bluuebunny/crossref_metadata_2025 huggingface dataset:
Establishment of wheat in relation to apparent density of the surface soil
Authors: Millington RJ
Published: November 2004

Measurements were made of wheat establishment and of the apparent density of surface soil on a number of rotation plots at the Waite Agricultural Research Institute. The red-brown earth of the site is common to a large part of the wheat belt of South Australia; this soil shows marked structural deterioration under a variety of cropping systems. Observations made in 1954, 1955, and 1956 provided data on the interaction between the apparent density of the surface soil and the rainfall following seeding, in relation to the establishment of wheat. The apparent density of the surface soil of all rotations varied from season to season and was higher during wetter seasons. Within each season, apparent density was higher on closer rotations and least where wheat was sown direct onto ploughed pasture. Establishment was reduced both by high rainfall and by high apparent density; the latter varied with both rotation pretreatment and current rainfall. It is believed that poor soil aeration resulted either directly or indirectly in reduction in wheat establishment.
Growth and chemical composition of white clover as affected by sulphur supply
Authors: Spencer K
Published: November 2004

Plants of white clover (Trifolium repens L. var. Ladino) were grown in sand culture with four levels of sulphur supply. Growth increased with increasing sulphur supply, all plants except those at the highest sulphur level showing deficiency symptoms. As the severity of the deficiency increased, the root system formed a proportionately larger part of the plant, and the stems and petioles smaller proportions; the proportion of the whole plant formed by the laminae was reduced to only a slight extent. Nitrogen and sulphur fractions were examined in the laminae, nitrogen at each of three harvests and sulphur at the second harvest. The percentages of protein nitrogen and of total nitrogen increased as sulphur supply increased, protein nitrogen forming a greater proportion of the total nitrogen at the higher sulphur levels. In contrast, protein sulphur formed the bulk of the total sulphur in deficient plants, but as sulphur supply approached an adequate level for growth, there was a marked increase in non-protein organic sulphur and a smaller increase in sulphate sulphur. In this respect, white clover appears to differ from legumes other than Trifolium spp. and from non-legumes, all of which accumulate sulphur mainly as sulphate.
Ruminal flora studies in the sheep. IX. The effect of pH on the ciliate population of the rumen in vivo
Authors: Purser DB , Moir RJ
Published: November 2004

Daily infusion of 7, 35, and 70 g of glucose m solution (1, 5, and 10 per cent. of the ration) into the rumen of Merino sheep maintained on an adequate diet resulted in the ruminal pH falling 2–4 hr after feeding, from a mean of 5.66 without added glucose to 5.40 at the higher glucose levels. The concentration of ammonia also decreased, whereas that of volatile fatty acids increased. At the 10 per cent. glucose level, food intake was depressed and the ruminal pH in this treatment did not fall below that at the 5 per cent. glucose level. A significant daily fall in the ruminal pH minima was found during the 3-day sampling period. No consistently significant differences in the concentration of ciliate Protozoa were found at four different sites in the rumen, either before or 1 hr after feeding, although there were significant differences between sheep. Samples taken from the bottom of the rumen immediately inferior to the ruminal cannula, before feeding and 1, 2, 4, 6, 8, 12, and 16 hr after feeding, showed: (a) Only oligotrichs in the ciliate population; (b) Marked diurnal fluctuation in the ciliate population, the concentration after feeding falling to as low
as one-third of the prefeeding levels; (c) A diurnal cycle for dividing Protozoa which indicated that their capacity to multiply was strongly inhibited by the low pH experienced 2–4 hr after feeding. A depression of the average ciliate concentration daily during the 3-day sampling period was also demonstrated. This was related to a consistent but inexplicable fall in the daily ruminal pH minima over this period. It was concluded that the minimum pH within the rumen is an important factor controlling rumen protozoal concentrations in the sheep, and the need for cognizance of this phenomenon in studies of rumen Protozoa is stressed.
Changes in the nitrogen content and pH of the mobilong clay as influenced by land use
Authors: Russell JS , Harvey DL
Published: November 2004

The surface horizons of 40 profiles of the Mobilong clay hare been analysed for total nitrogen and pH, and the analyses compared with similar ones made in 1929. Soils which were originally high in nitrogen have declined, those with medium levels hare remained substantially the same, arid those which were originally low have increased in nitrogen content. The Mobilong clay thus appears to be approaching an equilibrium nitrogen content which under the present land use pattern of irrigation, drainage, and management approximates to 0.50 per cent. nitrogen. It seems probable that further declines will occur in the nitrogen content of those soils which are greatly in excess of this value, though at a slower rate than formerly. On the other hand increases in the nitrogen content of those soils with values less than this should occur. The implications of these changes, both in relation to future land use practices and in relation to general concepts regarding the effect of grass-legume pastures on soil nitrogen levels, are discussed. Changes in pH were found to ha essentially in inverse relation to the changes in nitrogen. Thus soils which have decreased in organic nitrogen have increased in pH, and vice versa. The probable effect of flooding and subsequent deposition on long term changes in the Mobilong clay is discussed.
Relationship of milk production to number of lambs born or suckled
Authors: Alexander G , Davies HL
Published: November 2004

Two independent sets of data, obtained by two different methods of measuring milk production, show that milk yield is greatly influenced by the number of lambs suckled but not by the number of lambs born.
The numbers and distribution of ammonia-oxidizing bacteria in some Northern Territory and South Australian soils
Authors: Sims CM , Collins FM
Published: November 2004

Ammonia-oxidizing bacteria were detected in 75 soil samples from the Northern Territory and South Australia. Silica gel plates gave soil counts comparable with those obtained in liquid media. The counts varied from 20 to 8000 cells per gram of soil. Nitrosogloea merismoides was detected in 53 of the soils, Nitrosornonas europaea in 39 soils, and Nitrosococcus nitrosus in 14 soils. There was little difference between the numbers and types of nitrifying bacteria present in the desert soils compared with those from the more temperate areas, nor did the average annual rainfall have any appreciable effect.
Studies on salt tolerance of sheep
Authors: Peirce AW
Published: November 2004

Six groups, each of six sheep, were fed in pens for 15 months on a ration of chaffed lucerne and wheaten hays. One group was offered rain-water to drink, another group was offered 1.30 per cent. sodium chloride, whereas the others were offered one of the following mixtures of sodium chloride and sodium sulphate: 1.22 + 0.10 , 1.14 + 0.20, 1.05 + 0.30, and 0.89 + 0.50 per cent. The intake of water containing 1.30 per cent. sodium chloride alone, or 0.10 or 0.50 per cent. sodium sulphate with sodium chloride, was higher than that of rain-water, and the intake was increased still further with 0.20 and 0.30 per cent. sodium sulphate; the mean daily intakes for the entire experiment by the six groups were 2.3, 3.8, 3, 6, 4.3, 4.2, and 3.71. respectively. The intake also increased in ell groups with temperature, being 30-60 per cent. higher in the hottest months than in the coldest months. The saline drinking waters had no effect on the concentrations of sodium, potassium, calcium, magnesium, or chloride in the blood plasma. Sulphate, however, was significantly higher, throughout a considerable portion of the experiment, in the plasma of the sheep which received either 0.30 or 0.50 per cent. sodium sulphate. None of the saline solutions used in the experiment had any adverse effect on the general health, food consumption, weight increase, or wool production of the sheep.
Analysis of coat characters of cattle
Authors: Schleger AV , Turner HG
Published: November 2004

Various attributes of cattle coats are evaluated in terms of their repeatability and heritability, and their capacity to discriminate between coats of different breeds, but principally in terms of their correlations with a subjective coat score, with skin temperature, and with growth rate. The correlation of 0.7 between growth rate and coat score is almost equalled by the multiple correlation between growth rate and a group of measured coat characters. Of these objective characters contributing to coat type, the depth of coat and the hair diameter are most important, followed by the percentage of medullated hairs and the maximum length of fine hairs; hair curvature and follicle angle contribute little. Bonsma's felting score provides a useful indication of coat type, but it is consistently inferior to a coat score. Weight of hair per unit area of skin is unreliable, because it is dependent on length and diameter, which have opposing effects on coat quality. The relative value of different characters varies with circumstances. In late spring, depth was the most important measurement but in winter and early spring it was exceeded in importance by a score of the amount of "body" in the coat. Though coat score is defined fairly completely in terms of component characters, it remains of greater value than any other assessment, presumably because it refers to the whole coat in situ, rather than to a small sample of clipped hair.
A comparison of several procedures for estimating the sulphur status on soils
Authors: Spencer K , Freney JR
Published: November 2004

The sulphur status of a number of soils was determined by several laboratory procedures. The chemical procedure which extracted amounts of sulphur showing the most satisfactory correlation with the sulphur-supplying ability of the soils (as measured by plant growth) was an extraction of the soil with a potassium dihydrogen phosphate solution containing 500 p.p.m. phosphorus. The superiority of this procedure over the other extraction procedures tested (cold-water extraction, hot-water extraction, acetate extraction, and Williams and Steinbergs's heat-soluble method) probably lies in its ability to displace adsorbed sulphate. The sulphate which was extractable by the phosphate solution was found to have decreased after cropping, by an amount which was closely related to, but not of the same order as, the sulphur taken up by the plants. The difference (uptake minus decrement), which represents the net mineralized sulphur, was small relative to the amounts of extractable sulphate initially present. Microbiological assay using Aspergillus niger was an equally reliable method for assessing sulphur status and had the advantage of simplicity. Except in two brigalow soils, the sulphur obtained by Aspergillus was very similar to that extracted by phosphate, which suggests that Aspergillus is able to obtain adsorbed sulphate.
A study of dormancy, survival and other characteristics in Lolium perenne L. at Adelaide, S.A.
Authors: Silsbury JH
Published: November 2004

A collection of perennial ryegrass from the Mediterranean area has been grown as spaced plants at Adelaide since 1956. Morphological characteristics, time of heading, summer dormancy, and persistency have been recorded and have been used to describe three distinct plant types. These new types are more persistent at Adelaide than existing commercial cultivars, high summer survival being attributed to the occurrence of summer dormancy. The importance of the collection as a source of new genotypes is stressed.
Peanut plants in Queensland infected with tomato spotted wilt virus
Authors: Helms K , Grylls NE , Purss GS
Published: November 2004

A disease of peanut (Arachis hypogaea L.) in Queensland, previously referred to as "chlorosis", was identified as being caused by the tomato spotted wilt virus. Symptoms of the disease on peanut are described. Erigeron bonariensis L., Tagetes minuta L., and Trifolium subterraneurn L. are recorded as new hosts. The disease was not seed-transmitted, although seeds developed lesions and were malformed. Infective virus was found in tissues of the integuments of immature seed. The maximum disease incidence recorded in an individual crop was 5.5%. The mean seed yield of diseased plants was 12.7 g per plant, whereas that of healthy plants was 128.2 g.
Nitrogen utilization and wool production by sheep
Authors: Reis PJ , Schinckel PG
Published: November 2004

The utilization of nitrogen was examined in sheep fed several diets; in some experiments the diet was supplemented with soluble casein given directly into the abomasum through a fistula. Casein supplements per abomasum were almost completely digested and absorbed. At the highest level of casein supplementation (55 g casein nitrogen per day) 95% of the casein was digested and absorbed. An increase in nitrogen intake resulted in an immediate increase in nitrogen balance, followed by a gradual return towards a stable level. There was also an immediate response of faecal and urinary nitrogen excretion to a change in nitrogen intake. Most of the adjustment in urinary nitrogen excretion occurred within 4 days, this period being followed by a gradual change towards a stable level of excretion during the next 6 weeks. Much higher levels of nitrogen retention were obtained from casein administered per abomasum than from similar levels of nitrogen given per os. Changes in wool production also occurred following changes in the nitrogen intake per 0s. The observed changes were variable, depending on the sheep and the feed change involved, and periods of up to 10 weeks were required before the rate of wool production became stable following a change in nutrition. Casein supplementation per abomasum resulted in a substantial increase in wool production and in a rapid increase in wool fibre diameter; most of the increase in fibre diameter occurred in the first week of supplementation. The efficiency of conversion of dietary nitrogen into wool nitrogen was much higher in experiments where a casein supplement was administered per abomasum than in experiments involving normal feeding; possible reasons for this difference are discussed.
Relations between yield of wheat, soil factors, and rainfall
Authors: Millington RJ
Published: November 2004

Data have been collected from wheat plots in long-term rotation experiments on a red-brown earth at Adelaide, South Australia. Measurements were made of the apparent density and total nitrogen status of' the surface soil and of seedling establishment. Variation in grain yield, as well as grain yield response to applied nitrogenous fertilizer, was assessed in relation to these factors both within and between seasons. In particular, soil and plant responses to the amount of rainfall occurring just after sowing hare been examined. It has been shown that there are marked seasonal changes in apparent density associated \ d h the mount of rainfall occurring in the month following sowing. These seasonal changes in apparent density are accompanied by a reduction in seedling establishment and a depression of crop grain yield in years of high post-seeding rainfall. The results suggest that a large part of the reduction in yield in excessively wet seasons on unstable soil.; like the red-brown earth may be ascribed to poor physical conditions of the soil, and not predominantly to the leaching of nitrate.
Pharmacology and toxicology of carbon tetrachloride in the sheep. I. Blood levels following ruminal, abomasal, and intramuscular administration
Authors: Kondos AC , McClymont GL
Published: November 2004

Studies are reported on the blood levels of carbon tetrachloride following administration of 8 ml of the drug to sheep by ruminal, abomasal, and intramuscular routes. Absorption was most rapid with ruminal administration, slowest with intramuscular, and intermediate with abomasal administration. The drug could be detected in expired air within 5 min of administration. Peak levels in the blood of c. 16 to 20 pg per ml were reached, with ruminal and abomasal administration, at c. 15-30 min and 60-120 min respectively. With intramuscular administration the peak of c. 10 �g/ml was reached at about 4 hr. Undetectable levels, less than 5 pg/ml, were reached at c. P 5 hr with ruminal administration, 6-7 hr with abomasal administration, and c. 10 hr with intramuscular injection. Carbon tetrachloride could be detected in the expired air up to 40-60 hr after administration, depending on the route. The blood curves were not appreciably different whether the drug was administered in the pure state or in paraffin oil. Fasting for 48 hr also had no appreciable effect. Fat sheep showed lower levels and a longer period of excretion than animals in poorer condition, presumably owing to partitioning into adipose tissues.
Hornedness and polledness in sheep. 4. Triple alleles affecting horn growth in the Merino
Authors: Dolling CHS
Published: November 2004

Three genes have now been identified as affecting horn growth in the Merino. Test matings have shown that these are alleles at one locus, or comprise two pairs of alleles at closely linked loci. The genes are named P, P', and p, and their effects on horn growth in each sex are tabulated.
The relation between tillering and dry matter production in cocksfoot (Dactylis glomerata L.). Grown under spaced and sward conditions.
Authors: Knight R
Published: November 2004

A study of nine clones of cocksfoot (Dactylis glomemta) showed that differences between clones in dry matter production were not associated with tillering ability. The clones, seven of Mediterranean origin and two from Great Britain, were grown under the spacing conditions of a breeding nursery and in swards, but were not defoliated. Individual plant weight and tiller number were greatly reduced by sward conditions, as compared with plants under spaced conditions. Tiller weight was much less affected. Thus the lower individual plant weight in swards was associated mainly with fewer tillers. Tiller numbers in the swards rose to a peak during the second year, followed by a decline to the end of the growing season. The decline, which differed between clones, was related to plant weight and was probably correlated with the mutual shading of the plants.
Studies on nodulation responses to pelleting of subterranean clover seed.
Authors: Thompson JA
Published: November 2004

In a series of field experiments on seven soils of pH 6.0 or higher, nodulation of subterranean clover (Trifolium subterraneum L. var. Tallarook) was improved by pelleting the seed with various glues and coating materials, prior to inoculation with dry peat inoculum. On these soils the responses were not related to the chemical properties of the pellet materials. The beneficial effect was apparently the result of physical separation of the seed coat and inoculum. It is postulated that pelleting of seed protects the inoculum from an antibiotic, whlch has been found in subterranean clover seed coats, and which is active against Rhizobium in culture. On a soil of pH 5.1 a nodulation response to two types of pelleting materials was apparently related to the chemical constituents of the coating materials. In this soil there was less evidence of the importance of physical separation of the inoculum from the seed coat. It seems likely that soils may differ considerably in their ability to inactivate the antibiotic. Nodulation was not improved by in situ fumigation, prior to sowing, of two soils of pH 6.0 and 6.6, which indicated that antagonism by soil microorganisms was not the cause of poor nodulation in these soils. Significant nodulation responses to pelleting were obtained in sowings in these fumigated soils.
The effects of a number of management practices on chiller beef production in Victoria. II. Live measurements
Authors: Robinson TJ , Cameron NG
Published: November 2004

Data are presented from a factorial experiment on the effects of a number of management practices on live measurements of young growing Aberdeen Angus cattle. Sire and dam influenced most measurements, as did supplementary feeding. Season of birth and sex were the two most important factors affecting all body measurements. Year of birth had a slight effect. Correlation coefficients are presented for corresponding measurements of dams and progeny, and for liveweights and measurements at successive ages. Birth weight was highly significantly correlated with weaning and slaughter weights (r = +0.432, +0.504; P<0.001), independent of the sex effect on growth rate. Body measurements at 6 weeks had a fair predictive value for corresponding measurements at 32 weeks (pre-weaning) and 84 weeks (pre-slaughter). The growth curves of heart girth and width of hooks closely paralleled that of liveweight (r = +0.985, -0.982). Length and height measurements were less close, followed by cannon measurements and depth of chest. Width of head and round measurements were least well correlated with weight.Under conditions of nutritional stress, bone growth may continue little impaired, despite loss of liveweight. Birth weights, or weights at a fixed time shortly after birth, could have a useful predictive value in selecting cattle for high weaning weight and post-weaning weight-for-age under southern Australian conditions of husbandry.
Metabolic activities of sheep erythrocytes. I. Glycolytic activities
Authors: Leng RA , Annison EF
Published: November 2004

Sheep erythrocytes, which in most animals are impermeable to glucose, show low glycolytic activities relative to human cells. When 14C-labelled glucose was incubated with erythrocyte suspensions the oxygen uptake was 10.9 ± 1.8 µl/hr/ml of cells (5 replications), and glucose oxidation (measured by recovery of [14C]carbon dioxide) was 0.03 ± 0.007 µmole/hr/ml (5). Addition of methylene blue (0.4 µmole/ ml) increased oxygen uptake to 56 ± 3.5 µl/hr/ml (5) and glucose oxidation to 0.36 ± 0.02 µmole/hr/ml. Lactic acid production was increased from 1 .5 ± 0.06 µmole/hr/ml (7) to 1.7 ± 0.11 µmole/hr/ml (7) in the presence of methylene blue. Comparison of the yields of [14C]carbon dioxide from [1-14C]glucose and uniformly labelled [14C]glucose indicated that when stimulated by methylene blue 80–100% of glycolysis proceeded by the pentose phosphate pathway, but in the unstimulated system the alternative aerobic pathway accounted for only about 15% of total glycolysis.
Temperature regulation in the new-born lamb. V. Summit metabolism
Authors: Alexander G
Published: November 2004

"Summit metabolism" was estimated by measuring respiratory exchange during a 20 min period of falling rectal temperature. The rate of fall was controlled at about 1°C per 20 min, by varying the wind velocity while the lamb was exposed to conditions of high heat loss. At body temperatures near normal, summit metabolism was not predictable from rectal temperature. Below 36°C the metabolic rate was proportional to rectal temperature. When expressed as kilocalories per kilogram per hour, summit metabolism in young lambs was approximately constant at all body weights, and hence summit, metabolism per unit of surface area increased with increasing body weight. Heavy lambs are therefore able to maintain homeothermy under conditions of higher heat loss than light lambs. Summit metabolism was usually established at about 17 kcal kg-1 hr-1 within half an hour of birth, i.e. heat production increased rapidly to 15 times foetal levels or five times "basal" levels. There was no increase after ingestion of milk, and the summit metabolic rate appeared to decline slowly with advancing age. It also declined during prolonged exposure to cold and during prolonged fasting, particularly in very young lambs. Blood analyses indicated a great mobilization of fat and carbohydrate during exposure to conditions which evoked a summit response. The practical significance of these results is discussed.
Genetic variation in the effictiveness of nodulation of lucerne varieties
Authors: Gibson AH
Published: November 2004

The effectiveness of the nodulation of 15 varieties of lucerne, inoculated with single strains of Rhizobium meliloti of widely differing origin, was examined in test-tube culture under glass-house conditions. The principal findings were that: (i) Some varieties were more effective in their symbiosis with these bacterial strains than others. (ii) Some bacterial strains were generally more effective in their symbiosis with these varieties than others. (iii) Highly significant host variety x bacterial strain interactions required that the generalizations regarding varieties and bacterial strains should be interpreted with caution. The variety Rambler was unable to form an effective symbiosis with any of the Australian strains of Rh. Meliloti tested, although two isolates from nodules of Canadian-grown Rambler plants achieved a reasonable level of effectiveness in their symbiosis with this variety. Considerable variation existed within variety x strain treatments; this variation was greatest in the treatments designated as "intermediate" in their effectiveness of nodulation. The significance of the results is discussed, and a plan for the breeding of legumes, in which nodulation aspects are considered, is suggested.
The growth of some perennial grasses in waterlogged soil. I. The effect of waterlogging on the availability of nitrogen and phosphorus to the plant
Authors: Humphries AW
Published: November 2004

In a greenhouse experiment, nitrogen uptake by young phalaris plants was depressed by soil waterlogging. The effect became more pronounced as the level of application of nitrogen fertilizer was increased. In a second experiment, soil waterlogging had similar effects on the availability of phosphorus to phalaris and perennial veldt grass. The reduction in uptake was much more marked in the latter species. Perennial veldt grass was much less tolerant of waterlogging than phalaris. However, phalaris exhibited adverse reactions unless the soil nutrient status was sufficiently high. The application of these findings to field condition is discussed briefly.
Some consequences of bituminous mulches
Authors: Collis-George N , Davey BG , ScotterD R , Williamson DR
Published: November 2004

The temperature and moisture consequences of bitumen mulching were examined experimentally. Because of its colour and surface contact nature, bitumen behaved dissimilarly to conventional "air blanket" mulches by increasing soil temperatures. Whether in a continuous surface or in a cultivated (broken) and admixed form, bitumen mulches conserved soil moisture. The behaviour of plants was dominated by the soil physical conditions imposed by the bitumen mulch as long as the vegetative cover was small.
The effect of concentration on the performance of two DDT cattle-dipping formulations
Authors: O'Neill DK
Published: November 2004

Dipping trials with two supelcooled melt formulations of DDT, in which the DDT concentrations were raised progressively to four times the usual strength, showed that whilst more DDT was deposited both on the hair of calves and on bush ticks (Haemaphysalis bispinosa Neumann) as the DDT concentration was increased and the dip aged, the toxicity to ticks of both formulations increased only during the early stages of each trial. Clearly the size and shape of the DDT crystals which developed in both dips and the degree of crystal aggregation were important factors which influenced the deposition of DDT and its toxicity. Of the forms of DDT present, the toxicity is attributed mainly to microcrystals of colloidal dimensions. Additions of formulation would serve to maintain but not increase the concentration of these microcrystals. Differences in performance of the dips is ascribed to the composition of the soaps (i.e. surface active agents) in the formulations. The experiments emphasize the importance of the nature of the deposit, and indicate that increases in dip concentration will not necessarily give better biological performance.
An investigation of the Barley Yellow Dwarf Virus as a primary or associated cause of premature ripening or "Deadheads" in wheat
Authors: Price RD , Stubbs LL
Published: November 2004

In two controlled experiments conducted in 1960 and 1961 respectively, the ability of recognized root pathogens to induce premature ripening ("deadheads") of wheat was compared with that of the barley yellow dwarf virus, a hitherto uninvestigated factor in this regard. In both experiments the heads of virus-infected plants ripened earlier than those of plants inoculated with fungal pathogens, and grain in heads which were not completely sterile was extremely shrivelled. However, it was impossible to decide by visual observation when normal ripening commenced. To overcome this difficulty a formula for the classification of prematurely ripened heads, on a weight per floret basis, was used for the statistical analysis of the results. On this quantitative basis it was found that the virus significantly reduced the yield of grain (l% level), but there was no interaction between the virus and any of the root-rot fungi. The fungus, Rhizoctonia solani, Kuehn, also significantly reduced the yield in both experiments (5% level) and Fusarium culmorum (W.G.Sm.) Sacc. caused a reduction (5% level) in the 1960 experiment. There was a significant interaction (5% level) between these fungi in the 1961 experiment. The fungi Ophiobolus graminis Sacc., Helminthosporium sativum Pamm., King & Bakke, and Curvularia ramosa (Bainer) Boed., did not significantly reduce grain yield in either experiment. All fungi were recovered, but to a varying degree, from the roots of inoculated plants.
The effects of temperature on the early vegetative growth of Phalaris canariensis L. and P. tuberosa L.
Authors: Scurfield G
Published: November 2004

Seedlings of Phalaris canariensis and P. tuberosa were grown in pots outdoors and under glass-house conditions in experiments at Canberra. Sigmoid curves expressed the increase in total dry weight, dry weight of plant parts, and tiller number for both species grown outdoors for 5 months. Phase 1 — the vegetative phase of growth — ended on about September 18 for P. canariensis and September 12 for P. tuberosa. Subsequent experiments were concerned with the effects of temperature on this growth phase. In experiments lasting for up to 44 days, both species were grown under natural (winter) conditions of light intensity and day length (less than 12 hr) and 16 combinations of day and night temperature. The optimum regime for dry weight production — 24/18–19°C — did not correspond with that optimal for tiller initiation. Highest tiller numbers were obtained when night temperature exceeded day temperature (19/22° or 19/24°), or approached the optimum day temperature (24/22° or 24/24°), or there was a relatively large fluctuation between day and night temperature (28/18°, for example). P. canariensis outyielded P. tuberosa under optimum temperature conditions, but P. tuberosa appeared to be less sensitive to night temperatures of 22–24°. No consistent trends in the effects of day or night temperature on the nitrogen content of tops, leaf length, leaf breadth, or the ratio leaf length/breadth were obtained. Leaf size and shape were, however, influenced by temperature. A comparison of the growth of the Australian commercial P. tuberosa was made with that of strains from Israel and Algeria under six temperature regimes. Under cold and cool conditions, the Algerian strain resembled the Australian strain, both being outyielded by the Israeli strain. Under a regime of 28/23°, however, the Algerian and Israeli strains were adversely affected, the latter more than the former. In nutrient culture solution, a root temperature of 20° approached the optimum for dry weight production and tiller initiation by P. canariensis more nearly than one of either 12° or 27°, ambient temperature being 24/20°. Leaf size was also influenced by root temperature.
Total salivation in grazing lambs
Authors: Tribe DE , Peel L
Published: November 2004

Recordings were made of the resting secretion rates of total saliva in grazing lambs from 13 to 86 days of age and from 2-year-old grazing wethers. The saliva was collected froin conscious animals by means of an oesophageal fistula. In certain cases the two parotid ducts were temporarily cannulated and separate but simultaneous collections were made of the secretions from the two parotid ducts and of the residual saliva. During the first 4 weeks or life the rate of total salivation by the lambs was extremely low, but it then rapidly increased until by 5 weeks of age they had reached the range of the adult sheep. However, the separate collections from the parotid cannulae and the oesophageal fistulae indicated that the rate of residual secretions had not fully reached adult levels by the time the lambs were 88 days old. In the adults the residual saliva comprised approximately 41% of the total secretion but in the lambs there was only approximately 26% of residual saliva. Analyses of the nitrogen, sodium, and phosphate levels in the samples collected showed that the composition of total saliva did not alter from 32 to 88 days of age, and that the parotid saliva contained less nitrogen and more sodium than the residual saliva.
Effect of pasture availability and shearing stress on herbage intake of grazing sheep
Authors: Wheeler JL , Reardon TF , Lambourne LJ
Published: November 2004

Digestible organic matter (D.O.M.) intakes of sheep grazing various pastures were measured by faecal index methods in three 4- to 6-week experiments. No correlation could be found between the weight of pasture available (over the range 150–2900 Ib dry weight per acre of green herbage) and the D.O.M. intake of sheep. During two experiments the sheep were shorn. Shortly after, voluntary D.O.M. intakes rose significantly by 42–62%. Concurrently the hay intake of other sheep yarded nearby rose by 20–51% following shearing. Cold stress is probably responsible for these increases.
Chemotactic bevaviour of the infective zoospores of Dermatophilus dermatonomus
Authors: Roberts DS
Published: November 2004

When carbon dioxide (CO2) concentration gradients were established experimentally in Dermatophilus dermatonomus cultures and zoospore suspensions, the zoospores showed a chemotactic response by moving towards an optimum CO2 concentration. The characteristic negative aerotaxis of the zoospores was found to be a response to a CO2 concentration gradient resulting from their own CO2 production and the simultaneous loss of CO2 at the air-liquid interface. The zoospores exhibit a negative chemotactic response to toxic electrolytes, as demonstrated by their reaction in suspensions exposed to ammonia, hydrogen chloride, and sulphur dioxide fumes. Oxygen, hydrogen, nitrogen, and defibrinated sheep blood all failed to exert any detectable chemotactic effect. It is deduced that the response of the zoospores to CO2 would facilitate two important steps in the life cycle of D. dermatonomus. The high CO2 concentration, probably produced in wet mycotic dermatitis scabs by the dense populations of zoospores, would accelerate their escape to the exterior, while the respiratory efflux of CO2 from the skin would attract the zoospores to susceptible areas on the skin surface.
Quantitative and morphological variation of sweat glands, skin thickness, and skin shrinkage over various body regions of Sahiwal Zebu and Jersey cattle
Authors: Pan YS
Published: November 2004

By comparison with Jerseys the sweat glands of Sahiwals were 70% longer, 55% wider, and 315% greater in mean volume. Total sweat gland volume per unit area of skin was 340%, greater and skin thickness was 60% greater, but skin shrinkage was 30%, less. The density of sweat glands was 1130/cm2 for Jerseys and 1200/cm2 for Sahiwals. In almost all animals the characters varied significantly between the various body positions, and in most cases showed trends. Values for the generally adopted midside sampling position were usually within 10% of the mean value for all positions. Sweat gland shape varied over the body. Most of the shapes observed in the two species were present in one position or another within each animal.
Selection for fertility in Australian Merino sheep
Authors: Young SSY , Turner HN , Dolling CHS
Published: November 2004

Phenotypic and genetic parameters for fertility in sheep, in terms of number of lambs born and number weaned, have been estimated in a flock of medium Peppin Merinos. Repeatability of fertility traits over all ages is low, but there is an age effect, the record at 3 years of age having a higher value than those at 2 or 4 years. The regression of subsequent performance on a difference of 1 lamb at the initial lambing was higher for the difference between 1 and 2 lambs than between 0 and 1 lamb, which indicated that selection for twins is likely to raise fertility in the current flock more rapidly than selection against barrenness. The estimate of heritability for 2 years of age was negligible for each fertility trait, but the estimates for the 3-year-old record were higher, the value for lambs born being over 0.3. Mass selection for number of lambs born at 3 years of age would thus be expected to lead to appreciable genetic progress, while there would be at least some progress in number of lambs weaned. Phenotypic and genetic correlations were also estimated between fertility at different ages and 10 sheep and wool traits measured at 15–16 months of age. Phenotypically, fertility is positively correlated with body weight and negatively with skin wrinkle score. Genetically, it is suggested from the estimates that fertility is positively correlated with body weight and staple length and negatively correlated with fibre diameter, clean scoured yield, and wrinkle score. No phenotypic or genetic correlation was found between greasy or clean wool weight and either measure of fertility. The application of the findings to breeding for higher fertility is discussed. In an appendix, a maximum likelihood method of estimating heritability for all-or-none traits in half-sib data is presented.
The effect of nutritive status on oestrus, ovulation, and Graafian follicles in Merino ewes
Authors: Lamond DR
Published: November 2004

Progesterone suppression of ovarian cycles and the subsequent "release" phenomena following cessation of injections were examined in three groups of ewes under different nutritional regimens. A significant delay in the period from the final progesterone injection to onset of oestrus occurred in ewes on a restricted diet compared with ewes on a maintenance diet. A strong relationship existed within the restricted group between body weight and the period to onset of oestrus. Gonadotrophin appeared to compensate for the effect of undernutrition.
Copper deficiency symptoms of some tropical and temperate pasture legumes
Authors: Andrew CS
Published: November 2004

Foliar symptoms of copper deficiency shown by five tropical and five temperate pasture legumes are described. The descriptions are sufficiently diverse to permit individual treatment. The more succulent species showed severe chlorosis and necrosis of leaves, whereas the less succulent ones showed chlorosis followed by leaf abscission and little necrosis. Species within a genus developed somewhat similar symptoms. The initial symptoms of copper deficiency in the Trifolium species in particular were wilting and partial dehydration. The implications of copper deficiency on wilting are discussed.
The functional activity and control of the apocrine sweat glands of the scrotum of the ram
Authors: Waites GMH , Voglmayr JK
Published: November 2004

When scrotal skin temperature was raised to above 35.3°C, the large glands of the scrotum discharged sweat synchronously at intervals of 2–14 min in eight rams and 9–40 min in one ram. Evaporation of the sweat when the wool on the scrotum was short caused sharp falls in skin temperature of up to 2.6°C; when wool was 18–30 mm long, skin temperature first rose and then fell to either the pre-discharge temperature or just below. Local anaesthesia of the superior perineal nerves abolished the sweat gland response to heat. Although single intravenous injections of adrenaline (1–4 µg /kg) and noradrenaline (1–6 µg /kg) were followed by single sweat gland discharges, bilateral adrenalectomy with replacement of adrenal cortical hormones did not prevent gland discharges in response to heat. The appearance of the first discharge in the adrenalectomized ram was delayed, and the delay was reduced by constant infusions of 0.8–1.0 µg adrenaline /kg/min. Partial lumbar sympathectomy changed the pattern of discharges and reduced the amount of fluid ejected at each discharge. It is concluded that adrenergic sympathetic nerves control the expulsion of sweat in response to heat, but that hormones from the adrenal medulla may also play a part. The control of sweating by cutaneous temperature receptors and its relationship to the possible control exerted by receptors in the brain are discussed in the light of these findings.
Body composition in vivo. III. The composition of living ruminants and its relation to the tritiated water spaces
Authors: Panaretto BA
Published: November 2004

Two methods for predicting the body composition of living goats from the tritiated water spaces derived in them were proposed previously from results obtained with 11 goats. The relation of tritiated water spaces to body composition has been studied in an addltlonal 10 goats and 9 sheep, and these results together with those previousl y published have yielded a more precise method for calculating the body composition of living ruminants in terms of water, fat, protein, and ash.
The phosphorus content and yield of grain of different wheat varieties in relation to phosphorus deficiency
Authors: Lipsett J
Published: November 2004

Several varieties of Australian and two American bread wheats were grown in the glass-house under conditions of controlled phosphorus deficiency. A wide range of final phosphorus concentrations occurred in the grain of all varieties in response to variations in phosphorus supply. Suffcient phosphorus at sowing raised the value for Australian grain to 0.4% P. Under deficiency conditions, the concentration in all varieties fell below 0.25% P, a typical value for grain from southern Australia. Yields of two Australian varieties, Bencubbin and Charter, were further examined. Variety Bencubbin was shown to give larger grain yields than Charter under conditions of phosphorus deficiency, and its grain had lower concentrations of phosphorus. The higher yields were not associated with higher uptakes of phosphorus. Bencubbin showed a marked luxury uptake in the straw at moderate rates of phosphorus application. It is suggested that the lower phosphorus concentrations in the higher-yielding variety are necessarily associated with success in selection for dry matter yield, where the uptake of the nutrient is limited.
Energetic efficiency of fattening sheep. II. Effects of under-nutrition
Authors: McCGraham N
Published: November 2004

Balances of energy, carbon, and nitrogen were determined with five castrate sheep at several levels of feeding and at fasting, when the sheep were in lean condition and when they were very thin; measurements had been made previously when they were fat. While the animals were on a constant low ration to cause loss of condition, the observations were continued under both thermoneutral and cold conditions, and glucose and ketone levels in the blood were also measured. The digestibility and metabolizability of the gross energy of the food were not affected by body condition. However, as the sheep lost weight, the net availability of metabolizable energy at each level of food intake declined. The change of efficiency was not apparent when comparisons were made at equivalent levels of energy storage. In the weight range 21–59 kg, the fasting heat production varied directly with body weight at a rate of 10 kcall24 hr/kg. Prediction of fasting metabolism from body weight is discussed. Changes of energy utilization were largely accounted for by changes of fat metabolism. When the sheep were emaciated, oxidation of protein during fasting was somewhat greater than when they were fat, but nitrogen supplied by the food was used more efficiently. Under cold stress, the heat production of the sheep increased to a high level, which did not vary with body weight until homeostasis failed when the animals were extremely emaciated. The apparent digestibility of the food (at the lowest intake) decreased by 0.47 unit/°C fall of ambient temperature. While the sheep were on the submaintenance ration, the levels of blood glucose and ketones remained at the higher end of the "normal" range under thermoneutral conditions and were somewhat elevated under cold conditions. Hypoglycaemia occurred only when homeostasis failed.
The buffering capacity of pasture plants with special reference to ensilage
Authors: Greenhill WL
Published: November 2004

The buffering capacity of herbage is of importance in silage making, and studies have been made of ryegrass, clover, and lucerne. Autumn-grown ryegrass was found to be more heavily buffered than the spring- or summer-grown material; with clover and lucerne the spring-grown material was highest. The least mature samples had the highest buffering capacity in every case. Neither time of day nor wilting had any significant effect. Increases in buffering capacity during ensilage were shown to be due largely to the production of lactic and volatile acids. The success of a silage fermentation depends on the rate of acid production being more than able to compensate for the increasing buffering capacity.
Transmission and protective inoculation studies with viruses of the citrus tristeza complex
Authors: Stubbs LL
Published: November 2004

An investigation since 1949 of viruses of the citrus tristeza complex indicated that the association of virulent, yellows, and tristeza-inducing viruses with orange and mandarin and that of avirulent types with grapefruit, lemon, and sour orange is a general but not absolute rule, as some exceptions were noted. Attempts to separate yellows and non-yellows components from a virulent isolate, by applying short and long feed techniques to the vector aphid, Toxoptera citricidus Kirk., were unsuccessful. A comparison of the vector efficiency of 12 clonal lines of T. citricidus aphids revealed different transfer characteristics between clones. However, transmission results from two experiments were inconclusive. Cross-protection experiments were conducted over an 11 year period with seedling trees of grapefruit and sweet and sour orange seedling combinations. In these, mild isolates from grapefruit and lemon differed considerably in initial protective ability. Over a long period, however, even a strain of low initial protective ability exerted a considerable influence, as determined by tree growth. The virulent challenge virus used in these experiments retained its yellows- and tristeza-inducing ability when it was the sole inoculant, but not in trees previously inoculated with a mild isolate. The results of transmission and cross-protection tests are interpreted as evidence that viruses of the tristeza complex are related entities, varying in virulence but rarely if ever existing as pure strains. An explanation of host-reaction phenomena in terms of the combined effect of host selectivity of strains and mutual interference between tristeza variants is discussed.