The relative productivity and profitability of three grazing systems and two pasture types for a wool production enterprise in the south west of Western Australia were analysed using a bio-economic model. Farmers were interviewed to assess the practicalities of introducing innovative grazing practices and perennial pastures onto grazing properties. The results indicate that pastures based on lucerne were more profitable than pastures based on subterranean clover. In addition, intensive rotational grazing practices such as cell grazing have the potential to substantially increase the profitability of grazing enterprises on both annual and perennial pasture. This research shows that if farmers adopt practices such as cell grazing they may be able to increase the area that they can profitably plant to perennial pastures, thus reducing the potential impact of dryland salinity.

Case Studies

Seven Western Australian farmers were interviewed to investigate the practicalities of applying rotational type grazing practices and introducing perennial pastures onto their farms. The interviews were conducted in 2002 and 2003 and involved an informal discussion followed by some pasture inspections. All of the farmers interviewed practice some form of rotational grazing and consider it an essential component to incorporating perennials into their farming enterprises. Many of the farmers selected (based on their use of rotational type grazing practices and incorporation of perennial pastures) for the case studies have been taught to use, and are using, a grazing planning process which involves planning grazing movements in the rotation on a chart (5). This helps to maintain adequate grazing and recovery periods relative to the pasture growth rate. Some form of planning and budgeting of grazing management is performed by all of the farmers and is considered an important aspect of their success. Perennial pastures are providing, or are seen as having the potential to provide, lower costs, a more even supply of green feed, new opportunities for livestock production and more sustainable farming enterprises.

Bio-economic modelling

This study used a bio-economic modelling approach to compare the profitability of three grazing systems on two pasture types for the south west of WA. The analysis focused on wool production in the North Stirlings Pallinup sub region and data relevant to this area was used to calibrate the model. The stocking rate for each system was maximised using the tool ‘solver’ in Microsoft Excel.

The three grazing systems were: (a) cell grazing, an intensive form of rotational grazing with sixteen paddocks, and based on varying the pasture recovery period according to the growth rate of the plants and grazing each paddock quickly to meet the nutritional needs of the animals; (b) rotational grazing, based on a simple four-paddock rotation using more fixed grazing and recovery periods throughout the year; and (c) continuous grazing, where sheep are set-stocked on a single paddock with no rotation. Each grazing system was evaluated on two pasture types; annual pasture based on subterranean clover (Trifolium subterranean L.) and perennial pasture based on lucerne (Medicago sativa L. ssp. sativa). The pasture types represented in the analysis both had a mixed component of annual species. Also the dominant components of the sward were represented in a generic rather than a specific way.

The alternative grazing systems and pasture types were represented in the model using the animal production functions in ‘Feeding standards for Australian livestock: ruminants’ (6) and the approach developed for the South Coast and Great Southern versions (7) of MIDAS (Model of an Integrated Dryland Agricultural System) (8). As this model represents continuous grazing systems on predominantly annual pastures, additional parameters which relate to alternative grazing practices and pasture types were included in sensitivity analyses. They included the lack of persistence of perennial species under continuous grazing (9), the spatial heterogeneity of grazing (patch grazing) under continuous and simple rotational grazing practices (10-12), the increase in pasture productivity due to an increase in the level of water-soluble carbohydrates under intensive rotational grazing (13-15), and increases in the amount of pasture lost from the system as a result of livestock grazing at low stocking densities under continuous and simple rotational grazing practices (16,17).

Results

Three analyses were undertaken; a baseline analysis, an individual parameter and multiple-parameter sensitivity analysis. Table 1 shows the legend used to identify the grazing systems, pasture types and parameters used in the analyses.

Table 1: Results legend used to identify the grazing systems, pasture types and additional parameters used in the analyses.
N.B. Percentage values for heterogeneity refer to the proportion of time spent grazing in each of four patches within a paddock.


The results of the baseline analysis (Table 2) demonstrated that lucerne-based pasture was more profitable than annual pasture. It shows that at the baseline level the most profitable option is lucerne pasture continuously grazed and at the very least there is only a marginal loss in profitability from adopting the more intensive cell grazing system. However, there are some important considerations which must be included to make this analysis more realistic. These were included in the individual parameter and multiple-parameter sensitivity analyses.

Table 2: Baseline results- gross margin ($/ha) based on low, medium and high wool prices, for a wool enterprise in south west WA when annual (AP) and lucerne-based (LP) pastures were set-stocked (C) and rotationally grazed, simply (R) and intensively (CG).

The results of the individual parameter sensitivity analysis (Table 3) indicate that, when additional parameters are included in the analysis, rotational and cell grazing systems become more profitable. This shows that there is potential for a substantial increase in the profitability of both annual and perennial pastures under cell grazing practices. It should be noted that the decrease in persistence of lucerne under continuous grazing is not likely to adequately represent the ‘rapid stand decline’ documented in the literature (9) for this practice, even at the highest persistence decrease tested in the analyses.

Table 3: Individual parameter sensitivity analysis- gross margin ($/ha) based on medium wool price, for a wool enterprise in south west WA when annual (AP) and lucerne-based (LP) pastures were set-stocked (C) and rotationally grazed, simply (R) and intensively (CG).

The results of the multiple-parameter sensitivity analysis (Table 4) indicate that when combinations of these factors are included in the analysis intensive rotational grazing systems, such as cell grazing, are more profitable and would be of interest to farmers.

Table 4: Multiple-parameter sensitivity analysis - highest gross margin rankings, for a wool enterprise in south west WA when annual (AP) and lucerne-based (LP) pastures were set-stocked (C) and rotationally grazed, simply (R) and intensively (CG).

The results over a wider range of parameter combinations provide confidence that alternative grazing practices such as cell grazing are at least as profitable as traditional practices in the region. Productivity and profitability can be increased when suitable perennial pasture species, such as lucerne, are introduced into the farming system. There is also potential for significant increases in productivity and profitability under cell grazing practices based on both annual and perennial pastures.

Conclusions

In suitable environments in the south west of Western Australia lucerne can increase the profitability of grazing operations. Adopting more intensive rotational grazing practices such as cell grazing could lead to further improvements to the profitability of livestock enterprises grazing perennial-based pastures. This could help farmers to increase the area that they can profitably plant to perennial pastures, such as lucerne, and so potentially help achieve greater control of dryland salinity.

References

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Acknowledgements

The authors would like to acknowledge, the outstanding contribution of Michael O’Connell to this analysis and, the financial assistance and support from the Australian Research Council, the Department of Agriculture Western Australia and the Cooperative Research Centre for Plant-Based Management of Dryland Salinity.

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Citation: Sounness, M., Pannell, D. and Schilizzi, S. (2004) Innovative grazing systems for Western Australia: meeting the perennial challenge, In. "Salinity Solutions". Proceedings of the Salinity Solutions Conference " Working with Science and Society" 2 - 5 August 2004, Bendigo, Victoria.