bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemical studies on proteinaceous attractants for fruit flies, including the identification of volatile constituents
Authors: Morton TC , Bateman MA
Published: November 2004

The chemical characteristics of protein attractants for the Queensland fruit fly, Dacus tryoni, have been investigated. Highly effective commercial fruit fly attractants were found to contain a large proportion of high molecular weight material. Lists are provided of the amino acids present in free and bound form in these hydrolysates. The products found by gas liquid chromatography-mass spectrometry analysis of methylene chloride extracts and head-space volatiles were mainly the primary and secondary products of amino acid degradation, including a number of aldehydes and significant amounts of ethylene. None of these aldehydes nor any of a number of others that may have been present in smaller quantities was found to be active when tested individually for attractancy. Nor did ethylene show any evidence of attractancy under the conditions of these tests. Strecker reagents (such as isatin), which stimulate the formation of amino acid degradation products, caused a temporary and relatively small elevation in attractancy of the commercial hydrolysates. Three enzymatic hydrolysates of a relatively pure protein (bovine serum albumin) were prepared and studied; one, a tryptic digest, was exceptionally attractive to the fruit fly. Analysis of methylene chloride extracts and head-space of these 'model' preparations revealed a number of significant differences between them, but the most important difference in relation to attractancy was found to be the presence of ammonium salts in the trypsin hydrolysate. Subsequent experiments showed that high attractancies could be attained by combinations of amino acid mixtures and ammonium bicarbonate, even though neither had high attractancy (under the particular conditions of these experiments) when tested independently. This apparent synergism was probably due to the attractancy of the ammonia coupled with a feeding stimulus provided by the amino acids.
Studies with the intraruminal selenium pellet. 1. Some factors influencing the effectiveness of the pellet for selenium supplementation of sheep
Authors: Hunter RA , Peter DW , Hudson DR , Chandler BS
Published: November 2004

A number of experiments were conducted to determine whether surface coatings on pellets, season of treatment, or age of sheep affected the efficacy of intraruminal selenium pellets, as measured by selenium status of the recipient sheep. Also, comparisons were made between pellets and oral drenches of sodium selenate, and between three brands of commercially available pellets. Plasma selenium concentration reached a maximum within 2 weeks of administration of either pellets or oral drenches. Thereafter concentrations declined rapidly, but with all three brands of commercial pellet examined, sheep would have been protected from white muscle disease for at least one year. There were, however, differences between brands; one brand of pellet maintained the sheep at a higher selenium status than the other two. Surface coating, season of treatment, and age of sheep had only minor effects on pellet efficacy.
Studies with the intraruminal selenium pellet. 2. The effect of grain size of selenium on the functional life of pellets in sheep
Authors: Hudson DR , Hunter RA , Peter DW
Published: November 2004

Grain size of elemental selenium is a major factor controlling the long-term effectiveness of intraruminal selenium pellets. Microscope studies of polished sections of new and used selenium pellets showed that two commercially manufactured pellets contained selenium with average grain sizes about 4 and 40 �m respectively. Plasma selenium concentrations in sheep treated with pellets containing the coarse-grained selenium were maintained at higher levels over longer periods of time than those measured for sheep treated with pellets with fine-grained selenium. Pellets removed from sheep after 2, 4, 8, 16 and 28 days showed a progressive increase in the degree of alteration of selenium to a compound of average composition (g/100 g) iron, 33.7; selenium, 51.3 ; oxygen, 15.0. After 28 days only a small percentage of elemental selenium remained in pellets with fine-grained selenium, whereas about 50% remained in pellets with coarse-grained selenium. CSIRO prototype pellets, for which long-term effectiveness had been established, also contained coarse-grained selenium, and remnants of selenium were found in pellets that had been in sheep for periods up to 3 years. Selenium, administered in gelatin capsules or as sachets containing glass-selenium mixtures, was stable under the pH-Eh conditions of the rumen, but was rendered unstable in selenium pellets or iron-selenium mixtures by the presence of iron. It is probable that the most rapid release of selenium to the sheep occurs as a result of a chemical reaction involving the oxidation of iron and concomitant alteration of elemental selenium to iron selenide.
An analysis of the growth of mung beans at a range of plant densities in tropical Australia. I. Dry matter production
Authors: Muchow RC , Charles-Edwards DA
Published: November 2004

An experiment was conducted during the wet season in monsoonal tropical Australia to determine (a) whether plant density affected above-ground dry matter production of Vigna vadiata cv. Berken and, if so, what those effects could be attributed to, and (b) if there were differences between V. vadiata cvv. Berken and CES-ID-21 and V, mungo cv. Regur in their efficiencies of utilization of incident light energy for the production of dry matter. Differences in above-ground dry matter production of the Berken crops growing at three different plant densities could be attributed primarily to the different times taken by them to reach full light interception. In contrast, differences in above-ground dry matter production between species and cultivars were due to differences in both their efficiencies of light utilization and the amounts of light intercepted by them. Further measurements are required to determine whether the observed differences in light utilization efficiencies are attributable to differences in potential photosynthetic activities or to differences in partitioning of dry matter between root and shoot.
The effect of temperature on the field softening of hard seed of Stylosanthes humilis and S. hamata in a dry monsoonal climate
Authors: McKeon GM , Mott JJ
Published: November 2004

The changes in hard-seed content in pastures of Stylosanthes humilis and S. hamata cv. Verano were studied at Katherine, N.T. Both field studies and laboratory ovens with diurnal temperature changes showed that maximum soil surface temperatures greater than 50-55�C were required to produce substantial softening of hard seed. The rate of softening increased with higher maximum temperature. At Katherine, only the September-November period (late dry season) was likely to produce soil surface temperatures high enough for softening in naturally occurring seed populations. S. hamata did not soften to the same extent as S. humilis under both field and laboratory conditions. In established pastures only 35 % of S. hamata seed softened in one year, compared with 60-80% in S. humilis. Management practices may be required to improve seedling regeneration or establishment of new pastures in S. hamata.
Fire and survival of Stylosanthes spp. in the dry savanna woodlands of the Northern Territory
Authors: Mott JJ
Published: November 2004

A series of burns was carried out during the early and late, dry season and early wet season, in mixed native grass-legume plots containing Stylosanthes humilis, S. hamata, S, scabra and S. viscosa as the legume component. The least mortality was shown by S. scabra, but its survival was poor in any sward more than 3 years old. After burning the other species relied solely on seedling regeneration for subsequent season's growth. Fire killed a considerable quantity of seed, but its heat softened hard seed in the soil and good germination occurred with summer rains. However, the presence of a large proportion of soft seed through the winter months could lead to out-of-season germination and subsequent death of seedlings after unseasonal winter rains. Although the total dry matter yield of swards was reduced by all fires, burning could play an important part in increasing yields of S. hamata in swards overgrown by dense native grass, since it increases the amount of soft seed in the soil. If burning causes a high mortality of mature plants of the perennials S. scabra and S. viscosa, a reduction in stocking rate may be needed to ensure regeneration of a productive sward, as these species have slow seedling growth rates.
Evolution of subterranean clover in South Australia. II. Change in genetic composition of a mixed population after 19 years' grazing on a commercial farm
Authors: Cocks PS , Craig AD , Kenyon RV
Published: November 2004

Change in genetic composition of a mixed population of subterranean clover was studied at Kalangadoo in the south-east of South Australia. The seeds from an experiment in which 25 late-maturing strains were compared, were sampled in January 1977, 19 years after the plants were originally sown in 1958. Quadrats along three transects over the approximate position of the old plots were sampled and seed yields measured. The soil was analysed for several chemical and physical properties at the site of each quadrat. Thirty seeds from each sample were germinated in a glasshouse and the resulting seedlings planted out as spaced plants. These were identified on the basis of flowering time and morphological variables; in this way the seed pool of each strain at each quadrat site was determined. Seed pools were adjusted for variation in distance of original plots from the transects by estimating the real position of each plot relative to the transect and calculating the relationship between seed yield and estimated distance. Highest adjusted seed pools were produced by CPI 14454B (820 kg ha-1), CPI 12695 (626 kg ha-1), Eden Valley (502 kg ha-1), and CPI 14197A (476 kg ha-1). Cultivars Mt Barker and Tallarook were also common, but it was deduced from their distribution that they had been continuously introduced to the site from surrounding fields by livestock. All but six of the original strains were recovered in the sampling. Also present were many divergent strains, which yielded 228 kg ha-1 or 31 % of the average seed yield of 744 kg ha-1. Twenty-four of the original 25 strains and five others-Woogenellup, Yarloop, Trikkala, Clare and a divergent strain naturalized at Kalangadoo-were sown in small plots. Twenty-five agronomic variables were measured, including seasonal herbage yields, petiole lengths, leaf areas, isoflavone contents, phosphorus and sulfur uptakes, above- and below-ground seed yields, seed and seedling sizes and permeability of seed coats. The fourth component of a principal component analysis of the data was related to seed pool (P < 0.001), and it is suggested that the variables contributing to this component are important in predicting the success of a strain at Kalangadoo. The most successful tended to have high yields of buried seed, high yields of herbage and long petioles in winter, high formononetin content, early maturity and small seedlings. The results are discussed in terms of factors affecting success, generation of new genetic diversity, and field implications.
Mixed model estimation of age and month of calving adjustment factors for milk and butterfat yields of New South Wales dairy cattle
Authors: Everett RW , Taylor JF , Hammond K
Published: November 2004

Month-age adjustment factors for milk and butterfat yields were estimated from 504063 lactations on 239 518 cows located in 6 145 herds in New South Wales by mixed model methods, which eliminate biases due to genetic trends, environmental trends and culling. June, July and August are the most favourable months for calving, and December and January are the least favourable, resulting in 8 to 22% less production. Friesian cows are less affected by calendar month of calving than the other breeds. Results indicate the existence of large differences between breeds in rate of maturity. Ayrshire and Jersey cows attain mature yields at a younger age than AIS, Guernsey, Friesian and AMZ cows.
Reaction of soybean cultivars to races of Phytophthora megasperma f.sp. glycinea present in Queensland
Authors: Rose JL , Irwin JAG , Ryley MJ , Langdon PW , Jenner LB
Published: November 2004

Phytophthora megasperma f.sp, glycinea, the cause of phytophthora root and stem rot of soybeans, was found to be widespread in southern Queensland. Race determinations on 56 isolates were made at 26�C using the North American differential set. Thirty isolates resembled race 1 (virulent only on Harosoy), while the remaining isolates killed varying proportions of the other six differentials. Two of these isolates most closely resembled race 15. When race determinations were repeated for four isolates at 31�C, each isolate was more virulent on most of the differentials. One isolate resembling race 1 at 26�C would have been classified as race 2 at 31�C. All of the cultivars grown in Queensland were susceptible to hypocotyl inoculation, indicating the absence of genes conditioning resistance to races 1 and 15. Small proportions of plants in some cultivars, including Davis and Bragg were resistant to hypocotyl inoculation. The field resistances of 21 cultivars and breeding lines were assessed in a disease nursery. Progressive assessments of disease incidence were significantly correlated with grain yield and plant height. Davis had the highest level of field resistance while Ross and Semstar had the lowest. A breeding line (HS 1115) was identified as highly resistant to the fungus, both in the field and following hypocotyl inoculation. Three F6 lines from the cross Davis x Bragg showed a range of disease reactions, with the best showing an equivalent level of resistance to that of Davis.
Relationship between time of anthesis and grain yield of wheat genotypes with differing developmental pattern
Authors: Woodruff DR , Tonks J
Published: November 2004

This paper reports studies of the effects of time of planting and genotype on wheat grown with and without irrigation in Queensland. Under irrigation, and in the absence of frost damage, the grain yield of a number of semidwarf wheat genotypes was highest when anthesis occurred in midwinter. There was a linear decline in grain yield with departure from this anthesis period, associated with rising evaporative demand and daily mean temperature. Genotype variation in this yield pattern was due to different growth durations and in particular to the leaf areas developed by anthesis, which were often limiting yield especially in very early planting of quick genotypes. Under dryland conditions similar patterns of grain yield variation with anthesis date occurred, although the genotype variation about this pattern depended upon the interaction between growth duration and leaf area development on the one hand, and water use on the other. These results suggest that some consideration be given to altering the agronomy, in regions of low frost risk, to take advantage of the higher yield potential associated with midwinter anthesis dates. The effects of growth duration, anthesis date and environment could be integrated into a yield index of the form Grain yield index = a + b(T/E0) x (l/Tm), where a and b are constants, T, E0 and Tm are transpiration (mm), pan evaporation (mm) and mean daily temperature (�C) respectively, all estimated or measured within � 10 days of anthesis (r2 = 0.801, n = 112). The regression slope was constant across sites, times of planting and irrigation treatments for closely related semidwarf genotypes, but was significantly lower for a group of taller wheats tested. These groupings were associated with differences in grain number per mZ. The similarity between this yield index and the crop growth index of de Wit suggests that grain yield in wheat is closely linked to the growth potential over a short period around anthesis.
The influence of spatial arrangement on grain yield of wheat
Authors: Auld BA , Kemp DR , Medd RW
Published: November 2004

In four experiments, conducted over three contrasting seasons on the central western slopes of New South Wales, the grain yields of three wheat cultivars (Condor, Durati and Phoenix) sown in rhomboidal, square and rectangular patterns were compared with yields from traditionally sown (Poisson distribution along rows 180 mm apart) and broadcast arrangements. Square sowing resulted in significant (P < 0.05) yield increases (due to an increase in ear number) over rectangular arrangements in one experiment at three sowing densities 75,150 and 200 plants m-2. In two drier years there was no significant effect of arrangement at any density (40-400 plants m-2) in any one experiment. There was, however, a consistent significant (P < 0.05) trend over all experiments over 3 years, described by a response surface, of decreasing yield with increasing rectangularity as density was decreased. It is postulated that this was due to reduced ability of the plants to utilize available space. Traditional (sown in three seasons) and broadcast (sown in one season) arrangements produced yields which were not significantly (P > 0.05) different from the highest yielding treatments. It was concluded that there is no advantage in changing from the traditional sowing pattern to any precise geometric pattern. However, in precision sowing, rectangular patterns will result in lower yields than square patterns as density decreases from 200 plants m-2.
Environmental effects on seed development and hardseededness in Stylosanthes hamata cv. Verano. II. Moisture supply and illuminance
Authors: Argel PJ , Humphreys LR
Published: November 2004

The effects of variation in moisture supply and of level of illuminance during seed formation on the development of hardseededness and on the seed production of Stylosanthes hamata cv. Verano were studied in two glasshouse experiments. Verano plants were grown in pots containing 1.6 kg soil and were watered daily to field capacity until early flowering (43 days after seedling emergence). From day 43 to day 116, the plants were watered every 1, 2, 3 or 4 days. Leaf water potential immediately before rewatering varied from c. -20 to -28 bars in the 4-day treatment. Yields of seed pods were 5.8, 4.6, 3.8 and 3.8 g in the I-, 2-, 3- and 4-day treatments respectively. Severe water stress greatly reduced inflorescence density, had lesser negative effects on frequency of blooming, floret number, seed setting and proportion of florets forming a lower (beakless) articulation, and increased individual pod weight. Watering treatment had transitory and inconsistent effects on hardseededness. Seed production of Verano plants grown after flowering under shades with 30,40 or 59 % transmission or no shade was reduced by low level of illuminance, mainly because of effects on floret number per inflorescence; the proportion of florets forming a lower articulation and individual pod weight (but not seed setting) was also reduced by shading. The seed moisture content at different harvest occasions appeared to influence hardseededness, but shading had no consistent effect.
The effect of molybdenum and sulfur on the kinetics of copper metabolism in sheep
Authors: Weber KM , Boston RC , Leaver DD
Published: November 2004

Sheep were given 0, 5, 10, 15 or 25 mg/day molybdenum with or without 1.1 g/day sulfur orally for 1 week, and the nature of the interaction between these elements and copper was then investigated by injecting 64Cu intravenously, and analysing the disappearance of 64Cu from the blood by compartmental analysis. Molybdenum treatment decreased the rate of disappearance of 64Cu from the blood, and this decrease was enhanced by the concurrent administration of sulfur. Analysis of the disappearance curves in terms of a three-compartment catenary model showed that calculated total liver copper pool size (mean�s.d. (n = 4)) was decreased from 37.5�6.4 mg (no treatment) to 6.3 � 1.9 mg (50 mg/day molybdenum plus sulfur), whereas the liver copper pool size (determined by biopsy) remained unchanged. The reduction in calculated pool size was proportional to the molybdenum dose and was similar in magnitude to the reduction in actual copper pool size obtained following long-term (6 months) dosing with molybdenum and sulfur. These changes were most likely due to alterations in the kinetic parameters responsible for the initial phase of removal of 64Cu from the blood, i.e. K21 (the rate of transfer between blood copper (Q1)and liver copper (Q1 + Q2)), and bloodcopper. Consequently, therelationship between K21,various blood copper fractions and molybdenum dose rate was investigated using the results of this experiment and data obtained from the literature; it was found that a reduction in the amount of copper in the blood which exchanged freely with the 64Cu was the most likely explanation for the decrease in the rate of disappearance of 64Cu from the blood following molybdenum and sulfur treatment.
The effect of cattle tick (Boophilus microplus) on the growth of Bos indicus × B. taurus steers
Authors: Sutherst RW , Maywald GF , Kerr JD , Stegeman DA
Published: November 2004

The effect of the tick Boophilus microplus on the liveweight of Bos indicus x B. tauvus steers was investigated using three levels of infestation during summer 1980, autumn-winter 1980 and summer 1981. Mean losses in liveweight per engorged female tick during each of the three periods were 0.72,0.47 and 1.52 gper tick respectively. The 1980 estimates were significantly lower (P < 0.05) than that in summer 1981, and the losses were independent of tick density. The loss per tick was unaffected by a supplement of molasses and urea in the autumn-winter period. Compensatory growth of those steers whose earlier growth was retarded by poor nutrition or ticks was investigated by keeping all the steers tick-free during spring. The previous medium and high tick groups gained 5-6 kg per animal more than the low group. Non-supplemented animals recovered all of their 14 kg disadvantage compared with the supplemented group. Mean tick survival rates varied from 9% in summer 1980 to 25% in autumn and 2% in summer 1981. They were reduced at higher densities but were unaffected by the nutritional supplement. The large variation in losses in liveweight per tick on these animals on the same pastures at different times suggests that differences in published estimates are frequently due to animal variation rather than to nutrition, cattle breed or environment. Economic thresholds were calculated for a range of effects of ticks and of chemical control costs. With a mean loss of 0.6 g per tick and 1983 dipping costs of $A1.35, the economic threshold is 158 ticks engorging per day per animal, assuming a kill of 97 %.
The effects of nitrogen nutrition of plants on the development of acidity in Western Australian soils. I. Effects with subterranean clover grown under leaching conditions
Authors: Jarvis SC , Robson AD
Published: November 2004

Subterranean clover was grown, under leaching conditions, in pots on cultivated and virgin acidic sandy soils from two sites in Western Australia. Nitrogen (N) was supplied to the plants either as NH+4, NO-3 or through symbiotic fixation. There were marked changes in the acidity of the soil as the result of the differences in catiot/anion balance induced by the different forms of N supplied. Thus plants supplied with NH+4 depressed the pH by 0.9 pH units, and those dependent upon fixation by 0.5 pH units. There was little change in pH when NO-3 was supplied. Changes in soil pH were strongly related to cation/ anion balance, with increasing acidity resulting from the decreasing ash alkalinity of shoots of plants supplied with NH+4. There were marked differences both between the two soils from the same site, as well as between soils from the two different sites, in the relationships between pH and soluble aluminium and pH and exchange acidity. It is suggested that differences in the form, as well as differences in the total amount, of organic matter could play a major role in controlling the development of acidity in such soils of low, permanent cation exchange capacity.
An evaluation of 15N methods for estimating nitrogen fixation in a subterranean clover-perennial ryegrass sward
Authors: Bergersen FJ , Turner GL
Published: November 2004

Nitrogen (N2) fixation by nodulated subterranean clover, in swards with perennial ryegrass, was studied by using the natural abundance of 15N in sward components compared with a method using artificial enrichment of the soil with small amounts of K15NO3. Significant differences between the 15N concentrations in ryegrass and clover enabled yield-independent estimates of the proportion (P) of clover nitrogen fixed from atmospheric N2. Yield-dependent estimates of P were also made during intervals of growth in autumn and in spring. Values of P increased with time and during spring were close to l00%, when maximum fixation rates were approximately 4 kg N ha-1 day-1. Consistent differences in 15N concentration of shoots and roots had little effect on P. Early in the experiment, natural enrichment gave lower estimates of P than 15NO-3 -enriched treatments. Yield-independent and yield-dependent methods gave similar estimates of P. During winter, when no net growth or nitrogen accumulation was recorded, there appeared to be loss of 15N from the plants, possibly because of loss of highly labelled plant parts, balanced by slow growth of tissue containing a lower 15N concentration. During winter, calculation of P was therefore unreliable.
Effects of potassium and sodium concentrations on growth and cation accumulation in pasture species grown in sand culture
Authors: Mundy GN
Published: November 2004

The effects of potassium (K) and sodium (Na) on growth and cation accumulation in pasture species were examined in two sand-culture experiments. In the first experiment perennial ryegrass was subjected to a wide range of K and Na concentrations, whereas the second experiment examined the effects of potassium-sodium substitution in solution on nine pasture species. Large increases in yield were obtained by increasing K concentrations. However, near maximum yields were also observed at suboptimal K concentrations when Na was included in the nutrient solution. High yields occurred when the ryegrass tops contained at least 4.8% K (1200 m.e./kg) without Na, but only 1.4% K (360 m.e./kg) with Na. Although Na reduced K accumulation in ryegrass, the effect of K on Na accumulation was considerable. All species showed a high K selectivity against Na, with subterranean clover being the least selective. However, all species were capable of high levels of Na accumulation in the tops. It was found that Na uptake was dependent on K concentration and, to a lesser extent, on Na concentration. Calcium and magnesium uptake was reduced by K and Na, but the reduction by K was greater than that of Na at equivalent concentrations. The relevance of these findings is discussed.
The effects of anthelmintic treatment and season on the quantity and quality of wool grown by Merino sheep
Authors: Barton NJ , Brimblecombe CJ
Published: November 2004

Groups of 30 Merino weaner sheep were grazed in East Gippsland, Vic., and subjected to one of four anthelmintic programs during the 12-month period from December 1977. They were treated with thiabendazole either weekly (W), nine times (H), three times (L) or once (S). These programs resulted in marked differences in the degree of parasitism between the groups. Over the 12 months, parasites had no significant effect on yield, staple length or crimp frequency. However, compared with the wool from sheep treated weekly, greasy wool production was depressed by 13, 22 and 20% respectively in sheep given nine, three or one anthelmintic dose. Fibre diameter was also reduced. Dyebands were used to delineate wool grown during summer, autumn, winter and spring. Where parasite burdens were minimized (W group), wool growth, fibre diameter and rate of staple growth increased each season throughout the year. There was little increase in these characters in the other three groups until the spring, and wool growth and fibre diameter were significantly less than that of the W sheep in all but the initial summer season. Wool growth:fibre volume ratios indicated that sheep continued to initiate new fibres at least until the end of summer, when they were 9 months old. The subsequent depression in the wool growth of sheep dosed at less than weekly intervals provides further evidence of the deleterious effects parasites may have on the production of young sheep, even where anthelmintic is administered fairly frequently.
Toxicity of Echium plantagineum (Paterson's Curse). 2. Pyrrolizidine alkaloid poisoning in rats
Authors: Peterson JE , Jago MV
Published: November 2004

Food pellets containing Echium plantagineum were incorporated into the diet of adult and weanling rats to provide either a 20 or a 40% level of Echium. These diets were fed, either continuously or intermittently, for 14 to 280 days. A high mortality from acute or chronic pyrrolizidine alkaloid poisoning occurred in all groups given Echium. Young rats fed on 20-40% Echium for up to 28 days had a 70% mortality from acute haemorrhagic necrosis of the liver between days 22 and 35. Rats that received Echium continuously or intermittently over extended periods died with a mixture of acute necrosis and chronic liver damage typical of pyrrolizidine alkaloid poisoning. Young rats fed on 40% Echium for only the first 14 days, and having consumed no more than 0.7 g total alkaloid per kg liveweight, developed extensive chronic liver damage, leading to deaths from the 35th day after the start of feeding. The activity of liver microsomes in the production of pyrrolic metabolites from Echium alkaloids was 5-7 times greater in rats than in sheep. These results are discussed in relation to the relatively very low susceptibility of sheep to ingested Echium alkaloids.
Growth, mineral composition and digestibility of maize, sorghum and barnyard millets at different temperatures
Authors: Muldoon DK , Wheeler JL , Pearson CJ
Published: November 2004

Barnyard millets (Echinochloa utilis and E. frumentacea), maize (Zea mays) and a sorghum hybrid (Sorghum bicolor x S. sudanense) were grown as spaced plants at temperature regimens from 15/10 to 33/28�C (dayhight). Leaf and stem dry weight, leaf area and leaf number were recorded every 2 weeks and the dry matter analysed for nitrogen, sulfur, sodium and in vitro digestibility. Tolerance to low temperatures was in the order maize > E. utilis >sorghum >E. frumentacea. At mean temperatures above 25�C, relative growth rates were similar for all species. Differences in leaf area, for which individual leaf size was mainly responsible, accounted for most of the dry weight responses to temperature, although net assimilation rate responses were also apparent. The dry weight response to temperature became negligible after adjusting for differences in stage of development. Dry matter digestibility decreased with temperature; it also decreased with time because of deteriorating stems, except in sorghum. Maize leaves were of low digestibility, similar to stems. The nitrogen : sulfur ratio of all species remained steady with age; in sorghum at low temperature it exceeded the 15: 1 maximum considered desirable for animals. Sodium was highest in E. utilis stems and increased with temperature, in contrast to sorghum. Maize had a marginal nitrogen: sulfur ratio and unacceptably low sodium concentration. It was concluded that more attention should be given to E. utilis as a forage for cool climates.
Factors affecting diet selection by sheep. 2. Height and density of pasture
Authors: Black JL , Kenney PA
Published: November 2004

Boards of artificial pasture were prepared by threading the top two leaves of tillers from either ryegrass or kikuyu grass, in their vegetative stage of growth, through 5-mm-diameter holes in pressed hardwood sheets. The holes were spaced in rows from 10 to 50 mm apart, and, with one, two or three tillers per hole, tiller density ranged from 346 to 25 980/m2. Sward height was varied by pulling tillers different distances through the holes before they were fastened to the underside of the boards, and the mass of herbage dry matter ranged from 0.04 to 7.61 t/ha. In series I experiments, the effects of sward characteristics on ingestive behaviour of two sheep were examined, whereas, in series I1 experiments, pastures that were consumed at different rates were offered in pairs and the preference of one sheep observed. The rate of pasture intake was related to sward height only when tiller density was constant and to herbage mass per unit volume (bulk density) only at similar sward heights. Intake rate was better described by herbage mass per unit area but, at herbage availabilities of less than 1 t/ha, intake rate was several-fold greater when sheep grazed tall, sparse pastures than short, dense pastures. The best predictor of pasture intake rate was herbage mass per area effectively covered by one bite. Intake per prehending bite declined with a reduction in both sward height and density, and was also best described by herbage mass per area effectively covered by one bite. Prehending bite rate doubled as intake per bite declined from 200 to 10 mg dry matter. The rate of jaw movements during grazing was virtually unaffected by sward characteristics; prehending bites accounted for 20% of jaw movements when intake per bite was 200 mg dry matter and 80% of jaw movements with short, widely spaced swards. When two pastures with different sward characteristics were offered together, sheep generally preferred the one they could eat faster.
Effects of soil temperature and moisture on the pathogenicity of fungi associated with root rot of subterranean clover
Authors: Wong DH , Barbetti MJ , Sivasithamparam K
Published: November 2004

The effects of soil temperature (10, 15, 20 and 25�C) and moisture (45% water holding capacity (WHC), 65% WHC, and flooding) on the pathogenicity of five fungi, both alone and in combinations, were investigated to determine the involvement of these fungi in a severe root rot disorder of subterranean clover in Western Australia. Fusarium avenaceum, Pythium irregulare, and Rhizoctonia solani were highly pathogenic while Fusarium oxysporum and Phoma medicaginis, particularly when used singly, were only weakly pathogenic. Compared with individual fungi, fungal combinations increased the severity of root disease and decreased plant survival and plant fresh weight. While the fungi investigated caused root rot over the range of soil temperatures and moisture conditions of this investigation, the most severe root rot occurred at 10�C, with less at 15 and 25�C, and least at 20�C. Temperature had a marked effect on the disease severity and its effect varied with individual fungi and their combinations, in particular, combinations involving P. irregulare (severest root rot at 10 and 15�C). The most severe root rotting, compared with the control, occurred at 65% WHC, with less at 45% WHC, and least under flooding conditions. There was often a significant interaction between temperature and moisture for the various fungi and fungal combinations tested.
Genetic and environmental effects on a temperament score in beef cattle
Authors: Hearnshaw H , Morris CA
Published: November 2004

Temperament scores were taken on 8-month-old calves from five calf drops (1976-80) and over three sections of a large crossbreeding trial on the North Coast of New South Wales. A 0-5 scale was used, with lower values for quieter cattle. The heritability �s.e. of temperament score of Bos taurus calves (sired by Hereford, Simmental and Friesian bulls) was 0.03�0.28, and for B. indicus-sired calves (Brahman, Braford and Africander bulls) 0.46�0.37, and for all data combined 0.44�0.25. There was a significant difference (P < 0.01) between the mean score of Brahman-sired halfbred calves (1.96) and B. taurus-sired calves (1.05). The difference was halved to 0.45 points for quarterbred Brahman calves versus B. taurus calves, i.e. as expected for an additive trait. There were significant differences in temperament among calves sired by B. indicus bulls, but there were no significant differences amongst the B. taurus sire breeds. The repeatability (mean � s.e.) of operators' score of 701 weaner calves was 0.67�0.08. From temperament scores of 315 cows at weaning in 1981, an operator repeatability of 0.82�0.08 was obtained. Correlations of cow and calf score were not consistent, but averaged 0.18�0.04 from 547 records. The repeatability of scores taken at two separate times on 132 calves, was 0.43�0.09. The group given a medium level of nutrition had significantly higher temperament scores than those given high or low levels. Sex effects were not significant on scores at weaning. A log transformation of the data equalized the variance of scores of different breeds, but did not affect the conclusions.
Effects of post-transplant water deficits on leaf development and yield of winter planted tobacco in north Queensland
Authors: Ferguson KH , Fukai S , Wilson GL , Toleman MA
Published: November 2004

The effect of water deficit on floral initiation, leaf development and yield of commercial leaf of tobacco planted in the winter was studied in northern Queensland. The deficits were induced by different watering treatments at transplanting in combination with a range of times during which irrigation was withheld after transplanting. In addition, the effect of two periods of water deficits on flower and leaf development was investigated in a pot experiment under controlled environment conditions. Water deficits after transplanting delayed floral initiation and allowed more leaves to be produced. Moreover, the size of most leaves of commercial value was increased by water deficit; for example, withholding water for 28 days after transplanting increased the area and dry weight of commercial yield per plant by 33%. Results from the pot experiment demonstrated that the larger leaf area resulted from an extended period of linear growth and a greater rate of expansion after water deficits were relieved.
The critical concentration of manganese in field-grown wheat
Authors: Graham RD , Davies WJ , Ascher JS
Published: November 2004

The critical concentration of manganese (Mn) in wheat tissues for optimal growth was determined from field experiments. In the youngest emerged blade showing a ligule (YEB), the critical concentration was 11 � 1 8g g-1 (DW). The critical concentrations for older blades and whole tops were: next leaf below YEB, 13 � 1 8g g-1 DW; older leaves, 16 � 1 8g g-1 DW; whole tops, 12 � 1 8g g-1 DW. The older blades were less sensitive determinants of the growth response and are not recommended tissues for analysis. Diagnosis using whole tops was less sensitive than with YEB, but analysis of whole tops may give an integrated picture of Mn deficiency where availability varies rapidly with time. The critical concentration of 11 � 1 8g g-1 in the YEB for growth is also the critical level for the appearance in that leaf of normal chlorophyll a fluorescence transients. The Fo/Fv ratio, a parameter of the leaf fluorescence transients, correlated well with the Mn concentration in the leaf and may prove suitable for the diagnosis of Mn deficiency in field-grown wheat. The critical level of Mn was the same for two genotypes differing in their ability to tolerate Mn deficiency in the soil. Grain yield responses and other relevant data collected over three years are presented. Analysis of grain was shown to be an unreliable method of diagnosing an earlier Mn deficiency in the crop.
Nutritional value of chickpea (Cicer arietinum) and pigeonpea (Cajanus cajan) meals for growing pigs and rats. 2. Effect of autoclaving and alkali treatment
Authors: Visitpanich T , Batterham ES , Norton BW
Published: November 2004

Four experiments were conducted with rats to investigate the effects of autoclaving and alkali treatment on the growth-promoting ability of pigeonpea meal. In the fifth experiment, the effect of autoclaving pigeonpea meal was evaluated with pigs. With rats, there was a quadratic response (P < 0.05) in growth and feed conversion ratio to autoclaving pigeonpea seed for 15 min at 100-140�C, with maximum response occurring at c. 124�C. However, growth rate was still lower and feed conversion ratio higher than those of rats fed soybean meal (P < 0.05). Imbibing pigeonpea seed in alkali and subsequently drying it to original weight did not reduce tannin content but did reduce the trypsin-inhibitor activity from 10.3 to 5.1 units mg-1. Although both alkali treatment and autoclaving of the alkali-treated seed improved the growth and feed conversion ratios of rats, these treatments did not overcome the differences in protein quality between the pigeonpea and soybean meal diets. Autoclaving pigeonpea seed for 15 min at 110, 124 and 140�C reduced the trypsin-inhibitor activity of the meals from 11.2 to 0.7 units mg-'. Compared to pigs fed on unheated pigeonpea meal, pigs given autoclaved meal had higher (P < 0.05) growth rates and improved feed conversion ratios. These improved growth responses were similar to those produced by soybean meal.
Comparison of non-evaporative heat transfer in different cattle breeds
Authors: Finch VA
Published: November 2004

Tissue conductance and non-evaporative heat loss from the skin were determined from measurements of body temperature, evaporative water loss, metabolic rate and heat storage in six steers in each of three breeds, Brahman (B), Brahman x Hereford-Shorthorn (BX) and Shorthorn (S). A group of six steers, two from each breed, remained in a climate room set at 25�C overnight, and during the following day all were exposed for 1 h to sequential increases in air temperature (28, 32, 37, 41, 43, 45�C). Each steer was measured at 25�C and after a 30-min exposure to each temperature. Tissue conductance increased with air temperature (Ta), reaching maximum values at 41�C, the rate of increase (W m-2 'C-I per degree rise in Ta) being for B 3.95, for BX 2.33 and for S 2,09. Between 41 and 45�C, tissue conductance remained constant in B but declined in BX and S with a concurrent increase in heat storage. Mean tissue conductance (W m-2 �C-1) of B was 63.5; BX, 56.1; and S, 47.8, values that were significantly different (P < 0.01). Expressed in terms of metabolic weight, the breed means of tissue conductance (litres O2 h-1 W-0.75 �C-1) were also significantly different: B, 0.56; BX, 0.43; and S, 0.33 (P < 0.005), with the relative differences similar to those calculated per unit area. Breed differences in tissue conductance may be related to variations in ability to redirect blood from the core to the skin. Non-evaporative heat loss comprised 55-65% of the total heat loss from the skin in all breeds at Ta of 25�C. The remaining heat was lost through sweating. As Ta increased and approached skin temperature, non-evaporative heat loss decreased but in B and BX remained 25% of the total heat loss from the skin. S steers, in contrast, sustained little non-evaporative heat loss as Ta increased because sweating rates increased 50% more than that required to dissipate the heat at the skin. The increase in absolute humidity of the chamber was associated with the excessive sweating in this breed.
Root distribution in space and time in Trifolium subterraneum
Authors: Pearson CJ , Jacobs BC
Published: November 2004

Distribution of length and weight of roots of subterranean clover cultivars Northarn and Nungarin were measured in the field throughout a growing season. Plants were grown at seven populations from 2 to 1510 plants per m2 in coarse sand which had a bulk density of 1.4 g cm-3. Root growth was described by its vertical and horizontal distribution as functions of population and time after emergence. Differences in growth between cultivars were small. Root depth, which reached a maximum (plateau) at about 90 days, did not vary with plant population. Root density (length per volume of soil) increased faster at high population due to a higher density of' roots beneath the mainstream and an attenuation with distance away from the mainstem which did not appear to be affected by population. Root densities were 10 cm cm-3 in the uppermost core (0-10 cm depth) and 1.6 -3.5 cm cm-3 throughout the rooting zone (0-50 cm) at 119 days after emergence. Root death, estimated from dichlorotrianzinyl staining, was negligible. Leaf area per plant declined with population above 16 plants per m2; leaf area per unit root length (in cores beneath the mainstream) declined 90-fold with increase in population. Top weight and burr yield per plant at final harvest also declined with increasing population; burr yield per m2 also fell significantly at the highest population. It is concluded that the amount of root per unit area increases with population and that plants appear to adjust conservatively in some respects (to much lower leaf area per root length) while being unable to sustain dry matter partitioning (reducing burr/top yields) at the highest population studied.
Comparison of body weight modification in chickens induced with the sex-linked dwarfing gene (dw) and by restricting access to food during rearing
Authors: Polkinghorne RW
Published: November 2004

Related dwarf and normal female chickens were allowed restricted or free access to food from 8 to 18 weeks in order to compare the relative effects of genetic and nutritional manipulation of body weight on a number of egg production traits. Production records were collected from a total of 770 adult hens individually housed in a randomized block design. From 8 to 18 weeks dwarfs grew less efficiently than normals within both the restricted and fully fed groups. A relationship between body weight and age at first egg was shown, with dwarfs and restricted birds laying at later ages than their counterparts. Egg weight at 34 weeks was related to body weight, but dwarfs laid smaller eggs than their normal relatives even when compared at equivalent initial weights. A relationship was shown between body weight and egg weight when expressed as a proportion of body weight, which held for both genetic and nutritionally induced differences. Restricted feeding during rearing increased egg number to 66 weeks in normal birds but not in dwarfs, and dwarfs laid fewer eggs than normals. Age at first egg had a major influence on egg numbers.
Comparative performance of five genotypes of Indonesian large ruminants. 3. Growth and development of carcass tissues
Authors: Moran JB , Wood JT
Published: November 2004

The chemical constituents of carcasses from 105 serially slaughtered bulls comprising Madura, Ongole, Bali, Grati (Friesian cross) and swamp buffalo were determined from ground rib joints from all animals and ground carcass sides from 48 bulls. Other carcass quality attributes were also assessed on each carcass. The bulls had previously been fed diets containing 85 or 30% concentrate for up to 280 days. Huxley's allometric equation was used in its logarithmic form as the basis for covariance analyses of the data. Rates of fattening on the 85% concentrate.diet, in decreasing order, were buffalo and Bali, Madura and Ongole, then Grati. There was a genotype by diet interaction for carcass protein, ether extract and energy in that the Madura bulls produced fatter carcasses on the high-concentrate but the leanest carcasses on the high-roughage diets. Buffalo carcasses were low scoring with small rib eye areas and high levels of subcutaneous fat, whereas the highest-scoring carcasses were those from Madura and Bali bulls. Genotype differences in daily carcass protein retention are discussed in relation to rate of maturing and also dietary influences.