bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of overseas pig breeds using imported semen. 2. Prediction of carcass lean content
Authors: Sutherland R. A.
Published: March 2009

An analysis of data from the complete dissection of one side from 285 animals from a breed comparison experiment was conducted to determine whether there were important biases in the prediction of percentage lean in the side based on dissection of the rumpback joint and, if so, whether the dissection of any of five other sample joints would have been better.

For estimating lean content of the side, it was found that the lean content of any sample joint except the hand was a more precise predictor than standard carcass measurements alone, while including the latter in a prediction equation based on a single sample joint dissection improved precision further. For prediction based on lean in the sample joint alone, any one of the ribback, ham and rumpback was best. If other carcass measurements were included (in particular, C fat depth, eye-muscle area and trimming percentage were found to be useful), there was little to choose between the joints. For all joints there were differences between sire breeds (Large White, Canadian Yorkshire, U.S. Duroc, U.S. Yorkshire, Danish Landrace or Norwegian Landrace), sexes (hog or gilt) and feeding regimens (ad libitum or scale) in lean content of the side at constant lean content of the sample joint, but the regression slopes differed only when the rumpback or streak was used as a predictor, and then only between ad libitum and scale-fed pigs. It will therefore be important in any future such experiment fully to dissect a sample of each class (breed, feeding regimen and sex) to provide unbiased estimates of the differences in lean content. A sample of 30 from each class should allow the differences to be estimated adequately.
The ratio of naturally occurring 13C and 12C isotopes in sheep diet and faeces as a measurement for direct determination of lucerne hay and maize grain digestibilities in mixed diets
Authors: Bruckental I. , Halevi A. , Amir S. , Neumark H. , Kennit Hanna , Schroeder G.
Published: March 2009

Two experiments were conducted with eight rams in a latin-square design of four treatments with different lucerne hay (LH): maize grain (MG) ratios: 100:0, 80:20, 50:50 and 20:80. In Expt 1 the amount of food offered was restricted to 1 kg/day. In Expt 2 the rams were offered 1·5 kg/day, which was about the maximum amount the animals in the 100% LH treatment were able to consume. Animals were kept on each treatment for 4 weeks; during the final 8 days the faeces were oollected and weighed for each animal and analysed for dry matter, organic matter (OM), crude fibre and δC

The values of δC in LH, MG and different faeces samples were used for direct determination of LH and MG digestibilities of mixed diets in the different treatments.

The increase of MG in the ration and the decrease of LH improved the digestibility of total OM. The effect of MG was more pronounced at the low than at the high level of consumption. At the low level of intake, an increase in the amount of MG in the ration did not affect the digestibility of LH, and MG digestibility was close to the extrapolated value. At a food intake level 1·5 times that of Expt 1, the addition of grain to more than 50 % of the ration caused a marked depression in digestibility of LH.

Results of the δC method were discussed in comparison with calculated values of LH and MG digestibilities and with whole ration crude-fibre digestibility.
The melting point, iodine value, fatty acid composition and softness index of carcass fat in three different breeds of suckled lambs in Greece
Authors: Zygoyiannis D. , Stamataris C. , Catsaounis N.
Published: March 2009

Suckled single lambs, 6 weeks of age at slaughter, were used to study the melting point, iodine value, fatty acid composition and softness index of carcass fat. The lambs, born in mid-October in central Greece, were suckled from birth to slaughter and received no supplementary feed. They consisted of 43 Sarakatsaniko, 22 Karagouniko and 29 Chios x (East Friesland x Karagouniko). At slaughter, samples of subcutaneous fat from the base of the tail and perinephric fat were removed and stored at – 10 °C until analysed.

Melting point and iodine value were determined by the Association of Official Analytical Chemists (1980) and International Union of Pure and Applied Chemistry (1977) methods of analysis. Gas-liquid chromatography, on 12% diethyleneglycol succinate as stationary phase, was used for fatty acid methyl esters analysis. Softness index was calculated.

Component fatty acids in decreasing order of proportion in total fat were oleic, palmitic, stearic, myristic, palmitoleic, linoleic, linolenic, lauric and capric acids. The total of odd-numbered n-acids and branched chain acids occupied a position approximately mid-way. There was very little evidence of differences between the sexes. However, the differences between the two fat depots and those between breeds were significant in most of the traits. Significant correlations between some of the traits studied and also linear regression equations between selected variables were obtained.
Circadian rhythm in wool depilation force in Merino and Merino X Border Leicester sheep
Authors: Foldes A. , Donnelly J. B. , Maxwell C. A. , James S. B. , Clancy S. L.
Published: March 2009

As part of an ongoing investigation of ovine neuroendocrine mechanisms relating to photoperiod and eventually to wool growth, the diurnal variation of depilation force (an index of the strength of attachment of wool fibres to the skin of sheep) was investigated in Merino wethers and Border Leicester Merino ewes. Circadian rhythms were demonstrated in depilation force in both ewes and wethers. Further experiments were performed to investigate circadian endocrine rhythms which may have some bearing on the observed rhythm in depilation force. Circadian rhythms 180° out of phase with the depilation force rhythm were observed in plasma cortisol concentrations and in pineal serotonin N-acetyltransferase activities in Merino wethers.
Further comparisons of energy and protein sources for growing cattle
Authors: Smith T. , Siviter J. W. , Merry R. J.
Published: March 2009

Spring-barley straw or maize silage were the major components in mixed diets of compound and forage fed to yearling dairy heifers. With straw, rolled barley was fed either alone or with fishmeal, soya-bean meal, protected soya-bean meal, whey + urea or Ewoplua (a product made from whey and rich in lactosyl urea). With maize silage the rolled barley was fed either alone or with fishmeal, whey + urea or Ewoplus.

When straw was included in the diet fishmeal and protected soya-bean meal increased live-weight gain, and all the supplements increased nitrogen retention. When maize silage was fed, only fishmeal increased live-weight gain although all the supplements increased digestibility. Concentrations of rumen NH3-N were increased by all the supplements, when fed with straw, and also by maize silage when fed without an N supplement or with fishmeal. Small changes were noted in total and molar proportions of VFA.

Calculated ME intakes suggested a more efficient use of energy for growth from maize silage than from straw, except when the straw diet was supplemented with fishmeal.
Mutagenic activity of alachlor, butachlor and carbaryl to a N2-fixing cyanobacteriumNostoc muscorum
Authors: Vaishampayan A.
Published: March 2009

Alachlor, butachlor and carbaryl were highly toxic to the N2-fixing cyanobacteriumNostoc muscorum, when grown on solid minimal (nitrogen-free) medium. At pesticides doses allowing about 20, 50 and 60% survival of the organism, various mutations were obtained inN. muscorum, reverse mutation fromhet+nif–andhet–nif+auxotrophy tohet+nif+prototrophy, forward mutation for resistance to 0·37 mM L-methionine-DL-sulfoximine, and auxotrophic mutation for the achievement of carbon-auxotrophy through 5 mM methylamine-resistance. The toxic and mutagenic effects of the three pesticides were similar to those of the well known mutagen MNNG.
Comparative behaviour of seedlings of sorghum and some tropical legumes in relation to leaf expansion and growth
Authors: Chopra R. K. , Koundal K. R. , Kansal Madhu
Published: March 2009

Growth rates were compared of pigeonpea (Cajanus cajan), moth bean (Vigna aconitifolia), mung bean (Vigna radiata) and sorghum seedlings aged 2–5 weeks. The seedling growth rates were analysed in relation to leaf area development, net photosynthetic rate, nitrogen accumulation, nitrate reductase activity, and soluble protein content. Growth rates were highest in sorghum and lowest inC. cajan. Leaf area development was very fast in sorghum and very slow inC. cajan. Net photosynthetic rate of sorghum leaves was double that observed for the legume leaves. No significant difference was observed in nitrate reductase activity, nitrogen percentage or soluble protein content between sorghum and the legumes. In sorghum, early investment of assimilates into leaf development ensured a higher assimilation of carbon and nitrogen per plant. In the legumes, slow development of leaf area coupled with low photosynthetic rates probably resulted in slow growth of the seedlings. In the legume seedlings, vigour was related to the rates of leaf area expansion. Leaf area expansion rates were not related to the nitrogen status of the leaf in the species examined.
Investigations in the Triticinae II. The cytology and fertility of intergeneric and interspecific F1 hybrids and their derived amphidiploids
Authors: Bell G. D. H. , Sachs Leo
Published: March 2009

1. Chromosome pairing has been studied in twenty-two different sterile F1 hybrids involving the genera Aegilops, Agropyron and Triticum, together with their colchicine derived amphidiploids having chromosome numbers of 2n = 42, 56 and 70. Cytological evidence has been correlated with male and female fertility, while chromosome pairing in the parents has been studied in relation to their amphidiploids.

2. Some of the sterile F1 hybrids showed little or no pairing, while in others the pairing was appreciable. There was an association of the amount of pairing with the parental combinations used in the production of the hybrids in that the interspecific hybrids were characterized by a relatively high degree of pairing, particularly those with 28 chromosomes, while the intergeneric hybrids either lacked pairing or showed a low incidence.

3. In the A1 amphidiploid generation, chromosome pairing was in all cases high, and in some cases almost complete. In all cases multivalent formation in the amphidiploid was lower than bivalent formation in its undoubted F1 hybrid. Different amphidiploids showed various degrees of differential affinity. Univalent formation occurred in some amphidiploids, while bivalent formation in some was increased by a loss of chromosomes.

4. In all cases there was a reduction in chiasmata per nucleus and chiasmata per bivalent in the amphidiploid compared with its parent species. Reduction values were not directly associated with any increase in chromosome number of the amphidiploid, nor with the presence of multivalents.

5. No confirmation could be obtained of the view that multivalent formation in amphidiploids is a more generally sensitive index of chromosome homology than bivalent formation in the undoubted F1 hybrid. The absence of multivalents in an amphidiploid does not disprove the existence of structural chromosome homologies between the two parents.
A simple climatic chamber for physiological work with poultry
Authors: Hutchinson J. C. D.
Published: March 2009

1. The construction and performance are described of a simple climatic chamber for work on poultry in hot climates. In addition, brief reference is made to an improved ventilation system and to refrigeration equipment fitted to chambers of later design.

2. Air temperature and humidity may be controlled over a fairly wide range above that of the external air. Radiant temperature is maintained close to air temperature. The air movement averages about 20 ft./min. in the working space.

3. The apparatus is suitable for accurate tests of heat tolerance lasting for a few hours, or for longterm experiments.

4. It is suggested that the provision of climatic chambers for use with farm animals in underdeveloped agricultural areas is not a formidable problem.
A Study of genotype-environment interaction in mice
Authors: Young Gilbert B.
Published: March 2009

1. A report is given of an experiment to investigate the extent of genotype-environment interaction in the growth rate and reproductive phenomena of certain strains of mice when kept in two food and two temperature environments. Evidence of interaction was found in both characters.

2. The results are considered to be of sufficient interest to justify further work along these lines.

This might either take the form of extensive studies involving many strains and environments chosen more or less at random, or in more limited investigations where the genotypes and environments are especially chosen because of marked differences.
The nutritive value of roughages for sheep I. The relationship between the gross digestible energy and the chemical composition of hays
Authors: Walker D. M. , Hepburn W. R.
Published: March 2009

1. The relationship existing between the gross digestible energy content and the chemical composition of 24 hays has been studied with nine Cheviot wether lambs over a period of 8 months.

2. Each hay was fed to a group of three lambs for a 10-day preliminary and 10-day collection period. Faeces and urine were collected in metabolism crates.
A study of three breeds of sheep wintered in four environments
Authors: King J. W. B. , Young G. B.
Published: March 2009

A study has been made of the reactions of three breeds of sheep (Blackface, Cheviot and Wiltshire) to four different environments. Evidence was obtained that these breeds react differently to these different environments. No changes in rank occurred but the Blackfaces grew relatively faster on a good plane of nutrition than the other two breeds. Their wool production on a sample area was also relatively greater, due primarily to an increase in diameter of the non-medullated fibres. These differences indicate fundamental physiological differences in reaction to environment.
Meiotic irregularities in hexaploid oats. III. Further observations on the frequency of univalents and other meiotic irregularities in spring × winter variety hybrids of Avena sativa
Authors: Joshi A. B. , Howard H. W.
Published: March 2009

1. The two spring oat varieties, Argentine and Victory, and the two winter varieties, Grey Winter and Black Winter, have 0.10, 0.07, 1.57 and 0.41% pollen mother cells with irregular meioses respectively.

2. F1Victory x Argentine had 3.43% of irregular meioses, and F1. Grey Winter x Black Winter 1.58%.
The mineral content of air and rain and its importance to agriculture
Authors: Ingham G.
Published: March 2009

1. Evidence, both direct and indirect, has been adduced to prove that the air is sufficient both qualitatively and quantitatively to supply all the nutritional requirements of plants, independently of the soil or soil bacteria.

2. The fertility of an undisturbed soil lies chiefly in the surface inch or two and is due to adsorption of plant nutrients from the air by organic and inorganic colloids, such nutrients being carried down to the roots of the growing crop by rain.
Photoperiodicity in Suffolk sheep
Authors: Hart D. S.
Published: March 2009

1. A gradually decreasing plane of light and increasing plane of darkness is not an essential factor for stimulating the onset of oestrus in sheep.

2. Sheep being short-day breeding animals, a standard and regularly maintained rhythm of short-light and long-dark will stimulate the onset of oestrus.

3. The terms short and long are used in the relative sense only, since their significance is solely a means of supplying the necessary contrast impulse to the pituitary gland.

4. A ratio of 1 part of light to 2 parts or more of dark is sufficient to supply the contrast effect.

5. Oestrous cycles induced by artificial light rhythms appear to be normal in all respects, con forming to the normal intervals between heat periods and associated with the ovulation of normal ova.

6. The anoestrous period varies in depth, and sheep which have just entered it may be brought back into oestrus very much faster than animals which are in deep anoestrum.

7. The milk yield of lactating ewes does not appear to be unduly depressed by the onset of oestrous periods induced by an artificial light-dark rhythm.
Analysis of the breeding records of a herd of pigs
Authors: Braude R. , Clarke P. M. , Mitchell K. G.
Published: March 2009

1. A survey and. statistical analysis of the records of litters born in the N.I.R.D. herd of Large White pigs over a period of 16 years are presented.

2. The mean length of gestation was 114 days for both gilts and sows.

3. The mean numbers of pigs born alive and born dead per litter from gilts, 10·0 and 0·2 respectively, were both significantly smaller than the corresponding figures for sows, 11·8 and O·8. No seasonal differences were found.

4. The mean total losses of pigs from birth to weaning at 8 weeks were 29·5% of pigs born alive. The losses in litters from gilts, 23·0%, were significantly smaller than in litters from sows, 31·0%. The losses during the winter months both for gilts, 32·5%, and for sows, 35·9%, were significantly higher than during the summer months, 19·4% and 26·7% for gilts and sows respectively.

5. Over 50% of the total losses were due to crushing by the dam, 74·1% of the losses from this cause occurring during the first 48 hr. after birth.

6. The mean number of pigs weaned per litter was 8·0. The difference between the number weaned per litter from gilts, 7·7, and per litter from number of pigs was weaned per litter from sows during the summer months, 8·7, than during the winter months, 7·4.

7. There was no significant difference between the number of male and of female pigs weaned.

8. The mean weight at weaning was 29·9 lb., male pigs, 30·3 lb., being significantly heavier than females, 29·51b. Pigs in litters from gilts, 27·81b., were significantly lighter at weaning than those from sows, 30·0 lb., and for both gilts and sows, pigs reared during the summer months, 29·7 and 31·8 lb. respectively, were significantly heavier than those reared during the winter months, 25·9 and 28·2 lb. respectively.
The free amino-acids present in fresh and in fermented marrow stem kale
Authors: Robertson Hamish , Barnett A. John G.
Published: March 2009

1. An investigation has been made into the changes that take place in the free amino-acid pattern when kale-water slurries are allowed to ferment under conditions of (a) aeration, (b) anaerobiasis and (c) partial sterilization with sulphur dioxide.

2. It has been found that, with aerated mixtures, the loss of free amino-acids is virtually complete within 2 weeks, while there is only a slight loss with the anaerobic mixtures. With mixtures containing sulphur dioxide no loss of amino-acids occur.

3. The formation of α-amino butyric acid possibly from threonine has been noted.
Heritability of chick viability in a White Wyandotte flock
Authors: Hale R. W.
Published: March 2009

A short account is given of 7 years' breeding for high and low brooder-house viability in a White Wyandotte flock, in which mortality, to 8 weeks of age in most years, varied from almost 50% in the early years to 10% in the last year (1947). When separate sections of the flock were established, the lowviability section showed consistently greater rearing losses than the high-viability section.

Brooder house viability appeared to have a relatively low additive heritability, when estimated from such of the records as were suitable, the pooled estimate from differences amongst sires' progenies being only about 0·07. There was definite evidence that mortality was affected by the common maternal origin of full sibs, the heritability estimated from differences amongst full-sib progenies of dams mated to the same sire being significantly higher than that estimated from differences amongst the half-sib progenies of the sires.
Studies on the effect of nitrogen fertilizer, row spacing and use of antitranspirants on rapeseed (Brassica campestris) grown under dryland conditions
Authors: Patil B. B. , De Rajat
Published: March 2009

An experiment is desoribed which was conducted for 2 years under dryland conditions of north-west India to evaluate the optimum rate of application of N fertilizer and plant population density for a rapeseed crop. Stomata closing (phenyl mercuric acetate), film forming(Mobileaf) and reflective type (kaolinite) antitranspirants were used to examine their effectson conservation of stored moisture for a possible increased water use efficiency under drylandconditions.

The rapeseed crop responded to N fertilizer and it was profitable to use 53 kg N/ha xinder these conditions. In a drier year a wider row spacing of 60 cm (1·1 x 106 plants/ ha) was significantly better than narrower spacing of 30 cm (2·2 xlO5 plants/ha). Plants grown in wider row spacings utilized less water during the vegetative and flowering stages than those grown in closer spacings.

The relative water content of leaves sprayed with antitranspirants was greater than in the control plants. The leaf temperature of the kaolinite-treated canopy was 1·5 °C lower than the ambient air temperature. Averaged over 2 years, the film-forming antitranspirant Mobileaf increased the seed yield by 26% while spraying with phenyl mercuric acetate at 50 and 75 days and kaolin application at 50 days increased the rapeseed yield by 11, 18 and 17% over the no antitranspirant treatment.
Dry-matter content, leaf water potential and digestibility of three grasses in the early stages of regrowth after defoliation with and without applied nitrogen
Authors: Wilman D. , Wright P. T.
Published: March 2009

The regrowth of Aberystwyth S. 22 Italian ryegrass, S. 24 perennial ryegrass and S. 37 cocksfoot was studied in field swards with and without applied nitrogen during the 21 days following a cut or grazing, there being a total of five periods of study at different times of year and in different years.

The dry-matter content of the harvested herbage deoreased by 4–8 percentage units on average from day 6 to day 18 of regrowth, supporting the evidence of earlier experiments with ryegrass and suggesting that a decrease at about this stage is typical. In the present experiments the same trend was evident after removal of surface moisture. Dry-matter content before removal of surface moisture was sometimes as low as 10%, which could adversely affect animal production. The water potential of fully expanded leaf blades was typically more negative on days 2 and 5 of regrowth than subsequently, so that the moderately high dry-matter content during the first week of regrowth seems to indicate some degree of moisture stress. Emerging leaves were less stressed than fully expanded ones during the very early stages of regrowth. Leaf water potential tended to be rather less negative in the cooksfoot than in the ryegrasses. The application of N reduced dry-matter content, but did not affect leaf water potential.

The digestibility of the harvested herbage was little affected by the stage of regrowth. The cocksfoot was less digestible than the ryegrasses. The application of N generally increased digestibility, particularly in cocksfoot.
The proportions of cell content, nitrogen, nitrate-nitrogen and water-soluble carbohydrate in three grasses in the early stages of regrowth after defoliation with and without applied nitrogen
Authors: Wilman D. , Wright P. T.
Published: March 2009

The regrowth of Aberystwyth S. 22 Italian ryegrass, S. 24 perennial ryegrass and S. 37 cocksfoot was studied in field swards with and without applied nitrogen during the 21 days following a cut or grazing, there being a total of five periods of study at different tunes of year and in different years.

The proportion of cell content in the harvested herbage, as measured by neutral detergent, increased by nearly 9 percentage units from day 3 to day 18 of regrowth. The proportion of cell content as measured by acid pepsin also increased during regrowth, but to a lesser extent. The proportion of cell content in leaf blades of two age categories, as measured by neutral detergent, also increased during regrowth. The above increases in proportion of cell content were found in all three grasses. The increases were associated with increases in the proportion of crude protein in dry matter, which were only partially offset by reductions in the proportion of water-soluble carbohydrate. The broad pattern of change in N and nitrate-N content of Italian ryegrass herbage during regrowth in spring with different amounts of N applied, noted in earlier experiments, was confirmed and found to apply to perennial ryegrass and cocksfoot also. During a September-October period of study there was little sign of decline in nitrate-N content within the 21 days where N had been applied. Younger leaf blades had a rather lower nitrate-N content and a slightly higher total N content, on average, than, older blades. The application of N increased the proportion of crude protein more than it reduced the proportion of water-soluble carbohydrate and it increased the proportion of cell content. The increase in proportion of cell content was sufficient to explain the positive effect of N application on digestibility. The average proportion of total herbage N which was found in the cell wall fraction was about 12%.

There appeared to be a relationship between chemical composition and dry-matter content. The chlorophyll content of leaf blades increased during regrowth and was increased by N application. The experimental results on balance, particularly those for proportion of cell content, suggest an improvement in nutritive value of grass during regrowth up to about 3 weeks in contrast to the well-recognized decline in nutritive value where regrowth proceeds beyond about 3 weeks.
Effects of previous legume and oat crops on grain yield and take-all in spring barley
Authors: Dyke G. V. , Slope D. B.
Published: March 2009

Two experiments compared yields of spring barley following barley, oats, beans (Vicia faba), red clover (cut) and (one experiment only) oil-seed rape, and tested effects of trefoil (Medicago lupulina) undersown in the preliminary crops of barley and oats. N fertilizer was applied at two rates to preliminary crops, and four rates to the final crop in each experiment. Barley following barley suffered severely from take-all disease (Gaeumannomyces graminis var. tritici); barley after other crops was little affected. Other recognized soil-borne diseases were unimportant. Barley yielded less after barley than after other crops except where excessive N fertilizer caused lodging. Clover and beans left N residues equivalent to about 88 and 44 kg fertilizer N/ha respectively; undersown trefoil left inconsistent N residues. Couchgrass (Agropyron repens) was more prevalent after barley than after other crops.
Fertility of heifers and suckled cows inseminated at predetermined intervals after treatment with prostaglandin F2α
Authors: Hafs H. D. , Manns J. G. , Wood P. D. P.
Published: March 2009

Heifers and suckled cows in 34 herds were included in a field trial using prostaglandin F2α (PGF2α) to control ovulation. Oestrus was induced by two intramuscular injections of PGF2α 10–12 days apart in 592 animals. Of these, 264 were inseminated once at 80 h and 328 were inseminated twice, at 70 and 88 h, after the second injection of PGF2α. Pregnanoy was confirmed by palpation or by calving without further insemination. After adjustment for independent sources of variation in fertility, estimated true pregnancy rates were 59·6 ± 3·0% for cattle inseminated once, and 61·3 ± 2·7% for those inseminated twice at one oestrus, compared with 66·4 ± 3·2% for 220 animals allowed to cycle normally in the same herds (controls).

In a sub-sample of 538 animals, semen usage was 15% higher for the treated group inseminated once and 107% higher for the group inseminated twice, than for the controls. The breeding season extended over about 80 days for the control groups, and about 30 days for the treated groups.

No side effects attributable to prostaglandin were observed among the treated cattle.
A further study of the effect of sulphanilamide on the metabolism of calcium and phosphorus in the laying hen
Authors: Tyler C.
Published: March 2009

An experiment has been performed on the effect of sulphanilamide on the calcium and phosphorus metabolism of laying hens.

The results showed a decrease in calcium retention and thinner shelled eggs, when sulphanilamide was fed.

When the drug was withdrawn the birds took some time to reach normal balance values again, but they immediately produced normally shelled eggs.

The results of this experiment, along with a previous experiment, have been considered from other points of view in an attempt to find an explanation of some slightly divergent results. Relationships between calcium retained and calcium in shell and between calcium balance and phosphorus balance have been found and the values for changes in calcium bound to phosphorus and residual calcium in bone have been calculated. These considerations have helped to clear up the discrepancies, and it would appear that sulphanilamide effects may be influenced by season, and by calcium and phosphorus intake.
Water conduction by severed grass roots
Authors: Emerson W. W.
Published: March 2009

It is suggested that part of the increased permeability of soil recently ploughed out from grass could be due to water conduction through the severed roots. Microtome sectioning of a root of Lolium perenne showed a continuous metaxylem element of about 30μ diameter, with only minor restrictions, forming a natural capillary tube. Further, being at the centre of the stele, the metaxylem should persist for some time after the grass has been killed. Hydraulic diameters calculated from laboratory experiments on the rates of water conduction by severed L. perenne roots were in reasonable agreement with the diameter of the metaxylem measured by direct sectioning.

Similar experiments on Phleum pratense were more difficult to interpret due to the complexity of the metaxylem, the number of elements not being constant along the root. The rate of water conduction by roots of Dactylis glomeratus was found to be small compared with the other grasses, for although having the largest number of elements they are the smallest in size of any grass examined.

The permeability of a severed Lolium perenne root system, calculated on the basis of the surface density of roots found on 4-year-old plots, indicated that the root system should significantly increase the unsaturated permeability of soil at low suctions. To obtain maximum benefit the ‘capillary tubes’ should be severed immediately under the turf and not at ploughing depth. Accordingly, two plots were laid out on old grassland to compare normal autumn ploughing with shallow rototilling on the subsequent germination and growth of spring wheat. In spite of repeated rototilling, however, it proved impossible to kill the grass in the wet winter conditions and the wheat was smothered. A comparison of the suctions developed at 5 cm. in the two plots showed that the unsaturated permeability of the rototilled plot was higher.

Although the laboratory results are encouraging there is as yet no conclusive evidence that the natural water supply and drainage system formed by the severed roots is important under field conditions.
Seasonal fleece changes in some Cheviot sheep
Authors: Ryder M. L.
Published: March 2009

Two groups of five and six ewes were studied through two separate winters by monthly wool and skin samples in an attempt to follow the changes leading up to fleece casting, which occurred extensively in only two animals.

Although no fleece break was observed, the animals that cast most showed the biggest decrease in fibre diameter. They also had a decrease in staple length where the wool was not cast.

Follicle inactivity increased during the observations reaching a peak at the end of the winter, and the animals that cast most had most follicle inactivity. It is concluded that casting was associated not with fleece break but with increased follicle inactivity coupled with premature release of the fibres from the follicles.
The contribution of seed survival to yield in new Australian cultivars of oil-seed rape (Brassica napus)
Authors: Mendham N. J. , Russell J. , Buzza G. C.
Published: March 2009

A series of experiments in Tasmania examined the growth, development, yield and components of yield of new Australian oil-seed rape cultivars from Victoria and Western Australia. The highest yields obtained were around 5·5 t seed/ha, from an autumn sowing with supplementary irrigation. Spring sowings with irrigation or autumn sowings without produced up to 4 t/ha. The Victorian lines with Japanese parentage clearly outyielded the Western Australian cultivars or Midas, a widely grown Canadian cultivar. When autumn sown, the Victorian lines grew more rapidly at low temperature, which under conditions of later stress contributed to a high yield relative to the other cultivars. However, the most consistent feature from both autumn and spring sowing was high rates of seed survival, up to near the potential number of around 30 per pod, giving very large numbers of seeds per m2. While individual seeds in the Victorian lines, particularly Marnoo, were smaller than in Midas, oil content remained high except under extreme stress in the later stages of seed development.
Further experiments on the drifting of honey-bees
Authors: Free J. B. , Spencer-Booth Yvette
Published: March 2009

1. Worker bees learnt the colour of their hive in the close vicinity to their hive entrance and took little or no notice of colours above the lower brood chamber. They orientated to a colour below the entrance more than to a colour above. They did not learn combinations of colours.

2. They distinguished between certain symbols placed immediately above the hive entrance.

3. They learnt the height of their hive and the height of its entrance above ground.

4. More worker bees and drones from queenright colonies drifted to queenless than to queenright colonies. Drones expelled from queenright colonies did not drift to queenless colonies.
White clover investigations I. Effect of seed rates and cutting treatments on flower formation and yield of seed
Authors: Zaleski A.
Published: March 2009

Investigations on the effect of seed rates and cutting treatments on the inflorescence formations and yield of seed were carried out on S. 100, S. 184 and Kent wild white clover during 1957–60 at Cambridge. The study of primordial development under field conditions, establishment of the major characters contributing to the final yield and the factors affecting their contribution were the main object of these investigations.

These factors and their relationship and contribution to the final yield results are discussed in some detail.
Urea as a fertilizer Laboratory and pot-culture studies
Authors: Low A. J. , Piper F. J.
Published: March 2009

A laboratory and pot-culture investigation to seek reasons for the variable response of grass and other crops to top-dressings of urea, and to the occasional phytotoxicity to seedlings of urea either mixed in the soil or drilled in contact with the seeds is described.

The part played by biuret, the chief impurity in commercial urea, has been examined. It can be phytotoxic to germinating seedlings when in contact, but in the quantities likely to be applied in agriculture in top-dressings, e.g. 150 lb. of urea with up to 2·5% of biuret, its effect is negligible. Up to at least 5% of biuret can be present in urea without affecting its ammonification or nitrification in soil.

It has been shown that loss of nitrogen to the atmosphere can account for the poorer responses of grassland to top-dressings of urea as compared with ‘Nitro-Chalk’ or ammonium sulphate.

The phytotoxic behaviour of pure urea to germinating seeds seems to be due to rapid production of ammonia. This gas is also evolved from topdressings of urea. Both the phytotoxicity and the loss to the atmosphere can be reduced by mixing urea with acid salts to neutralize the ammonia.
The rumen fermentation of lactose in the adult sheep
Authors: Walker D. M. , Lee Barbara A.
Published: March 2009

1. A cross-bred sheep was fed successively with supplements of dried skim-milk or lactose. The effect of the supplements on the lactase activity of the rumen liquid was followed.

2. Lactase activity was expressed as mg. lactose hydrolysed per ml. rumen liquid, or per mg. protein nitrogen. The enzymic activity fluctuated considerably after a change in the diet, and did not become constant even when the ration remained the same for 7 weeks.
The influence of different daylengths on ear emergence and seed setting in oats
Authors: Griffiths D. J.
Published: March 2009

1. The study of the photoperiodic responses of varieties and forms of the genus Avena has revealed considerable diversity within the group.

2. The investigation of a number of forms differing in geographical distribution confirms the close relationship between photoperiodism and region of origin. There appears to exist a definite relationship between the geographic origin of a given form and the limits of its tolerance to short day. The forms from the more southerly latitudes suffered less from short day than those of northern origin.

3. Panicle exsertion was entirely suppressed under photoperiods of 12 hr. and less in A. sativa varieties Victory, S. 84 and Black Supreme, which have been selected for high yielding ability in more northerly latitudes.

4. Plants which failed to produce exserted panicles in varietal tests were dissected, and it was found that floral differentiation had not been inhibited by the shortened photoperiods, but that the full elongation of the internodes, especially the upper internodes, had been suppressed.

5. Selection experiments with progenies of the cross Wintok × A.fatna form Cc 3872 grown under different photoperiods confirmed a highly selective response to daylength, thus indicating that this response is under genetic control.
The effect of a submaintenance diet on the composition of the pig
Authors: Pomeroy R. W.
Published: March 2009

Five inbred Large Whites from the same strain as used by McMeekan (1940) were reared on a High Plane of nutrition to approximately 330 lb. live weight at which one was killed as a control. The rest were put on to a submaintenance diet of straw and water and killed successively at roughly equal intervals in live weight between 330 and 200 lb. The weights of blood, organs and offals were determined and the carcasses were jointed and completely dissected into their constituent tissues. The total weights of each and the weights within the various joints were recorded.

(1)Organs. The early-maturing organs, brain, eyes, etc., continued to grow. Other organs like the heart, liver, lungs, etc., suffered a greater or less degree of atrophy which was probably determined by a suspension of their functions.

(2)Carcass composition. The tissues of the carcass were affected in reverse order to their development, i.e. fat most, muscle less and bone least. Bone continued to grow in the earlier stages of submaintenance.
Drainage and evaporation from fallow soil at Rothamsted
Authors: Penman H. L. , Schofield R. K.
Published: March 2009

1. Study of the automatic records shows:

(a) There is a seasonal change in the drainage response after rain which can be almost wholly ascribed to viscosity changes arising from seasonal changes of soil temperature (p. 77).

(b) Evaporation occurring after a fall of rain has no measurable effect on the drainage response to that rain (pp. 78, 87).

(c) The maximum drainage rates for the 20 in. gauge are much larger than those for the deeper gauges. The maxima change seasonally and are again primarily dependent on viscosity (p. 78).

(d) There is no marked change in the field capacity of the gauge during the year. The air-filled pore space at field capacity may change by about 15% of its average value (p. 81).
The relation of drainage to rainfall and other meteorological factors
Authors: Sahni P. N.
Published: March 2009

Natural drainage periods, i.e. periods between consecutive cessations of flow of the Rothamsted 20 in. drain gauge, were selected for the months of June, July and August. All periods of from 2 to 13 days were taken.

A curvilinear relationship between the difference of rainfall and drainage (deficit) and rainfall was established.

Residuals from this curve showed no appreciable correlation with the mean air temperature, but there was some slight evidence that the deficit was increased by a decrease in relative humidity or an increase in wind velocity.

The residuals showed little correlation with drainage during the previous 3 weeks.
Population studies with wheat: III. Seed rates in nursery trials and field plots
Authors: Hudson H. G.
Published: March 2009

The discrepancies between nursery plots and field plots, found by previous workers when investigating yield problems with wheat, are discussed. The reason for these differences is given, and the true optimum plant density identified.

It is shown that the intensity of competition for water and soil nutriments influences the optimum plant density, and that a high intensity of competition is associated with a low optimum plant density. A summary of literature is given, and the varying values for the optimum seed rates in different parts of the world interpreted in the light of water and soil nutriment supplies.
Studies on the excretion of copper in the rabbit
Authors: Eden A.
Published: March 2009

1. In metabolism experiments undertaken to study the channels of elimination of copper under varying conditions, the rabbit was chosen as experimental animal for convenience of manipulation. This choice, although not defeating the main objects of the work, accidentally added valuable informationon the little-known habit of “physiological faecal refection”in this animal.

2. On a normal diet of bran and oats, containing the usual traces of copper, the rabbit is in copper equilibrium, excreting as much in faeces and urine as is taken in the food. Urinary elimination is of the order of 0·07–0·38 mg. per litre, but this is very subsidiary to faecal elimination of about 2·5 mg. per 100 g. of dry matter, which may account for even more than 96 % of the total food copper.

3. Increase of food copper is not reflected by material increase of urinary output, the higher quantities appearing almost entirely in the faeces. Of 50 mg. of copper or nearly 200 times the normal food intake, as the dissolved sulphate dried on to the food, only 0·1 mg. appeared in the urine, the remainder being slowly excreted in the faeces over the unexpectedly long period of 4 or 5 weeks.
Dissolved organic and inorganic phosphorus compounds in pig slurry: effect of drying
Authors: Gerritse R. G. , Eksteen R.
Published: March 2009

From gel filtration studies it has been found that more than 50% of organic phosphorus dissolved in pig slurry is contained in compounds of high molecular weight. Various ions, e.g. calcium, copper, orthophosphate, are bound by these compounds. From the purine and pyrimidine base composition and resistance to acid and alkali treatment it follows that these organic compounds probably are complexes derived from polydeoxyribonucleotides (DNA).

The effect of drying pig slurry at various temperatures (0–100 °C) on the solubility of phosphorus, calcium and copper after redispersion of the dried slurry was investigated. The solubility of organic phosphorus was not affected by drying and redispersion in water, but the amount of phosphorus contained in dissolved organic molecules of high molecular weight decreased on drying at higher temperatures. The solubility of copper was also not affected by heat treatment. The solubility of inorganic phosphorus is mainly related to the solubility constants of mineral phosphates. On the other hand the total solubility of the cations involved is determined by complex formation.
Using Suffolk sheep for improving lamb production from sub-tropical Egyptian sheep:2. Lamb and fattening performance
Authors: El-Shobokshy A. S. , Aboul-Naga A. M.
Published: March 2009

Lamb and fattening performance and carcass quality of Suffolk x local Ossimi cross-bred lambs are discussed. 1369 cross-bred lamb records over the period from 1957 to 1970 were available for the study. The lambs of 50–59% Suffolk were the best cross-bred group with an advantage of 7–7, 14–2 and 17–1% over the native Ossimi lambs in birth weight, 120-day and yearling body weights, respectively. Generally, lamb performance declined as the Suffolk breeding was increased. However, breed groups variation was not statistically significant, except for birth weight.

Seventy-one weaned male lambs, 4 months of age, from three breed groups: 70–90% Suffolk, 35–45% Suffolk and local Ossimi, were fattened for 16 weeks using two levels of feeding. The two Suffolk cross-bred groups gained slightly more body weight than the local Ossimi. After 8 weeks of fattening, the 35–45% Suffolk lambs gained significantly more weight than the local lambs. However, the local lambs were more efficient in converting food to live-weight gain.

The carcass quality of the Suffolk cross-bred lambs was better than the local lambs, and the advantage was greater for the high Suffolk breeding group.
A field study of coat shedding in cattle under conditions of equal day-length but different temperatures
Authors: Murray D. M.
Published: March 2009

A comparison has been made over 2 years of spring shedding in cattle maintained in two environments experiencing a similar photoperiod but vastly different seasonal temperatures. At each location (Walcha and Narrabi, N.S.W.) experimental animals were divided into two nutritional groups, namely a Feed group and a Pasture group.

2. In 1961-62 both the Feed and Pasture groups in the warmer climate of Narrabri shed their winter coats in October, while animals maintained under the cooler conditions of Walcha did not acquire their summer coats until January of the following year. The Narrabri groups, however, also displayed superior live-weight gains than the corresponding groups exposed to the more severe winter conditions prevailing at Walcha.

3. The following year (1962-63) a differential feeding programme was adopted for the two Feed groups which resulted in their live-weight gains for the experiment being similar. Although the low ration of hay fed to the Narrabri Feed group to achieve this parity of weight gains introduced a nutritional stress factor in the group, these animals displayed a slightly superior shedding ability than did those in the Walcha Feed group.
The response of a rye-grass/white clover sward to various irrigation régimes
Authors: Stiles W. , Williams T. E.
Published: March 2009

A variety of irrigation régimes were applied to a rye-grass/white clover sward, at several nitrogen levels, in small-plot field experiments.

Herbage yields increased with decreasing soil moisture deficit.

No outstandingly good irrigation régime was found, but some distinctly poor practices were identified, by reference to the yield per unit of irrigation water and to the shape of the annual growth curve. The significance of the results for irrigation practice is discussed.

Tho authors wish to thank Dr William Davies for the provision of facilities, Mr R. J. Canaway and his staff who made the irrigation apparatus, many past and present colleagues who helped with the field work, and members of the Biometrics Department who analysed the data.