bluuebunny/crossref_metadata_2025 huggingface dataset:
White clover investigations
Authors: Zaleski A.
Published: March 2009

The traditional method of producing white clover seed is to grow it in a mixed sward with grass, usually ryegrass. Wild white clover was originally harvested from old permanent pastures, which were heavily grazed, especially in the spring. This system has been perpetuated in the production of white clover seed from leys, and in many areas where sheep and cattle are a major item in the farming enterprise, grazing is an integral part of the system and contributes to the cash return of the ley: seed is not the sole objective. However, the general belief in the advantage of grass companion appears to be so strong that many arable farmers with no livestock produce clover seed from grass/clover swards. No doubt the seed ley on such farms is not only a valuable cash crop but it raises soil fertility and provides an alternative crop in arable rotation. The presence of grass, however, makes the management of successful seed production extremely difficult. Excessive grass growth in spring may result in a serious depression of clover, because of the shading effect produced at certain critical growth stages in the life of the sward.
Seasonal fluctuations in the sexual activity of Awassi, German Mutton Merino, Corriedale, Border-Leicester and Dorset Horn rams:II. Seasonal changes in semen characteristics
Authors: Amir D. , Volcani R.
Published: March 2009

Semen characteristics of local and imported rams were studied over a period of 2 years.

Awassi and Border-Leicester rams with regular Awassi and Border-Leicester rams with regular semen collections throughout the year showed definite seasonal variations in the volume and number of sperms in their ejaculates: maximum levels during the autumn and minimum during the spring months. The sperm density reached its maximum during the spring and its minimum during the autumn as a result of the opposite changes of the semen volume. In the rams without regular semen collections, as those kept in the flock, these seasonal changes were not distinct. In the imported rams from breeds without a
Upgrading the indigenous poultry of Uganda IV. Egg production
Authors: Trail J. C. M.
Published: March 2009

Data on egg production, egg weight, food consumption, broodiness, mortality and body weights of the progeny of indigenous poultry of Uganda crossed with Light Sussex, White Leghorn, Rhode Island Red and Black Australorp breeds were collected collected over the 25-week period from 161 to 336 days of age and compared with the performances of indigenous poultry.

In comparison with the indigenous birds, the cross-breeds had a 61% higher mean egg production rate, a 34% lower food consumption per pound of eggs produced, a 15% higher egg weight, a 30% reduction in mortality, a 23% increase in body weight and a decrease in broodiness.

All the cross-breeds were superior in productive respects to the indigenous birds and the White Leghorn and Light Sussex breeds appeared to be the best for use in the upgrading of indigenous stock for highest egg production results.
The effects of exposure in Blackface sheep with particular reference to the role of the fleece
Authors: Doney J. M.
Published: March 2009

1. The effect of shelter from winter conditions was studied in terms of body-weight change of dry sheep individually fed a maintenance ration. In 2 years, one a mild and the other a hard winter, the exposed group lost weight relative to the sheltered group.

2. Within the treatments attempts were made to relate individual weight loss to a variety of fleece components. These results were not conclusive, but they suggest that such components as depth of wool and weight or volume of wool per unit area of skin have some effect in reducing weight loss under climatic stress conditions.

3. A method of measuring the insulation provided by the fleece in dry environmental conditions was developed. It was shown that exposure to moderate winds increased the heat flow by between three and five times. The results again suggested that significant differences in insulation could be found between sheep within a breed. It was not possible to demonstrate the overwhelming importance of any single fleece component.
Current topics in drought physiology
Authors: Jones H. G. , Corlett J. E.
Published: March 2009

Drought is probably the most important factor limiting crop yields worldwide, therefore it is not surprising that there has been continuing interest in the ways in which drought affects crop yield. Efforts have been concentrated in this area in the hope that it would prove possible to use a knowledge of drought physiology to provide a rational basis for the development of rapid methods of breeding drought tolerant cultivars, and also to help in the improvement of crop management for dry conditions. The last five years have seen some important reassessments of the underlying principles and concepts involved in plant response to drought and these will be outlined in this brief review. Some of these important shifts in emphasis have been highlighted by Kramer (1988), Passioura (1988), Schulzeel al.(1988) and Boyer (1989), particularly in relation to the question of what measure of water stress is most relevant to plant function. As it is not possible to cover all aspects of drought physiology in a brief review of this nature, we highlight four topics where recent findings may have particular relevance to the improvement of drought tolerance in agricultural crops.
Differential response of chickpea (Cicer arietinum)genotypes to salinity
Authors: Dua R. P.
Published: March 2009

Twenty genotypes of chickpea, selected according to their performance in trials conducted during 1988/89 in saline fields having equal concentrations of SO4and Cl, were studied during 1989/90 at Karnal, India. The Cl-dominated soils were divided into microplots with ECe values of 2, 4, 6 and 8 dS/m. Germination, although delayed at ECe 6 and 8 dS/m, was not inhibited up to ECe 8 dS/m. The sensitivity of all genotypes increased with plant growth and greater salinity. Plant growth was most adversely affected by a salinity of ECe 8 dSm. 100-seed weight was less affected by salinity than other yield components, namely, number of pods/plant, number of seeds/plant and seed yield/plant. Chlorides had a more severe toxic effect when present in domination than when they were balanced by an equal concentration of sulphates. Genotypes varied in their tolerance of Cl-dominated salinity. Cultivars ICCC32 and 1CCL86446 showed the most tolerance to Cl-salinity, having > 0·75 Mean Tolerance Index values for all eight characters, followed by ICC5003, ICC10575, ICC12908 and ICC12926. ICC12928 had the highest mean tolerance index value for number of pods/plant and highest threshold value and ICC4953 the highest mean tolerance index for 100-seed weight, indicating their better tolerance at flowering and maturity respectively. Therefore, crossing genotypes of the latter with the former group should produce some recombinants with improved tolerance to salinity at all growth stages and at maturity.
Growth cabinet studies into cold-tolerance of Festuca arundinacea populations: III. Cold tolerance of roots and shoots
Authors: Thomas W. D. , Lazenby Alec
Published: March 2009

Plants of three populations of Festuca arundinacea, syn. 1 and syn. 2 (North African) and S. 170 (British) were subjected to 3 h cold stress treatments in the range 13–25 °F. Such treatments were applied independently to either roots or shoots, the untreated plant portions remaining at 35–40 F°.

In all populations considerable tiller death occurred following exposure of roots to temperatures of 17 °F or below; however at no temperature was there complete killing of tillers. Tiller deaths occurred following shoot exposure to temperatures below 21 °F in syn. 1 and syn. 2, and below 19 °F in S. 170. Universal mortality occurred in all populations after shoot exposure to 13 °F.

The degree of insulation of the root: shoot junctions affected survival of both roots and shoots in all populations. Discrepancies between apparent damage to plant parts following treatment, and subsequent survival, suggested that the ability of plants to replace damaged parts might influence survival.

Conclusions are included from the completed programme of growth cabinet studies on cold tolerance of F. arundinacea populations reported in the present series of papers.
The growth rate of heifers in a dairy herd
Authors: Ridler B. , Broster W. H. , Foot A. S.
Published: March 2009

Growth rates of Shorthorn and Friesian heifer calves from 0 to 6 months of age were studied from live-weight data collected over a 10-year period.

Friesian calves were heavier than Shorthorn. Male calves were heavier than female. Calves born to the first pregnancy were smaller than those born to later ones. Gestation length was 5 days shorter for Friesian than for Shorthorn cows. It tended to be slightly shorter for female than for male calves. Non-foetal loss of weight at calving was greater with male than with female calves.

High-level feeding before calving was associated with heavier calves but the effect was not statistically significant.

Calf birth weight increased by 0·026 lb./lb. increase in post-calving live weight of the dam and by 0·564 lb./day extension of the gestation period.

Growth rate accelerated from birth to 3–4 months of age and then declined slightly. Autumn-born calves grew faster in the first 90 days than springborn calves. Age of dam and level of feeding before calving had no effect on rate of growth of the calf.

For both breeds there were significant negative correlations between birth weight and rate of gain in the first month after birth.
The grazing animal and sward productivity
Authors: Herriott J. B. D. , Wells D. A.
Published: March 2009

1. The results of a trial designed to investigate the effects of sheep excreta on sward growth and yield are described.

2. The quantities of plant nutrients excreted, and their distribution, by the grazing animal are discussed. An assessment is made of the value of excreta to pasture growth in the light of the results gained.

3. Under Boghall conditions, the return of excreta had little affect on sward output, the main effect was for the pasture to become progressively more grass dominant. In general, weather and soil nutrient limitation had a greater effect on nitrogen yields from the swards than did excreta. Recovery of excreta nitrogen would appear to be influenced by rainfall and the age of the sward.

4. On a soil inherently low in available potassium, it was found that this element and nitrogen both affected the pattern of herbage growth and composition when returned in excreta. Phosphorus return by the sheep was, however, of no observable value in either the levels of the element in the soil or in the herbage. It was found that rainfall and the botanical composition influenced the contents of mineral elements in the herbages.

5. Balance studies suggest that sheep grazed in small paddocks need adequate pre-conditioning before being moved into a trial. Only by this means can return of excreta reflect consumption of herbage. The limitations of small-scale animal grazing experiments are discussed.
The nutritive value of grasses grown in Uganda when fed to zebu cattle II. The relation between crude fibre and nitrogen-free extract and other nutrients
Authors: Bredon R. M. , Harker K. W. , Marshall B.
Published: March 2009

The correlation between chemical composition and nutritive value of grass fed to short-horn zebu steers in Uganda was investigated. The following regression equations were calculated from the experimental results and discussed in part I of this paper.

Dig. coef. of C.P. = 100·89 log c.p. – 44·45;

r = 0·9738, P < 0·001.

(For use when fodders of wide range of proteins are compared.)

Dig. coef. of c.p.= 5·14 c.p.;

r – 0·9339, P < 0·001.

(For quick calculation when only approximate figures are required.)

Dig. coef. of c.p. = 9·588 + 4·284 c.p.;

r = 0·9521, P < 0·001.

To be used between 4·5 and 17% of crude protein.)

% c.p. in grass eaten = 1·677 c.p.in

faeces – 6·93; r = 0·958, P < 0·001.

Dig. coef. of d.m. = 41·81 + 1·63 c.p.;

r = 0·9362, P < 0·001.

Dig. coef. of o.m.= 46·05 + 1·4152 c.p.;

r = 0·8851, P < 0·001.

The regression equations calculated from the experimental results in the present paper (part II) are as follows:

Dig. coef. of d.m. = 150·88 – 1·179 (c.f. + n.f.e.);

r = 0·9634, P < 0·001.

Dig. coef. of d.m. = 120·03 – 1·778 c.f.;

r = 0·721, P < 0·01.

Dig. coef. of o.m. = 142·50 – 1·045 (c.f. + n.f.e.);

r = 0·9320, P < 0·001.

t.d.n.= 129·39 – 0·9419 (c.f. + n.f.e.);

r = 0·9288, P < 0·001.

t.d.n. = 7·76 + 0·8192 dig. coef. of d.m.;

r = 0·9886, P < 0·001.

s.e. = 0·9367 dig. coef. of d.m. – 20·15;

r = 0·9832, P < 0·001.

s.e. = 120·80 – 1·104 (c.f. + n.f.e.);

r = 0·9468, P < 0·001.

s.e. = 99·44 – 1·868 c.f.

r = 0·7948, P < 0·01.
Bacteria of the ovine rumen II. The functional groups fermenting carbohydrates and lactate on a diet of lucerne (Medicago sativa) hay
Authors: Kistner A. , Gouws L. , Gilchrist F. M. C.
Published: March 2009

1. The composition of the bacterial populations of the rumen of three sheep on lucerne hay was very similar with regard to both the levels of the functional groups which ferment cellulose, starch, glucose and xylose and to the morphological types of which they were composed. The lactate-utilizing bacteria showed more variation in numbers between individual animals.

2. The rumen flora of lucerne hay fed sheep differed from that of sheep on teff hay not only in significantly higher counts of the carbohydratefermenting bacteria in the former group, but also in distinctive types of cellulolytic bacteria.

3. The short- and long-term variations in number of cellulose digesters found earlier in a sheep on a practical diet of lucerne hay were not markedly reduced by feeding the same animal lucerne hay of constant composition.

4. A correlation appeared to exist between the protein content of the lucerne hay and the level of the lactate-fermenting bacteria in the rumen.

5. The changes in the viable counts of the bacteria capable of fermenting cellulose, starch, glucose and lactate during the first 8 hr. after feeding a ration of lucerne hay were small compared with thein vitrorate of multiplication of a pure strain of cellulolytic cocci isolated from a sheep on the same diet. This is regarded as further evidence in favour of the notion that the rumen contents, particularly of animals on high roughage diets, approximates to a continuous culture system.
Effect of Subclinical Helminthosis on nitrogen metobolism in beef cattle
Authors: Vercoe J. E. , Springell P. H.
Published: March 2009

The differential effect of subclinical helminthosis on digestion and nitrogen metabolism in 1-year-old Brahman x Hereford/Shorthorn cross and British (Hereford/Shorthorn cross) steers was investigated.

When helminths were present, the British steers had lower digestibilities of dry matter and nitrogen, lower nitrogen balances, and higher dialysable faecal nitrogen, than had the Brahman cross steers. There were no breed differences in plasma gastrointestinal leakage (estimated by Cr labelling of plasma proteins), plasma content, total plasma protein, plasma protein half-life or plasma urea.

When helminths were eliminated, plasma gastrointestinal leakage was reduced, and plasma content and total plasma protein were increased. These changes were relatively larger in the British steers. The Brahman crosses had lower plasma protein concentrations and higher plasma urea concentrations than the British steers. Plasma protein half-life was unaffected by parasites.

The breed difference in the haematocrit was not affected by the presence or absence of helminths.
Variation in the time of parturition of Merino and Dorset Horn ewes
Authors: George J. M.
Published: March 2009

In a comparison involving 1467 births significantly more Dorset Horn than Merino ewes lambed during the period 08.00–18.00 h. The distribution of lambing during the day differed significantly between breeds. The daytime patterns averaged over breeds, and differences between breeds in patterns, did not change from year to year. At winter and spring lambings, 37% of Merino and 62% of Dorset Horn ewes lambed during the day (08.00–18.00 h) while during summer the corresponding percentages were 23 and 39.

For both breeds, the percentages of primiparous and multiparous ewes lambing during the day period were approximately the same. For Dorset Horns, the proportions of single and multiple births occurring during the day were similar.
The effect on the reproductive performance of sows of dietary protein concentration and pattern of feeding in pregnancy
Authors: Pike I. H. , Boaz T. G.
Published: March 2009

In a factorial experiment the effect of two protein intakes and three patterns of feeding in the second pregnancy of 48 Large White x Wessex Saddleback sows was examined. The high protein (HP) diet (19·5% crude protein) contained 15% white fish meal. The low protein (LP) diet (10·5% crude protein) contained cereal protein only. Nutrient components of the diets differed in protein only. The pattern treatments involved allowances of 1·8 kg (L), 2·7 kg (C) and 3·6 kg (H) per day, the three pregnancy patterns being HL, C and LH with the changeovers made from the 49th to the 63rd day post coitum (p.c). Sows on the three pattern treatments received the same total amount of feed from 0–112 days p.c. and were treated alike at farrowing and during lactation.

Fertility and parturition results were similar for all treatments, but the number of piglets alive after birth (when weighed) was least for LP sows on the HL pattern. At 3 weeks of age the size and weight of litters on HP sows were significantly greater than those on LP sows (P < 0·05 and < 0·001 respectively). More piglets were weaned by HP sows than LP sows (P < 0·05). HP sows gained more weight in pregnancy (P < 0·001) which was slightly longer, and lost more weight in lactation (P < 0·05) than LP sows.

The HL pattern of feeding was associated with smaller live weight gains in pregnancy than the LH pattern (P < 0·001) and the total birth weight of HL litters was lighter than LH (P < 0·05), mean piglet weights being similar. Lactation performance was unaffected by pattern treatment.

The main conclusion is that a low intake, particularly during the latter half of pregnancy, of protein which is of vegetable origin, is associated with decreased viability of the piglets at birth and in early suckling life, and with lower capacity of the sows for milk production.
Semen characteristics of Awassi rams
Authors: Juma K. H. , Dessouky F.
Published: March 2009

On the College of Agriculture farm in Abu-Ghraib 147 ejaculates were collected from three docked and four normal Awassi rams born during November 1962. The work covered a period from 1 April 1967 to 31 March 1968.

Nine semen characters, namely, volume, mass activity, individual motility, sperm concentration, sperm number, pH, methylene blue reduction time and the percentages of abnormal and dead sperms, were studied. The effect of season and docking on these characters was investigated.

Seasonal variation was observed in all traits studied. On the whole, semen quality was poorest during winter and best during summer. The effect of docking was more pronounced on sperm concentration, sperm number and percentage of abnormal sperms. Docking appeared to increase sperm production and reduce sperm abnormality.
Experiments in selecting for resistance to downy mildew in sugar beet
Authors: Russell G. E.
Published: March 2009

In tests with seedlings in the glasshouse, significant differences in susceptibility to downy mildew, caused by Peronospora farinosa f. sp. betae, were observed between individual stocks of sugar beet. The resistance of a particular stock in glasshouse tests was not always a reliable guide to its resistance in the field. There were also serious discrepancies between the results of tests with seedlings and those with mature plants in the field, suggesting that the resistance of certain stocks, relative to one another, may vary with increasing age of the host plant. This contention was supported by evidence from a field experiment in which the susceptibility of several sugar-beet stocks was compared throughout the growing season. It also appears that changes in environmental conditions affected resistance to downy mildew more in some stocks than in others.

Progenies of selected plants that had not shown severe symptoms of downy mildew, after exposure to natural inoculation with P. farinosafor more than 3 months in the field, were much more resistant than the parent stocks. This showed that a single generation of selection under suitable conditions can significantly improve the resistance of sugar-beet breeding stocks to downy mildew.

An inbred sugar-beet line of American origin showed exceptional resistance to downy mildew in experiments under glass and in the field. Inoculated plants of this line usually showed no symptoms of the disease and P. farinosa did not produce conidia on them. These results show that sources of extreme resistance are present in cultivated sugar beet and suggest that an excellent control of downy mildew in Britain may eventually be achieved through the use of resistant varieties.
Differences amongst breeds of sheep in food requirements for maintenance and live-weight change
Authors: Doney J. M. , Russel A. J. F.
Published: March 2009

In a series of experiments, each of 6 weeks' duration, non-pregnant Romney, Scottish Blackface and Tasmanian fine-wool Merino ewes were individually penned in an outdoor environment and allocated a constant ration within a range from 8 to 30 g of a standard dried-grass pellet per kg live weight. Maintenance requirements were calculated from the regression of live-weight change per unit weight on intake per unit weight. Comparable values for the three breeds were computed as 8·4, 9·2 and 14·0 g DOM (digestible organic matter)/kg/day for Romney, Blackface and Merino respectively, the latter being significantly higher than for the two British breeds. Estimates of requirements per unit change in live weight, after allowing for maintenance, were 5·1, 4·6 and 3·0 g DOM/g live-weight change for the three breeds. Methods of estimation of energy requirements and the reasons for differences between breeds are discussed.
Availability of phosphate as affected by duration of fertilizer contact with soil
Authors: Devine J. R. , Gunary D. , Larsen S.
Published: March 2009

The changes in phosphate availability that occurred when fertilizer phosphate was incorporated in moist uncropped soil were examined by storing fertilized soil in the open for periods up to 3 years before a final test crop was grown. Superphosphate was the standard source as it was fully available initially and therefore provided a measure of the rate of immobilization of phosphate on the four soils used. The extent to which this rate was modified by slower rates of dissolution of non-water-soluble sources was examined, using dicalcium phosphate (powder and granular), basic slag and ground North African rock phosphate (GNAP).

Powdered dicalcium phosphate and basic slag in general behaved similarly to superphosphate, indicating very rapid dissolution. The only exception was a slightly lower rate of dissolution of slag on the calcareous soil. Other than in the very acid soil, the rate of dissolution of GNAP was slow so that the available phosphate was not similar to the superphosphate treatment until after at least the second year. On the calcareous soil GNAP was practically inert. Granular dicalcium phosphate was the only consistent slow-release source. It gave available phosphate levels which were initially lower, but subsequently higher, than those from superphosphate. In the absence of a crop, cumulative assessments of phosphate availability were not possible.

The pertinence of these results to the problem of maintaining a high soil phosphate status is discussed.
Nitrate nitrogen in leaves and petioles of sugar beet in relation to yield of sugar and juice purity
Authors: Last P. J. , Tinker P. B. H.
Published: March 2009

The use of the correct N dressing for beet is important, as any excess decreases juice purity and profit, and may decrease sugar yield, but no analytical method will at present predict the best dressing in any particular field. The concentration of nitrate in leaves and petioles of beet was determined to test if it would determine the need for top-dressings of N. Beet on seventeen field trials in 3 years testing N were sampled. Nitrate in a wet tissue extract was determined by reducing to ammonia with titanous sulphate and subsequent distillation.

The petiole nitrate concentration decreased sharply with time, from around 1000 ppm in wet tissue in early June to less than 100 ppm in early September. The nitrate concentrations were closely related to nitrogen dressing, and the rapid decline in concentration was decreased by top-dressings. Comparison of samples taken in June showed that most of the variation between the experiments could be accounted for by the different ages of the plants. Sodium fertilizer had no effect on nitrate content.

Petiole nitrate was inversely related to juice purity and sugar concentration, especially when the nitrate content exceeded 700 ppm in June.

On average, petiole nitrate concentrations about 800 ppm in June were associated with the largest sugar yields, but the content could not be used to predict nitrogen top-dressing requirement accurately at individual sites.

Measuring NO3-N cannot at present be recommended as a method for deciding how much nitrogen fertilizer to use, but it has value for detecting severe deficiencies and in research.
Yield and quality components in maize grown for silage
Authors: Thomson A. J. , Rogers H. H.
Published: March 2009

Results from three trials are presented. The main variables were date of harvest, plant density and variety. Measurements were made of whole-crop yields and yields from plant fractions (leaf, stem, cob). Quality components—digestibility, acid-pepsin solubility, water-soluble carbohydrates, nitrogen and ash—were estimated for whole crop and fractions. There were successive samplings for quality components.

Whole-crop yield from fractions and yield of quality components increased with density. Whole-crop yield differed significantly with harvesting date as did all fractions except cob, although the proportion of cob increased with time. The earlier harvesting date gave greater yields of quality components.

There was no effect of density on the dry-matter content but later harvesting resulted in higher dry matter.

The only quality component affected by density was nitrogen content but there were large effects of harvesting date on digestibility and the acid-pepsin components.

Regressions were computed for quality components on dry-matter proportion of cob and the dry-matter content of the whole crop. Regressions were significant for the acid-pepsin soluble components and the water-soluble carbohydrate component on the proportion of cob. Regressions of digestibility and pepsin-soluble components (total and organic) on dry-matter content were significant.

The implications of these findings to the breeding of maize varieties are discussed.
The influence of density and nitrogen in seed production stands of S48 timothy (Phleum pratense L.) and S215 meadow fescue (Festuca pratensis L.)
Authors: Lambert D. A.
Published: March 2009

Seed production stands of S 48 timothy and S 215 meadow fescue were obtained with varying plant densities by utilizing two driE widths, removing sections of drill, or oversowing drilled material.

Annual tiller counts were made in preselected quadrats, and performances of tiller populations were assessed from these quadrats.
Genetic control of blood potassium concentration in Welsh Mountain sheep
Authors: Khattab A. G. H. , Watson J. H. , Axford R. F. E.
Published: March 2009

The distribution of whole blood potassium concentration in 1783 Welsh Mountain sheep shows marked bimodality, varying about two modes, of 44 and 14 m-equiv./l.

The difference between high (HK) and low (LK) potassium types was not clear-cut. About 5 % of animals lay in the area where the tails of the two distributions merge.

Haematocrit values and plasma potassium concentrations were used to estimate erythrocyte potassium levels. They confirmed that the bimodality is due to variation within erythrocytes but did not offer a satisfactory method of allocating intermediate animals.
Supplementing high-yielding cows at pasture with concentrates fed at a level determined by milk yield and season
Authors: Laird R. , Walker-Love J.
Published: March 2009

The practice of supplementary feeding of concentrates has been the subject of much investigation and also the centre of considerable controversy during the last decade. The latter is perhaps not hard to explain as so many variables are present; first and foremost there is the cow which at all times must be considered an individual whether it be milk yield, time of calving or dry-matter intake. In addition, one must always take into account the quantity and quality of grass, both of which are dependent on sward management and the system of grazing.
Variation in the mineral and crude-protein content of pastures at Muguga in the Kenya highlands
Authors: Howard D. A. , Burdin M. L. , Lampkin G. H.
Published: March 2009

1. Variations in the crude-protein and mineral content of pastures at Muguga are described.

2. At all times sodium appeared to be inadequate, and during dry periods phosphorus and crude protein were also apparently deficient.

3. Except for sodium and calcium, the amounts present of all substances determined largely depended upon the amount of recent rain.

4. The difficulties of interpreting such data have been considered.
Variation in efficiency of food utilization in twin calves II. The effect of live weight and feeding rate
Authors: Taylor C. S. , Young G. B.
Published: March 2009

The relationship of efficiency to weight and feeding rate has been studied in 38 twin calves from 2 to 18 weeks of age. Following birth or weaning heavier animals were more efficient, but tended to be slightly less efficient when fully established on a diet. On balance, they possessed an advantage.

Heavier twins and heavier pairs were also on average more efficient. The increase in mean efficiency for contemporary animals was about 1% for each 1 lb. superiority in weight over the 4-month period. These results contrast with the well-known decline in efficiency as animals increase in weight. Different pairs declined in efficiency with increasing live weight at distinctly different rates judged by the resemblance of twin and co-twin, but evidence for genetic control was slight.

More efficient animals were associated with a relatively more rapid decline in efficiency, leading to a general convergence in efficiency as animals grew heavier.

The relationship of efficiency to feeding rate was very similar to the relationship with weight.
Field experiments comparing the effects of muriate and sulphate of potash on potato yield and quality
Authors: Dickins J. C. , Harrap F. E. G. , Holmes M. R. J.
Published: March 2009

1. Between 1955 and 1961 nineteen experiments were carried out on Majestic potatoes in various parts of England comparing muriate and sulphate of potash at three rates of application, in the range 75–336 lb./acre of K2O. Most of the experiments were on light soils.

2. Total yield of tubers was on average the same from both sources at all rates of application, and this similarity was not affected by environmental conditions.

3. Muriate of potash consistently gave a higher yield of large tubers than sulphate, with an average difference of 0·6 ton/acre. Conversely, muriate gave a lower yield of medium tubers than sulphate, again with a mean difference of 0·6 ton/acre.

4. Muriate of potash significantly depressed tuber dry-matter content in eleven of the experiments, particularly at the higher rates, while sulphate had this effect in three experiments. Muriate gave a small increment in two experiments, at low rates only, while sulphate had this effect in five, most markedly at low rates. Sulphate gave a higher dry-matter content than muriate in most of the experiments. The mean difference was 1·0% at 300 and 336 lb./acre of K2O and 0·4 to 0·5% at lower rates.

5. Sulphate of potash gave a more floury texture to the boiled tubers than muriate in three experiments, but otherwise no difference in texture was detected between the sources.

6. The degree of off-flavour was not appreciably affected by rate or source of applied potash.

7. After-cooking blackening was more marked at low than at high rates of applied potash in seven of the nineteen experiments. Muriate and sulphate of potash had similar effects.

8. Farmyard manure ploughed down in winter was tested in three experiments and did not influence to any important extent the relative effects of muriate and sulphate of potash on tuber yield and quality.

9. Application of the two sources on the flat before ridging and in the open drills was compared in the same three experiments, but did not alter the relative effects of the sources on yield or dry-matter content.
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

The 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

The 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.
The effects of changes in soil compaction and porosity on germination, establishment and yield of barley and globe beet
Authors: Kubota T. , Williams R. J. B.
Published: March 2009

Two degrees of compaction, 'heavy' with a flattyred vehicle wheel, and 'light' with a ring roller, were given to the seed beds after sowing barley and globe beet on three contrasted soils. Changes in pore space of the soils and the responses of the crop to the changed physical properties were measured. The sites used were: Barnfield at Rothamsted, a heavy clay loam long under arable cultivation and having little organic matter; Pastures Field at Rothamsted, a field of silty clay loam ploughed after an 8-year ley; Stackyard field at Woburn, a light sandy loam long in arable cultivation and containing little organic matter.
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.
The effect of Seed rate and growing season on four oat cultivars: I. Grain Yield And its Components
Authors: Jones I. T. , Hayes J. D.
Published: March 2009

1. The effect of seed rate on yield of grain and its components in four contrasting oat cultivars, Maldwyn, Milford, Victory and Marvellous, was investigated over 3 years. At the high (206 lb/acre) and medium (137 lb/acre) seed rates, the final grain yield was similar within each of the three seasons. The low seed rate (69 lb/acre) gave significantly lower yields than the medium or high rates in 1955 and 1957, and in the latter year there was a significant cultivar × seed rate interaction.
Effects of varying variety and spacing on yeids and composition of mixtures of lucerne and tall fescue
Authors: Fyfe J. L. , Rogers H. H.
Published: March 2009

1. In a 3 x 3 x 3 factorial experiment of two replications, with three-factor interactions partly confounded with block effects, the effects of lucerne variety (du Puits or one of two Institute synthetics), tall fescue variety (S.170 or one of two Institute bulks) and spacing (mixed drills 6 in. apart, alternate grass and lucerne drills 6 in. or 12 in. apart) and their two-factor interactions were studied on yield of dry matter and proportion of lucerne. Data are reported for the total of fourteen cuts, for the annual total for three harvest years and for spring, summer and autumn cuts.