Rotational Grazing Research Articles

Avian Responses to Different Grazing Management Practices in Neotropical Temperate Grasslands: A Meta-Analysis

Bird populations inhabiting the Rio de la Plata Grasslands in southern Brazil, Argentina, and Uruguay are known to be affected by livestock grazing practices. Cattle grazing can lead to changes in bird assemblages by affecting the heterogeneity of vegetation structures. We conducted a meta-analysis using studies that reported bird richness and abundance under different grazing management practices. We compared ranches under continuous grazing management (control, CGM) to (1) ranches under technological inputs management (TIM, herbicides and exotic pastures) and (2) ranches under ecological process-based management (EPM), which include ranches that utilise controlled and rotational grazing. We used random effects multilevel linear models to evaluate grazing regimen impacts. Our results indicate a negative impact of TIM on both bird abundance and richness (mean ± SE: −0.25 ± 0.07 and −0.92 ± 0.10, respectively) since the use of inputs simplifies vegetation structure and results in the loss of ecological niches. Compared to CGM, the influence of EPM on total bird abundance appears to be more dependent on grassland height, as evidenced by a decline in short grasses and increase in tall grasses. Our meta-analysis suggests that EPM practices may be beneficial for the conservation of endangered tall-grass birds.

Lactation curves for milk, fat and protein in dairy cows under regenerative versus conventional farming practices

ABSTRACT Regenerative agriculture aims to utilise more diverse pasture species and enhance animal performance through sustainable soil management and pasture quality. This study evaluated the influence of regenerative and conventional farming on dairy cow performance and milk production under different pasture mixes and management strategies. Monthly herd test records were used to model individual lactation curves for daily milk, fat, and protein yield for the 2022–2023 season using random regression with third-order orthogonal polynomials. Total yields were calculated from predicted daily yield. Treatments were SPCM: Standard pasture under conventional management, DPCM: Diverse pasture mix under conventional management, and DPRM: Diverse pasture mix under regenerative management. Total milk yield was similar across treatments, averaging 3370 kg (SPCM), 3649 kg (DPCM), and 3626 kg (DPRM) for the 2022–2023 season. No significant differences were observed in fat, protein, milk solids yield, or milk composition. Cows on diverse pastures, regardless of management approach, showed heavier liveweights than those on standard pastures. DPCM and DPRM cows averaged 474 kg, significantly greater than SPCM cows at 464 kg (P < 0.0001), likely due to longer grazing rotation and higher post-graze mass. These findings suggest that pasture species diversity, regardless the management, enhances liveweight without affecting milk composition.

Variability in Nutrient Content and Biochemical Parameters of Soil Under Rotational Pasture Management of Farmed Fallow Deer

Fallow deer are animals kept on large-scale pastures, which influence soil properties, including the content of nutrients in the soil and the flow of these nutrients in the soil–plant–animal system. Therefore, the aim of this case study was to analyze the variability in the macronutrient content and biochemical properties of soil under rotational grazing conditions of farmed fallow deer. Fallow deer grazed in two summer pens from April to November, and in the winter pen from December to March. The analyses included the determination of several soil parameters to capture sensitive soil changes and assess potential degradation of the soil environment in response to grazing: pHKCl, TOC, TN, N-NO3, N-NH4+, total (P, K, Mg, Ca, and Na) and available (Pav, Kav, Mgav) forms of macronutrients, and selected soil enzymes (dehydrogenase, acid phosphatase and alkaline phosphatase, and urease). The results showed that the pHKCl in the plots used by farm fallow deer was lower than in the soil of the control object. Moreover, the TN and TOC content in the soils of all pastures was statistically significantly lower than in the soil without grazing, while for TOC, the same effect was observed in the winter pasture soil. The content of N-NO3− was several times higher than that of N-NH4+ in the soils of the studied breeding plots. The relationships noted indicate that grazing is important in the transformation of soil organic matter, which is influenced by the relationship between carbon and nitrogen. In addition, the grazing of farmed fallow deer had a negative effect on the content of P in the soils of all pastures and a positive impact on the accumulation of K. Winter grazing had a positive effect on the amount of Pav and Kav in the soil, but a negative effect on the content of Mgav, compared to grazing in the summer quarters. In the plots used for pastures, the activity of soil enzymes was higher than in the control soil. It has been shown that the influence of fallow deer farming on the soil environment of pastures is not unequivocal. Therefore, long-term monitoring of changes in the properties of these soils is necessary.

Multi-year performance of white clover oversown into eastern North Island hill country

Animal performance on summer-dry North Island hill country pastures is limited by soil fertility and the challenge of establishing and retaining a strong legume base in swards on steeper slopes. However, this can be overcome by 1. selecting legume species adapted to the various slope, aspect and soil type combinations; and 2. following well-recognised establishment and management techniques developed in the 1980s. We broadcast white clover in two large southerly aspect paddocks on Tangihanga Station, Gisborne, in the autumn of 2019. Establishment methods involved resident pasture control by hard grazing and selective herbicide to supress dominant low-fertility grasses, broadcasting at high sowing rates and trampling of seed with sheep. We followed white clover persistence and animal performance over the subsequent 5 seasons of rotational cattle grazing with heifers and steers, in comparison with adjacent unsown paddocks. The cost of establishment was c. $220/ha. White clover abundance remained high throughout the 5 years, between 25-40% of cover, compared with 7-17% in unsown paddocks. This increase in clover content of the pastures translated into both increased stocking rates and per head growth rates, with overall annual LWG increasing by 67-169% depending on season. The investment was paid back within the first year.

Spring growth of lucerne (Medicago sativa L.) after different times of winter defoliation

The aim of this work was to determine if autumn/winter defoliation affected the time of lucerne stem extension in spring. Two experiments were established at the Field Research Centre, Lincoln University. Experiment 1 was established on 01/06/2022 using an existing two year old stand of “Force 4” lucerne. There were four canopy defoliation dates (1/06, 03/07, 17/07, 1/08). Experiment 2 repeated the treatments on the same paddock in the following year on eight defoliation dates (1/5, 15/5, 1/6, 15/6, 3/7, 17/7, 1/8 and 15/8). In both experiments, five stems were marked in each plot and stem height was measured weekly. The start of stem extension was unaffected by canopy defoliation date in either 2022 (P = 0.20) or 2023 (P = 0.17). Initiation of stem extension was triggered by a base photoperiod of 11.1 ± 0.2 h. This meant the thermal time accumulated from final defoliation to the start of stem extension differed among treatments. These results suggest the time of autumn/winter defoliation (the winter clean-up graze) will not affect the time of the first spring grazing, provided the developing basal buds are not removed. All stands reached 150 mm height by mid-September and produced 3.0 t/ha of dry matter by the end of the month. This suggests, grazing of the first paddock at Lincoln should commence in the first week of September to create a staggered start to rotational grazing that can maximise lucerne yield and quality for animal liveweight production.

Modelling E. coli runoff concentrations from sheep and cow grazed pastures in New Zealand: challenges and future research needs

ABSTRACT A model of Escherichia coli concentrations in the runoff from grazed pastures was developed to increase our knowledge and ability to predict the relative impact of both cow and sheep grazing on water quality. Input parameters to the initial model were derived from published data and model outputs were compared with measured E. coli runoff concentration data from both sheep and cow grazed pasture. The model was designed to represent the complexities of year-round rotational grazing farm system. For cow grazing, the model estimated runoff E. coli concentrations in the same order of magnitude as the measured data. However, for sheep grazing, the model underestimated the measured runoff E. coli concentrations by 1.5 orders of magnitude. To understand this negative result, Monte Carlo simulation techniques were used to conduct a sensitivity analysis of the input parameters. This analysis identified that runoff concentrations were highly sensitive to inputs of the E. coli concentrations in the dung and the mobilisation rates of E. coli from the dung. This modelling study demonstrates that significant gaps and uncertainties remain in our understanding and prediction of the mobilisation and transport of E. coli from grazed pasture systems. HIGHLIGHTS Faecal microbial losses from agriculture are poorly understood. A runoff concentration model was developed based on the area of faecal pats. The area-based model appears to work for cow grazed pastures. The area-based model does not work for sheep grazed pastures.

The LTAR Grazing Land Common Experiment at Platte River High Plains Aquifer.

The Long-Term Agroecosystem Research (LTAR) network of the United States Department of Agriculture (USDA) consists presently of 18 sites within the contiguous United States that are managed by the Agricultural Research Service (ARS) and its partners. The LTAR network focuses on developing national strategies for more efficient, resilient, and profitable agricultural production systems, improved environmental quality, and enhanced rural prosperity. The Platte River High Plains Aquifer (PRHPA) LTAR site is managed jointly by the University of Nebraska-Lincoln (UNL) and USDA-ARS and is one of the LTAR sites that conduct research on both integrated cropping and grazing systems. The PRHPA region encompasses multiple land resource areas and diverse agricultural production systems. The PRHPA sites, predominantly located in eastern Nebraska, are designated as an integrated system focused specifically on the region's dominant production practices of row crop (corn and soybean), managed pastures, and beef cattle production. Here, we focus on C3 cool-season smooth bromegrass (Bromus inermis Leyss.) pasture grazing systems under prevailing and alternative management practices for the region. The sites evaluate continuous and rotational grazing with and without pasture fertilization (prevailing practices). In an additional treatment, cattle are supplemented with dry distillers grains plus solubles, while manure supplies fertilization (alternative practice). Main measurements at the site evaluate plant and animal productivity, forage quality, greenhouse gas fluxes, and soil physical, chemical, and biological properties. This paper describes the regional characteristics of the PRHPA site, ongoing LTAR research related to pasture and livestock production, stakeholder engagement, and future research plans.

Mainstreaming Indigenous Knowledge of Pastoralists into Climate Change Policies in Cameroon

Indigenous pastoralists are hardest hit by the impacts of climate change because of their dependence on nature and limited adaptation. This paper seeks to examine the level of integration of traditional knowledge systems into adaptation policies in Cameroon, using the specific case of Mbororo pastoralists in the Western Highlands. Using a mainly qualitative approach in data collection, in-depth interviews were conducted with 28 purposively selected pastoralists from 4 divisions with intense pastoral activity, comprising 19 Mbororo pastoralists, 2 members of the Mbororo Social and Cultural Association (MBOSCUDA), 2 Mbororo traditional rulers, 5 Mbororo women and one focus group discussion. Discussions were recorded and voice notes were transcribed, coded and treated according to content and thematic with the aid of Atlas. Ti software. Results show that Mbororo pastoralists migrated into the region in the 1950s as nomadic herders and occupied marginal lands due to the nature of their activity. With climatic aberrations being acute, their closeness to nature permitted them to develop a wide array of knowledge and traditional practices to adapt and exploit existing opportunities. Semi-nomadic and transhumance methods of rearing, cross-breeding local species with high-breed species to produce resistant breeds of cattle, cultivating resistant pasture species, rotational grazing and using traditional medicines to treat cattle diseases have reduced resource degradation and curbed the effects of climatic aberrations. Nevertheless, these indigenous knowledge systems are eroding fast due to poor indigenous institutions and non-integration into policy. This work will reinforce capacities of decentralized communities in developing and implementing local adaptation plans on climate change.

Fatty acids and secondary metabolites can predict grass-finished beef and supplemental cattle feeds

Beef raised using rotational grazing practices on biodiverse pastures offers potential benefits to animal and environmental health and can improve the nutrient density of meat to favor human health. However, many cattle producers contend with the seasonal unavailability of fresh forage, necessitating the utilization of supplementary feeds or indoor feeding. The objective of this study was to profile secondary metabolites and fatty acids in grass-finished beef supplemented with different feeds (4.5 kg/head/day) and to explore the potential for grass-finished beef authentication. In this two-year study, steers (n = 115) were randomly allocated to one of four diets: 1) pastured/supplemented with hay (control group), 2) pastured/supplemented with baleage, 3) pastured/supplemented with soybean hulls, or 4) baleage/soybean hulls in confinement. Secondary metabolites and fatty acids were measured using UHPLC-MS/MS and GC-MS, respectively. Of the 94 measured metabolites, pyridoxine, alpha-tocopherol, hippuric acid, and gallic acid differed between diets (p < 0.05 for all). Based on random forest classification, beef from the pasture/hay, pasture/baleage, pasture/soybean hulls, and confinement baleage/soybean hulls groups could be identified with a predictive accuracy of 100%, 50%, 41%, and 97%, respectively. Although minimal significant differences were observed, our data indicate that certain supplemental feeds maintain favorable nutritional profiles of grass-finished beef. In addition, metabolomics can predict cattle on exclusively forage-based or feed-based diets with a high degree of certainty.

A multi-objective optimization model to maximize cattle weight-gain in rotational grazing

A multi-objective optimization model to maximize cattle weight-gain in rotational grazing

Response of Species Diversity and Stability of Typical Steppe Plant Communities on the Mongolian Plateau to Different Grazing Patterns

ABSTRACTGrasslands represent a major biome on Earth and play a vital role in ecosystem functioning and dynamics. However, owing to the variations among grassland types, the impact of grazing on plant community diversity and stability remains unclear. This study is based on the typical steppe of the Mongolian Plateau. Field sampling and data analysis were combined to qualitatively and quantitatively investigate the structural characteristics, species diversity, and stability of plant communities under varying grazing intensities, that is, four‐season nomadic, two‐season rotational, and sedentary grazing (FSNG, TSRG, and SG, respectively). The results indicated that FSNG pastures exhibited the largest number of plant species while FSNG and TSRG pastures exhibited relatively high importance values for the primary dominant species. Carex duriuscula, Chenopodium glaucum, and Cleistogenes squarrosa were prominent in SG pastures, with C. duriuscula having the largest importance value. The mean height, cover, and aboveground biomass of plant communities in FSNG were significantly higher than those in SG (p &lt; 0.05), with no significant difference observed between FSNG and TSRG. FSNG also demonstrated the highest Shannon–Wiener, Simpson, and Pielou indexes. The Shannon–Wiener and Simpson indexes between the FSNG, TSRG, and SG pastures showed significant differences (p &lt; 0.05). Nomadic plant communities displayed positive loosely interspecific traits, suggesting independence and positive succession. Conversely, communities in TSRG and SG exhibited negative correlations and higher instability. The stability analysis ranked community stability as FSNG &gt; TSRG &gt; SG, suggesting that judicious grazing practices could enhance grassland stability. The findings reveal that grazing patterns influence plant community composition and function and that FSNG pastures promote higher species diversity, perennial dominance, and overall stability compared with TSRG and SG pastures.

Duration of Cattle Ranching Affects Dung Beetle Diversity and Secondary Seed Removal in Tropical Dry Forest Landscapes.

Cattle ranching is an economic activity responsible for the loss of large extensions of tropical dry forest around the world. Several studies have demonstrated that the use of inadequate practices of this activity in tropical forests (e.g., fire, agrochemicals, and lack of rotational grazing systems of cattle in pastures) have negative consequences on dung beetle diversity and their ecological functions. In the present study, the influence of the cattle ranching duration gradient on the diversity of dung beetles and seed removal was evaluated. This study was carried out in pastures with different times of establishment of cattle ranching (between 4 and 40 years) in a tropical dry forest of Mexico. Overall, the species richness of dung beetles was similar along the gradient of grazing ages. However, the diversity of common (q1) and dominant (q2) species decreased and was associated with an increasing abundance of exotic species and a decreasing abundance of native species. Seed removal was mainly carried out by four beetle species, among which the exotic species Digitonthophagus gazella was the most important. The results establish that the duration of cattle ranching primarily influences the composition of dung beetle communities, as reflected in changes in the structure and function of their assemblages in the pastures. Although native dung beetles persist at low abundances along this gradient, the consequences of land use changes are undeniable in other similar ecosystems where these species could definitively disappear.

Grazing and precipitation addition interactions alleviate dominant species overgrowth and promote community productivity and biodiversity in a typical steppe

Grazing and precipitation are pivotal factors influencing the productivity and biodiversity of grassland ecosystems, largely through their effects on the growth and reproduction of dominant species. Approximately 50 % of terrestrial ecosystems are concurrently affected by grazing and precipitation addition (PA), yet the interactive effects of these factors remain underexplored. To elucidate the combined impacts of grazing and PA on the growth of dominant species and their influence on community structure and function, we initiated a four-year combined grazing and PA experiment based on a long term of grazing experiment in a typical steppe. The synergistic interaction between PA and grazing enhanced canopy diameter (CD), tiller density (TD), and seedling density (SD) in dominant species, while decreasing reproductive branch density (RB). Conversely, an antagonistic interaction increased plant height (PH) and TD but reduced SD. These responses suggest that dominant species adapt to combined grazing and PA pressures by shifting growth strategies towards lateral growth and asexual reproduction. The growth characteristics of dominant species exhibited four response patterns to grazing and PA interactions: full saturation, sufficient saturation, equal saturation, and deficit saturation, each with three corresponding thresholds: adaptation, optimum, and saturation points. Grazing decreased the precipitation response thresholds for PH, CD, RB, and population density, while increasing the optimal points for TD and SD. These changes in the growth of the dominant species resulted in a 33 % reduction in the aboveground biomass (AGB) of the community and triggered a 18 % increase in the coupling index between AGB and species richness within the community. Our findings highlight the role of dominant species in facilitating community adaptation to increased precipitation and rotational grazing, offering critical insights for developing sustainable grazing strategies under climate change.

Different groups’ grazing technique preferences in the Miombo woodlands of Eastern Tanzania

Grazing in Miombo woodlands is essential for the livelihoods of the pastoral and agropastoral communities that live adjacent to these fragile ecosystems. However, Miombo woodlands offer not only fodder for livestock but also fertile land for crop farming; hence, they are equally important to the farmers residing in these areas. Due to the importance of the Miombo woodlands for the livelihoods of several groups, the consumption of and competition for Miombo resources has increased over time and now threatens the overall health of the ecosystem. This study aimed to identify the grazing techniques practiced by different livelihood groups in Miombo woodlands; their preferences for different practices, as well as the factors that influence these preferences, so as to understand how sustainable grazing can be achieved for better ecosystem health. The study was conducted in Handeni, Kilombero, and Kilosa districts and covered pastoralists, agropastoralists, and farmers. We carried out focus group discussions, key informant interviews, and a survey of 246 respondents. Un-patterned rotational grazing was the most preferred grazing technique by all three groups, and the only technique the three groups shared a preference for. All the groups took a neutral stance in relation to continuous grazing. Their preferences for other grazing techniques differ. The study highlights the need to raise awareness amongst pastoralists about land ownership and management and recommends enhancing land property rights for all groups in order to harmonize livestock keeping and other land uses for achieving sustainable grazing and overall ecosystem health in the fragile Miombo woodlands of Tanzania.

417 Impact of virtual fence technology on yearling steer behavior and performance

Abstract Virtual fencing (VF) has the capacity to transform the landscape of livestock management within extensive rangeland systems. The objective of this study was to evaluate the effect of Vence (Merck &amp; Co., Inc., Rahway, NJ) VF technology on yearling steer behavior and performance. Steers were allocated into one of two grazing systems [continuous grazing (CG) or rotational grazing (RG) managed using VF] across three different stocking rates (light, moderate, and heavy, 0.32, 0.40, and 0.72 animal unit months, respectively) for three grazing seasons. Based on initial body weight, steers were randomly blocked into six pastures (346 ± 39, 273 ± 34, and 319 ± 29 kg, respectively) at the South Dakota State University Cottonwood Field Station (n = 127, 135, and 127, in 2021, 2022 and 2023, respectively). Steers assigned to the CG treatment had free access to the entire pasture for the duration of the grazing season. Steers assigned to the RG treatment were rotated among virtual ‘paddocks’ for the duration of the grazing season. The days spent grazing in each paddock for the RG treatment were determined based on bi-weekly clip plots for biomass estimation. The VF collars were used to track steer location at 5-min intervals; only steers assigned to the RG treatment were managed with VF boundaries and exposed to auditory and electrical cues from the collars. Raw data was downloaded from Vence Herd Manager through an automatic programming interface and cleaned by removing messages that failed to transmit correctly or were outside the bounds of study site pastures. Animal behavior metrics of daily distance traveled (DDT), daily grazing time, daily resting time, and daily walking time were calculated for each individual animal and averaged by pasture using Program R. Steer weights were collected using SmartScales (C-Lock Inc, Rapid City, SD). Average daily gain (ADG) was calculated using a linear model to develop a regression equation for each individual animal using weight as the dependent variable and day of trial as the independent variable. The slope of the regression line was used to estimate ADG. Individual DDT, behavior, and performance metrics were analyzed using a mixed model analysis of variance (ANOVA) to compare the impact of grazing treatment and stocking rate (fixed effects) with year as the random effect. Treatment did not influence (P &amp;gt; 0.05) grazing, walking, or resting behavior. Similarly, no differences were detected in DDT between treatment groups or across different stocking rates. Furthermore, there were no differences (P &amp;gt; 0.05) in ADG across treatment groups. Implementation of VF had no impact on animal behavior or performance, justifying its use in grazing settings; however, financial and cattle finishing aspects still need to be evaluated to determine its overall benefits and costs.

454 Evaluating the effects of grazing native rangeland on enteric emissions

Abstract Understanding beef cattle enteric emissions on extensive western U.S. rangeland systems is critical for implementing sustainable grazing practices that reduce greenhouse gas (GHG) emissions. These practices must also improve livestock and plant productivity and climate resiliency while maintaining or reducing production costs. However, enteric emissions of grazing cattle under different stocking rates and grazing management strategies are largely unknown for western U.S. rangelands. Thus, our objective was to evaluate the differences in enteric emissions of stocker steers grazing native rangeland. Yearling Angus steers (n = 127) were stratified by initial body weight (BW) to six groups, then randomly assigned to one of six pastures grazed from June to September 2023 at the South Dakota State University Cottonwood Field Station (Cottonwood, SD) as part of a long-term stocking rate trial (80+ yr). Each pasture was equipped with a GreenFeed (C-Lock Inc, Rapid City, SD) pasture system to measure individual animal CH4 and CO2 emissions for continuous grazing (CG) and rotational grazing (RG) strategies in three stocking rates (Light, Moderate, and Heavy, 0.32, 0.40, and 0.72 animal unit months, respectively) in a 2 x 3 factorial design. Differences in enteric emissions among stocking rate and grazing strategy were analyzed using a linear mixed effects model in R, using the lme4 package, with animal as a random effect, and a post-hoc contrast among treatments was assessed using the lsmeans package. Steer initial and final BW were similar (P &amp;gt; 0.05) among treatments. For CH4 emissions, there was a significant interaction between stocking rate and grazing strategy (P &amp;lt; 0.05). Specifically, CH4 emissions for moderate-RG (195 ± 4.3 g/d) were less than those from heavy-CG (221 ± 4.5 g/d) and light-RG (221 ± 4.7 g/d) over the study period (P &amp;lt; 0.05). For CO2 emissions, light-CG steers respired greater CO2 emissions (6892 ± 101 g/d) than heavy-RG (6398 ± 107 g/d; P &amp;lt; 0.05). All other treatment lsmeans were similar (P &amp;gt; 0.05) and intermediate to these treatment effects. The assessment of GHG emission values for cattle grazing native rangeland is essential for informing climate mitigation strategies, improving animal efficiency, and understanding changes in GHG emissions over production phases and across animal classes.

456 Allocating distribution of pasture utilization across the grazing landscape in grazing steers equipped with virtual fencing collars

Abstract Spatial utilization of pasture landscapes by grazing animals is often heterogeneous and driven by complex environmental and physiological interactions between plants and animals. Synergistic energy pathways can be modeled using mechanistic relationships describing resource distribution, animal behavior, metabolic energy rate, and pasture utilization using biometric sensors. The objective of this study was to demonstrate the ability to measure the energy landscape by mapping fine-scale contributions to animal energy expenditure, nutrient acquisition, growth, and overall economic profitability. We utilized animal trajectories and location fixes recorded by virtual fencing collars (Vence) daily body weight (BW) using precision livestock scales (Smartscale, C-Lock Inc.) and oxygen consumption (GreenFeeds, C-Lock Inc.) on steers (n = 127), managed as part of a broader project to evaluate environmental synergies in extensive grazing systems. Steers were allocated to one of six native grass pastures assigned to either rotational or continuous grazing strategies, and one of three stocking rates (low, moderate, high) in a 2 x 3 factorial arrangement. Space utilization was quantified as the frequency of fixes located within each cell of a 5 x 5-meter Grid and the distance between grid cells and water was calculated using the Pythagorean theorem. Movement behavior was quantified using Program R to calculate step length, the distance between two temporally continuous fix points utilizing the Pythagorean Theorem, and turn angles calculated as the cosine of the pre- and pro-ceeding step lengths where larger values indicated greater deviation from a straight trajectory. A mixed linear regression model was fitted using the lmer function in the lme4 package. Space utilization decreased with increased distance from water (P &amp;lt; 0.05), with rotational grazing strategies increasing concentration around water sources (P &amp;lt; 0.05). This indicates an opportunity to utilize precision livestock technology to facilitate pasture management and increase space utilization in grazing cattle.

416 Implementation of virtual fencing in heifers for mountain summer grazing

Abstract A virtual fencing (VF) system is based on a smartphone application that defines an invisible grazing boundary based on global positioning. Animals are tracked via GPS collars. When reaching the virtual boundary, the collar emits an ascending audio tone, followed by a mild electric pulse (0.2 Joule) when crossing it. The technology is particularly promising in rough and extensive mountainous areas where physical fencing is difficult and more time-consuming. Environmental conditions may also affect the functionality of the VF system, with potential impacts on animal behavior. Therefore, the present study tested a VF system on 30 female heifers in a rotational grazing system on Swiss mountain pastures (approximately 1,300 to 1,500 m above sea level). Each heifer was equipped with a VF collar (Nofence AS, Batnfjordsør, Norway) for individual recording of audio tones and electric pulses. After two wk of VF training in the lowlands (approximately 700 m above sea level), during which the heifers learned to interpret the VF signals correctly, they were transported to the mountain pasture. For mountain grazing, the herd was divided into three groups of 10 heifers each, balanced for age (mean ± SD: 11.9 ± 1.6 mo) and breed (Holstein-Friesian, Montbeliarde, crossbreeds). The outer perimeter of the mountain pasture was surrounded by an electric fence. Its inner area was divided into 3 electrically fenced and 6 virtually fenced paddocks. For 83 d, all groups grazed simultaneously in separate paddocks and rotated sequentially through the 9 paddocks. Video cameras were placed along the virtual fences to record animal responses after receiving audio tones or electric pulses. Moreover, grass height was measured using a rising plate meter to estimate forage availability in the currently grazed paddocks. Throughout mountain grazing, each heifer received an average of 4.9 ± 6.9 audio tones and 0.3 ± 0.7 electric pulses per day. Generalized mixed-effects models revealed that the number of audio tones and electric pulses did not change over grazing periods or among days after paddock change. Behavioral responses of the animals were less pronounced once the heifers had learned the VF system. In addition, grazing interruptions after receiving an audio tone or electric pulse were shorter during mountain grazing compared with the training period (P &amp;lt; 0.001). Furthermore, lower grass heights (P &amp;lt; 0.05) as well as the occurrence of (common but) unpredictable events (P &amp;lt; 0.001), such as the presence of wildlife (e.g., lynx, deer) or neighboring cattle, increased the number of audio tones and electric pulses during mountain grazing. The VF system was still effective in keeping the heifers within their assigned paddocks under mountainous conditions. However, a well-considered handling when changing paddocks as well as a careful placement of the virtual fence is essential to avoid negative effects on the animals.

371 Applying precision rangeland grazing management systems in western South Dakota

Abstract Western rangelands represent approximately 58% of the total arable land in the U.S. and are used primarily for cow-calf production, which has the largest greenhouse gas (GHG) emission footprint of all beef production phases. Further, beef production sustainability concerns involve climate mitigation (reducing GHG output) and adaptation (climate-resilient soil-plant-animals). Precision livestock farming (PLF) may help address sustainability concerns by providing innovative solutions and new opportunities for extensive rangeland production. The use of precision measurement and management tools with precision system models can connect measurement data to inform management capabilities. For example, real-time individual weighing and remote sensing (precision measurement tools) can be used to inform and implement dynamic rotational grazing management using virtual fencing technology (precision management; Menendez et al., 2022, 2023). Recent USDA investment in climate-smart agriculture (CSA) commodities has provided over $3 billion in funding to implement practices to reduce GHG emissions in agriculture production, for which PLF may be one approach to accomplish these goals. The overall purpose is to develop commodities produced using NRCS climate-smart practices (e.g., prescribed grazing, 528) and document reductions to provide market opportunities associated with inset GHG. Currently, South Dakota State University is leading two simultaneous programs, which include precision ranching (virtual fencing, precision weighing, and GHG evaluation) and a beef and bison CSA program (GHG evaluation; 7 producer-owned research ranches, representing more than 1.09 million ha). The scale of the CSA program has revealed that current PLF research has only been a prelude to providing the precision tools necessary to successfully implement CSA practices and document their impact through monitoring, measuring, reporting, and verification (MMRV). This presentation will include rangeland grazing case studies that cover the application of virtual fencing, animal location, behavior tracking, remote sensing, precision weighing, feeding, supplementation, and enteric emissions and soil moisture monitoring on extensive rangelands. Case studies will include an overview of big data processing and precision system model development methods. Increasing awareness of available PLF tools for optimizing grazing management, animal performance, productivity, and associated challenges (maintenance, costs) is essential for meeting livestock and sustainability goals. PLF and data-driven approaches aid in the creation of scalable, cost-effective MMRV protocols and models (soil carbon and enteric GHG) for extensive rangelands (20 to 70,000 ha areas) that allow producers to realize potential CSA market incentives. Further, MMRV will likely help guide management decisions by identifying CSA strategies that build climate-resilient landscapes for sustainable livestock production and other environmental synergies (soil microbiome, bird and insect habit, water retention).

Dynamics of Mulatto Grass Regrowth Depending on Rotational Cattle Grazing Management

This study was carried out to characterize the dynamics of forage accumulation during the regrowth of Mulatto grass submitted to rotational grazing strategies. The treatments corresponded to combinations between two pre-grazing conditions (95% and a maximum light interception during regrowth—LI95% and LIMax) and two post-grazing conditions (post-grazing heights of 15 and 20 cm), according to a 2 × 2 factorial arrangement and randomized complete block design, with four replications. Rates of leaf growth (LGR), stems growth (SGR), total growth (TGR), leaf senescence (LSR), grass accumulation (GAR) (kg·ha−1·day−1), and the senescence/canopy growth ratio during different stages of regrowth. There was no difference between the management strategies for TGR. However, a higher GAR was reported for pastures managed with LI95% relative to LIMax, of 161.7 and 120.2 kg DM ha−1·day−1, respectively. Pastures managed with LI95% have a lower SGR in the intermediate and final regrowth period, reflecting the efficient control in the stalks production. On the other hand, in pastures managed, the LIMax showed higher SGR and LSR in the final regrowth phase. Thus, the LAI was higher in pastures managed at LI95% compared to those managed at LIMax, of 163.9 and 112.7 kg DM ha−1·day−1, respectively. Mulatto grass pastures, which were managed at LI95% pre-grazing, corresponded to approximately 30 cm in height, showed higher LAI, and ensured a low SGR throughout the regrowth period, constituting a more efficient management strategy.