bluuebunny/crossref_metadata_2025 huggingface dataset:
Superphosphate maintains soil fertility and beef production on grazed white clover pastures in the subtropics. 2. Liveweight responses of beef cattle
Authors: Mears PT , Cullis BR
Published: March 2005

Growth of cattle was measured between 1974-75 and 1980-81 on a white clover (Trifolium repens) and carpet grass (Axonopus affinis) pasture receiving superphosphate applied at 0, 12, 24, and48 kg P/ha annually. Hereford weaner steers grazed the pastures at 1.67, 2.5, and 3.3 steers/ha. Linear responses to superphosphate and stocking rate were significant (P<0.001). The model estimating steer liveweight response to superphosphate comprised a long-term quadratic trend with seasonal variations. The liveweight response to superphosphate application was greatest in liveweight response to superphosphate applied at12 kg P/ha increased from 6.1 kg/steer.45 days in year 1 to 10.6 kg/steer.45 days in year 7. Average liveweight responses to 48 kg P/ha also increased from 34.0 kg/steer.45 days in year 1 to 78 kg/steer.45 days in year 7. Annual liveweight gain of steers at the low stocking rate (1.67/ha) without superphosphate declined from 165 kg/steer in year 1 to 38 kg/steer in year 7, while 24 kg P/ha maintained liveweight gain at 120-220 kg/steer. Annual liveweight gain was negatively related to stocking rate, averaging -31.3 kg/steer for each increment in stocking rate. Calculated stocking rates giving maximum liveweight production (122-469 kg/ha) varied between 2.2 and 3.6 steers/ha. Annual liveweight gain of steers was related to bicarbonate-extractable soil P using the exponential model, which accounted for 19% spring and least in autumn each year. Seasonal of the variation.It was concluded that maintenance dressings of superphosphate would be required when available soil P levels fell below 30 mg/kg, in order to maintain liveweight gains on white clover-Axonopus pastures. The linear response model will assist producers to decide on rates of superphosphate.
Long-term effects of stubble management on the incidence of infection of wheat by Fusarium graminearum Schw. Group 1
Authors: Burgess LW , Backhouse D , Summerell BA , Pattison AB , Klein TA , Esdaile RJ , Ticehurst G
Published: March 2005

The effect of 3 stubble management regimes (burning after harvest, incorporation with a disc plough, retention on the surface) on the incidence of infection of wheat with Fusarium graminearum Schw. Group 1 was studied for 5 seasons at 2 sites at Moree, New South Wales. One site had high initial incidence (site A) and the other low initial incidence (site B). There were no differences in incidence of infection between retained and incorporated treatments. Stubble burning reduced the increase in incidence of infection in 2 of 5 years at site A and 3 of 4 years at site B. Failure of control in other years was attributed to susceptible weed hosts and poor burns. When stubble was retained on the plots at site B that had been burnt, incidence of infection in the next season increased to a level not significantly different from the retained or incorporated treatments. Incidence of infection at the fourth consecutive wheat crop at both sites was close to the maximum recorded, which was 92% at site A and 65% at site B. There was no evidence of a decline in incidence by the time of the most recent season assessed (eighth year of continuous wheat cultivation at site A, and sixth year at site B). In most years, the differences in yield between treatments were not significant.
Effect of lupins and pasture on soil acidification and fertility in Western Australia
Authors: Loss SP , Ritchie GSP , Robson AD
Published: March 2005

An 'across the fence' comparison of farmer paddocks with nearby virgin bush sites was made at 3 locations, to measure the effects of lupins and subterranean clover based pastures on the chemical properties of the soil. Estimated rates of acidification in the 0-60 cm depth were 0.29-0.55 kmol H+/ha.year for wheat-lupin paddocks and 0.16-0.2 1 kmol H+/ha .year for pasture paddocks. A significant proportion of this acidification occurred below 20 cm, particularly in the lupin paddocks (up to 70% of the total). Severe water repellency had developed at 1 location that had produced 30 lupin crops with the occasional wheat crop. Despite these detrimental effects, lupins maintained soil mineral nitrogen and organic matter contents and electrical conductivities similar to those in pasture paddocks, even though the soils in the lupin rotations had been sown to wheat more frequently.
Effect of fungicide seed dressings on leaf stripe of barley caused by Pyrenophora graminea S. Ito Kuribay
Authors: Loughman R , Khan TN
Published: March 2005

Eight fungicide seed dressings were evaluated in the southern cereal belt of Western Australia for control of barley leaf stripe caused by Pyrenophora graminea. Flutriafol (100 �g/g seed) and triadimenol plus imazalil (225 + 75 �g/g seed) were most effective. Control of leaf stripe with other fungicides depended on location. Imazalil appeared to be the ingredient most active against leaf stripe. Flutriafol and triadimenol plus imazalil offer effective control of leaf stripe and other endemic diseases (loose smut, powdery mildew, and scald) in the southern cereal belt.
Cereal stubble mulching protects lupins from brown spot [Pleiochaeta setosa (Kirchn.) Hughes]
Authors: Sweetingham MW , Loughman R , Porritt SE
Published: March 2005

Brown spot of lupins, initiated by rainsplash of soil-borne spores of the fungus Pleiochaeta setosa, was controlled by cereal stubble mulches. Stubble provided protection for longer in the season than fungicide seed dressing. At 1 site, late season pod infection was reduced by stubble mulch. Disease severity decreased with increasing quantity of stubble, but there was little benefit in retaining more than 2 t/ha of stubble. Grain yield was increased from 0.87 to 1.48 t/ha by retaining 2 t/ha of stubble at 1 site. The reduction in brown spot by stubble and fungicide was additive.
Postharvest floral organ fall in Geraldton waxflower (Chamelaucium uncinatum Schauer)
Authors: Joyce DC
Published: March 2005

Possible reasons for, and prevention of, postharvest floral organ fall in Geraldton waxflower (Chamelaucium unciizatum Schauer) were studied. An 11-kg compression load, equivalent to the lidding of a carton, caused flower fall amounting to 1% of the fresh mass of 420-g bunches. Fungal development also resulted in flower abscission. Healthy flowers produced little ethylene (e.g. 0.05 �L/kg.h), while infected flowers produced much more (e.g. 7.71 �L/kg.h) and were shed. Treatment with fungicide (iprodione + mancozeb) and antiethylene compounds [e.g. silver thiosulfate (STS) pulse, Purafil sorbant] reduced flowerfall in packaged flowers. Cut sprigs which suffered severe water deficit also shed flowers. In cv. Elegance, drying to -3.61 MPa elevated ethylene production (e.g. 1.35 �L/kg . h). Flowerfall induced by water deficit could be reduced by pretreatment with a STS pulse (0.5 mmol Ag+/L for 15-22 h at 0�C or 4 mmol Ag+/L for 20-30 min at about 20�C). Pretreatment with a naphthaleneacetic acid dip (50 mg/L for 1 min at room temperature) shortened the vase life of Elegance.
Residues in apples and their packaging following fumigation with methyl bromide
Authors: Jessup AJ , Sloggett R
Published: March 2005

Apples (cv. Granny Smith) were fumigated with 40 g methyl bromide/m3 for 2 h at 17�C, then aerated for 2 h and stored for 10 days at 1�C as a proposed quarantine schedule for export to Japan. Residues of methyl bromide decreased from 0.1 �g/g following fumigation and cold storage to <0.002 �g/g after a further 20 days at 1�C (to simulate shipping time to Japan). Statistical analysis estimated that methyl bromide residues would decrease to 0.001 �g/g after 14.2 days storage at 1�C after fumigation. Methyl bromide residues in apple carton materials decreased to <0.01 �g/g after 7 days at 1�C, and to below the detection limit (0.002 �g/g) after 7 extra days storage at 1�C. Inorganic bromide residue after fumigation and cold storage for 30 days was 3.9 �g/g. This was less than the maximum residue limit (5 �g/g) set by the US Food and Drug Administration.
Time of joining affects the performance of young Angus and Angus multiply Friesian cattle in the south-west of Western Australia. 1. Liveweight, body condition, and reproductive performance in heifers and first-calvers
Authors: Sawyer GJ , Milligan J , Barker DJ
Published: March 2005

A 3-year study using 183 Angus and 173 Angus x Friesian first-calf heifers joined at about 15 months of age was conducted to determine the effects of time of calving and breed on liveweight and condition, heifer reproductive performance, oestrus activity after calving, and subsequent conception. Pasture on offer and supplements were also measured. Calving times used were April (conventional calving time), March (4 weeks earlier), and May (4 weeks later). There was no significant effect of time of calving on net reproductive rate in heifers of either breed, but the number of stillbirths and dystocias in later calved Angus were greater than in Angus x Friesian. Protracted and difficult calvings were more prevalent in heifers of both breeds calving early. Highest pregnancy rates of 93-94% corresponded with the highest average liveweights at conception in nulliparous heifers of both breeds that were mated to first-calve later. Angus x Friesian first-calvers consistently returned to oestrus before Angus after their first calving. In a year when grazing pressure on depleted dry pasture residues caused significant liveweight loss in both breeds, the crossbreds commenced cycling, on average, 20-32 days before the Angus. Regression of calving date and length of the post-partum anoestrous interval (PPAI) was -0.54 days/day for Angus and -0.3 1 days/day for Angus x Friesian. There was no significant difference between breeds for time to conception. The regression of second conception date on first calving date was 0.10 days/day in Angus and 0.17 days/day in Angus x Friesian. Heavier first-calvers of both breeds returned to oestrus earlier; each extra 10 kg in liveweight was associated with shorter PPAI by 3.9 days in Angus and 1.7 days in Angus x Friesian crossbreds. Heavier first-calvers of both breeds also conceived earlier; however, about twice as much weight was required to reduce the time to conception in the larger Angus x Friesian crossbreds than in the Angus. Times to first oestrus and to conception were negatively and linearly related to condition only in Angus first-calvers. Conception rates after first calving did not differ between time-of-calving groups or breeds in 2 years, but in a difficult year and if calved later, only 73% of Angus and 61 % of Angus x Friesians were pregnant after 90 days of joining. We conclude that there is little justification on the grounds of reproductive performance for varying the time of calving of heifers from that of the main breeding herd.
Maize silage for the pasture-fed dairy cow. 5. A comparison with wheat while grazing low quality perennial pastures in the summer
Authors: Moran JB , Croke DE
Published: March 2005

Dairy cows in mid lactation grazed paspalum-dominant perennial pastures and were offered either crushed wheat or maize silage at 0, 25, 50, or 75 MJ metabolisable energy/cow.day. Another herd was offered maize silage ad libitum. Milk yield and composition, liveweight and body condition, and pasture intakes were monitored over 8 weeks during summer. Cow performance was recorded for another 3 weeks when all cows were supplemented with the same feedlot ration. Samples of pastures before and after grazing, supplement, rumen fluid, and faeces were collected for chemical analyses. Linear regressions were used to calculate mean milk responses and rates of pasture substitution for the 2 supplement types. Yields of milk and milk solids increased with level of supplement fed (with 1 exception) and were higher in cows fed wheat at the same level of supplemental energy. However, cows fed maize silage achieved higher body condition scores. On average, cows supplemented with wheat and maize silage, respectively, produced 0.72 and 0.38 kg extra milk/kg supplement (DM), and they substituted pasture at the rate of 0.87 and 1 .O1 kg pasture DM/kg supplement DM. Low pasture quality (117 g crude protein/kg DM and 59.5% in vitro digestibility) was considered the main cause of high levels of pasture substitution and poor milk responses to maize silage feeding. Cows fed 6.8 kg DM/cow.day of maize silage had very low rumen ammonia-N and faecal N concentrations. It was concluded that additional N should be included with maize silage when fed to cows grazing low quality perennial pastures, even with feeding levels as low as 2 or 3 kg DM/cow.day.
Herbage and animal production from native pastures and pastures oversown with Stylosanthes hamata. 1. Fertiliser and stocking rate effects
Authors: Gardener CJ , McCaskill MR , McIvor JG
Published: March 2005

Native pastures dominated by Heteropogon contortus (speargrass) were sown to Stylosanthes hanzata cv. Verano in 1972, and herbage production and steer growth rates were compared with those of native pastures from 1973 to 1985. The native pastures also contained naturalised Stylosanthes humilis, but its contribution to pasture yield diminished rapidly, after infection by Colletotrichum gloeospoirioides (anthracnose) in 1973. The experiment was a factorial design of 2 pasture types (native, native plus Verano) x 2 stocking rates (0.6, 1.2 steers/ha) x 2 superphosphate treatments (nil, 300 kg/ha.year) x 2 replicates. Fertiliser application decreased the proportion of legume but had no significant effect on herbage or animal production on this comparatively fertile site (extractable P, 18 mg/kg). Annual liveweight gains at the high and low stocking rates, respectively, on the native pasture averaged 100 and 120 kg/steer. Sowing to Verano did not affect herbage yields but increased annual liveweight gains by 28 and 36 kg/steer at low and high stocking rates. The high stocking rate of 1.2 steers/ha was sustainable for the first 9 years of the experiment, when above-average rainfall was received. However, in the following 3 below-average years, there was a shift to less-desirable species, and a decline in pasture productivity. Relative to the low stocking rate, herbage production on the native pasture in the final season was reduced by 60% and on the Verano pasture by 26%. The highest annual herbage utilisation rate that appeared sustainable in the long term was about 45%, which corresponded to a utilisation rate of 30% during the growing season (about November-May). When oversown with Verano, speargrass tended to decline in favour of annual grasses, weeds, and the introduced grass Urochloa mosanzhicensis, which had been sown on an adjacent experiment. Urochloa appeared to be a more suitable companion species than speargrass for Verano.
Herbage and animal production from native pastures and pastures oversown with Stylosanthes hamata. 2. Modelling studies
Authors: McCaskill MR , McIvor JG
Published: March 2005

Data from a long-term grazing experiment were used to develop relationships suitable for modelling between-year variation in pasture and animal production. The experiment was conducted near Townsville in North Queensland and consisted of a factorial combination of 2 stocking rates (0.6, 1.2 steers/ha) x 2 pasture types (native pasture, native pasture plus Stylosanthes hamata cv. Verano) x 2 superphosphate rates (nil, 300 kg/ha.year). Cattle were weighed monthly, and the herbage presentation yield and stylo content estimated annually. Relationships between annual liveweight gain (LWG) and a range of climate-derived parameters including the number of 'green days' were calculated from a water balance and pasture growth model. When a different intercept was allowed for each pasture and stocking rate combination, there was a strong relationship between annual LWG and the number of 'green days' (R2 = 0.78). In a more general relationship, LWG was related to green days, stylo content, and utilisation rate (R2 = 0.58). No relationships was found that would enable reliable prediction of between-year variation in the pasture attributes of stylo content and the water use efficiency of herbage growth. The times of the year when daily rates of LWG changed could be predicted satisfactorily, but rate of gain within each phase varied considerably from year to year. Differences in LWG between stocking rates occurred when there would have been restricted amounts of new green feed, or of stylo in the late wet season.
Comparison of the performance of subterranean clover cultivars in southern New South Wales. 1. Persistence, productivity, and seed yields
Authors: Dear BS , Cregan PD , Murray GM
Published: March 2005

The density, productivity, flowering characteristics, and seed reserves of 14 lines (10 cultivars and 4 experimental lines) of subterranean clover were observed over 5 years (1983-87) on a red earth soil at Wagga Wagga, New South Wales. Plant density increased from 149-318 plants/m2 in 1983 to 1975-13925 plants/m'n 1987. Herbage yields of all cultivars during autumn-winter were similar in most years except in July 1985 when Seaton Park was superior. Cultivars in the midseason or later flowering groups were more productive in late spring and better able to utilise the extended growing seasons that occur periodically in this environment. The mean time from emergence to 5% flowering of all cultivars was 168 days with March germination in 1985 but decreased to 13.5 days with May germination in 1986. The number of days to flowering at Wagga Wagga was highly correlated with maturity ranking at Perth (r2 = 0.92 in 1985 and? = 0.93 in 1986). In the first year, average seed set was 295 kg seed/ha. but by summer of the fourth year the seed pool ranged from 124 kg/ha for Clare to 1190 kg/ha for Nungarin, the earliest flowering cultivar. The quantity of hard seed that carried over to the next year varied significantly between cultivars, with Enfield, Woogenellup, and Clare having the least, and Nungarin, Northam, Dalkeith, and Daliak the most. Seed set was related to maturity ranking only in 1984, although root disease probably affected seed yields in 1985-86. The proportion of hard seed that carried over was much higher than expected, particularly in soft-seeded cultivars. The newly released cultivar Junee was well adapted to the environment; it was later maturing than the recommended cultivar Seaton Park but was able to maintain high seed reserves. Karridale, another new cultivar, maintained higher seed reserves than the older Mount Barker.
Measuring the response of pasture to superphosphate using aircraft and satellite remote sensing
Authors: Reid RND , Vickery PJ , Hedges DA , Williams PM
Published: March 2005

Remote sensing measurements in the visible, near infrared, and short-wave infrared were made on experimental areas of grass-legume pasture with different fertiliser and stocking rate treatments and on commercial pastures with added fertiliser.Divisive classification and ordination analyses of the remotely sensed data were used to allocate the image data to 11-15 classes from measurements in 2 successive years The resultant data were displayed on an image processing system which showed that the fertilised areas belonged to classes different from those without fertiliser. Soil and plant nutrient tests revealed differences between treated and untreated sites as mapped from the remote sensing data.
Genotype multiply environment interactions in progeny from a barley cross. 1. Patterns of response among progeny lines for grain yield and time to anthesis
Authors: Jackson PA , Byth DE , Johnston RP , Fischer KS
Published: March 2005

Barley progeny lines (201) derived from F2 plants of the cross cv. Triumph x cv. Grimmett were evaluated at 7 environments in Queensland. Cluster analysis and principal component analysis were used to examine the variation in response for grain yield. The relationship between days to anthesis and these responses was investigated. The variance component for genotype x environment (GE) interaction for grain yield was of similar magnitude to that for line main effects. Groups of lines formed using cluster analysis exhibited substantial differences in ranking across environments, indicating that selection would be affected by choice of test environments. The components of grain yield, harvest index (HI), and total dry matter (TDM) had large variation for GE interaction. However, for days to anthesis, the variance component for GE interaction was small compared with that for the line main effects. There were significant differences in mean days to anthesis for groups of lines that were classified on the basis of grain yield. Early flowering was associated with high grain yield in some environments but with low grain yield in the 2 irrigated environments. The first component from principal component analysis of grain yield was only weakly related to days to anthesis. This component appeared to be related to performance in favourable environments, suggesting that an important source of variation in grain yield among the progeny lines was associated with their responsiveness to favourable conditions.
Phytotoxicity of several pre-emergence and post-emergence herbicides to green beans (Phaseolus vulgaris)
Authors: Henderson CWL , Webber MJ
Published: March 2005

The phytotoxicity to green beans (Phaseolus vulgaris) of the herbicides metolachlor, pendimethalin, cyanazine, acifluorfen, diflufenican, bentazone, metribuzin, prometryn, terbutryn, methabenzthiazuron, and oxyfluorfen was investigated in 4 experiments on a black earth soil (clay content 40-60%) at Gatton Research Station in southern Queensland during 1990-91. Metolachlor was applied post-sowing and pre-emergence; up to 4 kg a.i./ha did not significantly (P>0.05) affect growth or yields, indicating a considerable safety margin for this herbicide when used at commercial rates. Pendimethalin did not cause significant crop damage when applied in the same manner at rates up to 2.7 kg a.i./ha. Acifluorfen and diflufenican were each applied at 3 or 4 weeks after sowing in 3 experiments. Sensitivity of the bean crop to acifluorfen varied: 0.5 kg a.i./ha did not significantly reduce bean growth or yield in 2 experiments, but 0.11 kg a.i./ha reduced yields by 20% in a third experiment. Application of 0.1-0.12 kg a.i./ha of diflufenican had no adverse effect on beans in 2 experiments, although significant damage was observed in an initial screening experiment. Bentazone applied 3 weeks after sowing had no significant effect on bean yield or growth in 1 experiment; in another, the maximum label rate of 0.96 kg a.i./ha significantly reduced bean growth and yield. Post-emergence application of cyanazine, metribuzin, prometryn, terbutryn, methabenzthiazuron, or oxyfluorfen at rates required for acceptable weed control either killed the bean plants within a few days or resulted in complete yield loss. Levels of damage from these herbicides preclude their use in green beans. Although green beans showed some tolerance to postsowing, pre-emergence application of cyanazine, low rates of 0.75-1 kg a.i./ha reduced yields by 35%. Both metolachlor and pendimethalin appear suitable for pre-emergence use in green beans. Further work on factors affecting phytotoxicity of acifluorfen, diflufenican, and bentazone to green beans is required.
An evaluation of cattle types for north-western Australia
Authors: Pratchett D , Wallace J , Young S
Published: March 2005

An evaluation of calving rate and cow mortality in the Kimberley region of Western Australia was made for 6 breeder groups: Shorthorn, Brahman, F1 Brahman x Shorthorn (F1BS), F1 Africander x Shorthorn (F1AS), F, Brahman x Shorthorn (F2BS), and F2 Africander x shorthorn (F2AS). From these 6 breeder groups, 8 steer lines were produced: Shorthorn, Brahman, F1BS, F2BS, F3BS, F1AS, F2AS, and F3AS. These were evaluated for calf survival, calf growth, steer mortality, steer growth, and steer carcass weight. There were significant (P<0.001) year and breed effects on calving rate. F1BS and F1AS showed the highest calving percentage, with corrected means of 60 and 61% for the whole herd and 67 and 66% when 15-month-old heifers were excluded. The calving rate in F2BS dropped to 49%, while that in F2AS was maintained at 67%. Few cows died in any group and it was not possible to detect differences between breed types. Likewise, few steers died after 12 months of age. The lowest mean weaning weight of 116 kg in July at 6 months of age was recorded for Shorthorn calves; the highest was recorded for F2BS at 174 kg. However, the advantage was not maintained until November when the calves were 10 months old. Brahman and F1BS had superior growth rates from weaning to 10 months. There were significant (P<0.001) breed and year effects on steer liveweight at all weighing dates. After the first November weighing, Brahman and F1BS made the greatest liveweight gain. All breeds lost weight in the second dry period. At 27 and 39 months, F1BS steers had the heaviest carcass weights of 222 and 300 kg. F2AS and F3BS steers had the lowest carcass weights at both times (174 kg at 27 months and 22 kg at 39 months).
Effects of supplementation with safflower oil on voluntary feed intake and tissue fatty acid composition of steers fed low quality hay ad libitum
Authors: O'Kelly JC , Spiers WG
Published: March 2005

The effect of safflower oil supplement (200 mL/day) on voluntary feed intake and fatty acid composition of plasma, blood platelets, subcutaneous adipose tissue, and M. longissimus dorsi muscle was studied in Brahman steers consuming a low quality hay. The initial mean liveweight (LW) of the steers was 197 kg. Mean LW gain over 50 days was 20 kg for all steers, but voluntary feed intake (5.63 kg/day) was reduced by 1.02 kg/day with safflower oil. Supplementation increased the plasma concentrations of unsaturated fatty acids, indicating a less complete hydrogenation of dietary safflower oil than of hay by rumen microorganisms. Safflower oil altered the fatty acid (FA) profiles of platelet and muscle phospholipids. with increases in the proportions of monounsaturated acids (MFA) and polyunsaturated fatty acids (PFA) and associated decreases in the proportions of saturated fatty acids (SFA). The neutral lipids of adipose tissue consisted of 60% SFA and 38% MFA in steers fed hay alone, compared with 53% SFA and 45% MFA in supplemented steers. Safflower oil had no effect on the total fat content of muscle; the concentration of PFA was not significantly altered, but SFA decreased 17% in parallel with a 23% increase in MFA. The results support proposals that dietary oil supplements may be used to reduce forage intake during dry season or drought, to conserve body protein and to modify the FA composition of meat phospholipids which may, in turn, influence meat quality of ruminants consuming low quality roughage diets.
Effect of divergent selection for weaning weight on liveweight and wool growth responses to feed intake in Merino ewes
Authors: Herd RM , Oddy VH , Lee GJ
Published: March 2005

During a 6-week experiment, the feed requirements for maintenance of liveweight (LW) by adult Merino ewes were measured in 2 flocks selected over 32 years for divergent weaning weight. Also examined were the net efficiency of LW gain and wool growth in response to change in feed intake, and the ability to digest dietary organic matter. Ewes selected for high weaning weight (W+) were 31% heavier than those selected for low weaning weight (W-) at the start of the experiment. To maintain LW, W+ ewes ate 24% more digestible organic matter (DOM) per day than W- ewes. There were no differences (P>0.2) in the net efficiency of feed use for LW gain. The W+ ewes digested more (P<0.01) dietary organic matter, by 1.8 percentage units, than W- ewes and, consequently, required only 22% more dry feed to maintain their heavier LW. Ewes from the 2 flocks did not differ (P>0.4) in the amount of wool grown, and as W+ ewes were larger, they produced less (P<0.01) wool per kg LW for the same DOM intake.
Changes in fat depths and muscle dimensions in growing lambs as measured by real-time ultrasound
Authors: Hopkins DL , Pirlot KL , Roberts AHK , Beattie AS
Published: March 2005

Carcass characteristics of 3-4-month-old lambs from 2 experiments were measured with a real-time ultrasound scanner 4 times over 4 months. In experiment 1, all lambs grazed 3 pasture regimes consecutively over 4 months, and in experiment 2, 3 nutritional treatments were compared. Lambs contemporary to these, from a third experiment, were scanned before slaughter, and the equivalent carcass measurements obtained. Significant (P<0.001) changes in GR tissue depth, subcutaneous fat depth at the C site, and M. longissimus thoracis et lumborum (LD) dimensions were detected as liveweight increased with time in experiments 1 and 2. Depth of LD was found to increase more than width during the growth phase studied. High repeatabilities were obtained for GR, with partial correlations of 0.72 and 0.86, using liveweight as the adjustment factor. For fat depth, repeatabilities were moderate at 0.57 and 0.73, respectively. An inconsistent result was found for LD depth and width, with correlations of 0.68 and 0.29 for depth and 0.36 and 0.5 1 for width. In experiment 3, there were small differences between GR, fat depth, and the area of the LD muscle as measured in vivo and on the carcass, but the accuracy with which fat depth could be estimated from ultrasonic measurements for individual lambs was low compared with the GR measurement. Depth of LD measured in vivo was significantly (P<0.001) greater than on the carcass, but the converse was true for LD width, indicating a change in shape. Partial correlations between in vivo and carcass measures were 0.60 for GR, 0.17 for fat depth, 0.36 for LD depth, and -0.15 for LD width. For LD area, there was a range of 0.31-0.42 depending on the method used to determine area on the carcass. It was considered that real-time ultrasound offered potential when used to monitor changes in GR. Measurement of fat depth in lean lambs was subject to significant error and is not recommended. Of the muscle dimensions, LD depth offers potential, but repeatability may be unsatisfactory in lightweight lambs.
Improving production from September-born Merino lambs with a lupin grain supplement and phomopsis-resistant lupin stubbles
Authors: Morcombe PW , Allen JG
Published: March 2005

As a means of providing nutrition on dry pasture in the wheatbelt of Western Australia, supplements of lupin grain were fed to late-born Merino lambs and their dams before weaning onto lupin stubble. Each ewe-lamb pair consumed an average 19.5 kg lupin grain over the 46 days before weaning. This produced an extra 3.6 kg (P<0.01) liveweight gain by these lambs compared with their unsupplemented cohorts at weaning. The growth of the weaned lambs grazing phomopsis-resistant lupin stubbles was primarily influenced by the amount of residual lupin grain available to each sheep and liver injury caused by ingestion of phomopsins. In the first 69 days of stubble grazing, sheep stocked at 10ha gained 7.3 kg while those stocked at 20ka gained 2.1 kg (P<0.001). In the first 13 months of life, lambs supplemented with lupin grain before weaning grew more (P<0.05) clean wool by 0.17 kg than the unsupplemented lambs. However, the value of this extra wool would not have covered the cost of the lupin grain eaten. Wool staples produced by sheep grazed at 10/ha on lupin stubble were stronger (P<0.001) than those produced by sheep grazed at 20ha (24.4 v. 17.7 N/ktex). The position of greatest weakness in the staple coincided with weight loss prior to removal from the stubble. Singleton lambs born in September and weaned onto a phomopsis-resistant lupin stubble reached liveweights consistent with survival over the summer and good productivity in their first year of life. The effects of lupinosis and reductions in wool staple strength may have been avoided by monitoring liveweight change and taking the sheep off the stubbles when they were near peak liveweight.
Effect of age and parity on maternal behaviour in single-bearing Merino ewes
Authors: Alexander G , Bradley LR , Stevens D
Published: March 2005

Behavioural factors associated with lamb mortality were examined in regard to the relative effects of age and parity in single-bearing Merino ewes. Primiparas tended to have longer labour and higher lamb mortality than multiparous ewes. Maternal behaviour in primiparas was characterised by more desertions, a smaller proportion that stood and started to groom their lambs immediately after birth, and a larger proportion with non-cooperative behaviour during the initial sucking attempts of the lamb. These traits, and a high incidence of malpresentations, were particularly marked in 5-year-old primiparas deliberately denied access to rams in previous seasons. There was no evidence of improved maternal behavioural attributes associated with increasing age of ewe that were independent of previous experience in giving birth and rearing lambs.
Barley grass control with herbicides in subterranean clover. 2. Effect on pasture and wheat in the year following spraying
Authors: Stephenson DW
Published: March 2005

Barley grass (Hordeum spp.) in a subterranean clover pasture was controlled using herbicides at different growth stages in 1988. The residual effects of these treatments on a naturally regenerating pasture and on wheat were investigated in 1989. Barley grass control carried over into 1989 but there was no increase in subterranean clover seedling density 1 resulting from legume dominance in 1988. Dry matter I production in early winter, on plots treated with herbicide in 1988, was reduced by up to 62% compared with unsprayed pasture, and the proportion of other broadleaf weed species increased. Wheat yields were increased by 3-11% where barley grass was controlled with fluazifop-p in the previous pasture. Available soil moisture at sowing was lowest following pasture that was unsprayed in 1988. No effect on the level of take-all (caused by Gaumannomyces graminis var. tritici) was evident. A replacement graminaceous species should be introduced into the pasture following barley grass control so that animal production and soil conservation are not disadvantaged. A disease break for a following cereal crop can be maintained by sowing an oat cultivar that is resistant to cereal cyst nematode (Heterodera avenae).
Temperature and water requirements for germination and emergence of lupin
Authors: Dracup M , Davies C , Tapscott H
Published: March 2005

The responses of germination, emergence, and pre-emergent growth of narrow-leafed lupin (Lupinus angustifolius L.) to a range of soil temperatures and matric potentials were determined in 2 replicate experiments with different seedlots and sowing techniques. Although absolute responses to temperature and water availability differed between experiments, the patterns of the responses did not. Optimum temperatures were close to 20�C and base temperatures were 0-3�C. At temperatures >23�C, germination and growth were highly variable and hindered estimation of ceiling (maximum) temperatures; the lowest was about 30�C for germination. Under optimum conditions, germination took 1-1.5 days and emergence from a depth of 4 cm took 4-4.5 days, equating to 75�C. day (base temperature 2�C). The minimum soil matric potential for growth was -1 to -2 MPa, and emergence was more sensitive to low matric potential than was germination. Hypocotyl extension was more sensitive than radicle extension to low matric potential, leading to relatively long roots at the time of emergence.
Selecting disease-resistant citrus rootstocks
Authors: Broadbent P , Gollnow BI
Published: March 2005

Hybrid rootstocks from a United States Department of Agriculture citrus breeding program were compared for their resistance to phytophthora collar rot (caused by Phytophthora citrophthora) and citrus tristeza virus (CTV), with 6 rootstocks used commercially in Australia. Rootstocks most resistant to collar rot were clone 22 of Poncirus trifoliara, F1 Cleopatra mandarin x English P. trifoliara, and Benton citrange. Mean lesion lengths for F1 Sunki mandarin X Mars P. trifoliata, Troyer citrange, (Rangpur lime x Swingle P. trifoliata) open pollinated, and F, Cleopatra mandarin X Christiansen P. trifoliata were not significantly different from clone 22 of P. trifoliata. Some P. trijoliata hybrids were more susceptible to collar rot than sweet orange, Cleopatra mandarin, or rough lemon. High titres of CTV in ELISA tests were evident in some hybrids, but only 1 F1 Rangpur lime X Carrizo citrange developed stem pitting symptoms. CTV titres in late spring (November) were higher in bark than in leaves.
Vegetative compatibility and distribution of Fusarium oxysporum f.sp. cubense in Australia
Authors: Moore NY , Pegg KG , Allen RN , Irwin JAG
Published: March 2005

Isolates of Fusarium oxysporum f. sp. cubense from wilted banana plants in Queensland and New South Wales were characterised for vegetative compatibility. Six vegetative compatibility groups VCGs) were identified. Race 1 (VCGs 0124, 01241.5, 0125) was widespread, being detected in northern and southern Queensland as well as northern New South Wales. Race 2 (VCG 0128) was found attacking Bluggoe in North Queensland. Race 4 (VCGs 0120, 0129, 01211) was detected in Cavendish plantations in southern Queensland and in Lady finger plantations in New (South Wales and southern Queensland. Isolates of the race 4 VCG 0129 from Lady finger plantations were pathogenic to Cavendish cultivars in glasshouse tests.
Meat yield and subjective muscle scores in medium weight steers
Authors: Perry D , Yeates AP , McKiernan WA
Published: March 2005

The association between visually assessed muscle scores on live steers and their carcasses, eye muscle area, and the yield of saleable and lean meat was determined on 156 steers of mixed breeds (mean carcass weight 282 kg, mean P8 fat depth 13 mm). The contribution of subcutaneous and intermuscular fat to differences in saleable meat yield was also investigated. There was a negative correlation between P8 fat depth and both live ( r = -0.21) and carcass muscle score (r. = -0.31); therefore, the assessors were not scoring fatter steers as having better shape. The correlation between live and carcass muscle scores was 0.79. The correlation between carcass muscle score and eye muscle area was 0.58. When live muscle score, carcass muscle score, or eye muscle area was included in regression models already containing weight and fat depth, there was a significant (P<0.001) increase in the amount of variation in saleable and lean meat yield explained by the models. At the same liveweight and fat depth, a change in live muscle score from C (moderately muscled) to B (well muscled) was accompanied by an increase of 1.7% in saleable meat and 2.2% in lean meat, when these were expressed as a percentage of carcass weight. The equivalent change in carcass muscle score in carcasses of the same weight and f a t depth was accompanied by an increase of 1.9% in saleable meat and 2.4% in lean meat. The increased weight of saleable meat was not due to an increase in the dissected fat content of the meat. Weight of subcutaneous fat decreased as muscle score increased (P<0.01). There was no significant association between the amount of intermuscular fat and either live or carcass muscle score (r. = -0.075 and -0.18, respectively).
Aspects of heifer management which limit productivity on dairy farms in Western Australia: a survey
Authors: Hough GM , Sawyer GJ
Published: March 2005

In 1989, a survey of 53 producers from the major dairy areas of the south-west of Western Australia was conducted to determine current management practices for dairy heifers and to identify of areas of heifer management which could be improved to increase overall farm productivity. Total farm size averaged 220 ha, with an average market milk quota of 699 L/day (50% of total milk produced). One-third of producers described their farm activity as dairying only. Some 116 calves were born per farm, with a year-round calving distribution. Calves were fed 5.4 L whole milk/day, with an average age at weaning of 13 weeks (range 5-26 weeks). Mortality recorded to 3 months of age was 4% and the most important health problem associated with calf rearing was scours. Of those properties with a health problem, 25% used antibiotics on a regular basis. All producers provided supplementary feed pre-weaning. In the period between weaning and mating, more than half the producers ran heifers on paddocks 3-80 km distant from the main farm, with hay the most common form of supplementary feed. Most dairy heifers were naturally mated to Hereford, Friesian, or Angus sires; hence, few heifers from first calvers were kept as dairy replacements. Average age at first calving was reported to be 30 months, with 1 in 9 heifers culled post-calving, generally for low milk production. The survey highlighted several aspects of heifer management with the potential to improve overall productivity of dairy farms in Western Australia. They include earlier weaning, strategic use of antibiotics to prevent the development of antibiotic resistance, greater use of artificial insemination, and a reduction in age at first calving.
A rod-point technique for estimating botanical composition of pastures
Authors: Little DL , Frensham AB
Published: March 2005

A simplified point method, the rod-point technique, for determining pasture botanical composition was assessed against 3 other popular methods. It was over 100 times faster than the traditional cut and hand-separate technique for the same level of precision. The presence of bias in the rod-point technique was assessed by comparing its estimates with those obtained by the hand-separation method. The pasture was classified into 8 botanical components, and the rod-point technique was significantly different from the hand-separated method in 3 instances, but in each case so were the Levy-point and the dry-weight-rank methods or the dry-weight-rank method alone. The rodpoint technique is most useful in large grazing trials, on-farm pasture monitoring, and pasture surveys. It provides a simple alternative for estimating pasture composition, using low inputs of materials, time, and labour.
Cropping practices in the Victorian Mallee. 1. Effect of direct drilling and stubble retention on the water economy and yield of wheat
Authors: Incerti M , Sale PWG , O'Leary GJ
Published: March 2005

Two experiments were conducted at the Mallee Research Station, Walpeup, between 1985 and 1989 to evaluate the impact of conservation farming practices on wheat yields. The first experiment compared wheat crops established by direct drilling into a chemical fallow with those conventionally sown into a cultivated fallow. Over the 5 years, yields ranged from 1.31 to 3.24 t/ha, and there was no reduction in crop yield associated with chemical fallowing and direct drilling compared with the cultivated fallow. There was also no significant effect of the chemical fallow on the amount of water conserved in the soil at sowing, at depth 0-100 cm; the range was 206-274 mm water. The second experiment from 1987 to 1989 examined the effect of maintaining 4 rates of stubble (0, 0.5, 1.0, 2.0 t/ha) on the surface of a conventionally cultivated long fallow. Stubble maintained at 2 t/ha increased the amount of water stored in the soil at sowing, at depth 0-140 cm, by 16 mm in 1 year of 3. This increase in soil water availability was not reflected in increased crop yield. These findings indicate that erosion control and potentially lower production costs associated with direct drilling and stubble retention can be achieved without loss of wheat yield in the Victorian Mallee.
Cropping practices in the Victorian Mallee. 2. Effect of long fallows on the water economy and the yield of wheat
Authors: Incerti M , Sale PWG , O'Leary GJ
Published: March 2005

Two experiments were conducted at the Mallee Research Station, Walpeup, between 1985 and 1989 to determine whether increases in wheat yield that occur after long fallows result from improvements in the supply and use of additional soil water conserved during the fallow. Although long fallows increased the amount of water stored in the soil at sowing (average 22 mm) and the yield of wheat (0.26 to 1.37 t/ha) in the first experiment, the results suggest no causal relationship between these increases. Improvements in wheat yield were attributed to increases in soil nitrogen availability and to control of cereal root diseases rather than to any increase in soil water conservation. This was confirmed in the second experiment, which was managed to ensure that nitrogen supply and cereal root diseases were not limiting crop production. Increases in soil water content at sowing resulting from long fallows did not result in higher wheat yields. This study suggests that long fallows cannot be justified on the basis of this increased soil water storage, as much of the additional soil water accumulated during the fallow period is stored in the lower part of the rootzone. Movement of this water below the rootzone during the growing season appears to be the main reason for the additional water stored at sowing, with long fallows failing to increase wheat growth and yield.
A comparison of different tillage-seeding systems: the interaction of tillage and time of sowing on sandplain soils in Western Australia
Authors: Schmidt CP , Belford RK
Published: March 2005

The effects of tillage-seeding method and 2 times of sowing on yields of wheat (Triticum aestivum) were examined on the sandplain soils in the northern wheatbelt of Western Australia. Four methods were compared: sowing after cultivation, sowing followed by deep ripping, direct drilling (i.e. single-pass seeding with a tined drill), sowing with a new cultivation depth modified drill (CDM) modified to cultivate up to 14 cm deep while sowing at 4 cm. Crops direct-drilled with the CDM produced more grain than crops established with conventional direct drilling or 'crops sown later using the cultivate-sow method and had similar yields to late-sown deep-ripped crops, where appropriate cultivars were used. Early sowing followed by deep ripping produced the highest grain yield. However, increasing the depth of soil disturbance while sowing early with the CDM in a 1-pass system resulted in a progressive increase in grain yield. When the cost of the extra ripping or cultivation operation is taken into account, early direct drilling with the CDM drill is likely to be more profitable than either conventional direct drilling or sowing with deep ripping or cultivation.