased K uptakes, and slightly decreased Ca and Mg uptakes.
Carbohydrase activity in the pancreatic tissue and small intestine mucosa of sheep fed dried-grass or ground maize-based diets
Authors: Janes A. N. , Weekes T. E. C. , Armstrong D. G.
Published: March 2009

Two groups of six sheep were fed either dried-grass or ground maize-based diets for at least 4 weeks before slaughter. Samples of the small intestinal mucosa and spancreatic tissue were assayed for a-amylase, glucoamylase, maltase and oligo-l,6-glucosidase.

The pancreatic tissue contained high activities of α-amylase and much lower activities of glucoamylase, maltase and oligo-1,6-glucosidase. There was no effect of diet on the specific activities of any of these enzymes in the pancreatic tissue.

The activity of α-amylase adsorbed on to the mucosa of the small intestine was greatest in the proximal region of the small intestine, the activity generally declining with increasing distance away from the pylorus. There was no diet effect on the absorbed α-amylase activity.

Similar patterns of distribution along the small intestine were observed for maltase, glucoamylase and oligo-1,6-glucosidase with the highest activities in t he jejunum. There was no overall effect of diet on glucoamylase or maltase specific activities and glucoamylase total activity, although the total activities of maltase and oligo-1,6-glucosidase were significantly greater for the sheep fed the ground maize-based diet (P < 0·05).

It is suggested that ruminant animals may be capable of digesting large amounts of starch in the small intestine through an adaptation in the activity of the host carbohydrases.
Freezing in oil-seedBrassicaspp.: some factors affecting injury
Authors: Dhawan A. K.
Published: March 2009

Involvement of plant genotype, stage of development of plant and seed, fertilizer and irrigation in frost tolerance of oil-seedBrassicaspp. were examined. The number of apparently frost-killed or undeveloped seeds has been used to assess tolerance. ThreeB. campestrisL. genotypes namely Span, Torch and Bell showed considerable tolerance of frost. Very young and also nearly mature seeds were less affected by freezing than seeds at an intermediate stage of development. The amount of nitrogen fertilizer applied had no effect, but the unirrigated orop was injured by frost more than the irrigated one.
Methods and time of application of labelled nitrogen and phosphorus fertilizers in maize (Zea mays L.) cultivation
Authors: Papanicolaou E. P. , Skarlou V. D. , Nobeli C. , Katranis N. S.
Published: March 2009

In this study two field experiments were conducted on a heavy to medium heavy, calcareous, recent alluvial soil of Central Greece. The main aim of these experiments was to study the effect of the most common nitrogen sources, applied in one or two doses, on maize growth and fertilizer utilization. Foliar application of urea was also a treatment included in these experiments.

Phosphorus alone had no significant effect on maize yield. Nitrogen (various forms), alone or in combination with phosphorus, increased the yield and nitrogen content of maize. Maize yield was not significantly affected by the form of nitrogen or by dividing the application of nitrogen. Foliar applications of urea were as effective as soil applications in increasing maize grain yields.

The percentage of fertilizer nitrogen taken up (utilization coefficient) ranged between ca. 58% for sodium nitrate and ammonium nitrate, and ca. 39% for ammonium sulphate and urea, when the fertilizers were applied about 10 weeks after sowing. Foliar urea was nearly as efficiently utilized as urea applied as a sidedressing. Application of the tested fertilizers before sowing was nearly as efficient as or more efficient than application of the fertilizers as a sidedressing at 70 cm plant height (38 days after sowing). Finally, addition of 120 kg N/ha enhanced the amount of soil nitrogen taken up in the maize crop by 33%.
An example of fractional replication in an experiment on sugar cane manuring
Authors: Chinloy T. , Innes R. F. , Finney D. J.
Published: March 2009

Study of the nutritional requirements of sugar cane on a Jamaican estate necessitated simultaneous experimentation with five manurial factors: sulphate of ammonia, superphosphate, muriate of potash, bagasse, and filter press mud. By adopting a one-third replication of a 35 factorial scheme, each factor could be tested at single and double levels for comparison with the absence of the factor.

The structure and confounding system of the design adopted have been described and the method of computing the analysis of variance has been explained. Fractional replication introduces special problems of interpretation, and this experiment illustrates how they may be resolved. Each fertilizer clearly benefited the crop, and several interactions appeared; some ambiguity of meaning is an inevitable concomitant of fractional replication, so that care was needed in order to assign effects to the right causes. The most clearly marked effects were:

(i) Without phosphate, nitrogen failed to produce any response; where phosphatic manuring was adequate the crop responded well to nitrogen.

(ii) Superphosphate and filter press mud were practically interchangeable as sources of phosphate.

(iii) Bagasse appears to act as a source of potash; the interaction of responses is not very clearly established, but little extra response to artificial potash occurred when bagasse was given.

(iv) No evidence was obtained that the double level of any fertilizer was superior to the single.

There was also a suggestion of a reduced superphosphate response in the presence of bagasse.

If a recommendation on manuring were to be based on this experiment, it would be that a maximum of 3 cwt. sulphate of ammonia per acre be used with either 4 cwt. 18% superphosphate and 1 cwt. muriate of potash per acre or 10 tons filter press mud and 20 tons bagasse per acre. In reality, of course, no attempt ought to be made to determine a general manurial policy from results of a single year of experimentation on plant cane at one place.

The experiment should be regarded rather as typical of what can be done than as a complete investigation of manurial needs.
Ruminal ammonia formation in relation to the protein requirement of sheep: II. Comparison of casein and herring-meal supplements
Authors: Chalmers Margaret I. , Synge R. L. M.
Published: March 2009

1. Herring-meal supplements fed to sheep on a basal diet low in protein were more effective than casein supplements in promoting nitrogen retention and growth.

2. The herring-meal supplements caused less extensive formation of ammonia in the rumen than did the casein supplements. This is considered responsible for the differences found in the value of the proteins.

3. Meat from the sheep fed herring meal was not tainted in flavour.

4. The use of formaldehyde to preserve herring before making them into meal had no deleterious effects when the meal was fed to sheep.
On the use of muzzle prints in the diagnosis of monozygosity of cattle twins
Authors: Wiener G.
Published: March 2009

1. Past work on muzzle patterns of individuals and of twins is reviewed.

2. A technique of obtaining muzzle prints by making plaster casts is described.

3. Using casts, muzzle patterns from one-egg and two-egg twin pairs were scored for similarity on a 1– 5 scale. Patterns of one-egg twins were significantly more similar than those of two-egg twins, and the largest part of the total variance was due to the difference between these two groups. The score distributions for monozygous and dizygous twins did not completely overlap, indicating that muzzle pattern is inherited. However, the extent of overlap observed confines the usefulness of muzzle pattern in twin diagnosis to confirmatory evidence at the extremes of the similarity scale.

4. Parts of the muzzle pattern (central groove, cell length, and cell margins) were judged on an arbitrary scale. Two-egg twins were not found sufficiently less similar than one-egg twins for the characters to be useful in diagnosis. Twins were more alike than random pairs, but significantly so only for central groove and MZ cell length.
Placement of fertilizers for potatoes planted by machines
Authors: Cooke G. W. , Jackson M. V. , Widdowson F. V.
Published: March 2009

A two-row hand-dropping potato planter was modified by adding fertilizer equipment. The machine was used in thirty-three experiments in 1951 and 1952 to plant potatoes from flat land and compare broadcast dressings of granulated compound fertilizer with dressings placed near to the seed.

Fertilizer placed either in one band at the side and below the level of the seed, or in contact with the seed, gave consistently higher yields than broadcast dressings. Broadcast fertilizer gave yields similar to those given by only one-half to two-thirds as much placed fertilizer. On the average of all the experiments, placing fertilizer gave about 1 ton/acre more potatoes than broadcasting. The advantages of placement were greatest when low rates of dressing were used.

Broadcast fertilizer was cultivated deeply into the seed-beds in nineteen experiments in 1952 and gave slightly lower average yields than late dressings broadcast on the seed-beds.

Fertilizer placed in bands on the soil surface immediately in front of the seed-shoes gave yields similar to those given by dressings broadcast over the seed-beds in fourteen experiments in 1951. In average planting conditions fertilizer broadcast on the seed-beds or placed in front of the seed-shoes was thrown to the middle of the ridges and concentrated above the seed.

Fertilizer placed in contact with the seed gave higher average yields than dressings in a sideband at both rates of manuring in the 1951 experiments. In 1952 contact placement was slightly superior to sideband placement at low rates of fertilizer and slightly inferior at high rates. In most experiments in each year emergence was delayed by 10–14 days when the heavy dressing was placed in contact with the seed. Early growth was poor but at most centres the crops recovered later in the season and gave good yields. There is most risk of damage from contact placement on light soils, on badly prepared seed-beds and in dry years. Dressings of 10 to 12 cwt./acre of ordinary-strength compound fertilizers are likely to be quite safe when applied in contact with the seed. If heavier dressings are to be used, part should be applied in contact with the seed and part broadcast, such split applications were satisfactory in experiments in 1951.

Farmers planting even moderate acreages of potatoes by machines will benefit by using a suitable fertilizer attachment. Equipment is needed to place fertilizer at the side of the seed so that heavy dressings can be used to secure maximum yields without risk.
Extracted herbage leaf protein for poultry feeding II. The use of leaf protein in chick rations
Authors: Hughes G. Pearson , Eyles Dudley E.
Published: March 2009

1. Two live-weight gain experiments using dayold chicks are described. A mash containing a basic ration with leaf protein was compared with a control mash containing the basic ration plus fish meal.

2. Details of the source of the leaf protein, its extraction and chemical analysis are given.

3. The composition and analyses of the mashes are recorded, together with their rate of feeding.

4. The live-weight gains at fortnightly intervals are discussed and the results adjusted for sex of chicks, weight at day-old and level of protein in the mash.

5. In the first experiment some of the pullets from each treatment were fed on a commercial growers' ration from 6 weeks old to maturity.

6. The birds on both treatments in the two experiments were equally healthy. The mortality rates were normal. The leaf-protein chicks had deep yellow pigmentation.

7. The results of the experiments are compared. In the first the leaf-protein mash was as valuable as the fish-meal mash; in the second experiment the fish-meal mash proved to be superior.

8. A new method of measuring the biological value of the protein of herbage plants is suggested, using extracted protein fed to chicks or rats.

9. It is concluded that a mash composed of homegrown cereals plus leaf protein with vitamin supplements, a balance of minerals and additional aminoacid if necessary, would be suitable for rearing chicks.
Phosphate response, base saturation and silica relationships in acid soils
Authors: Birch H. F.
Published: March 2009

The inverse relationship described in an earlier publication between phosphate response and the degree of base saturation has been confirmed with three further groups of field experiments. As an alternative to the degree of base saturation soil pH may be employed.

The discrepancies sometimes found with the more acid base-unsaturated soils, between actual phosphate responses and those expected from the degree of base saturation were found to be related to the control yields. In general, the higher the control yield on a distinctly acid soil the more the percentage response to phosphate fell short of that expected, and vice versa. By forming multiple regressions of percentage phosphate response on both control yield and the percentage saturation of the B.E.C. a more accurate assessment of phosphate response is possible than by using the simple regression of response on the percentage saturation of the B.E.C. A measurable soil characteristic that could be used in the multiple regressions instead of the control yield was not found.

Very significant and inverse relationships were established between percentage phosphate response and the amount of water-soluble or citric acidsoluble silica. These silica contents were also found to be significantly and directly related to the percentage saturation of the B.E.C. It appears that measurements of pH, silica and base saturation function similarly in classifying the soils, distinguishing between the almost neutral soils retaining phosphate in an available form associated with exchangeable bases, acid soils with relatively unavailable phosphate associated with iron and aluminium compounds, and soils intermediate between these.
The effect of environmental temperature and humidity on the ear temperatures of Ayrshire calves
Authors: Beakley W. R. , Findlay J. D.
Published: March 2009

1. The surface temperature of the right and left ears of 4-month-old Ayrshire bull calves subjected to temperatures of 15, 20, 25, 30, 35 and 40° C. at a low humidity of 17 mg./l. absolute humidity and to 30, 35 and 40° C. at a high humidity of 7 mg./l. saturation deficit, have been measured in a climatic room.

2. From 20 to 40° C. at both humidities, but excluding 40° C. at high humidity, the ear-surface temperatures behaved exactly as did the mean surface temperature of the trunk as expressed in the relation
The late manuring of winter wheat: an observation on the nutritive value of the grain
Authors: Greer E. N. , Grindley G. G.
Published: March 2009

1. Wheats from manurial trials, whose nitrogen contents differed by reason of the fertilizer treatment applied, have been used as the sole source of protein in rat-feeding experiments.

2. Pairs of rats given such diets have shown increased growth when fed wheat of higher nitrogen content.

3. Measurement of the ratio of growth rate to nitrogen ingested, suggests that the difference obtained is due, not to increase in the acceptability of the diet, but to the greater nutritive value of the grain from the manurial plots.
Studies in selective weed control V. The control of weeds in linseed by chlorinated phenoxyacetic acids
Authors: Holly K. , Blackman G. E.
Published: March 2009

Between 1946 and 1950 multifactorial field experiments were carried out to determine the potentialities and effectiveness of chlorinated phenoxyacetic acids for the selective control of weeds in linseed (oil flax). The initial experiments of 1946 demonstrated that treatment with sodium 2-methyl-4-chlorophenoxyacetate led to considerable increases in the yield of seed through a reduction of the weed population and the consequent decrease in weed competition.

The subsequent experiments were undertaken on relatively weed-free crops so that the direct effects on the crop of compound, formulation, and stage of growth at the time of application could be investigated along with differences in varietal response. Amongst the observations made were time of flowering, straw length, the yield of seed, capsule production, seeds per capsule and the weight, oil content, protein content and germination capacity of the seed.

At similar dosages sodium methylchlorophenoxyacetate is less phytotoxic than sodium 2, 4-dichlorophenoxyacetate while the parent acid and particularly the ethyl ester of the dichloro - compound are much more injurious. With sodium methylchlorophenoxyacetate the tolerance is greatest between the post-cotyledon stage and a height of 20–25 cm.; within this range of plant development dosages up to 3·5 lb./acre have no adverse effects on the yield of seed. Treatment within 2–3 weeks of flowering delays flowering and reduces the seed weight. When dichloro-compounds are employed there are additional effects, such as the formation of abortive capsules or a reduction in the number of seeds per capsule. Under some conditions the oil content and the germination capacity of the seed is depressed but the protein content is increased.
Analysis of plant competition data from an incomplete mixture diallel experiment
Authors: Gleeson A. C. , McGilchrist C. A.
Published: March 2009

An analysis of variance is developed for data from an incomplete mixture diallel experiment, where one subset w of the p genotypes are not grown together in mixtures. Estimation procedures and tests of hypotheses concerning relative yield totals and aggressivities are discussed, and an example is presented.
A comparison of diploid and tetraploid Lolium perenne L. sown alone and in mixtures with particular reference to the effect of treading
Authors: Charles A. H. , Valentine J.
Published: March 2009

Diploid and tetraploid perennial ryegrass (Lolium perenne L.) cultivars were compared sown alone and in mixtures, with and without cattle treading for 4 years after the year of sowing. Data were also obtained on the survival of tetraploid ryegrass in mixtures under farm conditions.

The overall effect of treading was not large but annual yield of dry matter was reduced by cattle treading every year (mean 9%). Sheep grazing and treading also reduced yield below that of cut plots. The reduction depended on the sampling date and varied from 40% to nil. In two instances treading increased yield.

Interactions between cultivars/mixtures and treading occurred in 22% of the occasions when treading influenced yield. In the first harvest year the tetraploid Reveille was more resistant to treading than the diploid S. 24. In older swards (3rd and 4th harvest year) the situation was reversed. The occurrence of cultivar/mixtures × treading interactions and the effect of mixing diploid and tetraploid ryegrass on resistance to treading were unpredictable.

The evidence from the main trial and the farm survey showed that tetraploid ryegrass could persist for at least 3 years after the seeding year when exposed to periods of high stock density. In addition, in mixtures there was no initial domination of the sward by either component when cut or when subjected to severe treading. In the third harvest year of the experiment the proportion of tetraploid ryegrass decreased considerably. Total yield of the mixtures was not significantly different from that of pure swards of the components though seasonal distribution of yield could be modified. The contribution of tetraploid ryegrass to swards up to 4 years old was in proportion to the percentage of tetraploid in the seeds mixture. Evidence from both the experiment and farm survey demonstrates that it is possible to exploit advantages claimed for tetraploids in mixtures for three harvest years without detrimental effect on sward performance.
The seminiferous epithelial cycle and spermatogenesis in goats (Capra hircus)
Authors: Bilaspuri G. S. , Guraya S. S.
Published: March 2009

The development of the acrosomic system and the spermatid nucleus were used to define 14 stages of the seminiferous epithelial cycle in goats; these stages provided a basis for the examination of the behaviour of different spermatogenic cells which gave an idea of the efficiency of spermatogenesis. Eighteen steps of acrosome development (spermiogenesis) were observed in testicular material stained with periodic acid-Schiff. The first 14 steps were used to classify SEC into 14 (I–XIV) stages which in turn were employed to study the pattern of differentiation of spermatogenic cells by counting them in each stage of the cycle. Three generations of type A (A1, A2, A3), one generation of type intermediate (In) and two generations of type B (B1, B2) spermatogonia could be distinguished. A1spermatogonia divided primarily in stages IX–X to produce A2spermatogonia which in turn divided in stages XII–XIII to produce A3spermatogonia and A, spermatogonia. A3spermatogonia divided in stage XIV to produce In spermatogonia whereas A1 spermatogonia did not divide till the next cycle but underwent 26·3 % degeneration. In spermatogonia divided to form B1spermatogonia in stages III–V which further divided to produce B2spermatogonia in stage VI. Types A3, In and B2spermatogonia showed 15·0, 25·0 and 25·8% degeneration respectively. B2spermatogonia divided in stages VII–VIII to produce double the number of primary spermatocytes which persisted without any degeneration till stage XIII of the following cycle and divided at the beginning of stage XIV to form double the number of secondary spermatocytes. These cells divided at the end of stage XIV to form less than double the number of young round spermatids, showing 10·4% degeneration. It is concluded that the development of the acrosomic system as well as the spermatid nucleus could be conveniently used to study the behaviour of spermatogenic cells and that the process of spermatogenesis was less efficient than thought previously.
The functional development of the calf I. Growth of the stomach of the calf
Authors: Godfrey N. W.
Published: March 2009

1. Fifty-four dairy type calves were grazed together on a perennial-type pasture. At regular intervals from birth to 17 weeks individuals were slaughtered and the weights of their reticulorumens, omasums and abomasums were immediately recorded.

2. The recitulo-rumen had the fastest growth rate of the organs of the stomach and the abomasum had the slowest.

3. During the first few weeks after birth, the four stomachs altered rapidly in proportion to the live weight of the calf. By 17 weeks of age, the reticulo-rumen apparently had not reached a constant weight relative to live weight.

4. As a percentage of the total weight of the three organs, the reticulo-rumen reached a relatively constant proportion by about 8 weeks of age.
The effect of restricted access to food on the voluntary food intake of pigs
Authors: Wyllie D. , Owen J. B.
Published: March 2009

Two experiments were carried out to examine the effects of restricted food access on the voluntary food intake of pigs given diets of varying energy content or palatability. Where pigs were offered access to food for a restricted time period each day, the voluntary food intake was reduced in relation to the length of access allowed. Compensation was slow, particularly where a low-energy diet was fed. Younger pigs (35–45 kg) compensated faster than heavier pigs (100–110 kg). The responses of the heavier pigs appeared to be similar to those reported for genetically obese rats in their strong reaction to diets of different energy content or palatability.
Biology of the codling Moth Cydia (Carpocapsa = Laspeyresia) Pomonella L. (Olethreutidae, Lepidoptera) and effect of fruit age on its diapause induction
Authors: El-Gamil F. M. , Gaaboub I. A. , El-Sawaf S. K.
Published: March 2009

The number of generations and the durations of the developmental stages of the codling moth (Cydia pomonella L.) that fed on fresh pear fruits were studied during a whole year, 1973, under laboratory conditions. In the next year, diapause of larvae was investigated in relation to the larval food.

Results showed that this insect reproduced four generations on pear fruits under laboratory conditions and diapaused during the whole period of the autumn. Broods of these generations occurred during April, June, July and September, respectively.

There was a suggestion that the larval food affected the induction of diapause in this insect. About 83% of larvae which fed on ‘ripe native Volos apples’ diapaused as early as the second half of June although the majority of larvae (93%) which fed on ‘immature pears’ continued development to adults and only 7% began to diapause under the same conditions. Up to 98% of larvae which fed on ‘fully mature ripe pears’ did not develop beyond the cocooning stage until the following spring, but 88% of larvae fed on immature pears stored at 4 °C for about 3 months reproduced a new generation about the end of October. These variable results should be attributed to the nourishment on different host-fruits in different maturity stages.
Potassium-releasing power of soils from the Agdell rotation experiment assessed by glasshouse cropping
Authors: Arnold P. W. , Close B. M.
Published: March 2009

1. On cropping Agdell Experiment topsoils to exhaustion with perennial rye-grass in the glasshouse the total K uptakes were directly proportional to the initial exchangeable K contents of the soils.

2. The ability of the Agdell topsoils to release non-exchangeable K under glasshouse conditions decreased in the order: PK-rotation with fallow < NPK rotation with fallow < PK-rotation with clover < NPK-rotation with clover < no-fertilizerrotation with fallow = no-fertilizer rotation with clover.

3. Releases of non-exchangeable K were at least 2·5 times larger than the falls in the exchangeable K for all the Agdell soils.

4. In a ‘take-down’ experiment in the glasshouse on a soil receiving K fertilizer each year in the Saxmundham Rotation I Experiment, loosely held non-exchangeable K was released at a near-linear rate. At least a part of the loosely held non-exchangeable K in the Agdell soils was also released at a near-linear rate.
Studies of the skeleton of the sheep VI. A note on the use of a bone biopsy technique for skeletal studies with sheep
Authors: Duckworth J. , Benzie D. , Cresswell E. , Hill R.
Published: March 2009

The use of a bone biopsy technique for skeletal studies with sheep is described. Histological examination of samples of pelvic bone removed at about mid-lactation from Scottish Blackface ewes grazing on two hill farms revealed little or no evidence of skeletal resorption. This was in agreement with the results of in vivo radiography carried out in this and another field experiment reported as part V of this series (Benzie, Cresswell, Duckworth, Hill and Boyne, 1961).
Studies on copper deficiency and toxicity symptoms in some common crops of Gujarat (India)
Authors: Neelakantan V. , Mehta B. V.
Published: March 2009

1. Symptoms of copper deficiency and toxicity were studied in guar, bottle gourd, eggplant and blue panic grass using sand culture technique.

2. The visual deficiency symptoms are: curling of the young leaves along the margins, chlorosis of the leaflets, necrotic spots on the leaves and drying of very young leaves in guar; loss of turgidity and drooping of lower leaves followed by chlorosis and drying of leaves in bottle gourd; faint green colour of the leaves, chlorosis of the outer rim of the older leaves, white necrotic spots and leaf scorch in eggplant; yellowish green colour of leaves, brownish white spots and depressed growth in blue panic grass.

3. The toxicity symptoms are: stunted growth, drying of the lower leaves and formation of few seedless pods in guar; chlorosis of the lower leaves and marked stunted growth in bottle gourd; dull green colour and chlorosis of the leaves in eggplant; stunted growth, leaf chlorosis and burning appearance of the plant in blue panic grass.

4. There is an increase in copper uptake with increase in the rates of application of copper.

5. There is a decrease in. the molybdenum content with increase in copper applications indicating the inverse copper-molybdenum relationship.
Graded levels of herringmeal to bacon pigs, effect on growth rate, feed efficiency and bacon quality
Authors: Laksesvela B.
Published: March 2009

1. The relationship between the level of feeding herringmeal and its effect on growth rate, feed efficiency and bacon quality has been examined in nine experiments, each consisting of three groups of seven (in one series six pigs). All experiments concerned herringmeal with about 7% petrol ether extracted fat, fed in combination with ground cereal grains and concentrates (Table 2).

2. Seven levels of feeding were tried. In the live weight period 20–30 kg they amounted to 3, 4, 5, 6, 8, 10 and 12%, herringmeal respectively. Later the percentages were successively reduced as follows: in the period 30–50 kg live weight 3/4, in the period 50–65 kg 1/2 and in the period 65–80 1/4 of the original amounts. No herringmeal was fed from 80 to 90 kg when the pigs were slaughtered (Table 1).

3. Increased levels of herringmeal produced increased growth rate and also brought about an increased feed efficiency. Most of the response was obtained with moderate levels, i.e. additions starting with 6–8%. Higher levels exerted more total effect, but these further accelerations progressively lessened. For initial additions of 6% herringmeal the growth rate improved on an average estimated at 8% and the feed efficiency by 5% compared with the performances of the pigs on an all-vegetable control diet, whereas corresponding figures for initial additions of 12% were about 13 and 7, respectively. Lower levels proved of little benefit (Tables 3 and 4 and Figs. 1 and 2). Growth-promoting effect of levels of 6% or more proved significant.
The fleece of the Scottish Blackface sheep II. Variation in fleece components over the body of the sheep
Authors: Doney J. M. , Smith W. F.
Published: March 2009

The variations in fleece components over the body of the Blackface sheep are described. The differences amongst regions are relatively large and highly significant. The structural components—density, fibre type ratio and weight per unit area—are more variable than the fibre characteristics—weight, length and diameter. Fairly regular patterns are found which approximately correspond to those found in other breeds and there is evidence of significant animal by site interaction. It is concluded that neither fixed nor random site sampling can be regarded as ideal but that the best procedure would be single or multiple sampling in the mid-side region.
Studies on calcium and magnesium in the alimentary tract of sheep II. The effect of reducing the acidity of abomasal digestain vitroon the distribution of calcium and magnesium
Authors: Storry J. E.
Published: March 2009

1. Increasing the pH of abomasal contents of the sheepin vitroreduced the concentrations of ultrafilterable calcium and magnesium due to the binding of these ions to suspended material in the digesta. In the presence of this material such binding prevented the precipitation of calcium phosphate and magnesium ammonium phosphate which would otherwise have occurred about pH 6·0. Calcium and magnesium soap formation was eliminated as a possible factor contributing to the reduced concentrations of ultrafilterable calcium and magnesium.

2. At saturation the binding capacity of the material was greater for calcium than magnesium. Although some of the binding sites were common to both ions calcium was more strongly bound. The bound and ultrafilterable forms of both elements were in equilibrium.

3. The significance of these findings is discussed.
The protein-saving action of synthetic lysine and methionine
Authors: Evans R. E.
Published: March 2009

When synthetic amino acids are added to an allvegetable diet the amount of nitrogen eliminated in the urine is reduced and the nitrogen retained as tissue protein is correspondingly increased.

The requirements of the weanling pig for essential amino acids have been critically examined, the work involving both growth trials and nitrogenbalance determinations in the metabolism crates.

The addition of synthetic lysine and methionine to a low-protein vegetable diet had a striking effect on the thriftiness of the pigs. It is possible to secure almost as good growth and economy of food conversion on a cereal diet supplemented with as little as 6 % ex. soya-bean meal, when the amino acids are added in appropriate amounts, as is obtained on a similar diet containing sufficient white-fish meal to support maximum growth
The effect of certain dietary regimes on growth pattern and performance of young Friesian bulls fattened for beef
Authors: Boaz T. G. , Kirk G. , Johnson C. L.
Published: March 2009

Twenty-four Friesian bull calves purchased at 10 weeks old were reared in three groups to slaughter at 420 kg live weight. One group (BB) was fed on a barley-concentrate diet to grow rapidly at 1·41 kg/day, a second (GG) was fed on dried grass cubes to grow slowly at 0·97 kg/day and the other (BG) was fed to grow rapidly to a live weight of 250 kg and thereafter at a slow rate, overall 1–20 kg/day.

Efficiency of food conversion, energetic efficiency and efficiency of dissectible muscle production were best for BB animals, followed by BG and then GG. Changes in carcass composition mainly resulted from differential fat deposition, and bone/ muscle development was allometric in relation to fat-free empty body mass. The development of certain characteristics, the head, depth of forequarter, pelvic length and tibia length followed a time scale and may have reflected the priority for nutrients of some entire male characteristics irrespective of body size.

In addition to being most efficient, the fastest growing bulls yielded carcasses with sufficient fat deposition to meet grading requirements, whereas both the slower growing groups of bulls were penalized in this respect.
The accumulation of lead in soils and herbage at Rothamsted Experimental Station
Authors: Williams Carolyn
Published: March 2009

To measure the accumulation of Pb in an area 42 km from London and within 2 km of the A5, A6 and M1 trunk roads, the Pb contents of topsoils collected from sites at Rothamsted Experimental Station since 1881 have been determined. From 1883 to 1972 the increases ranged from 17 to 46% but because of the variable Pb contents within fields, the absolute rate of accumulation is difficult to determine. The Pb content of herbage harvested twice yearly since 1920 has not increased noticeably.
The estimation of the metabolizable energy of forage from its cell-wall content and digestible cell wall
Authors: Moir K. W.
Published: March 2009

Published data are used in support of a hypothesis that equal amounts of digestible cell walls and digestible non-cell walls do not contribute equally to the energy value of forages. The relationship between the concentration in the organic matter of metabolizable energy (kcal/g organic matter) determined at the maintenance level of feeding, and the percentages of cell wall and digestible cell wall in the forage organic matter is defined by:

This equation derived from published data on 12 grasses appears to be applicable to both grasses and legumes.
Emergence of nine varieties of sunflower (Helianthus annuus L.) in salinized soil cultures
Authors: Karami E.
Published: March 2009

Nine high-oil varieties of sunflower were evaluated for their reactions to salinity during emergence in salinized soil culture ranging from 0 to 12·80 mmhos/cm under controlled temperature of 27±1 °C. The varieties were Louck, Vniimk-8931, Chernianka-66, Record, Armarisky, Peredovik, Orizont, Mhjak and Zarea.

Soil salinity decreased the percentage of emergence in all varieties of sunflower. The rate of decrease in emergence of some varieties was greater than others. Among varieties tested Vniimk-8931 (a tall variety) and Chernianka-66 (a dwarf variety) showed the highest and the lowest tolerance to salinity at 7·60 mmhos/cm, respectively. For electric conductivities above 7·60 mmhos/cm, the nine varieties of sunflower could be classified in three categories. Vniimk-8931, Record, Louck, Peredovik and Armarisky as high salt tolerant, Mhjak and Orizont as medium salt tolerant and Chernianka-66 as low salt tolerant varieties.