How Biodiversity-Friendly Is Regenerative Grazing?

Regenerative grazing management (ReGM) seeks to mimic natural grazing dynamics to restore degraded soils and the ecological processes underpinning sustainable livestock production while enhancing biodiversity. Regenerative grazing, including holistic planned grazing and related methods, is an adaptive, rotational stocking approach in which dense livestock herds are rotated rapidly through multiple paddocks in short bouts of grazing to defoliate plants evenly and infrequently, interspersed with long recovery periods to boost regrowth. The concentrated “hoof action” of herds in ReGM is regarded vital for regenerating soils and ecosystem services. Evidence (from 58 studies) that ReGM benefits biodiversity is reviewed. Soils enriched by ReGM have increased microbial bioactivity, higher fungal:bacteria biomass, greater functional diversity, and richer microarthropods and macrofauna communities. Vegetation responds inconsistently, with increased, neutral, or decreased total plant diversity, richness of forage grasses and invasive species under ReGM: grasses tend to be favored but shrubs and forbs can be depleted by the mechanical action of hooves. Trampling also reduces numerous arthropods by altering vegetation structure, but creates favorable habitat and food for a few taxa, such as dung beetles. Similarly, grazing-induced structural changes benefit some birds (for foraging, nest sites) while heavy stocking during winter and droughts reduces food for seedeaters and songbirds. With herding and no fences, wildlife (herbivores and predators) thrives on nutritious regrowth while having access to large undisturbed areas. It is concluded that ReGM does not universally promote biodiversity but can be adapted to provide greater landscape habitat heterogeneity suitable to a wider range of biota.

Review: An overview of beef production from pasture and feedlot globally, as demand for beef and the need for sustainable practices increase

Beef is a high-quality source of protein that also can provide highly desirable eating experiences, and demand is increasing globally. Sustainability of beef industries requires high on-farm efficiency and productivity, and efficient value-chains that reward achievement of target-market specifications. These factors also contribute to reduced environmental and animal welfare impacts necessary for provenance and social licence to operate. This review provides an overview of beef industries, beef production, and beef production systems globally, including more productive and efficient industries, systems and practices. Extensive beef production systems typically include pasture-based cow-calf and stocker-backgrounding or grow-out systems, and pasture or feedlot finishing. Cattle in pasture-based systems are subject to high levels of environmental variation to which specific genotypes are better suited. Strategic nutritional supplementation can be provided within these systems to overcome deficiencies in the amount and quality of pasture- or forage-based feed for the breeding herd and for younger offspring prior to a finishing period. More intensive systems can maintain more control over nutrition and the environment and are more typically used for beef and veal from dairy breeds, crosses between beef and dairy breeds, and during finishing of beef cattle to assure product quality and specifications. Cull cows and heifers from beef seedstock and cow-calf operations and dairy enterprises that are mostly sent directly to abattoirs are also important in beef production. Beef production systems that use beef breeds should target appropriate genotypes and high productivity relative to maintenance for the breeding herd and for growing and finishing cattle. This maximizes income and limits input costs particularly feed costs which may be 60% or more of production costs. Digital and other technologies that enable rapid capture and use of environmental and cattle performance data, even within extensive systems, should enhance beef industry productivity, efficiency, animal welfare and sustainability.

Is ground cover a useful indicator of grazing land condition?

Remotely sensed ground cover data play an important role in Australian rangelands research development and extension, reflecting broader global trends in the use of remotely sensed data. We tested the relationship between remotely sensed ground cover data and field-based assessments of grazing land condition in the largest quantitative analysis of its type to date. We collated land condition data from 2282 sites evaluated between 2004 and 2018 in the Burdekin and Fitzroy regions of Queensland. Condition was defined using the Grazing Land Management land condition framework that ranks grazing land condition on a four point ordinal scale based on dimensions of vegetation composition, ground cover level and erosion severity. Nine separate ground cover derived indices were then calculated for each site. We found that all indices significantly correlated with grazing land condition on corresponding sites. Highest correlations occurred with indices that benchmarked ground cover at the site against regional ground cover assessed over several years. These findings provide some validation for the general use of ground cover data as an indicator of rangeland health/productivity. We also constructed univariate land condition models with a subset of these indices. Our models predicted land condition significantly better than random assignment though only moderately well; no model correctly predicted land condition class on >40% of sites. While the best models predicted condition correctly at >60% of A and D condition sites, condition at sites in B and C condition sites was poorly predicted. Several factors limit how well ground cover levels predict land condition. The main challenge is modelling a multidimensional value (grazing land condition) with a unidimensional ground cover measurement. We suggest that better land condition models require a range of predictors to address this multidimensionality but cover indices can make a substantial contribution in this context.

Effect of high-intensity rotational grazing on the growth of cattle grazing buffel pasture in the Northern Territory and on soil carbon sequestration

Context Scientific and anecdotal reports conflict on the effects of intensive rotational grazing (IRG) on cattle growth, and very limited objective data are available from cattle grazing in northern Australia that producers can use to decide whether to adopt IRG. Aims This study aimed to compare liveweight gain and sequestration of soil organic carbon when cattle grazed buffel grass (Cenchrus ciliaris L.) under either continuous grazing (CG) or IRG. Methods In each year of this 9-year study, a cohort of Brahman and Brahman-cross weaners was randomly allocated to IRG and CG treatments. They grazed predominantly buffel pasture at Douglas Daly Research Farm from shortly after weaning for about a year, at which time they were replaced by the next year’s group, and the average liveweight gains of the treatments over the post-weaning year were compared each year for 9 years. Soil organic carbon was measured in the topsoil (0–30 cm) twice each year for 5 years (2009–14) and changes in carbon stocks over time were compared between treatments. Key results In each year of this study, the growth of cattle grazing buffel pasture was lower under IRG than CG. In each year, liveweight gain was lower (P < 0.05) per head and per hectare under IRG. Topsoil soil organic carbon stocks did not increase in the IRG treatment over the 5 years of this study. Conclusions This study found that cattle growth, both per head and per hectare, was lower under IRG than CG, and that IRG did not result in any increase in soil organic carbon over time. Implications The lower per head and per area production from the IRG system, combined with the extra infrastructure and operating costs for IRG systems, make it unlikely that adoption of IRG would improve the profitability of cattle-grazing operations on similar pasture systems in northern Australia. However, the findings of this study may not apply to other pasture systems and environments.

Grazing pressure and tree competition affect cattle performance and native pastures in Eucalypt woodlands of Queensland, north-eastern Australia

Context Well managed grazing pressure will optimise animal and pasture production, and preserve the soil to maintain a viable beef business on native pastures in eucalypt woodlands. Aims A cattle grazing experiment was established to measure animal and pasture performance under management practices used in the Aristida/Bothriochloa native pastures in central Queensland. Methods Performance of Brahman-cross steers and pastures were measured in an experiment with three grazing pressures by two tree densities in a Eucalyptus populnea woodland in north-eastern Australia over 8 years in paddocks of 4–18 ha. Key results At low grazing pressure with trees killed by herbicide (‘cleared’), stocking rate increased 35% as pasture composition and biomass improved over 8 years. At low grazing pressure where treed, stocking rate remained constant, however, at high grazing pressure where treed, it was reduced after 4 years. The annual liveweight gain increased from 0.37 to 0.45 to 0.51 kg/head.day as grazing pressure was reduced from high to medium to low grazing pressure respectively, and across grazing pressures it decreased from 0.49 where cleared to 0.39 kg/head.day where treed. Liveweight gain per hectare increased under low grazing pressure and declined at medium and high pressures. Body condition scores responded positively to lower grazing pressure and a lack of tree competition to pastures. This treatment combination also produced higher animal sale values. Pasture biomass, basal area and ground cover were all affected negatively by increasing grazing pressure. Conclusions Grazing 25% of autumn pasture improved dry matter production, species composition and land condition, and increased steer growth rates, body condition and their market value. This grazing pressure produced an increasing trend in stocking rates relative to the decline at higher grazing pressures. Higher liveweight gain/ha was produced initially at high grazing pressure (75% utilisation), however, after 4 years animal condition and pastures deteriorated, requiring a reduction in stocking rate to maintain the condition of both the remaining animals and the pastures. Managing tree competition to pastures is necessary to maintain the higher animal production potential. Implications This objective information demonstrates the benefits for cattle, pastures and long-term economic outcomes of managing for conservative grazing pressure and controlling tree competition to pasture in this woodland. Applying these findings can improve beef business outcomes and provide management groups with objective educational resources.

Insights on the relationship between total grazing pressure management and sustainable land management: key indicators to verify impacts

Demonstrating sustainable land management (SLM) requires an understanding of the linkages between grazing management and environmental stewardship. Grazing management practices that incorporate strategic periods of rest are promoted internationally as best practice. However, spatial and temporal trends in unmanaged feral (goat) and native (kangaroo) populations in the southern Australian rangelands can result land managers having, at times, control over less than half the grazing pressure, precluding the ability to rest pastures. Few empirical studies have examined the impacts of total grazing pressure (TGP) on biodiversity and resource condition, while the inability to manage grazing intensity at critical times may result in negative impacts on ground cover, changes in pasture species composition, increased rates of soil loss and reduce the ability for soils to store carbon. The widespread adoption of TGP control through exclusion fencing in the southern Australian rangelands has created unprecedented opportunities to manage total grazing pressure, although there is little direct evidence that this infrastructure leads to more sustainable land management. Here we identify several key indicators that are either outcome- or activity-based that could serve as a basis for verification of the impacts of TGP management. Since TGP is the basic determinant of the impact of herbivory on vegetation it follows that the ability for rangeland pastoral management to demonstrate SLM and environmental stewardship will rely on using evidence-based indicators to support environmental social licence to operate.

Grazing pressure impacts on two Aristida/Bothriochloa native pasture communities of central Queensland

Managing native pastures for sustainable and economic production requires a good understanding of grazing effects on pasture dynamics. The Aristida/Bothriochloa pastures of north-eastern Australia are important for cattle production but little data on grazing pressure impacts on pastures are available to guide management decisions of producers, for land management education programs, or for predictive modelling. To address this deficiency, four different continuous grazing intensities were imposed on woodland communities over 7 or 8 years at two sites: a Eucalyptus populnea (poplar box) and a E. melanophloia (silver-leaved ironbark) community. Both sites had replicated paddocks grazed at a low, medium or high grazing pressure by +/− tree killing using herbicide (12 paddocks), and 12 ungrazed (nil grazing pressure) 1-ha plots subjected to the same tree-killing contrasts. Grazed paddock areas were fixed and varied between 3.5 and 21.5 ha. Differential grazing pressures were reset each autumn, by adjusting cattle numbers to consume over the next year the equivalent of 0%, 25%, 50% or 75% of the standing pasture mass available. Pasture grasses suitable as indicators of grazing pressure were identified for both communities. Under low grazing pressure, Themeda triandra (kangaroo grass) was the only desirable grass to show a significant increase in total contribution over time at both sites, although Dichanthium sericeum (Queensland bluegrass) also increased its contribution at the poplar box site. Chloris species increased their contribution as grazing pressure increased. The proportion of less palatable Aristida spp. (wiregrasses) in the pasture was not affected by high grazing pressure, although they increased at low grazing pressure in the poplar box community. There were no consistent changes in native legumes or weedy forb species to any treatment. Increasing grazing pressure had a greater negative effect on pasture mass, ground cover and pasture crown cover area than on changing species composition. Most changes in composition due to grazing pressure were smaller than those associated with variable seasonal rainfall, and were greater in the poplar box community. In above-average rainfall years grazing up to 50% of autumn standing pasture mass had no detrimental effect on composition in treeless poplar box country in the short term. The pastures remained stable or improved in both communities when grazing pressure was set annually to utilise 25% of the standing autumn forage.

Comparison of stocking methods for beef production in northern Australia: seasonal diet quality and composition

Managing and measuring the grazing and nutrition of cattle are required to improve the productivity and profitability of beef businesses in northern Australia. The quality and composition of the diet selected by cattle grazing in three stocking methods (continuous, extensive rotation and intensive (cell) rotation) on nine commercial properties in Queensland were estimated using near infrared reflectance spectroscopy analyses of fresh faeces; 585 faecal samples were analysed between 2005 and 2009. Sites were in two regions (north and south Queensland) and on two vegetation communities, namely brigalow (Acacia harpophylla F. Muell. ex Benth.) on clay soils and eucalypts on light-textured soil types. Pastures were dominated by perennial sown exotic grass species, predominantly Cenchrus ciliaris L. (buffel grass) at five sites and Urochloa mosambicensis (Hack.) (Sabi grass) at one site, and by native perennial tussock grasses at three sites. Seasonal profiles of dietary crude protein, dry matter digestibility, faecal nitrogen concentration, proportion of non-grass, ratio of crude protein to digestibility and an estimate of liveweight gain are presented for each stocking method. Overall, dietary crude protein, digestibility, faecal nitrogen, the crude protein : digestibility ratio and liveweight gain were significantly higher for animals grazed continuously, with short rest periods, than for animals in extensive or intensive rotations. There was a significant interaction between stocking method and pasture growing conditions, measured as a simulated growth index, for dietary crude protein and faecal nitrogen. There was no difference between stocking methods during periods when the index was <0.2, indicating no pasture growth, but during periods of active growth (index >0.5), crude protein and faecal nitrogen were higher with continuous grazing than in the extensive and intensive rotations. For cattle producers considering alternative stocking methods, the results suggest they can obtain similar ecological responses under any of the three methods and diet quality will be higher during the pasture growing period in continuously grazed pastures.