Grazing Distribution Research Articles

Effects of continuous drone herding on behavioral response and spatial distribution of grazing cattle

Robotic herding is expected to become a new technology for the management of grazing animals. We investigated the behavioral responses of cows to drone herding on consecutive days and the potential of this technology to manipulate grazing distribution in a pasture. A herd of ∼30 cows was stocked in a 1.1-ha pasture for 5 consecutive days each month from May to October 2022. The cows were herded using a drone for 10 days during the grazing period in August (days 1–5) and September (days 6–10). The pasture was divided into nine plots, with two and three plots assigned as the ‘herding area’ in August and September, respectively. When the cows were grazing in the herding area, the operator maneuvered the drone to move the animals out of the area. The drone first approached at an altitude of 10 m; if the cows did not move away, the altitude was gradually lowered to 3 m. The behavioral responses to the drone, success or failure of herding (whether the cows left the area or not), and drone altitude were classified based on videos recorded during herding. The behavior and location of the cows in the pasture were observed during this period. The utilization rates of the plots (percentage of grazing time) were calculated to evaluate the effects of herding and the number of herding days. The cows responded in 59% and 46% of the cases on days 1 and 2, respectively. Startle behavior was recorded in 23% of the responses on day 1. Herding was successful in 51–75% of the cases on days 1–3. However, these percentages decreased thereafter. The utilization rate of the herding area on day 1 was approximately half that on days without herding. It increased from day 2, and almost no effect on grazing distribution was observed on or after day 3. These findings suggest that the cows exhibited little fear of drones after 1-day herding, and responses to the drones decreased as the animals subsequently became habituated to frequently repeated stimuli. Even after a 24-day interval, responsiveness to drone herding barely recovered and then declined. Therefore, drone herding was hardly effective in manipulating grazing distribution. Further investigation of stimulation that persistently elicits desirable responses is needed for future applications in technologies for the autonomous control of animal movement.

Adaptive, multi-paddock, rotational grazing management alters foraging behavior and spatial grazing distribution of free-ranging cattle

Sustainable management of grazinglands depends upon understanding how management practices influence livestock movements in space and time. We conducted a ranch-scale (2,600-ha) social-ecological experiment to examine how foraging behavior of cattle differs between a single large herd rotated adaptively among paddocks (collaborative, adaptive rangeland management; CARM) versus continuous, season-long grazing of paddocks by small non-rotational herds (traditional rangeland management; TRM). We analyzed how differences in cattle movement patterns may be linked to reductions in cattle growth rates and diet quality in the CARM treatment, relative to TRM. Cattle in the CARM treatment exhibited more linear grazing pathways, moved at lower velocity while grazing, and exhibited longer grazing bouts early in the growing season compared to TRM cattle. Grazing time within any given 10 × 10 m area was distributed more unevenly across TRM vs. CARM paddocks in years with average or above-average precipitation, but not in dry years. In all years, areas of high and low grazing intensity were more spatially clustered in TRM than CARM paddocks. Movement patterns of cattle managed using adaptive, multi-paddock rotations at high stock density (CARM) are consistent with less selective foraging. Such cattle form a “grazing front” that moves across the paddock and distributes grazing pressure in a more spatially homogeneous fashion. In years with substantial forage production, TRM cattle spent more time than CARM cattle in preferred areas of the paddock and foraged in more circular patches. In dry years, however, both treatments resulted in similarly even grazing distribution, likely due to limited intra-paddock variation in forage quality and quantity. At the ranch scale, these different intra-paddock movement patterns led to reductions in animal growth rates and no overall effect of grazing management on forage production.

Assessing Livestock Grazing Distribution in Communal Rangelands of the Eastern Cape, South Africa: Towards Monitoring Livestock Movements in Rangelands

In the past, rangelands were managed in a semi-nomadic manner, where pastoralists would distribute livestock to different parts of the rangeland depending on the availability of forage. However, understanding how livestock use rangelands has not been a subject of many studies as the devices to monitor livestock were not available. The objective of this study was to assess livestock grazing distribution in communal rangeland of the Eastern Cape in South Africa in order to improve livestock grazing. The study used Global Positioning Systems (GPS) that were placed on six animals including three sheep and three cattle, selected randomly from participating households. The GPS collars recorded the geographic position of the areas where animals were grazing, at five-minute intervals during the wet and dry season. Grass species composition was surveyed using line transects on areas where livestock grazing occurred. The study further identified three production domains, which were separated by bound polygons on Google Earth Pro to extract MODIS EVI where livestock grazing occurred. Livestock grazing distribution was analysed using T-LoCoH installed in R. The results revealed that both sheep and cattle spent most of their time grazing in areas associated with human features. The dominant grass species were Hyperrenia hirta and Eragrostis plana, suggesting a negative impact of the current livestock grazing distribution. Possible explanations of the current grazing distribution might be that these areas are close to homesteads and provide grazing lawns that contain a high nitrogen content. This study will help in providing an informed basis for the development of South African communal rangeland policies for effective livestock management.

Preliminary study on the application of robotic herding to manipulation of grazing distribution: Behavioral response of cattle to herding by an unmanned vehicle and its manipulation performance

Robotic herding is attracting attention as a new technology for managing grazing animals. As a preliminary step toward the application of robotic herding to the manipulation of grazing distribution, we investigated the behavioral responses of cattle to herding by an unmanned vehicle and its performance in manipulating grazing distribution in a pasture. A herd of approximately 30 cows was stocked in a 1.1-ha pasture for 5 days each month from May to October 2021. The cows were herded by a small unmanned ground vehicle for 7 days of the periods. The pasture was divided into nine plots, with one–four plots assigned as the herding area. When the cows grazed in the herding area, the operator maneuvered the vehicle using a transmitter to move them out of the area. The initial reaction (walk away, appear startled, appear interested, back away, or ignore) to the approaching vehicle, flight distance (within one cow-length or more), whether cows escaped from the vehicle or not, and escape gait (walk or run) were classified based on videos recorded during herding. The behavior and location of the cows were observed at 5 min intervals during the time in the pasture. Utilization rates (percentage of grazing time) of the plots were compared with those on days without herding. Throughout the survey, cows initially walked away from the approaching vehicle in 78% of the cases, the flight distance was within one cow-length in 89%, cows escaped from the vehicle in 93%, and when escaping, they walked in 91%. On the first day of herding, these occasions were less frequent (58%, 83%, 84%, and 82%, respectively), but increased on the second day and remained high thereafter. These findings suggest that cows were able to adjust to herding by an unmanned vehicle within a day and respond to the vehicle desirably for the manipulation of grazing distribution with little fear, irritation or discomfort. One-plot herding decreased the use of the herding area from 10.5% to 3.3% (P = 0.001). Two-plot herding decreased the use from 22.3% to 10.4% (P = 0.015) and increased the use of the least-utilized plot from 8.2% to 14.5% (P = 0.021). These findings indicate that robotic herding by an unmanned vehicle has the potential to positively manipulate grazing distribution.

The glutamate metabotropic receptor 5 (GRM5) gene is associated with beef cattle home range and movement tortuosity

BackgroundThe grazing behaviour of herbivores and their grazing personalities might in part be determined genetically, but there are few studies in beef cattle illustrating this. In this study, we investigated for first time the genetic variation within a candidate ‘grazing gene’, the glutamate metabotropic receptor 5 gene (GRM5), and tested associations between variation in that gene and variation in grazing personality behaviours (GP-behaviours) displayed by free-ranging cows during winter grazing in the steep and rugged rangelands of New Zealand. Mature beef cows (n = 303, from 3 to 10 years of age) were tracked with global positioning system (GPS) and, with 5-minutes (min) relocation frequency, various GP-behaviours were calculated. These included horizontal and vertical distances travelled, mean elevation, elevation range, elevation gain, slope, home range and movement tortuosity, variously calculated using daily relocation trajectories with repeated measurements (i.e., 7 to 24 days (d)) and satellite-derived digital elevation models (DEM). The different GP-behaviours were fitted into mixed models to ascertain their associations with variant sequences and genotypes of GRM5.ResultsWe discovered three GRM5 variants (A, B and C) and identified the six possible genotypes in the cattle studied. The mixed models revealed that A was significantly associated with elevation range, home range and movement tortuosity. Similarly, GRM5 genotypes were associated (P < 0.05) to home range and movement tortuosity, while trends suggesting association (P < 0.1) were also revealed for elevation range and horizontal distance travelled. Most GP-behaviour models were improved by correcting for cow age-class as a fixed factor. The analysis of GP-behaviours averaged per cow age-class suggests that grazing personality is fully established as beef cows reached 4 years of age. Home range and movement tortuosity were not only associated with GRM5 variation, but also negatively correlated with each other (r = − 0.27, P < 0.001).ConclusionsThere seems to be a genetically determined trade-off between home range and movement tortuosity that may be useful in beef cattle breeding programmes aiming to improve the grazing distribution and utilisation of steep and rugged rangelands.

Microhabitat and patch selection detection from GPS tracking collars of semi-free ranging Mashona cattle within a semi-arid environment

Over the last 30 years, the global positioning system (GPS) tracking collars have significantly enhanced livestock grazing behavior studies. Practices designed to understand and improve livestock grazing distribution can now be accurately and cost-effectively monitored with GPS tracking. The behavior and spatiotemporal microhabitat selection of Mashona cattle relative to the season in a semi-free-range grazing system was evaluated using a low‐cost GPS herd activity monitoring (GPSHAM) collar. The GPSHAM automatically logged the position of the lead cow at 20-second intervals over a 7–hour daily grazing period. Additionally, the GPS data was complemented by visually observing the lead cow during daylight hours for nine successive days each in winter (July – August) and summer (February – March) of 2017. Summer and winter tracks were used to identify the Mashona cattle preferred grass species and hotspot areas by identifying the concentration of the GPS generated tracks and points (n ≥ 30) in each grid and were used to calculate the distance from the water source using the shortest distance to the water point from the hotspot patch (HSP). The activities of the lead cow were recorded at five-minute fixed intervals for every 60 minutes in the morning (09:00 – 10:00 hrs), afternoon (13:00 – 14:00 hrs), and evening (16:00 – 17:00 hrs). The percentage of the observation time spent on an activity for the observed animal was calculated for the duration of the observation. Results showed a significant difference in patch selection (p < 0.05) between summer and winter with 17 HSPs being identified in summer and 8 HSPs in winter. Again, the range of Mashona cattle movement was 0 – 3 km from the water source. Seasonal activity patterns varied significantly across seasons. Therefore, Mashona cattle foraging behavior depends on seasonal variation. The landscape and animal attributes responded to paddock nutritional level dynamics with more frequent use of patches with higher plant species diversity and near the water source. Our research is useful to range managers, researchers, and cattle ranchers as a guideline for forage management of cattle preferred microhabitats, pasture, and nutrition.

Long‐Term Effects of Black‐Tailed Prairie Dogs on Livestock Grazing Distribution and Mass Gain

ABSTRACTThe conservation and management of black‐tailed prairie dogs (Cynomys ludovicianus) have been contentious issues in grasslands of central North America for much of the past century, primarily because of the perception that they compete with livestock for forage. Studies quantifying the magnitude of competition between prairie dogs and cattle are difficult to conduct because of the large spatial and long temporal scales needed to quantify how competition varies in response to interannual variation in precipitation and prairie dog abundance. We examined variation in mass gains of yearling steers in shortgrass steppe of northeastern Colorado, USA, with and without prairie dogs from 2008–2019, a period that encompassed a full cycle in prairie dog abundance from a nadir following plague‐induced population collapse, to peak abundance following population recovery, to plague‐induced population lows again. Analyses of cattle grazing distribution with global positioning system (GPS)‐collars revealed preferential grazing on colonies following a period of unusually high vegetation production, and preferential grazing off colonies following a period of rapid vegetation senescence, but these patterns were not clearly related to cattle mass gains. Across all 12 years of the study, average daily mass gain (ADG) during the growing season was 0.97 kg/steer/day in pastures where prairie dogs were controlled annually, and 0.95 kg/steer/day in pastures where they were not. Average daily mass gain was a quadradic function of precipitation and a linear function of prairie dog occupancy within a pasture, with a generalized linear mixed model predicting an 8.0% decrease in ADG as prairie dog occupancy increased from 0 to 60% of a pasture with average growing‐season precipitation. We did not detect a significant interaction between precipitation and prairie dog occupancy, but one limitation of our study is that the only drought year (2012) occurred when prairie dogs occupied low percentages (10–25%) of the study pastures. Prairie dogs had a small but detectable negative effect on cattle mass gains during the growing season in shortgrass steppe. The magnitude of this effect can be used by managers in combination with market conditions and the spatial extent of prairie dog colonies to estimate economic effects of prairie dogs on livestock operations. © 2021 The Wildlife Society. This article is a U.S. Government work and is in the public domain in the USA.

Opportunities to Apply Precision Livestock Management on Rangelands

Precision livestock management has become a new field of study as the result of recent advancements in real-time global positioning system (GPS) tracking, accelerometer and other sensor technologies. Real-time tracking and accelerometer monitoring has the potential to remotely detect livestock disease, animal well-being and grazing distribution issues and notify ranchers and graziers so that they can respond as soon as possible. On-going research has shown that accelerometers can remotely monitor livestock behavior and detect activity changes that are associated with disease and parturition. GPS tracking can also detect parturition by monitoring the distance between a ewe and the remainder of the flock. Tracking also has the potential to detect water system failures. Combinations of GPS tracking and accelerometer monitoring may be more accurate than either device used by itself. Real-time GPS tracking can identify when livestock congregate in environmental sensitive areas which may allow managers the chance to respond before resource degradation occurs. Identification of genetic markers associated with terrain use, decreased cost of GPS tracking and novel tracking data processing should facilitate development of tools needed for genetic selection for cattle grazing distribution. Precision livestock management has potential to improve welfare of livestock grazing rangelands and forested lands, reduce labor costs and improve ranch profitability and improve the condition and sustainability of riparian areas and other environmental sensitive areas on grazing lands around the world.

Cattle Grazing Distribution Patterns Related to Topography Across Diverse Rangeland Ecosystems of North America

Livestock distribution in extensive rangelands of North America can present management challenges to land managers. Understanding the role of topography on livestock distribution, within and across diverse rangeland ecosystems, could provide land managers valuable information for adaptive management of livestock to address both conservation and production goals from these ecosystems. Here, we examine the influence of topography on grazing distribution unevenness and intensity of use of beef cattle in seven rangeland ecosystems spanning arid, semiarid, and subtropical environments. We focused on grazing distribution during the late growing season (summer and autumn) periods when topographic variation in rangelands is more coupled to low and nonuniform availability of high-quality forage. Pasture size and water sources strongly influence grazing distribution across ecosystems. High unevenness of grazing occurred in pastures with extensive distances to water, low stock density, and more rugged topography. Conversely, more uniform grazing distribution occurred in smaller, well-watered pastures that support higher stock density (animals per unit area) and gentler terrain. Comparison of two topographic indices, topographic wetness index and topographic position class index, in terms of their ability to predict cattle grazing distribution, revealed that categorical topographic position classes were more effective. For most arid and semiarid rangelands, livestock grazing distributions showed affinities for lowlands and flat plains compared with open slopes and uplands. In contrast to drier rangelands, livestock grazing distributions exhibited preference for upland and sloped areas of subtropical pastures, as low-lying areas with water-inundation likely curtailed selection. Across these diverse rangeland ecosystems of North America, results provide benchmark information on livestock grazing distribution to formulate improvements in adaptive management and decision making and incorporate technological advancements in precision livestock management to integrate abiotic environmental information with spatial movements of livestock and temporal vegetation dynamics.

239 Grazing Distribution of Beef Cattle: Acronyms of Technology and Spatial Measures

Abstract Grazing distribution is an important aspect of pasture management, yet measuring traits for sustainable forage consumption is challenging. Uplands are often un-grazed by beef cattle due to rugged terrain while riparian zones are often heavily grazed; thus, sustainable consumption may be achieved if improved landscape utilization by cattle is encouraged. Modifying grazing behaviour with fencing and (or) water-source and feeding location(s) is effective in improving grazing patterns; however, these infrastructure improvements are typically expensive, supporting the concept of genetic selection for improved grazing distribution. Efforts funded by the Western Sustainable Research and Education Program (WSARE; SW15-015) using global positioning systems (GPS) indicated a genetic influence on quantitative traits describing grazing distribution of 330 Angus-influenced cows (i.e. distance from water, slope, elevation, vertical climb, etc.). Collars fitted with GPS devices for data collection accrued measures at intervals of 5 to 15 min and 10 m resolution for 3-19 weeks in 16 pastures on 14 ranches and experiment stations. Genome-wide association studies involving trait-measures and high-density genotypes (n = 777,962 single nucleotide polymorphisms; SNP) indicated these traits were polygenic. Combining SNP genotypes with trait measures and pedigree has become the norm in genetic evaluation and improvement processes (i.e. genome-enhanced expected progeny difference (GE-EPD). These processes require data from large numbers of animals (n &amp;gt; 10,000). Collecting grazing distribution phenotypes with GPS collars is accurate, but time-consuming; therefore, collaborative research is being conducted in the 2019-2020 academic year exploring the use of unmanned aerial vehicles (UAV) and cameras to ascertain spatial measures of beef cow grazing distribution. This collaboration involves scientists in the Colorado State University Drone Center, Department of Mechanical Engineering, and Department of Animal Sciences. The project objective is to determine if UAV can expedite data collection to support development of genetic evaluation and improvement programs for grazing distribution.

Timing and Duration of Observation Periods of Foraging Behavior in Natural Grasslands

The goals of this study were to evaluate the length of time grazing which should be monitored over a 24-h period to predict the grazing behavior of beef heifers within a season and determine the patterns of foraging activity over 24 h. A database was constructed between 2010 and 2012 for beef heifers managed under rotational grazing in a natural grassland. Grazing, rumination, and other activity times were assessed visually during 24 h on 15 occasions. Data were classified according to climatic seasons, generating 12 replicates in summer, 18 in spring, 24 in autumn, and 36 in winter. Treatments were the evaluation of four distinct periods: from sunrise to sunset (DAY-SUN), daylight duration from dawn to nightfall (DAYLIGHT), DAYLIGHT plus 2 h (DAYLIGHT+2), DAYLIGHT to midnight (DAYLIGHT to 0), and the entire 24 h period (CONTROL). Differences for grazing, rumination, and other activities were found in all seasons for the evaluation periods. Sampling sufficiency was reached only with the DAYLIGHT to 0 and CONTROL for all four climatic seasons. The DAYLIGHT to 0 treatment covered 75% of a 24-h period and 95% of the mean foraging time took place during this time interval. Considering grazing distribution during a day, in the warm seasons, the major grazing period during mornings occurred earlier than in the cool seasons, and in cool seasons, the grazing peak was observed during the afternoon. Visual observations from dawn until midnight represented the total grazing time and natural behavior of heifers and could be used to represent grazing activities for the entire day.

Cattle Grazing Distribution in Shortgrass Steppe: Influences of Topography and Saline Soils

The distribution of livestock across heterogeneous landscapes is often uneven, which has important implications for vegetation dynamics and how rangeland managers achieve desired outcomes from these landscapes. Here, we use data from widely available digital elevation models to classify a landscape in the shortgrass steppe with subtle topographic variation using two different approaches: topographic wetness index (TWI) and topographic position classes (TPCs) derived from topographic position indices. We used global positioning system collars to track the grazing locations of cattle within replicate pastures and fit generalized linear mixed models to their locations to quantify the influence of topography on grazing distribution. In addition, we examine the influence of the presence of saline vegetation communities on cattle use of lowlands. The resulting models indicate that TPC more effectively predicts grazing distribution than TWI and that the patterns are strongest in the second half of the growing season (August−October). Model performance was improved with the inclusion of saline vegetation communities, although the magnitude of cattle grazing time in these communities was not consistent across multiple pastures. These models, in combination with local knowledge, can be used by managers to predict and manage livestock distribution even in landscapes with relatively subtle topographic variability.

Optimising cattle grazing distribution on rangeland: a systematic review and network analysis

Optimising beef cattle (Bos taurus and Bos indicus) distribution, both spatially and temporally, is one of the most significant challenges associated with managing extensive grazed rangelands. Landscape variability and behavioural patterns of cattle may lead to non-uniform and inefficient forage utilisation, damage to critical habitats, and water quality impairment. In order to overcome these distribution challenges, a large suite of tools have been developed and researched to optimise grazing patterns. The objectives of this synthesis paper are 2-fold: (i) to survey and categorise distribution tools; and (ii) to analyse the connectivity of existing research across academic disciplines to identify and isolate knowledge gaps. A systematic literature review revealed specific types of tools and strategies to improve cattle distribution, which were categorised as either ‘animal’ or ‘environmental manipulations’. Animal manipulations utilise aspects of individual behaviour and herd dynamics to alter grazing patterns, whereas environmental manipulations involve transforming aspects of the animal’s surroundings to overcome challenges associated with inefficient distribution. This review reveals that strategies are overwhelmingly studied in isolation, and that there is potential to increase efficacy by integrating multiple strategies to achieve a desired outcome. Motivated by these findings, an author collaboration network analysis was conducted to investigate connectivity within and among author fields of expertise to understand why more integrated management strategies are not currently studied. Authors were classified into five fields of research: animal behaviour science, animal production science, biophysical rangeland science, economics, and other. The network analysis revealed that communities of authors contributing to papers on enhancing cattle distribution are disjointed. These results suggest that in order to fulfil knowledge gaps about the efficacy and cost of management strategies, there needs to be interdisciplinary engagement with particular attention to strategies that integrate animal and environmental manipulations to enhance cattle grazing distribution on extensively grazed landscapes.

283 Validation of Quantitative Trait Loci Associated with Grazing Distribution Traits in Beef Cattle Using Bayes C.

283 Validation of Quantitative Trait Loci Associated with Grazing Distribution Traits in Beef Cattle Using Bayes C.

Use of radio frequency identification (RFID) technology to record grazing beef cattle water point use

Current recommendations for the provision of water points for grazing beef cattle in northern Australia are based on effective grazing distribution rather than cattle water point use. Scientific examination of cattle watering behaviour under varying conditions of climate, pasture and water availability (i.e. distances between water points) is required to inform water infrastructure development recommendations and maximise cattle productivity. This study assessed the potential of Radio Frequency IDentification (RFID) reader data from remote weighing technology to examine cattle visit times and time intervals between cattle visits to water points. Data from three cattle stations in northern Australia was used. Daily weather data (temperature, humidity, wind speed, cloud cover, solar exposure and rainfall) were obtained from official weather stations located at or near each experiment site. Linear mixed-effects models were used to detect variation in cattle behaviour within and between stations. The RFID reader data showed that most cattle visits to water points occurred during daylight hours (between 06:00 and 19:00 h) and within 48 h of a previous visit. The time of day that cattle visited water points did not differ between stations (P > 0.05) but varied according to month (P = 0.001), period of day (P < 0.001), time since last visit (P = 0.013) and cloud cover (P = 0.043). Time intervals between cattle visits to water points differed considerably between stations (P < 0.002) and appeared to reflect seasonal conditions and water availability at each station. Time intervals between visits to water points also varied according to month (P < 0.001), period of day (P < 0.001), temperature-humidity index (P = 0.035) and cloud cover (P = 0.029). The results of the study show that RFID reader data is able to detect behavioural differences according to climate and water availability and is a suitable tool to study cattle water point use. Cattle water point use data could be used to aid mustering and trapping cattle, identify animals that fail to visit a water point, better understand pasture conditions, predict the amount and consistency of weight data collected from remote weighing technology, improve decision making by graziers and inform recommendations for the optimal number and distribution of water points.

Use of GPS tracking collars and accelerometers for rangeland livestock production research.

Over the last 20 yr, global positioning system (GPS) collars have greatly enhanced livestock grazing behavior research. Practices designed to improve livestock grazing distribution can now be accurately and cost effectively monitored with GPS tracking. For example, cattle use of feed supplement placed in areas far from water and on steep slopes can be measured with GPS tracking and corresponding impacts on distribution patterns estimated. Ongoing research has identified genetic markers that are associated with cattle spatial movement patterns. If the results can be validated, genetic selection for grazing distribution may become feasible. Tracking collars have become easier to develop and construct, making them significantly less expensive, which will likely increase their use in livestock grazing management research. Some research questions can be designed so that dependent variables are measured by spatial movements of livestock, and in such cases, GPS tracking is a practical tool for conducting studies on extensive and rugged rangeland pastures. Similarly, accelerometers are changing our ability to monitor livestock behavior. Today, accelerometers are sensitive and can record movements at fine temporal scales for periods of weeks to months. The combination of GPS tracking and accelerometers appears to be useful tools for identifying changes in livestock behavior that are associated with livestock diseases and other welfare concerns. Recent technological advancements may make real-time or near real-time tracking on rangelands feasible and cost-effective. This would allow development of applications that could remotely monitor livestock well-being on extensive rangeland and notify ranchers when animals require treatment or other management.

097 Grazing Behavior and Distribution Patterns of Kiko Wethers in Southern-Pine Silvopastures

097 Grazing Behavior and Distribution Patterns of Kiko Wethers in Southern-Pine Silvopastures

Elk Foraging Site Selection on Foothill and Mountain Rangeland in Spring

Previous research suggests facilitative grazing by cattle during the preceding summer-fall can enhance spring foraging habitat of Rocky Mountain elk (Cervus elaphus nelsoni). However, previous studies were limited to 1 year or conducted within relatively small experimental pastures. We evaluated elk foraging site selection during spring across 4 years and 59 040 ha of foothill and mountain rangeland in northwestern Wyoming and west-central Montana. Elk in spring avoided foraging in nonforested portions of cattle-grazed pastures where cattle had not grazed during the previous summer−early fall. In contrast, elk selected foraging sites where cattle had grazed lightly (11−30% forage use) or moderately (31−60% forage use), and selection by elk was stronger for moderately grazed sites. Neither moderate nor light cattle grazing intensity were correlated with any other elk habitat attribute that we sampled, and both moderate and light cattle grazing intensity exerted more influence on elk foraging site selection than any other variables, including distance to security cover, distance to primitive roads, distance to improved roads, aspect, or slope. We developed and validated a resource selection model that correctly classified 80−89% of elk foraging observations across five study sites and 4 years. Resource managers can use our model to map predicted changes in elk grazing distribution when considering potential habitat adjustments in security cover, roads, or cattle grazing intensities and distribution. Our results indicate that resource managers can use targeted cattle grazing in summer−early fall to purposely modify elk forage conditions to 1) increase elk foraging efficiency in spring, 2) lure elk away from places needing rest or deferment from spring elk grazing, or 3) lure elk away from places where elk in spring are experiencing conflicts with humans, predators, or other wildlife.

Pyric-herbivory and Hydrological Responses in Tallgrass Prairie

Pyric-herbivory is the spatial and temporal interaction of fire and grazing on area resources that results in site selection by animals on recently burned areas. Pyric-herbivory promotes heterogeneity by increasing bare ground on some patches and litter and aboveground biomass on other patches. The influences of this heterogeneity on hydrological properties and sediment transport are not well documented. We monitored the pattern of cattle occupancy on annually burned and patch burned pastures under moderate stocking rates of steers in the Tallgrass Prairie Preserve and quantified surface runoff and sediment transport for simulated rainfall of 10-year return storm intensity applied to different phases of the fire-grazing interaction in 2011 and 2012. Results showed that patch burn altered grazing distribution with cattle spending 70% of their time within the most recently burned areas. Our rainfall simulation results showed the high-intensity grazing following a spring fire did not have a prolonged, ecologically meaningful detrimental impact on hydrological properties of the burned patch in comparison with annually burned grazing pasture. Instead, the increased spatial and temporal heterogeneity of hydraulic properties could potentially enhance resource conservation through runoff and runon interactions within the patch-burned pasture. Further study focusing on quantifying pyric-herbivory effects on runoff and sediment transport at watershed scale will provide needed insights for managing tallgrass prairie for improving ecosystem services.

Genetic Influences on Cattle Grazing Distribution: Association of Genetic Markers with Terrain Use in Cattle

Eighty-seven cows were GPS (Global Positioning System) tracked for 1 to 3months in mountainous and/or extensive pastures at five ranches located in New Mexico, Arizona, and Montana. The Illumina Bovine HD SNP array, which evaluates approximately 770,000 genetic markers (i.e., single nucleotide polymorphisms; SNPs) across the 30 bovine chromosomes, was used to genotype DNA from these cows and to examine genetic associations with grazing distribution. Terrain use indexes were calculated from tracking data based on normalized averages of slope use, elevation use, and distance travelled from water. Genetic analyses identified a chromosomal region, known as a quantitative trait locus (QTL), associated with these traits. One genetic marker on chromosome 29 identified a gene that has been reported to be involved in locomotion, motivation, and spatial memory. This locus accounted for 24% of the phenotypic variation in use of steep slopes and high elevations, while another QTL on chromosome 17 accounted for 23% of the phenotypic variation. Three other QTLs accounted for 10% to 20% of the variation in terrain use indexes. Using results from the initial high-density genetic marker analyses, a smaller 50-SNP panel was developed targeting previously identified QTL regions and was used to evaluate the 85 cows tracked previously with an additional 73 cows from four ranches. With the 50-SNP panel analyses, multiple genetic markers near or within the gene identified on chromosome 29 confirmed the association with indexes of terrain use. In addition, genetic markers on chromosomes 4, 8, 12, and 17 accounted for a significant portion of the phenotypic variation in terrain use indexes. The associations between terrain use indexes and genetic markers near candidate genes demonstrate that grazing distribution can be inherited and provide a new approach to associate genetic variation with cattle grazing behavior of range beef cattle.