Livestock integration in conservation agriculture.

Grazing livestock have been presented as an unsurmountable obstacle for Conservation Agriculture (CA) in Africa, because they consume organic cover. But grazing livestock can also make positive contributions to CA, while, if properly managed, sufficient organic cover can be left for soil erosion control and soil health improvement. Urine and manure improve soil fertility and soil health, and increase the agronomic efficiency of fertilizer nutrients. Grazing livestock increase options for crop diversity, such as crop rotations with perennial forages, increased use of cover crops and tree-crop associations. Further, as crop yields improve through application of sustainable intensification methods, greater amounts of above-ground residue become available for livestock nutrition, while greater quantities of below- and above-ground plant residues can be left to improve soil health than are currently returned to the soil. At the same time, in areas where extensive systems are still common, greater amounts of crop residue can be left for soil function because alternative feed sources are available. More research and education on proper integration of livestock in CA in the African context, and successful models of pastoralist-crop farmer collaboration are needed, so both livestock and soil needs can be met.

Climatic factors influencing New Zealand pasture resilience under scenarios of future climate change

New Zealand’s intensively managed pastoral agricultural systems are vulnerable to climate change because of their dependence on grazing livestock and pasture as the primary feed supply. Drawing from recent modelling results, annual pasture yields in New Zealand are projected to be robust to a changing climate due to more favourable growing conditions in winter and early spring and increased plant efficiencies from the CO2 fertilization effect. However, growth is also expected to become more variable and unpredictable, particularly in water-limited regions. A combination of short-term, incremental changes (already part of current practice) and longer-term strategic interventions will be necessary to maintain consistent feed supply under future climate change.

Asexual Epichloë Fungi—Obligate Mutualists

Asexual Epichloë are obligate fungal mutualists that form symbiosis with many temperate grass species, providing several advantages to the host. These advantages include protection against vertebrate and invertebrate herbivores (i.e., grazing livestock and invertebrate pests, respectively), improved resistance to phytopathogens, increased adaptation to drought stress, nutrient deficiency, and heavy metal-containing soils. Selected Epichloë strains are utilised in agriculture mainly for their pest resistance traits, which are moderated via the production of Epichloë-derived secondary metabolites. For pastoral agriculture, the use of these endophyte infected grasses requires the balancing of protection against insect pests with reduced impacts on animal health and welfare.

Reconnecting Grazing Livestock to Crop Landscapes: Reversing Specialization Trends to Restore Landscape Multifunctionality

Closely integrated crop and livestock production systems used to be the rule in agriculture before the industrial revolution. However, agricultural landscapes have undergone a massive intensification process in recent decades. This trajectory has led to uniform landscapes of specialized cropping systems or consolidated zones of intensive livestock production. Loss of diversity is at the core of increasing side effects on the environment from agriculture. The unintended consequences of specialization demand the reconciliation of food production with environmental quality. We argue that the reconnection of grazing livestock to specialized crop landscapes can restore decoupled biogeochemical cycles and reintroduce the necessary complexity to restore ecosystem functioning. Besides, the reconnection of crops and livestock promotes several ecosystem services underlying multifunctionality. We focus on the capacity of integrated crop-livestock systems to create biophysical and socioeconomic resilience that cope with weather and market oscillations. We present examples of redesigned landscapes that leverage grazing animals to optimize food production per unit of land while mitigating the externalities of specialized agriculture. We also debate mindset barriers to the shift of current specialization trends toward the design of multifunctional landscapes.

184 Statistical Analysis of Grazing Research

Research in the area of pastures, forages, and grazing livestock has a storied history within the realm of statistical analysis. Unlike traditional experiments in ruminant nutrition, in which an animal is fed individually and data are collected to assess the applied treatment, research on the grazing animal presents its own unique set of challenges. The collection of data on multiple scales (e.g., animal, pasture, landscape, time) brings into question the appropriate assignment of the experimental unit, and variance and covariance estimates must account for both the spatial and temporal effects of the environment. Oftentimes, the designs, assumptions, and rules-of-thumb taught to us in graduate school do not meet muster to adequately address the intricacies of this situation. This presentation will seek to address these complications and present statistically-sound solutions to obtain the maximum information from experimental data. First, a historical examination will be offered of how grazing experiments were originally handled. Next, conjecture will be offered as to why these methods may not remain valid and how advances in computing power and statistical theory allow us to obtain more information from the experiment. Finally, solutions to common scenarios will be offered whereby a more adequate or complete description of the experiment may be obtained.

187 Forage Agronomists Are Needed in Animal Science Departments

Ruminants serve a valuable role in sustainable agricultural systems, specifically in the conversion of renewable resources from grasslands, pasture, and other by-products into edible human food. Recognizing forage and grasses are grown on 25% of arable land, suitable agronomic practices for grazing livestock are necessary to minimize water and soil erosion. Demographics of Animal Science students have changed over the last several years with more students from urban backgrounds and with interests other than traditional animal agriculture. This makes continued emphasis on education programs supporting the grazing livestock industry that much more important. However, for many reasons, universities place less emphasis on training Ph.D. students in forage agronomy. Based on an email survey of 10 land grant institutions, typically one M.S. student/yr and one Ph.D. student/3–4 yr graduates with an advanced degree in forage agronomy. Most departments have experienced dramatic budget reductions. Challenges with funding faculty positions outside of a department’s emphasis area typically results in the question “Should forage agronomy students be trained in Departments of Animal Science or Crop/Soils Science?” It could be argued that either department is the best fit. Forage agronomy requires training in the basics of plant and soil science, but the application of those sciences relate more to animal science and animal production than to traditional crop production such as cereal grains. Departments of Animal Science must communicate the meaningful context of forage agronomy in an active learning environment developing students’ ability to critically think and solve problems. Those providing technical expertise to livestock producers can no longer make recommendations based solely on production efficiency and profitability. Instead, best management practices must include the impact of grazing livestock on the environment. Cooperative agreements between departments should be discussed to adequately support student development in this critical subject matter.

Antagonism to Plant Pathogens by Epichloë Fungal Endophytes—A Review

Epichloë is a genus of filamentous fungal endophytes that has co-evolved with cool-season grasses with which they form long-term, symbiotic associations. The most agriculturally important associations for pasture persistence for grazing livestock are those between asexual vertically transmitted Epichloë strains and the pasture species, perennial ryegrass, and tall fescue. The fungus confers additional traits to their host grasses including invertebrate pest deterrence and drought tolerance. Selected strains of these mutualistic endophytes have been developed into highly efficacious biocontrol products and are widely utilized within the Americas, Australia, and New Zealand for pasture persistence. Less publicized is the antagonism Epichloë endophytes display towards multiple species of saprophytic and pathogenic microbes. This opinion piece will review the current literature on antimicrobial properties exhibited by this genus of endophyte and discuss the reasons why this trait has historically remained a research curiosity rather than a trait of commercial significance.

Do Livestock Injure and Kill Koalas? Insights from Wildlife Hospital and Rescue Group Admissions and an Online Survey of Livestock–Koala Conflicts

Koala populations in Australia are declining due to threats such as chlamydiosis, wild dog predation and vehicle collision. In the last decade, grazing livestock emerged anecdotally as a threat to koala survival in areas where koala habitat and livestock grazing land overlap. This is the first study investigating the significance of livestock-inflicted injuries and deaths in koala populations over a large spatial and temporal scale. We investigated the outcome, scale, and frequency of livestock–koala incidents via an online survey and analysed koala admission records in Queensland wildlife hospitals and a wildlife rescue group (Wildlife Victoria) in Victoria. The results provide evidence of both livestock-inflicted injuries and deaths to koalas, especially as these have been confirmed by witness statements. The outcomes for the koala victims of the incidents were severe with a 75% mortality rate. The reported frequency of livestock–koala incidents was low but increasing, with 72 cases (0.14% out of 50,873 admissions) in Queensland wildlife hospitals during 1997–2019, and 59 cases (0.8% of 7017 rescue records) in Wildlife Victoria during 2007–2019. These incidents were likely to be under-reported due to the remoteness of the incident location, possible mis-diagnoses by veterinarians and the possible reluctance of farmers to report them. Future research is encouraged to explore the mechanics and causes of livestock–koala incidents and to develop management strategies to minimise the livestock threat to koalas.

Global Rangeland Primary Production and Its Consumption by Livestock in 2000–2010

Livestock grazing occupies ca. 25% of global ice-free land, removing large quantities of carbon (C) from global rangelands (here, including grass- and shrublands). The proportion of total livestock intake that is supplied by grazing (GP) is estimated at >50%, larger than the proportion from crop- and byproduct-derived fodders. Both rangeland productivity and its consumption through grazing are difficult to quantify, as is grazing intensity (GI), the proportion of annual aboveground net primary productivity (ANPP) removed from rangelands by grazing livestock. We develop national or sub-national level estimates of GI and GP for 2000–2010, using remote sensing products, inventory data, and model simulations, and accounting for recent changes in livestock intake, fodder losses and waste, and national cropland use intensities. Over the 11 study years, multi-model average global rangeland ANPP varied between the values of 13.0 Pg C in 2002 and 13.96 Pg C in 2000. The global requirement for grazing intake increased monotonically by 18%, from 1.54 in 2000 to 1.82 Pg C in 2010. Although total global rangeland ANPP is roughly an order of magnitude larger than grazing demand, much of this total ANPP is unavailable for grazing, and national or sub-national deficits between intake requirements and available rangeland ANPP occurred in each year, totaling 36.6 Tg C (2.4% of total grazing intake requirement) in 2000, and an unprecedented 77.8 Tg C (4.3% of global grazing intake requirement) in 2010. After accounting for these deficits, global average GI ranged from 10.7% in 2000 to 12.6% in 2009 and 2010. The annually increasing grazing deficits suggest that rangelands are under significant pressure to accommodate rising grazing demand. Greater focus on observing, understanding, and managing the role of rangelands in feeding livestock, providing ecosystem services, and as part of the global C cycle, is warranted.