Grazing Events Research Articles

Automating dairy farm grazing records using GPS technology

Long-term grazing records can be used to assess paddock productivity (e.g., grazings per year), yet inconsistent record-keeping among New Zealand farmers hampers accurate analysis. Recently, GPS ear tags have emerged as an automated solution for identifying and recording paddocks grazed, providing data that could be used to underpin on-farm decisions and aid sector scale tracking of pasture productivity. Two GPS-enabled ear tags (GSatSolar and Ceres Trace) powered by solar energy and reporting direct-to-satellite were evaluated on two Waikato dairy farms for recording grazing events. Five cows were fitted with GSatSolar ear tags on each farm, and a further four were fitted with Ceres Trace ear tags on the second farm. Comparing the GPS location data with manual grazing records revealed varying levels of accuracy in identifying the grazed paddock. The grazing records inferred using the GSatSolar ear tags correctly matched the manual grazing records on 58% of occasions on the first farm and 85% on the second farm, with the difference being attributed to the number of working devices between farms. By comparison, the Ceres Trace ear tags identified the grazed paddock on 91% of occasions. These findings suggest that it is feasible to automate the recording of on-farm grazing events using GPS-enabled devices. However, a greater number of devices should be deployed, and/or the location reporting frequency must be increased to identify the grazed paddock accurately. The considerations when choosing devices for these purposes are also discussed, including reporting frequency and tag attachment methods.

Adaptive multi-paddock grazing increases mineral associated soil carbon in Northern grasslands

Grassland soils play an important role in sequestering carbon (C) and are primarily used for livestock grazing. Grazing management can increase the amount of C stored in soils and the distribution of C in different soil fractions by altering soil microbial community structure, thereby influencing the persistence of soil C over time. Adaptive multi-paddock grazing (AMP), grazing cattle at high stock densities with long periods between grazing events, is considered to enhance grassland sustainability, productivity, and soil C compared to more conventional grazing practices (continuous to slow rotational). However, whether and how AMP grazing might affect the amount of C stored in different soil fractions has received little attention. Soil samples (0–15 cm depth) were collected from 24 ranches in a paired design, where 12 ranches practiced AMP grazing and 12 neighboring ranches practiced conventional grazing. Soil organic C (SOC) and total nitrogen were measured in different soil particle size [fine (<53 µm), medium (53–250 µm) and coarse (>250 µm)], and density [light (>1.6 g cm−3), and heavy (<1.6 g cm−3)] fractions. Soil bacterial and fungal biomass and abundances were obtained from phospholipid fatty acid analysis. Mean weights of soil microaggregates and heavy fractions were higher in soil exposed to AMP grazing, whereas mean weights of macroaggregates and light fractions were higher in conventionally grazed soils. In warmer and drier climatic conditions, SOC in both bulk soils and within various size and density fractions tended to decrease. Soil organic C (both concentration and stock) were significantly higher in the fine soil fractions under AMP management than conventionally grazed grasslands. Given that SOC in fine fractions, is more mineral associated and recalcitrant, our results indicate that AMP grazing increased the size of the stable SOC pool. The increased carbon pool in the fine fraction was associated with greater fungal to bacterial ratios, suggesting a possible biological mechanism for the increase. Overall, the results indicate that AMP grazing may be beneficial for sequestering more stable carbon that helps mitigate the effects of climate change.

Behavioural responses of beef cattle to different grazing systems and the influence of these responses on water productivity of livestock in a tropical savannah

Environmental conditions and available forage on pastures greatly differ between different farming systems, which can affect the behaviour of grazing cattle. The interplay between environment-, forage-, and animal-related variables may affect the use of feed and water resources in grazing-based systems. Hence, our objectives were (i) to study the differences between grazing-based systems and seasons in environment- and pasture-related variables as well as the behaviour, feed intake, performance, and water productivity of Nellore heifers, and (ii) to understand the interrelationships between these variables. The measurements were performed in a conventional grazing system (CON), an integrated crop-livestock (ICL), and a crop-livestock-forestry (ICLF) systems in the Brazilian Cerrado during the rainy and dry seasons. Ambient temperature and relative air humidity were hourly measured in both seasons. Forage biomass and sward height were determined every month. Forage samples were taken to determine the proportions of alive leaves, alive stems, and dead plant material and to analyse their nutritive value. Forage intake, drinking water intake, and liveweight changes were quantified in 12 Nellore heifers per system and season. Feeding behaviour was recorded by chewing sensors on nine continuous days in each season. Drinking water intake was measured by water meters attached to drinking water troughs, whereby trial cameras at the troughs recorded the frequency of drinking events of individual animals. Feed conversion efficiency and water productivity were estimated. The ICLF reduced the exposure time to high ambient temperatures so that heifers even grazed during the hottest hours. Forage biomass in ICL and CON had greater proportions of stem and dead plant material than in ICLF. Forage intake rate was greater and grazing events were longer for animals in ICLF than those in CON, whereas the daily number of grazing events was greater in CON. Feed conversion efficiency and water productivity were greater in integrated systems than in CON. Amongst studied variables, thermal environment and forage canopy structure with its proportions of dead plant material are the main driving factors for animal behaviour, forage intake rate, and animal performance. These variables reduce feed conversion efficiency and water productivity in grazing cattle. Further research should analyse strategies for promoting thermal comfort for the animals, increasing the proportions of alive biomass, and enhancing the nutritional value of pastures for more efficient use of forage and water resources in grazing-based systems.

Milk production and nitrogen excretion of grazed dairy cows in response to plantain (Plantago lanceolata) content and lactation season.

The study aimed to quantify milk production and urinary nitrogen (UN) excretion of dairy cows grazing pastures containing varying contents of plantain (Plantago lanceolata) in different seasons, under a typical farm practice. Four pasture treatments: perennial ryegrass (Lolium perenne) - white clover (Trifolium repens) (RGWC), RGWC + low plantain rate, RGWC + medium plantain rate, and RGWC + high plantain rate, were established in four adaptation areas (1 ha each) and 20 experimental plots (800 m2 each), and rotationally grazed by dairy cows over 14 grazing events during two lactation years. In each grazing (8-9 days), 60 or 80 Jersey-Friesian lactation cows were assigned to their pasture treatments, adapted to their pastures over the first six days, then each group of 15 or 20 cows were randomly allocated for grazing in five treatment plots over a two or three-day measurement period. Milk, urine, and faecal samples were collected from individual cows during the measurement period. The pasture treatments did not affect milk production, the yield and composition of milk solids, protein, fat, and lactose. However, cows grazing pastures containing between 17-28% dietary plantain reduced UN concentration by 15-27%, decreased UN excretion by 4-9%, and increased urine volume by 22-40%, compared to grazing the RGWC pasture. The change in UN concentration, and urine volume were associated with plantain proportion in the diet and were greater during late summer and autumn than during early summer. Incorporating 17%-28% dietary plantain with RGWC pastures can reduce the risk of nitrogen losses from pastoral systems, while maintaining the milk production of dairy cows.

Increased pastoralist livestock mobility is associated with large-scale rangeland restoration and soil carbon sequestration.

Abstract Semi-arid rangelands cover 40% of the earth's land surface, but their ecosystem services have declined due to, among other factors, increasingly sedentary livestock husbandry by pastoralists. Such degradation might be reversed by adopting frequent, large-scale livestock movements similar to those associated with traditional nomadic pastoralist habits but data to support this hypothesis is lacking. We report here the consequences of implementing a program to increase the mobility of livestock grazing across 2 million ha in northern Kenya from 2014-2021, as compared to conditions prior to the program, 2001-2013. Despite increased human populations and livestock numbers on the study area during the program, nearly 60% of 213 sampled locations experienced the single major grazing events per year intended by the grazing program in at least 6 out of 7 years, with accompanying rainfall-corrected increases in forage biomass and soil carbon sequestration. Locations where mobile grazing was less consistently applied experienced neither of these responses. We demonstrate that increasing mobility in grazing practices within large-scale pastoralist systems can be implemented to improve range condition and soils and consequently sequester substantial CO 2 in soil organic carbon.

The repeatability and heritability of traits derived from accelerometer sensors associated with grazing and rumination time in an extensive sheep farming system

IntroductionThe automated collection of phenotypic measurements in livestock is of interest to both researchers and farmers. Real-time, low-cost, and accurate phenotyping can enhance precision livestock management and could lead to the optimized utilization of pasture and breeding of efficient animals. Wearable sensors provide the tools for researchers to develop novel phenotypes across all production systems, which is especially valuable for grazing conditions. The objectives of this study were to estimate the repeatability and heritability of traits related to grazing and rumination activities and their correlations with other traits.MethodsThis study was conducted on a commercial Merino farm in the west of Victoria, Australia, from 4 May 2020 to 29 May 2020. A total of 160 ActiGraph sensors embedded in halters were attached to the left side of the muzzles of Merino sheep (M = 74, F = 86) aged 10–11 months while the sheep were grazing on pasture. Support vector machine (SVM) algorithms classified the sensor output into the categories of grazing, rumination, walking, idle, and other activities. These activities were further classified into daily grazing time (GT), number of grazing events (NGE), grazing length (GL), rumination time (RT), number of rumination events (NRE), rumination length (RL), walking time (WT), and idle time (IT). The data were analyzed using univariate and bivariate models in ASReml-SA to estimate the repeatability, heritability, and phenotypic correlations among traits.ResultsThe heritability of GT was estimated to be 0.44 ± 0.23, whereas the other traits had heritability estimates close to zero. The estimated repeatability for all traits was moderate to high, with the highest estimate being for GT (0.70 ± 0.03) and the lowest for RT (0.44 ± 0.03). The intraclass correlation or repeatability at a 1-day interval (i.e., 2 consecutive days) was high for all traits, and steadily reduced when the interval between measurements was longer than 1 week.DiscussionThe estimated repeatability for the grazing traits showed that wearable sensors and SVM methods are reliable methods for recording sheep activities on pasture, and have a potential application in the ranking of animals for selective breeding.

Macrophyte species richness improves resilience to grazing

Abstract Grazing pressure is increasing in the northern Gulf of Mexico due to tropicalization (i.e. range expansion of tropical species) and conservation efforts. Populations of herbivorous parrotfish, green turtles and manatees are all increasing in this region, and overgrazing can lead to loss of foundation species and their associated ecosystem services. With environmental conditions changing rapidly and seagrass abundance declining in many regions globally, understanding mechanisms that promote seagrass resilience to stressors (e.g. grazing) will be crucial for managing and restoring seagrass meadows and the valuable ecosystem services they provide. Diverse communities often exhibit higher resilience due to positive interactions and increased response diversity (i.e. differing reactions to environmental change), indicating that diversity may provide a tool for enhancing seagrass resilience. To investigate how macrophyte species richness influences resilience to increased grazing pressure, we simulated green turtle grazing events every 2 weeks for 8 weeks in plots that naturally varied in species richness. We recorded macrophyte metrics between the simulated grazing events and after a longer 4‐week recovery period. Both species identity and species richness impacted response to simulated herbivory. Four weeks after the last simulated grazing event, plots with higher species richness had recovered macrophyte shoot density better than plots with lower species richness, indicating that species richness may increase resilience. The grazing events had the strongest negative impact on the persistent species (i.e. longer‐lived species with slower shoot turnover), Thalassia testudinum, reducing T. testudinum density and dominance and indicating that areas dominated by this species may be the most negatively impacted by increased grazing pressure. Synthesis: Our results showed a positive impact of species richness on resilience and indicated that persistent seagrass species may have reduced dominance following repeated disturbances. Diverse seagrass beds can, therefore, improve ecosystem stability by allowing opportunistic species to replace species that are most negatively impacted by disturbances. These findings can be used to incorporate resilience into ecosystem management and identify seagrass beds that may be less resilient to changing environmental conditions.

GPS technology as a tool to aid pasture management on dairy farms

This research determined the accuracy and precision of Global Positioning System (GPS) enabled devices as a potential tool to automate the recording of onfarm grazing events, which can be used to indicate productivity of paddocks (with number of grazings per year), or, when combined with other farm data, estimate nergy harvested. Static tests were initially conducted to determine the devices’ accuracy (location error) and precision (Circular Error Probability; CEP). Based on 11 Agtech and 22 mOOvement devices tested, the mean location error was 5.4 m and 34.2 m, respectively. The 95% CEP was 13.9 m and 77.6 m, respectively. In the subsequent on-farm study, 11 cows in a 400- cow milking herd were fitted with an Agtech and mOOvement ear tag and two with digitanimal collars. Data were analysed for the AM and PM grazing periods for four days. The digitanimal collars recorded 62.3% of total observations in the correct paddock, instead of adjacent paddocks or races, compared with 52.5% for the Agtech devices and 45.2% for the mOOvement ear tags. These results suggested that GPS technology isfeasible for the automated recording of grazing events. However, a longer-term study is required to demonstrate the value this technology could have for farmers.

The carbon balance of a temperate grazed pasture following periodic maize silage cropping depends on climate and management

Periodic cropping of otherwise permanent pastures can lead to large losses of carbon (C), especially if cropped for maize silage. The long-term effect on C stocks due to periodic cropping depends on whether the lost C is recovered before any future cropping events. Accordingly, this study tested the hypothesis that C lost during periodic cropping would be recovered following a return to permanent pasture within a rotationally grazed New Zealand dairy system. In New Zealand, maize silage is often used as supplemental feed, and its production can be part of the pasture renewal process whereby paddocks are cropped for a year or two before re-establishment of a permanent pasture. The net ecosystem carbon balance (NECB) was measured by combining eddy covariance measurements of the CO2 exchange (net ecosystem production; NEP) with measurements and estimates of all other flows of C for four years following the re-establishment of permanent pasture in a paddock previously cropped for maize silage. The NECB (negative values indicate C loss from the ecosystem) of the four years was –13, –21, –52 and −242 g C m-2 for an aggregated total of −328 g C m-2 indicating further C had been lost. November to January (late spring-summer) was identified as crucial for determining the annual NEP and NECB. NEP during November-January was dependent on climate and farm management. Monthly air temperature negatively correlated with NEP, while rainfall positively correlated with NEP for intervals equivalent to the time between grazing events. Increasing the interval between grazing events to around 28 days during November-January was beneficial for increasing NEP, but longer intervals had limited additional benefit. Small day-to-day management decisions such as the application of effluent, grazing rather than harvesting, and increasing the interval between grazing events have the potential to make small but additive gains to the NECB and provide opportunities to recapture lost C (or minimise further losses) following periodic maize silage cropping of permanent pastures. Data from four years, however, suggests little recovery of previously lost C and indicates that the current return period for periodic maize silage cropping (10–15 years per maize crop) might be too short to maintain C stocks.

Leveraging Campus Landscapes for Public Health: A Pilot Study to Understand the Psychological Effects of Urban Sheep Grazing on College Campuses.

Since the 1980s, college students in the U.S. have self-reported a decline in their physical and emotional health. With these conditions compounded by the COVID-19 pandemic and its physical distancing restrictions, higher education institutions have an increased responsibility to establish strategic interventions and health-promoting programs for their students. Research collaborations between public health professionals and environmental designers have highlighted the benefits of environmental factors, such as wildlife, street trees, and public parks, on mental health. This pilot project aims to build upon the transdisciplinary dialogue between ecology, design, and public health by examining the social benefits of grazing lawnscape management, which is the practice of using herbivorous livestock to manage turfgrass areas. Through the design of an accessible central campus grazing space for a flock of 25 sheep and use of online questionnaires, a smartphone-based single-item survey, and open-ended feedback given via social media, the UC Davis Sheepmower Project addresses three primary questions: (1) Are there differences in self-reported stress levels and well-being between people who did not watch grazing sheep (no sheepmower group) compared with those who did watch grazing sheep (sheepmower group)? (2) Does holding sheep grazing events create opportunities for education about well-being and engagement with the campus community? (3) Can this type of urban grazing installation ultimately contribute to the overall identity of a college campus? Web-based questionnaire results indicate there is no significant difference in self-reported stress levels between the two groups; however, the moment-in-time smartphone-based single item question suggests that the presence of sheep provides temporary, noticeable relief and enhanced mood for those who observe the animals. Reflections posted on social media suggested that participants found the sheep grazing events fostered feelings of community and placemaking within the campus identity. However, the questionnaire sample indicated the grazing events did not have a significant effect on participants' sense of place or overall campus identity. This transdisciplinary effort breaks down traditionally siloed approaches to human and environmental health and is an example of a whole-systems approach to developing innovative solutions and encouraging applied collective action.

Long‐duration remote underwater videos reveal that grazing by fishes is highly variable through time and dominated by non‐indigenous species

AbstractIn the marine environment, fish contribute to key ecological processes such as controlling food‐webs through top‐down impacts, especially on algae. To date, the assessment of fish grazing activity has mostly been performed using short‐term (&lt;1 h) censuses by divers or remote cameras which do not allow estimating the variability of grazing rate within and between days. However, understanding the temporal variation of fish activity and hence contribution of species to ecosystem functioning is of particular interest in the context of biological invasion. Here, using long‐duration remote underwater cameras, we recorded fish abundance and grazing events over three consecutive days in October 2019 in a shallow Mediterranean ecosystem from northern Crete. This novel approach allowed us to assess temporal variation of abundance and grazing activity of the two native (Sarpa salpa and Sparisoma cretense) and the two non‐indigenous fish species (Siganus rivulatus and Siganus luridus). Non‐indigenous Siganus rivulatus was the most common species in the studied coastal habitat, followed by the two native species while the non‐indigenous Siganus luridus was scarce. Overall, the non‐indigenous S. rivulatus and the native S. salpa are responsible for more than 90% of the recorded grazing activity with similar bite rates between the two species. More than 70% of the grazing activity arose in grazing pulses in the afternoon, supporting the diel feeding hypothesis according to which feeding is greater in the afternoon when nutritive quality of macrophytes is the highest. In addition, some of the highest peaks in grazing activity were driven by a few individuals. Hence, surveys of only abundance could not provide accurate estimates of herbivory. Last, Siganus rivulatus presence did not significantly affect grazing activity of the native Sarpa salpa. Our results demonstrate that long‐duration remote underwater videos are a useful tool to accurately assess the contribution of fishes to ecosystem functioning.

Adaptive multi-paddock grazing management's influence on soil food web community structure for: increasing pasture forage production, soil organic carbon, and reducing soil respiration rates in southeastern USA ranches.

BackgroundMeasurement of two grazing management’s influence on pasture productivity, soil food web structure, soil organic carbon and soil microbial respiration efficiency was conducted on five southeastern US, across-the-fence ranch pairs to compare adaptive multi-paddock grazing (AMP) management, using short grazing events with planned, adaptive recovery periods, to conventional grazing (CG) management, with continuous grazing at low stock density.MethodologyA point-in-time experimental field analysis was conducted to compare five AMP or CG ranch pairs to better understand the influence of grazing management on (a) standing crop biomass productivity; (b) soil food web community population, structure and functionality; (c) soil organic carbon accrual; and d) soil-C (CO2) respiration kinetics.ResultsAMP grazing systems outperformed CG systems by generating: (a) 92.68 g m−2 more standing crop biomass (SCB), promoting 46% higher pasture photosynthetic capacity (Two sample Mann-Whitney; Z = 6.1836; no DF in MW; p = 6.26 × 10−10; Effect size = 0.35) (b) a strong positive linear relationship of SCB with fungal biomass (R = 0.9915; F(1,3) = 175.35; p = 0.015); fungal to bacterial (F:B) biomass ratio (R = 0.9616; F(1,3) = 36.75; p = 0.009) and a soil food web proxy (R = 0.9616; F(1,3) = 36.75; p = 0.009) and a concurrent very strong inverse relationship with bacteria biomass (R = −0.946; F(1,3) = 25.56; p = 0.015); (c) significant predator/prey interactions with an inverse relationship with bacterial population biomass (R = − 0.946; F(1,3) = 25.56; p = 0.015) and a positive relationship with total protozoa enumeration (R = 0.9826; F(1,3) = 83.68; p = 0.003) when compared to SCB; (d) a 19.52% reduction in soil C (CO2) respiration rates (Two sample t-test; T = −2.3581; DF = 52.3541; p = 0.0221; Effect size = 0.59); and (e) a 20.6% increase in soil organic carbon (SOC) in the top 10 cm of soil profile (Two sample Mann–Whitney; Z = 2.6507; no DF in MW; p = 0.008; Effect size = 0.24). Rancher conversion to AMP grazing strategies would appear to regenerate soil food web population, structure, diversity and biological functionality helping to improve: carbon flow into plant biomass, buildup of soil carbon, predator/prey nutrient cycling and soil microbial respiration efficiency while offering improved climate resilience and a strategy to increase the capture and storage of atmospheric CO2 in soils of the world’s rangeland.

Nitrogen addition and defoliation alter belowground carbon allocation with consequences for plant nitrogen uptake and soil organic carbon decomposition

Grassland plants allocate photosynthetically fixed carbon (C) belowground to root biomass and rhizodeposition, but also to support arbuscular mycorrhizal fungi (AMF). These C allocation pathways could increase nutrient scavenging, but also mining of nutrients through enhanced organic matter decomposition. While important for grassland ecosystem functioning, methodological constraints have limited our ability to measure these processes under field conditions. We used 13CO2 and 15N pulse labelling methods to examine belowground C allocation to root biomass production, rhizodeposition and AMF colonisation during peak plant growth in a grassland field experiment after three years of N fertilisation (0 and 40 kg N ha−1 year−1) and defoliation frequency treatments (“low” and “high”, with 3–4 and 6–8 simulated grazing events per year, mimicking moderate and intense grazing, respectively). Moreover, we quantified the consequences for plant nitrogen (N) uptake and decomposition of soil organic C (SOC). Nitrogen fertilisation increased rhizodeposition and AMF colonisation (by 63 % and 54 %), but reduced root biomass (by 25 %). With high defoliation frequency, AMF colonisation increased (by 60 %), but both root biomass and rhizodeposition declined (by 35 % and 58 %). Plant N uptake was highest without N fertilisation and low defoliation frequency, and positively related to root biomass and the number of root tips. Therefore, when N supply is low and the capacity to produce C through photosynthesis is high, belowground C allocation to root production and associated root tips was important to scavenge for N in the soil. In contrast, the strong positive relationship between the rate of rhizodeposition and SOC decomposition, suggests that rhizodeposition may help plants to mine for nutrients locked in SOC. Taken together, the results of this study suggest that belowground C allocation pathways affected by N fertilisation and defoliation frequency affect plant N scavenging and mining with important consequences for long-term grassland C dynamics.

Grazing bifurcations and transitions between periodic states of the PP04 model for the glacial cycle

Abstract We look at the periodic behaviour of the Earth’s glacial cycles and the transitions between different periodic states when either external parameters (such as $\omega $) or internal parameters (such as $d$) are varied. We model this using the PP04 model of climate change. This is a forced discontinuous Filippov (non-smooth) dynamical system. When periodically forced this has coexisting periodic orbits. We find that the transitions in this system are mainly due to grazing events, leading to grazing bifurcations. An analysis of the grazing bifurcations is given and the impact of these on the domains of attraction and regions of existence of the periodic orbits is determined under various changes in the parameters of the system. Grazing transitions arise for general variations in the parameters (both internal and external) of the PP04 model. We find that the grazing transitions between the period orbits resemble those of the Mid-Pleistocene-Transition.

Crabgrass as an equine pasture forage: impact of establishment method on yield, nutrient composition, and horse preference

Warm-season grasses (WSG) incorporated into traditional cool-season rotational grazing systems to increase summer yields are typically established in monoculture in separate pasture areas. Few studies have evaluated alternative interseeded establishment of WSG, despite potential benefits for improving biodiversity and land-use efficiency. The objective of this study was to determine the impact of establishment method (monoculture vs. interseeded) on crabgrass pasture forage yield, nutritive value, and preference under equine grazing. Three adult standardbred mares grazed two main plots on two consecutive days (8 hr/d) for three grazing events in 2019: Jul 28/29 (GRAZE 1), Aug 20/30 (GRAZE 2), Oct 1/2 (GRAZE 3). Each main plot contained four replicates of three treatments: mixed cool-season grass (CSG); Quick-N-Big crabgrass (CRB) [Digitaria sanguinalis (L.) Scop.] interseeded into existing cool-season grass (INT), and CRB established as a monoculture (MON). The cool-season grass mix included Inavale orchardgrass [Dactylis glomerata (L.)], Tower tall fescue [Lolium arundinaceum (Schreb.) Darbysh.], and Argyle Kentucky bluegrass [Poa pratensis (L.)]. Herbage mass (HM) and sward height (SH) were measured prior to each grazing event and samples were collected (0800–1000 h) for chemical composition analysis. Observed grazing time (GT) in each sub-plot as determined by 5-min scan sampling was utilized as marker of horse preference. Forage HM was greater in MON (8043 ± 1220 kg/ha) than CSG (5001 ± 1308 kg/ha; P = 0.003), with a trend for greater total HM in MON vs. INT (6582 ± 1220 kg/ha: P = 0.06), but HM did not differ between INT and CSG. The SH was also greatest for MON (28 ± 1.11; INT: 23.6 ± 1.11; CSG: 19.7 ± 1.37 cm; P < 0.003). Forage nutrients (digestible energy and crude protein) were largely similar across treatments and met requirements of horses at maintenance. Horse GT was lower in MON (22.6 ± 3.77 min/sub-plot) than in INT (31.9 ± 3.79 min/sub-plot; P = 0.003) and there was a trend for lower GT in MON vs. CSG (29.9 ± 4.17 min/sub-plot: P = 0.07). These results indicate interseeding CRB would not effectively increase yields of traditional cool-season grass equine rotational grazing systems and would not supply similar levels of summer forage provided by monoculture establishment. Results of this study also suggest horses may prefer cool-season grass pasture forage over warm-season crabgrass.

Vegetation, water infiltration, and soil carbon response to Adaptive Multi-Paddock and Conventional grazing in Southeastern USA ranches

We examine Adaptive Multi-Paddock (AMP) grazed with short grazing events and planned recovery periods and paired ranches using Conventional Continuous Grazing (CG) at low stock density on vegetation, water infiltration, and soil carbon across SE USA. Increased vegetation standing biomass and plant species dominance-diversity were measured in AMP grazed ranches. Invasive perennial plant species richness and abundance increased with AMP grazing in the south, while in the north they increased on CG grazed ranches. Percent bare ground was significantly greater in CG at the Alabama and Mississippi sites, no different at the Kentucky and mid-Alabama sites, and greater on AMP at the Tennessee pair. On average, surface water infiltration was higher on AMP than paired CG ranches. Averaged over all locations, soil organic carbon stocks to a depth of 1 m were over 13% greater on AMP than CG ranches, and standing crop biomass was >300% higher on AMP ranches. AMP grazing supported substantially higher livestock stocking levels while providing significant improvements in vegetation, soil carbon, and water infiltration functions. AMP grazing also significantly increased available forage nutrition for key constituents, and increased soil carbon to provide significant resource and economic benefits for improving ecological health, resilience, and durability of the family ranch.

Population dynamics of an island population of water voles Arvicola amphibius (Linnaeus, 1758) with one major predator, the eagle owl Bubo bubo (Linnaeus, 1758), in northern Norway

Predator–prey relationships are of great significance to ecosystems, and their effects on the population dynamics of voles and lemmings (Microtinae) in Boreal and Arctic environments have long been of particular interest. A simple ecosystem with one major prey and one major predator could be an ideal setting for a study of their interactions. This is the situation on several small islands on the coast of northern Norway just below the Arctic Circle, with populations of water voles Arvicola amphibius preyed upon by the eagle owl Bubo bubo. The population dynamics of the water vole was studied by trapping and tagging in 2003–2018, eagle owl pellets were collected for analyses, eagle owl breeding attempts were recorded, and some weather variables collected from official recordings. After having been introduced well into the study period, the number of sheep Ovis aries was also recorded. Water voles were the main prey of the eagle owl, with 89% occurrence in pellets, with an overrepresentation of adults and males. Both predation, sheep grazing and extreme weather events influenced the vole population. Predator exclusion, as happened in three summers due to an intensive radio tracking study, especially increased the number of surviving young (in particular from the early cohorts) and the mass of adults. Extreme weather events, such as flooding in summer and deeply frozen ground in winter, most significantly reduced vole populations. Sheep grazing may exacerbate the effects of predation. A similar multitude of factors may affect populations of other rodent species as well.

Nitrous oxide emission factors from an intensively grazed temperate grassland: A comparison of cumulative emissions determined by eddy covariance and static chamber methods

Quantifying nitrous oxide (N2O) emissions from grazed pastures can be problematic due to the presence of hotspots and hot moments of N2O from animal excreta and synthetic fertilisers. In this study, we quantified field scale N2O emissions from a temperate grassland under a rotational grazing management using eddy covariance (EC) and static chamber techniques. Measurements of N2O by static chambers were made for four out of nine grazing events for a control, calcium ammonium nitrate (CAN), synthetic urine (SU) + CAN and dung + CAN treatments. Static chamber N2O flux measurements were upscaled to the field scale (FCH FIELD) using site specific emission factors (EF) for CAN, SU+CAN and dung + CAN. Mean N2O EFs were greatest from the CAN treatment while dung + CAN and SU + CAN emitted similar N2O-N emissions. Cumulative N2O-N emissions over the study period measured by FCH FIELD measurements were lower than gap-filled EC measurements. Emission factors of N2O from grazing calculated by FCH FIELD and gap-filled were 0.72% and 0.96%, respectively. N2O-N emissions were derived mainly from animal excreta (dung and urine) contributing 50% while N2O-N losses from CAN and background accounted for 36% and 14%, respectively. The study highlights the advantage of using both the EC and static chamber techniques in tandem to better quantify both total N2O-N losses from grazed pastures while also constraining the contribution of individual N sources. The EC technique was most accurate in quantifying N2O emissions, showing a range of uncertainty that was seven times lower relative to that attributed to static chamber measurements, due to the small chamber sample size per treatment and highly variable N2O flux measurements over space and time.

Grazing diverse combinations of tanniferous and nontanniferous legumes: implications for foraging behavior, performance, and hair cortisol in beef cattle.

A diversity of forages with different types and concentrations of nutrients and plant secondary compounds may lead to complementary relationships that enhance cattle performance and welfare. We determined whether grazing combinations of tanniferous legumes (Lotus corniculatus, birdsfoot trefoil [BFT], Onobrychis viciifolia, sainfoin [SF]), and alfalfa [ALF] (Medicago sativa) influence foraging behavior, performance, and hair cortisol concentration in beef cattle compared with grazing the same legumes as monocultures. Twenty-one pairs of heifers grazed three spatial replications of seven treatments: monocultures of BFT, SF, or ALF, and all possible two- and three-way choices among strips of these legumes: SF-BFT, ALF-BFT, ALF-SF, and ALF-SF-BFT in two periods of 25 d each (adaptation phase + experimental period) during two consecutive years. The lowest incidence of grazing events occurred in the BFT treatment (42.0% of the total scans recorded; P < 0.10), with the rest of the treatments ranging between 47.8% (SF-BFT) and 52.6% (ALF-SF) of the total scans recorded. Heifers selected a varied diet, preferring SF over BFT or ALF in a 46:27:27 ratio for the three-way choice, and in a 70:30 ratio for both two-way choices. Heifers preferred BFT over ALF (62:38 ratio) in a two-way choice. All treatments followed similar daily grazing patterns (P > 0.10), with two major grazing events (1 h after sunrise and 3 h before dark). No differences among treatments were observed for the number of steps taken by heifers on a daily basis, motion index, or the percentage of time heifers spent standing (1,599, 5,356, and 45.3%, respectively; P > 0.10), suggesting that heifers on choice treatments did not invest extra time in walking, searching, or patch switching activities relative to heifers grazing monocultures. Heifers grazing the three-way choice gained more body weight (1.27 kg/d) than the average gains observed for animals grazing in all legume monocultures (1.00 kg/d; P = 0.014) or two-way choices (0.97 kg/d; P = 0.007), suggesting a synergism among pasture species for the treatment with the highest diversity. No differences in hair cortisol concentration were observed among treatments, with values ranging between 1.4 (BFT) and 2.12 ng/g (three-way choice; P > 0.10). Thus, forage diversity has the potential to enhance animal performance without affecting grazing efficiency, likely explained by the spatial arrangement of the forage species presented in the study.

Bi-stability induced by motion limiting constraints on boring bar tuned mass dampers

This paper investigates the effect of displacement constraints on the attenuation performance of tuned mass dampers (TMDs) used in boring and turning applications. A simplified piecewise-smooth mechanical model is investigated through time domain simulations and hybrid periodic orbit continuation, first under harmonic excitation, then under regenerative cutting load. A quasi-frequency response function is derived for impacting TMDs through composition of different families of period-1 orbits, then an acceptability map for turning is formulated based on the appearance of cutting-edge contact-loss and fly-over events. The bi-stable domain boundaries are determined through two parameter continuation of contact-loss grazing events. It is shown that in both cases arising rigid body collisions can significantly hinder TMD damping performance and lead to resonance problems or machine tool chatter.