Reimagining the northern Australian beef industry; review of feedbase opportunities for growth

Introduction

The northern Australian cattle industry is relatively young compared with other pastoral areas of the world, with cattle being introduced by European settlers in the 1800s (Parsonson 1998). The growth of the cattle industry in northern Australia was associated with private initiatives and government schemes to improve cattle genetics, develop the land, control disease and develop infrastructure and new markets, such as the expansion of the live export industry. In particular, replacement of British breeds susceptible to ticks and heat with tropically adapted Bos indicus genotypes in the mid-20th century accelerated the growth of the northern beef industry (Bell et al. 2011). The brigalow (Acacia harpophylla) clearances during the 1960s and 1970s in Queensland, in large measure realised through post-war developments in mechanisation, released approximately 20 million hectares of country, with the majority going into a monoculture of buffel (Cenchrus ciliaris) grass pastures for beef production (Thornton and Elledge 2022). During this time the recognition of the importance of adequate phosphorus nutrition further contributed to improvements in the productivity of the industry (Dixon et al. 2020). The development of ‘the Beef Roads Scheme’ across the north was and continues to be a game changer by improving supply chains and allowing mass movement of cattle during drought or to markets and for the movement of hay and supplements (Beef Roads 2024). Another game changer of the 20th century was the eradication of brucellosis through the Brucellosis and Tuberculosis Eradication Campaign (BTEC; Lehane 1996) More intensive management practices such as the establishment of water and fencing infrastructure were also introduced to the less intensively developed parts of the northern beef industry such as Cape York and the Kimberley, at this time (McKeon et al. 2004).

These transformative developments from past century transformed the northern cattle industry from a ‘frontier’ into a well-connected and sophisticated pastoral industry, in at least the parts of northern Australia better endowed with soils, transport infrastructure and access to markets (McDonald 1981). However, this transition was not universal and today many producers are yet to take full advantage of both historic and ongoing industry developments and innovation.

In 1953, there were approximately 7 million cattle in northern Australia (Kelly and Williams 1953) compared with approximately 14.5 million in 2023 (MLA 2023). Fordyce et al. (2023) suggested national cattle numbers to be considerably higher (33 million) than survey estimates and recent estimates by the Australian Bureau of Statistics, by using new methods and data sources (ABS 2024), suggest that cattle numbers are likely to be about 20% higher than originally reported. Beef cattle numbers in Australia have reached a plateau at between 20 and 27 (26–33 new method) million head over the past 10 years (Fig. 1; MLA 2023) Of these, approximately 60% are to be found in northern Australia (ABS 2024). This plateau in national production contrasts with the global increase in demand for beef and the growth of emerging markets in China and Southeast Asia (Greenwood et al. 2018; Searchinger et al. 2019). Several financial analyses of the northern beef industry suggest that profitability is declining owing to lack of operational scale, poor operational efficiency, declining indexed prices for sales and increased input costs (Holmes 2015; Holmes et al. 2017; Bowen and Chudleigh 2018; McLean et al. 2018; Bowen et al. 2019). McLean et al. (2023) reported that approximately half of northern businesses carry <800 adult equivalents (AE) and, on average, are unprofitable. Holmes (2015) also concluded that 80% of northern businesses are not economically sustainable long term. However, it should also be noted that high beef prices in 2022 dramatically improved the profitability of the whole beef industry (McLean et al. 2023). As a result of these financial realities, total factor productivity of the industry has declined since the late 1990s (ABARES 2023). There is also some evidence that land condition and carrying capacity are in decline across northern Australia (KA Shaw, JW Rolfe, T Beutel, BH English, ND Gobius, DE Jones, unpubl. data).

Fig. 1.

Beef cattle numbers in Australia (ABS 2024). The blue bars represent data using the former methods of ABS (Source: Australian Bureau of Statistics, Agricultural Commodities, Australia 2021–22 financial year, MLA (2023), the orange bars represent the data using the new ABS methods (ABS 2024).

To reverse these trends the industry needs new game changers to build on those of the mid-20th century. This review considers options aimed at capitalising on existing natural resources of the north and their potential use in the beef industry. The feedbase is the primary driver for both animal growth and reproductive efficiency. Limitations in availability and quality of the feedbase both within and across seasons restricts the ability of northern cattle to reach their genetic potential for reproduction and growth.

To achieve economy of scale, viability at the property level has often been sought through adoption of tried and tested methods and acquisition of more land to keep pace with increasing costs and lower returns. Adoption of improved animal genetics, pasture improvement, precision grazing management and information technology (IT) contribute to incremental change. Although the importance of continual improvement of existing systems is acknowledged, this review focusses on blue sky thinking around shifting the paradigm through the lens of alternative or novel cattle feed resources. Harnessing the unlimited solar radiation and a fickle water supply are key to exploiting areas that can withstand intensification. Many permutations exist. For instance, intensification of land use where practicable also realises the opportunity of selective de-intensification. Overall, changes in how beef production is distributed from within the property to across regional scales can also benefit environmental and biodiversity outcomes. At the property scale, stocking rates can be reduced on marginal or degraded land, and carrying capacity can be increased on better soils, with overall stock numbers remaining the same. At a regional scale, high-input beef production can complement more extensive pastoral beef production to increase overall regional returns.

The objective of this review is to explore an alternative model, whereby increased productivity and economic viability are achieved through a mosaic of intensified land uses interspersed within a sustainable pastoral landscape. Consequently, there may arise opportunity to reduce and better manage grazing pressure on vulnerable land, thus potentially benefiting the environment while simultaneously improving whole-of-property herd productivity.

Constraints and future impacts to the northern beef industry

The northern Australia beef situation analysis (Chilcott et al. 2020) provided an in-depth review of the current ‘state of play’ of the northern beef industry and identified constraints to address that lift productivity and profitability. These constraints, including feedbase, the animal and herd structure, climate, geography, and human capital, are intrinsically linked to the dominant production systems utilising low-input–low-output pastoral methods (Table 1).

Any future scoping must be cognisant of future mega-shocks that could affect the industry (Hajkowicz and Eady 2015). For the northern beef sector, climate change and variability, societal concerns around the environment and animal welfare, and land tenure rank as three potential disruptors of the production options proposed here (Table 1). For example, increased temperatures could negatively influence the growth pattern and quality of forages (Henry et al. 2012). Public perceptions regarding the production and consumption of beef continue to influence consumer sentiment and the regulatory environment affecting markets and freedom to operate (Chilcott et al. 2020). Such issues could have negative impacts on the current scale of the industry and future opportunities for a reimagined beef sector. In future, a more robust and integrated feedbase for the industry is likely to have both positive and negative impacts on consumer sentiment (Moran-Ordonez et al. 2017). For example, reducing grazing pressure on sensitive environments will improve ecosystem integrity (Kemp and Michalk 2007; Neilly et al. 2018; Runting et al. 2024); however, in other areas, diverse grasslands on fertile soils will be replaced by rotational monocultures of crops or forages. Optimising the balance between these two opposing impacts is key to sustained development of the northern beef industry. Irrigation will reduce reliance on uncertain rainfall patterns (Watson et al. 2023). Advances in information technology (IT) will have a transformative effect increasing labour efficiency and allowing for custom management options within the herd (Aquilani et al. 2022). Similarly, artificial intelligence (AI) technology has potential for enhancing production efficiency and product quality (Wang and Li 2024).

Nutritional options to re-imagine the northern beef industry

Beef production is a multi-faceted endeavour involving the integration of a range of disciplines. Underpinning beef production is the conversion of energy, protein and micronutrients harvested from the environment into a valuable product for human consumption, namely beef. This review investigates the biological potential of novel nutritional pathways for beef production in the north. The underpinning hypothesis is that a multiplicity of approaches can be used to sustainably and more effectively harvest biomass for beef production than the current system that relies predominantly on extensive grazing of native or modified grasslands with supplementation to meet obvious deficiencies. The potential benefit for the industry and the environment is the opportunity to intensify production where resources allow, while reducing grazing pressure in areas better suited to beef production, in combination with environmental, cultural, or other revenue streams.

The primary metric for evaluation in this paper is biological feasibility using known technologies. Although such technologies exist for all the examples provided in this paper, their economic viability in northern Australian rangelands is, at best, questionable under current conditions. However, in the future, current economic constraints may become less important, as global challenges change (Hajkowicz and Eady 2015). For many of the options considered, the economic feasibility is highly dependent on future economic conditions such as capital investments, input costs, beef prices, etc. Robust economic analyses for several similar or related scenarios have been published (e.g. Bowen and Chudleigh 2018, 2019; Bowen et al. 2018, 2019). However, the current economic feasibility of options, although a useful metric in the near-term, should not rule out potential future options that could operate under different financial realities.

Five production options were identified, three of which are already well characterised but under-adopted (pasture legumes, silage, mosaic irrigation), and two of which are novel to northern beef production (cropping co-products, lignocellulosic biomass; Table 2). Two of the five options are cross-cutting technologies (irrigation and lignocellulosic biomass) that provide benefits when matched with existing and novel production systems. Although each of these opportunities alone offers potential, it is the creative application of combinations of opportunities into a paradigm shift that could bring the greatest reward for the northern beef industry. For the purposes of this review, northern Australia is defined as all of Queensland and the Northern Territory, plus the Kimberley and Pilbara regions of Western Australia, an area of approximately 4 million km² recognised by the Northern Australia Beef Research Council (NABRC) as geographically and commercially relevant to the northern beef industry. The geographic areas likely to be suited to the application of these technologies are given in Figs 2 and 3. Northern Australia is diverse, with rainfall influencing the productive capacity of the landbase. Generally, rainfall declines from east to west and the stocking rates decline accordingly. In high-rainfall areas, stocking rates can be 0.3–0.5 adult equivalents (AE; 1 AE is equivalent to a 450 kg steer)/km², but these decline to as little as 0–10 AE/km² in the rainfall zones below 400 mm (Fig. 2). Commensurate with the decline in stocking rates, the property size increases from approximately 650 km² to almost 1400 km² (MLA 2014). Generally, soils are of low fertility and rainfall is highly seasonal, with the majority of rain fall in the monsoonal wet season from approximately December to April. Consequently, pasture quality is variable, being low in nutritive value in the dry season and higher in the wet season. Dry-matter (DM) digestibility of the diet can vary between 40% and 65% and crude protein between 4% and 12% DM (Charmley et al. 2023b).

Fig. 2.

(a) Rainfall map of northern Australia, (b) rural properties, also showing the major catchments of northern Australia, (c) cattle density map of northern Australia, and (d) current production areas of cane, cotton and bananas and potential areas for irrigation that could support various crops and forages for beef production in selected catchments; Mitchell (A), Gilbert (B), Flinders (C), southern gulf (Gregory and Leichardt; D), Roper (E), Darwin area (F), Victoria (G), and Fitzroy (H).

Fig. 3.

(a) Areas for potential silage and (b) legume production in northern Australia: Desmanthus, (c) Stylosanthes, and (d) Leucaena. For all maps, the area is defined by rainfall plus land type and is restricted to pastoral lands with less than 2% slope. Silage production from forages without irrigation is restricted to >700 mm rainfall and clay to loam soils. Irrigation extends the area to include rainfall between the 400 and 700 mm isohyets. Desmanthus is restricted to >400 mm rainfall and vertosols plus sodosols. Stylos are restricted to >500 mm rainfall on lighter soils, apart from S. seabrana, which also tolerates vertosols and sodosols. Leucaena is restricted to >650 mm rainfall on heavier soils such as vertosols and sodosols.

Under-adoption of proven technologies and production systems remains a perennial problem in northern Australia and has been attributed to a lack of business skills and financial literacy (Holmes 2015) and the need to manage risk and uncertainty (Webb et al. (2013). The problem is well known and understood but solutions remain elusive. Marshall et al. (2014) surveyed 240 northern cattle producers and found that over 80% of respondents were averse to change. They held strong association with the land and their lifestyle and had low adaptive capacity for change. For these individuals the simple economic imperative was insufficient motivation to enact a change. The annual and decadal cycles in climate and productivity have been managed and mitigated by a cautious approach both to change and to novel ideas, prioritising stability and resilience ahead of innovation. Relying on past experiences has a major influence on future planning. Northern producers have relied on State departments and organisations such as Meat and Livestock Australia (MLA) to provide development and extension services, with a wide range of programs and demonstration sites. Yet, despite clear evidence that new approaches, such as introduction of pasture legumes, for example, are economically viable, a reluctance to change remains for many producers. The use and availability of networks in northern Australia is limited and strong diverse networks increase trust in and access to information (Marshall et al. 2014). In marked contrast to southern Australia, the use of agricultural consultants is not widespread. The expansive industry and the tyranny of distance makes in-depth, whole-of-enterprise, face-to face consulting difficult and expensive. The agricultural supply industry is also different in the north. In intensive systems sales representatives for feed, seed, chemicals, fertiliser, herbicides and pesticides are in continuous contact with producers providing advice and ideas to embolden producers to make changes. Moreover, such producers are continually observing the ongoing successes and failures of dozens of neighbouring farms as they trial new technologies and enterprise structures. Under more extensive production systems, this network of advice and influence, although still present, is much less pervasive. Without sound holistic advice, the northern producer is left with a myriad of decisions to make regarding adoption and ill-conceived decisions can have a major impact on enterprise viability. In the absence of a de-risked pathway, the safest option is to stick with what one knows.

Marshall et al (2014) concluded that producers were unlikely to respond to traditional sources of information and methods of extension. Yet, these are the producers most likely to benefit. A subsequent survey of northern producers (Jakku et al. 2022) highlighted more pragmatic drivers, including assessment of costs and benefits of adoption, increasing efficiency and ease with which a change fitted into the existing operation. Taken together, it is clear that producers rely on a myriad of often conflicting factors in decision making and this complexity often favours remaining with the status quo. Is it simply that the pain of change is greater than the reward, when business as usual is safe and viable? Future mega-shocks, such as climate variability, may change this paradigm. In the past mega-shocks could be positive and included massive government intervention in roads and animal health, for example. These investments led to wholescale adoption of the benefits. In the future, it is most likely that these positive mega-shocks will come from private investment in the sector, rather than government, leading to increased corporatisation and vertical integration. Whether or not these potential changes will be perceived as positive remains to be seen. Notwithstanding these issues, the purpose of this paper is to highlight possibilities available when the feedbase resources of the north are viewed purely from the perspective of what is biologically possible. In future, these options may become both significantly cheaper and substantially derisked as markets change, regional infrastructure and technical support improves, and significant corporate or government investment is mobilised.

Legumes to improve nutritive value of pastures

The northern rangelands are dominated by C4 grasses noted for their poor nutritive value and decline in quality with advancing maturity (Minson 1981). The introduction of tropically-adapted legumes into these grazed environments simultaneously addresses the problem of low nitrogen (N) status of soils and low dietary protein intake by grazing ruminants (Coates et al. 1990; Shelton et al. 2005; Ash et al. 2015; Peck et al. 2022) and has been widely recognised. For example, Peck et al. (2017) estimated that establishing legumes in central Queensland was the most cost-effective option to offset productivity decline in the Brigalow belt, a bioregion west of the Dividing Range and extending from approximately Townsville in the north to northern New South Wales in the south and Charleville in the west. However, their widespread adoption has been less than hoped for and limited by the availability of adapted species (Schultze-Kraft et al. 2018), establishment failure and costs, and a lack of agronomic understanding by graziers. A range of legumes are adapted to northern Australia varying in growth habit from herbs to trees (Castro-Montoya and Dickhoefer 2020). Australia has a rich diversity of native legumes (Lewis et al. 2005) of which only some are described as productive and palatable for livestock, whereas others are of limited significance for grazing because of toxicity limitations (Hacker 1990). Leslie et al. (1987) suggested that many of our productive, palatable species declined in abundance after the introduction of domestic livestock into Australia. Little emphasis has been placed on research of our native legumes for grazing and MLA (2011) stated that information on the productivity and quality of native legumes is scant. Hacker (1990) nominated several genera of relevance to northern Australia that warrant further research effort with regard to potential livestock production benefits, including, among others, Alysicarpus, Desmodium, Glycine, Rhynchosia, and Vigna. With a changing climate and biosecurity issues around introduced legumes, some of these native species could well be a part of re-imagining the northern feedbase in the future (Whattam et al. 2024).

Historically, far greater emphasis has been placed on the introduction, evaluation, and commercialisation of exotic herbaceous legumes for northern Australia, rather than the native species. The majority of exotic species originate from Central and South America. Tropical herbaceous legumes that have been successfully introduced and adopted commercially, depending on region/environment, include the Arachis, Aeschynomene, Centrosema, Chamaecrista, Clitoria, Desmanthus, Desmodium, Dolichos, Leucaena, Macroptilium, Neonotonia, Stylosanthes and Vigna genera. Among these, many species and varieties have been released (Cook et al. 2020), including most notably several Desmanthus (JCU 1–9; Gardiner 2016) and Stylosanthes species (Cook et al. 2020; Peck et al. 2022). The Australian Pasture Gene (APG) Bank holds some 70,000 accessions of tropical and temperate forage accessions. Many are untested and may hold genetic potential for traits such as drought resilience, antimethanogenic activity, anthelmintic properties and other ecosystem benefits as yet undefined (Durmic et al. 2017; Tunkala et al. 2023).

Plant breeding of pasture legumes with adaptations to northern rangelands is quite limited but offers potential for new and novel crosses including intraspecific, interspecific and even intergeneric crosses, some of which are described by Sturat and Kempe (2017). In addition, Gardiner (2016), Gardiner et al. (2017) and Peck et al. (2022) have revisited old legume trial sites and selected survivors, resulting in the development of new cultivars of Desmanthus and Stylosanthes.

Many native browse species are under-exploited and may be considered multipurpose species providing shade, shelter, fodder, N fixation, carbon sequestration, and ecosystem services (Gutteridge and Shelton 1994; Gardiner et al. 2025). In times of drought, ‘topfeed’ or browse species assume the greatest importance (Chippendale and Jephcott 1963; Everist 1985). Among native browse species, mulga (Acacia aneura) is the most important fodder tree in Australia, although it is not widespread in the north (Everist 1985).

The following three species relevant to the grazing lands in parts of northern Australia are discussed in greater detail here: Stylosanthes, Desmanthus, and Leucaena. Of these, the stylos are most widely utilised and distributed, and demonstrate the potential of tropical legumes (Fig. 3). It can be argued that the introduction of legumes from the Stylosanthes genus has already revolutionised sown pasture development in northern Australia (Bishop and Hilder 2005). However, for the purposes of this review, we consider that the potential for legumes in northern Australia is yet to be fully realised and is therefore worthy of inclusion as one aspect of the feedbase for consideration. If the current estimated areas of established stylos, Desmanthus and Leucaena, are combined with approximate stocking rates, then it is estimated that only approximately 300,000–350,000 of the 14.5–16 million beef cattle in northern Australia are grazing pastures with substantial legume biomass (Table 3). The genus Stylosanthes includes a number of species that are widely adapted to northern Australia, including S. scabra (e.g. cv. Seca), S. hamata (e.g. cv. Verano), and S. seabrana (e.g. cv. Unica). They are adapted to sandy loam soils (with the exception of S. seabrana, which prefers clay soils) and the higher-rainfall (>600 mm) areas of northern Queensland (Walker et al. 2022) and sporadically in the Northern Territory and the Kimberley region of Western Australia (Fig. 3). It has been reported that, in 2000, there were approximately 1 million hectares of pastures in northern Australia where stylos have been introduced (Noble et al. 2000). Since then, the area has increased, and stylos represent the most common of tropical legumes in northern Australia, found across approximately 1.5 million hectares, approximately 0.4% of the north as defined in this review (Table 3).

Desmanthus is one of the few legume genera adapted to clay (vertosols) soils prevalent in western Queensland (Gardiner et al. 2013; Gardiner et al. 2017), but is also found across the Northern Territory and in Western Australia (Fig. 3). Uptake by the industry is relatively recent, and it is estimated that in 2023 Desmanthus had been introduced to more than 100,000 ha of pastures. However, there is potential for more widespread establishment across 35 million hectares of suitable edaphic and climatic zones (Fig. 3).

Leucaena was first bred for northern Australia in the 1960s and 1970s, but uptake by the industry has been less than expected. It offers potential in the frost-free higher-rainfall (>650 mm) coastal zone or under irrigation on well drained, neutral to alkaline deep soils (Shelton and Dalzell 2007). Recent estimates of planted Leucaena range from 123,500 ha in Queensland (Beutel et al. 2018) to 130,000 ha across all of northern Australia (Buck et al. 2019). However, Shelton and Dalzell (2007) considered that there was potential for 13 million hectares (Fig. 3, Table 3). Poor adoption is possibly related to the challenges and expense of establishing a row crop in pastoral landscapes because of a lack of farm infrastructure and expertise and regional support services, or can be simply due to a lack of seed for new cultivars. The interspecific breeding of Leucaena has recently developed the psyllid tolerant cultivar Redlands and it is expected that this will see the expansion of Leucaena into coastal areas (Dalzell 2019; Shelton et al. 2020), with an additional 1.2 million hectares of suitable land (Shelton and Dalzell 2007). Leucaena has weedy traits, including the abundant production of hard seeds, which has led to it being a declared weed in some regions (QDAF 2024). In Western Australia, Leucaena is classified as a high or very high weed risk assessment (Department of Primary Industries and Regional Development, Western Australia 2022) and its cultivation is highly restricted. The production of sterile (seedless) Leucaena has the potential to alleviate the weediness issue (McMillan et al. 2019; Real et al. 2023), although the requirement for vegetative propagation may slow adoption. Leucaena also contains mimosine, which together with its breakdown products are toxic to ruminants (Dalzell et al. 2012). Toxicity can be avoided by inoculation either through dosing or passive inoculation from the environment with Synergistes jonesii, a bacterium capable of degrading the toxic compounds (Halliday et al. 2014).

Silage

Ensiling offers the possibility of conserving tropical forages at optimum nutritive value for livestock production. Nutritive value can be optimised by selecting the desired growth stage for a particular class of livestock or ration formulation. Silage fermentation can be controlled by the use of inoculants and wilting and feed-out losses can be controlled by good silo management and an appropriate inoculant. Silage making is a high-input technology requiring significant capital investment and labour and should be considered as a component of an intensive beef production system. However, bale silage offers a lower cost alternative that can have application for small-scale production.

Ensiling is an ancient conservation method for lower-DM vegetation relying on the production of acids by anaerobic microflora to conserve the nutrients in the biomass. Various techniques have been developed suited to all scales of production, but all rely on the exclusion of air (oxygen) from the ensiled mass (McDonald et al. 1991; Wilkinson et al. 2003). In northern Australia, the seasonal pattern of summer rainfall followed by an extended dry season produces a short but intense growing season for forages, and silage is ideally suited for such seasonal growth patterns. Ensiling is practised only to a limited degree in northern Australia and is primarily associated with large-scale backgrounding and finishing operations using ensiled maize or sorghum stored in bunker or pit silos. Ensiling tropical forages is more common in Brazil where grasses such as Megathyrsus maximus, Urochloa decumbens, Urochloa brizantha, and Cenchrus clandestinus are used (Da Silva et al. 2019). In northern Australia, there is potential for ensiling a range of crops as well as ensiling of co-products from the cane, citrus and horticultural industries. However, scale and consistency of supply currently limit these options. The preferred method of ensiling is precision-chop harvesting of material wilted to between 35% and 45% DM, depending on the crop and storage method. To control feed-out losses, storage in bunker or pit silos is preferred, with the face designed to ensure the exposure of the silage surface is limited to 2–3 days. Bale silage (square or round) is an option for small-scale opportunistic forage conservation (Piltz et al. 2022).

Ensiling offers a method whereby forages can be harvested at optimum yield and quality and stored for use either during feed gaps or fed out to specific high-producing livestock within the herd. Compared with grazing, ensiling allows for timed harvests to optimise yield with quality, and benefits the physiology of the grass through appropriate regrowth periods (Da Silva et al. 2015). In practice, harvesting at optimum periods may not be possible because of weather events and growth patterns of grasses and may be interrupted by lack of rainfall. Nevertheless, the role for an intensive silage system using adapted perennial tropical grasses under irrigation could provide a reliable source of high-quality feed for beef operations. Although the nutritive value of silages is closely related to that of the original forage, it is typically somewhat reduced following fermentation (McDonald et al. 1991).

Unlike hay, silage is difficult and costly to transport. Silage lends itself to production at or close to the feeding site. It therefore necessitates the cost and capability to establish infrastructure and equipment on the farm. Whereas the use of dedicated contractors can defray the operational costs, availability of contractors in the north remains a constraint. Nevertheless, systems exist for all scales of operation and offer an option for high-quality, on-farm fodder production.

Estimating the current and potential quantity of silage production in northern Australia is difficult. According to ABS (2024) there were 459,000 ha of sorghum and 22,000 ha of maize grown in Queensland in 2021/22. Assuming a yield of 10 Mg DM/ha and 5% of the area being devoted to silage, the total quantity of annual crop silage would be about 225,000 Mg of DM. Hay and silage production from pastureland in northern Australia accounts for approximately 600,000 Mg/annum (ABS 2024). A conservative estimate would suggest that the north currently produces only about 0.75 million megagrams (annual and perennial crops combined) of hay/silage annually (DM basis). The challenge in a future scenario would be to increase the production of high-quality silage from annuals such as maize and sorghum and also encourage the use of perennial crops for silage, possibly with the increased use of irrigation (see section on irrigation). The area used for hay/silage production in northern Australia is relatively small. ABS statistics for Queensland and the Northern Territory estimate an area of only 74,266 ha. Yet modelling based on rainfall and soil type suggests that large areas are theoretically suitable (Fig. 3) either as rainfed or irrigated production. A 10-fold increase in the area devoted to silage production could readily be accomplished and yet still only account for less than a million hectares of just under 400 million hectares in the area covered in this review.

Tropical perennial grasses

Biomass accumulation rates of tropical grasses are very high following the break of season and grasses exhibit a sigmoidal growth pattern (Brougham 1955). Tropical grasses produce a higher proportion of stem during the vegetative stage of growth than do temperate forages (Da Silva et al. 2015), which results in a more rapid decline in digestibility and CP than with temperate grasses. Nevertheless, an optimum yield of digestible nutrients can be achieved by harvesting during the linear increase in biomass after 3–4 weeks regrowth at 95% light interception (Da Silva et al. 2019). Research with Megathyrsus maximus has demonstrated biomass yield of approximately 5 Mg/ha from a single harvest, with in vitro organic matter digestibility of 58%, and CP of 11% (Da Silva et al. 2019). Under optimum conditions of soil fertility and irrigation in the tropics, multiple harvests per year can be expected. Fig. 4 shows a stylised pattern of crop growth and nutritive value for intensive silage production with perennial grasses. Harvesting before the yield asymptote will increase individual animal performance at the expense of performance per hectare. Harvesting after the point of maximum digestible yield will reduce both individual animal performance and performance per hectare. Harvesting at the point of maximum digestible yield optimises both gain per head and per hectare.

Fig. 4.

Generalised relationship between quality (digestibility) and quantity (yield) of a tropical grass, showing the optimum harvest date for yield of digestible nutrients.

Tropical grasses are generally considered more difficult to ensile than are temperate grasses (Parvin et al. 2010; Bernardes et al. 2018), being lower in water-soluble carbohydrate (WSC), the substrate for microbial growth during ensiling (Bernardes et al. 2018; Piltz et al. 2022). Furthermore, higher ambient temperatures at ensiling favour the less effective heterolactic over homolactic fermentations (Bernardes et al. 2018). Piltz et al. (2022) showed that increasing WSC concentration by wilting to increase DM content improved silage fermentation by favouring homolactic bacteria over spoilage organisms such as Clostridia, and heterolactic bacteria. The results also showed the importance of a silage inoculant on the extent and quality of fermentation (Table 5).

Typically, heterolactic fermentations contain less lactic acid and increased concentrations of acetic and other volatile fatty acids and are generally considered to be of lower nutritive value for livestock because of reduced feed intake (McDonald et al. 1991). However, higher concentrations of acetic and butyric acids can impart greater aerobic stability during feeding of silage (Arriola et al. 2021). This is particularly beneficial under the higher ambient temperatures experienced in northern Australia (Piltz et al. 2022). Under tropical conditions use of a microbial inoculant is recommended to improve fermentation and aerobic stability (Parvin et al. 2010; Arriola et al. 2021; Piltz et al. 2022). Recently, the silage inoculant containing Lactobacillus buchneri has shown promise in improving aerobic stability of silages. L. buchneri converts lactate to acetate and 1,2 propanediol, two compounds that inhibit aerobic deterioration of silages by yeasts and moulds (Arriola et al. 2021).

Mosaic irrigation for livestock feed

Northern Australia receives between 8 and 10 sunshine hours per day for plant photosynthesis (Bureau of Meteorology 2023). However, water is often lacking, with much of the grazing areas receiving less than 600 mm rainfall per year, with most of this occurring in the wet season between approximately December and April (Bureau of Meteorology 2023). This constrains the production potential of the landbase and particularly the better-quality soils.

Growing crops on-property for forage, hay or silage in the extensive grazing areas of northern Australia (particularly north of the Tropic of Capricorn) is a concept that has strong support in principle but is rarely practised (Grice et al. 2013; MacLeod et al. 2018; Moore et al. 2021). The high capital costs of irrigation schemes at all scales have generally ruled out the production of forages for beef production in favour of higher-value crops such as vegetables, cotton and pulse crops (Ambiel et al. 2019). We acknowledge that despite the biophysical possibilities for mosaic agriculture, there are a large number of constraints including economic, regulatory, socio-political and cultural, which have so far precluded mosaic agriculture on most cattle enterprises in the extensive cattle-producing (predominantly Crown leasehold) areas of northern Australia.

Theoretically, the use of on-farm irrigated crops for forage or silage production would allow producers greater options for marketing cattle, such as meeting market LW specifications for cattle at a younger age, meeting the specifications required for markets different from those typically targeted by cattle enterprises in the region, providing cattle that meet market specification at a different time of the year, and for supplementary feeding during drought. Forages or silage may also allow graziers to implement management strategies, such as early weaning, weaner feeding or drought feeding, which should lead to flow-on benefits throughout the herd, including increased reproductive rates. Some of these management strategies are already being practised within the extensive cattle growing areas of northern Australia but are reliant on hay or other supplements purchased on the open market. By growing crops on-property, the scale of these management interventions might be increased, at reduced net cost. Furthermore, the addition of irrigated crops may also allow graziers to increase the total number of cattle that can be sustainably carried on the property, while maintaining the same (or lower) utilisation rates of native pasture.

Earlier turn-off of cattle with mosaic agriculture

Despite its inherent attractiveness, there is little mosaic agriculture practised on cattle properties in the more extensive parts of northern Australia and very little commercial-scale data are available where it has been tried. However, insights on the impact on cattle turn-off through feeding forages or hay can be gained through bio-economic modelling.

In the following example, the bioeconomic model CLEM (Crop Livestock Enterprise Model) was used to represent a beef cattle enterprise in the Victoria River catchment of the Northern Territory (Webster et al. 2024) and has been adapted here to suit the purposes of this review. The Victoria catchment is approximately 8.2 million ha, of which about 62% is used for extensive cattle production. There is virtually no irrigation in the catchment and live cattle export is the primary market.

In the model, irrigation was used to grow forage sorghum, lablab or Rhodes grass. Lablab was grazed while forage sorghum and Rhodes grass were conserved as hay. A baseline enterprise was included in the model. Cattle were mustered twice per year in May or September. All weaned males, below the age of 24 months were put onto irrigated forage or fed hay between June and September (for the shorter growing-season lablab) or October (forage sorghum and Rhodes grass). Cattle given hay also had access to native pasture. Steers were sold at a minimum sale weight of 280 kg in May, September (baseline or lablab) or October (forage sorghum or Rhodes grass) (Table 6).

Table 6.Fermentation characteristics of tropical silages adapted from Piltz et al. (2022).

Item	Moderate wilt		High wilt
	Control	Inoculant	Control	Inoculant
Dry matter (%)	31.7	34.0	45.0	42.2
CP (% DM)	14.5	14.1	13.6	13.3
pH	5.40	4.35	5.90	4.30
NH3-N (g/kg DM)	8.30	4.65	5.00	4.00
Fermentation acids (g/kg DM)
Lactic	17.5	52.0	5.10	47.5
Acetic	6.10	8.55	1.30	4.35
Iso-butyric	0.016	0.006	0.008	0.004
Total	6.30	9.05	1.40	4.15
Lactic/acetic	2.87	6.28	3.92	12.3

The most obvious biophysical impact of the various feeding strategies was the increase in LW, compared with the base-enterprise (Fig. 5). This allowed a greater proportion of the castrated males to be sold earlier, at the minimum sale weight of 280 kg. For example, for the two hay options, nearly 79% of the cohort was sold as ‘1-year old’ cattle (i.e. 8–12 months old) in October, whereas no animals under the base-enterprise option met the minimum weight at that time (Table 7). For the baseline cohort, no cattle were sold as ‘1-year olds’ in their first September and 100% were carried over the following wet season, 78% then being sold at the May sale as ‘1.5-year olds’ (i.e. 15–19 months old). The remainder of the baseline cohort were sold the following September (9%) or held over the next wet season and sold in the following May sale (13%). By contrast, for the two hay options, 99% were sold as ‘1.5-year olds’ or younger. On average, cattle fed irrigated forages or hay were sold earlier, at younger ages, than were cattle on the baseline scenario. Irrigation offers management options such as lowering grazing pressure on native pastures, running higher livestock numbers, or retaining cattle on feed to slaughter weights, depending on market opportunities.

Fig. 5.

Monthly mean liveweights for each scenario for male animals born at the end of November. For the purposes of this graph, all sales were switched off in the model, so as to show growth rates over the full period of feeding, without the removal of sale animals having an impact on the mean weights of the remainder of the cohort.

Table 7.Influence of different irrigated forage and beef production scenarios on percentage of cattle sold by age on reaching 280 kg liveweight for a modelled property in the Victoria River catchment (NT).

Item	Base-enterprise	Grazed lablab	Sorghum hay	Rhodes grass hay
‘1-year-olds’ sold September or October	0	63	79	79
‘1.5-year olds’ sold May	78	27	20	20
‘2-year olds’ sold September or October	9	10	1	1
‘2.5-year olds’ sold May	13	0	0	0

Adapted from Webster et al. (2024). The second sale of each year was either September (baseline or lablab) or October (sorghum hay and Rhodes grass hay).

Co-products from other production sectors

Irrigation and rainfed agriculture along the eastern coastal areas of the subtropical and tropical north is focussed on sugarcane, bananas and a range of horticulture crops. All of these produce co-products that potentially have value as feedstock for cattle, particularly for feedlot backgrounding and finishing. In Australia, the adoption of co-products for ruminant feeds has been limited for a variety of reasons listed below:

However, with the increasing costs of feed ingredients, improved infrastructure in northern Australia and cattle processing capacity in the region, the potential to increase use of co-products in beef diets could be realised.

Improving nutritive value of low-quality biomass

In northern Australia, there are ample resources of lignocellulosic materials that with remediation could be a major source of digestible energy for ruminants. Techniques to break down the lignocellulosic bonds in fibrous biomass continue to be developed in both efficiency and sophistication. Two opportunities will be discussed below.

Opportunities in perspective

The options to source alternative feeds for the northern cattle industry each carry pros and cons regarding their potential use. Fig. 6 classifies these options according to their technical challenge and likelihood, and opportunity. Legumes and silage are both shown to be technically feasible and the opportunity for increased adoption is large because there is ample suitable land base for expansion. A seven-fold increase in the proportion of pastures with legumes would be needed to fully utilise the suitable landbase and a 10-fold increase in silage production is technically realistic (Fig. 3). Although these adoption rates are unlikely to be ever achieved, they highlight the unfulfilled potential. Silage conservation is a proven method and offers real opportunity to produce quality livestock feed from annual and perennial forages and vegetable waste. Yet, adoption remains very low, particularly when compared with other countries including Brazil (Bernardes and Do Rêgo 2014) and the United States (Bernardes et al. 2018). Currently, irrigation is used primarily for the production of high-value horticultural and related crops. However, smaller-scale irrigation projects that are integrated closely with beef enterprises would facilitate silage production. Globally, there is increased interest in up-cycling, i.e. diverting waste co-product form agricultural enterprises into valuable commodities. Northern Australia produces crop and vegetable waste at scale in close proximity to a large and expanding beef industry. Novel processes can increase digestibility and nutritive value of co-products at scale to produce energy feedstock for lot-feeding. Expansion of the cotton industry in the north could produce over 300,000 Mg/year cottonseed plus protein break crops (e.g. mung beans), both being quality protein sources to complement high-energy silage, thermally treated bagasse and vegetable waste (ABARES 2024).

Fig. 6.

Schematic showing the opportunity relative to the technical challenge of the five technologies. The size of the coloured ovals represent the potential impact for the industry, and the open ovals demonstrate potential synergies among technologies.

All the above options are technically feasible. Taken individually, each technology offers improvements in animal productivity through the provision of feeds of higher nutritive value. This could be achieved by improving production on farm, for example, by growing crops for silage, or by accessing feed resources such as vegetable co-product off farm. However, the combination of complementary technologies can lead to synergies that amount to more than a simple additive effect. Simple combinations such as irrigation with silage result in less variability in production and the potential for seasonal or year-round feeding of a high-quality forage. Nutritional enhancement of co-products such as bagasse or vegetable waste increases the nutritive value of two underutilised, widespread feed resources in the north. However, the major benefits of these alternative feed sources become more apparent when they are woven into integrated regional production systems. For example, introducing a suitably adapted legume into native pasture could increase carrying capacity by up to 20%. The producer is then faced with options such as increasing the herd size, developing irrigation-fed forage production for an on-farm feedlot or releasing land for environmental co-benefits. Alternatively, integrating feedlot enterprises within a cane-growing region or irrigation schemes could generate income from co-products and break crops while reducing feed costs for the feedlot. In a truly circular economy, manure would then be returned to the intensive cropping enterprise.

In reality there will always be barriers that limit opportunities. Although financial barriers are paramount, even if these are set aside, challenges remain. These include the following:

However, there are opportunities too. Through optimisation of the potential feed resources available, the northern beef industry could expand in a sustainable manner, always under the assumption that systems are economically viable. Under the current economic and financial conditions, most of the discussed technologies are not viable. However, the purpose of this paper is to highlight what could be achieved either through external investment in creation of novel industries, or increased demand and value of beef, or through a combination of both. Today’s beef industry would not be what it is without past investment and entrepreneurship in developing the north. The future industry will depend on creative means of better utilising the north’s resources while maintaining its natural assets. We also recognise that the future of the northern cattle industry will remain contested with the ongoing need to balance environmental outcomes with agricultural production as well as acknowledging the multiple perspectives on how this might be achieved (e.g. Morán-Ordóñez et al. 2017; Runting et al. 2024).

Although all five production options are technically possible, current economic realities of the northern beef industry preclude their wider adoption. However, in other parts of the world, practices such as irrigation, and use of alternative feedstocks in beef production are more prevalent. A key difference between domestic and overseas beef production is the greater intensification of the beef sector in other developed countries, often supported by subsidies. Intensification is associated with higher animal performance and a greater reliance on formulated rations. Such a shift in intensification is occurring in Australia, but at a slower pace. Australian feedlot capacity continues to increase and in 2024 was 1.65 million head (https://www.mla.com.au/news-and-events/industry-news/data-shows-australian-grain-fed-beef-sector-continues-to-grow/). In many overseas countries there is segmentation of breeder and finishing operations, with breeder operations being small, part-time and typically only accounting for a small proportion of the family income. In the USA, for example, average cow--calf herd size is 47 head (USDA 2025), whereas in Canada it is 63 head (Canada Beef 2025). In Australia, breeder operations are commercially more viable, large scale with the herd size in northern Australia ranging from 220 to 44,000 head (MLA 2014). Such pasture-based breeder operations could remain viable in co-existence with an intensive beef finishing sector.

This review has highlighted some alternative feeding practices for the northern beef industry. The intent is not to question the status quo but to demonstrate that there are alternatives that in the future may or may not become economically viable.