bluuebunny/crossref_metadata_2025 huggingface dataset:
Rape and sunflower seed meals as supplements for sheep fed on oat straw
Authors: Coombe JB
Published: November 2004

Rapeseed meal (RSM), sunflower meal (SFM) and formaldehyde-treated (F) forms of these were compared with urea- and formaldehyde-treated casein (FCAS) as N supplements for sheep fed pelleted diets containing c. 80% oat straw. Sufficient supplement was added to bring the N content of each diet to c. 1.7%, and starch was added to the urea and FCAS diets to make all supplements equal in metabolizable energy content. Based on an assumed fractional outflow rate from the rumen of 0.06 h-1, the ruminal degradability of dietary N varied from a mean of 0.42 for diets containing formaldehydetreated supplements to 0.74 for non-treated supplements. The diets were fed to Crossbred wethers weighing c. 40 kg in a production experiment lasting 12 weeks, and in a metabolism experiment. In the production experiment, penned sheep fed the urea diet ate 1300 g DM day-1, gained 30 g Day-1 and grew 4.5 g clean dry wool (CDW) day-1 . Each of the protein supplements increased DM intake (mean 1860g day-1 P < 0-0l), liveweight gain (mean 148 g day -I, P < 0-001) and wool growth (mean 10.5 g CDW day-1; P < 0.01). Intake and liveweight gain were higher, and wool growth rate lower, on the SFM than on the RSM diet, while formaldehyde treatment of both meals stimulated intake, gain and wool growth although these differences were not always significant. Efficiency of wool growth, expressed as g CDW per g N digested, was least for the urea and SFM diets (mean 0.30), higher for the FCAS, RSM and FSFM diets (mean 0.40) and highest for the FRSM diet (0.48, P < 0.05). Mean digestibilities of organic matter (OM) and cell wall constituents for all diets were 0.47 and 0.44 respectively, with few significant differences between diets. Apparent N digestibility varied from 0.41 to 0.61 for the FRSM and FCAS diets respectively, while estimated true N digestibility varied from 0.72 to 0.88 for the same two diets. Nitrogen balance for the protein-supplemented diets (mean 2.68 g day-1) was higher (P < 0.001) than for the urea diet (-3.77 g day-1). During 6 h post-feeding, the mean rumen pH (6.50) and volatile fatty acid levels (60.9 mM ) showed few differences between diets, whereas rumen ammonia concentrations were significantly reduced by formaldehyde treatment of the protein supplements. It was concluded that RSM and SFM were effective supplements for sheep offered straw, with little difference between them except for wool growth. Formaldehyde treatment to confer resistance to ruminal degradation reduced N digestibility, but increased the efficiency of utilization of digested N for wool growth.
Comparative performance of five genotypes of Indonesian large ruminants. 1. Effect of dietary quality on liveweight and feed utilization
Authors: Moran JB
Published: November 2004

Diets containing 85% (high concentrate) or 30% (high roughage) concentrate were individually fed for 280 or 224 days, respectively, to young Madura, Ongole, Bali, Grati (or Friesian crossbred) and swamp buffalo bulls. Each feeding trial was divided into early or late periods to study the effects of approaching maturity on growth and feed use. The digestibility of dietary nutrients, the balances of nitrogen, phosphorus and calcium, and the metabolizability of the gross energy of the high-roughage diet were measured. Growth rates in decreasing order were Grati, Ongole, buffalo, Bali and Madura. Genotype differences in growth were generally the result of variations in intake rather than in feed use. There were genotype x trial interactions in feed intake and liveweight gain during the latter part of each trial in that on the high-concentrate diet, the performance of Ongole and Madura bulls was poorer than that of the Grati and buffalo bulls whereas performances were similar on the high-roughage diet. Dietary metabolizable energy contents were estimated to be 11.8 and 9.5 MJ kg-1 dry matter for the two diets, respectively. Liveweights were higher and more divergent between genotypes at the end of the high-concentrate feeding period. As they were also higher than those reported for mature animals maintained under traditional village management, it was concluded that indigenous Indonesian large ruminants would respond to improved feeding and management. However, their feedlot performances would be unlikely to equal that of dairy crossbred cattle.
Dispersal and establishment of slender thistle, Carduus pycnocephalus L. as affected by ground cover
Authors: Harradine AR
Published: November 2004

After 3 years of spread from sown infestations, slender thistle density in spring was 0.12 and 4.67 plants m-2 for plots in which the ground cover was dominated by cocksfoot and annual grass species, respectively. On plots maintained free of plants other than slender thistle ('bare plots'), the corresponding density was 47.31 plants m-2. Slender thistle seed was dispersed at least 10 m from the parent plant in the first year of seeding and plants were evenly spread over the bare plots after 2 years. After 3 years, slender thistle ingress was still occurring on the other plots. The results indicate the importance of ground cover, either of living plants or of litter, in reducing seedling establishment and seed dispersal of slender thistle.
Choline requirement of the preruminant lamb during the first two or three weeks of life
Authors: Al-Ali SJ , Malouf NM , Walker DM
Published: November 2004

Preruminant male crossbred lambs, aged 1-2 days at the start of the experiment, were bottle-fed on milk replacers containing casein as the sole source of protein for an experimental period of 15-21 days. Choline-deficient diets were used in experiment 1 to determine the effect on the performance of the lambs of thc dictary protein concentration (10, 15 and 25% protein energy), and in experiment 2 of different sources of fat (butter oil, maize oil or lard), unsupplemented, or with supplements of choline chloride or L-cystine. Supplements of choline chloride decreased liver fat content and decreased urinary creatine excretion, irrespective of dietary protein concentration or source of dietary fat. Ira general, urinary ammonia excretion increased as the sulfur amino acid content of the diets increased, but there were interactions with the source of fat, so that although sulfur intake remained constant ammonia excretion was higher with diets containing lard than with those containing maize oil or butter oil. The effect of the supplements of 1,-cystine on liver fat content and urinary creatine excretion was not significantly different from that of the unsupplemented choline-deficient diets. In experiments 3 and 4 a choline-deficient diet with 25% protein energy and butter oil as the source of fat was supplemented with graded amounts of choline chloride. Energy intake was ad libitum, or restricted to 80% of ad libitum. When the lambs were fed ad libitum there was a significant decrease in liver fat content even with the smallest supplement of choline chloride (c. 9 mg MJ-1 gross energy), but no significant effect when energy intake was restricted. Since liveweight gains and nitrogen balances were unaffected by the presence or absence of the choline supplements it was concluded that in milk replacers containing 25% protein energy from casein, with butter oil as the source of fat, supplementation with choline chloride to provide 9 mg MJ-1 gross energy (233 mg kg-1 dry matter) would be sufficient to prevent the increased deposition of fat in the liver during the 6rst three weeks of life.
Use of products of straw decomposition by N2-fixing (C2H2-reducing) populations of bacteria in three soils from wheat-growing areas
Authors: Roper MM , Halsall DM
Published: November 2004

The potential for N2 fixation by free-living bacteria using straw as a source of energy was evaluated in three soils (one from Gunnedah and two from Cowra) representative of the wheat belt in New South Wales. All three soils had a history of straw incorporation. The abilities of the respective microbial populations to use a range of carbon sources, including potential products of decomposition of straw, was determined and compared with the size and composition of each population. Neutral to alkaline (pH 7.4) soil of high (51%) clay content from Gunnedah produced higher rates of nitrogenase activity with straw than more acid (pH 5.6) lower (17%) clay containing soil from Cowra (site B). Gunnedah soil also contained a larger population of N2-fixing bacteria which used a broader range of energy sources than soil from either Cowra site B or Cowra site W (pH 5.8, clay content 34%). There was little difference in the composition of the N2-fixing populations in each of the soils except that Azotobacter spp. were absent from the acid Cowra soils. It was concluded that the difference in behaviour of the respective N2-fixing populations was primarily due to the physical characteristics of the soil affecting the numbers and activities of diazotrophic microorganisms. In addition some soil environments failed to support specific organisms.
Trace element nutrition of grazing ruminants. 1. Degree of oxidation, diet, frequency of dosing and location in the gastro-intestinal tract as factors affecting the ability of oxidized copper wire to promote hepatic copper storage
Authors: Langlands JP , Bowles JE , Donald GE , Smith AJ
Published: November 2004

Factors affecting the ability of oxidized copper (Cu) wire to promote hepatic Cu storage in penned and grazing sheep were examined in two experiments. The incorporation of molybdenum (Mo) and sulfur (S) into the diet did not reduce hepatic Cu storage, but storage was negligible when elemental Cu was used as the supplement, and it is suggested that dose rates could be manipulated by varying the extent of oxidation of the particles. Oxidized particles were relatively ineffective when held in the rumen in a nylon bag, and some of the variability in the pattern of hepatic Cu storage after dosing is likely to be associated with the rate of clearance of the particles from the rumen; there was no evidence that particles were rendered ineffective by being held in the rumen for up to 6 weeks. Excessive hepatic Cu concentrations were observed in some sheep and were attributed to the quantity of supplement given, the high Cu content of the basal diets, and to the failure to scale the dose in proportion to liver weight or liveweight. Dosing at 6-monthly intervals reduced variability in hepatic Cu concentration through time, but the strategy may lead to unacceptable hepatic Cu concentrations unless dose rates or the extent of oxidation of the particles are appropriately reduced.
Trace element nutrition of grazing ruminants. 2. Hepatic copper storage in young and adult sheep and cattle given varying quantities of oxidized copper particles and other copper supplements
Authors: Langlands JP , Bowles JE , Donald GE , Smith AJ
Published: November 2004

Hepatic copper (Cu) storage was determined by biopsy after oxidized Cu wire was given to sucking lambs at 0-43 days of age, and to weaned Merino sheep and Hereford cattle varying in age. Cu-calcium edetate (Cu-EDTA) and soluble glass pellets were also evaluated as Cu supplements. A dose of 45 mg oxidized particles/kg liveweight was predicted to induce a mean maximum response of 84 and 179 mg Cu/kg DM in hepatic concentrations in weaned Merino sheep and Hereford cattle at 49 and 100 days from dosing respectively; these responses should not result in unacceptable hepatic concentrations in cattle, or in sheep of low Cu status, but the response is variable, and supplementation as a precautionary measure without prior indications of Cu insufficiency is not desirable. The particles were effective when given to lambs from birth, but did not increase hepatic Cu concentrations in lambs when ewes were dosed post partum. A dose of 1 g particles/lamb was as effective as a 2 g dose in increasing hepatic Cu concentration, and lambs given 2 g were lighter than those given 1 g; the dose increased hepatic Cu concentrations for at least 292 days. Cu-EDTA was given subcutaneously at the rate of 50 mg Cu for sheep and 150 mg Cu for cattle, and was as effective in increasing hepatic Cu concentration as 45 mg oxidized particle/kg liveweight; it did not produce the severe reactions frequently reported in the literature. The soluble glass pellet was less effective, but studies with a later prototype suggest that subsequent formulations may be more satisfactory.
Influence of level and timing of shading on seed production in Panicum maximum cv. Gratton
Authors: Oliveira PRPde , Humphreys LR
Published: November 2004

Artificial swards of P. maximum cv. Gatton were shaded to 25% (L25) or 54% (L54) of the sunlight received in a glasshouse for various periods related to the floral initiation, exsertion, anthesis and ripening stages of the first-formed inflorescences. Shading did not significantly reduce shoot yield. Seed yield was 93 g m-2 in the control treatment, relative to 32-48 g m-2 in the L54 series; in the L25 series, yields varied from 4 g m-2 in the continuously shaded treatment to 29 g m-2 in a late-shaded treatment. Reduction in seed yield was caused by a substantial decrease in the ratio of spikelets setting seed, and to a lesser extent by a decreased number of spikelets differentiated per inflorescence primary branch. A brief period of shading or early shading reduced seed setting in inflorescences emerging subsequent to the removal of shades. Shade slightly reduced 100-seed weight, and slightly increased branch number per inflorescence, and early shade delayed the time at which inflorescences reached anthesis. These findings require field confirmation. It is postulated that districts with high radiation receipt may have higher potential seed production and that crop management should be directed to promoting developmental phases in non-cloudy periods.
Effect of foliar applied manganese on the growth of safflower (Carthamus tinctorius L.) and the diagnosis of manganese deficiency by plant tissue and seed analysis
Authors: Lewis DC , McFarlane JD
Published: November 2004

The efficacy of foliar applied manganese (Mn) in preventing Mn deficiency in safflower (Carthamus tinctorius L. cv. Gila) was assessed in a black clay soil in the South-East of South Australia. The application of Mn significantly increased seed yield? from 1040 to 1450 kg/ha, through an increase in the number of seeds per plant. Maximum yields were attained by a foliar application of 500 g/ha of Mn. In the youngest open leaf the critical nutrient range (CNR) for Mn was 9-13 8g/g, while for the upper primary stem a CNR of 2-3 8g/g was determined. The CNR for Mn in the seed was found to be 5-6 8g/g.
An assessment of the depletion technique for comparative measurement of phosphorus uptake in plants
Authors: McLachlan KD , Kuang YH , Muller WJ
Published: November 2004

This paper examines the depletion of a standard 32P solution by 221 plants, either cereals or clovers, as a means of determining the recognized parameters, Vmax, Km and Cmin, in the kinetics of phosphorus uptake, and attempts to relate them to comparative phosphorus uptake by the plants, with a view to recognizing the more efficient ones.No single depletion curve was found. The data were grouped into six distinct curve types, based on the change in solution concentration (C) with time (t) and the rate of change in concentration (dC/dt) with concentration. The six types were part of one general curve which could be separated into 3 phases.In Phase 1, solution concentration was non-limiting, and plant performance was the principal determinant in depleting the solution. In the second and third phases, plant performance became progressively less dominant and the solution concentration more dominant in determining the concentration of the remaining solution.For comparative phosphorus uptake purposes, it is suggested that only the initial rate of uptake (Phase 1) is worth measuring and that this has attendant difficulties; the issue whether these kinetic parameters are real, or measurements of the model selected, is raised and discussed.No relation was found between these kinetic parameters and the efficiency of phosphorus use by subterranean clover plants grown in soil. Despite these practical shortcomings, variability in uptake capability between individual plants, even of the same line, was demonstrated. This plant variability offers a new area of plant nutrition for exploitation.
Cyclical fleece growth in cashmere goats
Authors: McDonald BJ , Hoey WA , Hopkins PS
Published: November 2004

Seasonal changes in fleece parameters were studied in mature feral doe goats, known to produce commercial quantities of cashmere and housed in natural light (NL) or continuous light (CL).Circannual changes in volume growth rate (VGR) of cashmere in NL were asynchronous with those of hair, resulting in maxima in April and November respectively, indicating that follicle-specific mechanisms are controlling the rate of follicle activities.Cycles of cumulative length of cashmere and hair in NL were synchronous. Cashmere maxima of 64.0 and 62.3 mm occurred in June and July respectively for two consecutive years. Distinct circannual cycles of linear growth (period, 365 days) were evident. While exposure to CL initially reduced the cycle period, after 2 years an extended cycle period emerged; this may have been due to photodesensitization.In NL, cashmere fibre diameter minima occurred at June-July and February each year. Hair fibres underwent only one cycle of diameter change each year. The period of the cycles was reduced by CL.An annual cycle of cashmere brush end fibre formation was apparent in NL. This cycle was associated with the cessation of growth in June-July, and a subsidiary event occurred between December and March. Continuous light accelerated brush end formation.Cyclic fibre shedding produced a circannual rhythm in fleece composition with maximum cashmere: hair ratio (CHR) in April-May in non-breeding goats. The maximum CHR of 5.9: 1 in NL did not reach its potential, as illustrated by the follicle S:P ratio of 6.9:1 in the skin. This suggests an irreversible loss of cashmere fibres from the fleece following the cycle of brush end formation in February.The maximum mean length of cashmere and time of occurrence were similar in grazing and penned does, although grazing does were only sampled in 4 months of one year.
Improvement of raw potato starch digestion in chickens by feeding oat hulls and other fibrous feedstuffs
Authors: Rogel AM , Balnave D , Bryden WL , Annison EF
Published: November 2004

Ground oat hulls significantly improved the digestion of raw potato starch for male broiler chickens. The improvement was dependent upon the level of oat hulls in the diet and the size of the oat hull particles. Rice hulls and barley hulls were as effective as oat hulls in improving raw potato starch digestion when fibre particles were larger than 1 mm in length. Wheat bran and hemicelluloses isolated from oat hulls had no effect on starch digestion. The improvement in raw potato starch digestion was accompanied by an accumulation of fibre in the gizzard and muscular hypertrophy of this organ. Broken raw potato starch granules were also observed in the gizzard contents.
A study of the characteristics of wool follicle and fibre in Merino sheep genetically different in wool production
Authors: Williams AJ , Winston RJ
Published: November 2004

Fourteen Merino ewes from each of two flocks, selectively bred for either high (Fleece Plus) or low (Fleece Minus) clean fleece weight per head, were randomly allotted to two feeding levels (17 v. 34 g kg-1 liveweight) of a good quality diet and offered these levels for 100 days. During the final 42 days, the rate of wool growth and its components were measured in each sheep. The Fleece Plus sheep had a greater density of wool follicles and produced more wool per unit area of skin. The latter trait interacted with the nutritional level; Fleece Plus sheep were more responsive to the higher nutritional level (45 v. 13%). Both the rate of growth of fibre length and the diameters of fibres produced in secondary follicles were the components associated with this interaction. The sulfur content of the wool was 12% less in wool from Fleece Plus ewes, but the difference between the two flocks was unrelated to the nutritional level. The average diameter (c. 83 8m) of the bulbs of the follicles did not differ between flocks or dietary levels, but follicles in the skin of Fleece Plus sheep were deeper (P < 0.05) below the skin surface (1.52 v. 1.38 mm). Despite the similar maximum bulb diameters, random longitudinal sections of follicles from Fleece Plus sheep had a 10% greater area of mitotically active tissue (P < 0.05). The difference was independent of nutritional level. When colchicine (10 8g) was injected intradermally, the number of cells revealing metaphase arrest within the mitotically active area of the follicle increased linearly with time to 6 h after the injection. The rate of increase in these cells expressed per unit volume of bulb tissue was not however influenced by either genotype or nutritional level. The average volume of cortical cells isolated from the fibres did not differ between genotypes or nutritional levels, but as with fibre volume, the volume of the cortical cells of the Fleece Plus sheep was more sensitive to a change in nutritional level (interaction: P < 0.05). Calculation of the rate of incorporation of cortical cells into fibre from both rate of production of fibre and the size of the cortical cells indicated that 20% more cells were incorporated by the Fleece Plus sheep and 17% more cells were incorporated by those sheep offered the greater dietary allowance. There was no significant interaction between genotypes and nutritional level for this trait.
The incidence of barley yellow dwarf viruses in wheat in Victoria
Authors: Sward RJ , Lister RM
Published: November 2004

Wheat crops from all major wheat-growing districts throughout Victoria were sampled during September 1984. Examination of pooled samples by enzyme-linked immunosorbent assay (ELISA) with an antiserum to a mixture of two barley yellow dwarf virus (BYDV) types ('V1') showed that 10 out of 26 crops were infected with BYDV and 3 out of 26 had a BYDV incidence greater than 10%. The overall loss in yield likely to result from BYDV was estimated at 2% with a far greater loss in some crops. Frozen-stored samples from four crops with high levels of BYDV were retested after one year with isolate-specific antisera. The results indicated that in these crops, PAV-related isolates were the most common, followed by RPV-related isolates.
Application of different sources of manganese sulfate decreases take-all (Gaeumannomyces graminis var. tritici) of wheat grown in a manganese deficient soi
Authors: Wilhelm NS , Graham RD , Rovira AD
Published: November 2004

Two experiments tested the effectiveness of manganese (Mn) decreasing take-all of wheat. The first experiment was conducted under controlled environmental conditions. Mn sulfate was mixed through the soil at sowing or 2 weeks before, or applied to the seed or leaves, and manganese dioxide (MnO2) was mixed through the soil at sowing or 2 weeks before. Mixing manganese sulfate (MnSO4) through the soil was the most effective treatment at decreasing take-all, followed by seed applied Mn. MnO2 and foliar applied Mn had little effect on take-all. All Mn treatments, except foliar Mn, completely eliminated Mn deficiency in the plants. In the second experiment, which was conducted in the field at a Mn deficient site, Mn sulfate and MnO2 were applied to the soil at sowing. MnSO4 decreased take-all and increased grain yields in take-all inoculated plots nearly threefold, but increased yields only slightly in uninoculated plots. MnO2 was not effective in decreasing take-all or increasing grain yield. This is the first report of take-all infection being suppressed by MnSO4in the field. The results of these experiments support the hypothesis that Mn may be acting through the physiology of the wheat plant to decrease take-all.
Estimation of leaf emergence rates of bananas
Authors: Allen RN , Dettmann EB , Johns GG , Turner DW
Published: November 2004

Leaf emergence rates (LER, leaves/day) of 17 AAA genome banana cultivars (Musa sp., subgroups Gros Michel, Cavendish, Red/Green-red) were estimated using a model based on mean monthly air temperature (13.3-27.9�C), daylength (10.2-13.8 h day), age of planting (48-1361 days), plant density (1111-2222 mats/ha) and cultivar stature (0.88-4.15 m). The LER model involved the five factors in a multiplicative form and was developed initially for one set of 612 observations on all 17 cultivars at Alstonville, N.S.W. but at one density only. The model indicated that LER increased with increasing temperature up to an optimum of c. 28.5�C. LER increased during plant establishment to a maximum at 64 days, then decreased to a stable value with increasing age. LER increased with increasing daylength, but decreased with increasing stature. The model predicted LER without bias for 16 of the cultivars, but slightly over-predicted LER in winter for the only representative of the Gros Michel subgroup (Highgate).Examination of independent data from South Africa revealed that LER decreased with increasing plant density. After the LER model had been adjusted for this effect, it gave an excellent prediction of LER for 229 observations in 20 additional data subsets from Alstonville, Innisfail (Queensland), Burgershall (South Africa) and Azaguie (Ivory Coast), with LERobs = (1.03 � 0.04) LERpred. - (0.005 � 0.004) and coefficient of determination of 0.71. After pooling all 841 observations into one data set, the coefficients of all five factors of the LER model were re-estimated. There were only minor revisions to the coefficients previously obtained, but LER was predicted with slightly greater precision than in the validation test above.
Protein intake and its relationship to urinary calcium excretion in the preruminant lamb
Authors: Walker DM , Al-Ali SJ
Published: November 2004

Preruminant male crossbred lambs, aged 1-2 days at the start of the experiment, were used. Twenty-four lambs were bottle-fed for an experimental period of 21 days in a 4 x 3 factorial experiment (with unequal replications). The sole source of protein in the milk replacers was casein, supplemented with DL-methionine, to supply either 10, 20, 30 or 40% of the total dietary energy as protein. At each protein level there were three levels of Ca to represent 50% (low), 100% (medium) and 200% (high) of the Ca concentration of ewes' milk (taken to be 360 mg MJ-1 gross energy). The Ca:P ratio in all diets was 1.1:l. The daily intake of gross energy was controlled at 1046 kJ kg-0.73. Nitrogen, Ca and P balances were determined during the last seven days of the experiment. There was no significant effect of protein intake, or of Ca intake, on the daily urinary Ca excretion, which was uniformly low (n = 24; mean, 1.67 � 0.25 mg kg-1).
Evaluation of chromosome substitution lines of wheat (Triticum aestivum L.) for freezing injury suffered during the stem elongation stage of development
Authors: Fletcher RJ , Cullis BR
Published: November 2004

Eight series of chromosome substitution lines in the Chinese Spring background were subjected to natural freezing stresses during stem elongation. Two of the series were also subjected to an artificial freezing stress at stem elongation. In the series involving the winter cultivar Cheyenne, a major genetic component of the resistance to freezing injury during stem elongation was located in chromosome 5D. Among the seven other series screened in the field, each of the 21 substituted chromosomes was significant in at least one series. Chromosomes most frequently implicated were 3A, 6A, 2D, 4D and 5D. The genetic control of observed tiller mortality following a freezing stress was therefore considered genetically complex.
Relationship between freezing injury suffered during the stem elongation stage of development and vernalization response in a winter wheat cultivar (Triticum aestivum L. cv. Cheyenne)
Authors: Fletcher RJ
Published: November 2004

The Chinese Spring (Cheyenne) chromosome substitution series was grown in three non-vernalizing environments and heading dates recorded. A vernalization treatment was superimposed on one environment. The major component of the vernalization response of the cultivar Cheyenne was located in the chromosome 5D line, presumably due to the presence of vrn3. Minor effects were located in other CS(Cnn) lines. Lines derived from the cross CS/CS(Cnn 5D) were grown in non-vernalizing environments and their Vrn3/vrn3 genotypes postulated. Differences between lines in resistance to freezing injury during stem elongation were not associated with variation of the Vrn3/vrn3 locus.
Use of surface films to reduce ammonia volatilization from flooded rice fields
Authors: Cai GX , Freney JR , Humphreys E , Denmead OT , Samson M , Simpson JR
Published: November 2004

This paper presents the results of experiments on the control of ammonia volatilization from flooded rice by the use of surface films of organic compounds.Preliminary experiments in evaporation pans, 1.2 m diameter, buried in an upland field of mown pasture, showed that ammonia volatilization from water could be reduced by applications of surface films of long chain alcohols; the effect increased with increasing length of carbon chain.The most effective way to add the film was to dissolve the long chain alcohol in ethanol, and to distribute the solution on the surface of the water.In an experiment in a flooded rice field, additions of cetyl alcohol dissolved in ethanol significantly reduced the rate of ammonia emission and total nitrogen loss. The effect was short-lived, probably due to microbiological decomposition of the cetyl alcohol and dispersion of the surface film by strong winds.
Ecology of the cattle tick (Boophilus microplus) in subtropical Australia. II. Resistance of different breeds of cattle
Authors: Sutherst RW , Maywald GF , Bourne AS , Sutherland ID , Stegeman DA
Published: November 2004

The resistance to the cattle tick, Boophilus mircoplus, of four herds of cattle with different Bos indicus (zebu) content, grazed at each of two locations in the subtropics of Queensland, Australia, was measured using artificial tick infestations at intervals of either 2 or 6 months over periods of up to 4 years. The factors affecting resistance of crossbred herds at each location in order of decreasing importance were the proportion of R. indicus genes, lactation, age interacting with nutritional conditions, a seasonal cycle which differed in timing at the two locations, and rainfall during the week of tick infestation. These variables accounted for 62% of the observed variation and the statistical model explained concurrent changes in resistance of other herds equally well. These findings are combined with data on the survival of freeliving stages of the ticks in a later paper to explain the observed variation in populations of cattle ticks on the untreated herds when grazing in separate pastures.
Phosphorus seed coatings for pasture species. I. Effect of source and rate of phosphorus on emergence and early growth of phalaris (Phalaris aquatica L.) and lucerne (Medicago sativa L.)
Authors: Scott JM , Blair GJ
Published: November 2004

Seed coatings containing phosphorus (P) can be an effective way of promoting early seedling growth in P-deficient soil, but there is insufficient information available on the P sources and rates which are both safe to germinating seeds and effective in supplying P. A growth chamber experiment was undertaken to study the effect on the emergence and early growth of phalaris (Phalaris aquatica L.) and lucerne (Medicago sativa L.) of seed coatings containing one of three P sources (mono-[MCP], di-[DCP], or tricalcium phosphate [TCP]) at three rates (0.625, 1.25 or 2.5 mg P seed-1). The emergence of lucerne was markedly delayed (as measured by fitted Mitscherlich functions) by increasing rates of MCP, whilst that of phalaris was only slightly delayed. DCP and TCP had only slight effects on the emergence of both species. Leaf number (at 27 days after sowing [d.a.s.]), dry matter yield and P content of shoots of both species (at 35 d.a.s.) were increased by all P sources. With phalaris, MCP was approximately four times as effective per unit of P as DCP, which in turn was approximately four times as effective as TCP, whereas, with lucerne, MCP was twice as effective as DCP, which in turn was twice as effective as TCP. The results show that whilst emergence was most affected by soluble P sources at high rates, these same sources were most effective in promoting early P uptake per unit of P applied.
Inheritance of resistance to potato virus Y in tomato
Authors: Thomas JE , McGrath DJ
Published: November 2004

A line of Lycopersicon hirsutum (P.I. 247087) was resistant to iystemic infection by 10 isolates of potato virus Y (PVY) from Queensland. The inheritance of resistance to PVY was studied in crosses between a susceptible tomato cultivar (L. esculentum cv. Floradade) and P.I. 247087. Analysis of segregation data from PVY-inoculated parent lines, F1, F2 and backcross generations, supported the hypothesis that resistance is conferred by a single recessive gene. However, the effect of this gene was, in some generations, apparently modified by the highly susceptible genetic background of Floradade tomato. A backcrossing programme has commenced to incorporate this resistance into a commercially acceptable tomato cultivar.
The nutritional value of rice pollard for sheep
Authors: Hogan JP , Cook LJ , Davis P
Published: November 2004

An investigation has been made of the nutritional value for lambs of diets containing rice pollard from which varying amounts of oil were extracted. The preparations were pelleted with equal amounts of wheaten hay to provide diets containing per kg, 12, 56, 80 and 107 g oil. A fifth diet was also prepared containing 106 g oil, and an additional 2.5 g calcium carbonate/kg. The diets were offered ad libitum to 46 crossbred lambs for 83 days, body weight changes being recorded over the final 53 days. Digestion in the stomach and intestines of similar lambs with fistulae in the rumen and abomasum was also measured with three diets. In the lamb growth experiment, no consistent effects of oil content or additional calcium were observed on feed intake, which ranged from 1.02 to 1.16 kg/day, on weight gain (1 11-148 &/day) or on feed conversion (7.9 - 9.2 kg feed per kg gain). Digestion studies with diets containing hay plus pollard alone, supplemented with calcium carbonate or with the pollard-oil extracted, indicated no differences in the digestibility of organic matter or aciddetergent fibre. However, appreciable grains of nitrogen in the rumen which occurred with the first two diets ensured that the quantities of crude protein apparently digested in the intestines were equivalent to 93-98% of protein intake. The corresponding value for the oil-extracted diet was only 66% of intake. Fibre digestibility, 250-320 g/kg intake, was not significantly different between diets. With the two nonextracted diets, a net loss of oil approximating 760 g/kg consumed occurred in the digestive tract, whereas with the extracted diet slightly more oil was excreted in the faeces than the amount consumed.
Salinity and drought stress effects on foliar ion concentration, water relations, and photosynthetic characteristics of orchard citrus
Authors: Syvertsen JP , Lloyd J , Kriedemann PE
Published: November 2004

Effects of salinity and drought stress on foliar ion concentration, water relations and net gas exchange were evaluated in mature Valencia orange trees (Citrus sinensis [L.] Osbeck) on Poncirus trifoliata L. Raf. (Tri) or sweet orange (C. sinensis, Swt) rootstocks at Dareton on the Murray River in New South Wales. Trees had been irrigated with river water which averaged 4 mol m-3 chloride (Cl-) or with river water plus NaCl to produce 10, 14 or 20 mol m-3 Cl- during the previous 3 years. Chloride concentrations in leaves of trees on Tri were significantly higher than those on Swt rootstock. Foliar sodium (Na+) and Cl- concentrations increased and potassium (K+) concentrations decreased as leaves aged, especially under irrigation with 20 mol m-3 Cl-. Leaf osmotic potential was reduced as leaves matured and also by high salinity so that reductions in leaf water potential were offset. Mature leaves had a lower stomatal conductances and higher water use efficiency than young leaves. After 2 months of withholding irrigation water, leaves of low salinity trees on Tri rootstock had higher rates of net gas exchange than those on Swt rootstock, indicating rootstock-affected drought tolerance. Previous treatment with 20 mol m-3 Cl- lowered leaf area index of all trees by more than 50%, and resulted in greater reserves of soil moisture under partially defoliated trees after the drought treatment. This was reflected in more rapid evening recovery of leaf water potential and less severe reductions in net gas exchange after drought treatment in high salinity trees on Swt rootstock. High salinity plus drought stress increased Na+ content of leaves on Swt, but not on Tri rootstocks. Drought stress had no additive effect, with high salinity on osmotic potential of mature leaves. Thus, the salinity-induced reduction in leaf area appeared to be independent of the Cl- exclusion capability of the rootstock and decreased the effects of subsequent drought stress on leaf water relations and net gas exchange.
The effect of weight stasis on the dissected carcass composition of crossbred sheep
Authors: Murray DM , Slezacek O
Published: November 2004

A study was made of the dissected carcass composition of crossbred wethers (progeny of Dorset Horn rams and Border Leicester x Merino ewes) maintained at 30 kg liveweight for either 0, 25, 50 or 75 days. Animals were individually penned and fed a pelleted ration of 80% lucerne chaff and 20% cereal grain (89.3% dry matter, I4.8To crude protein and 18.27 kJ/g gross energy). Cold carcass weight showed a significant increase (P < 0.05) in animals during weight stasis, although dry matter intake of animals during weight stasis decreased. All dissected carcass fat depots increased during weight srasis, although only subcutaneous fat showed a significant increase (P < 0.05) in weight. Neither the weight of total dissected side muscle nor total dissected side bone was affected by weight stasis. Only the weight of Standard muscle group 1 showed a significant response to weight stasis, and it increased (P < 0-05). Weight stasis had no effect on the weights of separate bones. Results for fat, muscle and bone distribution are reported. Subcutaneous fat formed a significantly increasing proportion of total side fat weight (P < 0.05) as duration of weight stasis increased, while intermuscular fat showed a trend to form a decreasing proportion. Weight stasis had no effect on the proportion of total side muscle formed by each of the Standard muscle groups, except group 4 which decreased (P < 0.05). Bone distribution was not influenced by weight stasis.
Studies on reproduction of Javanese thin-tail ewes
Authors: Sutama IK , Edey TN , Fletcher IC
Published: November 2004

Development of puberty (oestrus with ovulation) in two groups of 13 Javanese thin-tail (JTT) ewe lambs was studied from weaning at 13 weeks of age. The animals were fed ad lib. freshly chopped elephant grass plus either sufficient concentrate to grow at about 50 g per day (L) or ad lib. (H) concentrate from weaning to 5 weeks post-conception, and then studied through two pregnancies while on common feeding levels (Experiment 1). In Experiment 2, reproduction was studied in two groups of 13 JTT lambs which had been reared together and were given high or low nutrition from 5 weeks after their first conception until weaning of their second crop of lambs. The ewe lambs in Experiment 1 grew at 44 and 87 g per day (P < 0.01) for groups L and H respectively. Faster growth was associated with a younger age at first ovulation (190 v. 253 days), but differences in liveweight at first oestrus, first ovulation and puberty were marginal. Liveweight differences associated with differential feeding levels during rearing in Experiment 1 did not persist throughout the experimental period. Continuous high level feeding from early pregnancy (Experiment 2) resulted in a higher liveweight, and this was associated with higher ovulation rate (2.1 v. 1.6, P < 0.05) and an increase in the incidence of multiple births. However, this advantage in reproductive traits in the high feeding level group ewes was offset by higher wastage of ova (49 v. 20%) and higher pre-weaning lamb mortality (55 v. 33%). Average daily milk yield was non-significantly higher in the H group than in the L group in both lactations. In both experiments, improved feeding levels during rearing or thereafter reduced post-lambing re-breeding intervals. It was concluded that, while the JTT breed has unusually high, reproductive ability under low feeding regimes, most components of reproduction can be increased by strategic nutritional inputs.
Prenatal growth and estimation of fetal age in the Australian feral goat
Authors: McDonald BJ , O'Rourke PK , Connell JA , Hoey WA
Published: November 2004

The prenatal development of the conceptus in the Australian feral goat (Capra hircus) was studied in 47 does containing 89 fetuses of known gestational age. Quantification of the growth of the fetus allowed the development of a number of predictors of fetal age. The effect of age of fetus was highly significant for the variables body weight, crown-rump straight and curved length, vertebral column length, thorax circumference, forelimb length and hindlimb length (P < 0.01). A quadratic response curve using loge of fetal age accounts for most of the variation in the log, of each fetal measurement (R2 = 0.991 to 0.995). The prenatal growth of these fetal parameters was partitioned using the regressions. There was little difference between the relative growth of crown-rump straight and curved length, vertebral column length and the thorax circumference over the trimesters of gestation. Growth of the limbs tended to be greater in the third trimester when compared with the former parameters. As might be expected from work in other species, 79% of the growth in fetal body weight occurred in the last trimester, and this exceeded the relative growth of all other characters during this period. There was marked (P < 0.01) increase in the weight of the empty uterus up to day 95, after which no change occurred.
A model of individual variation in the food conversion efficiency and other growth parameters of grazing beef cattle in the tropics
Authors: Saithanoo S , Goddard ME
Published: November 2004

Methods to genetically improve gross food efficiency (GFE) in cattle usually rely on a high genetic correlation between GFE and growth rate. Estimating this genetic correlation for cattle grazing tropical pastures is extremely difficult, so a model of individual variation in growth has been developed based on component traits which are known to affect growth rate. The model assumes that there is individual variation in mature size, maintenance requirement, intake to maintenance ratio, and susceptibility to heat stress and to tick and worm infestation. Nutritional level is assumed to interact with maintenance requirement, so that under good nutrition a high level of maintenance requirement maximises growth rate, whereas under a low level of nutrition a low maintenance requirement leads to maximum growth rate. The model predicts that in the presence of environmental stress the correlation between growth rate and mature size is only about 0.5, and there is no correlation between mature size and GFE. Growth rate and GFE are correlated with resistance to parasite and heat stress and to intake:maintenance ratio. Consequently growth rate and GFE are highly correlated, especially under stressful environmental conditions. The model predicts that growth rate in one environment will be highly genetically correlated with growth rate in other similar environments.
The narrow-leafed lupin (Lupinus angustifolius L.) as a nitrogen-fixing rotation crop for cereal production. I. Indices of nitrogen fixation
Authors: Herridge DF
Published: November 2004

Experiments to develop indices of N2 fixation activity for the narrow-leafed lupin (Lupinus angustifolius L.) are reported. In Experiment 1 Unicrop narrow-leafed lupins were inoculated at sowing with effective Rhizobium lupini WU425. The conversion factor relating C2H2 reduction to N2 fixation was not constant throughout growth but increased from 0.9 (50-60 day period) to 6.6 (110-120 days). A nodulation index [(nodule wt/shoot wt) x 100], developed to account for plant size, declined with increasing nitrate supply and with increasing plant age. However, minor shifts in the nodulation index represented large shifts in plant dependence on N2 fixation (p), when plants were 60-100% dependent on N2 fixation. Concentrations of nitrate in extracts of the shoot axes and nodulated roots increased with increasing nitrate supply. Although the presence of nitrate in the rooting medium was evidenced by its presence in xylem exudate, the relationship between nitrate supply and the nitrate contents of xylem exudate was generally poor. Functions were developed to describe the relationships between the nodulation index and p, and between both shoot and root nitrate and p. Other experiments highlighted the synchrony of nitrate supply and its appearance in root tissues and the lack of diurnal fluctuations in nitrate concentrations of plant parts.
Identification, distribution and population variability of great brome (Bromus diandrus Roth) and rigid brome (Bromus rigidus Roth)
Authors: Kon KF , Blacklow WM
Published: November 2004

Seventeen populations of Bromus spp. were sampled from across southern Australia and accessions in the state herbaria of Western and South Australia were examined. Rigid brome (B. rigudus) differed from great brome (B. diandrus) in having shorter, sparser hairs on leaf laminae, more compact and erect panicles with shorter spikelet branches. In rigid brome, the abscission scars on the rachillae were elliptical and the lemma calluses were elongated (> 1 mm), while in great brome, these characters were circular and short (5 1 mm). Rigid brome was further differentiated into a long and short-awned biotype. Rigid brome was hexaploid, 2n = 42, and great brome an octoploid, 2n = 56. Rigid brome is widely distributed across southern Australia, often growing unrecognized in association with great brome. Rigid brome matured earlier than great brome, and there was high genetic variation (26-34% of total variation) in the time of maturity of both species. Seed production in rigid brome and great brome ranged from 1156 to 2908 and 661 to 3380 seeds per plant respectively. A short-awned ecotype of rigid brome from Geraldton, W.A., had 30% residual innate dormancy. This, together with the earlier maturity of ecotypes of rigid brome, may make it more difficult to control than a great brome when both species coexist in the field. Leaves of great brome were susceptible to rust (Puccinia bromoides Guyot), but associated ecotypes of rigid brome were rust free.