bluuebunny/crossref_metadata_2025 huggingface dataset:
Ovarian response to gonadotrophin by Merino ewes selected for fecundity
Authors: Bindon BM , Ch'ang TS , Turner HN
Published: November 2004

Medium-wool Merino ewes, from groups that, as a result of selection since 1954 for this character, have a low (O group) and high (T group) incidence of multiple births, were injected with 0,375,750, or 1500 i.u. pregnant mare serum gonadotrophin (PMSG) on day 13 or 15 of the oestrous cycle (day 1 is the day of oestrus). The two groups were compared on the basis of the occurrence of oestrus, number of ovulations, ovarian follicle score, plasma progesterone level, and weight of luteal tissue. Conception rate in the two groups was compared by examining the reproductive tracts on day 20 of pregnancy, when the number and size of embryos were assessed. Injection of PMSG on days 13 and 15 gave similar results, so these data were pooled for all subsequent comparisons. Dose response lines for PMSG were constructed, the above ovarian characters being used as response types, and the curves were compared by relative potency analysis. On the basis of number of ovulations, plasma progesterone, and luteal tissue weight, PMSG was approximately three times as potent in T ewes as in O ewes. That is, for a given dose of PMSG, the T ewes produced an ovarian response three times as great as that of O ewes. At low doses of PMSG (4 1500 i.u.) the T ewes also produced more follicles in the ovary than 0 ewes. With 1500 i.u. PMSG this was reversed, since the O ewes produced many follicles that did not ovulate. The relative loss of potential embryos by day 20 was similar in the O and T ewes examined, and increased with increasing dose of PMSG. In ewes given 1500 i.u. PMSG only 20-35% of potential embryos were recovered. Embryo size on day 20 was not significantly influenced by either group or dose of PMSG. In untreated ewes the normal ovulation rate differed significantly between the O group (1.00) and T group (1.50). Ovarian data collected from untreated adult ewes of the O and T groups substantiate the differences observed in the PMSG study. It is not yet known whether the between-group differences in fecundity have arisen through changes in pituitary gonadotrophin secretion, changes in ovarian sensitivity, or both.
Preference of grazing sheep for pasture of high phosphate content
Authors: Ozanne PG , Howes KMW
Published: November 2004

Nine levels of phosphorus were applied in the autumn of two seasons to 180 plots laid out in a clover pasture. Under common grazing of the dry residues during the summer period, Merino sheep preferentially grazed the higher phosphate treatments. Selection continued to a higher level of phosphorus application than was needed to give maximum pasture growth. A less marked preference was shown for high phosphate during the growing season. Chemical analysis of the dry residues within each year showed little difference due to phosphate treatment except an increase in phosphorus concentration. This ranged from 0.08 to 0.26% phosphorus at the end of the growing season, and from 0.06 to 0.17% in the dry summer residues. Above 0.10–0.15% no marked preference for higher phosphate feed was shown. A small (20–28%) but consistent and significant decrease in the free phenol content of the pasture occurred at higher phosphate levels. and could possibly have accounted for the observed preferences.
Response to selection in Australian Merino sheep. IV.* Reproduction rate in groups selected for high clean wool weight, with a ceiling on degree of skin wrinkle and either fibre diameter or crimp frequency
Authors: Turner HN , McKay E , Guinane F
Published: November 2004

Reproduction rate (number of lambs weaned per ewe joined) and its components (proportion of ewes lambing, lambs born per ewe lambing, and lamb survival rate) are compared for 2-year-old and adult Australian Peppin Merino ewes in a random control group and two groups under selection since 1950 for high clean wool weight, with limits on high wrinkle score and either high fibre diameter or low crimp frequency. The conclusion is that there has been no correlated response in reproduction rate to selection for high clean wool weight. The difference between the selected and control groups was expressed as a percentage deviation from the control. These percentage deviations for all four characteristics fluctuated considerably and there was no consistent trend. Mean percentage deviations were calculated for ewes born in an initial period of years, soon after selection began, and a final period, at the end of the time for which data were available. Any difference between such means would indicate a selection response. For both 2-year-old and adult ewes in both selection groups, means of the percentage deviations in number of lambs weaned were negative and in most cases large during the initial period (–19.4 and –3.4 for 2-year-old and adult ewes in one group, –17.6 and –11.9 in the other), but smaller and sometimes positive in the final period (+ 4.6 and –3 30 in the first group, + 3.3 and –8.7 in the second). The main contributor to the low number of lambs weaned for 2-year-old ewes in the initial period was a low proportion of ewes lambing. For adult ewes, the number of lambs born per ewe lambing (twinning rate) was lower in the final compared with the initial period, but showed no signs of continuing to fall. The fall was compensated by an increase in lamb survival rate in the selected groups compared with the control, which was not due solely to the lower incidence of twins but was present when only single lambs were considered. Possible reasons for a lower incidence of twinning and a higher lamb survival rate are discussed. The conclusion that reproduction rate has shown no consistent change under selection for high clean wool weight would have been predicted from the zero genetic correlation between the two characteristics previously estimated in the same flock. Comparisons are made with the negative estimates of genetic correlation reported by other authors, and reasons for differences discussed. Although no negative correlated selection response has been found in these groups, it is recommended that reproduction rate should always be considered when selecting for high clean wool weight in commercial practice.

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*Part III, Aust. J. Agric. Res., 21: 955 (1970)
The seasonal incidence of Ixodid ticks on cattle in an elevated area of South-Eastern Queensland
Authors: Sutherst RW , Moorhouse DE
Published: November 2004

The seasonal incidence of the ticks Boophilus microplus and Haemaphysalis longicornis in an elevated area of south-eastern Queensland is described. B. microplus had three generations during the year, and exhibited very large increases in numbers from generation to generation in the warmer months. Despite this, the area was considered to be marginal for this species, in view of the long winter break in reproduction and the limited longevity of the larvae. The three instars of H. longicornis exhibited discrete periods of activity in the warmer months but no instar was active in the winter. Ixodes holocyclus was also recorded, but the data were insufficient to demonstrate any definite seasonal pattern of activity.
Effects of the superokra leaf gene on cotton growth, yield, and quality
Authors: Thomson NJ
Published: November 2004

No significant lint or seed cotton yield differences were found between a normal leaf cultivar of cotton and its near-isogenic superokra leaf counterpart in three experiments over three seasons at Kimberley Research Station in north-western Australia. There were also no significant interactions for lint yield of the two lines with variations in inter-row spacing and nitrogen application. Differences in quality between the two were also slight and of no commercial importance. The superokra leaf gene, however, caused earlier maturity and decreased production of leaf and stem tissue. Biologically superokra leaf was more efficient, with a greater production of seed cotton per unit of leaf tissue than for the normal leaf. Superokra leaf led to increased difficulty of weed control in conventional 1-metre cotton culture, but it appeared a desirable factor to transfer to cultivars bred for narrow-row high density cotton.
Survey observation on the mating performance of sheep in New Zealand Romney stud flocks
Authors: Quinlivan TD , Martin CA
Published: November 2004

The mating performance of 2075 New Zealand Romney rams joined singly with 127,683 ewes for three 16-day periods during the breeding season is given. These observations were conducted between 1962 and 1969 in stud flocks situated in four geographical localities based on latitude, throughout New Zealand. Area differences were observed in mean dates of first joining, in the number of ewes in oestrus, and in conception and return rates. Rams were joined with the ewes later in southern areas. When compared with flocks in the North Island, southern flocks showed a higher proportion of ewes detected in oestrus during the first 16 days of mating, higher conception rates, and lower return rates. Wide differences were observed between rams as regards the conception rate of ewes. Significant correlations between numbers of ewes joined and proportions of ewes detected in oestrus showed a quadratic rather than a linear fit, with marked differences from north to south. There were no significant correlations between the number of ewes joined and percentage conception rate.
Photosynthesis of wheat under field conditions. V.* The effect of sugar elevation on the distribution of photosynthetic activity within the crop canopy
Authors: Puckridge DW
Published: November 2004

The distribution of photosynthetic activity within the canopy of a wheat community was measured at different times of the day Plants In the field were covered by a Perspex assimilation chamber and exposed to 14CO2 and light for 15 min., then harvested and dissected. The relative specific activity and dry weight of the parts, and the calculated total carbon dioxide uptake of the community were then used to determine the distribution of photosynthesis within the community. The contribution of the lower leaves and leaf sheaths increased with increasing elevation of the sun up to 67°, while the photosynthesis of the flag leaves approached a maximum when the elevation of the sun was only 28°. The relative contribution of the ears to total photosynthesis decreased from 33 to 13% as the solar elevation increased from 17 to 67°.

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*Part IV, Aust. J. Agric. Res., 22: 1 I (1971).
The effect of defoliation on flower production in subterranean clover (T. subterraneum L.)
Authors: Rossiter RC
Published: November 2004

Three experiments were done in an open-sided glasshouse during the normal winter growing season. In experiment 1, swards of the Dwalganup strain which were severely defoliated, either after flower initiation or at early flowering, had 17% more flowers per unit ground area than uncut controls. Swards which were defoliated at both stages had 28% more flowers than the controls. In experiment 2, with single plants of the Dwalganup strain, comparable defoliations greatly decreased flower numbers per plant. The opposing effects of defoliation on flower numbers of single plants and of swards are believed to reflect opposing effects of defoliation on the rate of leaf appearance and on branching. In experiment 3, with single plants of the Dwalganup and Yarloop strains, either the young or the mature leaves were repeatedly removed before flower initiation. This delayed the date of commencement of flowering by 15–19 days; but the node of first flowering was not affected by defoliation.
Bos indicus and Bos taurus crossbred dairy cattle in Australia. I. Crossbreeding with selection among filial generations
Authors: Hayman RH
Published: November 2004

An attempt to breed a dairy animal having satisfactory milk production in a difficult environment is reported. Red Sindhi and Sahiwal (Bos indicus) males crossed with Jersey (Bos taurus) females were used as foundation breeds, and each cross was bred on to the F3 generation. All females in each generation were milked for at least one lactation. Males used as sires in each generation were chosen from progeny of the best available females. The report covers the 16 year period 1955–1970 and is based on the first lactation records of parental females and their F1, F2, and F3 progenies. Owing to the phenomenon known as "maternal instinct", the mean first lactation milk yield of each filial generation was inferior to that of the parental generation of Jerseys. The Jersey mean was 1944 kg milk in 206 days, that of F1, F2, and F3 Sahiwal x Jersey crosses 815 kg in 112 days, and that of F1, F2, and F3 Sindhi x Jersey crosses 375 kg in 83 days. Maximum first lactation yield recorded for a Jersey was 4536 kg in 305 days, for a Sahiwal x Jersey cross 4649 kg in 305 days, and for a Sindhi x Jersey cross 2694 kg in 305 days. The range in recorded milk yields among F2 and F3 Sahiwal x Jersey females indicated that selection against maternal instinct and for total milk yield would be effective.
Reactions of lines of Phaseolus atropurpureus to four species of root-knot nematode
Authors: Hutton EM , Williams WT , Beall LB
Published: November 2004

In each of two years the reactions of 36 lines of Phaseolus atropurpureus to the four root-knot nematodes Meloidogyne arenaria, M. hapla, M. incognita, and M. javanica were studied. Seven of the experimental lines were common to the two years. Two known susceptible species, Phaseolus lathyroides and Lycopersicon esculentum (tomato cv. Grosse Lisse), were used as controls. Four macroscopic and four microscopic reactions were recorded on each occasion, and the results analysed. Resistance to the four nematodes was present in all lines of P. atropurpureus. There was also evidence of differential resistance between lines; some showed increased resistance to all nematodes except M. hapla, and others showed both increased susceptibility to M. hapla and increased resistance to M. javanica. The severity of attack on thc controls was significantly less in the second ycar. Several explanations for this are advanced.
Water metabolism in desert sheep. Effects of various degrees of water restriction on the distribution of body water in Marwari sheep
Authors: Purohit GR , Ghosh PK , Taneja GC
Published: November 2004

The distribution of water in the different body compartments of eight sheep of the Marwari breed was determined after imposing the following treatments: watering ad lib., restriction to 75%, 50%, and 25% respectively of normal daily water requirements (each treatment of 5 days' duration, with a 7-day normal drinking regime between treatments), and complete deprivation of water for 3 days. The total body water, the total blood and plasma volumes, and the extracellular, intracellular, and interstitial fluid volumes of the animals began to decrease when the water intake was reduced below 75% of the normal daily requirement. A reduction to 25% normal was similar in its effect to complete deprivation, at which the plasma volume fell by 43% and the extracellular fluid volume by 33%. The findings clearly point to an unusual ability of these animals to maintain circulation even when faced with considerable haemoconcentration.
Urinary sediments in sheep feeding on oestrogenic clover. II.* Site of origin and preliminary analysis of spontaneously occurring sediments in wethers receiving fresh or dried Dinninup subterranean clover
Authors: White RR , Nottle MC , Nairn ME
Published: November 2004

Unilateral ureteric catheters were established in two Merino wethers, which were then fed on fresh subterranean clover (Trifolium subterraneum cv. Dinninup). Sediments appeared simultaneously in ureteric and urethral urines of each animal c. 3½ days after commencement of feeding, and persisted for 48 hr, when the catheters became irreparably blocked. Urine was collected from two wethers (without ureteric catheters) receiving dried Dinninup subterranean clover. Sediments appeared after 36–48 hr and persisted for 16 days while the animals received dried clover. Oestrogenicity of the fresh and dried clovers was established from histological changes produced in accessory sexual glands of the sheep. Chemical analysis of all sediments revealed a common major component, consisting of methanol-insoluble crystalline plates. These contained .calcium and on hydrolysis yielded an uncharacterized organic acid and at least one other organic component. The findings are considered in relation to previous reports and to possible functions of sediments and oestrogenic effects in the aetiology of urinary obstruction.

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*Part I, Aust. J. Agric. Res., 21: 933 (1970).
Germination of annual ryegrass seeds (Lolium rigidum Gaud.) as influenced by temperature, light, storage environment, and age
Authors: Gramshaw D
Published: November 2004

Germination of Lolium rigidum seeds, in the light (12 hr day length) and in the dark, at constant temperatures of 12, 18, and 24°C and an alternating temperature of 24/12° (12 / 12 hr), was studied in freshly harvested seeds and in seeds stored for 18 weeks. In freshly harvested seeds the highest germinability (80%) was recorded at 12° in either light or dark and at 24/12° in the light. After 18 weeks' storage, a germinability of between 95 and 100% was observed at 12° and 24/12° in the dark and at 24° and 24/12° in the light. In another experiment in which seeds from a different source were used, seeds kept in six different environments and recovered at 3-weekly intervals during a 21 week post-harvest period were examined for germinability and germination rate. The six environments were: storage in a room, storage in a 60/15°C temperature cabinet, and four field treatments in which seeds were buried 0.2 and 1.0 cm under both a bare and a mulched soil surface. Germination was tested in the light and in the dark at an alternating temperature of 24/12°. Major increases in seed germinability with age occurred during the first 9 weeks after harvest. The different environments influenced the relationship between seed age and germinability only during the first 9 weeks. Seeds located 0.2 cm beneath either a bare or a mulched soil surface during summer germinated at a faster rate than seeds kept in the other environments. These findings are discussed in relation to the germination behaviour of seeds in the field.
Sources of variation in the number of lambs born in a grazing experiment
Authors: Hedges DA , Williams WT , Wheeler JL
Published: November 2004

Considerable variation was observed in the number of lambs born to fine-woolled Merino ewes during a 4-year grazing experiment in which the factors were four pasture management systems x three stocking rates. Attempts at interpretation by standard analysis of variance were ineffectual and accordingly the data were subjected to further examination by using non-orthogonal and contingency models and pattern analysis. The strongest influence discerned was the tendency of particular ewes to consistently produce 0, 1, or 2 lambs. The majority of births (72%) were singles; twinning was relatively uncommon (<10 %) and was most prevalent in the third year; barrenness was relatively high (18 %) particularly in the first year. Significant associations were found between the number of lambs born and the ewe's liveweight and liveweight change before and after mating. Pattern analysis suggested that part of this variation was associated with differences in the initial pasture composition between plots. There was a highly significant year effect in all the relevant animal variables examined but it was not possible to separate the contributions of weight and age to this effect. It is suggested that some of the variation in reproduction rate between plots was due to non-uniform allocation of the inherently barren and twinning ewes.
Carcass composition of the water buffalo (Bubalus bubalis)
Authors: Charles DD , Johnson ER
Published: November 2004

(1) Six buffalo bulls 14–48 months old were slaughtered and subjected to detailed anatomical dissection. (2) The dressing percentage of 55.2 was greater than that in cattle of similar carcass fatness (10.6). (3) Muscle constituted 37.1% of empty liveweight. (4) The carcasses had a high proportion by weight of muscle (68.6%), a low proportion of bone (17.3%), and a low proportion of fat (10.6%) relative to the proportions found in steer carcasses of similar muscle plus bone weights or total dissected fat percentages. (5) A study of muscle weight distribution showed that the spinal muscle group formed a lesser proportion of total muscle than in bovine steers, while the muscles of the proximal forelimb, those of the thorax passing onto the forelimb, and the intrinsic muscles of neck and thorax formed a greater proportion. The possibility of a sex effect on muscle weight distribution was discussed. (6) Fat distribution featured a high proportion of intermuscular fat relative to subcutaneous fat, and the proportions of kidney and channel fats were greater than those encountered in comparable bovine steer carcasses.
A comparison of barley cultivars with different leaf inclinations
Authors: Angus JF , Jones R , Wilson JH
Published: November 2004

Under conditions of adequate moisture an erect-leaf barley cultivar, Lenta, responded to an increase in density (resulting from doubling of the sowing rate) with increases in dry matter production and in grain yield, whereas the cultivar Research, which has long lax leaves, responded with decreases in dry matter production and yield. In a study of canopy structure and its effects on light interception and utilization, it was found that in Research, with a leaf area index (LAI) of 6.1, the leaves were concentrated near the canopy surface and a relatively small proportion of the above-crop light penetrated through this layer. The net crop photosynthesis of this canopy (measured in a field assimilation chamber) was 3.8 g CO2/m2.hr when visible radiation was 313 W/m2. With Lenta (LAI 7.0) on the other hand, leaves were concentrated in the middle layers of the canopy and the light was more evenly distributed throughout the canopy. The net crop photosynthesis with the same radiation as for Research was 4.3 g CO2/m2.hr. The relative rates of photosynthesis at various levels in the canopies were determined by introducing 14CO2 into the assimilation chambers enclosing the cultivars and observing where the 14C was fixed. With Research most of it was localized near the canopy surface while with Lenta most of it was near the centre of the canopy. Of the 14CO2 taken up, 7 % was fixed in the leaf sheaths of Research and 12% in those of Lenta.
Pattern of new root production in peach trees under irrigation
Authors: Cockroft B , Olsson KA
Published: November 2004

A seasonal pattern of new root production is described for peach trees under irrigated conditions in northern Victoria. The pattern is similar to that described elsewhere for trees growing under natural rainfall or only intermittently irrigated, most root production occurring in spring with little in summer. The low root production in summer even under frequent irrigation is associated with rapid withdrawal of water from the soil following each irrigation. Irrigation criteria are discussed, since soil water levels conventionally considered adequate for leaves and fruit may be inadequate for root production.
Aetiology of the rosette and decline disease of peach and interactions between Prunus necrotic ringspot, prune dwarf, and dark green sunken mottle viruses
Authors: Smith PR , Challen DI
Published: November 2004

Rosetted peach trees were indexed for dark green sunken mottle virus (DGSMV). Although no cv. Pullars Cling trees and only 30% of trees of cv. Golden Queen were infected with DGSMV, all cv. Levis Cling trees tested were infected with it. Both Prunus necrotic ringspot (PRSV) and prune dwarf (PDV) viruses reduced shoot elongation in Elberta peach seedlings, but the viruses together reduced shoot elongation more than was expected from the effects of the viruses alone. A similar interaction occurred between mixed cultures of PRSV and PDV, that had passed through peach seed together, and an isolate of DGSMV from peach. PDV alone caused severe recurrent rosette and decline symptoms in cvv. Golden Queen, Levis Cling, and Pullars Cling, but had no significant effect on cv. Elberta.
The early vegetative growth of two annual pasture grasses (Hordeum leporinum Link and Lolium rigidum Gaud.)
Authors: Cocks PS , Donald CM
Published: November 2004

The early vegetative growth of Houdeum Iepouinum and Lolium rigidum was studied at three temperatures in a controlled environment cabinet. The seedling growth rate in each species was much more rapid during the period of endosperm availability than after cndospcrm exhaustion. At the temperatures tested (10, 17, and 24�C) the relative growth rate of Lolium was greater than that of Houdeum, with a relatively slight difference at 10 and 24�, but with a considerable difference at 17�. In spite of the superior relative growth rate of Lolium, seedlings of Houdeum were, for a considerable period following emergence, larger in terms of total weight, leaf area, root weight, root depth, and plant height because of the greater seed size. The length of this period of greater size depended on the temperature, being least (c. 26 days) at 17�C, when the advantage of Lolium was greatest. The implications of these findings in pasture production in southern Australia, and especially in the competitive relationships of Hordeum and Lolium, are described.
Breeding for improved nutritive value of Phalaris tuberosa herbage: an evaluation of alternative sources of genetic variation
Authors: Clements RJ
Published: November 2004

The variation in herbage nitrogen content and in vitro organic matter digestibility (IVDOM) among Phalaris species and hybrids, within an Algerian ecotype of P. tuherosa and among plants derived from a broadly based P. tuberosa breeding population, was examined. Variation was extensive in each of the three populations, and appears adequate for plant breeding purposes. In each population, IVDOM was negatively related to heading date. Another feature common to all populations at the heading stage was a negative relationship between WDOM and nitrogen content, demonstrable particularly when other factors having similar effects on both characters were held constant. In mature herbage of the P. tuberosa ecotype there was a positive genetic correlation between nitrogen content and IVDOM, but IVDOM at maturity was negatively related to nitrogen content at heading. Annual Phalaris species had higher average IVDOM values at heading (mean 70.5 %) than perennial species (mean 66.1 %) when data were adjusted to a common heading date. Although there was considerable intraspecific variation, only the annual species were sufficiently superior to the best P. tuberosa strains to warrant consideration for hybridizing with P. tuberosa. Since such hybrids have reduced perenniality, and are cytologically unstable, interspecific hybridization appears to have the least value as a source of herbage quality for a P. tuberosa breeding program. In addition, annual species were lower in nitrogen content (mean 1 .15 %) than perennials (mean 1.70 %) at a common heading date. Estimated heritabilities of IVDOM and nitrogen content of mature herbage of the P. tuberosa ecotype were 0.78 and 0.59 respectively, for a family mean based on replicated eight-plant rows. Genetic statistics indicated that a substantial response to selection for improved digestibility of mature herbage would be accompanied by a correlated increase in IVDOM at heading, a slight increase in nitrogen content at maturity, a decrease in nitrogen content at heading, little change in heading date, and perhaps some increase in the weight of individual tillers. Response to selection for increased nitrogen content would be small, and would be accompanied by a reduction in tiller weight. Individual plants derived from the broadly based population ranged from 56 to 76% IVDOM at the heading stage. This population, because of its agronomic superiority, is considered to be the most suitable source of genetic variation on which to base a breeding program.
A laboratory spraying apparatus
Authors: Abdelrahman I
Published: November 2004

A laboratory spraying apparatus is described. It consists of an atomizer carried on a mechanical carriage that moves at constant speed back and forth at a fixed height above the target; after each passage the carriage is moved forward on another carriage. A large area (about 30 by 60 cm) can be sprayed in this way. Tests of the performance of the apparatus showed it to be capable of giving a reasonably even and reproducible deposit of spray over the target area. A method for converting the dose in percentage concentration to quantity per unit area is presented.
Associated changes in the attributes of wheat populations mass-selected for seed size
Authors: Bhatt GM , Derera NF
Published: November 2004

Evaluation of wheat populations mass-selected for seed size was made [or agronomical and quality characters in F2 and FQ generations of the crosses. Estimates of means and variances for these characters and their correlation with seed size were obtained to study the correlated response to selection for seed size. The expression of quality characters (test weight, milling extract, wheat protein, flour protein, and kernel hardness) was found to be independent of the expression of seed size in all the crosses studied. In the case of agronomic characters, however, the crosses behaved differently so far as the correlated response was concerned. It was concluded that in the crosses studied, mass selection for seed size could be practiced with certain associated advantages and without adverse response for most of the characters of economic significance in wheat.
Effects of surface moisture supply on the subsoil nutritional requirements of lucerne (Medicago sativa L.)
Authors: Simpson JR , Lipsett J
Published: November 2004

During glasshouse experiments, lucerne plants were grown in deep (85 cm) reconstituted profiles of a granitic soil. The plants were subjected to controlled degrees of drought in surface layers, while a water table was maintained at 85 cm depth. The effect of placing monocalcium phosphate, sodium borate, and calcium carbonate (lime) in the moist subsoil (55 cm depth) was compared with that of application to surface layers, either frequently moistened or dry. Within 8 weeks of commencing surface drought the phosphorus concentration in the shoots had fallen to much lower levels than that in plants grown in surface-moist soil. Deep placement of monocalcium phosphate increased the phosphorus content and yield of the droughted plants, but the effects were greatly enhanced when the deep phosphate band was placed within a soil layer amended with lime and borate. These nutritional effects did not occur with surface-moist plants. The evidence indicated that the combined placement of phosphate, lime, and borate in the subsoil was particularly effective because of a marked increase in lateral root proliferation within the amended layer. Lime did not appear to influence phosphate availability directly through soil chemical effects. The results emphasize the importance of subsoil nutritional characteristics in stabilizing lucerne yields over intermittently wet and dry periods.
The effect of defoliation on flowering and seed yield in subterranean clover
Authors: Hagon MW
Published: November 2004

The effect of defoliation on flowering and seed production in Woogenellup subterranean clover was studied under sward conditions. Defoliation prior to floral initiation (FI) delayed this event but did not alter the time from sowing to flowering compared with the undefoliated control. However, defoliation between FI and flowering reduced the time from sowing to flowering by 10 days. These findings are discussed in relation to the changes in rates of leaf appearance which resulted from defoliation. Defoliation of the plots either before FI, after FI, or at early flowering did not alter seed yield or any of its components.
Calcium requirements of the young lamb. I. Effects of different intakes of dietary calcium on liveweight gain, bone development, and blood serum calcium levels
Authors: Hodge RW , Pearce GR , Tribe DE
Published: November 2004

Four groups of male lambs were fed on liquid diets to give them four different calcium intakes (50, 250, 450, and 650 mg calcium/kg liveweight/day) from 5 to 70 days of age. Dry matter intake, liveweight gain, and serum calcium levels (but not food conversion efficiency) were reduced in those animals consuming 50 mg calcium/kg/day, but there were no significant differences between the lambs receiving 250, 450, or 650 mg/kg/day. Femur development in the lambs consuming 50 mg/kg/day was inadequate: the bone was brittle and tended to fracture. Although femurs taken from the animals receiving 250mg/kg/day were not fully developed, they appeared to be structurally sound. It is concluded that a calcium intake of 250 mg/kg/day is likely to be adequate for young lambs slaughtered for meat production at an early age.
Calcium requirements of the young lamb. II. Estimation of calcium requirements by the factorial method
Authors: Hodge RW
Published: November 2004

Four groups of lambs received liquid diets providing 50, 250, 450, and 650 mg calcium/kg liveweight/day between 5 and 70 days of age. Calcium balance measurements were used to determine the retention and apparent availability of calcium. Retention was also estimated from cohort slaughter analyses. Estimates were made of dietary calcium requirements for lambs of 10 kg and 18 kg liveweight gaining weight at 100, 200, 300, and 400 g/day. These estimates for lambs of 10 kg liveweight were 1.0, 1 .9, 2.9, and 3.9 g calcium/day and for lambs of 18 kg 1.2, 2.4, 3.6, and 4.8 g calcium/day respectively.
Effect of temperature during flowering on seed formation of Stylosanthes humilis
Authors: Skerman RH , Humphreys LR
Published: November 2004

A Greenvale line of Stylosanthes humilis was grown in controlled environment cabinets and subjected to various temperature treatments after commencement of flowering. Seed yield was maximal (8.0 g per plant) at 31/31�C; it reduced to 6.3 g at a 24�C nyctotemperature, and to 1.0, 1.2, and 0.06 g per plant at day/night temperatures of 31/17, 24/17, and 17/17� respectively. Few seeds were formed at a 10� nyctotemperature. The rate of inflorescence differentiation was positively related to nyctotemperature; seed formed per inflorescence was apparently maximal at a 24� nyctotemperature and sensitive to low phototemperature. The whole-plant yield of this annual plant was highest at 31/17 and 24/17�, in which treatments flowering was reduced. Some ecological implications are discussed.
Effect of diphenylamine on the incidence of low temperature breakdown in apples
Authors: Wills RBH , Scott KJ
Published: November 2004

Diphenylamine (DPA), injected into the core of Jonathan apples, increased the incidence of low temperature breakdown in fruit which had developed breakdown after 20 weeks in cool storage, but had no effect on fruit which did not develop breakdown until after 40 weeks. Applications of DPA early in storage were less effective in inducing breakdown than late applications. These effects were attributed to a gradual loss of DPA from the flesh tissue during storage, and to the action of DPA on the terminal reactions of the metabolic pathway which produces breakdown.
Effect of changes in nutritional level on the depth and curvature of wool follicles in Australian Merino sheep
Authors: Nay T , Jackson N
Published: November 2004

Follicle depth and follicle curvature, measured by quick and simple techniques, were tested out on samples taken from sheep kept on a varied plane of nutrition. Follicle curvature was found to be highly repeatable. Follicle depth proved less reliable.
A preliminary agronomic evaluation of Stylosanthes species
Authors: Edye LA , Burt RL , Williams WT , Williams RJ , Grof B
Published: November 2004

The relative merits of morphological and agronomic attributes for the classification of cultivars are discussed, and reasons are given for suggesting that a purely agronomic classification would be a valuable supplementary technique. A polythetic divisive program was used to classify 272 Stylosanthes accessions which had been grown in three spaced-plant experiments. Eleven agronomic attributes were used, and the agronomic groups generated were compared with the morphological-agronomic groups previously reported. The two classifications were broadly in agreement for all species except S. guyanensis, in which the agronomic classification revealed important variation. It is shown that the agronomic classification is an effective means of detecting agronomic heterogeneity within a morphological-agronomic group, and is particularly useful in elucidating inter-site differences in performance. It is suggested that the double classificatory approach provides a systematic method for the preliminary evaluation of accessions, and a rational means of selecting accessions for further experiments.
Host range and physiologic specialization in Rhynchosporium secalis
Authors: Ali SM , Boyd WJR
Published: November 2004

The pathogenic variability of isolates of R. secalis collected in Western Australia has been examined on different host genera of the Gramineae and on selected barley cultivars. Depending on the host-isolate combination and the conditions of the test, evidence has been obtained of inter- and intra-isolate variability in both host reaction and isolate pathogenicity. This complicates definitive interpretation of the results, militates against identification of conventional 'races' of the pathogen and shows that R. secalis does not exhibit strict host specialization. Hosts which consistently express resistance or susceptibility under different environmental conditions, and isolates which express their pathogenic characteristics consistently, have been identified. The need for more precise genetic studies and adequate sampling of genetic diversity is emphasized.
The importance of environmental factors in soil fertility assessments. II.* Nutrient concentration and uptake
Authors: Stefanson RC , Collis-George N
Published: November 2004

Lettuce plants were grown in two soils under a wide range of controlled conditions in the glasshouse. Assessments were made of the effect of soil temperature, incident light and season, in terms of the nutrient concentration and nutrient uptake in the plant tissue, which was analysed for nitrogen, phosphorus, potassium, magnesium, calcium and sodium. Both the concentration and the uptake of each nutrient were affected significantly by soil temperature and incident light, both between and within seasons. The type of soil had an effect on these estimations, but its significance could not be tested statistically. A considerable number of first and second order interactions between components of the physical environment affected the quantities being examined. These interactions were statistically significant. The value of each nutrient analysed, which is an aspect of plant performance, reflected changes in the physical environment independently of the other nutrients. Often a particular nutrient showed no coincident pattern of responses to the environment when these were measured in terms of dry weight, nutrient concentration in the tissue, or total nutrient uptake. Each nutrient concentration and each nutrient uptake varied as micrometeorological factors in the glasshouse changed. Hence, ambiguous assessments of soil fertility were obtained with all measured plant responses.

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*Part I, Aust. J. Agric. Res., 25: 299 (1974).
The effects of exogenous progestagen and oestrogen on cervical mucus in the ewe
Authors: Croker KP , Shelton JN
Published: November 2004

The production of mucus during the pro-oestrous and oestrous phases of the oestrous cycle, and the moisture content of the samples, were measured in normal cyclic ewes and in ewes in which the time of oestrus and ovulation were controlled by the application of Cronolone-impregnated intravaginal sponges, either alone or with the concurrent injection of 1 µg, 5 µg, or 25 µg oestradiol-17G (E2) per day from the day of sponge insertion until the day before sponge withdrawal. The average duration of oestrus was not affected by the treatments. Production of mucus and the percentage of moisture in the samples in the Cronolone-treated ewes were depressed following the injection of the higher doses of oestrogen. The content of dry matter in the mucus sample declined throughout the observation period in all groups apart from that which received 25 µg E2/day. The possible role of the changes in mucus characteristics recorded in this experiment is discussed in relation to the transport of spermatozoa into and through the cervix.
Kinetics of phosphate absorption by intact rice plants
Authors: Fageria NK
Published: November 2004

Phosphate absorption by intact rice plants was found to be mediated by two distinct mechanisms when studied over a range of phosphate concentrations from 0.16 to 161µM . A low concentration, high affinity (Km = 1.4 x 10-6M) mechanism becoming saturated at about 2.5 x 10-6M phosphate, and a low affinity (Km = 7 x 10-6M) mechanism operative at higher phosphate concentrations were observed. The role of both mechanisms in phosphate absorption by plants growing in the soil is discussed.
Superphosphate utilization in clover ley farming. I. Effects on pasture and sheep production
Authors: Kohn GD
Published: November 2004

From 1962 to 1966 an experiment was carried out at the Agricultural Research Institute, Wagga Wagga, N.S.W., with dry Merino sheep on an annual clover-grass pasture, in which the stocking rate and the rates of topdressing with superphosphate were varied. In the first year Trifolium subterraneum (subterranean clover) responded to superphosphate, particularly at the lowest stocking rates. In the following 2–3 years there was a change to Hordeum leporinum Link (barley grass) dominance. A greater amount of subterranean clover persisted over the years on the unfertilized plots than on the fertilized plots. Clover burr on these treatments was associated with better liveweight performance by sheep over the dry summer-autumn period. However, after the autumn rains germinating barley grass on the topdressed plots allowed rapid liveweight gains to be made by the sheep on those treatments. Greasy wool production per head, averaged over four shearings, was 4.81, 4.36 and 3.86 kg at 5, 10 and 15 sheep per ha respectively. Superphosphate had no significant effect on wool production. Liveweights decreased as the stocking rate increased. However, at a given stocking rate, the liveweight changes were influenced by changes in pasture composition induced by topdressing with superphosphate, as much as by total available pasture. It appears that in this clover ley farming area topdressing can be omitted in the pasture phase of a wool production system after 700 kg superphosphate ha-I have been applied to the soil.
Meat production of Friesian steers: the effect of intramuscular fat on palatability and the effect of growth rates on composition changes
Authors: Purchas RW , Davies HL
Published: November 2004

The relationship between intramuscular fat percentage and beef quality was investigated in 36 Friesian steers. A poor relationship between fatness and age was ensured by having six groups on rations increasing in concentrate content from 10 to 80%, and then slaughtering the animals after 300 days on these rations at an age of c. 17 months. The group means ranged from 202 to 276 kg for carcass weight, from 2.4 to 6.8 mm for fat depth at the 12th rib, and from 1.5 to 3.4% for intramuscular fat of M. longissimus. Up to 38% of the variation in shear force of M. longissimus could be accounted for by variation in intramuscular fat percentage but in the case of M. rectus femoris and of samples from M. semitendinosus, which had not cold shortened, the relationship between shear force and intramuscular fat percentage was not significant. These results suggest that intramuscular fat may influence tenderness through an effect on susceptability to cold shortening. Taste panel results indicated that with increased intramuscular fat percentage, the flavour, tenderness and overall acceptability of M. semimembranosus roasts improved, but there was little change in juiciness. There was no indication that differences in intramuscular fat percentage were associated with differences in muscle collagen concentration, collagen solubility, ultimate muscle pH, or adrenal cortex activity. Allometric coefficients relating measures of composition to carcass weight indicated that changes in composition with increases in carcass weight were more rapid than those reported for other growth studies. It is suggested that this was because the level of nutrition and carcass weight both contributed to the differences in composition.
Analysis of the nature of interference between plants of different species. I. Concepts and extension of the de Wit analysis to examine effects
Authors: Hall RL
Published: November 2004

Both competitive and non-competitive processes may strongly influence the growth of plants in a multispecific community, though the latter, particularly in experimental studies, are often overlooked. A method of analysis, based on the principles of the de Wit model, is suggested which may enable . the factors involved in both competitive and non-competitive aspects of interference between species to be identified.
Potential production of grass and clover monocultures in a mediterranean-type environment — an experimental approach
Authors: Cocks PS
Published: November 2004

Monocultures of Lolium rigidum cv. Wimmera and Trifolium subterraneum cv. Woogenellup were established at four densities and mown at three contrasting heights over a 5 month period. Heavy applications of fertilizer were applied to eliminate nutrient deficiencies. Dry matter yields and leaf areas were measured before and after the 3-weekly defoliations, and shoot numbers before the defoliations. Growth rate was related to leaf area index (LAI) in all but one of the sampling periods. Maximum growth rates were proportional to light energy, and the average efficiency of conversion was 4.5% for the clover and 5.5% for the grass. Total herbage yields as high as 17.3 t ha-1 were obtained from the grass, and up to 16.4 t ha-1 from the clover. The results are discussed in relation to the differential ability of grass and clover to exploit the environment. The grass was leafier and had more shoots, but it is thought that clover intercepted more of the incident light at low LAI. The results indicate that potential yields would be reduced at the low LAI values associated with an efficiently utilized pasture.