bluuebunny/crossref_metadata_2025 huggingface dataset:
The early requirement for plant nutrients by subterranean clover seedlings (Trifolium subterraneum)
Authors: Krigel I
Published: November 2004

Growth studies of subterranean clover seedlings grown in water culture solutions revealed that the seedlings quickly exhausted the seed supplies of nitrogen, phosphorus, potassium, calcium, and magnesium. The seedlings had depleted their initial mineral reserves and were in need of additional supplies within 7 days for calcium, approximately 10 days for phosphorus, 14 days for nitrogen and magnesium, and 21 days for potassium. Nitrogen-deficient plants recovered quickly after being transferred to a complete nutrient solution. Calcium-deficient plants did not recover. Plants grown in nutrient solution that lacked phosphorus had longer roots than those affected by deficiency of nitrogen, potassium, calcium, or magnesium. For the first 45 days after germination, seedlings in phosphorus-deficient solutions developed longer roots than control plants.
Combining ability in Glycine javanica
Authors: Wutoh JG , Hutton WM , Pritchard AJ
Published: November 2004

A diallel cross of five accessions was used to estimate general and specific combining ability for nine traits in Glycine javanica L. Variation due to both general and specific combining ability was highly significant but the general combining ability component of variance was larger than the specific combining ability component for flowering time, maturity date, and seed weight. For yield, stolon length, stolon number, and percentage of stolons rooted the specific combining ability component was the larger. The cultivar Tinaroo had a high general combining ability and a low specific combining ability for most traits associated with forage yield and should be a valuable parent in future breeding programmes. Negative genetic correlations between yield and some traits associated with stolon development indicate that it may not be possible to produce a variety with all desirable characters from a breeding programme based on the five accessions used.
The softening of hard seeds of san-plain lupin (Lupinus varius)
Authors: Quinlivan BJ
Published: November 2004

Two types of impermeability were found in hard seeds of sand-plain lupin. Hard seeds with a moisture content above 10% (dry weight basis) are conditionally hard. They soften slowly when placed in a humid atmosphere or moist soil, the rate of softening varying directly with the moisture content. Moisture penetration occurs at random sites over the testa, but not normally at the hilum or strophiole. Hard seeds with a moisture content below 8.5%, on the other hand, are absolutely hard, and will not soften as a result of exposure to moist conditions. They will soften, however, if exposed to daily temperature fluctuations between 15 and 65°C, which fracture the impermeable coat at the strophiole. This type of softening does not occur in seeds with a moisture content above 8.5%. It is concluded that under field conditions the autumn germination pattern of the species, which has no physiological seed dormancy, would depend on the degree to which the seeds become desiccated during the summer. Where moisture contents remain above l0%, the seeds would give a scattered germination over several months. With moisture contents below 8.5% the only seeds capable of germinating would be those with a fracture at the strophiole resulting from summer temperature fluctuations. These would all germinate within a few days following moistening of the soil.
Effects of undernutrition in late pregnancy on the nitrogen and energy metabolism of ewes
Authors: McC Graham N
Published: November 2004

The nitrogen metabolism of five non-pregnant ewes and 16 pregnant ewes was studied. The aim was to examine the effects of pregnancy on the response to severe undernutrition. Some measurements of energy metabolism and blood composition were also made. Pregnant ewes excreted less urea nitrogen in the urine than did non-pregnant ewes when they were all well fed. When food intake was reduced by 75%, excretion by the non-pregnant ewes declined, whereas excretion by the pregnant ewes declined less or increased. After 5 days on the lower ration, pregnant ewes excreted up to 9 g more urea nitrogen daily than did non-pregnant ewes. Urea clearance was constant throughout and was 30–40% of creatinine clearance. Undernutrition caused hypoglycaemia and hyperketonaemia in the pregnant ewes only but there were no clinical signs of pregnancy toxaemia. The heat production of pregnant ewes declined when their ration was reduced. The estimated heat increment of pregnancy was greater with the reduced ration than with the large ration and it is suggested that this change represented the energy cost of gluconeogenesis and ketogenesis from protein. The gross energy content of protein apparently oxidized was estimated to be about 20% of the energy requirement of the foetus. The effects of pregnancy on nitrogen and energy metabolism and on response to undernutrition were approximately proportional to the birth weight of the lamb, and were smaller 7 weeks before lambing than 2 weeks before lambing.
Physiological and ecological studies on the oestrogenic isoflavones in subterranean clover (T. subterraneum L.). VI. Effects of defoliation including grazing
Authors: Rossiter RC
Published: November 2004

The effects of defoliating plants of different ages in different ways on the isoflavone content of the remaining leaves were investigated. When the fully expanded leaves were removed from 3-month-old plants, formononetin and genistein were reduced and brochanin A was unaffected in leaves which expanded during the subsequent 10 days. In seedlings, all three isoflavones were reduced in concentration following defoliation. But when young leaves were removed from seedlings, the isoflavones in the older remaining leaves were increased. It is suggested that severe defoliation affects soluble carbohydrate levels which in turn affect the synthesis of the isoflavones. Continuous grazing with 3–7 breeding ewes per acre had little wffect on isoflavone levels in fully expanded clover leaves.
14C translocation in orange plants
Authors: Kriedemann PE
Published: November 2004

Translocation patterns were studied by supplying 14CO2 to selected source leaves under glasshouse conditions and preparing whole plant autoradiographs. The chemical nature of 14CO2 fixation products was also examined. Within the actively growing shoots all currently expanding leaves showed strong import of 14C assimilates but no export. Fully expanded leaves, borne either on a fruitful growth cycle or on a previous growth cycle, exported assimilates principally to nearby fruits. Sharp differences existed between adjacent fruits during their early development with respect to the level of 14C incorporation. Mature leaves some distance from sites of current growth activity exported principally to the root system. Old leaves between the source leaf and roots failed to import. 14C-labelled sugars comprised the bulk of radioactive assimilates in leaf, stem, and fruit 24 hr after the commencement of feeding. In the roots, amino acids were the most heavily labelled fraction. 14C photosynthate appeared to be translocated as sucrose and it was this metabolite which occurred within the outer peel of the fruit.
Sweating rate at different body regions in cattle and its correlation with some quantitative components of sweat gland volume for a given area of skin
Authors: Pan YS , Donegan SM , Hayman RH
Published: November 2004

Sweating rates at five body regions on four Jersey and four Sahiwal x Jersey crossbred heifers were measured in a hot room under three treatments differing in temperature and duration. The correlations between sweating rate and some quantitative components of sweat gland volume for a given area of skin were examined. Differences in sweating rate between body regions, interactions between breed and body region in sweating rate, and differences in sweating rate for the various treatments were all shown to be statistically significant. There was no significant interaction between body regions and treatment in sweating rate.Between body regions within an animal, there was a positive correlation between sweat gland population density and sweating rate and a negative correlation between mean sweat gland volume and sweating rate. This negative correlation was associated with the fact that regions with high sweat gland population density also tended to have smaller sweat glands and vice versa. Indications of a positive correlation between the total sweat gland volume per unit area and sweating rate were also found, though none of these approached statistical significance.
Shoot numbers, shoot size, and yield of regrowth in three lucerne cultivars
Authors: Leach GJ
Published: November 2004

Three lucerne cultivars were grown out of doors and cut at two intensities. In the lenient intensity all shoots were cut at 5 cm from the crown, and in the severe intensity all shoots greater than 5 cm length were cut at the crown. Some plants were shaded for the 3 days prior to cutting. The change in the number and size of the regrowth shoots, and the total yield of dry matter were observed for 4 weeks after cutting.Shading the plants before cutting produced a large and uniform decrease in the weight of tops, stubble, and roots. The weights of shoots at the base of the plant, which were very small, were not consistently affected by shading. The total yield of shoots 2 and 4 weeks after cutting was not affected by the shading, although there was evidence that shoots labelled at the time of cutting did not grow so large on the shaded plants. The number of shoots remaining after cutting, the number produced during regrowth, and the size to which they grew all varied between cultivars and between cutting treatments. Shoot size depended mainly on the length of its growing period, but on plants cut severely the few shoots remaining immediately after cutting grew larger than those of the same age on leniently cut plants. The previous conclusion from work on cv. Hunter River that the yield of regrowth within lucerne cultivars depends primarily on the number of shoots and the time when each resumes growth can be extended to the additional cultivars included in the present study.
The summer nutrition of weaner sheep: The voluntary feed intake, body weight change, and wool production of sheep grazing the mature herbage of sown pasture in relation to the intake of dietary energy under a supplementary feeding regime
Authors: Allden WG
Published: November 2004

The effect on herbage intake of feeding energy-rich supplements to weaner sheep during periods of summer drought was examined in two field studies in a Mediterranean environment. The total intake of digestible energy (DE) and of dry matter (DM) by each sheep was also measured, and the relation of DE intake to body weight, body weight change, and wool production was studied under these supplementary feeding regimes. In both experiments the sheep grazed sown pastures which provided low quality mature herbage (DM digestibility 45-49 %) in plentiful amounts (> 800 kg DM/acre). A new method of estimating herbage digestibility based on direct weighings of the animal before and after a period of restricted grazing, was used in one experiment. The estimate of DM intake by this method was less by 5% than the value derived from a regression equation based on faecal nitrogen concentration. The results of the two studies were in good agreement. For each 100 g supplement (up to levels of 400 g DM/day) the intake of herbage decreased by 65-69 g. The daily digestible energy intake needed to maintain wool-free body weight was 176 kcalDE/kg W0.75 (equivalent to about 144 kcal metabolizable energy/kg W0.75). This value is substantially higher than the results recorded for pen-feeding experiments but is comparable with other results recorded for the grazing sheep. The production of each additional gram of clean wool was associated with an increased intake of 52 g digestible DM (230 kcal DE). However, because herbage intake was reduced when a supplement was fed, it was in fact necessary to provide 86 g DE as a supplement (i.e. 65 % more than is indicated by the previous value) in order to produce an additional gram of clean wool.
Efficiency of conversion of food to wool. V. Comparison of the apparent digestive ability of sheep selected for high clean wool weight with that of sheep from a random control group
Authors: Piper LR , Dolling CHS
Published: November 2004

Two groups of sheep genetically different in clean wool production have been compared for their apparent ability to digest the dry matter, organic matter, energy, nitrogen, and sulphur of a range of pelleted and chaffed diets. Differences between groups were small, variable. and in no instance significant. It is concluded that the enhanced efficiency of conversion of food to wool of the high producers is probably related to improved metabolism of nutrients after absorption from the alimentary tract.
Sulphur metabolism in sheep. II. The absorption of inorganic sulphate and inorganic sulphide from the sheep's rumen
Authors: Bray AC
Published: November 2004

The absorption of inorganic [35S]sulphate and inorganic [35S]sulphide from the reticulorumen was studied by measuring the decrease of radioactivity and decrease in sulphide concentration in the rumen and by the increase in radioactivity in the bloodstream. Normal rumen contents were replaced with buffer solution (pH 6.6). The pattern of sulphide disappearance from the rumen followed that of a first order reaction and was extremely rapid. The estimated half-life of rumen sulphide ranged from 10 to 22 min. Direct absorption from the rumen appeared to be the main mechanism involved in the sulphide loss. Under similar conditions little sulphate was lost from the rumen and absorption of sulphate across the rumen wall appeared to be negligible.
Evaluation of formaldehyde-treated casein for wool growth and nitrogen retention
Authors: Reis PJ , Tunks DA
Published: November 2004

Four sheep were given three types of casein supplements (all providing c. 16 g nitrogen per day) and the effects on wool growth rate, body weight gain, and nitrogen retention were measured. The supplements were untreated casein in the diet, untreated casein per abomasum, and formaldehyde-treated casein in the diet. Untreated casein in the diet was inferior to the other casein supplements for all parameters studied. Formaldehyde-treated casein and casein per abomasum were of similar nutritional value. The average increase in wool growth rate above the basal rate was 62% for both types of supplement; nitrogen retained was about 3 g/day, of which more than half was in wool. The treated casein was 90% digestible.
An analysis of the effects of nitrogen deficiency on the growth and yield of a Western Australian wheat crop
Authors: Halse NJ , Greenwood EAN , Lapins P , Boundy CAP
Published: November 2004

A wheat crop was grown on a nitrogen-deficient sandy soil. Urea was supplied at rates of 0 (N0), 56 (N1), and 336 (N2) kg nitrogen/ha. In general, the relative growth rate (R) decreased with time. During the first half of the growing season R for N2 > N1 >> N0, but in August deficient plants recovered rapidly. The recovery was associated with the emergence of the second tiller, an increase in net assimilation rate and nitrogen uptake, and a decrease in nitrogen stress. There was no evidence that the recovery was due to an increase in mineralization of soil nitrogen. Nitrogen stress in treatment N0 decreased from 48% in July to 14% in September. By contrast, stress in treatment N1 increased rapidly from 6 to 23% during July and fell to 5% by September. Flower initiation in N0 plants was delayed 14 days and ear emergence was delayed 8 days compared with N1 plants. The grain yields of N0 and N1 plants were 30 and 60% respectively of those of N2 plants. The decrease was due mainly to differences in the number of heads per sq metre, although nitrogen deficiency also reduced the number of grains per head and the weight per grain. The duration of photosynthetic activity after anthesis was not affected by nitrogen treatments. Harvest index was highest on N0 treatment and similar on N1 and N2 treatments.
Seasonal changes in growth and nodulation of perennial tropical pasture legumes in the field. III. Effects of flowering on nodulation of three Desmodium species
Authors: Whiteman PC
Published: November 2004

Changes in plant dry weight, leaf weight, nodule weight per plant, nodule number and size, and nitrogen content of stem, leaf, and nodules were followed throughout the growing season in Desmodium sandwicense an indeterminate flowering type, D. uncinatum which flowers in April, and D. intortum which flowers in late May. The seasonal build-up and decline of the nodule population was not related to the onset of flowering, peak nodulation occurring 3 months before flowering in D. intortum and 1 month before in D. uncinatum. D. sandwicense had three flowering periods, with some loss of nodules after flowering, but in its general trend of build-up and decline was similar to the other species. Changes in nodule weight per plant were a function mainly of changes in nodule number. The relationship between loglo nitrogen yield per plant and nodule weight per plant was similar for the three species at early samplings, but at later samplings the nitrogen yield did not increase linearly with increases in nodule weight. Thus the regression coefficient could not be taken as a constant index of nitrogen-fixing efficiency for a species at all stages of growth.
Sensitivity of annual Medicago species to manganese toxicity as affected by calcium and pH
Authors: Robson AD , Loneragan JF
Published: November 2004

Two annual Medicago species developed severe manganese toxicity symptoms at a low manganese concentration 0.3�M) in complete nutrient solution when the pH was neutral and the calcium concentration in solution was low 250�M) . Either increasing the calcium concentration to 2500�M or decreasing the solution pH to 5.4 eliminated these symptoms, decreased manganese concentrations in the tops, and increased growth. Increasing the calcium concentration in solution alleviated manganese toxicity mainly by decreasing sorption, whereas decreasing the pH appeared to act by decreasing both manganese sorption and the transport of manganese from the roots to the tops. In contrast to the Medicago species, two cultivars of T. subterraneum developed no manganese toxicity symptoms. The greater sensitivity of annual Medicago species to manganese toxicity was associated with both a higher rate of manganese sorption per gram fresh weight of roots and a lesser retention of manganese in the roots. Sensitivity to manganese toxicity may be a factor contributing to the poor growth of Medicago species relative to T. subterraneum on acid and waterlogged soils.
Fertilizer responses with non-irrigated Shiraz grapevines, 1944-1966
Authors: Tulloch HW , Harris WB
Published: November 2004

A long-term factorial trial with nitrogen, phosphorus, and potassium fertilizers was started at Nuriootpa Viticultural Station, South Australia on the grape cultivar Shiraz in 1944. Results show a significant yield response to superphosphate. Long-term applications of ammonium sulphate resulted in severe reduction of vine growth and yield, and a significant lowering of soil pH. No direct response to potassium sulphate was obtained except in one year, but a positive interaction between potassium and phosphorus occurred in some years. An analysis of the components of yield in 1964 showed that the increase in yield with superphosphate was due to an increase in the number of berries per bunch. The nitrogen, phosphorus, and potassium contents of petioles were determined and related to available reference standards.
Synthesis of microbial protein in the rumen. I. Influence of the level of nitrogen intake
Authors: Hume ID , Moir RJ , Somers M
Published: November 2004

Direct measurement has been made of the daily production of microbial protein in the rumen. When sheep were fed on a virtually protein-free purified diet, increases in the intake of nitrogen from 2 to 9 g/day increased linearly the production of protein in the rumen from 32.5 to 50.0 g/day. There was no further increase in protein production when the nitrogen intake was raised to 16 g/day. The amount of total nitrogen flowing out of the rumen showed a net increase over that ingested at daily nitrogen intakes of 2 and 4 g, no change at 9 g, and a substantial net loss at 16 g. At the lowest nitrogen intake at least 4 g recycled nitrogen was utilized by the rumen microorganisms daily. The yield of protein from the ruminal fermentation increased from 9.1 g/100 g organic matter digested in the rumen when nitrogen was most limiting, to 13.3 g/100 g when nitrogen was in excess of requirements. It was calculated that protein production in the rumen at the highest nitrogen intake was less than the potential production from the energy supplied to the microorganisms. Possible limiting factors are discussed.
Synthesis of microbial protein in the rumen. II. A response to higher volatile fatty acids
Authors: Hume ID
Published: November 2004

When sheep were fed on a virtually protein-free purified diet adequately supplied with nonprotein nitrogen, 71 g microbial protein was produced in the rumen daily. The addition of a mixture of higher volatile fatty acids (VFA) increased protein production to 81 g daily (P < 0.05). The VFA supplement also increased the molar proportions of these acids in the rumen fluid and the flow of total nitrogen from the rumen. There were no differences in nitrogen balance associated with the supplement. There were significant variations between sheep and between periods in both protein production and the molar proportion of acetic acid in the rumen fluid. A negative correlation was found between acetic acid proportions and protein production (r = -0.62, P < 0.025). The mean yield of protein from the ruminal fermentation was 13.0 g/100 g organic matter digested in the rumen. The addition of the higher VFA did not result in any appreciable increase in the efficiency of protein production from the energy available.
Effects of scrotal heating in the ram on semen characteristics, fecundity, and embryonic mortality
Authors: Braden AWH , Mattner PE
Published: November 2004

In three experiments the testes of rams were heated to 40.5�C for either 1.5 hr or 2 hr, or to 39.5�C for 4 hr; the effect on the number of spermatozoa in the ejaculate and the proportion of these that were dead or tailless was examined over the subsequent 60 days. The fecundity of the rams was tested over the same period and compared with that of the unheated rams, a total of 396 ewes being used. Spermatozoa present in the epididymis at the time of heating appeared to be unaffected, but there was considerable damage to spermatozoa developing in the testes. This was manifested by increased proportions of dead and of tailless spermatozoa between days 14 and 50 (day 0 = day of heating). In rams whose testes were heated to 40.5�C there was also a marked depression in the number of spermatozoa per ejaculate between days 34 and 47, and their fecundity was low between days 14 and 34 and was zero between days 34 and 47. Embryonic losses were estimated by comparing the number of eggs fertilized (in ewes 2 days post coitum) with the number of embryos present in ewes examined 37-42 days post coitum. In only one of the three experiments was there a significantly increased loss of embryos in ewes mated to heat-treated rams. It is concluded that, in ewes mated to heat-treated rams, embryonic losses are of minor importance compared with losses due to non-fertilization.
Changes in nitrogen and nucleic acid contents of the liver and muscle of preruminant lambs given high and low protein diets
Authors: Norton BW , Walker DM
Published: November 2004

Twenty-one crossbred lambs (aged 2-5 days) were allotted at random to three groups. A control group of six lambs was slaughtered immediately. Six lambs were given a low protein diet (diet A) and nine lambs a high protein diet (diet B). Subgroups of three lambs given diet A were slaughtered after 2 and 6 weeks on experiment; subgroups of three lambs given diet B were slaughtered after 2, 4, and 6 weeks. At slaughter the deoxyribonucleic acid (DNA), ribonucleic acid, and nitrogen (N) contents of the liver and vastus lateralis muscle were determined. It was possible, from a knowledge of the DNA phosphorus contents of these organs at different ages, to determine the relative increase or decrease in cell numbers per organ and in cell size. A comparison of (1) the comparative slaughter method and (2) the N/DNA phosphorus ratio method, for estimating the protein gain or loss from the liver and muscle, showed poor agreement between the two methods. The reason for the discrepancy was the change in the total DNA phosphorus content of the liver and muscle during growth.
The effect of leaf removal on flowering time in subterranean clover
Authors: Collins WJ , Aitken Y
Published: November 2004

The removal of fully expanded leaves delayed flowering by up to 30 days in subterranean clover cv. Mt. Barker sown in winter at Melbourne (38�S.). This effect on flowering was attributable partly to a delay in flower initiation and partly to a slower rate of leaf appearance after flower initiation. Thus leaf removal may be added to the factors already known to influence flower initiation in subterranean clover. When plants were grown under a 24 hr photoperiod. leaf removal had no effect on flower initiation; the slight delay that leaf removal caused in flowering was therefore due entirely to its effect in reducing the rate of leaf appearance. In other experiments leaf removal delayed the time of flower initiation but had no effect on the rate of leaf appearance. The effect of leaf removal on the time of flowering on the main shoot in lateral-dominant plants (as occur in the field) was qualitatively the same as in plants from which the laterals had been removed. Grazing management of subterranean clover which results in severe defoliation during early growth may delay flowering to such an extent that seed production is reduced substantially, and persistence thereby prejudiced.
Factors affecting uredospore production and dispersal in Tranzschelia discolor
Authors: Carter MV , Moller WJ , Pady SM
Published: November 2004

Uredosori of Tranzschelia discolor mature on infected twigs of susceptible peach varieties in July and uredospores are produced at a diminishing rate throughout most of the following growing season. Dry liberation of uredospores from sori on leaves occurs at a rate which increases logarithmically with the wind speed. The onset of heavy rain, or irrigation from overhead sprinklers, may cause a temporary 10-fold increase in the concentration of airborne uredospores within an orchard. In wind tunnel tests, bombardment of sori by water droplets caused liberation of uredospores at wind speeds below those normally required to release detectable quantities. The results emphasize the importance of directing control measures at prevention of the overwintering phases of the rust, which in peaches occur on twigs, and in almonds on rusted leaves retained throughout the short dormant period.
A genetic analysis of the spring-winter habit of growth in wheat
Authors: Pugsley AT
Published: November 2004

Developmental patterns of growth have been studied in nine spring and 10 winter wheat cultivars and in a number of crosses involving both groups. Among the spring cultivars five responded to vernalization while four did not. There was a very wide range in responsiveness to vernalization among the winter cultivars, ranging from the responsive Winter Minflor to Jones Fife which appeared not to respond at all to the '30-day vernalization test'. The spring habit of growth was governed by three dominant genes, any one of which was able to inhibit the expression of the winter habit. Progress has been made in establishing relationships among several spring cultivars. Those carrying the gene Sk, either alone or in combination with others, appeared to be non-responsive to vernalization. In the absence of Sk all spring cultivars so far tested exhibited a positive response. Winter selections made from spring-winter crosses always resembled the winter parent with respect to the intensity of the winter characteristic. While all winter wheats carry recessive alleles at all three loci, the differences in expression which exist between them appear to have been due to the presence of multiple recessive alleles at these loci. Further evidence of the association of leaf and spikelet numbers with days to ear emergence is presented.
The presence of methylated coumestans in annual Medicago species: Response to a fungal pathogen
Authors: Francis CM , Millington AJ
Published: November 2004

The methylated coumestans 3'-methoxycoumestrol and 4'-methoxycoumestrol previously found in perennial medics were identified in annual Medicago species. Only 4'-methoxycoumestrol was present in sufficient quantity to affect the oestrogenic activity of the medic pastures. The total coumestan content varied with species, and was higher in plants grown on gravelly soils than on sands and higher in stems than pods, but in each case there was little change in the relative proportions of coumestrol and the methylated coumestans. Infection of leaves of a common burr medic with a leaf rust (Uromyces striatus) caused a sixfold increase (from 15 to 80 p.p.m.) in the total coumestan content. The increase, measured in leaves of equal age, was clearly related to the degree of rust infection.
Quantitative inheritance studies in sugar-cane. II. Correlations and predicted responses to selection
Authors: Hogarth DM
Published: November 2004

Predicted responses to selection for a number of characters, and genotypic and phenotypic correlations between characters were studied in sugar-cane seedling populations. Predicted response from family selection was found to be much greater than from mass selection for all characters except Brix value. A selection system incorporating family selection for grade (phenotypic score) and mass selection for Brix value was proposed for further investigation. Many genotypic correlations between important characters were positive and quite high with the notable exception of the correlation between stalks per stool and weight per stalk, which was high and negative. Genotypic correlations between arrowing percentage (an undesirable character) and all other characters except stalks per stool were high and negative, but most had large standard errors.
The wool growth of Merino sheep receiving an exponential pattern of methionine infusion to the abomasum
Authors: Robards GE
Published: November 2004

The wool grown by Merino wethers infused with equal daily amounts of DLmethionine was compared with the wool grown by the same wethers while they were receiving the same quantity of methionine in an exponential pattern of infusion repeated every 6 days. The exponential pattern (8 g down to 0.5 g on the sixth day) of infusion was designed to simulate the expected flow of a once weekly dose of 'protected' methionine from the rumen to the abomasum. Initially, the wool growth of the wethers was measured while they were consuming the basal diet of oaten hay without any methionine infusion. In comparison the exponential and equal daily patterns of methionine infusion were associated with increases in wool growth of 37 and 36% respectively. Although the digestibility of the basal ration was relatively unaffected during the periods of methionine infusion both methods of infusion resulted in average nitrogen retentions greater than that from the basal ration alone.
Factors limiting the intake of feed by sheep. V. Feed intake and the productive performance of the ruminant lamb in relation to the quantity of crude protein digested in the intestines
Authors: Weston RH
Published: November 2004

The voluntary feed consumption (VFC), liveweight increase, and wool growth of lambs, initially 9-10 weeks old and weighing 22 kg, were measured over 6 weeks when pelleted diets of differing protein content were offered. The crude protein contents of the diets, on a dry matter basis, were 11.7% (LP diet), 15.8% (MP diet), and 19.1 % (HP diet). The digestion of the HP and LP diets was studied, with use of markers, in similar lambs prepared with stomach fistulae. VFC, expressed as grams dry matter/day/kg body weight0.75, was 82 (SE�3) with the LP diet, 94�3 with the MP diet, and 97�4 with the HP diet. The dietary crude protein intakes were 110, 178, and 220 g/day with the LP, MP, and HP diets respectively and the corresponding quantities of crude protein (6.25 x nitrogen in forms other than ammonia) apparently digested in the intestines (DCP,) were 75, 134, and 179 g/day. The LP and HP diets provided about 12 and 23 g DCP1/lOO g digestible organic matter respectively; the value for the MP diet was estimated to be 18 g DCP1/100 g. The rates of liveweight increase were 153 � 16, 240�9, and 267�12 g/day with the LP, MP, and HP diets respectively. Wool production was the same with the MP and HP diets but lower with the LP diet. The level of intake of DCP1 and the DCP1/digestible organic matter ratio had little effect on the gross chemical composition of the lambs, as estimated indirectly from tritiated water space. The levels of essential amino acids in peripheral blood plasma were generally in the order HP diet > MP diet > LP diet. Digesta flow from the rumen and abomasum, rumen volume, ruminal volatile fatty acid concentration, and pH of ruminal digesta were similar with the LP and HP diets. It was concluded that a level of about 18 g DCP1/100 g digestible organic matter was adequate for the expression of maximum VFC and that concentrations in excess of this would have little enhancing effect on liveweight gain or wool production under conditions of ad libitum feeding.
Resistance by cattle to cattle tick, Boophilus microplus. III. The development of resistance to experimental infestations by purebred Sahiwal and Australian Illawarra Shorthorn cattle
Authors: Hewetson RW
Published: November 2004

Purebred Sahiwal cattle acquired resistance to Boophilus microplus in a similar manner to crossbred Sahiwal cattle as previously reported. The purebred entire males and females were more resistant than a control group of crossbred steers because they dropped significantly fewer replete ticks than the crossbreds at the third and fourth, but not at the first and second infestations. Adult female ticks dropped by purebred animals were significantly lighter than those dropped by crossbred animals at the fourth infestation only. There was no significant difference in the numbers of eggs laid and hatched from ticks dropped by purebred and crossbred animals. Australian Illawarra Shorthorn steers developed resistance at a second and third infestation which waned at a fourth infestation, but individual steers displayed developing resistance throughout the four infestations. Day of modal drop of replete female ticks appeared to be affected by breed, and developing resistance or season.
An upper limit for spikelet number per ear in wheat as controlled by photoperiod
Authors: Rawson HM
Published: November 2004

In seven diverse wheat cultivars, spikelet number per main ear as influenced by day length was approaching a maximum at 30. Differences in final spikelet number between treatments and cultivars arose from differences in double ridge number at floral initiation (range from 3 to 12), in the rate of production of spikelet primordia (from 0.60 to 1.78 spikelets per day), and in the duration of production. In cultivars with a high final spikelet number, fertility towards the tip of the ear was linked with the establishment of many spikelet primordia before the appearance of glume initials and with the concurrent development of spikelets. Development of the ear of Triticale was also sensitive to day length, with the formation of up to 50 spikelets under an 8 hr photoperiod. The large number of spikelets was achieved by long duration and high rates of production, which were in excess of those for wheat under corresponding photoperiods. Suggestions are made regarding the production of more spikelets per ear in wheat.
Influence of lignin and silicon on a summative system for assessing the organic matter digestibility of Panicum
Authors: Minson DJ
Published: November 2004

The effect of lignin and silicon on the digestibility of the neutral detergent solubles (NDS), hemicellulose, cellulose, and organic matter was studied with use of 57 cuts of three cultivars of Particum coloratuni and three of Panicum maximum with known in vivo digestibilities. Lignin had only a small effect on the digestibility of NDS (r = -0.34, P < 0.05) and silicon no effect (r = +0.12, P > 0.05). The main factor controlling the quantity of digestible NDS was the percentage of NDS in the grass (r = 0.98, P < 0.001). The digestibility of both hemicellulose and cellulose was related to the lignification percentage (r = -0.88, P < 0.001). Silicondid not depress the digestibility of hemicellulose + cellulose (r = +0.29, P < 0.05). Lignin had a mean digestibility of 5.5 %. Organic matter digestibility was estimated with a residual standard deviation of � 2.2 digestibility units by summation of individual estimates of digestible NDS, hemicellulose, cellulose, and lignin. The residual variation was not related to the level of silicon (r = 0 .00). It was concluded that the main factors controlling organic matter digestibility were the percentages of both hemicellulose and cellulose present and the extent to which they were lignified. Silicon was not a factor controlling the digestibility of the structural carbohydrate fractions.
Isoflavone concentrations in the leaves of the species of the genus Trifolium, section Calycomorphum
Authors: Bailey ET , Francis CM
Published: November 2004

Seventy-six lines of various clovers, representing all extant species of the section Calycomorphum, were assayed at the commencement of flowering stage for their concentrations of the oestrogenic isoflavones formononetin, genistein, and biochanin A. All species tested contained substantial quantities of isoflavone, a characteristic rarely found outside this section. Although most species showed considerable variation in concentrations of the different isoflavones, there does appear to be a characteristic pattern for some of them, and in most of the species there was at least one line with an acceptably low formononetin concentration. T. batmanicum lines generally were high in genistein and low in biochanin A, a characteristic shared with T. subterraneum subsp. brachycalycinurn. This supports other evidence that T. batmanicum is the ancestral species of T. subterraneum, and suggests that T. subterraneum subsp. brachycalycinum may have been the earliest form of subterranean clover.
Utilization of alkali-treated straw by sheep
Authors: Hogan JP , Weston RH
Published: November 2004

Sheep were fed on a semi-purified diet based on alkali-treated straw, to determine the nutritive value of such forage and to study various aspects of microbial synthesis in the rumen. Finely ground wheaten straw was treated with sodium hydroxide, which was subsequently neutralized with acetic and mineral acids; this forage was supplemented with minerals, branched chain fatty acids, and urea, the latter increasing the crude protein content of the diet from 4 to 13%. The feed was offered to mature Merino wethers at 1000, 700, and 400 g/day. Of the organic matter consumed, 45–55% was apparently removed from the stomach. However, when the synthesis of bacterial organic matter was taken into account, the loss of dietary organic matter in the stomach was actually 64–70% of intake. The digestibility of cell wall constituents in the whole tract was 80–85% of intake, and 83–92% of this digestion occurred in the stomach. By contrast the cell contents fraction derived from the straw component of the diet was less readily digested, and only 34–44% of the amount consumed was digested in the stomach. Nitrogen from dietary urea was substantially incorporated into bacterial cells, the calculated rate of synthesis being equivalent to 2.6 to 3.7 g nitrogen per 100 g straw organic matter fermented in the stomach. Most of thenitrogen that passed into the intestines was present in bacteria, the amino acid and long chain fatty acid composition of which were similar to published figures. True digestibility of protein in the intestines was about 72%. The main parameter affected by level of food intake was the rate of flow of digesta, which ranged from 5 to 10 l/day from the rumen and from 6 to 13 l/day from the abomasum. The residence time of a soluble marker rose from 10 hr at the highest food intake to 15 hr at the lowest. The efficiency of protein synthesis was not consistently affected by changes in flow parameters. The organic matter intakes recorded, and the nutrients released from this diet were similar to those previously observed with forage diets containing 8–11% protein.
Corrigendum - Utilization of alkali-treated straw by sheep
Authors: Hogan JP , Weston RH
Published: November 2004

Sheep were fed on a semi-purified diet based on alkali-treated straw, to determine the nutritive value of such forage and to study various aspects of microbial synthesis in the rumen. Finely ground wheaten straw was treated with sodium hydroxide, which was subsequently neutralized with acetic and mineral acids; this forage was supplemented with minerals, branched chain fatty acids, and urea, the latter increasing the crude protein content of the diet from 4 to 13%. The feed was offered to mature Merino wethers at 1000, 700, and 400 g/day. Of the organic matter consumed, 45–55% was apparently removed from the stomach. However, when the synthesis of bacterial organic matter was taken into account, the loss of dietary organic matter in the stomach was actually 64–70% of intake. The digestibility of cell wall constituents in the whole tract was 80–85% of intake, and 83–92% of this digestion occurred in the stomach. By contrast the cell contents fraction derived from the straw component of the diet was less readily digested, and only 34–44% of the amount consumed was digested in the stomach. Nitrogen from dietary urea was substantially incorporated into bacterial cells, the calculated rate of synthesis being equivalent to 2.6 to 3.7 g nitrogen per 100 g straw organic matter fermented in the stomach. Most of thenitrogen that passed into the intestines was present in bacteria, the amino acid and long chain fatty acid composition of which were similar to published figures. True digestibility of protein in the intestines was about 72%. The main parameter affected by level of food intake was the rate of flow of digesta, which ranged from 5 to 10 l/day from the rumen and from 6 to 13 l/day from the abomasum. The residence time of a soluble marker rose from 10 hr at the highest food intake to 15 hr at the lowest. The efficiency of protein synthesis was not consistently affected by changes in flow parameters. The organic matter intakes recorded, and the nutrients released from this diet were similar to those previously observed with forage diets containing 8–11% protein.
Fertility and seasonal changes in liveweight of Droughtmaster cows grazing a Townsville stylo-spear grass pasture
Authors: Edye LA , Ritson JB , Haydock KP , Griffiths Davies J
Published: November 2004

An experiment was conducted to examine the fertility and seasonal changes in liveweight of cows grazing a Townsville stylo–spear grass pasture for over 4 years. There were two replicates of 12 treatments, which were factorial combinations of two stocking rates and three levels of superphosphate with and without conservation of hay. All experimental factors influenced cow liveweight. Cows on the pastures receiving superphosphate were heavier throughout the experiment than cows on unfertilized (F0) pasture; in most years there was little difference between pastures receiving superphosphate at 377 kg/ha (F3) and 126 kg/ha per year (F1). Stocking rate and conservation of hay had smaller but significant effects throughout the experiment. There were also marked seasonal fluctuations in cow liveweight associated with the amount and distribution of rainfall. Superphosphate was the only treatment that significantly affected conception and calving rate (F3 > F1, F0 at P < 0.01). Numerical analyses published elsewhere of average cow liveweight before and after mating and of conception rate strongly indicated a direct effect of superphosphate on conception rate that could not be explained by liveweight differences. This effect was primarily associated with the highest rate of superphosphate (F3), the F1 effect being more equivocal. There were significant differences between the three rates of superphosphate in the rate of change of cow liveweight during the first lactation (F3 > F1 > F0 at P < 0.05) but the differences appeared inadequate to influence conception rate markedly. Without fodder conservation, 1 cow unit to 2.4 ha was a safe stocking rate for fertilized pastures. This is three to four times the carrying capacity of unimproved spear grass pastures in the region.
Comparative nodulation, nitrogen fixation, and growth of Glycine wightii cv. Cooper and Phaseolus atropurpureus cv. Siratro seedlings
Authors: Wilson JR
Published: November 2004

The growth, nodulation, and nitrogen fixation of Glycine wightii cv. Cooper (Glycine) and Phaseolus atropurpureus cv. Siratro (Siratro) were compared in a glasshouse, sand culture techniques being used in a series of trials encompassing a full range of seasonal environments. Plants were inoculated with the commercial Rhizobium strain (CB756) for both species either at germination or 12 days later when seed reserves were virtually exhausted. In both early and late inoculation treatments, Siratro nodulated and established nitrogen fixation more rapidly than did Glycine. This difference between the species was not directly associated with the marked difference in seed size. When active nitrogen fixation was fully established, the disadvantage shown by Glycine in the early nodulation phase was not evident, and the treatments were similar in the rate of growth and nitrogen accumulation, proportion of nodule weight to whole plant weight, proportion of pigmented nodules, efficiency of nitrogen fixation, and concentration of nitrogen in the whole plant. The relatively slow initial nodule development in Glycine is probably one of the important factors hindering the field establishment of seedlings, but in subsequent growth the symbiosis appears fully effective.
Maintenance energy requirement of grazing sheep in relation to herbage availability. I. Calorimetric estimates
Authors: Young BA , Corbett JL
Published: November 2004

Grazing pressure on three pastures was adjusted so that the mean liveweights (W) of three groups of 10 Merino wethers, initially uniform, were kept at nominally 45, 35, and 25 kg. Daily rates of energy expenditure were calculated by measuring the respiratory gaseous exchanges of tracheostomized sheep in each group, and from estimates of CO2 entry rate determined during constant infusion with NaH14CO3. These measurements were made during a period of 3 weeks when the sheep had been at constant W for 9 months, and during a further 3 weeks beginning 30 days after the sheep were shorn. Further measurements were made in two periods of 7 days after animals had been interchanged between groups so that W was increasing in some animals and decreasing in others. Maintenance requirements of all sheep, indicated by the energy expenditures during the periods at constant W, were described by the equation M = 45.1 W + 256, where M is the estimated metabolizable energy requirement in kilocalories per 24 hr. Similar results were obtained during the two periods when W was changing. The requirements were in general 60–70% greater than those for housed sheep of similar W and are discussed in relation to the climatic environment, the condition of the sheep, and the availability of herbage.