bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in growth rate and morphology of perennial ryegrass swards at high and low nitrogen levels
Authors: Davies Alison
Published: March 2009

The nitrogen requirements for maximum production of perennial ryegrass swards in August/September were shown to be of the order of 4 kg N/ha/day. Further increases above this level had no appreciable effect on dry-matter production, leaf area or light intercepted, but maximum tiller numbers were considerably enhanced. Shortage of nitrogenous fertilizer had comparatively little effect on crop growth rate in the early stages of regrowth, but thereafter caused the rate to fall increasingly short of potential. At high fertilizer levels crop growth rate based on total above-ground parts was linearly related to percentage light intercepted in the first month after defoliation, but values subsequently became erratic and at times negative. This change in crop growth rate and the resulting halt in effective net dry-matter production could be associated with the overall pattern of leaf and tiller formation and death, maximum net yield being achieved at the point in time when three new leaves had been produced on each tiller since cutting. It is concluded that in August and September worth-while increases in harvestable net dry matter are unlikely to occur after this stage has been reached, and that managements based on the maintenance of a complete crop cover are not likely to be successful at this time of year.
The food value of beef from steers and heifers, and its relation to dressing-out percentage
Authors: Callow E. H.
Published: March 2009

1. An investigation has been carried out on the food value of beef from steers and heifers. A very varied group was used, selected as being representative of the beef animals slaughtered in England in war time. The animals were from five breeds; ages varied from 1 to over 4 years, live weights from 6½ to 14 cwt. and dressing-out percentages from 50 to 62.

2. The chemical composition of the beef varied widely. The fat from the edible meat, expressed as a percentage of the live weight, varied from 4·6 to 21·6 %, the protein from 6·1 to 7·4%, and the water from 22·8 to 27·4%. The ratio of fat to protein in the edible meat varied from 0·7: 1 to 3·4: 1.
Studies in the absorption and excretion of certain minerals by poultry. II. Changes in the composition of food material as it moves along the alimentary tract of the hen
Authors: Tyler Cyril
Published: March 2009

1. One laying and one non-laying bird were fed a normal calcium ration, and one laying and one non-laying bird were fed a low calcium ration. Four hours after feeding the birds were killed, and the contents of the various portions of the alimentary tract were analysed and compared with the composition of the original food.

2. ThepH of the crop contents is influenced by thepH of the food. The lowestpH value is given by the gizzard contents, but after that there is a gradual rise, until, by the time the 4th segment of the small intestine is reached, thepH. is almost constant at about 6·8 for all birds.
Chick rearing. IX. Studies on the storage of vitamin A and carotenoid pigments by chicks from birth to six weeks, using cyclized vitamin A, vitamin-A alcohol, vitamin-A ester (cod-liver oil) and the pigments of green food and maize as criteria
Authors: Barton Mann T.
Published: March 2009

Studies on the feeding of cyclized vitamin A, vitamin-A alcohol, and vitamin-A ester (as cod-liver oil) to chicks receiving a diet ofc. 13% protein content, show that chicks do not assimilate cyclized vitamin A and only begin to assimilate vitamin-A alcohol and vitamin-A ester between the 35th and 42nd day, when the results of analytical methods employed to evaluate carcass and liver stores of these substances are used as criteria, or when growth is used as criterion.

Studies on the feeding of green food and yellow maize, as sources of provitamin A, and vitamin-A alcohol, to chicks receiving a diet ofc. 17% protein content, show that chicks do not utilize these substances until between the 35th and 42nd day, when the results of analytical methods are employed as criteria of assessment of vitamin A storage in carcass and liver, or when growth is used as criterion.
The response of skin and wool growth to local subdermal temperature changes in a sheep
Authors: Jolly M. , Lyne A. G.
Published: March 2009

Heat-exchange chambers, one for heating and one for cooling, were surgically embedded beneath the skin of a sheep. The intensity of heating and cooling was progressively increased, producing average subdermal temperatures up to 50·3 °C over one chamber and down to 21·0 °C over the other. The normal subdermal temperature was 37·7 °C.

Moderate heating produced a small increase in the length growth rate of wool over the hot chamber. Higher temperatures caused a marked reduction and with still further heating there was almost complete cessation of wool growth.

In contrast to heating, cooling always caused a suppression of wool growth which became more pronounced as the degree of cooling was intensified. The length growth rate decreased to half of normal at one stage but it never ceased.

There was evidence of a slight but progressive decrease in fibre diameter with increasing subdermal temperatures up to 45 °C but at a temperature of 48 °C many of the fibres exhibited a marked thickening. Cooling the skin had little effect on fibre diameter. Pigmentation of the fibres was unchanged throughout the whole range of temperatures used and there was no evidence of change in crimping of the fibres.

Heating in the range 45–50 °C produced an increase in epidermal thickness. Sweat and sebaceous glands, and erector muscles appeared unchanged after heating or cooling but innervation of the skin appeared to be reduced by extreme heating.

The skin and wool growth over a dummy chamber were normal and similar in all respects to that in other control areas.
The effect of soil pH on potassium intensity and release of non-exchangeable potassium to ryegrass
Authors: Islam A. , Bolton J.
Published: March 2009

Ryegrass was used to remove potassium from two acid soils limed to different pH values. Most non-exchangeable potassium was removed from the unlimed soils (pH 4·5) but differences in removal between pH 5·5 and 7·0 were small. Air-drying the soils after cropping released further potassium into the exchangeable form in amounts independent of soil pH.

Equilibrium potassium activity ratios (ARK) after each out declined to small constant values characteristic of the soils. A sandy soil (Woburn) initially contained less exchangeable potassium than a soil with more clay (Sawyers), but after a few crops, ARK, % K in the grass and K uptakes per cut were larger from Woburn soil, showing that non-exchangeable potassium was being released faster than in the other soil.
Effect of ambient temperature and daylength on hoof growth in sheep
Authors: Wheeler J. L. , Bennett J. W. , Hutchinson J. C. D.
Published: March 2009

In Southdown sheep, which grazed and were fed during the day to maintain body weight and were housed at night, there was no clear effect of ambient temperature on hoof growth. In these sheep, equatorial or reversed photoperiods did not influence hoof growth.

In an indoor experiment over 19 months on Merino sheep, with natural light and temperature, fleece accumulated normally between spring shearings. Hoof growth in winter was low at a low level of nutrition but was not reduced in sheep at a higher nutritional level. It fell dramatically at both levels of nutrition in the first month after shearing.

Hoof growth was measured in Merino and Southdown sheep exposed to equatorial daylength in two climate-room experiments in which ambient temperature was varied. Fleece length was kept short and nearly constant by clipping. Hoof growth was greatly reduced by low temperature. At a given ambient temperature it was more rapid when ambient temperature was rising from month to month than when it was falling. The low hoof growth observed in the cold was associated with low hoof temperature and there was some evidence suggestive of reduced blood flow to the skin of the lower legs.

These temperature effects would complicate the use of hoof growth as an index of nutrition.
The growth and performance of rain-grown cotton in a tropical upland environment: II. The relationship between yield and growth
Authors: Hearn A. B.
Published: March 2009

An hypothesis, based on Mason's nutritional theory of boll shedding, was set up to relate the yield of cotton to crop growth in three agronomic experiments. It was postulated that bolls were set only if the demand for carbohydrates of the metabolic sink which they formed did not exceed the supply, both of which were estimated. Two components of the sink were recognized — the daily growth rate of a single boll, DGRB, and the number of bolls on the crop plants. The effects of genotype and environment on these components were analysed. Their product gave the size of the boll sink, CB, which was compared with the crop growth rate, C, to indicate respectively carbohydrate demand and supply. Three sets of evidence to support the hypothesis were considered: (i) when CB > C, the number of bolls, and hence the size of the sink, ceased to increase, and bolls started to shed heavily; (ii) a model to predict yield, based on the hypothesis, accounted for all non-random variation in yield between sowing dates and varieties; (iii) the correlation between yield and various crop attributes, recorded before picking, became strikingly closer between 110 and 130 days from sowing when CB > C, suggesting that yield was determined during that period of time. The network of relationships, studied in these papers in order to relate the yield of a cotton crop to its environment and genotype through their effect on its growth, indicates the form of a dynamic model to simulate growth and predict yields.
Ryegrass populations from intensively managed leys:I. Seedling and spaced plant characters
Authors: Charles A. H.
Published: March 2009

Seed of Lolium perenne L. was grown from material collected from three S.23 leys and one S.24 ley that had been subjected to high rates of stocking and nitrogen application. Comparisons were made between plants grown from seed derived from the leys and from breeders' seed of S.23 and S.24.

Seedling characters indicated that the populations derived from leys differed from each other and from the plants grown from breeders' seed. In S.23 populations the main change occurring in intensively grazed leys was towards higher tillering prostrate seedlings. This did not occur in the S.24, but here the survivor population had a slightly shorter fifth leaf and a lower number of leaves on the main tiller of the seedlings.

As spaced plants, the population derived from the S.23 ley, with the highest percentage ryegrass and the reputation for the highest yields on the farm, gave a higher yield, recorded in three cuts in the first year and in four cuts in the second year, than any other populations. Small differences between S.23 populations in aftermath heading, reaction to rust, and mean date of panicle emergence were recorded. Variance of spaced plant yield decreased in ryegrass derived from older S.23 leys. The S.24 ‘survivor’ population was much later in mean date of panicle emergence than S.24 grown from breeders' seed.
Results from experiments with winter wheat, spring barley and grass, comparing a liquid N-fertilizer either alone or with added herbicide, and top-dressings of ‘Nitro-Chalk’ without or with herbicide sprayed alone
Authors: Penny A. , Freeman S. C. R.
Published: March 2009

During 1970–3 three experiments with winter wheat, three with spring barley, two with permanent grass and one with perennial ryegrass measured the effects of a liquid N-fertilizer (26% N) sprayed over the leaves either alone or with a herbicide added to it. ‘Nitro-Chalk’ (21% N) was used as the standard for comparison. The liquid N-fertilizer was made from urea and ammonium nitrate; the herbicide was a mixture of dichlorprop and MCPA. Each experiment tested all combinations of the two N fertilizers applied to give 38, 75 or 113 kg N/ha without the herbicide and with either 2·8, 5·6 (recommended dose) or 8·4 1/ha of herbicide. The 24 treatments were applied to winter wheat at growth stages 4–5 of the Feekes scale, to barley at growth stage 5 and to grass in late spring and again to regrowth after cutting.

Herbicide alone sometimes scorched the leaves but seldom badly. Liquid N-fertilizer nearly always scorched the leaves and the amount of scorch was increased by adding herbicide; scorch also was increased by increasing the amount of either and so was most severe when most liquid fertilizer and most herbicide were sprayed together; this damage did not decrease yields appreciably except when only 38 kg N/ha was given.

Spraying the herbicide with the liquid fertilizer always gave slightly better weed control than herbicide alone in the wheat, but not always in the barley; in the grass, weed control was no better than from herbicide alone.

‘Nitro-Chalk’ gave larger yields of wheat grain than the liquid N-fertilizer did in seven of nine comparisons without herbicide and in 20 of 27 with it, of barley grain in five of nine comparisons without herbicide and in 15 of 27 with it, of permanent grass in 25 of 27 comparisons without herbicide and in 70 of 81 with it, and of perennial ryegrass in nine of nine comparisons without herbicide and in 25 of 27 with it. Thus herbicide did not alter the advantage that ‘Nitro-Chalk’ had.

Percentages of N in the crops were larger with ‘Nitro-Chalk’ than with the liquid N-fertilizer but were changed little by herbicide.
The effect of two feeding levels of diets containing field-cured or frozen Rhodes grass (Chloris gayana), on digestibility and rumen metabolites in sheep
Authors: Tagari H. , Ghedalia D. Ben , Shtern Y.
Published: March 2009

A digestibility and metabolism experiment was carried out to study the effect of two levels of feeding Rhodes grass-concentrate mixed diets when the grass had been preserved as hay or as frozen grass. Twenty Awassi lambs were used.

The method of preserving the Rhodes grass did not affect the digestibility of dry matter, crude protein or nitrogen-free extract. However, the digestibility of energy and crude fibre was lower with the hay treatments.

A consistent trend towards higher digestibility of the diets' constituents was observed with the high level of feeding.

Acetic acid concentration in the rumen was lower with the hay than with frozen grass. Feeding the high level resulted in higher concentrations of volatile fatty acids in the rumen.

A highly significant effect of the level of feeding on the C2/C3 ratio was observed; the high level of feeding resulted in a lower C2/C3 ratio
The genetic control of red cell glutathione deficiencies in Finnish Landrace and Tasmanian Merino sheep and in crosses between these breeds
Authors: Tucker Elizabeth M. , Kilgour L. , Young J. D.
Published: March 2009

Finnish Landrace sheep with low red cell GSH concentrations resulting from a defective transport system for certain arnino acids were crossed with Tasmanian Merino sheep with a red cell GSH deficiency due to impaired activity of the enzyme γ-glutamyl cysteine synthetase. Inheritance data showed that the two types of GSH deficiency were under independent genetic control. In the Finnish Landrace breed, the gene coding for the transport defect (Trn) was inherited as an autosomal recessive and sheep homozygous for this gene had high red cell concentrations of lysine and ornithine (Ly ×) as well as low levels of GSH. In the Tasmanian Merino breed the GSH deficiency behaved as if controlled by an autosomal dominant gene (GSHL). Backcross breeding experiments resulted in lambs which had inherited both types of GSH deficiency. Evidence suggested that such ‘double low’ GSH lambs had an impaired viability. In Tasmanian Merinos the GSH deficiency was established prior to birth. Newborn Finnish Landrace lambs were clearly separable into two types on the basis of their red cell lysine and ornithine content but not on their GSH concentrations.
Game domestication for animal production in Kenya: theory and practice
Authors: King J. M. , Heath B. R. , Hill R. E.
Published: March 2009

The term game is applied to those wild animals which are pursued in the chase or kept for pleasure. When an animal has been domesticated it belongs to the family, lives in or near the habitations of man and is tame, not wild.

Wild African buffalo, eland, oryx and gazelle were caught by either dart-immobilization, chasing and roping, or driving into a corral. Weaned, sub-adult animals were preferred. The taming procedures started in small, dark, padded cells and progressed through a series of larger enclosures until the animals were grazing in a 40 ha paddock 7 weeks after capture. Gazelle was the only species which was not established as a domestic herd by this method, because of its liability to self-inflicted injuries.

The domestic game animals were grazed over thousands of hectares without fencing, but under supervision of herdsmen. They were subjected to standard domestic animal husbandry procedures including eartagging, dehorning and castration.

The conclusion is that some African game animals are easy to domesticate as has also been demonstrated in the prehistoric and recent past. The reason they have not displaced conventional livestock can be found in the history of domestication. The condition originated in the Middle East and spread mainly by the introduction of an alien culture and livestock to Africa. The time when sub-Saharan Africans had established a suitable way of life for domestication coincided with the arrival of cattle, sheep and goats forced south by the desiccating environment.

The potential of African game animals to domestic animal production will be evaluated in subsequent papers.
Effects of previous cropping and N fertilizer on grain yield and take-all in spring barley
Authors: Slope D. B. , Etheridge Judith
Published: March 2009

Grain yield and incidence of take-all were measured in barley grown continuously and in successive barleys after two crops (oats, beans) not susceptible to the take-all fungus. Without fertilizer N, first barley crops after beans yielded about 1 t/ha more than second barleys and 2 t/ha more than third; growing more barleys did not further lessen yield. With increasing amounts of fertilizer N yields of barleys after barley nearly equalled yields of barley after beans. Take-all increased to a maximum in third barleys and was decreased by N, but it was not possible to separate the effects of take-all andsoil and fertilizer N on yield.
A comparison of spring barley grown in England and in Scotland. 2. Yield and its components
Authors: Ellis R. P. , Kirby E. J. M.
Published: March 2009

Yields of two spring barley varieties, Golden Promise and Maris Mink, were greater at the Scottish Plant Breeding Station (SPBS) than at the Plant Breeding Institute (PBI) in both 1976 and 1977. In both seasons more ears per plant were produced and the number of grains per ear was greater at the SPBS. Weight per grain was greater at the Scottish Plant Breeding Station in both 1976 and 1977, but the distribution of grain size along the ears differed between seasons. Grain at the tip of the ears of plants grown at SPBS in 1976 was lighter than the corresponding grain on the Cambridge-grown plants. In 1977 the SPBS-grown plants had heavier grains at all the main shoot spikelet positions. At the SPBS the relative difference between main shoot and tillers 1 and 2 was smaller than at the PBI.

These results are taken to indicate that the combination of climatic factors in Scotland affects plant development in such a way that intraplant competition is reduced and more spikelet primordia survive to form grains and more tillers produce fertile ears.
Milk secretion studies with New Zealand Romney ewes: Parts V–XI
Authors: Barnicoat C. R. , Murray P. F. , Roberts E. M. , Wilson G. S.
Published: March 2009

Experiments on the milking qualities of New Zealand Romney ewes, maintained at liberal standards of grazing and at different planes of nutrition under stall-feeding conditions, were described in four earlier papers published in this Journal (Barnicoat, Logan & Grant, 1949).

In the meantime several other original papers in this field have appeared: Coop (1950) studied the effect of certain factors including milk intake on the growth and development of lambs of various breeds of sheep in the South Island of New Zealand; Barnicoat (1952) discussed some practical applications of the work; Owen (1953), employing a modified technique for measuring milk yields of Welsh hill ewes, found that the correlations between lamb gains and estimated milk yields were of a similar order to those established elsewhere under easier conditions of farming; Thomson & Thomson (1953) carried out experiments with Cheviot ewes fed indoors, and their results support the viewpoint that adequate nutrition in the final stages of pregnancy is of paramount importance; and Gill & Thomson (1953) discussed the significance of milk yield of ewes under farming conditions in Great Britain which contrast widely with conditions pertaining to the district in which the experiments described in this series of papers were conducted.
Plant-breeding studies in leguminous forage crops III. Preliminary studies on the developmental physiology of English stocks of beans (Vicia faba L.)
Authors: Chakravarty A. K. , Drayner Jean M. , Fyfe J. L.
Published: March 2009

1. The reaction of spring and winter types of field beans and of Windsor broad beans to artificial vernalization treatments and to successional field sowing has been studied.

2. The broad bean type came into flower earlier and at a lower node on the stem than any of the field bean types, and this was not affected by either vernalization treatments or successional sowing.

3. The field bean types flowered at a low node when sown in winter, but in summer sowings the level of the first flowering node was much higher; the response of the winter types was more extreme than that of the spring types.

4. In the summer sowings vernalized plants came into flower earlier and at a lower node than unvernalized, but in the winter sowings both vernalized and unvernalized material flowered at an equally low node.

5. A convention for naming the different stems contributing to the yield was evolved, and using this it was shown that the date of sowing affected the stems produced.

6. The survival of plants in the field was not found to be affected by vernalization previous to sowing.
The metabolic changes which occur in sheep transferred to lush spring grass I. Changes in blood and rumen constituents
Authors: Annison E. F. , Lewis D. , Lindsay D. B.
Published: March 2009

1. Changes are observed in the concentrations of a wide range of substances found in blood and rumen contents when sheep are first turned out to lush spring grass.

2. With some metabolites (e.g. rumen α-amino nitrogen, blood VFA) the increase is only temporary, and the animal (or its rumen microbial population) quickly adapts to the changed conditions. With other metabolites (e.g. rumen VFA) there is a sustained increase over a period of at least three weeks on grass.

3. It is possible that the nature of the previous diet may determine the magnitude of the metabolic changes occurring.

4. The overall nature of these changes should be taken into account in assessing the aetiology of the metabolic diseases occurring in ruminants under similar conditions.
A multivariate study of pig carcass growth and composition: 2. Dissected tissues and parts
Authors: Evans D. G. , Kempster A. J.
Published: March 2009

An analysis of pig carcass composition was carried out, using data for 11 genetic source populations in the Meat and Livestock Commission's Commercial Pig Evaluation (CPE). The data were from years 3–5 of CPE and a total of 720 carcasses were involved. Weights of dissected tissues and parts were considered simultaneously, and the effects of growth, source population, sex, feeding regimen and time period were incorporated into an integrated model, the multivariate allometric development model.

Canonical variates were constructed for each of the classifying factors except time period, and the residual variation in carcass composition was analysed by principal component analysis. The first canonical variate for source populations was interpreted as a tissue distribution characteristic associated with the distribution of lean between joints in the dorso-cranial and ventro-caudal regions of the carcass. It accounted for 39% of the variation between source populations. The second canonical variate was associated with the ratio of subcutaneous fat to lean in the carcass, and accounted for 20% of the variation between source populations. The results explain the bias found in predicting the proportion of lean tissue in a carcass from subcutaneous fat thickness (P2).

In a graphical display of differences between source populations, nine were shown to be distinct, with only two intermediate and not clearly differentiated from some others. The interpretation of canonical variates and the relative positions of the populations were closely related to those obtained from the analysis of production and grading characteristics in the first paper of the series.
Some results of an experiment to compare ley and arable rotations at Woburn
Authors: Mann H. H. , Boyd D. A.
Published: March 2009

The effect of short leys and arable cropping on the yields of the following arable crops has been tested since 1937 at Woburn Experimental Farm, Bedfordshire. The leys were a 3-year grazed ley and 3 years of lucerne cut for hay and the arable cropping was potatoes, winter cereal and either a 1-year ley or a third tillage crop. The effects of these crop sequences were measured by test crops of potatoes and barley, uniformly treated except that 15 tons farmyard manure was applied on one-half of each plot for potatoes.

Without farmyard manure, the yield of potatoes after the grazed ley was higher than after three tillage crops by an average of about 3 tons per acre; after lucerne it was about 2 tons per acre more than after the tillage crops and after the 1 -year ley under 1 ton per acre more. With farmyard manure the benefit from leys was less (about 2 tons per acre for both lucerne and the grazed ley). The average effect of the farmyard manure was about 2·8 tons except after the grazed ley, where the increase was only 1·6 tons per acre.

Effects of the previous cropping on the yield of barley were small in the early years of the experiment, but in the last 5 years the yield after ley and lucerne has exceeded that after the tillage crops by about 15%.

Part of the difference in potato yield between the ley and arable sequences can be attributed to the differential incidence of potato-root eelworm, which has reached a high level of infestation on some of the arable plots. Much of the remainder may be ascribed to the low level of basal manuring which has affected the yield of all plots, but particularly those under tillage crops. How far the observed differences can be explained by these considerations remains a matter for speculation, but may to some extent be clarified when further results are obtained from a revised scheme of cropping and manuring.
A study of the effects of dietary aureomycin and methods of weaning in early weaned calves
Authors: Quayle Peter D.
Published: March 2009

Though there has been a considerable amount of recent research on the early weaning of calves, few scientific papers have been published. Preliminary studies at the Rowett Institute have indicated that early weaned calves show greater thriftiness and increased liveweight gains when small quantities of antibiotics are included in the diet (Preston, 1955). Pilot trials carried out at Cockle Park in 1955/6 suggested that there is little difference between the performance of abruptly and gradually weaned calves (Quayle, 1956a). This present study has been carried out to verify these observations, and includes some comments on nutritional scouring.
Variation in lean distribution among steer carcasses of different breeds and crosses
Authors: Kempster A. J. , Cuthbertson A. , Smith R. J.
Published: March 2009

Dissection data for 753 steer carcasses comprising 17 breed-type × feeding system groups were used to examine the distribution of lean between 14 standardized commercial joints. Breed types included Ayrshire, Friesian, Friesian × Ayrshire and crosses out of Friesians by Angus, Charolais, Hereford, Limousin, Simmental and South Devon sires. Most cattle were grown on cereal or grass/cereal systems of feeding. Group means for weight of lean in the side (half carcass) ranged from 60·0 to 85·2 kg with a pooled within-group S.D. of 7·81 kg.

The increase in lean weight in each joint relative to that in the side was examined using the allometric equation. Pooled within-group growth coefficients (b values) indicated that relative lean tissue growth was lowest in the leg (hind shin) and rump (b = 0·84 ± 0·03 and 0·85 ± 0·03 respectively) and highest in the clod and sticking (b = 1·19 ±0·03). The result for the combined higher-priced joints was 0·95 ±0·01.

The pooled growth coefficients were used to adjust the weight of lean in each joint to equal total lean weight in the side where this was legitimate. Statistically significant (P < 0·001) but relatively small differences were recorded between groups in the adjusted means for all joints tested. At equal total lean weight, Charolais × Friesian, Limousin × Friesian and Simmental ×; Friesian groups had the highest weight of lean in the combined higher-priced joints and the Ayrshire and Friesian × Ayrshire groups the lowest. The difference between the two extreme groups was 2·1 kg (for one side).
Chemical treatments for increasing the digestibility of cotton straw: 1. Effect of ozone and sodium hydroxide treatments on rumen metabolism and on the digestibility of cell walls and organic matter
Authors: Ben-Ghedalia D. , Shefet G. , Dror Y.
Published: March 2009

The digestibility and rumen metabolism of diets containing as 50% of their organic matter (OM), cotton straw (CS) untreated, treated with sodium hydroxide and treated with ozone, were studied in sheep cannulated in the rumen and at the duodenum with simple cannulae. The concentration of total volatile fatty acids (VFA) in the rumen of sheep given the ozone and NaOH treatments was higher than in the untreated diet; however, the VFA profiles were not different. The rumen dehydrogenase activity, suggested to reflect general microbial activity, was higher by 83 and 81% in the ozone and NaOH treatments respectively, than in the untreated.

Apparent digestibility of organic matter in the ozone-treated diet was 74·6%; 1·25 and 1·17 times higher than in the untreated and NaOH-treated diets respectively. The calculated values for organic matter and cell-wall digestibilities of the cotton straw in the complete diets were: 30·0, 20·0; 60·8, 60·0; and 39·6, 39·7%, respectively, for the untreated, ozone and NaOH-treated cotton straw. Nitrogen metabolism was not impaired by the presence of formic acid in the ozonated cotton straw; the apparent absorption of N from the intestine and the apparent digestibility of N were higher in the ozonetreated diet than in the untreated or NaOH-treated diet.

The proportion of organic matter and cell walls digested in the rumen was higher in the NaOH and ozone treatments than in the untreated, and the possible reasons for that are discussed. A positive relationship was found between cell-wall digestion in the rumen (% of intake) and the rate of passage (% per h) of particulate matter from the rumen. The interpretation of this relationship is discussed in general and in view of the results of the present study.
Digestibility of rumen bacterial cell proteins in buffaloes and goats
Authors: Verma D. N. , Singh U. B.
Published: March 2009

The digestibility of protein of mixed whole rumen bacterial cells and Streptococcus bovis were determined in Bos bubalis and goats. The bacterial cells were labelled either with 35S or 14C in vitro incubation and were injected in a single dose into the rumen after protecting by formaldehyde treatment. Faeces were collected for 6 consecutive days and radioactivity excreted in the faeces was measured. The digestibility of bacterial protein ranged from 81·7 to 96·8% in both the species.
The relationship between nitrogen supply and the nitrogen yield of cut grass swards
Authors: Richards I. R. , Hobson R. D.
Published: March 2009

Using data from 140 experiments conducted at sites throughout England and Wales, a relationship between nitrogen supply and the nitrogen yield of cut grass swards was sought. One linear and three non-linear functions were fitted to the data. The non-linear functions fitted the data slightly better than did the linear and, over the range in nitrogen supply normally found, provided consistent predictions of grass nitrogen yield. The recovery of available nitrogen in the herbage was found to decline with level of nitrogen supply from a potential maximum of 79%.
Some physical properties that affect the rate of diffusion of oxygen into silage
Authors: Rees D. V. H. , Audsley E. , Neale M. A.
Published: March 2009

Experiments are described which study the effect of density and chop length on the rate of diffusion of oxygen into silage and equations are presented which enable the rate of diffusion to be calculated under laboratory conditions. The concept of zero porosity is also discussed and methods of calculating the density at which it occurs are given. The effect of carbon dioxide on the rate of diffusion is also discussed.
Effects of early application of chlormequat on tillering and yield of winter wheat
Authors: Kettlewell P. S. , Whitley Eleri A. , Meredith W. S. , Sylvester-Bradley R.
Published: March 2009

Early investigations into the effects of the growth retardant chlormequat on wheat and barley showed that in the absence of lodging the number of ears was frequently increased following treatment at the beginning of stem elongation (Humphries, Welbank & Witts, 1965; Alcock, Morgan & Jessop, 1967; Barrett, Meens & Mees, 1967). More recently, earlier applications, at the three-leaf stage, to barley have been shown to be more effective in increasing the number of ears (Koranteng & Matthews, 1982). However, there appears to be little information on the effects on number of ears of early application of chlormequat to winter wheat. Therefore, in 1982 three field experiments were carried out to investigate the effects of early application of chlormequat on the numbers of tillers and ears and grain yield of winter wheat.
An analysis of cattle live-weight changes on tropical grass pasture during the dry and early wet seasons in northern Australia: 2. Relations to trends in the pasture, diet and grazing behaviour
Authors: McCown R. L. , McLean R. W.
Published: March 2009

Cattle grazing buffel grass pastures during the dry season at Katherine lose large amounts of live weight during a short period following first rain. In Part 1 we showed that these losses were due mainly to reduction in gut contents. Part 2 examines the changes in pasture, diet and grazing behaviour to assess the probable change in nutritional status of cattle following rain.

During the dry season the most valuable pasture component, green leaf, was very scarce and had a nitrogen concentration of about 1%. Diets of oesophageally-fistulated cattle contained less than 0·5% N. Shortly after first rain diet N doubled owing both to rapidly increasing amounts of green leaf and to the increase in N concentration in young leaf to over 3%. Although intake was not measured, literature is cited to show that this increase in dietary N would be expected to increase rumen digestion rates with a resultant marked increase in D.M. intake and a reduction in gut contents.

Although availability of high quality herbage increased very rapidly following first rain, a period of increased nutritional stress immediately following rain could not be ruled out. However, any such decline in nutrition appears to be short-lived.
Comparison of spring barley varieties grown in England and Wales between 1880 and 1980
Authors: Riggst T. J. , Hanson P. R. , Start N. D. , Miles D. M. , Morgan C. L. , Ford Margaret A.
Published: March 2009

Five experiments, involving 37 varieties, were carried out over three seasons to estimate the increase in yield potential in spring barley achieved by plant breeding during the last 100 years. Most of the important spring barley varieties grown in Britain between 1880 and 1980 were represented. In three experiments disease was controlled by a fungicide while in the other two experiments fungicide application was a main treatment. To prevent yield loss due to lodging, plants were supported as a main treatment in two trials.

In all experiments most of the modern varieties yielded more than the older ones. The genetic gain in yield was 0·39% per year during the 100-year period and 0·84% per year between 1953 and 1980.

Modern varieties had higher grain yields, shorter straw, and higher harvest index denned as the proportion of grain dry weight to total above-ground dry weight; more of the tillers they produced survived to give ears. There was a weak association between biological yield (total above-ground dry weight) and grain yield.

It is suggested that although much of the improvement in yield described here could be attributed to increased harvest index, the scope for further improvement in this character may be limited. Further yield improvements might be achieved by combining high biological yield with high harvest index.
The effect of weight at mating and of nutrition during mid-pregnancy on the birth weight of lambs from primiparous ewes
Authors: Russel A. J. F. , Foot Janet Z. , White I. R. , Davies G. J.
Published: March 2009

Forty-eight approximately 18-month-old Scottish Blackface ewes were used to study the effects of two levels of nutrition during mid-pregnancy (30–98 days of gestation) on the birth weight of lambs from ewes varying in weight, size and condition at first mating. The mean live weight (42–4 kg), size index (31–9) and condition score (2–4) at mating of the 26 ewes from flock A were all less than those of the 22 ewes from flock B (54–5, 39–4 and 2–9 respectively). Mean intakes of the low and high nutritional treatment ewes during mid-pregnancy were 10–6 and 22–0 g/kg/day respectively of a pelleted diet supplying 8–81 MJ metabolizable energy and 125–5 g crude protein/kg. These intakes produced estimated changes in net maternal weight of approximately – 5 and 0 kg respectively.

Mean lamb birth weights from ewes on the low and high nutritional treatments were:flock A, 3–32 and 3–83 kg; flock B, 4–96 and 4–23 kg respectively. Analyses showed intake during mid-pregnancy to have a positive effect on lamb birth weight in the flock A ewes, and a negative effect in flock B ewes. Mating weight accounted for 78% of the variance in birth weight in the low nutritional treatment ewes but had little effect in those on the higher level of feeding.

The practical implications of the results are discussed in relation to levels of juvenile nutrition.
The effects of genotype, sex and feeding regimen on pig carcass development: 2. Tissue weight distribution and fat partition between depots
Authors: Kempster A. J. , Evans D. G.
Published: March 2009

Dissection data for 1006 carcasses taken from the first 2 years of the Meat and Livestock Commission's (MLC) Commercial Pig Evaluation (CPE) were used to examine the growth of tissue weights in joints relative to the corresponding total tissue weight in carcass, and the growth of fat depots relative to total fat over the carcass weight range, 46–92 kg. Growth relationships were examined using a linear allometric model. Differences in tissue weight distribution between genotypes (pigs from different companies in CPE), sexes (barrows and gilts) and feeding regimens (restricted and ad libitum feeding) were examined at constant lean, bone or fat weight as appropriate, common allometric regression slopes being assumed.

Lean and bone showed the same pattern of development. Relative growth was lowest in the proximal limb joints (ham and hand) increasing inwards to the joints of the back. With minor differences, the same pattern was found for subcutaneous fat and intermuscular fat. Fat depots differed considerably in their growth relative to total fat: intermuscular fat grew more slowly (allometric growth coefficient, b = 0·87), subcutaneous fat at the same rate and perinephric and retroperitoneal fat (flare fat) more rapidly (b = 1·24).

Significant differences were recorded between genotypes in lean distribution and in the distribution of fat depots. However, the differences were small and of little commercial importance. There were also differences in fat partition between genotypes, flare fat being the most variable depot.

Sex and feeding regimen also influenced tissue distribution and fat partition.

The results are discussed in relation to the robustness of regression equations for predicting overall carcass composition from subcutaneous fat measurements and sample joint dissections.
Field measurements of water use for irrigation control in Kenya coffee
Authors: Pereira H. C.
Published: March 2009

The paper presents the results of 10 years of soil moisture studies in arabica coffee in high altitude tropical conditions. Very deep soils and contrasting wet and dry seasons give unusually favourable conditions for soil moisture measurements.

Volumetric measurements on soil cores are reported for 10 ft. depth of soil, which is shown to include most of the root system of arabica coffee, and holds 48 in. of water under field conditions when active drainage has ceased. This is shown to correspond to a soil moisture tension of 1/3 atm. Of the 48 in. of water only 12 are available to plants. Wilting points determined by sunflower seedlings on soil samples to 15 ft. depth are shown to agree well with field sampling under wilting conditions in coffee plantations.

A series of seasonal factors relating the water use of the coffee crop to the readings of an evaporation pan are presented, and their application over 6 years is shown to check with soil sampling data within the limits of sampling error. This method is proposed for control of supplementary irrigation under conditions of limited water supply, but a distillation-type radiation integrator can with advantage replace the evaporation pan.

The balance of the hydrological equation for this crop is demonstrated in each of the 6 years.
Gamma radiation in the preparation of maize silage for studies on the aerobic deterioration process
Authors: Woolford M. K.
Published: March 2009

Maize silage was exposed to doses of y radiation varying from 0 to 6 Mrad inclusive and the effects of this treatment on the microflora and possible changes it might impose on the chemical composition were monitored. The highest dose was required to reduce the native population of micro-organisms to an insignificant level and only minor losses of lactic acid and ethanol were sustained. In addition, the irradiated silage was inoculated with representatives of groups of micro-organisms implicated in the aerobic deterioration of silage and the subsequent changes upon exposure to air observed. The inoculum proliferated and induced losses of fermentation acids, water-soluble carbohydrates, dry matter and, to a minor degree, neutral detergent fibre, and resulted in an increase in temperature and total nitrogen, the factors most likely to change during aerobic deterioration. Only the 6 Mrad dose yielded material suitable for investigations into the identification of those organisms primarily responsible for aerobic deterioration.
The potential of maize as a forage crop in Scotland
Authors: Potts M. J. , Waterson H. A. , Rodger J. B. A. , McMartin I.
Published: March 2009

Between 1972 and 1976 a series of 15 trials was carried out at various climatically favoured sites throughout Scotland to assess the potential of new hybrid maize varieties of European origin under Scottish conditions. No meaningful differences were found between varieties in respect of dry-matter yield or maturity.

Seed rates ranged from 100 to 200 × 103 seeds/ha giving final stands from 40 to 194 × 103 plants/ha. Regression analyses for the variety Dekalb 202 included in 54 treatments indicated that the relationship between plant population density and dry-matter yield was partly linear with an important quadratic function, suggesting an optimum of 179 × 103 (± 80 × 103) plants/ha. Plant population density accounted for 65·9% (P < 0·01) of the variance in dry-matter yield but was not significantly related to dry-matter content.

Climatic variation between years had no overriding influence on growth and development. Dry-matter production for the variety Dekalb 202 sown in mid-May ranged from 2·86 (1972) to 14·54 t/ha (1975) with associated dry-matter contents of 15·1 and 24·1% respectively. In a few instances slightly higher dry-matter contents (maximum 28·6%) from mid-May sowings were associated with lower yields.

Neither date of sowing nor accumulated temperature to harvest measured as Ontario Heat Units was significantly related to yield but date of sowing accounted for 29·5% (P < 0·01) of the variance in dry-matter content. Accumulated Ontario Units at harvest were not significantly related to dry-matter content.

An interesting relationship between dry-matter yield and the date on which the crop had received 1379 Ontario Units was found. This relationship may be useful in selecting sites at which maize may be grown or to predict maximum potential final yield in any given season.
Response to the use of Merino in improvement of coarse-wool Barki sheep: an analysis of some cross-bred wool traits
Authors: Guirgis R. A.
Published: March 2009

A study was carried out during three successive years from 1970 to 1972 on different wool types. Breed groups involved were Merino (M), coarse-wool Barki sheep and five of their crosses. Traits studied were greasy-fleece weight, clean-fleece weight, kemp score and means of staple length and fibre diameter in the whole fleece.

The heaviest greasy fleeces were produced by ¾ followed by ⅝ M. Total average greasy fleece weight of the crosses was 3·43 kg. There was a general trend of increase in greasy fleece weight with increasing Merino proportion.

The total average percentage clean yield of the crosses was 42·2, and ½ M and ¾ M produced the heaviest clean fleeces. The total average clean fleece weight of the crosses was 1·44 kg. Skirting the fleeces caused a reduction in the within-fleece variability of staple length and diameter. Percentages reduction for staple length were 10·3, 9·6 and 14·6 and those for fibre diameter were 2·4, 5·0 and 9·5 in Barki, crosses and Merino respectively.

Barki had the coarsest diameter and the whole fleece of ¾ M showed the finest mean diameter of the crosses. The within-staple variability in distribution of fibre diameter was high in Barki and throughout the crosses. The average percentage medullated fibres was highest in Barki and decreased throughout the series of crosses. The ¼ M had the highest frequency medullated fibres of the crosses.

The longest mean staple in the crosses was produced by ¼ M. The within-fleece variability in staple length was generally low. In the crosses, the variability assumed slightly higher values than those of the parental breeds.

Kemp production was mainly contributed from the dorsal line, particularly from the back and hip.

As regards some wool and mutton characteristics, ⅝ M might be considered the most suitable cross-bred type.

With increasing Merino contribution in the crosses, the mean fibre diameter showed a decreasing trend, but a high within-staple variability was maintained throughout the crosses. Inter se mating, in most of the crosses, produced animals that showed relatively more uniformity between fleeces than either both or one of the crosses. Inter se mating of the different cross-bred types with selection of the desired uniformity in length and diameter would be recommended.