bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies of cattle and sheep eating leaf and stem fractions of grasses. 1. The voluntary intake, digestibility and retention time in the reticulo-rumen
Authors: Poppi DP , Minson DJ , Ternouth JH
Published: November 2004

Pangola grass (Digitaria decumbens) and Rhodes grass (Chloris gayana) were cut as 6 and 12 week regrowths, dried, chopped, and separated into leaf and stem fractions by using a gravity separator. Each of the eight diets was offered to four cattle and eight sheep fitted with a ruminal cannula to measure voluntary intake and digestibility of the dry matter (DM), organic matter (OM) and neutral detergent fibre (NDF). Possible deficiencies of protein and minerals were minimized in this study by feeding casein and a mineral supplement. The total DM, OM and NDF contents of the rumeno-reticulum (rumen) were measured by manually emptying the rumen and the values used to estimate retention times of DM, OM and NDF. Cattle consumed 35% more leaf than stem fraction. Sheep consumed 21 % more leaf. When the daily voluntary intake was expressed as g/kg0.9 the intake was similar for cattle and sheep. The higher intake of the leaf fraction was associated with the shorter time that it was retained in the rumen of both cattle and sheep. Leaf and stem fractions were digested to the same extent by cattle. There was also no difference in the digestibility of leaf and stem fed to sheep. The digestive efficiency of sheep was 0.033 lower than that of cattle for both DM and NDF. Cattle retained all diets for longer periods in the rumen than did sheep. This difference was associated with the higher digestive efficiency of the cattle. It was concluded that both cattle and sheep consumed more leaf than stem fractions of grasses, and that the higher intake of leaf was associated with the shorter time that it was retained in the rumen and not by differences in digestibility as such.
Studies of cattle and sheep eating leaf and stem fractions of grasses. 3. The retention time in the rumen of large feed particles
Authors: Poppi DP , Minson DJ , Ternouth JH
Published: November 2004

Pangola grass (Digitavia decumbens) and Rhodes grass (Chlovis gayana) cut as 6 and 12 week regrowths were separated into leaf and stem fractions and fed ad libitum to four cattle and eight sheep fitted with ruminal fistulae to determine the importance of particle size in controlling the retention time of feed in the rumeno-reticulum (rumen). Particle size was determined by using a wet sieving technique, and based on the cumulative dry matter distribution on the sieves of faeces from cattle and sheep; all particles >1.18 mm were described as large particles. The proportion of large particles was measured in the chopped diet offered, the masticated diet, the ruminal contents and the faeces. Chopped leaf and stem fractions contained 0.85 and 0.86 g/g large particles respectively. Mastication by cattle reduced the proportion of large particles in leaf and stem to 0.58 and 0.76 (P < 0.01), and mastication by sheep to 0.56 and 0.67 (P < 0.01). The proportion of large particles in the rumen of sheep was 0.236 and 0.249 for leaf and stem respectively (P > 0.05) and in cattle 0.272 and 0.345 (P < 0.05). The faeces contained relatively few large feed particles (< 0.045 for cattle and <0.018 for sheep). Cattle eating leaf and stem produced faeces containing 0.027 and 0.040 (g/g) large particles (P <0.05), compared with only 0,008 and 0.013 (P < 0.05) in sheep. Most of the large particles entering the rumen in the masticated feed disappeared in the rumen by breakdown to smaller particles or by digestion. In cattle the proportions that disappeared were 0.978 and 0.976 (P > 0.05) for leaf and stem, and in sheep 0.993 and 0.991 (P > 0.05). Large particles in leaf and stem were retained in the rumen of the sheep for 11.0 and 11.7 h (P > 0.05). Cattle retained large particles in all diets for a longer time (P < 0.01); 16.1 h for leaf and 20,2 h for stem (P > 0.05). Differences in retention time of large particles in the rumen did not appear to be the only factor controlling the retention of dry matter in the rumen and voluntary intake. A model was developed to describe the flow of large and small particles through the rumen. Intake simulation studies indicated that the most important factor influencing dry matter retention time in the rumen was the retention time of small particles (> 1.18 mm). Changes in the rate of breakdown of large particles had a small effect on dry matter retention time.
Growth and carcass characteristics of crossbred and straightbred Hereford steers. II. Carcass measurements and composition
Authors: Thompson JM , Barlow R
Published: November 2004

The effect of sire breed on the growth and development of carcass characteristics was examined in 104 steer carcasses, over the weight range of c. 300 to 600 kg liveweight. The carcasses were obtained from 28 straightbred Hereford, 27 Brahman x Hereford, 23 Simmental x Hereford and 26 Friesian x Hereford steers, which were grown on pasture and slaughtered in four groups when the Herefords weighed c. 270, 370, 470 and 570 kg liveweight. Changes in carcass characteristics with weight were examined by using the linear form of the allometric equation (log10Y = log10A+blog10X). As liveweight increased, the proportion of carcass in the body increased (b = 1.152). At the same liveweight, Brahman cross steers had heavier carcasses than the Hereford steers, which were heavier than either the Simmental or Friesian cross steers (P < 0.05). Fat thickness at the 12th-13th rib site, and kidney and channel fat weight both increased at a proportionally faster rate than carcass weight (b = 1.511 and 1 567 respectively). At the same carcass weight, Hereford and Brahman cross carcasses had a greater fat thickness than Simmental and Friesian cross carcasses (P i 0.05). Differences between sire breeds in kidney and channel fat weight were not significant (P > 0.05). C:rcass length and eye muscle area increased at a proportionally slower rate than carcass weight (b = 0.268 and 0.466 respectively). At the same carcass weight, Friesian cross carcasses were longer, and Simmental cross carcasses had a larger eye muscle area than the other breed crosses (P < 0.05). As total side weight increased, the proportions of subcutaneous and intermuscular fatAincreased (b = 1.554 and 1.535 respectively), and the proportions of muscle and bone decreased (b = 0.938 and 0.676 respectively). At the same side weight, the Hereford and Brahman cross carcasses had more subcutaneous fat than the Simmental and Friesian cross carcasses (P < 0.05). The Hereford carcasses had more intermuscular fat than the Simmental cross carcasses, which had more muscle than the other breed crosses (P < 0.05). Friesian cross carcasses had more bone than the Simmental crosses, with Brahman cross and Hereford carcasses having the least bone (P < 0.05). Brahman cross carcasses had a higher conformation score than the Simmental cross and Hereford carcasses, the Friesian cross carcasses having the lowest (P < 0.05). Samples of the M. longissimus from Brahman cross carcasses had a higher Warner-Bratzler shear force than samples from the other breed crosses (P < 0.05).
Sulfur and nitrogen fertilizer effects on wheat. II. Influence on grain quality
Authors: Moss HJ , Wrigley CW , MacRichie R , Randall PJ
Published: November 2004

A wide range of grain quality tests (on both a large and a small scale) was performed on samples obtained from a factorial (5 sulfur x 3 nitrogen treatments) field experiment in which Olympic wheat responded in yield of grain to both sulfur and nitrogen. Grain nitrogen concentration responded mainly to nitrogen supply and ranged from 1.38 to 2.56%. Grain sulfur concentration responded to both sulfur and nitrogen supply and varied from 0.08 to 0.18%. Flour sulfur was highly correlated with, but lower than, grain sulfur. Compared with high sulfur grain, low sulfur grain was harder (higher pearling resistance) and the dough had a greater resistance to extension and a lower extensibility. In fact, a restricted supply of sulfur seriously affected grain quality, producing a dough that was excessively tough and umuitable for normal use. These changes in dough quality were accompanied by decreases in the proportions of albumins and of high mobility gliadins in the total protein in the low sulfur grain.
Copper nutrition of subterranean clover (Trifolium subterraneum L. cv. Seaton Park). III. Effects of phosphorus supply on the relationship between copper concentrations in plant parts and yield
Authors: Reuter DJ , Robson AD , Loneragan JF , Tranthim-Fryer DJ
Published: November 2004

The effects of phosphorus supply on the relationship of copper supply with copper concentrations in various plant parts and yield of Seaton Park subterranean clover were examined. Plants were grown in a glasshouse for 40 and 74 days in pots with four levels of potassium phosphate (0, 13, 39, 65 mg phosphorus/pot) and six levels of copper sulfate (0, 50, 100, 200, 400, 800 pg copper/pot) added, in factorial combination, to a sand deficient in both phosphorus and copper. By increasing the phosphorus levels copper deficiency was induced partly by promoting growth and diluting copper concentrations in plants; and also by depressing copper absorption. Increasing phosphorus changed the distribution of copper in plant tops and the shape of curves relating copper concentration in whole plant tops to yield. At 39 mg phosphorus/pot, the relationship at Day 74 had a marked 'Piper-Steenbjerg' curvature, largely as a result of unusually high copper concentrations in the stems plus petioles of severely copper-deficient plants. At 65 mg phosphorus/pot, the relationship had no 'Piper-Steenbjerg' curvature for whole tops and only a relatively small curvature for stems plus petioles. The data suggests that 'Piper-Steenbjerg' curves in subterranean clover result primarily from high concentrations of copper in the stems plus petioles of severely deficient plants. At both harvests, young leaf blades had critical copper concentrations of around 3 �g copper/g at both 39 and 65 mg phosphorus/pot. However, copper-deficient plants with severe phosphorus deficiency did not respond to copper, and generally had copper concentrations below this critical level in all plant parts. The results confirm the value of copper analysis of young leaf blades for diagnosing copper deficiency in subterranean clover with moderately deficient to luxury supplies of phosphorus.
Genetic analysis in the pasture grass Setaria sphacelata. I. Dry matter yield and flowering
Authors: Hacker JB , Bray RA
Published: November 2004

The progeny of a 7 x 7 diallel cross between plants randomly selected from a segregating tetraploid setaria population (S. sphacelata var. sevicea and var. splendida) was studied at Lawes, south-east Queensland, over a two year period in two spaced plant replicates. Plants were harvested at 6-week intervals (9-10 week in winter), and dry weight and flower head number were recorded. Two additional replicates were allowed to grow uninterrupted, and date of flowering and flower head number were recorded. Damage caused by the fungus Pyricularia gvisea was scored on all four replicates. Genetic analysis indicated a high order of general combining ability variance for yield in the population and strong positive genetic correlation between seasons for yield (rg = 0.72-1.26). Variance estimates derived from analysis of variance and parent offspring regression were comparable. Genetic variance was strongly and consistently additive for days to flower and flower head number. Positive genetic correlations between seasons and years for days to flower (rg = 0.31-1.09) indicated that genetic differences in flowering were not strongly confounded by environmental effects. Dry matter yield was genetically correlated with flower head number and hence earliness to flower (rg = 0.79-1.16). Days to flower was genetically correlated with flower head length (rg = 0.71-0.91). Resistance to the pathogen Pyricularia grisea was shown to be under genetic control. The data suggested that resistance may be controlled by a gene exhibiting tetrasomic inheritance with two alleles necessary for expression of a high order of resistance.
Studies on the relationship between minerals and the development of storage breakdown in apples
Authors: Wills RBH , Scott KJ
Published: November 2004

Minerals were added to apples by injection after harvest to determine their effect on low temperature breakdown. Calcium and barium reduced breakdown and potassium, iron and copper increased breakdown. The incidence of breakdown of Jonathan apples was found to be negatively correlated with the endogenous level of calcium and magnesium and positively correlated with the level of potassium in the fruit at harvest. The most consistent indicator of susceptibility to breakdown was the ratio of potassium to calcium in the fruit.
An analysis of seed yield in some strains of subterranean clover (Trifolium subterraneum L.) when grown in binary mixtures
Authors: Rossiter RC , Palmer MJ
Published: November 2004

Two experiments using various strains of subterranean clover are described. The first experiment was conducted in the field with mixtures of Dwalganup/Northam A, DwalganupI/Daliak and Yarloop/Seaton Park, and the second in an open-sided glasshouse with Yarloop/Seaton Park. In the field experiment, the plots were grazed continuously from late July until early November when the swards were completely dry; in the glasshouse experiment, the swards were defoliated weekly until shortly after the beginning of flowering. Mixtures were arranged according to the de Wit replacement series. Seed yields for the Dwa1ganup/Northam A mixture showed the classical (de Wit) competition for the same resources, with Northam A the better competitor. On the other hand, for the Dwalganup/Daliak and Yarloop/Seaton Park mixtures there was no clear evidence of a competitive advantage of one strain over the other pair member, at least under our defoliated conditions. Whether or not this absence of 'competition' (as usually understood) is common in clover-strain mixtures is as yet unknown. We emphasize, however, that long-term success of clover strains in mixtures is not invariably associated with competitive advantage.
Shortening the irrigation interval as a means of saving water in a banana plantation
Authors: Lahav E , Kalmar D
Published: November 2004

We examined the effects of two water quantities (6600 m3/ha, which is regular commercial practice, and 5000 m3/ha) in combination with two irrigation intervals (every 3 days, which is commercial practice, and five pulses daily) on the distribution of water, nitrates and roots in the soil, and on the nutrition, growth, flowering and yield of the Dwarf Cavendish banana. With the pulsed irrigation method, the water tension in the upper soil layer is lower than that in the 3-day interval treatment and so the period of water stress for the banana plant is reduced. The pulsed system reduced soil temperature, encouraged shallower rooting, and reduced leaching of nitrates. Most of the vegetative parameters showed that suckers irrigated by pulses and with the reduced water amount were almost equal to suckers irrigated as in commercial practice. A more efficient use of water by shortening the irrigation interval was found to be a good way of saving water in banana plantations.
Relationship between plasma corticosteroids and weight change in recently parous lactating and dry sheep
Authors: Barnett JL , Star ML
Published: November 2004

Twin-bearing ewes were assigned to three treatments at lambing. Treatment 1 was the adult with both lambs retained; treatment 2 was the adult with one lamb retained; and treatment 3 was the adult alone. All sheep were fed on an amount calculated to maintain an adult and one lamb, and consequently animals in treatments 1, 2 and 3 lost, maintained and gained weight respectively. Chronic under-nutrition of the lactating ewe (treatment 1) resulted in a small increase in the maximum corticosteroid binding capacity and a large increase in total corticosteroid levels in peripheral plasma, resulting in a significant increase in biologically active (free) corticosteroid concentrations. In dry sheep (treatment 3) no such increase in free hormone concentration occurred. There was a significant negative relationship between free corticosteroid concentrations and weight change during both the 2-week intervals and the entire 6-week experimental period.
Selenium concentration in the blood of ruminants grazing in Northern New South Wales. 1. Analysis of samples collected in the National Brucellosis Eradication Scheme
Authors: Langlands JP , Wilkins JF , Bowles JE , Smith AJ , Webb RF
Published: November 2004

Bovine blood samples collected for the Brucellosis Eradication Scheme were analysed for selenium as a means of surveying the selenium status of grazing cattle in 10 Pastures Protection Board areas of northern New South Wales. Sources of error were also examined. The average standard deviation of repeat samplings from the same farm was �0.019�g selenium ml-1 and the seasonal variation in blood selenium concentration appeared to be relatively small. Relationships were calculated for predicting the selenium concentration in bovine plasma and liver, and in ovine whole blood, plasma and liver, from the selenium concentration of bovine blood; they were used to extend the survey results to grazing sheep. Samples were collected from 794 farms, and there were significant differences between Pastures Protection Board areas. Cattle in the Glen Innes and Armidale areas had the lowest selenium status with 26 and 14% respectively of herds having blood selenium concentrations = 0.02 �g selenium ml-1.
The influence of the lucerne bud mite (Eriophyes medicaginis Keifer) on the growth of lucerne
Authors: Ridland PM , Halloran GM
Published: November 2004

The influence of Eriophyes medicaginis on the growth of lucerne (Medicago sativa L.) was studied at four temperatures (15, 20, 25 and 29�C) at an initial infestation level of 10 mites per seedling, and at two temperatures (20 and 29�C) with four initial levels of infestation (2, 5, 10 and 20 mites per seedling). At 25� and 29�C, infestation with 10 mites per seedling significantly reduced dry weight of tops, stem length and the development of axillary shoots within 22 days of infestation. In this period, the numbers of mites increased 16-fold at 29OC, ninefold at 25�C and sixfold at 20�C, but there was no increase at 15�C. The extent of damage caused by mites at 20�C appeared to vary with the differences in growth of the plants under different photoperiods. Under a short photoperiod (10.3 h) where no axillary shoots developed on either infested or control plants, the extent of damage due to mite infestation was much higher than under a longer photoperiod (13.2 h) where axillary shoots developed on all seedlings. Damage symptoms on leaves of infested plants included chlorotic patches (mainly at 20� and 25�C), agate-like banding (29�C) and a waxy mottle (15�C).
The effects of length of growing season, with and without defoliation, on seed yield and hard-seededness in swards of subterranean clover
Authors: Collins WJ
Published: November 2004

The effects of length of growing season and defoliation on seed yield and hard-seededness were examined in two strains of subterranean clover (Seaton Park, Midland B) grown in swards in the field. All plots were sown at the same time and the length of growing season was varied by altering the time of finish of the season (by withholding water). There were three length of growing season treatments: T1 (short), T2 (intermediate) and T3 (control). The defoliation treatments were D0, uncut (control), and D1, defoliated at weekly intervals until the commencement of flowering. Reducing the length of growing season drastically reduced seed yield. Thus when the growing season was only 3 weeks shorter than the control (i.e. T2 compared with T3), seed yields averaged over strains and defoliations were reduced by at least one half. With a further reduction of 2 weeks in the length of the season (T1) seed yields were only about one-third of those obtained in the control (T3). The reductions in seed yield were due to reductions in both the number of mature burrs produced and to a lesser extent in mean weight per seed. Although defoliation increased seed yield in all growing seasons, the effect when measured on a relative scale was greater in T2 than in either T1 or T3. But on an absolute scale the size of the response was greater in T2 and T3 than in T1. The rate of breakdown of hard-seededness was faster in Seaton Park than in Midland B, but it decreased in both strains with increasing length of growing season.
The effect of anthelmintic treatments on growth of beef cattle in New South Wales
Authors: Smeal MG , Nicholls PJ , Webb RF , Hotson IK , Doughty FR , Harding WB
Published: November 2004

The effects of anthelmintic treatments on the growth of young beef cattle on the Tablelands and North Coast regions of New South Wales were assessed by comparing the liveweight gains of treated and untreated cattle grazing the same pasture. Anthelmintic treatments were given every 4 weeks to suppress gastrointestinal nematode infections and at strategic times. These times were at weaning (in autumn), during winter and in the late summer of the following year, and were chosen to coincide mainly with increasing worm burdens. After weaning, the mean cumulative liveweight responses of suppressively treated groups were often significantly greater during winter and early spring. Strategic treatments in winter but not in autumn also gave a significant liveweight response in some trials. Suppressively treated groups showed considerable variation in their growth rates during spring. This most likely reflected year-to-year variations in pasture growth, but the mean cumulative liveweight responses of several treated groups were significantly greater than those of untreated groups. These results suggest that helminth infections affected the growth of young beef cattle in both winter and spring. There was little liveweight response to suppressive treatments in the late summer and autumn of the second year, when the cattle were 16-20 months old. At the end of autumn, these cattle were usually 20-30 kg per head heavier than untreated cattle. Strategic treatments given in late summer to cattle grazing with untreated cattle did not produce any substantial liveweight response.
Geographic variation in the reduction of hard seed content of Stylosanthes seeds in the tropics and subtropics of northern Australia
Authors: Mott JJ , McKeon GM , Gardener CJ , Mannetje L't
Published: November 2004

The reduction of hard seed content at three sites-Katherine, Townsville and Narayen-was dominated by changes in soil temperature. The amount of soft seed formed was controlled by the number of days during which the maximum soil temperature rose above 50-55�C, and these varied with both the site and the season. From these observations a predictive relationship was developed which related hard seed content of seed samples in the field to soil temperatures. Comparison of the sites with this relationship showed three distinct patterns of hard seed reduction, with the majority of soft seed being formed in the pre-wet season for the tropics and during the early summer months for the subtropics. The importance of the predictive relationship developed with the above data was discussed in terms of patterns of germination at the field sites used.
The relative growth and development of the carcass tissues of Merino and crossbred rams and wethers
Authors: Wynn PC , Thwaites CJ
Published: November 2004

One hundred and twenty lambs were used to study the effects of breed (Merino or Dorset Horn x (Border Leicester x Merino)), sex (entire or castrate male) and liveweight (birth to 50 kg) on carcass conformation and composition. Merinos were lighter at birth and grew more slowly than crossbreds in both the pre- and post-weaning phases (P < 0.01). Rams grew significantly faster than wethers only after weaning (P < 0.01). Merinos exceeded crossbreds in height at withers and chest depth (P < 0.01), but the reverse was true for width at 'hooks' (P < 0.01) and length of pelvis (P < 0.05). Sex differences were confined to chest girth, which was greatest in wethers (P < 0.01). Eye muscle width and area were greater in crossbreds than Merinos (P < 0.01). Growth coefficients for bone and muscle calculated on the basis of both half-carcass weight and half-carcass muscle-plus-bone weight were comparable with reports in the literature. For fat, however, the coefficients were considerably higher than has been reported previously (1.938-2.010 and 2.364-2.563 for the half-carcass and the muscle-plus-bone bases respectively). When their values were averaged over the range of slaughter weights studied, crossbreds yielded more bone (P < 0.05), muscle and fat (P < 0.01) than Merinos. Rams yielded more bone (P < 0.05) and less fat (P < 0.01) than wethers. Variation in yields of muscle and fat were due largely to differences in tissue deposition in animals slaughtered at 40 and 50 kg liveweight. Partial correlation analysis indicated that changes in carcass composition were largely accounted for by differences in liveweight.
Acid phosphatase activity of intact roots and phosphorus nutrition in plants. III. Its relation to phosphorus garnering by wheat and a comparison with leaf activity as a measure of phosphorus status
Authors: McLachlan KD , Marco DGde
Published: November 2004

Eight wheat cultivars, selected on the basis of their root phosphatase (E.C. 3.1.3.4.1) activities to provide a range of phosphorus garnering abilities, experienced difficulty in taking up phosphorus from a nutrient solution containing 1 �M phosphorus, a level frequently found in the soil solution. Under the experimental conditions, total phosphorus uptake by the plants was not affected by root weight, length or fineness, nor by early plant vigour as indicated by relative leaf expansion rates during the first 3 days. With this low phosphorus source, standard root phosphatase activity was not related to phosphorus uptake but was related to total phosphorus content of the plants (r = -0.736; P < 0.01). When root phosphatase activity and total phosphorus content were determined on the same plants, the correlation was improved (r = -0.914; P < 0.001), which suggests that root phosphatase activity is a good indicator of the present phosphorus status of a plant. This suggestion was tested further by determining leaf and root phosphatase on wheat plants which were responding in yield and in phosphorus uptake to four levels of phosphorus supply. In actively growing plants, leaf phosphatase (E.C. 3.1.3.4.1) activity was better related to total phosphorus uptake (r = -0.963; P < 0.001) than was root phosphatase activity. At a second stage, where yields continued to increase but there was little change in the phosphorus content of the plant other than in its redistribution between component parts, root phosphatase was better related to total phosphorus uptake (r = -0.910; P < 0.001). Nevertheless leaf phosphatase activity was still significantly related to total phosphorus uptake (r = -0.853; P < 0.001), and could prove to be a useful measure of the phosphorus status of the growing plant. In all cases total phosphorus content and total yield were positively related (r = +0.94; P < 0.001).
Phakopsora pachyrhizi: uredial development, urediospore production and factors affecting teliospore formation on soybeans
Authors: Yeh CC , Sinclair JB , Tschanz AT
Published: November 2004

PI 230971 and TK 5 soybean (Glycine max) plants were inoculated with uredospores of P. pachyrhizi in a growth room programmed for 12-h photoperiods (2060 lux), 60-100% relative humidity and diurnal temperatures of 24 � 1�C (day) and 15 � 1�C (night). Mature uredia were observed 8 days after inoculation and new uredia continued to form for 30 days, reaching 6.2-6.3 uredia/lesion. TK 5 had maximum uredospore production at day 15, and PI 230971 at day 25 after inoculation. Between 9 and 45 days after inoculation, TK 5 produced 2386 and 12 646 and PI 230971 produced 1823 and 9396 uredospores per uredium and per lesion respectively. More telia were recorded on TK 5 than on PI 230971. The number of telia/cm2 decreased from the lower to upper leaves on the plant. Source of inoculum from either PI 230971 or TK 5 did not influence telia production. With each increase in inoculum concentration, there was a concomitant increase in telia production. Two-week-old soybean plants could be used for telia induction. Telia were produced in soybean leaves after 2 weeks at 10 and 15�C and 3 weeks at 20�C, but not at 25�C. Telia production on soybean leaves in the field was common when the daily temperature remained below 20�C for more than 15 h and the average temperature did not exceed 25�C for at least 15 days.
An analysis of the growth of mung beans at a range of plant densities in tropical Australia. II. Seed production
Authors: Muchow RC , Charles-Edwards DA
Published: November 2004

An analysis of seed production by crops of Vigna radiata cvv. Berken and CES-ID-21 and V. mungo cv. Regur, grown at a range of plant densities, indicated that the proportion of carbon assimilated during pod-filling and partitioned to the seed varied in such a way that seed yield at maturity was relatively unaffected by plant density. Seed yield of Regur was much higher than that of either Berken or CES-ID-21, and this could be attributed primarily to the longer duration of pod-filling in Regur rather than to any differences in potential pod growth rates. The data support the hypothesis that during the period of pod initiation, each viable pod requires a critical rate of supply of assimilate, and suggest that this critical rate of supply is less for V. mungo than for V. uadiata. Whilst pod number, and hence seed yield, was determined by the rate of assimilate supply during the period of pod initiation, not all the dry matter accumulated during pod-filling was partitioned to the pods. Hence seed yield in these mung bean cultivars does not appear to be determined solely by assimilate supply during pod-filling.
Population dynamics and stability of Stylosanthes hamata cv. Verano in grazed pastures
Authors: Gardener CJ
Published: November 2004

The longevity, regeneration and seed reserves of Stylosantes hamata cv. Verano were studied in grazed pastures at Lansdown, north Queensland, over a 9-year period. Stability was assessed in terms of frequency of appearance and fluctuations in botanical composition. Plants proved short-lived, with a half-life of only 3 months. The majority therefore died in their seedling year, and only 0.03 % survived to the end of the third year. In most years, S. hamata had to re-establish almost entirely from seed. Despite this, S. hamata was a highly persistent legume in the long term owing to its consistently high seed reserves and ready regeneration from seed. In one paddock, for example, it re-established in all quadrats after disappearing from 76% of them the previous year. This long-term persistence was not, however, reflected in yield stability; the content of S. hamata in one paddock changed from 6 to 68% in consecutive years. Low legume yields were recorded when seedlings of S, hamata competed poorly with the annual grasses. Higher yields occurred when more than 20 % of the population comprised perennial S. hamata plants. Retention of the perennial grasses reduced the amplitude of the fluctuations in yields of S. hamata. The perennial grass and S. hamata formed an intimate and stable association. There were only small effects of stocking rate and superphosphate on the persistence of S. hamata, which suggests that the legume is highly tolerant of a wide range of management levels, although more precise management is needed for high animal production.
Chemical changes in the wool wax of adult Merino sheep during prolonged wetting and prior to development of fleece rot
Authors: Hay JB , Mills SC
Published: November 2004

Exposure of Merino sheep to artificial rainfall (25 mm/day for 2 and 5 days or 26.7 mm/day for up to 14 days) brought about a significant loss of wool wax from the fleece. The wax remaining in the fleece after wetting was altered in its chemical composition. The proportion of the wax that dissolved in methanol had increased and an increase in the free sterol content (cholesterol, lanosterol, dihydrolanosterol and a component with the chromatographic mobility of desmosterol and lathosterol) was observed. The origin of the increased free sterol content was probably hydrolysis by bacterial enzymes but there was no parallel increase in the free fatty acid level; possible reasons for this are discussed. It is suggested that the loss of wax and decreased hydrophobic properties of the wax remaining after wetting are factors assisting the penetration of the fleece by rain and the subsequent development of fleece rot.
Insect pollination of mango in northern Australia
Authors: Anderson DL , Sedgley M , Short JRT , Allwood AJ
Published: November 2004

Large native insect species were shown to pollinate mango (Mangifera indica L.) in northern Australia. The pollinators, in decreasing order of efficiency, were wasps, bees, large ants and large flies. It was found that the most efficient pollinators were those that carried large numbers of pollen grains on their thoraces and used a short proboscis or short mouth parts to feed on nectar. Large Diptera and the native bee, Trigona sp., frequently moved from tree to tree and thus were probably the most effective cross pollinators. Of randomly selected hermaphrodite mango flowers, 36% were pollinated.
Root development in seedlings of ryegrass (Lolium perenne L.) and phalaris (Phalaris aquatica L.) sown onto the soil surface
Authors: Cornish PS
Published: November 2004

The effects of surface-sowing on root type, number and xylem radius were studied in relation to the seedling growth and survival of ryegrass and phalaris. Under optimal conditions in a growth cabinet, both species produced primary and lateral seminal roots, nodal roots and, in the absence of light, a subcoleoptile internode (s.c.i.). Phalaris had fewer lateral seminal roots and, in this species, internodal roots occurred along the s.c.i. Surface placement per se had no effect on any of the measured parameters of root development, but surface drying prevented nodal root primordia from extending, even when plants were otherwise supplied with water. This effect of surface drying on nodal root development was confirmed in a glasshouse study using undisturbed soil cores (30 by 60 cm) to simulate field conditions. Phalaris was less likely than ryegrass to produce nodal roots after surface sowing. The effective xylem radius (re) of the primary seminal root was 7.9 �m in ryegrass and 11.6 �m in phalaris. Calculations using the Poiseuille equation indicated that the axial resistance to water flow through these roots would greatly restrict seedling water uptake and growth in the absence of other roots. Lateral seminal roots and internodal roots had small vessels which could not significantly reduce the axial resistance to flow. Good seedling water relations in both species therefore depend on early development of the nodal roots which contain large xylem vessels (re > 16 �m). It was concluded that the effect of soil-surface drying on nodal root development was likely to account for some cases of poor vigour and survival of surface-sown grasses.
The nutrition of meat-type ducks. 1. The effects of dietary protein in isoenergetic diets on biological performance
Authors: Siregar AP , Cumming RB , Farrell DJ
Published: November 2004

An experiment was conducted with 1-day-old male and female White Pekin ducklings and four dietary protein levels (18, 20, 22 and 24%) from 0 to 2 weeks and eight dietary protein (%) combinations (18/18, 20/20, 24/24, 18/16, 20/16, 22/16, 24/16) from 3 to 8 weeks in isoenergetic (12.7 MJ metabolizable energy (ME)/kg) diets to determine the optimum protein level needed for maximum biological performance of meat-type ducks. At 8 weeks of age male ducks were heavier, had better feed conversion ratios and less carcass fat than females. For both sexes carcass fat increased substantially between 6 and 8 weeks. Younger ducklings had better efficiency of energy utilization than older ducks. Dietary protein levels did not affect the energetic efficiency of gain, efficiency of energy utilization and carcass composition at 8 weeks. The significant effect of dietary protein on the fat content of the wet carcasses was observed in ducklings at 2 and 4 weeks, and a similar trend was seen at 6 weeks. It is suggested that for growth rate and feed conversion efficiency, 19 and 16 % levels of protein in diets containing 12.7 MJ ME/kg are adequate to meet the protein needs of Australian ducklings from 0 to 2 weeks and 3 to 8 weeks of age respectively.
The nutrition of meat-type ducks. 2. The effects of variation in the energy and protein contents of diets on biological performance and carcass characteristics
Authors: Siregar AP , Cumming RB , Farrell DJ
Published: November 2004

In three experiments, ducklings aged 2 or 3 weeks were grown to 8 weeks of age on diets containing from 12 to 25 % crude protein, and from 11 .6 to 15.2 MJ metabolizable energy (ME)/kg 'as fed'. Generally the highest growth rates and best feed conversions were observed on diets with the highest energy content. A dietary protein content of about 12% was adequate for maximum growth, best feed conversion, and the highest protein efficiency ratio. Where comparison could be made, males grew faster than females. ME contents of the diet determined by total collection of excreta or its estimation using Cr2O3 were in good agreement. ME values for the diets declined as ducklings aged, as did nitrogen balance. Carcass protein decreased and carcass fat increased as the energy (kJ) to protein (%) ratio increased. Dressing percentage tended to increase with increasing dietary energy. Females had higher dressing percentages than males. It would appear that, for best growth rate and feed conversion, a low protein of 12-13 % and a high energy diet of about 14.0 MJ ME/kg, corresponding to an energy to protein ratio of about 1000, are adequate for ducks grown from 2 to 8 weeks. For maximum carcass lean, and minimum fat content, a low energy (kJ) to protein (%) ratio of about 600 is desirable. This corresponds to dietary concentrations of about 15 MJ/ME kg of diet and 24% crude protein.
The nutrition of meat-type ducks. 3. The effects of fibre on biological performance and carcass characteristics
Authors: Siregar AP , Cumming RB , Farrell DJ
Published: November 2004

Three experiments were conducted with male ducks and male broiler chickens to study the effects of dietary fibre on biological performance. Vegetable oil and dextrose were used to maintain diets isonitrogenous and isoenergetic in experiment 1. Both species had higher weight gains, dressed carcass weights and better feed conversion ratios (FCR) on the higher fibre and higher oil-based diets, but determined metabolizable energy (ME) was also higher on these diets. In experiments 2 and 3, weight gain was the same but feed intake and ME intake were higher, and FCR was poorer on the diets with highest fibre content. Dietary ME was lowest on these diets. Ducklings required more ME per g gain than did chickens, but utilized it more efficiently than did chickens. In both species fibre appeared to reduce availability of ME. Ducklings had less protein and more fat in the carcass than chickens. For both species, fat content of the carcass decreased and protein content increased with increasing amounts of fibre in the diet. Neither species was able to utilize dietary fibre; negative digestibility values were obtained consistently.
Estimating the association between wool and skin characters and fleece rot
Authors: Evans R , McGuirk BJ
Published: November 2004

To assess the value of skin and fleece characters as potential indirect selection criteria for increased resistance to fleece rot, estimates of the genetic correlations between the skin and fleece characters and fleece rot are needed. The characters most likely to be useful can be identified relatively cheaply and quickly by estimating the phenotypic correlation with fleece rot. This paper illustrates how phenotypic correlations with fleece rot, scored as an all-or-none character, can be estimated retrospectively from published estimates of means and standard deviations of fleece and skin characters measured in groups of sheep affected by or free from fleece rot. The paper emphasizes the incidence-dependent nature of the correlation coefficient so obtained, and points out that this must be allowed for when comparisons of correlations are made between flocks in which the incidence of fleece rot differs. This problem can be avoided by using the concept of liability to fleece rot. Data from three recently published papers are used to illustrate the main points.
Uptake by grass and transfer to soil of nitrogen from 15N-labelled legume materials applied to a Rhodes grass pasture
Authors: Vallis I
Published: November 2004

Unground legume materials labelled with 15N were applied to the soil surface under a Rhodes grass pasture in south-eastern Queensland and the recovery of the applied 15N was followed over periods of 1-3 years. Comparisons were made between two legumes, Macroptiliurn atropurpureurn cv. Siratro and Desrnodiurn intorturn cv. Greenleaf, between leaf and stem materials of different nitrogen (N) concentrations (0.5-3.8% N), and between fresh and dried materials. After 1 year, 15N in the applied materials had decreased by 25-91%, and 7-25% was recovered in the Rhodes grass. Except for leaf material of Greenleaf, these changes showed a positive, non-linear relationship to the percentage of N (%N) in the applied materials. The changes for leaves of Greenleaf were less than would be predicted from their %N. Drying Siratro leaves and stems before applying them to the soil surface did not significantly affect the above changes. For N-poor materials (0.5-1.8% N) applied at 380-1360 g dry matter m-2, uptake of 15N by Rhodes grass was greater in the second year than in the first year, whereas for N-rich materials (3.8%N) applied at 140 g dry matter m-2 uptake of 15N in the second and third years was only 23 and 12% respectively of that in the first year.
The chemical composition of seeds from some Australian plants
Authors: Rivett DE , Tucker DJ , Jones GP
Published: November 2004

The seeds from 18 Australian native plants were evaluated for their potential as food crops by assessing their nutritive values. Proximate analyses for water, protein and oil content were conducted, together with detailed analyses of the fatty acid content of the triglycerides, and of the amino acid content. Four plants, Hovea elliptica, Hardenbergia violacea, Crotalaria cunninghamii and Kennedia nigricans, were found to have a chemical composition which may have the potential for human food.
Establishment of Stylosanthes species: changes in hardseededness and potential speed of germination at Katherine, N.T
Authors: McKeon GM , Brook K
Published: November 2004

The breakdown of hard seed, germination and establishment of heat-treated and untreated seed was compared for Stylosanthes humilis, S. hamata cv. Verano and S. scabra cv. Fitzroy at Katherine, N.T. Heat treatment significantly increased yield and seedling establishment for S. hamata and S, scabra. Recovery of seed samples at the end of the wet season showed that no decrease in hard seed occurred after the first wave of seedling establishment at the onset of the wet season. This result indicates that high surface temperatures are required for seed softening, and that hard seed which has not broken by the onset of the wet season is unlikely to contribute to the sward in the season of sowing. The lack of a significant heat-treatment effect for S. humdis was attributed to the high soft-seed content (29%) in the untreated seed at the time of sowing and the loss of seedlings from the heat-treated seeds owing to rapid germination on rainfall insufficient for seedling survival. In a second experiment, the changes in seed characteristics of heat-treated seed sown in the late dry season were studied. Seed was recovered before and after each major rainfall event. Standard germination tests were carried out at near optimal conditions of water availability, light and temperature to measure potential germination speed and changes in viability. Large increases in potential germination speed occurred over 4 weeks in the field-from < 10% germination in 18 h to 70-90% in 18 h. As a result, greater than 80% of germination occurred on isolated rainfall events with less than 18-h surface moisture and were followed by rapid seedling death. We found that slow potential germination speed of sown seed did not confer permanent protection against false-start germination, since large increases in potential germination speed are likely to occur under field conditions.
Agronomic studies on Vigna spp. in South-Eastern Queensland. III. Response to sowing arrangement
Authors: Lawn RJ
Published: November 2004

The response of two accessions each of black gram (Vigna mungo), adzuki bean (V. angularis) and green gram (V. radiata) to sowing arrangement was evaluated in November, December and January sowings in south-eastern Queensland. Plants were grown in rows 100, 75, 50 and 25 cm apart with a constant within-row density of 20 plants per m, providing population densities of 200, 267, 400 and 800 thousand plants per ha respectively. Dry matter production was generally maximized at the highest population density. However, significant species x sowing arrangement and sowing date x sowing arrangement interaction occurred for seed yield. Yields of black grams were least responsive to population density/sowing date combinations, apparently because of their indeterminate growth habit. The green grams (determinate habit) and adzuki beans (weakly indeterminate) responded to progressively higher population density as sowing was delayed from November to January, reflecting progressively shorter growth duration with later sowing. In each species, yields were generally depressed at the lowest density because vegetative growth was inadequate to achieve complete canopy closure prior to podfilling. Yields were depressed at the highest density for most sowings of the black grams, and the November sowings of the adzuki beans and green grams, because of lodging. It is suggested that sowing date x sowing arrangement interactions might be used to advantage in manipulating sowing date to minimize risk of weather damage in southern Queensland.