bluuebunny/crossref_metadata_2025 huggingface dataset:
Response of burr burial in subterranean clover (Trifolium subterraneum) to defoliation
Authors: Walton GH
Published: March 2005

Four defoliation treatments before flowering were imposed on twelve genotypes from three subspecies of Trifolium subterraneum. The experiment was conducted on a sandy soil with irrigation supplementing the natural rainfall. The severest defoliation doubled the percentage and tripled the absolute yield of buried seed. Highly significant differences were found between the genotypes within subspecies, indicating that selection for subterranean clover pastures with a range of ability to bury burrs is possible. No differences in genotype or subspecies response to defoliation nor differences of absolute seed yields were obtained. It is suggested that sward density is very important when experiments evaluating subterranean clover genotypes include defoliation treatments of the swards.
Diagnostic leaf analysis for stone fruit. 6. Apricot
Authors: Leece DR , Ende Bvan den
Published: March 2005

Changes in the nutrient-element composition of leaves of 'Trevatt' apricot 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. Thus, leaf composition standards should be based on January- February samples and diagnostic sampling should be confined to this period where possible. Correction factors for adjusting the composition of early or late samples back to January 31 levels, were calculated from polynomials with time fitted to the leaf composition data. A survey of the leaf composition of well-managed 'Trevatt' apricot orchards was conducted each January from 1971 to 1973 in New South Wales and Victoria. Percentages of orchards classified as low to deficient (-), and high to excess (+) for various nutrients were as follows : New South Wales (averages of 1971 to 1973) N -41 ; P +37; K +49; Mg +56; Fe +1 9 ; Zn -18. Victoria (averages of 1972 and 1973) N -21 and +32; K +10; Fe -35; Mn +17; Zn -20.
Beef production from pasture and forage oats on the Northern Tablelands of New South Wales
Authors: Hennessy DW , Robinson GG
Published: March 2005

To overcome a winter-sp nes, New South Wales forage oats were sown into forty-five per cent of improved pasture (mainly Phalaris tuberosa and Trifolium repens) areas and the liveweight gains of weaner cattle grazing these areas from March to October were compared with those grazing pasture only. Three methods for managing the grazing of the forage oats were compared in 1971, and in 1972 the effect of an oat grain supplement on liveweight gain of cattle grazing either pasture only or pasture and forage oats was measured. Weaners did not reach 270 kg by October, the objective mean liveweight, in any of the treatments or years. Neither did forage oats significantly increase beef production from pasture, but when properly managed did reduce the need for hay supplements to maintain weaner liveweight during winter. Although the stocking rate of 2.82 weaners ha-1 from March to October was apparently too high in 1971 to allow adequate liveweight gains, the forage oats and pasture were best utilized by allowing weaners to graze freely between paddocks. Oat grain supplements in 1972 did improve weaners' liveweights (at intakes of 1 .O-2.0 per cent liveweight) but reduced the relative economic return from either the pasture or pasture and forage oat areas. We concluded from the study that forage oats sown into improved pasture areas did not increase feed availability in the latter part of the feed-gap nor reliably increase beef production from pasture at the stocking rate studied.
Effect of stocking rate, fodder conservation and grazing management on the performance of wether sheep in south-west Victoria. 1. Wool production
Authors: Bishop AH , Birrell HA
Published: March 2005

In a 4 x 4 x 3 factorial experiment lasting three years, the effects of stocking rate, fodder conservation and three grazing management systems (continuous, deferred and rotational) on the wool production of wethers grazing perennial pasture were assessed. The hay conserved on the plots was fed to the sheep in such a way that the quantities made and fed would balance over a period of years. At the highest rate of stocking some oats were fed in adverse seasons. Stocking rate had the major effect on wool production in all years. Improving wool production by fodder conservation was shown to depend on stocking rate, grazing management and the seasonal conditions. In some instances fodder conservation was shown to interact with stocking rate in a manner such that the maximum response tended to occur when smaller proportions of area were conserved as stocking rate increased. The implications of this interaction are discussed. Fodder conservation increased wool production in the continuous and rotationally grazed systems in all years, but did not in two of the three years with deferred grazing. The biggest increases in wool production due to fodder conservation occurred in the third year, the driest on record when a drought reserve was used. Wool production was also influenced by the grazing management. In alt-years there was a consistent interaction with stocking rate in which the highest wool production was produced in the rotational system at high stocking rates and in the deferred system at low stocking rates.
Influence of different maize genotypes and cytoplasms on resistance to Drechslera maydis race T on the north coast of New South Wales
Authors: Colless JM
Published: March 2005

Sixteen Australian and two United States maize (Zea mays) inbred genotypes, and six single and double-cross hybrids, were evaluated for reaction to natural infection by Drechslera maydis (race T) Zea (Maydis Leaf Blight) in the field at Grafton, New South Wales, in 1973. Each genotype was evaluated in Texas male-sterile (T) cytoplasm and normal (N) cytoplasm. All lines with T cytoplasm were susceptible to the disease, but those with N cytoplasm were resistant. However, the progress of the disease was significantly slower on inbred NNI 8 and, to a lesser extent, on inbred 25. Variation in degree of resistance among genotypes in N cytoplasm was also observed. Although D. maydis (race T) was virulent on plants with T cytoplasm, another form of male-sterile cytoplasm, designated C, did not predispose plants of one hybrid and two inbred genotypes to the disease. Comparisons were also made between each of six Australian inbred genotypes in T cytoplasm and their respective backcross recoveries having male-fertility restoring genes. The presence of these genes had no effect on plant reaction to D. maydis (race T) infection.
Effect of creep feeding oat grain to beef calves on their growth rate, carcase composition and post-weaning performance in a feedlot
Authors: Corah LR , Bishop AH
Published: March 2005

Autumn and spring born Hereford calves grazing together with their dams were offered a ration of oaten grain ad libitum in a creep enclosure to which only the calves had access from November to weaning. Similar groups received no oat ration. At weaning the heifers of each age were slaughtered and carcase characteristics were determined. The steers were placed in a feedlot and given a ration of hay and grain until they attained an unfasted weight of 340 kg. The creep fed calves maintained their earlier growth rates after taking the creep ration, whereas the growth rate of the unfed controls declined from this time. Time of birth, creep feeding and sex all affected liveweight gain to weaning. Creep feeding increased the carcase weight of the heifers and also affected dressing percentage, eye muscle area, fat thickness and chemical composition. Creep feeding prior to weaning did not influence the average daily weight gains or feed efficiency of steers subsequently fed a fattening ration in a feedlot but it greatly shortened the feeding period to attain the desired market weight. However, the reduction in feed required would be insufficient to compensate for the oats given during creep feeding. The economics of creep feeding will depend on the price of grain in relation to the value of weaned calves in slaughter condition.
Feeding steers high levels of oats and wheat: effects of substituting one grain for the other
Authors: Gartner RJW , O'Rourke PK
Published: March 2005

Hereford and Shorthorn steers were fed in yards for an initial period of 63 days, (including a 20 day change-over period) during which chaff and either wheat or oat grain were fed ; then for 5 days one grain was gradually substituted for the other; a final period of 64 or 71 days of feeding then followed. Two levels of grain were examined, 60 and 90 per cent, and similar percentages of an equal mixture of both grains were fed unchanged throughout the entire period. No digestive disturbances resulted from the substitution of the grains. In both the initial and final periods the steers receiving 90 per cent wheat had significantly higher liveweight gains than those on oats (1.36 v. 0.72 � SE 0.122 and 1.60 v. 0.84 � 0.079 kg per day). These gains were associated with an intake of wheat significantly higher than that of oats in the final period only (8.13 v. 5.88 �. 0.337 kg per day) and a lower (not significant) feed conversion of 5.31 v. 8.47 � 0.671. Results for an equal mixture of both grains were intermediate between those obtained with the single grain diets. There were no differences between treatments at the 60 per cent grain level. The dressing percentage of steers finishing the experiment on wheat (54.5 � 00.4) was significantly higher than of steers finishing on oats (51.9) or on a mixture of the grains (52.4).
Substitution of sugar for grain starch in the rations of laying hens
Authors: Beeton RJS , Cumming RB , McClymont GL
Published: March 2005

Five and a half month old commercial strain laying pullets were fed on four diets containing from zero to thirty per cent raw sugar for a total of eleven months. Laying cages and deep litter housing were used in a factorial design. All sugar levels had no effect on overall egg production, feed consumption conversion, weight gain and mortality. A tendency for the production of more 55 g eggs at the expense of 60 g eggs is apparent in the results. The results confirm those from overseas that laying pullets will maintain normal levels of production for sugar levels of up to 30 per cent of their laying rations.
Effects of nutrition in the growing period on the subsequent performance of crossbred layers
Authors: Lahore RM , Payne CG
Published: March 2005

Crossbred White Leghorn-Australorp pullets were reared from 5 weeks of age to point of lay on 8 nutritional treatments. These included : a. an ad libitum fed positive control, b. 2 physically restricted treatments in which energy intake was reduced by 25 and 40 per cent, c. 3 low lysine treatments (0.36 per cent dietary lysine) in which the arginine-lysine ratios were 1.4, 1.8 and 2.2 : 1, d. 2 diets which contained excessive levels of methionine and lysine respectively. In the laying phase 4 ad libitum nutrient treatments were applied factorially with the rearing treatments. All experimental rearing treatments improved overall conversion of feed into eggs by 3.6-6.6 per cent compared with the positive control rearing treatment. This improvement was despite the fact that both the physical restriction and the low lysine treatments delayed sexual maturity by 9.5-26.2 days. The 40 per cent physical restriction and the low lysine treatments resulted in smaller sized pullets at point of lay, which laid significantly heavier eggs. There were no differences in subsequent performance between pullets reared on the three low lysine diets of differing arginine content. The data indicated that smaller sized pullets resulting from controlled energy intake during rearing may respond more to elevated nutrient intakes during the laying phase compared with ad libitum reared pullets.
Heavy metal contents of soils and plants adjacent to the Hume Highway near Marulan, New South Wales
Authors: David DJ , Williams CH
Published: March 2005

HCL-extractable zinc, lead, cadmium and copper in soils as well as concentrations of these elements in bracken (Pteridium esculentum) were found to decrease along four leeward traverses at right angles to the Hume Highway near Marulan. Similar results were obtained for the above-ground portions of rye corn (Secale cereale) grown in a glasshouse on soils collected along one of these traverses. Zinc accession is similar to, but cadmium and lead accessions are considerably lower than, those observed by other workers in the United States probably owing in the case of cadmium to the use of purer zinc oxide in Australian tyre manufacture and in the case of lead to smaller cars and a smaller proportion of vehicles operating on leaded fuel. Zinc and cadmium analyses of Australian and foreign tyres confirmed the relative purity of the zinc oxide used in the manufacture of tyres in Australia. No serious health hazard appears to arise from heavy metal contamination of roadside soils and vegetation by vehicular traffic on the Hume Highway.
Studies on cattle with oesophageal fistulae: comparison of concentrations of mineral nutrients in feeds and associated boluses
Authors: Little DA
Published: March 2005

Eight forages were fed in small quantities to cattle with oesophageal fistulae. The feeds and boluses were analysed for Ca, Mg, S, Mn, Mo, Cu, Zn, and Ti. Bolus composition could be used to predict dietary levels of Ca, S, Cu, and Mg with reasonable precision (error <� 9 per cent), but feed concentrations of Mo and Mn could be predicted only with an error of �15 per cent. Levels of Zn in boluses could not be used to predict dietary levels, since bolus Zn greatly exceeded that of the feed. The presence of Zn in bovine saliva was demonstrated. Concentrations of Ti in feeds and boluses were in close agreement; measurement of Ti in boluses appears to provide a potentially useful method for the identification of those contaminated with soil during grazing studies.
Effects of topdressed superphosphate on the sheep and pasture production of dryland lucerne in central western New South Wales
Authors: Brownlee H , Scott BJ , Kearins RD , Bradley J
Published: March 2005

Merino ewes at 3.7, 4.9 and 6.2 ha-1 grazed dryland lucerne (Medicago sativa cv. Hunter River) topdressed annually with superphosphate at 0, 125 and 251 kg ha-1, from September 1969 until December 1972, in an experiment at Condobolin, New South Wales. Superphosphate increased ewe liveweights, total forage available and phosphorus content of the forage by a small amount but did not increase wool production per head. The Bray soil phosphorus test in the top 8 cm of the soil profile rose from 8 p.p.m. to 48 p.p.m., but most of the phosphorus was concentrated in the 0-4 cm layer, where we consider that dry conditions reduced its availability to the lucerne. As stocking rate increased, ewe liveweights and wool production per head decreased and the sheep required more handfeeding for survival. The treatment with the greatest gross margin was the lowest stocking rate with nil fertilizer.
Environmental effects on the short-term response of tropical grasses to nitrogen fertilizer
Authors: Murtagh GJ
Published: March 2005

The short term response of tropical grasses during spring to ammonium nitrate and urea fertilizers (1 12 kg N ha -1) was measured on kikuyu (Pennisetum clandestinum) at one site, and on setaria (Setaria anceps cv. Kazungula) at two sites. Fertilizers were applied at weekly intervals on 16 occasions at each site during the August-December period. Treatments were assessed in terms of the dry matter response (DMR) and apparent recovery of fertilizer nitrogen (NR), where DMR is the differences in dry matter yield of topdressed plots over the control and NR is the corresponding difference in nitrogen yield expressed as a percentage of the amount of nitrogen applied as fertilizer. These responses were measured at four, and sometimes at eight weeks, and were related to environmental variables by regression analysis. The DMR was more responsive than NR to changes in temperature. Both DMR and NR were very sensitive to changes in soil moisture potential, especially on wet soils, and to changes in effective rainfall (rainfall less run-off). If low temperature limited growth during the first four weeks after topdressing, both DMR and NR increased further when growth during 5-8 weeks extended into warmer periods. However, when moisture supply limited the response at four weeks, the NR remained depressed at eight weeks even with an improved moisture supply. Environmental factors influenced the response more than the type of nitrogen fertilizer and at four weeks, the respective overall DMR and NR from urea were 90 and 86 per cent of those from ammonium nitrate.
Behaviour of beef cattle in equatorial lowlands
Authors: Schottler JH , Efi P , Williams WT
Published: March 2005

A new method of transcribing visually-recorded behavioural data rapid computer processing ; it is applied to a total of 31 animals (bulls, cows and calves) in the Markham Valley, Papua New Guinea. There is no evidence of seasonal variation. Approximately one-third of grazing is carried out at night, so that night yarding is not indicated without further investigation. Total times spent in recorded activities are comparable with those for temperate climates. There is evidence for an effect of breed, in that animals with more than half-shorthorn ancestry show a marked reduction in mid-day grazing.
Lucerne persistence and the productivity of ewes and lambs grazed at two stocking rates within different management systems
Authors: Southwood OR , Robards GE
Published: March 2005

From 1967 to 1971 a grazing experiment was conducted at the Agricultural Research Station, Temora, New South Wales with Merino ewes and first cross spring lambs on lucerne pastures. Set stocking was compared with a number of rotational systems at twice replicated stocking rates of five and ten ewes ha-1. The rotational systems consisted of either five or seven paddocks each grazed to give a constant pasture recovery time of 36 days year round, or 36 days mid-summer to mid-winter and 24 days when lambs were present. Stocking rate was the only variable affecting ewe wool production and body weight. During the driest year the constant rotation was the best treatment, whereas in the wetter year ewes managed in a variable rotation grew most wool. The number of lambs born and their birth weight did not vary among treatments. Growth rate was slower at the higher stocking rate but the management treatments had no effect on lamb growth. Lucerne plant density decreased by half during the first three years of the experiment. Thereafter plant density was maintained in the rotationally grazed systems. Under continuous grazing at the high stocking rate no lucerne survived after four months but at the low stocking rate most remaining plants died after a spring drought in 1971.
Temperatures in wheat during radiation frost
Authors: Marcellos H , Single WV
Published: March 2005

Plant and air temperatures were measured during radiation frost within a crop of wheat (Triticum aestivum cv. Timgalen) grown in 1974 on the Liverpool Plains Field Station, Breeza, New South Wales. Observations were made at different heights within the canopy at several stages of crop development, and these were related to screen and grass minimum temperatures recorded in a meteorological enclosure adjacent to the crop. Coldest conditions were found near the surface of the crop where temperatures were as much as 2�C lower than those in middle regions of the canopy. The temperature just below the soil surface was between 4� and 6�C warmer than that of plant or air at 5 cm to 10 cm above its surface. Grass minimum temperature was linearly related to screen minimum and found to be 3�C lower. Either measurement was useful in estimating the lowest temperature within that canopy.
Effect of time of joining and rate of stocking on the production of Corriedale ewes in southern Victoria. 5. Ovulation rate and embryonic survival
Authors: Davis IF , Kenney PA , Cumming IA
Published: March 2005

In the final five months of an experiment which had lasted from November 1967 to June 1971 a study was made of the ovulation rate and embryonic survival in a flock of 540 five-year-old Corriedale ewes grazing annual pasture in southern Victoria. Ewes were stocked at 5, 7 1/2 or 10 ewes ha-1, and were joined with rams for six weeks beginning at either February 8 or April 19, 1971. A comparison with actual lambing data in 1970 was made. Ewes stocked at 5 ewes ha-1 had a higher ovulation rate and estimated lambing rate (based on embryos surviving to day 28) than those stocked at 7 1/2 or 10 ewes ha-1. Ovulation rate was higher for ewes of high liveweight than for ewes of low liveweight among those stocked at 7 1/2 and 10 ewes ha-' but not among those stocked at 5 ewes ha-1. Ewes joined in April had a higher ovulation rate and estimated lambing rate than ewes joined in February. There was no significant interaction between joining time and stocking rate on estimated lambing rate which was in contrast to the previous year 1970, when increased stocking rate reduced the number of lambs born per ewe from the February joining. Embryonic survival was greater among ewes joined in February and stocked at 7 1/2 ewes ha-1. There was no difference between stocking rates in embryonic survival among ewes joined in April. There was a trend for fewer twin ova to be lost when shed in April than in February.
Whole wheat grain feeding of Merino ewes. 4. Changes in hepatic vitamin A concentration
Authors: Reynolds JA , McManus WR , Robertson JA
Published: March 2005

In two experiments Merino breeding ewes were fed wheat in pens or small paddocks from joining to weaning. Three levels of wheat were examined in each experiment and at each wheat level one-half of the ewes received vitamin A, Injections of 1 million I.U. of vitamin A were given twice in the first experiment and four times in the second. Control groups of ewes were run at pasture or fed pasture hay. Ewes injected with vitamin A had higher hepatic concentrations of the vitamin than those unsupplemented. Wheat intakes, which ranged from 3.4-7.1 kg ewe-1 week-1, had no effect on either the rate of expenditure of hepatic vitamin A concentration or the extent of storage and absorption of the vitamin after dosing. Pregnancy and lactation did not significantly increase changes in hepatic vitamin A concentration. The relationship between hepatic vitamin A concentration and time was curvilinear in ewes fed wheat without vitamin A. The rate of loss was not different between experiments and amounted to 6.03 per cent per week.
Nitrogen accretion and other soil changes in Tindall clay loam under Townsville stylo/grass pastures
Authors: Myers RJK
Published: March 2005

Soil changes after 3-15 years of fertilized leguminous pastures on Tindall clay loam soil at Katherine, N.T. were studied by comparison of leguminous pasture soils with their native counterparts. Soil organic carbon, total nitrogen, C/N ratio and pH were unchanged by the presence of Townsville stylo (Stylosanthes humilis). Available phosphorus (bicarbonate extraction) was significantly higher under legume pasture, reflecting its fertilizer history, but there was no pattern of increase with time, nor with quantity of fertilizer. Available nitrogen (boiling water extraction) was higher under legume pasture, and both the absolute value under legume pasture and the change in amount were correlated significantly with the age of the pasture. Available nitrogen after three years of legume pasture was equal to that under unimproved pasture, suggesting that gains in this period merely balanced losses during clearing and establishment.
Whole wheat grain feeding of pregnant and lactating ewes and their lambs. 2. Lamb productivity from whole wheat diets with varying levels of sodium chloride and elemental sulphur supplements
Authors: Saville DG , Nicholls PJ , McManus WR
Published: March 2005

Lambs born to ewes fed whole wheat grain were raised and fattened on whole wheat supplemented with varying levels of sodium chloride or elemental sulphur. Liveweights, wheat intakes, feed conversions and carcase weights were measured. Lamb birth weights increased with increasing quantities of energy, and of sodium chloride at high sulphur levels, offered to the ewe during late pregnancy. A weaning weight response to sodium chloride supplementation at high sulphur levels (P < 0.10) was substantially reduced when weaning weight was adjusted for ewe milk production. Lambs were successfully weaned at seven weeks of age to a diet of whole wheat grain. Their subsequent slaughter weights and carcase weights increased with sodium chloride supplementation up to levels of about 1.2 to 1.4 per cent. Little change occurred in the sodium chloride response when slaughter weight was adjusted for weaning weight. The importance of these results in relation to the mineral requirements of lambs fed whole wheat grain is discussed.
Seed production of Stylosanthes guyanensis. 2. The consequences of defoliation
Authors: Loch DS , Hopkinson JM , English BH
Published: March 2005

The consequences of defoliation on seed production of stylo (Stylosanthes guyanensis) were examined in field experiments at Walkamin in north Queensland. The practical aim of defoliation is to present a level uncompacted crop canopy to the harvester without a reduction in the quantity of seed carried at harvest ripeness. It was concluded that the latest date at which defoliation is reasonably certain to achieve its objectives is about four weeks before first flower initiation. In north Queensland, this means late February for cvv. Cook and Endeavour and early April for cv. Schofield. The results suggest that development of the population of individual shoots must be synchronized to produce the highest peaks of standing seed; that this is best achieved by ensuring that a closed crop canopy with a ceiling shoot population exists at the time of first flower initiation; and that poorly synchronized shoot development is a consequence of defoliating too late and a cause of reduced seed production.
Predictions of likely theft by ants of oversown seed for the Northern Tablelands of New South Wales
Authors: Johns GG , Greenup LR
Published: March 2005

At Armidale, New South Wales, ant theft rates of pasture seeds at sites that had been topdressed with 10 kg ha-1 seed immediately before a four day observation period averaged 27 per cent less than on areas where no such application was made. Strong regression relationships were established between theft rates of the various seed types and both air and soil temperatures, but no relationship was found between either relative humidity or soil water availability and theft rate. High theft rates recorded in the first 24 hours after seed placement were not sustained over longer periods of time. A relationship between the decline in theft rate and the quantity of seed available was established. A series of predictions have been made of the proportion of seed likely to remain during fine weather following oversowing in the Armidale environment. These predictions incorporate seed type, time since sowing and prevailing air temperatures. It is predicted that during winter 70 to 80 per cent of bare seed and 90 to 97 per cent of coated seed could remain 30 days after oversowing. During summer the comparable figures are 7 to 30 per cent and 22 to 36 per cent respectively.
Assessment of reproductive wastage in sheep. 1. Fertilization failure and early embryonic survival
Authors: Restall BJ , Brown GH , Blockey MdeB , Cahill L , Kearins R
Published: March 2005

The measurement of fertilization rate and embryonic survival in ewe flocks has been examined from both a theoretical and practical viewpoint. An hypothesis of independence (of survival) for ova or zygotes in multiple ovulating ewes was tested in data obtained from four adult and four maiden ewe flocks mated during the autumn, both crossbred and Merino ewes being examined. Only the adult ewe flocks, with reasonable numbers of multiple ovulating ewes, provided adequate information to test the hypothesis. The data for fertilization rate showed significant deviation from the hypothesised binomial distribution (independence hypothesis). Fertilization appeared to be 'all or none'; that is, irrespective of the number of eggs present in the ewe, they were either all fertilized or all not fertilized. An 'all or none' model for fertilization is described and parameter estimates given. Data for embryonic survival in single and twin ovulating ewes were in agreement with the binomial distribution and the independence hypothesis was accepted. Methods are described for using the 'all or none' and the 'independence' models to obtain estimates of fertilization rate and embryonic survival in investigations of ewe infertility.
Synchronization of oestrus and subsequent fertility in cattle, using the prostaglandin F2α analogue, ICI 80996 (cloprostenol)
Authors: Hearnshaw H
Published: March 2005

The prostaglandin analogue, ICI 80996 (cloprostenol), was administered subcutaneously to synchronize oestrus in cattle. One injection, or two injections 12 days apart, of 400 pg gave optimal results (78 and 72 per cent synchronized respectively) for the Hereford cross heifers used. Heifers treated with cloprostenol from days one to five of the cycle, did not respond to the first injection, but did so to a second injection given 12 days later. A greater percentage of heifers, treated in the mid or late luteal phase of the cycle, exhibited oestrus after the first injection of cloprostenol than after the second injection. The percentage of these heifers showing induced oestrus varied from 44 to 100 per cent. There was a peak in the incidence of oestrus between 49 and 72 hours after injection but the distribution ranged from 24 to 120 hours. Peripheral blood progesterone concentrations, palpation of the ovaries and subsequent cycle lengths, indicated that the cloprostenol had no adverse effects in the majority of heifers. However, about 30 per cent of the heifers that responded to an initial injection of cloprostenol given in the mid luteal phase of the cycle failed to respond to a second injection. Some of these heifers had abnormal progesterone profiles and subsequent reproductive patterns. Fertility, following one or two subcutaneous injections of cloprostenol and artificial insemination at the set times of 72 and 96 hours, was 30 and 46 per cent respectively. However, if only heifers inseminated at the optimum time were considered, fertility at pregnancy diagnosis (73 and 65 per cent) and calving (53 and 57 per cent) was acceptable.
Use of oat, lupin and field pea stubbles by grazing sheep
Authors: Mulholland JG , Coombe JB , Dann PR
Published: March 2005

Crops of oats (Avena sativa), lupins (Lupinus angustifolius) and field peas (Pisum arvense) harvested in January 1974 yielded respectively 1748, 1431 and 121 4 kg DM grain and 6880, 351 0 and 3350 kg DM stubble ha-1. After harvest the stubbles were grazed for 14 weeks with crossbred ewes and wethers at 11.25 and 22.5 ha-1. Straw from each stubble was of uniformly low digestibility (30 per cent), but legume straw was consistently higher in N than oat straw (1.4 vs. 0.77 per cent N). A strong preference by sheep for green material resulted in most of the crop residue remaining at the end of the experiment. There was a small liveweight gain at the tower stocking rate and a weight loss at the higher stocking rate (P < 0.01). Sheep grazing pea stubble at the lower stocking rate gained 3 kg more than those on oat stubble but the differences were not significant (P< 0.05)
Ovine congenital goitre associated with minimal thyroid enlargement
Authors: King CF
Published: March 2005

An outbreak of congenital goitre associated with minimal thyroid enlargement resulted in a high level of lamb mortality (36.1 per cent) in a flock in northern Tasmania. Palpation was shown to be a valid means of assessing thyroid gland size and a significant linear relationship between thyroid size and lamb mortality was demonstrated (P < 0.01). Although the overall difference in mortality rate between normal and goitrous lambs was significant this was confined to the middle of the birth weight range; at either end of the range the normal and goitrous lambs experienced similar levels of mortality. Goitrous lambs died earlier and had less chance of walking or metabolising their fat reserves than their normal counterparts. There was no effect of sex or type of birth (single or multiple) on incidence of goitre. In most of the goitrous lambs that survived, thyroid size had regressed to normal in about six weeks.
Effects of dietary energy concentration on production of broiler chickens
Authors: Farrell DJ , Hardaker JB , Greig ID , Cumming RB
Published: March 2005

Eight least-cost diets with a determined range of metabolizable energy (ME) concentrations from 9.3 to 14.3 MJ kg-1 were formulated. Each diet was offered for about 12 weeks to two pens of about 100 broilers of each sex. Observations on feed consumption, liveweight and mortality were made weekly for each pen. Dressing percentages were recorded for samples of ten birds from each pen at two different Iiveweights. As ME concentration of the diets increased, birds grew faster and required less food, in terms of both total weight and total energy, to reach specified liveweights, although these effects were not marked when the dietary ME concentration was above 13.5 MJ kg-1. Feed conversion was less efficient at the same ME concentration when birds of each sex were taken to higher liveweights. Dressing percentage increased with increases in dietary ME concentration for males, but for females it tended to decline at the highest energy concentrations. Mortality was the same (2 per cent) on all diets.
The digestibility of summer growing grasses estimated by three techniques
Authors: Hall DG , Hennessy DW
Published: March 2005

Ten ruminally fistulated steers were used in pen trials at Grafton, New South Wales, to estimate the digestibility (OMD) of five summer growing grasses from January to March. A nylon bag technique was used to estimate the OMD on cut and oesophageal extrusa samples of the grasses, and the accuracy of the technique was assessed. These estimates were compared with those from the in vitro technique. The mean OMD's of the grasses were generally less than 65 per cent. The nylon bag and in vitro techniques estimated the OMD with low precision. It was concluded that the techniques used did not accurately estimate the OMD of the grasses examined.
Alternative insecticides for the control of the pasture cockchafer (Aphodius tasmaniae Hope) in pasture
Authors: Allen PG
Published: March 2005

A field trial was conducted to compare methidathion (400 g ha-1 a.i.), endosulfan (500 g and 350 g ha-1 a.i.), phosmet (400 g ha-1 a.i.) and chlorfenvinphos (400 g ha-1 a.i.) with lindane (300 g ha-1 a.i.) for the control of pasture cockchafer larvae in pasture. Methidathion and both rates of endosulfan provided better or similar levels of control of larvae compared with lindane and were better than phosmet and chlorfenvinphos. Endosulfan (350 g ha-1 a.i.) and methidathion (400 g ha-1 a.i.) are recommended for control of pasture cockchafer larvae in South Australia.
The effect of foliar and soil applied molybdenum treatments on the molybdenum concentration of maize grain
Authors: Weir RG , Nagle RK , Noonan JB , Towner AGW
Published: March 2005

Soil and foliar treatments to raise the concentration of molybdenum in maize grain were compared. Both methods raised molybdenum concentrations in the grain and leaves, but the foliar sprays were more effective. Spraying when the maize plants were 80 cm tall increased the molybdenum concentration in the seed more than earlier spraying when the plants were only 30 cm tall. None of the treatments affected grain yield or the nitrogen concentration in the grain or leaves. Foliar sprays should allow a reduction in the rates of molybdenum now needed to maintain adequate levels in certified hybrid maize seed.
The utilization by beef cattle of sugarcane supplemented with animal protein, plant protein or non-protein nitrogen and sulphur
Authors: Siebert BD , Hunter RA , Jones PN
Published: March 2005

When sugarcane was chopped, supplemented with meat meal or the tropical legume Leucaena leucocephala and fed to Droughtmaster steers, they gained liveweight at the rate of 0.61 kg day-1. When non-protein nitrogen and sulphur were used as the supplement, animals lost liveweight initially but later gained liveweight at 0.52 kg day-1. The improvement was brought about by evenly distributing the supplement in the ration and by ensiling the treated feed for at least 24 hours. Cattle consumed approximately 71 g OM/kg LW0.75/day and digested 57.9 per cent of the diet when the protein source was L. leucocephala, 64.4 per cent when it was meat meal and 66.2 per cent when it was urea and sodium sulphate. The differences in digestibility were associated with differences in retention time of the diets in the rumen.
Temperature effects on the early field development of cotton
Authors: Constable GA
Published: March 2005

The germination and early development of cotton in the Namoi Valley, New South Wales, was examined in three seasons, and related to temperature by regression analysis and by growing degree day (GDD) summations. Temperature variation was achieved by planting date and season. It was found that cotton development between planting and squaring would cease below 11.4�C. A delay of one week in planting decreased the planting to emergence phase by 0.9 days, the emergence to squaring phase by 2.2 days and the squaring to flowering phase by 0.4 days. Therefore, the selection of cultivars for cold tolerance should concentrate on the emergence to squaring phase in particular. For wet soil, increasing temperature was strongly associated with per cent and speed of emergence. For dry soil, temperature had a smaller effect.
Breed and environmental factors affecting birth weight in Victorian beef cattle
Authors: Holland BJM , Mullaney PD , Hopkins IR
Published: March 2005

Birth weights of 2929 Angus, Hereford and Poll Hereford calves born between 1963 and 1970 on six properties in Victoria, Australia, were analysed to provide correction factors for the effect of dam age, calf sex and calving time. The unadjusted mean birth weight of all calves was 30.9 � 4.5 kg. Year of calving affected birth weight significantly on four out of five properties, although the effects of year and property were partially confounded. Calves from two, three and four-year-old dams were 15, 8 and 6 per cent lighter respectively, than calves from mature (5 to 8 years) dams. Male calves were significantly heavier by 1.86 kg than female calves; twin calves were significantly lighter by 7.0 kg than single-born calves. Calving time affected birth weight significantly on five out of six properties, with an increase in birth weight of approximately 1.0 kg per month from mid-autumn to mid-winter.
The relationship of age, body weight and factors associated with oestrus to non-return to oestrus of artificially inseminated Merino ewes
Authors: Watson PF , Martin ICA
Published: March 2005

In the course of three experiments involving the artificial insemination (Al) of flocks of 1230, 1240 and 1170 Merino ewes, observations were made at the time of A1 and were related to subsequent 28 to 45 day non-return rate (NRR). Ewes in oestrus were detected by vasectomized rams harnessed with marking crayons and the flocks were examined twice daily at 7.00 a.m. and 3.00 p.m. for 17 days. Significantly more ewes came into oestrus per unit time in the interval 7.00 a.m. to 3.00 p.m. than in the other 16 hours of the day. Age (range 2 to 7 years) and body weight (range 31 to 49 kg) of ewes did not affect NRR significantly. The intensity of the crayon marks left on the rumps of ewes by teaser rams was scored (1, faint; 2, distinct; 3, intense) and NRR was lowest where ewes had faint colour marks. The appearance and volume of vaginal mucus found at the time of A1 were scored on a scale (1 to 4) related to the sequence of changes occuring in mucus during the oestrous period. NRR was highest when a volume of 10 to 15 ml of mucus was present in the depths of the vagina. The structure of the vagina and external opening of the cervix was classified into one of six categories and NRR was significantly lower where the vagina was too narrow to permit the introduction of a speculum. In these cases the semen dose was deposited into the vagina without locating the cervical opening.
Some factors affecting the establishment of four native grasses
Authors: Hagon MW , Groves RH
Published: March 2005

The effects of fertilizer application, types of mulching and times of sowing on the field germination of seed of four native grasses (Themeda australis, Bothriochloa macra, Danthonia spp., and Stipa bigeniculata) are reported. Growth of these species in controlled environments was compared with that of Lolium perenne (ryegrass) at three temperature regimes and two levels of nutrition. Application of an NPK fertilizer had no effect on emergence or survival of the native grasses in the field. Mulching with paper or straw increased emergence of all four species and mulching with bitumen increased emergence from Themeda, Bothriochloa and Danthonia seed only, but decreased survival of the two latter species. In both field and controlled environments, germination and seedling growth of Themeda and Bothriochloa were best when maximum daily temperatures were greater than 30�, whereas Danthonia and Stipa germinated and grew most satisfactorily when maximum daily temperatures were about 25�. Growth of Stipa seedlings in a controlled environment was enhanced by a high level of nutrition but growth of the other species was not. Sowing seed in late spring and using a straw mulch should ensure satisfactory levels of establishment of native grass seedlings in the field in south-eastern Australia. Fertilizer application should not be necessary
Rapid changes in simple mixtures of Townsville stylo (Stylosanthes humilis) lines differing in flowering time and growth habit
Authors: Cameron DF , McCown RL
Published: March 2005

The ecological adaptation of Townsville stylo (Stylosanthes humilis) lines was studied by following changes in the composition of mixtures of the lines. At Weipa, a high rainfall site in north Queensland, the composition of a mixture of four maturity types changed rapidly in favour of the later flowering lines, and the earliest line was almost eliminated by the end of the second year. In binary mixtures at 'Lansdown' near Townsville, defoliation every six weeks favoured erect lines but the proportion of prostrate lines was almost doubled at the three week cutting frequency. Changes in mixture composition could not be related to the dry matter yield or pod yield of the monocultures at either site. The capacity of late flowering lines to increase rapidly in populations growing in high rainfall areas, as demonstrated at the Weipa site, could pose problems for the commercial seed production of earlier flowering lines in such areas.
Effects of zinc and iron fertilizers on a disorder in rice on the calcareous soils of the Ord Irrigation Area, Western Australia
Authors: Chapman AL , Boundy CAP
Published: March 2005

A field experiment was conducted at Kimberley Research Station near Kununurra, Western Australia to study the effects of urea and ammonium sulphate fertilizers, previous cropping history and method of sowing on the incidence of a long-standing disorder in rice on the calcareous soils of the Ord Irrigation Area, and to determine whether the disorder could be ameliorated by means of zinc and iron fertilizers. Symptoms of the disorder resembling those of zinc deficiency appeared within four weeks after seedling emergence in plots not treated with zinc. The mean concentration of zinc in the tops of affected plants sampled at 2, 7 and 11 weeks was 18 p.p.m. The combination of fallow land, urea and water-sowing resulted in the most severe symptoms. Where 20 kg Zn ha-1 was applied as zinc sulphate, the zinc concentration in the plant tops averaged 66 p.p.m. over the three sampling dates, and zinc deficiency symptoms did not develop. Other symptoms resembling those of iron deficiency also occurred, especially when the level of applied zinc was 20 kg ha-1. The application of both zinc sulphate and ferrous sulphate fertilizers resulted in a significant increase in the grain yield of IR665-24-1 rice. Overall there was no response to zinc sulphate above the level of 10 kg zinc ha-1. The curve of best fit for the overall response to ferrous sulphate was parabolic with a maximum near 240 kg ha-1 ferrous sulphate. The mean yield from plots that received three foliar sprays of 0.1 per cent ferrous sulphate was not significantly different from that of plots fertilized with 200 kg ha-1 ferrous sulphate. There was no significant interaction between zinc and iron.
Comparison of different mandarin scion-rootstock combinations at Mildura, Victoria
Authors: Thornton IR
Published: March 2005

Four mandarin varieties (Early Imperial, Emperor, Dancy and Ellendale) were budded on different rootstocks in 1958 and measurements of accumulated yield per tree and average individual fruit size were made from 1963 to 1973. Surface area of trees and scion-rootstock fruitfulness were calculated from measurements made in 1973, and financial returns for 1972 and 1973 were estimated from market reports. The greatest weight of fruit was produced by Dancy, Emperor and Ellendale, but Dancy produced a greater number of fruit. Order of average fruit size was Ellendale (largest), Emperor, Dancy, Early Imperial. Dancy trees were bigger than the others, and Emperor the smallest. The most fruitful scions were Ellendale and Emperor followed by Dancy and Early Imperial. Early Imperial earned the best gross financial returns per tree, followed by Ellendale and Dancy, then Emperor. Symons and Cox sweet orange and Emperor and Cleopatra mandarin rootstocks are recommended for use with all varieties to obtain the best yields, fruitfulness and financial return on soils similar to those of the trial. Present market demands indicate that preference for planting should be given to Early Imperial and Ellendale, and to a lesser extent, Dancy.
The effect of a phosphorus supplement on the performance of steers grazing Townsville stylo-based pasture in north Queensland
Authors: Winks L , Lamberth FC , O'Rourke PK
Published: March 2005

The effect of phosphorus supplementation on the performance of steeres grazing unfertilized native pasture and Townsville stylo (Stylosanthes humilis) with andwithout superphosphate fertilizer on the subcoastal spear grass region of the dry tropics of north Queensland was studied over a period of 40 months. Liveweight gains in the absence of supplementation on fertilized Townsville stylo pastures were greater than on unfertilized Townsville stylo, where performance was similar to that recorded on untreated native pasture. Phosphorus supplementation increased weight gains during the wet season on both unfertilized Townsville stylo and native pasture but had no significant effect on dry season performance or performance on fertilized Townsville stylo. Fertilized areas became dominated by annual grasses, Digitaria ciliaris and Brachiaria milliiformis, and legume yields were higher on unfertilized than on fertilized areas. Fertilizer improved the quality of available pastures.