bluuebunny/crossref_metadata_2025 huggingface dataset:
Establishment, persistence and production of lucerne-perennial grass pastures surface-sown on hill country
Authors: Campbell MH
Published: March 2005

In a series of experiments on unploughed hill country near Turondale, New South Wales, the effects of rate and type of herbicide on establishment, survival and persistence of surface-sown Medicago sativa, Trifolium subterraneum, Dactylis glomerata and Phalaris tuberosa were ascertained. Measurements of plant density and dry matter production of the pasture under grazing were made for up to seven years after sowing. Establishment was achieved under various rainfall conditions from eleven sowings. Herbicide application proved essential for the establishment and survival of the perennial species. Survival of M. sativa seedlings through their first summer was greater on the 2,2-DPA treatments than on paraquat treatments. The addition of simazine to paraquat increased survival of M. sativa over that on the paraquat-alone treatment. No similar effect was observed when simazine was added to 2,2-DPA. Establishment and survival were not influenced by rates of 2,2-DPA between 4.1 and 12.4 kg a.e. ha-1. Plant density in established swards was increased by up to 1200 per cent by strategic grazing applied after the improved species had completed seeding. Lucerne dominated other species and in the final year of measurement produced 87 per cent of a mean dry matter production of 9719 kg ha-1.
Effect of nitrogen fertilizer on a kangaroo grass (Themeda australis) grassland
Authors: Fisher HJ
Published: March 2005

Three rates of nitrogen fertilizer and a standard superphosphate dressing were applied to a Themeda australis grassland with and without broadcast seed of Dactylis glomerata. Two cutting frequencies were imposed and dry matter yields and botanical composition were measured. T. australis responded to nitrogen, but the response was not sufficient for it to predominate over other species, particularly Poa labillardieri, as it had done under low fertility conditions. P. labillardieri yields increased markedly with increasing nitrogen rate. D. glomerata, which established only where nitrogen fertilizer was applied, substantially reduced the increase in P. labillardieri at the high level of nitrogen. Cutting frequency affected botanical composition in degree but not in kind. Both P. labillardieri and D. glomerata yielded less, but T. australis yielded more under more frequent cutting. For pasture improvement in wetter parts of the southern tablelands of New South Wales, it is important to establish a perennial grass at the beginning of the programme to reduce the growth of the undesirable tussock. P. labillardieri.
The effect of sulphate on the selenium content of pasture plants
Authors: Pratley JE , McFarlane JD
Published: March 2005

In the three experiments reported, the selenium content of pastures was shown to be substantially affected by applications of sulphate fertilizer. Where pasture yields responded to sulphur topdressing, selenium levels in the legumes present were reduced by as much as 50 per cent due largely to yield dilution effects. On a second site, where pasture responses to sulphur were not obtained, selenium levels were also depressed, in this case indicating the existence of an antagonism between sulphur and selenium. A subsequent nutrient solution culture experiment indicated that an antagonism existed between sulphate and both selenate and selenite forms, with the effects being much stronger in the case of the selenate. The implications in animal production of the effects of applied sulphur on pasture selenium levels and of the associated increases in pasture sulphur levels are discussed.
Effects of glyphosate on the germination and establishment of surface-sown pasture species
Authors: Campbell MH
Published: March 2005

Seeds of Medicago sativa, Trifolium subterraneum, Lolium perenne and Phalaris tuberosa were sown on bare soil before spraying with glyphosate, or surface-sown onto existing pasture 0, 7, 14 and 35 days after the pasture had been sprayed. Rates of glyphosate used were 0, 1.5 and 4.5 kg a.e, ha-1. Germination and establishment were recorded for seeds on the bare soil and seeds in the sprayed pasture under glasshouse conditions. Residual glyphosate had no important effects on germination but had deleterious effects on establishment, particularly of the legumes. The residual effects were less severe at the low rate and disappeared 35 days after spraying
Lamb mortality under three lambing systems
Authors: Tyrrell RN , Giles JR
Published: March 2005

Three systems of lambing management were compared at Trangie in Central Western New South Wales. A supervised system involving daily drifting of ewes through a series of small paddocks was first compared with an unsupervised system in which ewes were set-stocked in a single large paddock (A) and later, an unsupervised system in which ewes were set-stocked in sub-flocks according to their expected date of lambing (B). Lamb loss associated with the management of marking and mulesing proved to be an important factor in the comparison. The introduction of unsupervised system (B) was associated with a reduction in losses after marking compared with the supervised system. Lamb loss prior to marking was lowest in the supervised system. Of the three systems, unsupervised system (B) is considered the most suitable for areas in which environmental conditions during lambing are not harsh.
Persistence of several annual legumes in mixtures under continuous grazing in the south west of Western Australia
Authors: Taylor GB , Rossiter RC
Published: March 2005

Two experiments are described: one in the wheatbelt in areas receiving 320 and 400 mm average annual rainfall, and the other in a medium rainfall area with an average rainfall of 640 mm. In the first experiment various combinations of barrel medic (Medicago truncatula) and cupped (Trifolium cherleri) and rose clovers (T. hirtum) with subterranean clover (T. subeterraneum) were grown at four sites. Each site was continuously grazed by sheep for periods ranging from three to five years. At all sites subterranean clover became dominant within a few years of establishment. The second experiment involved rose and subterranean clovers in ungrazed pure swards and mixed swards which were either grazed or ungrazed. Grazing was continued for three years. Grazing had a profound effect on the composition of the mixture: whereas subterranean clover dominated the grazed sward, in the absence of grazing rose clover over-topped the subterranean clover and dominated the mixture. The success of subterranean clover in grazed mixtures is attributed largely to relative inaccessibility to the grazing animal, particularly of seedlings but also of seeds.
Further sources of resistance to common root rot (Cochliobolus sativus) of wheat
Authors: Wildermuth GB
Published: March 2005

One cultivar of einkhorn, one cultivar of emmer, three cultivars of durum and 43 cultivars of bread wheat were screened for resistance to common root rot (Cochliobolus sativus). The emmer cultivar, Yaroslav and the white-grained bread wheat cultivars, Festival and Mexico 120, showed a high level of resistance. This is the first record of resistance in white-grained cultivars and the advantage of using whitegrained rather than red-grained cultivars as sources of resistance in Australia is indicated. It is considered that the major source of resistance in Festival, Gamut and Spica has been derived from Pusa cultivars.
Short term effect of some methods for improving soil structure in red-brown earth soils of the northern irrigation areas, Victoria
Authors: Mehanni AH
Published: March 2005

Deep ripping, deep ripping with mixing, adding gypsum or organic matter, and the use of deep rooted plants such as lucerne had some effect in improving the structure of a Lemnos loam profile with a compacted clay subsoil. Measures of plant performance and soil properties showed the effects of mechanical methods and chemical or biological methods were independent of one another. The greatest effect was from the addition of gypsum which changed the balance of the exchangeable cations and substantially increased the aggregation of the soil.
Effect of mechanical defoliation on botanical composition and yield of a Townsville stylo-sabi grass sward
Authors: Ive JR
Published: March 2005

A sabi grass (Urochloa mosambicensis)-Townsville stylo (Stylosanthes humilis) sward on cleared land at Katherine, Northern Territory, was mechanically defoliated for three seasons. The wet season defoliation treatments were no defoliation, late light, early heavy, and regular heavy. The sward's defoliation responses were measured in terms of dry matter production, quality, and botanical composition. In the non-defoliated treatment, sabi grass was highly competitive and this grass dominance was not reduced by any of the mechanical defoliation treatments studied. The legume dry matter proportion declined consistently from an initial all-treatment mean of 66 per cent to 9 per cent in the third season. Annual grasses failed to colonize the sward. Sabi grass dry matter yield was unaffected by defoliation in the first season, although plant vigour was reduced resulting in yield reduction in subsequent years. Townsville stylo and total dry matter were reduced by heavy wet season defoliation. Legume weighted mean phosphorus concentration was increased by heavy defoliation, but sabi grass mean phosphorus concentration, although higher than for Townsville stylo, was variable and seasonally dependent. Weighted mean nitrogen concentration was generally higher with heavy defoliation for both Townsville stylo and sabi grass, although the legume nitrogen concentration was approximately twice that of sabi grass.
Reproductive activity in beef heifers following post-weaning feeding on spear grass hay alone or with supplements
Authors: Siebert BD , Field JBF
Published: March 2005

A group of 24 heifers was weaned, divided into three groups of eight and pen-fed during the dry season in north Queensland (Lat. 18�S). One group, which received poor quality native pasture hay only, lost body weight. Another group, which received in addition a small portion of legume hay in the diet, gained body weight slowly. The third group received a further addition of legume hay plus cereal grain and gained body weight more rapidly. During the following wet season all animals were allowed to graze and the occurrence of oestrus was noted. Only two heifers in the poorly fed group exhibited oestrus. Six heifers in each of the other groups exhibited oestrus, but those that were better fed exhibited oestrus cycles for a longer period. Following this grazing period, all animals were slaughtered and analysed for the major chemical components.It was concluded that only small improvements in nutrition need be made during the tropical dry season to increase protein and energy intake sufficiently to support body weight gain. During subsequent grazing marked changes in oestrous activity can result from such improvements. The onset of oestrous appeared closely related to body fat content.
Diagnostic leaf analysis for stone fruit. 4. Plum
Authors: Leece DR
Published: March 2005

Changes in the leaf composition of Prunus domestica cv. D'Agen and P. salicina cv. Mariposa, were measured monthly during the 1971 -72 and 1972-73 seasons in New South Wales. The rate of change of leaf composition was least during January-February for D'Agen and during December-February for Mariposa. Thus, leaf composition standards should be based on January-February samples for D'Agen and December- February samples for Mariposa, and diagnostic sampling should be confined to these periods where possible. Correction factors for adjusting the composition of early or late samples back to January 31 levels, were calculated for D'Agen from polynomials with time fitted to the leaf composition data. A survey of the leaf composition of well-managed orchards was also conducted each January from 1971 to 1973. Of the European prune orchards surveyed, 51 per cent were low in nitrogen, 37 per cent were low in phosphorus, 28 per cent were low in iron, 25 per cent were high in copper, 10 per cent were high in manganese and 23 per cent were high in boron. Of the Japanese plum orchards surveyed, 33 per cent were high in nitrogen, 14 per cent were high in potassium, 22 per cent were low in calcium, 18 per cent were high in copper and 15 per cent were high in manganese.
Trichostrongylosis and wool growth. 3. The wool growth response of resistant grazing sheep to larval challenge
Authors: Barger IA , Southcott WH
Published: March 2005

Wool growth rates of grazing sheep that were resistant to infection with the intestinal nematode Trichostrongylus colubriformis were measured in the presence and absence of a larval challenge. In one experiment, resistant sheep exposed to a moderate level of larval challenge grew 11 per cent less wool than unchallenged resistant sheep grazing the same paddock. A second experiment confirmed the previous results but showed that the magnitude of this wool growth depression did not depend on the severity of the challenge
Some effects of three glucocorticoid analogues on wool growth and their efficacy as defleecing agents in sheep
Authors: Panaretto BA , Chapman RE , Downes AM , Reis PJ , Wallace ALC
Published: March 2005

Some effects of the parenteral administration of three glucocorticoid analogues, namely Opticortenol (dexamethasone-21 -trimethylacetate), Decadron phosphate (dexamethasone-21 -phosphate) and the heterocyclic corticosteroid, Cortivazol, were observed on wool growth in sheep. None of the glucocorticoids was satisfactory for defleecing sheep, principally because of variation between sheep and between body regions in the wool growth response. Four main types of response to dosing with glucocorticoids were observed : Firstly, with some animals there was no obvious effect on wool growth. In a second category there was a well-defined 'break' in some wool fibres but the fleece as a whole was retained by other unbroken fibres. Thirdly, complete or partial shedding of the fleece was seen, unshed portions usually being present on the head, neck and shoulder regions and consisting mainly of broken wool fibres but also a proportion of whole fibres. Finally, prolonged wool growth depression without shedding of the fleece during the experimental period was also seen. Results indicated that to obtain shedding of the fleece in 15-20 days after dosage, wool growth needs to be reduced below 20 per cent of its pre-treatment values and regrowth must be rapid.
Seasonal response of pasture to nitrogen fertilizer in the Mt. Lofty Ranges, South Australia
Authors: Elliot DE , Clarke AL
Published: March 2005

Ammonium nitrate (0 to 200 kg ha-1 N) was applied to new areas of pure grass (Lolium perenne and Dactylis glomerata) and of mixed clover and grass (Trifolium subterraneum, L. perenne and D. glomerata) at monthly intervals from autumn (April) to late winter (August.) at a site in the Mt. Lofty Ranges, South Australia, and the pasture harvested 1 and 2 months after each application. As fertilizer applications were delayed, pasture yield responded increasingly to nitrogen. When 100 kg ha-1 was applied to grass, yield increases measured 2 months later ranged from 2 to 25 kg D.M. kg-1 N for the May and August applications respectively. Mixed pasture was less responsive than grass to later applications, because nitrogen suppressed the increasingly vigorous clover growth ; with 100 kg ha-1 N, response 2 months after the August application was 16 kg D.M. kg-1 N. Applied nitrate and ammonium disappeared rapidly from the top 30 cm of soil. Only after the May and June dressings, when rainfall was light, did significant quantities persist for one month. Some of the nitrogen loss was from leaching. Herbage harvested after two months accounted for 17 to 48 per cent of nitrogen applied at 100 kg ha-1, the largest recovery following the July dressing. The relatively small responses to high rates of nitrogen in mid winter indicate that other factors, possibly light energy, limited the potential growth of the pasture. The results suggest that nitrogen could be used either to increase the supply of grazing in early spring or the production of hay in late spring, especially where pastures lack clover.
A study of phosphorus nutrition and water supply on the early growth and survival of buffel grass grown on a sandy red earth from south-west Queensland
Authors: Christie EK
Published: March 2005

The influence of phosphorus application on the growth and drought survival of buffel grass on a sandy red earth in south west Queensland was studied in a series of pot experiments. An omission nutrient trial showed phosphorus was the principal nutrient limiting seedling growth, the severity of the deficiency increasing with time. A further pot experiment showed that at rates greater than 24 kg P ha-1 luxury consumption occurred. The critical phosphorus concentration for the plant was estimated to be 0.26 per cent. The available (0.01 NH2SO4 extractable) soil phosphorus concentration corresponding to this critical tissue concentration was 25 p.p.m. Beyond the 2-leaf seedling stage, the seedling depended increasingly on external phosphorus for growth. Under conditions of phosphorus deficiency, phosphorus absorption rates were insufficient to maintain tissue phosphorus at the concentrations necessary for healthy growth, and relative growth rates were low. In the presence of phosphorus, absorption and growth rates increased. Maturity of phosphorus deficient plants was characteristically delayed but with little yield loss. The addition of phosphorus increased seedling growth rate, root development and drought survival. The depth of root penetration is considered to be the major factor responsible for survival.
Nodulation of and nitrogen fixation by Lablab purpureus under field conditions
Authors: Herridge DF , Roughley RJ
Published: March 2005

The nodulation and growth of Lablab purpureus was studied at three sites on the far north coast of New South Wales. These sites were chosen to provide low, medium and high competition by naturalised rhizobia for the seed-borne inocula. The effect of seedbed preparation was studied at the low competition site. Maximum yield occurred with clean cultivation although response to inoculation was best in a rough seedbed or when sod sown. Additional lime improved legume growth when it was dependent on symbiotic nitrogen but had no effect with a clean seedbed. Effective strains CB1091 and CB1406 established poorly at the high and low competition sites respectively. Strain CB1024 established well at all sites and with the three different methods of seedbed preparation.
Control of wheat leaf rust with 4-n-butyl-1,2,4-triazole
Authors: Rees RG , Platz GJ
Published: March 2005

The control of wheat leaf rust (Puccinia recondita tritici) by seed or foliar applications of 4-n-butyl-l,2,4-triazole (RH-124) has been examined in field experiments over three years at Gatton, Queensland. Single foliar sprays of RH-124 at rates as low as 100 g a.i, ha-1 have given excellent control of leaf rust. One such spray resulted in a yield increase of 30 per cent. A spray at 400 g a.i. ha-1 increased yield by 46 per cent compared with an increase of 61 per cent in the rust-free reference. Applications around the early boot stage of crop development were the most effective. Treatment of seed with RH-124 resulted in some control of leaf rust in one season with an associated yield increase of 22 per cent. Although RH-124 appears promising, additional studies are required before use of the fungicide on commercial wheat crops would be accepted.
A study on pollination of oilseed rape (Brassica campestris)
Authors: Langridge DF , Goodman RD
Published: March 2005

In a trial on an Oilseed Rape (Brassica campestris) crop grown on dry land in north-eastern Victoria, plots to which bees and larger insects had access produced 58 per cent more seeds per plant and 46 per cent greater weight of seed per plant than plots from which these insects had been excluded. The weight of 1000 seeds was significantly greater in the enclosed plots than in the open ones, but oil content of seed and germination did not differ significantly. Although hoverflies appear to play some role in pollination of rape we consider the honeybee the more efficient pollinator. Oilseed rape provides pollen and nectar for bees although no useable surplus of the latter was produced. Bee colonies increased brood rearing and colony population.
Effects of feeding varying levels of protein and phosphorus in relation to bone disorders in cattle
Authors: Siebert BD , Newman DMR , Hart B , Michell GL
Published: March 2005

Steers were fed low or high protein diets with varying levels of phosphorus. Two steers on the low protein diet developed a disorder which clinically resembled osteomalacia after 21 weeks of experimental feeding, and other animals on the same diet showed varying degrees of lameness. The total fresh weight, total mineral content, and the calcium and phosphorus levels of the metacarpal bones were significantly lower in the low protein group. Total fresh weight, total ash content of the rib bones was also lower although there were no differences between groups in the calcium and phosphorus content of rib bones. There were significant differences between treatment groups in blood levels of calcium, phosphorus and protein. The carcase weight of high protein animals was significantly greater than that of the low protein animals. Phosphorus level in the diet had little effect on any tissue measurement. The results showed that a bone disorder could develop in animals fed adequate phosphorus but inadequate protein. The implications of the experiment are considered in relation to the levels of protein and phosphorus in pasture throughout northern Australia.
Effects of mating behaviour and ram libido on the fertility of young ewes
Authors: Cahill LP , Blockey MAde B , Parr RA
Published: March 2005

Two groups of 92 and 93, 2 1/2-year-old maiden Merino ewes were each mated to a team of two, 13-year-old Corriedale rams. Both rams of each ram team were either of high or low libido and mating dexterity as determined by a series of pen libido tests. Continuous observations of mating behaviour were carried out on each group for 9.5 days and at 4-5 weeks post coitum (p.c.) the pregnancy rate was determined by laparotomy and hysterotomy. Although the ram pairs differed in libido in the pen tests, under the conditions of paddock mating there was found to be no significant difference between the two mating groups in the total number of mounts and services, the proportion of ewes detected in oestrus, the proportion of ewes pregnant, or the mean duration of oestrus. The duration of oestrus was shown to be dependent on the time of day at which the ewe was first detected in oestrus. Some ewes, although probably in oestrus, were not detected by the ram during periods of little mating activity and therefore their subsequent duration of oestrus was significantly shorter. The pregnancy rate of ewes with a duration of oestrus of less than one hour was significantly lower than that of ewes with a longer duration of oestrus.
Provision of high nitrogen roughage to sheep as a supplement to low nitrogen roughage
Authors: Robards GE , Pearce GR
Published: March 2005

Three feeding experiments and a digestibility study are reported in which the effects of supplementing low nitrogen roughages with roughages of high nitrogen content were studied. In each feeding experiment the effect of varying the frequency of supplementation was examined. During the first experiment intake of lucerne hay was greater (P < 0.05) than the intake of oaten hay and higher wool growth rates and liveweight changes were recorded. When the oaten and lucerne hays were alternated at intervals of one, two, three or four days, the average intake and rate of liveweight change was intermediate between the two previous levels, but the rate of wool production was similar to when lucerne hay was offered alone. There were no differences in total intake, clean wool production or liveweight change due to the frequency with which the two rations were alternated. The second experiment involved the feeding of a fixed quantity of lucerne hay with a. five times as much oaten hay or b. ad libitum oaten hay. The lucerne hay was given daily and every second, fourth and eighth days, and there was an unsupplemented control group. During the restricted feeding period frequent supplementation resulted in higher liveweight gain but there was no effect on wool growth. When oaten hay was provided ad libitum the poor response to supplementation and the large variation in intake within groups resulted in no significant differences in wool production or liveweight change between groups. The results of the third experiment indicate that the digestibility or degree of lignification of the basal ration affects the likelihood of a response to supplementation. It was shown that frequent supplementation of pasture hay resulted in higher intake, liveweight and wool production. On the other hand, substitute feeding with little change in animal production occurred when lucerne hay was offered to similar sheep consuming a basal ration of oaten hay which had a higher level of fibre and a lower in vitro digestibility than the pasture hay.
Relationship of wool production to stocking rate in Victoria
Authors: Jardine R , O'Brien S , Frew MV
Published: March 2005

Data from 14 stocking rate experiments, conducted over the period 1964-72, are used to derive a general relationship between wool production (W, kg sheep-1) and stocking rate (R, sheep ha-1), for the wool-growing areas of Victoria. This relationship is: W = (2.10 + 1.11P - 0.0045 C2) - (0.16 + 0.026 P - 0.00054 C2). R, where P ('productivity', kg sheep-1) and C ('carrying capacity', sheep ha-1) characterise any particular locality in a given year. The relationship is shown to be in accord with a simple theoretical model. In addition, some comparative ewe-wether relationships are presented.
Use of whale meal and whale solubles as dietary protein for growing pigs and their effects on the accumulation of mercury in tissues
Authors: Taverner MR
Published: March 2005

The effects of supplementing the protein from wheat in diets for growing pigs with either whale meal, whale solubles, fish meal, meat and bone meal or with combinations of whale meal or whale solubles with fish meal or meat and bone meal, were studied in two experiments. The mercury concentration in the muscle and liver of pigs fed the whale products was also studied. Pigs fed diets containing whale solubles as the only protein concentrate, grew more slowly, required more food per unit of liveweight gain and tended to have less lean in their hams than pigs fed diets containing concentrate protein from whale meal and/or fish meal, whale meal and meat and bone meal, or whale solubles and fish meal. The differences in pig performance between diets containing whale meal or meat and bone meal were not significant. Whale meal and whale solubles contained 10.5 and 2.5 p.p.m. of mercury, respectively, and the concentration of mercury in the diet was correlated to the mercury concentration in the tissues of pigs fed the diet. The muscle and liver of pigs fed with protein from whale meal had higher concentrations of mercury than those of pigs fed diets with equal amounts of protein from whale solubles. All the pigs fed whale products in this experiment had a concentration of mercury in their tissues greater than the health standard for human feedstuffs.
Yield performance of tall fescue (Festuca arundinacea) populations on the Northern Tableland of New South Wales
Authors: Schiller JMA , Lazenby A
Published: March 2005

Nine populations of Festuca arundinacea were grown in monoculture in two field trials on a black earth soil at Armidale, New South Wales during the period late 1967 to early 1970. There were four cutting treatments (at 2, 4, 8 and 16 week intervals) in both experiments and in trial 2 half the plots were irrigated. Seasonal and total herbage production were determined for two periods, each of forty-eight weeks duration, and tillering patterns were studied in trial 2. Differences were demonstrated in the seasonal and total production of the populations. Those selected from temperate environments were higher yielding in spring, summer and autumn and produced more total dry matter during the year than did those from the Mediterranean region ; however, in both experiments these latter yielded some 10 kg ha-1 day-1 more than the temperate fescues during the second winter. One cultivar-Goar's fescue-performed in a manner intermediate between the temperate and Mediterranean populations. Total dry matter yields were reduced when the cutting interval was decreased; in contrast, tiller numbers increased with frequency of cutting. The results suggest considerable potential value of Mediterranean fescues for winter pasture production on the Northern Tablelands of New South Wales.
Studies on the fruit thinning effect of N.A.A. and some carbamates on Jonathan and Delicious apples
Authors: Veinbrants N
Published: March 2005

In a series of experiments in Victoria a single spray of the fungicide thiram applied shortly after full bloom reduced fruit density highly significantly on Jonathan and Delicious apples, but resulted in insufficient thinning. The fungicide Dithane M-45 caused mild thinning and the fungicide Dikar had no effect on fruit set when applied during post-bloom period on Jonathan apples. Applications of the insecticide carbamult applied 16, 23 and 32 days after full bloom reduced fruit density highly significantly and to about the extent as N.A.A. applied 16 days after full bloom on Jonathan apples. Carbamult caused the same degree of thinning irrespective of time of application. N.A.A. and carbamult resulted in adequate fruit thinning.
Liveweight change, grazing time of steers and effect of pasture height on liveweight change following periods of hand feeding
Authors: Bailey PJ , Bishop AH
Published: March 2005

In two separate experiments, steers that had been fed hay in a feedlot lost weight during their first week at pasture whereas similar animals that grazed pasture throughout at least maintained liveweight. There was no difference in the grazing time per head of animals previously lot fed and those accustomed to grazing but steers previously from feedlots grazed longer per unit of metabolic liveweight. Length of pasture available for grazing following the feedlot phase was important. Differences in liveweight change between steers previously from a feedlot and those from pasture were less when animals grazed a tall rather than a short pasture. The reduction in loss was not significant.
Effect of supplements of molasses and urea on intake and digestibility of native pasture hay by steers
Authors: Ernst AJ , Limpus JF , O'Rourke PK
Published: March 2005

Ten steers (five Shorthorns and five Brahman crossbreds) were individually housed in digestibility crates and fed low quality native pasture hay (0.47 % N) with the following supplements- 1. nil ; 2. molasses ; 3. urea ; 4. urea-molasses ; 5. urea-molasses. The hay was fed ad libitum except in treatment 5 where it was fed at the same level of roughage intake as in treatment 2. Intake and digestibility were recorded. Treatments 2, 3 and 4 had roughage dry matter intakes 27.8 %, 14.6 % and 65.4 % respectively greater than the hay alone group. There was no significant effect of treatment compared with the control group on the apparent digestibility of dry matter or organic matter, but the apparent digestibility of crude protein was significantly improved by a supplement containing urea. There was no effect of breed on apparent digestibility of dry matter, organic matter or crude protein but Brahman crossbreds consumed 20.0 % more dry matter than Shorthorns after intakes had been corrected for metabolic size.
Relationships between condition score and carcass composition of pregnant Merino sheep
Authors: Yates WJ , Gleeson AR
Published: March 2005

Body condition scores of approximately 400 Merino ewes and the carcase composition of a sub-sample of ewes were determined by inexperienced operators at the tenth and twentieth weeks of pregnancy. Although the repeatability of estimating condition scores was low on both a within and between operator basis, subjectively assessed condition scores, when averaged for three operators, were positively correlated with the per cent of fat plus muscle in the carcase at both the tenth and twentieth weeks of pregnancy. Ewe liveweight was positively correlated with the per cent fat plus muscle in the carcase at the tenth but not at the twentieth week of pregnancy.
In vitro digestion of mixtures of grain and hay
Authors: Clark J
Published: March 2005

The digestibilities of the dry matter (DDM) of 16 herbages and 22 mixtures of grain and hay of known in vivo digestibility were determined by a two-stage in vitro technique, with inocula obtained from sheep fed either hay or a diet of 70 per cent barley and 30 per cent hay; both diets contained 12 per cent crude protein. The in vitro digestions were conducted with or without the addition of ammonium sulphate. The correlations between in vivo and in vitro digestibilities were higher for the herbages and the mixtures with inoculum from sheep fed hay, than with that from sheep fed barley and hay. Adding ammonium sulphate to either inoculum lowered the in vivo-in vitro correlation for the mixtures containing grain but improved the correlation for the herbage samples. The variability between replicate in vitro determinations was not reduced by adding ammonium sulphate to the inoculum from sheep fed hay but was increased for the inoculum from sheep fed a mixture of barley and hay.
Effect of defoliation frequency on growth and survival of four accessions of Psoralea eriantha
Authors: Gutteridge RC , Whiteman PC
Published: March 2005

Four accessions of the semi-arid shrub legume Psoralea eriantha were evaluated under three six and nine week cutting regimes for 72 weeks in pots in the glasshouse. Total yield increased in all accessions with increasing intervals between cutting. Yield in the three week cutting interval was only 36 per cent of the yield in the nine week cutting interval. The one erect accession, though giving the highest average yield, also suffered the highest mortality under the frequent defoliation. The other accessions suffered little mortality. Defoliation frequency affected root and stubble weights and these were closely correlated with total dry matter yields. Frequent defoliation also markedly reduced the number of primary and secondary shoots. It is suggested that survival under grazing may be more important than a higher yielding ability.
Nitrogen response of pasture grasses on duplex soils formed from granite in southern Queensland
Authors: Henzell EF , Peake DCI , 't Mannetje L , Stirk GB
Published: March 2005

The response to fertilizer N of native pasture containing black spear grass (Heteropogon contortus) and of buffel grass (Cenchrus ciliaris cv. Biloela) was measured on granitic soils at the Narayen Research Station, in southern Queensland. Experiments were carried out in grazed and ungrazed areas. In 1968-69, which was as dry as any year on record for this district, neither pasture responded to N; in wetter years both did, the native pasture giving a lower yield than the sown buffel grass pasture. Grazed areas that received 168 kg N ha-1 year-1 as urea did not respond to further additions. Analysis of buffel grass yields over intervals of 8 to 16 weeks during the growing season indicated that 1. there was no growth or response to N unless the rainfall exceeded about 30 mm, 2. above 30 mm the response to near-optimum rates of N increased with rainfall, 3. buffel grass grown with such rates of N produced more than four times as much DM per unit rainfall as buffel grass without added N when 100 mm of rain fell. Examination of rainfall records suggested that there is a high probability of worthwhile responses to N on these soils at Narayen.Spear grass and other native grass plants were killed by high rates of N during the first, dry season. The results of a pot trial with Biloela buffel grass and a late flowering strain of spear grass showed that N increased drought damage in both grasses but spear grass was more susceptible than buffel grass.
Seed dispersal and germination in Romulea rosea (onion grass)
Authors: Eddy JL , Smith DF
Published: March 2005

The role of sheep in the dispersal of seed of Romulea rosea was examined. It was found that the grazing animals ingested large numbers of seeds, and that although germination of defaecated seed was not high, each sheep dispersed more than 500 viable seeds per day. Under laboratory conditions sheep varied greatly in the rate of passage of seed, but germinability was not greatly reduced, compared with the original sample. Germination of samples of seed was studied on a thermogradient plate. Relative to some other components of pasture, germination was slow, and it was also much more reduced by temperatures above 16.5�C. These features, and perennation through corms, assist Romulea rosea in persisting in areas of variable summer rainfall.
Control of the weevil (Amnemus quadrituberculatus) in tropical legume pastures with dieldrin and heptachlor pre-sowing soil treatments
Authors: Rand JR , Braithwaite BM
Published: March 2005

Three experiments on chocolate alluvium, chocolate basaltic, and prairie meadow soils, respectively, tested the long term effectiveness of dieldrin and heptachlor pre-sowing treatments in controlling Amnemus quadrituberculatus (amnemus weevil) in tropical legume pastures. The legume species used were Desmodium uncinatum, D. intortum, Glycine wightii and Macroptilium atropurpureum. Both chemicals at rates from 0.56-2.24 kg ha-1 gave high levels of control of the weevil for two years after pasture establishment. Control declined in the third and subsequent years, but in all experiments insecticide treated plots retained the legume components longer than did untreated plots. Heptachlor at 1.12 kg ha-1 proved the best treatment but a general decline in legume density was observed in all experiments.
Screening rapeseed (B. napus) for low glucosinolate levels
Authors: Rayner CJ , Sang JP , Buzza CG
Published: March 2005

As part of a rapeseed breeding programme crosses were made between the low glucosinolate cultivar Bronowski and high glucosinolate cultivars Oro, Zephyr, Argentine, Chisaya and Norin 16. The 2887 F2 lines resulting from these crosses were initially screened for low glucosinolate character by the glukatest. Lines passing this test were examined in more detail using quantitative chemical techniques. The efficiency of the glukatest as an initial screening technique was demonstrated by the fact that it eliminated the large majority of high glucosinolate lines. L-5-vinyl-2-oxazolidinethione (OZT) was isolated from rapeseed and purified by a modified method using preparative thin layer chromatography. This method is described in detail.
The effects of dexamethasone TMA when used to synchronize parturition in monozygous twin dairy cows
Authors: Thomas GW
Published: March 2005

Parturition was induced in one member from each of eight sets of monozygous twin dairy cows by intramuscular injection of 20 mg Dexamethasone trimethylacetate. The resulting gestation lengths were less (P < 0.01) than those of the untreated twin counterparts. The actual 'within' twin calving spread was reduced to nil to 32 days (mean � S.D. 9 � 12 days) from an expected range of 22 to 53 days (mean � S.D. 38 � 12 days). The drug had a variable latent period (time from injection to parturition) and had no apparent effect upon the ensuing lactation yield (P > 0.05) or the subsequent return to postpartum oestrus (P > 0.05). The induced calves had lighter birth weights (P <: 0.01) and a higher mortality (6/8) than calves-from untreated cows (no deaths). There was a significant (P < 0.01) positive correlation (r = 0.846) between gestation length and birth weight of the calf.
Effect of time of joining and rate of stocking on the production of Corriedale ewes in southern Victoria. 4. Production of ewes born in July and September and effect of inclusion of Phalaris tuberosa in annual pasture
Authors: Kenney PA
Published: March 2005

The production of two groups of 56 ewes born either in the month of July or September in 1968,1969 or 1970 (a total of 336 ewes) was compared until November 1972. From weaning (1 2 weeks) to approximately 15 months of age the ewes were grazed on two types of pasture (with and without Phalaris tuberosa) at two rates of stocking (8 and 11 ewes ha -1) and thereafter ewes born in the same year grazed common pasture. Ewes lambed in August, the first lambing being at two years of age. Throughout the experiment ewes born in July remained heavier and produced heavier fleeces and heavier lambs than ewes born in September. In the first lambing (maiden ewes only) 20 per cent more lambs were weaned from ewes born in July than from ewes born in September but at later lambings differences in reproductive performance were small. Liveweight gains of ewes grazing pastures containing phalaris were 1 to 2 kg greater between November and February than those grazing pasture without phalaris. At their first lambing, ewes that had been grazing phalaris at the rate of 8 ewes ha-1 produced fewer lambs than the corresponding group grazing pasture without phalaris. Losses in production due to lambing ewes in July rather than September as previously reported are unlikely to be offset by production differences of their offspring.
Effects of cage population and stocking density on the performance of layers in Queensland
Authors: Connor JK , Burton HW
Published: March 2005

Three commercial egg production strains, a White Leghorn and two White Leghorn x Australorp, were used in two experiments which examined the effects of cage size and number of birds per cage on production characteristics. Nine cage housing systems varying from a 23 cm frontage single bird cage to a 61 cm frontage cage housing seven birds were compared. The efficacy of debeaking again at 12 or 20 weeks of age following routine debeaking at five days of age as a cannibalism control measure in a comparison of five housing systems was examined in another two experiments. Further experiments examined the practice of housing birds according to body weight in either one, two or three bird cage populations. Increasing bird numbers per cage or stocking density had little effect on egg weight, feed consumption or liveweight gain but decreased egg production and increased mortality in experiments where cannibalism was a significant cause of death. Hen housed egg production was an accurate measure of bird performance for comparison of housing systems. In experiments where additional debeaking was carried out the incidence of cannibalism was insignificant and debeaking at 12 or 20 weeks had no detrimental effect on bird performance. No strain x cage housing system interactions were observed and no improvement in performance resulted from housing birds in multiple bird cages according to liveweight.
The growth of three tropical pasture grasses on the mid-north coast of New South Wales
Authors: Kemp DR
Published: March 2005

The yields and seasonal growth curves of kikuyu grass, (Pennisetum clandestinum) setaria, (Setaria anceps cv. Kazungula) and broadleaf paspalum (Paspalum wettsteinii), were determined over a three year period at Taree (lat. 32�s) New South Wales with or without irrigation and under nil, 170 or 680 kg N ha-1 yr-1 (nil, low and high N). Annual forage yields averaged 1300, 51 00 and 13,000 kg DM ha-1 at nil, low and high N respectively. Kikuyu grass yields were significantly less than setaria or broadleaf, especially at low N. Both the apparent recovery of nitrogen and the efficiency of dry matter production by kikuyu grass were less than the other grasses. Yields from the irrigated plots were similar to the dryland plots due largely to a generally favourable rainfall pattern. During short dry periods the extra yield from irrigation was less than from the application of nitrogen. The patterns of seasonal growth were similar for each species at any one nitrogen rate and irrigation treatment. The growing season (>5 kg DM ha-1 day-1) without nitrogen, was only four to six months, commencing in late spring. This was increased to eight months at low N (October to May) and nine months (September to May) with high N. The mean period of high growth rates (>60 kg DM ha-1 day-1) over summer was nil at nil N, only six days at low N but increased to 154 days at high N. Winter growth was negligible.
Leaf water potentials of pasture plants in a semi-arid subtropical environment
Authors: Peake DCI , Stirk GD , Henzell EF
Published: March 2005

Leaf water potentials (�1) were measured on pasture plants at the Narayen Research Station in southern Queensland. The main findings were: 1. There were marked differences between species in the value of �1, measured during drought. Lucerne (Medicago sativa cv. Hunter River) and buffel grass (Cenchrus ciliaris cv. Biloela) usually showed a lower (i.e. more negative) �1 than Siratro (Macroptilium atropurpureum cv. Siratro), when they were grown together in a mixed pasture. Siratro seemed to possess a useful degree of drought avoidance. High drought resistance was observed in buffel grass; this was attributed to its tolerance of water stress. Green panic (Panicum maximum var. trichoglume cv. Petrie) was found to have as low a �1 as lucerne during drought when the two species were grown with Siratro in a mixed pasture. 2. The plants were under severe water stress before all the available water was removed from the deeper soil horizons. 3. �1 was lower in nitrogen-fertilized buffel grass or spear grass (Heteropogon contortus), than in the corresponding unfertilized controls. 4. The vapour-exchange and dye-marker densiometric methods gave different values for �1 in buffel grass, green panic and Siratro; the vapour exchange technique recorded lower, i.e, more negative figures than the other method when the plants were under severe water stress. The two methods gave similar values for lucerne. The relation between the values obtained for buffel grass by the two methods was affected by nitrogen fertilization. The reaction of sown pasture plants to drought at Narayen is discussed.
Studies on some neutral red duplex soils (Dr 2.12) in north-eastern Queensland. 3. Availability of phosphorus in the C-horizon
Authors: Probert ME
Published: March 2005

The C horizon phosphorus in neutral red duplex soils derived from granodiorite is shown by electron microprobe analysis to be present as coarse grains of apatite. Glasshouse experiments failed to show any contribution from this phosphorus to the nutrition of the test crops (Townsville stylo Stylosanthes humilis and green panic Panicum maximum). Since this phosphorus is soluble in 0.01 N H2SO4, this extractant grossly overestimated the available phosphorus status whereas extraction with 0.5 M NaHCO3 indicated the non-availability of the C horizon phosphorus in these soils.