bluuebunny/crossref_metadata_2025 huggingface dataset:
The contribution of maternal environment and lamb genotype to growth of lambs from Merino, Poll Dorset × Merino and Border Leicester × Merino ewes
Authors: Kleemann DO , Dolling CHS , Ponzoni RW
Published: November 2004

Suffolk-sired lambs from Merino, Border Leicester x Merino and Poll Dorset x Merino dams were either mothered to ewes of their own breed of dam or to ewes of one of the other breeds of dam, with the exception that lambs born from Border Leicester x Merino, and Poll Dorset x Merino dams were not fostered between Border Leicester x Merino and Poll Dorset x Merino breeds of dam. Liveweight and lucerne meal consumption of the lambs and milk yields of the dams were determined during the first 100 days of lactation. Lambs reared by Border Leicester x Merino dams were significantly heavier than those reared by Merino dams at 16 and 23 days of age. They maintained this advantage throughout lactation, though differences were not statistically significant. There were no significant differences in liveweight of lambs between Poll Dorset x Merino and Merino dams. Suffolk x (Border Leicester x Merino) lambs were significantly heavier than Suffolk x Merino lambs at birth and when 9 days of age. They maintained this advantage throughout lactation, though the differences were not significant. Suffolk x (Border Leicester x Merino) lambs were also significantly heavier at birth than Suffolk x (Poll Dorset x Merino) lambs. However, the difference decreased with age so that the liveweights of the two breeds were similar by 80 days of age. There were no significant differences due either to breed of lamb or to breed of dam in lucerne meal intake by lambs and ewe milk yield. We conclude that the lamb's genetic potential for growth and maternal environment were of approximately equal importance in determining the superior growth of lambs born and reared by first-cross Merino dams compared with those born and raised by Merino dams.
The effects of nematodiasis on weaner sheep in Western Victoria
Authors: Thompson RL , Callinan APL
Published: November 2004

The development of nematodiasis and its subsequent effect upon production from Merino weaner sheep in western Victoria was studied at Hamilton during 1975-77. In each year, all weaners were drenched in summer and allocated to groups of 36, stocked at 15 sheep ha-1. The groups were given oral anthelmintics weekly, monthly or on five, two or one occasions between March and December of each year. A further two groups were not drenched, but one of these groups was given access to anthelmintic blocks. Nematodiasis was prevalent from the commencement of continuous pasture growth in autumn until early summer. Its effect varied considerably between both years and treatments. Undrenched sheep gained 39-66% less liveweight and grew 16-30% less wool than sheep drenched weekly. In two of the three years, liveweight gain and greasy fleece weight increased with frequency of anthelmintic treatment. The mean faecal egg count (EPG) in untreated sheep during the three years was over 500 eggs g-1 dry faeces and the mean number of nematode larvae ha-1 (LPH) was c. 1 x l06. Only those groups of sheep receiving 5, 12 or weekly drenches during the experimental periods had EPG or LPH that were significantly less than those of the undrenched sheep. Two to five anthelmintic treatments between March and December gave adequate control of nematodiasis.
A comparative study of Hereford and Friesian steers. 2. Carcass characteristics and meat quality
Authors: Taylor DG
Published: November 2004

Two trials, each involving four Hereford and four Friesian steers, were finalized with the slaughtering of the animals and comparison of their carcass characteristics and meat quality. One trial involved hand-feeding the animals to achieve a constant liveweight gain of 0.68 kg/day from 6 months of age to slaughter at 15 months of age; the other trial used animals of the same age, but on ad libitum feeding. Carcass data substantiated the subjective observation that the Friesian carcasses were longer, less compact and displayed less desirable 'beef type' conformation than those of the Hereford. The dressing percentage of the Friesians was significantly (P < 0.01) lower than that of the Herefords. The Hereford carcasses had a significantly greater fat content than the Friesians, but lower percentages of both muscle and bone. The Hereford produced the greater yield of boneless retail meat (not fat trimmed), which could be attributed to their greater carcass fat and lower carcass bone content. The meat from both breeds was of equivalent palatability when assessed subjectively for tenderness, juiciness and flavour, and objectively for tenderness.
Arginine requirements of pigs between 7 and 28 days of age
Authors: Leibholz J
Published: November 2004

Thirty-two male pigs, 7 days of age were offered dry pelleted milk diets containing 6.8-11.5 g Arginine/kg in two experiments each lasting 21 days. The results from these experiments indicated that in pigs fed on diets containing 192-279 g crude protein/kg, 6.8 g arginine/kg was sufficient for growth. The weight gain of pigs fed on all-milk protein diets was 245 g/day, while that of the pigs fed on an isonitrogenous diet containing 65 g glycine/kg was 190 g/day. It was estimated that only 55 % of the arginine in the weight gain of the pigs could be of dietary origin.
Biocrystallization of quartz and calcium phosphates in plants — a re-examination of the evidence
Authors: Harper RJ , Gilkes RJ , Robson AD
Published: November 2004

The evidence advanced by McManus et al. (Aust. J. Agric. Res., 1979, 30, 635-49) in support of their hypothesis that quartz, apatite and whitlockite crystallize in growing plants has been re-examined and tested by further experimentation. It seems probable that quartz in plants is an airborne contaminant and that apatite and whitlockite crystallize during ashing. There are therefore no grounds for believing that these compounds form by biocrystallization.
Studies on alfalfa mosaic virus and alfalfa aphids
Authors: Garran J , Gibbs A
Published: November 2004

Alfalfa mosaic virus (AMV), the only sap-transmissible virus detected in a limited survey of lucerne crops in New South Wales and the Australian Capital Territory, is more common and widespread now than 10 years ago. Twenty-four of 35 lucerne crops and test plots we sampled were infected; from 25 % to over 55 % of plants were infected in plots and crops at Ginninderra, A.C.T. Seven of 10 commercial lucerne seed lots (eight of them imported directly from the U.S.A.) contained seedborne AMV, which infected from 0.4 to 1.9% of seedlings. The three lucerne aphids, the bluegreen aphid (Acyrthosiphon kondoi), pea aphid (A. pisum) and the spotted alfalfa aphid (Therioaphis trifolii f. maculata), all transmitted AMV in the non-persistent manner. Feeding-preference tests indicate that spotted alfalfa aphids prefer to feed on AMV-infected Siriver lucerne than on healthy Siriver, but they do not discriminate between healthy and AMV-infected Hunter River lucerne. The implications of these results are discussed.
Purification of a Tasmanian isolate of subterranean clover red leaf virus, and its serological interactions with a New Zealand isolate and other luteoviruses
Authors: Johnstone GR , Duffus JE , Munro D , Ashby JW
Published: November 2004

A Tasmanian isolate of subterranean clover red leaf virus (SCRLV) was purified and concentrated from pea (Pisum sativunz L. cv. Puget) by tissue extraction with cellulase followed by heat clarification, precipitation with polyethylene glycol in salt, and differential and density gradient centrifugation. Virus particles were isometric and 27 nm in diameter. Aulacorthum solani (Kalt.) acquired virus particles from the preparations through Parafilm membranes and transmitted them to healthy subterreanean clover test seedlings, causing disease symptoms of SCRLV. Isolates of SCRLV from Tasmania appeared identical with those from New Zealand on the basis of particle morphology and serological tests. Tasmanian SCRLV was distantly related serologically to Californian isolates of beet western yellows (BWYV) and legume yellows (LYV) viruses. Tests indicated that the relationship was closest with a potato isolate of BWYV and most distant with LYV. Virus particles in sap extracts from infected pea plants were readily detected by electron microscopy following adsorption onto grids coated with SCRLV antiserum, but not on grids coated with antisera to BWYV and LYV. These data confirm that SCRLV is a new, distinct member of the luteovirus group.
Effects of environmental variables on the competition between inoculum strains and naturalized populations of Rhizobium trifolii for nodulation of Trifolium subterraneum L. and on rhizobia persistence in the soil
Authors: Brockwell J , Gault RR , Zorin M , Roberts MJ
Published: November 2004

Experiments were conducted at six field sites in south-eastern Australia with three cultivars of Trifolium subterraneum L, inoculated with diverse strains of Rhizobium trifolii. The various locations provided different edaphic and climatic conditions for plant growth, and naturalized populations of R. trifolii provided competition in forming nodules for the inoculum strains. Success of the inocula in forming nodules in the first year was used as an index of competitiveness, and success in the second year as an index of persistence. Inoculum strains formed a majority of nodules in the first year but fewer in the second. Inocula generally persisted better at those sites which had smaller populations of naturalized rhizobia. Competitiveness and persistence did not appear to be related characteristics, although some strains were superior to others especially in terms of persistence. Values for strain persistence tended to be similar at locations where the Mt Barker cultivar was grown, indicating an effect of host on the expression of this character. Significant effects of soil texture, soil pH, or growth temperature (individually) on the relative competitiveness and persistence of the inoculum strains could not be measured, although the cumulative effects of these (and other) environmental variables may have been substantial. The inoculum strains could be assembled into groups according to strong relationships of nodulating performance at each harvest. Within these distinct groups, the nodulation behaviour of the strains relative to each other remained approximately constant, irrespective of the absolute levels of competitiveness or persistence, the location of the experiment, or the year of the harvest.
Uptake and distribution of chloride, sodium and potassium ions in salt-treated citrus plants
Authors: Grieve AM , Walker RR
Published: November 2004

Seedlings of a range of citrus rootstocks were grown under glasshouse conditions and supplied with dilute nutrient solution containing either 0 or 50 mM NaCl. The partitioning of accumulated chloride and sodium into and within the major organs was compared between plants of Rangpur lime (Citrus reticulata var. austera hybrid?), Trifoliata (Poncirus trifoliata) and sweet orange (C. sinensis). Rootstocks differed in their leaf and stem chloride and sodium concentrations, but there was little or no difference between the rootstocks in root chloride and sodium concentrations. The lowest leaf chloride and sodium concentrations were found in the top region of shoots of all rootstocks. The different patterns of accumulation of chloride and sodium found in the three rootstocks were consistent with the existence of apparently separate mechanisms which operate to limit the transport of these two ions from the roots into the young leaves of citrus plants. The chloride excluding ability of 10 rootstocks and two hybrids was also compared and assessed in relation to rootstock vigour. Sampling from the middle leaves on salt-treated plants enabled a distinction to be made between rootstocks in their chloride accumulation properties. Cleopatra mandarin (C. reticulata), Rangpur lime, Macrophylla (C. macrophylla) and Appleby smooth Seville (C. paradisi x C. sinensis) accumulated significantly less chloride than did Trifoliata and rough lemon (C. jambhiri). Differences in chloride accumulation properties between rootstocks were unrelated to rootstock vigour.
Water balance of three irrigated crops on fine-textured soils of the Riverine Plain
Authors: Mason WK , Meyer WS , Smith RCG , Barrs HD
Published: November 2004

Three summer crop species, maize, sorghum and sunflower were grown on three different fine-textured soils of the Riverine Plain in south-eastern Australia. At each site, above-ground growth, phenological development, and root length density were measured in two well-watered plots. Water use, plant water status and final crop yield were measured in the well-watered plots and in one plot per site where irrigation was discontinued around the time that complete crop canopies had developed. Plant available water was estimated from these drying-cycle plots. Crop water use calculated from soil water contents did not agree with estimates from a water balance model at two of the sites, suggesting that capillary rise from shallow water tables was supplying considerable quantities of water to the crops. Using the water balance model to predict actual evapotranspiration (Et), we estimated that after complete canopy development, up to 40% of Et was supplied to well-watered crops from a water table at approximately 1.5 m. At the site without a water table, yields from the drying-cycle plots were severely reduced and the estimate of plant available water (PAW) was thought to be realistic. It was concluded that where capillary rise or lateral movement of water into the root zone was significant, the concept of plant available water (PAW) was unsatisfactory.
Effects of water stress on in vitro dry matter digestibility and chemical composition of herbage of tropical pasture species
Authors: Wilson JR
Published: November 2004

The effects of water stress of varying duration and intensity (Dry treatment) on the in vitro dry matter digestibility (DMD) of different plant fractions of three tropical grasses (green panic, buffel and spear grass) and a tropical legume (Siratro) grown in plots under semi-arid field conditions is reported. Other plots of these species were irrigated regularly for comparison (Wet treatment). Generally, the DMD of herbage from water-stressed grasses was either similar to or higher than that from plants of the Wet treatment. Where DMD of leaves was higher for the Dry treatment this was usually due to a slower decline in their DMD as they aged. Most comparisons of dead leaf tissue indicated a higher DMD for the Dry than the Wet treatment. The most recently expanded leaves usually did not differ in DMD between Wet and Dry treatment. Water stress slowed stem development in the grasses and, particularly in early spring when this effect was most evident, the DMD of stem was higher in the Dry than the Wet treatment. Water stress applied to buffel grass stems after they had elongated and started flowering did not affect their DMD compared with the Wet treatment. Cell wall and lignin content of herbage from the Dry treatment was similar to or lower than that from the Wet treatment. In contrast to the grasses, the stress-adapted small leaves of Siratro, which developed after some time under water stress conditions, were lower in DMD than the recently expanded Wet leaves; their lignin and cellulose contents were higher but hemicellulose markedly lower than those of Wet leaves.
Populations of free-living stages of Ostertagia ostertagi and O. circumcincta in a winter rainfall region
Authors: Young RR
Published: November 2004

Pats of cattle faeces containing eggs of the trichostrongylid Osferfagia ostertagi and deposits of sheep faecal pellets containing eggs of O. circumcincta were placed on dry and irrigated pasture plots at four times during the period October 1977 to February 1978. Faecal pellets lost moisture far more rapidly than did dung pats. The rate of moisture loss from both faecal deposits was greater on dry plots than on irrigated plots. Despite large differences between irrigated and dry plots in soil temperature and soil and pasture moisture status, the temperatures recorded in both dung pats and faecal pellets were similar on all plots at each time of deposition. A significantly greater proportion of O . circumcincta eggs was recovered as infective larvae in faeces, on herbage and in soil compared with that of O. osterfagi eggs. Irrigation did not result in either substantially more eggs developing to infective larvae in faeces or higher recoveries of larvae from herbage and soil. No significant differences were detected in temperature or moisture measurements or in parameters of free-living development and larval survival between plots with long or short pasture herbage. There were marked differences between the population dynamics of the infective larvae of Ostertagia spp. and between the numbers of larvae on irrigated and dry plots. On dry plots, O . circumcincta migrated in abundance from faecal deposits after smaller falls of rain than were required for migration of O . ostertagi larvae. Larvae of both species persisted in abundance on the herbage of most dry plots until late spring. On irrigated plots, migration of both species of larvae occurred immediately and was independent of rainfall, but survival rate of larvae was lower than on the corresponding dry plots.
Differences between two grain sorghum genotypes in adaptation to drought stress. II. Root water uptake and water use
Authors: Wright GC , Smith RCG
Published: November 2004

A study of two sorghum hybrids, E-57 and TX-671, indicated that differences in grain yield under conditions of low rainfall were associated with increased extraction of soil water at depth. E-57 used less water before anthesis than did TX-671, which was more than compensated for by increased water use after anthesis. As soil water declined in a drying cycle, TX-671 tended to restrict its water use at a higher water content than E-57. The implication of these results is discussed.
Responses of grain sorghum to varying irrigation frequency in the Ord irrigation area. I. Growth, development and yield
Authors: Done AA , Myers RJK , Foale MA
Published: November 2004

The effects of five frequencies of furrow irrigation, ranging from every 7 days to once-only-at-sowing, on the growth and yield of six cultivars of grain sorghum were investigated at the Kimberley Research Station during the 1976 dry (winter) season. No rain fell during the experiment. The reduced water supply, both at 42-day intervals and at one irrigation (at sowing), depressed dry matter production and tillering at 42 and 77 days after sowing. The grain yield component most affected was number of grains per head, due entirely to a reduced number of normal florets. All stages of development were hastened by longer irrigation interval, except in the cultivar Q7844, where floral initiation was markedly delayed in all treatments relative to the 14-day irrigation interval. The optimum irrigation interval for grain yield was determined to be in the range of 12-18 days, although there were no significant differences among the three shortest irrigation intervals of 7, 14 and 28 days. The highest grain yield, 5810 kg ha-1, was achieved with the 14-day interval, whilst the lowest, 1980 kg ha-1, was from a single irrigation at sowing. Plant nitrogen yields were reduced at both the longest and shortest intervals.
A preliminary testing of plant analysis procedures for the assessment of the sulfur status of oilseed rape
Authors: Spencer K , Freney JR , Jones MB
Published: November 2004

The effects of sulfur and nitrogen supply on the distribution of sulfur in oilseed rape (Brassica napus cv. Oro) grown in a sulfur-deficient soil in a glasshouse were examined to provide basic information for the development of a diagnostic test for sulfur status. Even though the traditional diagnostic indices (total sulfur and sulfate concentration) were directly related to sulfur supply and exhibited wide ranges in values between deficient and non-deficient tissue, they suffered a number of drawbacks in the case of oilseed rape. The shape of the yield/composition relationship precludes the use of either total nitrogen to total sulfur ratio or the proportion of the total sulfur present as sulfate in very young plants as indices for predicting the adequacy of sulfur supply up to first seed set. However, either index looked promising at 59 days from sowing, especially if specific plant parts were selected for analysis. For diagnosis of the current sulfur status the proportion of the total sulfur present as sulfate gave a good indication at each sampling date, and the critical value for the shoots was relatively stable with respect to age and nitrogen supply. Total nitrogen to total sulfur ratio was satisfactory as a diagnostic index for the 59-day-old plants only. Whilst the relationships established between the indices on one hand, and plant part, age and nitrogen supply on the other, should also apply in the field environment, the magnitude of the critical ratios requires confirmation for practical application.
Effect of temperature on seed development in jojoba (Simmondsia chinensis (Link) Schneider). II. Wax content and composition
Authors: Dunstone RL , Tonnet ML , Wardlaw IF , Shani A
Published: November 2004

Jojoba plants were grown in large pots in temperature-controlled phytotron glasshouses. The flowers were hand-pollinated and the seeds were grown under a range of eight temperature regimens from 15/10 to 36/31�C (8/16 h; photoperiod 16 h). The concentration of wax in the seed was determined by nuclear magnetic resonance and the wax composition and the composition of the ethanolysis products of the wax were determined by gas chromatography. At 21/16�C the wax concentration increased with seed growth until the seed reached 75% of its mature weight and then stabilized at about 45%. The wax concentration in mature seeds was only slightly affected by temperature, except for the extreme treatments of 15/10 and 36/31�C where the concentration was reduced. The main effect of temperature on wax composition was the depression of the percentage of waxes with carbon chain lengths greater than 40 at temperatures over 30/25�C. This depression was associated with a reduction in the percentage of C22 and C24 fatty acids and alcohols. The effects of temperature will have to be taken into account by plant breeders selecting for high wax content or for a particular wax composition.
Deposition of copper, manganese, selenium and zinc in Merino sheep
Authors: Langlands JP , Bowles JE , Donald GE , Smith AJ
Published: November 2004

Ninety-six fine-wool Merino ewes, ranging in age from newly born to 74 months and in liveweight from 2.9 to 54.5 kg, were slaughtered and their livers and kidneys removed. The livers, kidneys and the remainder of the carcasses were minced separately and analysed for copper (Cu), manganese (Mn), selenium (Se) and zinc (Zn). Some of the ewes had previously been supplemented with Se or Cu. Regression relationships were calculated between the Cu, Mn, Se and Zn contents of the whole body and liveweight, or, in the case of Cu and Se, liveweight and the product of blood Se or liver Cu concentrations and liveweight. The relationships were used to derive mineral requirements for growth by using a factorial method, and the values obtained were compared with those reported in the literature. The quantities of Cu, Mn, Se and Zn stored in the liver and kidney, expressed as a proportion of whole body storage, were calculated and related to liveweight and other variables. Relationships for predicting liver and kidney weights from liveweight are also presented.
Water use efficiency of wheat in a Mediterranean-type environment. I. The relation between yield, water use and climate
Authors: French RJ , Schultz JE
Published: November 2004

The relations between wheat yield and water use were determined from field measurements in South Australia. Highest production of dry matter was 37 kg ha-1 per mm of water use and of grain was 12.7 kg ha-1 per mm. More than 70% of the total water use occurred by anthesis. Time of sowing and soil water content at sowing had a big influence on yield. The loss of water by direct evaporation was estimated to be 110 mm, equal to about one-third of the water use. The maximum efficiency of water transpired was 55 kg ha-1 mm-1 for dry matter and 20 kg ha-1 mm-1 for grain. The efficiencies of most of the crops were below this level. Yield (Y), water use (W) and evaporation (Ep) could be fitted to the de Wit formula Y = m W/Ep, but the m factor varied with the proportion of water use that was lost by direct evaporation.
Effects of drought, aging and phosphorus status on leaf acid phosphatase activity in wheat
Authors: McLachlan KD
Published: November 2004

Wheat plants grown at two levels of phosphorus supply were subjected to drought or given adequate water. Acid phosphatase activities in the youngest fully expanded leaves, and inorganic and total phosphorus concentrations in the plant tops were determined at four stages of crop development. Phosphatase activity increased with plant age, with phosphorus deficiency and with drought. Inorganic phosphorus concentration decreased with plant age and phosphorus deficiency. Drought markedly decreased the inorganic phosphorus concentration in phosphorus sufficient plants but had little effect on the concentration in deficient plants. Total phosphorus concentration increased as the plants aged and was greatest where the plants were phosphorus sufficient and adequately watered. Drought markedly reduced the total phosphorus concentration in phosphorus sufficient plants, but had little effect on the total phosphorus concentration in deficient plants. Leaf acid phosphatase activity was related inversely to the inorganic phosphorus concentration in the plant tops. Changes in activity with aging, phosphorus supply and moisture stress were associated with changes in the inorganic phosphorus concentration. An argument is developed which indicates that a single 'critical value' separating sufficient from deficient plants, either for phosphatase activity, inorganic or total phosphorus concentration, is not practicable. Different values will be required for different stages of maturity. Complications introduced by drought and aging, through their effect on phosphorus concentration and enzyme activity, were overcome by developing phosphatase zymograms. Two bands were specifically associated with phosphorus deficient plants irrespective of plant age or moisture stress. The technique offers further opportunity for studies in phosphorus metabolism and shou!d provide a useful means of diagnosing phosphorus deficiency in field groRn plants.
Some luteovirus diseases in Tasmania caused by beet western yellows and subterranean clover red leaf viruses
Authors: Johnstone GR , Duffus JE
Published: November 2004

A range of crop plants, pasture legumes and weeds, mostly with yellows symptoms similar to those caused by luteoviruses, were collected from the field around Tasmania and checked for infection with beet western yellows virus (BWYV) and subterranean clover red leaf virus (SCRLV) using aphids and indicator plants. BWYV was recovered from 216 of 897 plants tested, representing 30 different species and including 16 not previously recorded as natural hosts. SCRLV was recovered from 163 of 637 plants, representing twelve species including four not previously recorded as natural hosts. BWYV was isolated most often from composites and crucifers, while SCRLV was recovered most frequently from legumes. Eight plants were found infected with both viruses together. In host range studies, Tasmanian isolates of BWYV caused symptoms in lettuce, subterranean clover and sugar beet like those seen on these plants in the field from which the virus was isolated, and were thus similar to isolates of BWYV from North America. The Tasmanian isolates of BWYV were also closely related serologically to Californian isolates of BWYV; these were serologically quite distinct from isolates of SCRLV, and both these groups were serologically distinct from legume yellows virus and from potato leaf roll virus.
Furrow irrigation of grain sorghum in a tropical environment. I. Influence of period of inundation and nitrogen fertilizer on dry matter production, grain yield and soil aeration
Authors: Wright GC
Published: November 2004

An experiment was conducted during the dry season in monsoonal tropical Australia to determine the influence of applied nitrogen (N) and period of inundation during furrow irrigation on the growth and yield of grain sorghum. Water was run in the furrows for 3, 6, 12 and 24 h at all irrigations, which were applied every 7-10 days throughout the season. A sprinkler irrigated crop was used to represent zero inundation. Increasing the period of inundation from 0 to 24 h at each irrigation reduced grain yield by 43.8, 49.5 and 43.2% for crops supplied with 0, 80 and 170 kg N ha-1 respectively. This yield reduction was associated with fewer grains per plant, grain weight having only a small influence on final yield. Air-filled porosity of the soil recovered more slowly as the period of inundation increased. The time taken to reach an air-filled porosity of 0.10 at the 10-20 cm depth interval was highly correlated with grain yield. The results indicate that grain yield is strongly influenced by the duration of waterlogging associated with flood irrigation. To minimize yield losses crops should be irrigated and drained rapidly to reduce the duration and severity of soil anaerobiosis.
Effects of high temperatures on scald lesion development and sporulation in barley infected with Rhynchosporium secalis
Authors: Mayfield AH , Clare BG
Published: November 2004

Temperature treatment at 40�C, but not at 35�C, inhibited scald lesion production and sporulation of R. secalis in barley leaves infected by R. secalis if the temperature treatment was applied during the first 7-8 days of infection but not if infected plants were treated later than the eighth day. Exposures at 40�C for 4 h had a greater effect than exposures for 2 h in most cases, but increasing the treatment duration from 4 to 6 h did not reduce lesion development or sporulation further.
Responses of wheat to vernalization and photoperiod
Authors: Davidson JL , Christian KR , Jones DB , Bremner PM
Published: November 2004

The effects of vernalization and photoperiod on times from planting of seedlings to ear emergence were measured in 68 Australian and 49 overseas varieties of wheat, comprising a broad spectrum of genetic material, in a glasshouse in Canberra (latitude 35�S). Vernalization was carried out by growing germinated seedlings in the dark at 1-2�C for 6 weeks. Long photoperiods (16 h) separated unvernalized plants into two distinct groups, corresponding to commonly recognized spring and winter types. Responses to vernalization were generally small under natural photoperiods (11-15 h), but much more pronounced in long photoperiods, particularly with winter wheats. In a second experiment, 24 varieties of wheat gave widely different responses to vernalization treatments. With 8 weeks' vernalization and long photoperiods, all varieties reached ear emergence within 66 days, but in some winter wheats 4 weeks treatment had little effect and 6 weeks gave incomplete vernalization. Under the conditions of these experiments, Australian wheats showed a wide range of responses to photoperiod and a narrow range of responses to vernalization compared with overseas varieties. The need to investigate the control of flowering time in obtaining varieties suited to the high-rainfall zone of Australia is discussed.
Influence of salinity on ionic concentration and yield of three tropical grain legumes
Authors: Keating BA
Published: November 2004

The relationships between dry matter yield and ion concentration in three tropical grain legumes, viz. guar, cowpea and blackgram, were examined in soil salinized with a range of isosmotic levels of NaCl, CaCl2 and Na2SO4. The shoot yield of guar and cowpea was reduced to 50% of the control, at soil salt levels corresponding to electrical conductivities determined on saturated extracts (ECe,50%) of 11.8 and 11.6 dS m-1 respectively, the response being independent of the form of salt used. Both these species maintained low Na+ in shoots but accumulated moderate levels of Cl- in the presence of Cl- salts. The shoot yield of blackgram was less affected by CaCl2 salinity than NaCl salinity (i.e. ECe,50% = 13.6 dS m-1 compared with 8.8 dS m-1 respectively), whilst the growth response to Na2SO, was intermediate (ECe,50% = 10.8 dS m-1. Blackgram was found to accumulate large quantities of both Na+ (up to 1500 8mol g-1) and Cl- (up to 8 g-1) in shoot tissues. The use of isosmotic levels of different salts enabled the effects on growth of variation in ion concentration of shoots to be assessed, at the same potential level of water deficit. There was no evidence that ion excess was limiting growth of guar or cowpea, since large differences in ion concentration were not related to differences in dry matter yield. There was evidence that high ion concentrations in the shoots of blackgram, in particular high Na+ , limited growth under salinity stress. It is suggested that some benefit may be gained by searching for blackgram cultivars that accumulate less Na+ in shoots.
Yield potential of reduced-branching lupins (Lupinus angustifolius) on sandy soils in a short season environment
Authors: Hamblin J , Delane R , Bishop A , Gladstones J
Published: November 2004

Experiments that compare the yield potential of reduced branching narrow-leafed lupins with that of the conventional branched types show that on sandy soils of low water-holding capacity in a short season environment, reduced-branching lupins have a higher yield potential than current cultivars. The yield potential of these new types appears to be maintained over a wide range of environmental yield levels. L. angustifolius was higher yielding than L. albus or L. cosentinii genotypes of similar maturity.
Environmental response of spring wheat in the south-western Australian cereal belt
Authors: Rickert KG , Sedgley RH , Stern WR
Published: November 2004

The performance of the spring wheat cultivar Gamenya, the leading cultivar in Western Australia since 1968, was studied to identify key aspects of its response to the environment under typically dry conditions on two contrasting soil types: a heavy clay loam and a light loamy sand overlying clay in the Merredin region.In the rain-fed treatments the total water use was similar on both soils and was of the order of 240 mm. On the heavy-textured soil at high nitrogen, the foliage canopy developed more rapidly than on the light soil, resulting in earlier soil water depletion and haying off. Water use efficiencies of about 10 kg grain ha-1 per mm of water were similar to those reported for winter rainfall areas in south-eastern Australia. This suggests a greater degree of buffering against spring drought than is indicated by the high ratio of pre-anthesis to post-anthesis water use (3-4.7:l) relative to values of 2-2.7:l in other parts of the Australian wheatbelt. Data on the partitioning of dry matter indicated that this buffering of the harsh spring conditions at Merredin may be due to a greater contribution of assimilates from pre-anthesis storage, to grain filling. In dry environments, further critical evaluation is needed of the role of stored assimilates in grain formation.Faster canopy closure on the heavy soil resulted from a higher density of shoots and possibly larger leaves. This led to the suggestion that on heavier, more fertile soils, an ideotype with restricted tillering, may be higher yielding. By the end of the season ear bearing shoot densities and total water use were the same on both soil types, thus masking earlier important differences.
Studies with the Australian Cashmere Goat. I. Growth and digestion in male and female goats given pelleted diets varying in protein content and energy level
Authors: Ash AJ , Norton BW
Published: November 2004

Some aspects of growth and digestion were studied in Australian cashmere goats in two experiments. In the first experiment, weaner goats (initial LW 13.4 kg) were given three ground and pelleted diets (11.3, 16.0, and 20.9% crude protein) at two levels of intake. Growth rates were highest in males fed the high protein (HP) diet ad libitum (149 g day-1) and lowest in females consuming the low protein (LP) diet at restricted intakes (30 g day-1). Increasing the protein content of the diet resulted in significantly greater liveweight gains, although the improved growth could be largely attributed to increased intake rather than to enhanced feed efficiency. Males grew faster, retained more nitrogen and used feed with greater efficiency than did females. A second experiment with fistulated goats (mean liveweight 16.4 kg) fed the LP and HP diets from experiment 1 showed that organic matter (OM) digestion was greater in goats fed the LP diet (67.9% v. 65.3%). In contrast, the proportion of OM digestion which occurred in the stomach was greater for goats fed the HP diet (76.7 v. 57.4%). For both diets all of the cellulose and hemicellulose digestion took place in the rumen; however, substantial amounts of starch escaped rumen digestion. Large losses of nitrogen across the rumen (4.9 g day-1) in goats given the Hp diet resulted in reduced flows (11.1 g day-1) of non-ammonia nitrogen (NAN) to the small intestine, compared with the LP diet (12.7 g day-1). Digestion of NAN in the intestines was greater in animals consuming the LP diet, possibly reflecting the greater intestinal contribution made by non-microbial NAN. For both diets the ratio of protein to energy available (11.0 and 10.2 g protein MJ-1 ME for LP and HP diets respectively) was estimated to be in excess of maximum tissue requirements for growth.
The relationship between the cobalt nutrition of ewes and the vitamin B12 status of ewes and their lambs
Authors: Quirk MF , Norton BW
Published: November 2004

An experiment was undertaken at Mt Cotton, south-east Queensland, to investigate the relationship between the cobalt nutrition of ewes and the occurrence of vitamin B12 deficiency in ewes and their lambs. Ewes received either no supplementary cobalt (C), 0.03 mg cobalt day-1 (LC), 0.06 mg cobalt day-1 (HC) or a cobalt bullet and grinder (CB). LC and HC ewes received their supplement as a weekly drench. Supplementation commenced prior to joining, and ewes subsequently grazed pangola grass pastures containing between 0.05 and 0.11 mg kg-1 cobalt.Cobalt supplementation of ewes increased their liveweight, reproductive and lactation performance. The milk production of ewes was influenced by the level of supplementation, with C, LC, HC and CB ewes producing 31.1, 41.5, 47.7 and 50.31. of milk respectively during the first 4 weeks of lactation. The lower productivity of C ewes was associated with concentrations of vitamin B12 in serum of less than 200 pg ml-1 and with the presence of detectable concentrations of methylmalonic acid (>80 8moles l-1) and formiminoglutamic acid (>30 8moles l-1) in their urine.The growth of lambs was influenced by the cobalt nutrition of their dams; the mean liveweight gain from birth to weaning (14 weeks of age) for lambs from C, LC, HC and CB ewes was 95, 158, 194 and 231 g day-1. Vitamin B12 deficiency was evident in lambs reared by C ewes from 4 weeks of age, but lambs from LC and HC ewes did not become deficient until 8 and 12 weeks of age respectively. Lambs from CB ewes remained free of signs of deficiency prior to weaning. Urinary formiminoglutamic acid concentration was a more reliable indicator of vitamin B12 status in young lambs than urinary methylmalonic acid concentration. The concentrations of vitamin B12 in the serum of lambs were low in all groups (< 150 pg ml-1) and were generally unaffected by the cobalt nutrition of their dams.A dietary cobalt intake of about 0.15 mg day-1 appeared to be necessary for optimal milk production from ewes. However, this level of dietary cobalt was inadequate for provision of sufficient quantities of maternal vitamin B12 to meet the requirements of lambs in the later stages of lactation.
Agronomic potential of native grass species on the Northern Tablelands of New South Wales. I. Growth and herbage production
Authors: Robinson GG , Archer KA
Published: November 2004

The herbage mass and relative growth rate of six perennial native grasses were compared with two introduced temperate perennial grasses (Phalaris aquatica L. cv. Sirosa, Festuca arundinacea Schreb. cv. Demeter and the temperate legume, white clover (Trifolium repens L. cv. Haifa). Of the native grasses three were year-long green species (Danthonia linkii Kunth, Microlaena stipoides (Labill) R.Br., Poa seiberana Spreng), and three were summer-growing frost susceptible species (Themeda australia (R.Br.) Stapf, Sporobolus elongatus R. Br., Bothriochloa macra (Steud) S.T. Blake). The summer perennial species, in particular Bothriochloa, were highly productive. However, in addition to inability to produce or retain green herbage during the winter, the summer-growing perennials produced a lower proportion of leaf material, a feature likely to render them less acceptable for grazing. Themeda was an exception, and produced a high proportion of leaf throughout the growing season and retained green material longer into the winter. Among the yearlong green species, both native and introduced, Poa proved a most productive species with significantly higher green leaf production than any other species, both in terms of herbage mass and relative growth rate. Although Danthonia produced as much herbage as phalaris on an annual basis, it has a higher stem component overall, and its relative growth rate was higher in the warmer months and lower during the winter months. Only Poa, white clover and phalaris produced signficant amounts of herbage during the winter months. These data suggest that native species have valuable agronomic features which could be exploited by selection and plant breeding programmes to advantage by the grazing industry.
The influence of rumen volatile fatty acids on blood metabolites and body composition of growing lambs
Authors: Abdul-Razzaq HA , Bickerstaffe R , Savage GP
Published: November 2004

Changes in the body composition, blood metabolites and rumen volatile fatty acids were measured in growing 12-week-old lambs fed whole-loose barley or ground barley pelleted with minerals for 10 weeks. Feeding whole-loose barley produced a propionic type of rumen fermentation and ground barley pelleted with minerals, an acetic acid type.The propionic type of fermentation was associated with a significant increase in the plasma concentrations of glucose and insulin, a reduction in the concentrations of plasma urea, and a reduction in almost all of the plasma amino acids, particularly alanine, methionine, valine, isoleucine and leucine. There was also a significant increase in the amount of body fat and dry matter, a higher level of protein per kg fat free empty body weight, and a more efficient utilization of dietary energy in the animals with a propionic acid type of fermentation.The elevation in the concentration of rumen propionic acid produced two important changes. It increased the supply of the main glucogenic precursor propionate, which probably reduces the body's requirement for alternative gluconeogenic precursors, and it stimulated directly and/or indirectly the pancreatic secretion of insulin. The latter is most likely responsible for the efficient peripheral utilization of glucose and other nutrients in lambs with a propionic acid type of rumen fermentation.Thus, a propionic type of fermentation is associated with an increase in the plasma levels of glucose and insulin, an increase in fat deposition and an increase in the efficiency of ME retention; all of these factors contribute to the improved performance of this group of lambs compared to those with an acetic acid type of fermentation.
Inoculum density of Cochliobolus sativus in soil and common root rot of wheat cultivars in Queensland
Authors: Tinline RD , Wildermuth GB , Spurr DT
Published: November 2004

Common root rot was assessed in wheat cultivars grown at field sites in Queensland having low, intermediate and high inoculum densities of Cochliobolus sativus. The densities at seeding time in the upper 10 cm of the profile, were 3, 77 and 132 viable propagules per g soil respectively. Both incidence and intensity of disease at tillering, flowering and firm dough stages of plant development appeared closely related to inoculum density. Additional inoculum applied with seed increased disease markedly at the low inoculum density site and slightly at the intermediate site, and had no effect at the high inoculum density site, indicating a threshold level for maximum disease in the test. Reduction in dry weight of plants at the low and high sites paralleled the disease levels at the tillering and flowering stages. The relative reactions of the cultivars were expressed consistently: Songlen and Timgalen invariably were more diseased than Kite and QT2338/9. The results suggest that cultivars may be evaluated for resistance in the field from tillering onward if disease levels are adequate. C. sativus was the dominant fungus isolated from the subcrown internodes of plants from non-inoculated subplots. Its frequency of isolation was much less from the low inoculum density site than the intermediate and high inoculum density sites, and lower from Kite and QT2338/9 than from Songlen and Timgalen. Fursariurn chlamydosporum was isolated from subcrown internodes with increasing frequency as the season progressed. However, it was considered to be a secondary invader of the plant material.
Factors limiting the intake of feed by sheep. 11. The effect of pregnancy and early lactation on the digestion of a medium-quality roughage
Authors: Weston RH
Published: November 2004

Various aspects of digestion were studied at a constant level of roughage feeding in ewes bearing single or twin foetuses during pregnancy, and in ewes suckling a single lamb during early lactation. In pregnancy, ewes with twins responded similarly to those with singles, except that they drank more water. The responses to pregnancy generally increased in magnitude as pregnancy progressed. Late pregnancy was associated with increases in (i) digesta flows through the stomach, (ii) marker clearance rates through the alimentary tract, (iii) absorption rate of volatile fatty acids, (iv) non-ammonia nitrogen flow into the intestines, and (v) faecal water output, and decreases in (i) reticulo-rumen liquor volume, (ii) reticulorumen pools of volatile fatty acids, ammonia, sodium and potassium, and (iii) organic matter digestion. Lactation was associated with increases in (i) digesta flows through the stomach, (ii) marker clearance rate from the reticula-rumen, (iii) non-ammonia nitrogen flow into the intestines, (iv) rumen digesta pH and (v) flow of sodium and potassium from the reticulo-rumen, and decreases in (i) reticula-rumen pools of volatile fatty acids, ammonia, sodium and potassium, (ii) organic matter digestion and (iii) blood urea concentration. It was concluded that (i) the digestion responses were large enough to influence the interpretation of various nutrition studies in pregnancy and lactation, and (ii) the relative contributions of physical and hormonal changes to the altered digestion transactions need elucidation.