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Context Soybean cultivation is advancing over areas traditionally used for livestock production in southern Brazil, which has led producers to decide whether to diversify their production system or keep it specialised. Aims To evaluate the economic returns and risk for beef cattle production, as a specialised activity or an integrated system with soybean, in a high-risk region for soybean crop failures in southern Brazil. Methods Using a stochastic model, we evaluated the gross margin per hectare, the risk of negative gross margin per hectare, and the contribution of input variables to the gross margin per hectare variance. Therefore, the following three production systems were simulated: beef cattle production (BP), beef cattle production associated with leasing land for soybean cultivation (BSL), and beef cattle production with soybean cultivation (BSC). Key results All systems had a positive average gross margin per hectare, with BSL (US$125.69) having the highest average, followed by BSC (US$77.82) and BP (US$69.54). The highest difference between maximum and minimum values of gross margin per hectare was observed in the BSC, which was the only system to present a negative gross margin per hectare. This is owing to the high variation in the gross margin per hectare generated by soybean production activity, which made BSC the system with the greatest risk. Beef cattle average productivity from the integrated systems was 50% higher than the average observed in BP, with the minimum values in BSL and BSC being only 5.84% lower than the BP average. The risk components linked to soybean productivity (69.54%) and sale prices (17.32%) explained 86.86% of the variation in gross margin per hectare in the BSC. In BP and BSL, stocking rates (40.06% and 42.85% respectively) were the components with the greatest effect, followed by male and female selling prices, which explained 78.13% and 76.71% respectively, of the variation in the gross margin per hectare. Conclusions The system with the most significant balance between risk and economic return was BSL, with a higher gross margin per hectare than in BP and lower risk than in BSC. Implications Understanding the risk for negative economic results and the factors that affect the gross margin per hectare will help farmers decide whether to integrate soybean cultivation with beef production. These results will help inform the structure of the integration, and implementation of risk mitigation and loss minimisation strategies.

Choice of sheep-management system alters both production potential and the production risk due to variability in seasonal conditions. This study quantified production and gross margins from systems based on Merino ewes and varying in stocking rate, time of lambing, and the proportion of ewes joined to terminal-breed or Merino rams. Simulation studies were conducted between 1971 and 2011 using the AusFarm decision-support tool for a grazing property in southern New South Wales. Joining between December and May resulted in higher gross margins than in other months because of higher numbers of lambs sold combined with a lower requirement for supplementary feeding. More ewes could be carried per hectare for April joining than February joining to achieve the same midwinter stocking rate and risk of feeding. Self-replacing systems could produce median gross margins similar to those with replacement ewes purchased, but gross margins were sensitive to the cost of replacement ewes. Of the systems compared, February joining to Merino rams produced the lowest gross margins at all stocking rates, but this system also had the lowest variability among years. The advantage of different systems was dependent on seasonal conditions, which altered lamb production and supplementary feeding. The median ranking of systems for gross margin generally did not alter with changes in feed, sheep or wool values. Large increases in gross margins can be achieved through use of terminal-breed rams, optimal stocking rates and time of lambing, but the superiority of any option depended on production system, price assumptions and seasonal conditions.

The present paper focuses on the economic evaluation of the observed differences in maternal productivity of different genetic lines in Angus cattle that were managed under contrasting nutritional regimes typical of southern Australia. Five hundred Angus cows were managed concurrently at two locations in southern Australia. On each site, the cows were managed under the following two different nutritional treatments: High and Low, to simulate different stocking rates. Cows selected for a divergence in either carcass rib-fat depth or residual feed intake based on mid-parent estimated breeding values for those traits, were allocated in replicate groups to either High- or Low-nutrition treatments. By design, the supplementary feeding regime was the same for the High and Low genetic lines to ensure genetic differences were not confounded with management differences. Animal productivity results from the experiment were used as input data to evaluate the economic performance of the four genetic lines under the two nutritional treatments. Two methods were used; the first was a gross-margin calculation of income minus variable costs as AU$ per breeding cow for a 1000-cow herd; the second was a whole-farm linear programming model maximising the gross margin. Stocking rates were optimised by matching the energy requirements for the whole herd with the energy available from pasture and supplementary feed on a representative 700-ha farm. Using the two methods of calculating gross margin (per cow and optimised per hectare), including examination of sensitivity to changes in prices of cattle and supplementary feed, the present study demonstrated that genetically leaner cows due to selection of low fat or low residual feed intake, had gross margins superior to those of genetically fatter cows. They generated more income by selling more liveweight due to heavier weights and higher stocking rates. The results are affected by the management system utilised and some confounding with growth (leaner genetic lines had higher growth estimated breeding values), but will assist producers to make more informed decisions about how to manage animal breeding and nutritional interactions.

This study measured forage biomass production, diet quality, cattle liveweight gain, and economic performance of six forage types at 21 sites across 12 commercial beef cattle properties in the Fitzroy River catchment of Queensland during 2011–2014 (28 annual datasets in total). The forages were annual forage crops (oats (Avena sativa), sorghum (Sorghum spp.) and lablab (Lablab purpureus)), sown perennial legume-grass pastures (leucaena-grass (Leucaena leucocephala spp. glabrata + perennial, tropical grass (C4) species) and butterfly pea-grass (Clitoria ternatea + perennial, C4, grass species)), and perennial, C4, grass pastures. The sown forages resulted in 1.2–2.6 times the annual cattle liveweight gain per ha than perennial grass pastures. Annual cattle liveweight gain per ha, forage establishment and management costs, and cattle price margin (sale price less purchase price, $/kg liveweight) all influenced gross margin, however, none was an overriding factor. The average gross margins ($/ha.annum) calculated using contractor rates, ranked from highest to lowest, were: leucaena-grass pastures, 181; butterfly pea-grass pastures, 140; oats, 102; perennial grass, 96; sorghum, 24; and lablab, 18. It was concluded that the tendency towards greater average gross margins for perennial legume-grass pastures than for annual forage crops or perennial grass pastures was the result of the combined effects of lower average forage costs and high cattle productivity.

Previous studies of greenhouse gas emissions (GHGE) from beef production systems in northern Australia have been based on models of ‘steady-state’ herd structures that do not take into account the considerable inter-annual variation in liveweight gain, reproduction and mortality rates that occurs due to seasonal conditions. Nor do they consider the implications of flexible stocking strategies designed to adapt these production systems to the highly variable climate. The aim of the present study was to quantify the variation in total GHGE (t CO2e) and GHGE intensity (t CO2e/t liveweight sold) for the beef industry in northern Australia when variability in these factors was considered. A combined GRASP–Enterprise modelling platform was used to simulate a breeding–finishing beef cattle property in the Burdekin River region of northern Queensland, using historical climate data from 1982–2011. GHGE was calculated using the method of Australian National Greenhouse Gas Inventory. Five different stocking-rate strategies were simulated with fixed stocking strategies at moderate and high rates, and three flexible stocking strategies where the stocking rate was adjusted annually by up to 5%, 10% or 20%, according to pasture available at the end of the growing season. Variation in total annual GHGE was lowest in the ‘fixed moderate’ (~9.5 ha/adult equivalent (AE)) stocking strategy, ranging from 3799 to 4471 t CO2e, and highest in the ‘fixed high’ strategy (~5.9 ha/AE), which ranged from 3771 to 7636 t CO2e. The ‘fixed moderate’ strategy had the least variation in GHGE intensity (15.7–19.4 t CO2e/t liveweight sold), while the ‘flexible 20’ strategy (up to 20% annual change in AE) had the largest range (10.5–40.8 t CO2e/t liveweight sold). Across the five stocking strategies, the ‘fixed moderate’ stocking-rate strategy had the highest simulated perennial grass percentage and pasture growth, highest average rate of liveweight gain (121 kg/steer), highest average branding percentage (74%) and lowest average breeding-cow mortality rate (3.9%), resulting in the lowest average GHGE intensity (16.9 t CO2e/t liveweight sold). The ‘fixed high’ stocking rate strategy (~5.9 ha/AE) performed the poorest in each of these measures, while the three flexible stocking strategies were intermediate. The ‘fixed moderate’ stocking strategy also yielded the highest average gross margin per AE carried and per hectare. These results highlight the importance of considering the influence of climate variability on stocking-rate management strategies and herd performance when estimating GHGE. The results also support a body of previous work that has recommended the adoption of moderate stocking strategies to enhance the profitability and ecological stability of beef production systems in northern Australia.

Grazing enterprises on the Central Tablelands of New South Wales employ a range of different strategies to manage temperate native grassland pastures common in the high rainfall zone of southern Australia. This paper uses a stochastic whole-farm simulation modelling approach to assess the impact of grazing system and stocking rate (SR) on the long-term profitability of a representative case-study enterprise. In particular, the impact of infrastructure costs, debt and downside risk, on whole-farm performance are examined over a 10-year planning horizon. In total, 12 different strategies were modelled under both price and climate risk, with a matrix of three paddock systems (1-paddock, 4-paddock and 20-paddock rotations) and four stocking rates (SR of 3, 4.2, 5.3 and 7 ewes/ha). Profitability was primarily driven by SR. In general, higher SR increased total farm output and annual profits under favourable conditions, although they were also associated with higher costs and greater downside risk in poor seasons, which in turn was magnified by the compounding effect of accumulating debt over time. When SR increased above 4.2 ewes/ha, it had a negative impact on lamb sale weights, resulting in lower prices due to lambs not meeting the ≥40-kg liveweight specification. Although this was offset by increased whole-farm production volumes at 5.3 ewes/ha, declines in profitability occurred at 7 ewes/ha as a result of significant increases in supplement feeding costs, and lambs not meeting sale weight specifications. The analytical scale of the analysis also had an impact on the relative profitability between alternative treatments. When assessed using a partial measure of economic analysis (gross margin per ha), there was little difference between paddock system treatments at the same SR. When the cost of additional fencing and water infrastructure were accounted for at the whole-farm analytical scale, the 20 paddock system was markedly less profitable than the 1- and 4-paddock rotations. This highlights the need for assessing production systems at an appropriate analytical and temporal scale to better understand the relationship between the key drivers of long-term profitability and risk. Overall there were relatively small differences in whole-farm performance between the four best performing strategies in this study. Given the trade-offs between profitability, downside risk, ground cover and feedbase sustainability, the lower risk 1- and 4-paddock systems with a SR of 4.2 ewes/ha are proposed as being optimal.

Our objective was to evaluate the productive and economic performances of bulls fed increasing levels of sugarcane tops, as a substitute for sugarcane. Sixteen, 24-month-old, Nellore bulls (initial bodyweight = 360 ± 14.7 kg) were kept in a feedlot for 84 days, receiving a high-concentrate diet (80 : 20 concentrate : roughage ratio). Four levels of substitution were evaluated: T0 = no addition of sugarcane tops; T33 = 33% substitution; T66 = 66% substitution; and T100 = total substitution of sugarcane by sugarcane tops. Dry matter, organic matter, crude protein and neutral detergent fibre intake, bodyweight gain, feed conversion and feed efficiency were evaluated as productive performance parameters, and as economic indicators, total revenue, total operating expenses, gross margin, and net margin. No effect (P ≥ 0.66) of diet was found for the studied variables. Average values of total bodyweight gain, average daily gain, feed conversion, and feed efficiency were 102 ± 10.0 kg/animal, 1.2 ± 0.12 kg/day, 8.6 ± 0.72 and 0.12 ± 0.010, respectively. Unlike other treatments, the T100 net margin was positive, because of the lower cost of acquiring sugarcane tops compared with sugarcane. Partial or total substitution of sugarcane by sugarcane tops in high-concentrate diets did not affect performance of feedlot bulls, but total substitution reduced production costs, with positive net margin. We conclude that sugarcane tops can be utilised as a low-cost roughage source in diets for beef bulls.

Approximately 5% of Australian national greenhouse gas (GHG) emissions are derived from the northern beef industry. Improving the reproductive performance of cows has been identified as a key target for increasing profitability, and this higher efficiency is also likely to reduce the GHG emissions intensity of beef production. The effects of strategies to increase the fertility of breeding herds and earlier joining of heifers as yearlings were studied on two properties at Longreach and Boulia in western Queensland. The beef production, GHG emissions, emissions intensity and profitability were investigated and compared with typical management in the two regions. Overall weaning rates achieved on the two properties were 79% and 74% compared with typical herd weaning rates of 58% in both regions. Herds with high reproductive performance had GHG emissions intensities (t CO2-e t–1 liveweight sold) 28% and 22% lower than the typical herds at Longreach and Boulia, with most of the benefit from higher weaning rates. Farm gross margin analysis showed that it was more profitable, by $62 000 at Longreach and $38 000 at Boulia, to utilise higher reproductive performance to increase the amount of liveweight sold with the same number of adult equivalents compared with reducing the number of adult equivalents to maintain the same level of liveweight sold and claiming a carbon credit for lower farm emissions. These gains achieved at two case study properties which had different rainfall, country types, and property sizes suggest similar improvements can be made on-farm across the Mitchell Grass Downs bioregion of northern Australia.

Here we examine the concordance among emissions, production and gross margins of extensive beef farming systems by modelling a range of scenarios for herd management, animal genotype and pasture nutritive quality. We based our simulations on a case-study farm in central Queensland, Australia, and studied the influence of interventions designed for emissions mitigation, increasing productivity, or increasing gross margin. Interventions included replacing urea supplementation with nitrate, finishing cattle on the perennial forage leucaena (L), herd structure optimisation (HO), higher female fecundity (HF), and a leucaena finishing enterprise that had net farm emissions equal to the baseline (leucaena equal emissions; LEE). The HO intervention reduced the ratio of breeding cows relative to steers and unmated heifers, and lowered the ratio of costs to net cattle sales. Gross margin of the baseline, nitrate, L, LEE, HO and HF scenarios were AU$146 000, AU$91 000, AU$153 000, AU$170 000, AU$204 000 and AU$216 000, respectively. Enterprises with early joining of maiden heifers as well as HO and HF further increased gross margin (AU$323 000), while systems incorporating all compatible interventions (HO, HF, early joining, LEE) had a gross margin of AU$315 000. We showed that interventions that increase liveweight turnoff while maintaining net farm emissions resulted in higher gross margins than did interventions that maintained liveweight production and reduced net emissions. A key insight of this work was that the relationship between emissions intensity (emissions per unit liveweight production) or liveweight turnoff with gross margin were negative and positive, respectively, but only when combinations of (compatible) interventions were included in the dataset. For example, herd optimisation by reducing the number of breeding cows and increasing the number of sale animals increased gross margin by 40%, but this intervention had little effect on liveweight turnoff and emissions intensity. However, when herd optimisation was combined with other interventions that increased production, gross margins increased and emissions intensity declined. This is a fortuitous outcome, since it implies that imposing more interventions with the potential to profitably enhance liveweight turnoff allows a greater reduction in emissions intensity, but only when each intervention works synergistically with those already in place.

A bio-economic modelling framework (GRASP-ENTERPRISE) was used to assess the implications of retaining woody regrowth for carbon sequestration on a case study beef grazing property in northern Australia. Five carbon farming scenarios, ranging from 0% to 100% of the property regrowth retained for carbon sequestration, were simulated over a 20-year period (1993–2012). Dedicating regrowth on the property for carbon sequestration reduced pasture (up to 40%) and herd productivity (up to 20%), and resulted in financial losses (up to 24% reduction in total gross margin). A net carbon income (income after grazing management expenses are removed) of $2–4 per t CO2-e was required to offset economic losses of retaining regrowth on a moderately productive (~8 ha adult equivalent–1) property where income was from the sale of weaners. A higher opportunity cost ($ t–1 CO2-e) of retaining woody regrowth is likely for feeder steer or finishing operations, with improved cattle prices, and where the substantial transaction and reporting costs are included. Although uncertainty remains around the price received for carbon farming activities, this study demonstrated that a conservatively stocked breeding operation can achieve positive production, environmental and economic outcomes, including net carbon stock. This study was based on a beef enterprise in central Queensland’s grazing lands, however, the approach and learnings are expected to be applicable across northern Australia where regrowth is present.

Applying a bio-economic whole-farm model, we assess the impact of price and weather risk as well as different risk-management strategies on the variability of the gross margin in Swiss suckler cow production. For instance, flexible adjustment of fodder composition, feed stocks, or land use as well as gross margin insurance are considered. Our results show that assuming moderate risk aversion farms’ gross margin variability is rather high, with a coefficient of variation of gross margin ranging from 19 to 21%. Accounting for on-farm risk-management strategies we find that gross margin variability can be reduced significantly, causing only low reductions of average gross margin levels. We find that the use of maize as a switch crop and a market for the trade of roughage are the most efficient risk-management strategies. Our results also indicate that gross margin insurance is not attractive for farmers. Thus in particular promoting better access to markets for feedstuffs provides a valuable opportunity for farmers to manage gross margin risks.

Continuous-cropping systems based on no-till and crop residue retention have been widely adopted across the low-rainfall cereal belt in southern Australia in the last decade to manage climate risk and wind erosion. This paper reports on two long-term field experiments that were established in the late 1990s on texturally different soil types at a time of uncertainty about the profitability of continuous-cropping rotations in low-rainfall environments. Continuous-cereal systems significantly outyielded the traditional pasture–wheat systems in five of the 11 seasons at Waikerie (light-textured soil), resulting in a cumulative gross margin of AU$1600 ha–1 after the initial eight seasons, almost double that of the other treatments. All rotation systems at Kerribee (loam-textured soil) performed poorly, with only the 2003 season producing yields close to 3 t ha–1 and no profit achieved in the years 2004–08. For low-rainfall environments, the success of a higher input cropping system largely depends on the ability to offset the losses in poor seasons by capturing greater benefits from good seasons; therefore, strategies to manage climatic risk are paramount. Fallow efficiency, or the efficiency with which rainfall was stored during the period between crops, averaged 17% at Kerribee and 30% at Waikerie, also indicating that soil texture strongly influences soil evaporation. A ‘responsive’ strategy of continuous cereal with the occasional, high-value ‘break crop’ when seasonal conditions are optimal is considered superior to fixed or pasture–fallow rotations for controlling grass, disease or nutritional issues.

Month of joining and lamb sale strategy influence both the quantity and so value of lamb produced, and the feed required, so are important management decisions contributing to the profitability of sheep systems. Simulation modelling was used to evaluate the impact on gross margins of three lamb sale strategies for different months of joining and varying stocking rates. A flock of purchased Merino ewes producing crossbred lambs in southern Australia was modelled between 1971 and 2011. April joining produced higher gross margins than November or January only if the number of ewes per hectare was increased to potential carrying capacity. At the optimum stocking rate for each month of joining, three sale policies – a flexible lamb sale policy (where lambs were sold depending on seasonal conditions); selling lambs in December; or selling at 45-kg liveweight, all produced a similar mean gross margin, but the feed resources required were least using the flexible strategy (April-joined mean 195 ± 253 s.d. kg/ha for flexible compared with 219 ± 270 kg/ha if selling December or 1085 ± 459 kg/ha if sold at 45 kg). Mean gross margin differed between sale strategies by up to AU$66/ha if the optimal stocking rate was not used. These results suggest that the most advantageous lamb sale strategy will vary with both month of joining and stocking rate used, and should be considered when optimising sheep management systems.

Slow pasture growth rates during winter limit the potential gross margins from autumn and early winter lambing in southern New South Wales (NSW) by limiting stocking rates and/or increasing supplementary feed requirements. Dual-purpose crops can reduce the winter feed gap in mixed-farming systems by increasing the available feed in winter. The simulation software AusFarm was used to model a mixed-farming system at Wagga Wagga with Merino ewes joined to terminal sires and grazing lucerne-subterranean clover pasture over a 41-year period. A paddock of dual-purpose wheat was then added to the system, and ewes were allowed to graze the wheat crop when feed on offer reached 850 kg DM/ha and before GS31. Weaned lambs were sold after late August if lamb growth rates fell below 20 g/head.day, mean lamb weight reached 45 kg or production feeding of lambs was required. Lambing in June resulted in the highest median gross margin whether or not ewes were able to graze the wheat crop during winter. Grazing of a dual-purpose wheat crop resulted in greater proportional increases in gross margins as stocking rate was increased, increased lamb production and reduced supplementary feeding costs, and reduced interannual variability in gross margin returns.

The aim of the study was to estimate the payback period of rangeland improvement investments made under the coordination of the Eastern Anatolia Agricultural Research Institute (EAARI) in the Eastern Anatolia region, Turkey. Farm data were collected from randomly selected rangeland-dependent dairy cattle farms through face-to-face interviews, which resulted in 99 completed questionnaires. Additionally, the data for rangeland improvement studies were obtained from the EAARI. The villages of study were selected from those for which rangeland condition had been determined previously. The data collected by structured questionnaires were for the 2004–05 production year. The farms were studied under three farm size groups of 0–12, 12.1–25 and 25+ ha. Gross margins were calculated for each studied farm. In the analysis of the data, stepwise regression, multiple linear regression and descriptive statistical methods were used. Of the 17 variables considered, only four variables entered to the log-linear livestock gross margin model. These were the type of building used by livestock in winter, cattle and sheep numbers and rangeland condition. Using estimates of the average values of the unit costs of rangeland improvement and additional incomes due to the improvements, it was estimated that on average each Turkish lira invested in rangeland improvement studies could be amortised in three grazing seasons.

On the New South Wales Northern Tablelands, sheep, wool and beef cattle production account for most agricultural output. The industries have been challenged in recent years by environmental and economic factors and are therefore looking for modified or alternative livestock management systems that are capable of sustaining profitability. The Cicerone Project aimed to address these issues by comparing three different grazing and pasture improvement systems. Some recent livestock industry analyses have been based on gross margins which do not include overhead costs. This is an important limitation; economic analysis needs to report key whole-farm business performance measures since overhead costs can differ significantly between livestock management systems. A representative farm approach was used to compare the profitability of the three different livestock management systems. Commercial-scale whole-farm and cash flow analyses over a 5-year period were used to evaluate profitability. No particular system could be recommended to graziers because the test period was not sufficiently representative of the long-term climate to make an adequate assessment about their long-term profitability. Nevertheless, it is apparent that whole-farm level budgets are essential for comparing the overall profitability of different livestock management systems. It is concluded that analysts, consultants and graziers should use whole-farm and cash flow analyses to gauge profitability of different livestock management systems particularly where sustainability issues are important.

Several grazing strategies are recommended to manage sustainably for rainfall variability in northern Australia, but there is little objective data on their profitability relative to less sustainable management systems such as heavy stocking. In 1997, a large cattle grazing trial was initiated in northern Queensland to quantify the relative performance of a range of grazing strategies in a variable climate. These strategies were (i) moderate stocking (MSR) stocked at the calculated long-term carrying capacity (LTCC), (ii) heavy stocking (HSR) at twice LTCC, (iii) rotational wet-season spelling (R/Spell) at 1.5 LTCC, (iv) variable stocking (VAR), with stocking rates adjusted in May based on available forage and (v) a southern oscillation index (SOI)-variable strategy, with stocking rates adjusted in November based on available forage and SOI-based seasonal forecasts. Rainfall varied over the 12-year trial period, with sequences of dry and wet years. Gross margins (GM) in the HSR were initially high but collapsed in drier years due to high costs and reduced product value. GMs only recovered in later years with a reduced stocking rate and increased rainfall. The VAR and SOI were also initially very profitable, but GMs plunged as rainfall declined due to reduced animal performance and the sale of poor-condition cattle. This sharp cut in stocking rates nevertheless allowed GMs to recover well in subsequent years. In the MSR, GMs remained relatively constant across most years due to low costs and a higher product value. The R/Spell also performed relatively well despite being compromised by an ill-timed fire, drought and the subsequent sale of poor-condition cattle. Net present value (NPV) after 12 years was highest in the VAR ($11 962/100 ha), followed by the MSR ($11 873/100 ha), the SOI ($11 167/100 ha) and the R/Spell ($10 665/100 ha). NPV was by far the lowest in the HSR ($6930/100 ha). Profitability also varied the most in the HSR, with a negative GM in 6 of the 12 years. Incorporating the costs of natural resource decline would further reinforce the case against heavy stocking. These results challenge the assumption that sustainable management in a variable environment is unprofitable.

In the absence of financial information on Australian mohair enterprises we aimed to determine the gross margins (per dry sheep equivalent, DSE) and their relationships with farm inputs, productivity and mohair quality in Australian mohair enterprises. Using established Victorian Farm and Sheep Monitor Project protocols we collected data for the financial years 2004–05, 2005–06 and 2006–07 from farmers in south-eastern Australia and made comparisons with data from wool enterprises of similar farm area. Over 3 years the financial returns from mohair exceeded that from wool in terms of $/DSE ($23.0 v. 11.3) and $/ha ($132 v. $116). This result was achieved despite the mohair enterprises grazing their goats far less intensively compared with the grazing intensity of sheep (5.9 v. 10.3–11.1 DSE/ha) and by using far less phosphate fertiliser than used in the wool enterprises (2.2 v. 4.6–6.1 kg P/ha). These differences were counterbalanced by higher prices for mohair compared with fine wool ($13.15/kg v. $8.35/kg clean fibre). Gross margin for the mohair enterprise did not increase as stocking rate increased. Income from mohair sales declined as the proportion of does in the flock increased. Increasing the proportion of does in the flock was associated with a decline in the average price of mohair ($16/kg greasy at 42% does to $8/kg greasy at 83% does in the flock). This decline was closely associated with the increasing proportion of the total amount of mohair coarser than 34.0 µm (either fine hair or hair) plus stained mohair. The variation in profitability between farms indicates significant scope for many mohair enterprises to increase profit. A focus on producing finer quality mohair will increase mohair profitability.

Empirical and simulation results from three crop rotations incorporating cereals, pulses and nitrogen (N) fertiliser application were examined over 4 years in a subtropical environment, central Queensland, Australia. The hypothesis was that pulse crops in rotation with cereals would be a viable alternative to applying N fertilisers and would improve farm business economic performance provided the yield potential of pulses were not compromised by planting into very low soil water situations. Empirical data and simulations with the Agricultural Production Systems Simulator model were used to give insights into the N contribution, yield benefit to cereals and overall economic performance of the inclusion of pulses into the rotation. The field trial rotations included: rotation 1: sorghum and wheat in an opportunity crop rotation (called cereals-only), rotation 2; cereals grown following a fallow with a pulse crop immediately after (called cereal double-cropped pulse) and rotation 3, pulses grown following a fallow with a cereal crop immediately after (called pulse double-cropped cereal). Empirical and simulated results indicated that the cereal double-cropped pulse rotation produced the highest average annual gross margins using prices at that time. In the simulations, when pulse crops were included in the rotation, no additional N fertiliser was required and the lowest chance of negative gross margins was obtained. The cereal double-cropped pulse rotation produced the largest trial and simulated gross margins. The pulse double-cropped cereal rotation produced greater gross margins than the N-deficient cereals-only rotation but significantly lower than the cereal double-cropped pulse rotation. Simulations indicated that the cereals-only rotation could be made profitable when the soil was ‘topped-up’ to 100 kg available N/ha before planting, or by 40 kg N/ha to each cereal crop. Chickpea and mungbean contributed an average of 35 and 29 kg N/ha, respectively, in the field trial. A minimum of 100 mm of the stored soil water at planting was needed to reduce the risk of negative returns. By planting only when the soil contained adequate water, the cereal double-cropped pulse rotation may provide a valuable supplement to farm income while simultaneously reducing the need for N fertilisers on the cereals. Alternatively, in a rotation with cereals only, modest amounts of fertiliser N will maintain profitability with minimal levels of financial risk.

Grazing crop stubbles affects soil structure, groundcover, and the productivity of subsequent crops, but the cost of this practice is highly variable and not easily compared against the value of feed provided to livestock. To compare with and without grazing stubbles in terms of whole-farm profit and water-use efficiency we created a mixed enterprise farm model using the Agricultural Production Systems Simulator and GRAZPLAN biophysical simulation submodels, and the Model of Integrated Dryland Agricultural System linear programming model. We hypothesised that grazing crop stubbles would increase farm profit by an amount equivalent to the value of the metabolisable energy (ME) consumed by sheep when they grazed the crop stubbles. Representative mixed farms where sheep were or were not allowed to graze crop stubbles were compared for two locations in the wheatbelt of Western Australia (Cunderdin and Geraldton) at two stocking rates. Across locations and stocking rates, the estimated value of the ME intake from crop stubbles was 2.2 times the increase in farm gross margin when stubble grazing was allowed. Contributing to this difference was that stubble grazing provided a less flexible feed source than supplementary feeding and in the absence of adjustments in stocking rates sheep tended to utilise more of the annual and permanent pastures when stubble grazing was not permitted. Therefore, the value of grazing crop stubbles to the profitability of the farm enterprise was overestimated by the ME value of the intake. Owing to reduced consumption of supplementary feed by livestock, whole-farm water-use efficiency of protein production was increased by 15% when grazing of crop stubbles was permitted. This simulation study shows that the value of grazing crop stubbles cannot be predicted well using energy intake from stubble grazing or reduced supplementary feeding costs.

Phosphorus (P) fertilisers are one of the key tools available for increasing pasture production and the profitability of grazing enterprises. However, recent rapid changes in fertiliser price have increased the importance of developing optimal management strategies for applying P fertiliser and setting stocking rates. We applied a novel combination of process-based grazing systems modelling and randomised cash flow analyses to examine how changes in fertiliser price affect optimal fertiliser application rates and stocking rates for sheep grazing systems in south-eastern Australia, simultaneously taking into account long-term economic viability and environmental sustainability. We used ‘GrassGro’, a grazing systems decision support tool, to simulate three sheep enterprise types (Merino wethers, Merino ewes, crossbred ewes) at two locations (Hamilton, Victoria; Bookham, New South Wales). Gross margins from each year simulated in GrassGro (1966–2007) were randomised 500 times and input to a cash flow analysis that identified the financially optimal stocking rate for a range of fertiliser applications and the financial risk frontiers (combinations of stocking rate and fertiliser input for which the enterprise becomes financially unviable). For all enterprises examined at both locations, the optimal combinations of stocking rate and fertiliser application rate did not vary markedly as fertiliser price changed. Regardless of enterprise type or location, the fertiliser application rate at which the highest gross margins were achieved provided the greatest range of stocking rates that were both financially viable and environmentally sustainable. Increases in fertiliser price reduced the combinations of stocking rate and fertiliser application rate that were viable in the long term, emphasising the importance of well informed grazing management decisions.

The Grain & Graze Whole-Farm Model was developed as a simple modelling tool to identify better strategies to improve the income of farmers and overcome grassland degradation. Using information on farm structure, crop and forage production systems, livestock production systems and variable costs involved in all enterprises, maximum whole-farm gross margins are obtained for an optimum or a prescribed mix of enterprises. The incorporation of production systems for different rainfall scenarios enables climatic risks and water use efficiencies of different enterprises to be investigated. Model simulations demonstrated the potential improvements that could be achieved in dollar water use efficiency ($WUE), by changes in management and/or changes in enterprise. The design of the model makes it a valuable tool for evaluating new systems, as it easy to develop new crop, pasture and livestock systems. Innovative farming systems such as pasture cropping and alley farming are included in the model.

Pasture degradation, particularly that attributable to overgrazing, is a significant problem across the northern Australian rangelands. Although grazing studies have identified the scope for wet season resting strategies to be used to rehabilitate degraded pastures, the economic outcome of these strategies has not been extensively demonstrated. An exploratory study of the prospective economic value of wet season resting is presented using an economic simulation model of a 28 000 ha beef enterprise located in the Charters Towers region of north-eastern Australia to explore seven hypothetical scenarios centred on the projected performance of a wet season resting strategy. A series of 20-year simulations for a range of pasture recovery profiles, stocking capacity, animal productivity responses, beef prices and agistment options are compared with a baseline scenario of taking no action. Estimates of the net present value of the 20-year difference in total enterprise gross margins between the various resting options and the ‘do nothing’ option identify that wet season resting can offer a positive economic return for the range of scenarios examined, although this is contingent on the assumptions that are made concerning the trajectories of change in carrying capacity and animal productivity. Some implications for management and policy making to support the practical implementation of wet season resting strategies are discussed.

An experiment was conducted at the Grafton Agricultural Research Station on the northern coast of New South Wales whereby low and high pasture nutritional systems were imposed on a herd of Hereford cows during pregnancy and from birth to weaning in a factorial design. Offspring representing extremes of growth to birth and/or weaning were then selected for study of long-term consequences of growth early in life. Implications of the nutritional treatments of cows on subsequent weaning rates were also tested with data from previous studies. The extent to which these extreme maternal nutritional and offspring growth scenarios affected herd profitability was tested with the Beef-N-Omics decision support package. For the representative cattle enterprise modelled, gross margin per hectare ranged from $A114 to $A132. In all cases, the gross margin for those groups with fetal growth based on a higher level of nutrition exceeded that of their peers on a lower level of nutrition. It is more profitable for cows and calves to have access to a high standard of nutrition during pregnancy and up to weaning than for them to have access only to a poor standard of nutrition. Incorporating differential weaning rates following maternal nutritional treatments reduced gross margins per hectare by up to 30%. On average, a 1% reduction in weaning rate resulted in a 4.5% reduction in gross margin. Restricted cow–calf nutrition affects the future cow fertility, as well as the current calf progeny, economically.

The ‘Regional Combinations’ project and its biophysical outcomes have been described in several other papers in this special edition. The information provided in these papers allows an evaluation of the most profitable beef cattle production systems across different environments in southern Australia. In this paper, the focus is on the New South Wales experimental site where the trial animals were finished in a feedlot. The data identified liveweight gain as the biggest driver of profitability of production. Between growth treatments, there was a large difference in the gross margins before feedlot entry between the ‘fast’ and ‘slow’ treatments favouring the fast-grown animals, even after accounting for the higher cost of producing pasture capable of sustaining faster growth. However, the slow growth treatments consistently outperformed the fast growth treatments in the feedlot. In terms of breeds, the European breed types consistently outperformed the Wagyu breeds. There were no time-of-calving experiments in New South Wales.

Two experiments yielded practical recommendations on design of cage equipment (mats and nest boxes) that can potentially improve the welfare and productivity of breeding does. The results show that, in the environment experienced by the experimental rabbits, sore hocks (pododermatitis) can be reduced in breeding does from an incidence of 4% down to less than 1%, by the provision of suitable pressure mats. The difference between the highest and lowest performing nest boxes, in terms of number of kittens weaned, translates into a difference in enterprise gross margins of A$52.35 per doe per annum, or an increase of 36% in profit from the use of the best performing nest box compared with the worst. Farmers can use the results as a guide to choosing or constructing nest box equipment, and should be encouraged to objectively compare different designs under their own environmental conditions.

Inadequate ground cover because of over-grazing of pastures, fallowing and stubble burning or excessive cultivation exposes land to degradation, yet maintaining cover can constrain productivity. We used long-term simulation analysis to investigate the impact of modifying stock and crop management practices on the trade-off between farm productivity (grain, meat and wool) and ground cover levels. Management of mixed farms at five locations (426–657 mm mean annual rainfall) in the Murrumbidgee catchment of New South Wales was represented for simulated farms that included permanent pastures, crop–pasture rotations, and a meat/wool sheep enterprise. Locations varied in their stocking rate, soil characteristics and proportion of land area allocated to various crops and pastures. At each location we investigated the impact on ground cover and farm productivity of (1) retention of wheat stubble, (2) altering stocking rate (up to ±25%) and (3) moving stock elsewhere on the farm when the mean value of ground cover fell below a given threshold (50, 60, 70, 80 or 90%) for either, all pasture on the farm or an individual paddock. The analysis showed that seasonal conditions were the dominant effect on the mean farm cover (mean range 64–98%); cover fell as low as 43–57% in severe droughts, depending on location. Retention of wheat stubble increased long-term mean cover by 1–4%, with little impact on grain yield. Altering stocking rate had the largest impact on cover at all locations (up to 4%), although there was a trade-off with productivity. Maintaining a constant stocking rate, although moving stock within the farm, had a small, positive effect on the whole-farm cover, although it reduced gross margin because of the cost of supplementary feeding. Confining stock to a 3 ha feeding lot was the most effective strategy for maintaining ground cover and minimising financial loss. Our analysis did not account for the benefits of maintaining high levels of ground cover on the long-term productive capacity of the farm through on-farm or off-farm environmental benefits. We conclude that ground cover is dominated by climatic effects, and that within the range of stock management practices examined in the present study, practices that increase minimum cover levels also reduce farm productivity. Reducing total stocking rate, or removing stock from the farm during periods of low cover, will have the greatest impact on maintaining cover, although it will reduce whole-farm profit.

Decisions about fire management on pastoral properties are often made with little empirical knowledge. Proper accounting of the interactions between land, pasture, trees and livestock within the context of climatic variability and market conditions is required in order to assess financial implications of alternative fire management regimes. The present paper aims to facilitate such accounting through the development of a manager-driven decision-support tool. This approach is needed to account for variable property conditions and to provide direction towards considering optimal practices among a vast array of potential activities. The tool is an interactive model, developed for a hypothetical property, which analyses the costs and benefits of a baseline (no fires) against a historically based probability of wildfire overlaid by four alternative fire management regimes, representing cumulatively increasing levels of fire management intensity. These are: Regime 1, no action taken to prevent or stop wildfires; Regime 2, fire suppression (reactive fighting of wildfire); Regime 3, Regime 2 plus prevention (early dry-season burning); and Regime 4, Regime 3 combined with storm-burning (burning soon after the first wet-season storm). The model, which shows that fire and fire management have significant influences on the gross margin of Cape York Peninsula cattle properties, can be used as a decision-support tool in developing fire management strategies for individual properties. Specific fire management recommendations follow, together with the identification of potential areas of future work needed to facilitate use of the tool by clients.

The traditional slaughter ostrich production system evolved mainly around two aspects: producing the optimum skin size and attaining the ideal shape of follicle on the skin. Over time the practice of slaughtering ostriches at 14 months of age proved to be the ideal system and became the standard in the ostrich industry. With a gradual increase in demand for ostrich meat in the past decade, the meat yielded by a 14-month-old bird provided additional income to the producer. However, the cost of feed can affect profitability and, especially so, for a production system over a 14-month period. In addition to increasing feed costs, evidence exists of an increasing risk of skin damage over long production periods, affecting income negatively. A study at the Kromme Rhee experimental farm near Stellenbosch in South Africa investigated slaughter age regimes at 8.5 months, 10.5 months, 12.5 months, 14.5 months and 16.5 months. Data on feed intake and yields of cold carcass, crust skin size, skin grade and total feathers revealed significant differences (P

Lucerne phase farming has been suggested as a way of reducing deep drainage in the cereal belt of southern Australia. It is based on the concept that lucerne (Medicago sativa L.), a perennial pasture with a deep root system, creates a soil water storage buffer below the root zone of the annual crops, which gradually refills during the subsequent cropping phase, temporarily reducing the risk of deep drainage. The rate of refilling is variable because it is affected by the amount and distribution of rainfall as well as management of the crop and the summer fallow. There is, therefore, uncertainty about the optimum phase durations that will maximise the effect of the lucerne phase. Computer simulations were applied to evaluate the use of a soil water measurement below the root zone of annual crops to schedule the phase changes, referred to as tactical phase farming. The results confirmed that phase farming reduced average annual deep drainage significantly, but at the cost of lower average annual gross margin. In most cases, tactical phase farming improved the trade-off between deep drainage and gross margin relative to fixed duration phases; for a given amount of average annual deep drainage the average annual gross margin was larger, and for a given gross margin the drainage was smaller. The benefits of tactical phase systems were greatest in soils with a large available water-holding capacity and when the variability of the refilling rate was large. Overall, however, the benefits of the tactical approach relative to fixed phase systems were small.

The gross margin returns of first cross ewes by different sires have been evaluated on an equivalent carrying capacity basis by taking account of the feed requirements for the ewes and lambs and their varying performance and requirements throughout the annual production cycle. The study involved 2846 crossbred ewe progeny generated by 91 maternal sires from several breeds at 3 sites over 3 years including genetic links. The ewes were joined to terminal sire rams for 3 years and 8878 of their second cross lamb carcasses were included in the evaluation. The annual gross margin (A$GM) for individual ewes included income from lamb carcasses (with fat and weight discounts), lamb skins and ewe wool production, and costs for management and marketing. Individual feed requirements were calculated for ewe maintenance, gestation, lactation and lamb growth (pre- and post-weaning) and $GM was expressed on a dry sheep equivalent (dse) basis. Sire breed was not significant with a range of $5.28 GM/dse between sire breed means. There was a considerably greater range of up to $15 GM/dse among most of the sire ewe progeny groups within breeds and overlap among all sire breeds. Lamb turnoff rate was the major profit driver with lamb growth rate and carcass fat levels also contributing. The opportunities for genetic improvement in profitability of lamb enterprises are discussed.

Long-run rotational gross margins were calculated with yields derived from biophysical simulations in a crop simulation model over a period of 100 years and prices simulated in @Risk based on subjective triangular price distributions elicited from the Jimbour Plain farmer group. Rotations included chickpeas, cotton, lucerne, sorghum, wheat and different lengths of fallow. The aim was to assess the profitability of rotations with and without lucerne. Output presented to the farmers included mean annual gross margins and distributions of gross margins with box and whisker plots found to be suitable. Mean–standard deviation and first- and second-degree stochastic dominance efficiency measures were also calculated. The paper outlines a method for combining biophysical and price simulations that can be understood by farmers. Including lucerne in the rotations improved some sustainability indicators but reduced profitability.

In the dryland cropping areas of southern Australia, at risk from dryland salinity, tree belts can improve water management by taking up water unused by crops, with the risk that crop yield will be reduced through competition. As there are few direct markets for tree products grown in the medium to low rainfall areas, the design of agroforestry systems becomes important in reducing the trade-off in crop yield. This study examined some factors that influence the trade-off between crop yield and deep-drainage control in order to develop design guidelines for medium to low rainfall agroforestry. Twenty-one sites in the grain-growing region of Western Australia and southern New South Wales were surveyed over 2 years for crop yields, tree leaf area index, and estimated recharge, providing data from 32 tree–crop interfaces on the relative influence of environmental factors and farming system characteristics on the trade-off between water management and crop yield. The factors most strongly correlated with higher yields were water-gaining sites, orientation that provided shelter from southerly to north-westerly (S, SW, W, NW) winds, and tree age (10 years), lighter soil types, and low rainfall (

A seeding rate aimed at establishing 45 plants/m2 has been the long-standing recommendation for lupin crops in Western Australia. However, contrary to recommendations, many farmers in low rainfall areas of the state use a seeding rate that results in densities as low as 25–30 plants/m2, claiming that these rates give more reliable yields. Current recommendations for optimal lupin seeding rates are based solely on maximisation of expected profit and risk preferences have not been considered. The present study tested the hypothesis that optimal lupin seeding rates are lower if the farmer is averse to risk. A risk analysis of lupin yields in response to seeding rates was conducted to determine whether optimal seeding rates are lower for farmers who are risk averse. The analysis was based on results from field trials from various locations in Western Australia in various years. Lupin yields were not less reliable at high seeding rates and therefore risk aversion does not materially reduce the optimal seeding rate. Farmers who used a seeding rate lower than the recommended rate forewent profit without lowering risk. In the low and medium rainfall areas, the average reduction in expected gross margin from using a suboptimum seeding rate (25–30 plants/m2) is AU$4–10/ha. Farmers in the high rainfall zone who aim for 25–30 plants/m2 could forego in excess of $30/ha, particularly in situations where high yields are possible.

A detailed study was undertaken on the pasture management practices of 146 producers across south-east Australia who participated in the Grassland’s Productivity Program (GPP) for 3 years between 1993 and 1997. The GPP was an extension program to assist wool producers to develop skills and gain confidence in their ability to manage more productive pastures on their farms. The program consisted of 50 farmer groups (200 farmers participating) spread across the 4 states of South Australia, southern New South Wales, Victoria and Tasmania. Each farmer established paired-paddocks on their own property to compare productive pastures with existing pastures. Productive pastures involve increased rates of fertiliser on pastures containing productive species, with stocking rate adjusted to consume available pasture. After 3 years of involvement in the GPP, there was a whole-farm increase in P fertiliser use by 6.3 kg P/ha, stocking rates by 2.6 dse/ha and annual pasture resowing by 0.9% of the farm, when averaged across the 146 participants. The participants were applying the productive pasture technology to almost a third of their properties in 1997 and the intention was to increase this to over half of their properties by 2000. The participants also changed farm management practices as the program effectively developed management skills. There were increases in the ability to assess pasture quality and quantity, livestock by weighing or physical assessment, and the ability to calculate per hectare production and per hectare gross margins. A high proportion of GPP participants were soil testing (0.92) and spring lambing (0.72) at the completion of the program. The results indicated that the adoption of productive pastures was generally consistent across south-east Australia for pastoral producers who participated in this program, although south-west Victorian and south-east South Australian GPP participants did increase whole-farm P application by more than GPP participants from outside that region. The widespread change in farming practice was attributed to the additive and interactive effect of the paired-paddock comparison, the guidance provided by the facilitator, the group interaction and the skills training. Each of these components of the paired-paddock model combined to form an effective agent for change to increase pasture productivity on these grazing properties.

In 1989, funding was provided to establish a large-scale (16-ha), long-term trial at Roseworthy campus. The trial aims to compare organic, biodynamic, integrated, and conventional broadacre farming systems for attributes of sustainability. It is overseen by a 13-member management committee comprising farmers with experience in each practice, agronomists, and soil scientists. Through the monitoring of indicators such as soil physical, chemical, and biological changes, product quality, economics, crop water usage, and energy requirements, the comparative advantages or disadvantages of each system are being evaluated in terms of productivity, profitability, and environmental sustainability. After 6 years, significant differences between systems are apparent in economic returns and soil available phosphorus (P) levels. The biodynamic treatment has the highest gross margins, followed by conventional, organic, and integrated. Conversely, available P levels on the biodynamic and organic treatments have declined 12 and 9%, respectively, since the start of the trial, while both the integrated and conventional treatments have increased soil P levels. In summary, it is too early in the trial to state categorically that any one system is more sustainable than another, although trends are now emerging. Weed management remains the main impediment to high production levels on the organic and biodynamic treatments, while input costs, variable yields, and low returns for grazed pastures are major constraints to high economic returns on the integrated and conventional systems.

A yearly management program for sheep in north-west Queensland has increased lambing percentage by > 20% compared with the district average. Greasy wool production of ewes over 4 years (1988-91) averaged 4.3 kg and wethers over 2 years (1990-91) averaged 5.7 kg. Managing sheep using this program increased wool production of the flock compared with the district average. The economic advantages of running breeding ewes or wethers was influenced by wool and sheep markets. During low wool prices ($2.82/kg net selling costs, 1990; $2.44/kg net selling costs, 1991) it was estimated that a 65% lamb weaning rate was needed for returns from the ewe and wether flock to be equal. Gross margins ($/DSE) for the ewe flock were 21.80, 17.07, 8.53 and 5.42 in years 1988, 1989, 1990, 1991 respectively and 5.82 and 5.01 for wethers in 1990 and 1991 respectively. Gross margin ($/DSE) of combined ewe and wether enterprises on properties representing the district, averaged 16.50, 14.20, 8.00 and 5.00 in years 1988, 1989, 1990 and 1991 respectively. The management program implemented at Toorak generated higher gross margins than the district average particularly during the years of higher wool prices.

On a representative farm in southern Australia, the efficiency of beef production might be improved l.8 fold through changes in management practices and adoption of new techniques to induce twinning and to regulate the sex of calves born. Twenty-six modelled production systems were examined. Two of the three most efficient systems (kg meat per unit feed energy) produced crossbred calves, used twinning to produce more calves and sold them at yearling (18 months) rather than weaner (7 months) age. The other most efficient system was a single-sex all-female production system. Profit was calculated for each production system using a gross margins analysis (that is, total income minus variable costs). This, with the pattern of feed supply, feed consumption and labour use for each production system, was used in a linear programming model of a 'representative farm' to determine the optimum (most profitable) beef production system. Two of the three most efficient production systems were also the most profitable, being more than twice as profitable as the simplest traditional systems. The high cost of producing single-sex calves in the all-female system made it, and other systems using sex-control, unprofitable. Cows in systems with high net returns were very productive, had a high efficiency of lean meat production, but also a high feed requirement which forced a reduction in the optimum (most profitable) number of cows for the representative farm. Good management and attention to feed supply will be essential for these more profitable systems to be sustainable.

Hereford, highgrade Simmental, and Belmont Red breeding and fattening herds were modelled using comparative productive traits established in a research program. These traits included survival and reproductive rates and liveweights of breeders grazing predominately improved pasture, and growth rates from weaning to sale under either pasture or pasture-plus-crop nutritional regimes. It was assumed that steers were targeted to the grass-fed Japanese market, which required carcass weights of 280-380 kg. Net income was estimated by developing a hypothetical property capable of supporting 1000 adult equivalents and using best-bet estimates of the variable and fixed costs of production for each herd. Belmont Red model herds produced higher net income ($A58 800) than Hereford ($19 000) or highgrade Simmental ($8 000) herds under the pastureonly regime. When surplus heifers and steers had access to summer and winter crops as well as pasture, net income was Belmont Red $60 600, Hereford $34 400, and highgrade Simmental$20 400. The lower earning capacity of the Hereford than the Belmont Red was due to lower herd output; higher variable costs, mainly due to higher costs for bulls and for tick and dystocia control; and lower prices, due to a smaller proportion of cattle meeting preferred fat scores. The difference between the Hereford and highgrade Simmental herds was mainly due to price reductions for the highgrade Simmental slaughter cattle because of failure to meet preferred fat scores. Their large mature size and, hence, fewer numbers to make up 1000 adult equivalents also contributed.

A simulation model of a grazing enterprise was used to examine the economic risk associated with stocking rate decisions in the mulga lands. The model used historical daily rainfall records for Charleville (1890 - 1984) as input for determining annual pasture production. Stocking rates were set each year at the end of summer to utilize a portion of the available forage. Gross margins were determined for a total of six levels of pasture utilization (20% to 80%). The simulation results support the hypothesis that higher levels of pasture utilization lead to consistently lower pasture yields, and greater variability in income (high risk). To reduce risk, this simulation study suggests a more conservative use of the pasture. Optimum levels of pasture use therefore need to be determined; both from an individual graziers requirement to meet short term needs, and society's preference for long tern conservation of the pasture resource. This requires the ability to identify the direct benefits and costs of different levels of pasture use. This study has indicated the value of simulation in examining these costs and benefits.

The productivity and economics of annual land use systems were evaluated by studying beef steers, continuous grazing and spring feed conserved as silage. One treatment measured the production of steers grazing annual pasture continuously from weaning in December until slaughter 12 months later. In the other treatment, cattle grazed similar pasture from December until slaughter in July at 15 months of age but in autumn were fed silage made from the spring growth on the same area. There were 2 stocking rates (0.4 and 0.5 ha per steer) and 2 replicates of the 4 treatments; the experiment ran continuously for 3 years. In all years the pasture only system cost less and produced, on average, 100 kg more carcass per ha than did the silage system and at current values was more profitable. Only when autumn pasture growth was greater than normal did the profitability of the silage system approach the pasture only system. In both biological and economic terms the pasture only system was less variable than the silage system because of the buffering effect of consistently abundant spring pastures. In years of poor growth of pasture in autumn, the silage treatment did not achieve the objective of producing premium carcasses in July, owing to their low weight and fatness. There were wide variations among years in patterns of pasture growth, and hence gross margins. Gross margin analyses were most sensitive to changes in sale price of cattle and then to changes in the cost of making and feeding silage; they were least sensitive to interest rates.

On annual pasture, ewes lambing in autumn and young steers grazed separately each at five stocking rates, and grazed together in a ratio of 4 : 1 at each of three stocking rates. Gross margin per hectare (GMH) from the sheep was greatest at the heaviest stocking rate that could be carried safely without supplementary feed, and from steers was greatest at the heaviest stocking rate at which a high proportion of carcases were first-grade, even in a year of poor pasture. Maximum GMH from the steers was obtained at a lighter equivalent stocking rate than that required for maximum GMH from the sheep. When the sheep and steers grazed together at a stocking rate where first-grade steer carcases were produced consistently, the loss in potential sheep GMH from reducing the sheep stocking rate to this level was greater than the value of any benefit from mixed stocking. This finding is discussed in relation to results from another environment where no difference was found between sheep and cattle in the stocking rate required for maximum GMH.

A survey of management practices on wheat farms in northern New South Wales was carried out on 50 farms between 1983 and 1985 and was supplemented by a questionnaire mailed to 750 growers in 1985. Information was collected on crop rotation, tillage practice, fertiliser use and weed control practices. Data were collected from 1 paddock on each farm and included: wheat grain yield and quality, available soil water and nutrients at sowing, wild oat density, and incidence of soil-borne diseases. The 3-year average grain yield in survey paddocks was 2.2 t/ha. Multiple regression analysis was used to identify factors affecting grain yield and protein in 1985. Of the variation in wheat grain yield, 74% was explained by variation in available soil water at sowing, available soil nitrate at sowing, sowing date and wild oat density. Grain protein content declined with increasing available soil water and phosphate at sowing and with earlier sowing, but increased with available nitrate at sowing. Agronomic practices aimed at maximising wheat grain yield, in the presence of a deficiency ofavailable soil nitrate, are likely to result in a reduction of grain protein content. Likewise, responses to application of nitrogenous fertiliser are likely to be inversely related to available soil water at sowing. The mean gross margin for 1984 and 1985, based on $100/t of wheat grain, was $128. The mean gross margin for the least profitable 20% of paddocks was $37, and $253 for the top 20%. New varieties of wheat and herbicides were readily adopted by farmers. On the other hand, adoption of nitrogenous fertiliser use was slow, considering the widespread and long-standing deficiencies of nitrogen in cropping soils of the region. Crop rotation and tillage practices have changed only marginally since the late 1940s. The results of this survey indicate that the usefulness of soil testing for predicting fertiliser requirements could be improved by taking into account levels of available soil water, weed competition and sowing date and by using multiple regression analysis.

White Leghorn x Australorp crossbred pullets were either fed ad libitum or given restricted access to food from 8 to 20 weeks of age. Birds from each of these rearing treatments were thereafter distributed among five feeding regimes: ad libitum and four allowances representing reductions of 3, 6, 12 and 24 per cent of the food intake of the birds fed ad libitum throughout life. Biological and economic performance data were examined for the rearing period and for three periods of lay terminating at 66, 78 and 90 weeks of age. From 8 to 20 weeks of age the restrictively reared pullets ate 30.5 per cent less food, suffered 1.7 per cent higher mortality, cost 19 cents per bird less to rear and were 20.5 per cent lighter in weight at 20 weeks than the pullets fed ad libitum. Compared with ad libitum feeding, restricted feeding in the rearing period gave higher values for hen-housed egg production and hen-housed gross margin when food intake in lay was restricted by 0, 3 and 6 per cent, and lower values for these criteria when food intake in lay was restricted by 12 and 24 per cent. Birds whose food intake was restricted by 6 per cent in the laying period laid about 25 more eggs to 90 weeks of age than birds fed ad libitum in lay. Optimum slaughter time (age at which average gross margin per week was maximized) was at about week 90 for the ad libitum/12 per cent restriction and ad libitum/24 per cent restriction treatments, and between weeks 66 and 78 for all other treatments. The highest weekly average gross margin was achieved with the birds that were restrictively reared and restricted by 6 per cent throughout a laying period terminating at 78 weeks of age; at this stage their gross margin was $2.30 per bird higher than that of the birds fed ad libitum throughout life

From 1964-1969 wool production, liveweight, and wool quality traits were measured on Merino wethers stocked at rates ranging from 2 per acre (4.9 ha-1) to 8 per acre (19.8 ha-1) on plots receiving 50, 150 and 250 lb an acre (56, 168, and 280 kg ha-1) superphosphate annually. The effects of increases in the rate of stocking and the amount of superphosphate applied, on wool quality traits and gross margin returns during the entire period and on wool production from 1967 to 1969 are reported. In each year (1967 to 1969) wool production responded to an increase in superphosphate application from 50 to 150 lb but not to an increase from 150 to 250 lb. The response was substantial only in 1968. All wool traits were affected by the level of superphosphate in one or more years. In terms of gross margin returns ($/acre) it was profitable to apply more than 50 lb an acre of superphosphate in 1966 only. In 1969 it was clearly unprofitable to do so, and in 1965, 1967, and 1968 there was no economic advantage to any particular level of superphosphate application within the given cost structure.