Removal Of Cattle Research Articles

Cover crop grazing length impacts on soil health and crop productivity in US Coastal Plain soils

AbstractIntroducing integrated crop‐livestock systems into row crop production promotes income diversification and potential soil health benefits through cover crop grazing on degraded soils of the southeastern United States, but effects of these practices on crop yields and soil health in Coastal Plain soils are not well established. A 4‐year study was performed to evaluate the effects of grazing a multi‐species winter cover crop on soil health and crop yields under mid‐February, mid‐March, and mid‐April cattle removal dates and a non‐grazed control within an annual cotton (Gossypium hirsutum L.) and peanut crop rotation (Arachis hypogaea L.). Chemical soil health indicators (soil organic carbon and permanganate oxidizable carbon), physical soil health indicators (water‐stable aggregates and penetration resistance), biological soil health indicators (microbial biomass carbon, soil respiration, and arbuscular mycorrhizal fungi colonization), crop yield, and cover crop biomass were evaluated. Cover crop biomass at termination was reduced by 3660, 5250, and 5610 kg ha−1 for the mid‐February, mid‐March, and mid‐April cattle removal treatments compared to the non‐grazed control. No grazing treatment effects were observed for biological soil properties. Soil organic carbon was higher in the non‐grazed treatment than the mid‐April grazing treatment across 0‐ to 30‐cm depth. Penetration resistance across 0‐ to 50‐cm depth and water‐stable aggregates at the 0‐ to 30‐cm depth were both negatively impacted by increased grazing period lengths. Results from this study suggest that longer cover crop grazing periods have little effect on biological and chemical soil health indicators in the short term but can negatively impact some physical soil health indicators.

Bovine leukemia virus transmission rates in persistent lymphocytotic infected dairy cows.

Bovine leukemia virus (BLV) establishes a lifelong persistent infection in dairy cattle. White blood cell count (WBC) is correlated with proviral load in the blood and milk of BLV-infected cattle, and testing WBC can be used to assess both BLV infectiousness levels and risk of BLV transmission from different types of infected animals. The objective of the study was to compare effective transmission rates (β) and the basic reproduction ratio (R o) among two types of BLV-infected dairy cows in Chile: those affected with persistent lymphocytosis (PL) vs. aleukemic (AL).The estimated (β) coefficient was higher in PL cattle [1.1; 95% Confidence interval (CI) (-1.6, 3.8)], compared to AL cattle (-3.1; 95% CI = -3.7, -2.5). In addition, the R o was higher in PL cattle (60.4; 95% CI = 3.5; 820.6), compared to AL cattle (1.5; 95% CI = 0.7, 3.1). The ratio between PL/AL expected rate of cases was 73.9. The estimated effective transmission rate and the Ro were higher in PL cattle compared to AL cattle. The WBC test is a convenient alternative that can be considered for risk identification and risk management of BLV infection in dairy herds; particularly in livestock regions where laboratory capacity is limited (e.g., use of PCR or gene sequencing techniques) and/or molecular tests are not cost-effective. Therefore, when prevalence of infection is high, the removal of PL cattle should be engaged to control BLV within-herds.

The need for an evidence-led approach to rewilding

This paper characterises current rewilding activities in the UK, through the analysis of 66 rewilding projects. Project information was obtained from online data (65 %), and direct mail data requests (35 %). The analyses showed an exponential growth in the number of new rewilding projects since 2010, with 8 % of projects started prior to 2000, and 60 % initiated after 2010. Seventy-three percent of projects involved rewilding areas of less than 1000 ha, 17 % being between 1000 and 10,000 ha, and 9 % greater than 10,000 ha. In Scotland, 80 % of the area being rewilded involved mountain, heath and bog habitats. For England the largest rewilded areas (58 %) were semi-natural or improved grasslands. Fifty-six percent of sites were formerly used for livestock farming, and 24 % for arable cultivation. A total of 72 % of sites employed tree planting, 64 % introduced herbivores, and 33 % introduced non-herbivores. The removal of sheep and cattle took place in 51 % of projects, with deer control in 33 %, wetland creation in 39 %, and the removal of artificial drainage in 36 % of projects. There was a close geographical proximity between rewilding sites and Sites of Special Scientific Interest (SSSI), with 69 % of areas being within 4 km, and only two sites greater than 8 km. Twelve project funding sources were recorded, and most projects utilised multiple funding sources. The benefits of an evidence-led and nationally co-ordinated rewilding approach were identified in relation to using well-established decision tools and frameworks to enhance future rewilding spatial planning. This would allow the development of a map of ‘appropriate’ rewilding areas, based on landscape scale characteristics, national species and habitat priorities, and predicted future landscape changes. Importantly, these ‘target’ areas would also be sensitive to local social, economic and agricultural contexts.

Multi-attribute, graph-based approach for duplicate cattle removal and counting in large pasture areas from multiple aerial images

In this study, we address the challenges of counting cattle in large pasture areas using Unmanned Aerial Vehicles (UAVs) equipped with high-resolution cameras. Traditional manual counting methods are laborious and error-prone, while existing automated approaches struggle with duplicate animal detection. To overcome these limitations, we propose a novel graph-based method that incorporates multiple-attributes, including velocity, direction, state (lying down or standing), color, and distance, to improve duplicate removal and counting accuracy. We conducted extensive experiments involving automated hyper-parameter learning to effectively integrate these attributes into our method. By employing a Ford–Fulkerson graph algorithm, we detect and remove duplicated cattle based on their multiple attributes. An ablation study validates the contribution of each attribute. Additionally, we provide new datasets of drone images captured in large pastures to support research in this field. Our results demonstrate that our proposed method outperforms state-of-the-art techniques, achieving an average percentage error of 2.34%. Comparisons with mosaic-based and other graph-based methods validate the effectiveness of our approach, which contributes to more efficient cattle counting practices and enhances livestock management in agriculture.

Investigation of the association between the Enferplex bovine tuberculosis antibody test and the future risk of bovine tuberculosis in irish cattle in infected herds: a pilot field study

The Single Intradermal Comparative Tuberculin Test (SICTT) and the interferon-gamma (IFN-γ) assay are the approved diagnostic tests for bovine tuberculosis (bTB) in Ireland. The aim of this pilot study was to explore if there was any added diagnostic benefit from applying the Enferplex bTB test (an antibody test) in severe bTB herd breakdowns after the removal of cattle that had tested positive to the SICTT and the IFN-γ test. In addition to the normal bTB testing and management protocols, the animals in these herds that tested negative to SICTT and the IFN-γ test were followed forward for a period of two years. All animals were tested by Enferplex at enrolment. The time to subsequent bTB detection (diagnosed with SICTT/IFN-γ tests or detection of visible lesions at routine slaughter) for animals that tested positive or negative to the Enferplex bTB test at the start of the study was compared using Kaplan–Meier survival curves and Cox based survival models. Of the 484 enrolled animals (from 11 herds), 171 (35.3%) and 151 (31.1%) initially tested positive in the Enferplex assay under the high sensitivity and high specificity interpretation settings respectively. The results of the survival analysis showed that there was no difference in the survival time to a positive diagnosis with bTB during the follow-up period between animals initially classified as positive and negative by the Enferplex test. Further research is warranted to explore the potential benefit of using the Enferplex test in other scenarios.

117 Effects of Cattle Removal Date on Sustainability of Cool-Season Annual Grazed Cover Crop Systems

Abstract Grazing of cool-season cover crops has been shown to be a viable tool in extending the grazing season while mitigating environmental risks associated with row crop farming systems. While there is a vast amount of research available on cover crops in relation to soil health, a more novel approach would be to focus on forage production and animal performance when grazing cover crops. Therefore, our objective was to evaluate the effects of cattle removal date on forage yield, forage quality, and steer performance when grazing cool-season cover crops. A cool-season forage mix consisting of ‘Cosaque’ oats (Avena strigose), ‘FL401’ cereal rye (Secale cereal), ‘AU Sunrise’ crimson clover (Trifolium incarnatum), and ‘T-raptor’ brassica (Brassica napus × B. rapa) was established in twelve, 0.62 ha paddocks in Headland, AL. Each paddock was then randomly allocated to one of four cattle removal treatments: 1) no grazing (CON); 2) February removal (FEB); 3) March removal (MAR); or 4) April removal (APR). Three tester steers were randomly allotted, based on body weight (BW), to each of the grazing treatments, excluding CON. The tester steers were weighed every 30 d for calculation of initial BW, final BW, and average daily gain (ADG). At inception and every subsequent two weeks, forage was harvested to analyze average forage yield, neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude protein (CP). All data were analyzed using GLIMMIX procedure of SAS version 9.4 (SAS Inst., Cary, NC). Significant differences in forage yield were detected between CON and FEB (3,913 vs. 2,261 kg/ha; P < 0.001), CON and MAR (3,913 vs. 1,790 kg/ha; P < 0.001), and CON and APR (3,913 vs. 1,810 kg/ha; P < 0.001). There were no differences found for ADG (1.2 kg/day; P = 0.56), NDF (50.94%; P = 0.46), or ADF (30.34%; P = 0.25) among treatments. Results indicate that grazing of cool-season annual cover crops will reduce forage yield, but removal date of cattle will not further affect forage yield, quality, or individual cattle performance. Thus, we can reduce winter supplementation needs for cattle by increasing grazing days; however, under continuous grazing for stocker cattle production, forage availability may inevitably be the limiting factor.

Comparing microRNA in milk small extracellular vesicles among healthy cattle and cattle at high risk for bovine leukemia virus transmission

Enzootic bovine leukosis (EBL) is a B-cell lymphosarcoma caused by bovine leukemia virus (BLV) infection. In Japan, cattle diagnosed with EBL are not permitted for human consumption by the law, thereby causing serious economic losses to farmers. The prevalence of BLV is high in Japan (40.9% in dairy cattle and 28.7% in beef cattle, respectively), which makes it difficult to perform the test-and-slaughter of BLV-infected cattle. This necessitates preventing the spread of BLV infection in cattle by early detection, segregation, and the removal of BLV-infected cattle with high proviral load, which are considered high risk for BLV transmission. We aimed to identify cattle that were at high risk for BLV transmission by comparing microRNA (miRNA) profiles in milk small extracellular vesicles (sEV). At first, miRNA profiles in sEV were compared among 4 uninfected cattle and 4 BLV-infected cattle with high proviral load by using a microarray containing mixed probes for miRNA of cattle and humans. Significantly lower amounts of hsa-miR-557 and hsa-miR-19b-1-5p, and insignificantly but higher amounts of hsa-miR-424-5p were observed in milk sEV from BLV-infected cattle than those from uninfected cattle. Next, to evaluate the utility of the aforementioned miRNAs for the identification of cattle that were at high risk for BLV transmission, we performed quantitative real-time PCR using milk sEV newly collected from 5 uninfected cattle and 17 BLV-infected cattle with high proviral load. The cycle threshold value of hsa-miR-424-5p was significantly lower in milk sEV from BLV-infected cattle. The PCR detection was unavailable or a significant difference was not observed for hsa-miR-557 and hsa-miR-19b-1-5p, respectively. These results suggest that the amount of hsa-miR-424-5p was higher in milk sEV from BLV-infected cattle and increasing the hsa-miR-424-5p in milk sEV could be one of the characteristic trends in cattle that are high risk for BLV transmission. Moreover, assessing characteristic miRNA amounts in milk sEV, which can be recovered twice a day by milking, could be useful for the routine monitoring of cattle in dairy herds instead of blood collection.

Consequences of an ecosystem state shift for nitrogen cycling in a desert stream

AbstractCessation of cattle grazing has resulted in the reestablishment of wetlands in some streams of the U.S. Southwest. Decades of cattle grazing prevented vascular plant growth in Sycamore Creek (Arizona, U.S.A.), resulting in stream reaches dominated by diatoms and filamentous green algae. Establishment of vascular plants can profoundly modify ecosystem processes; yet, the effects on nitrogen (N) cycling remain unexplored. We examined the consequences of this ecosystem state shift on N cycling in this N‐limited desert stream. We compared results from whole‐reach ammonium‐N stable isotope (15NH4+) tracer additions conducted before (pre‐wetland state) and 13 yr after (wetland state) free‐range cattle removal from the watershed. Water column estimations showed that in‐stream N uptake and storage were higher in the pre‐wetland than in the wetland state. N turnover was also higher in the pre‐wetland state, indicating that assimilated N was retained for shorter time in stream biomass. In addition, N uptake was mostly driven by assimilatory uptake regardless of the ecosystem state considered. Water column trends were mechanistically explained by the fact that the dominant primary uptake compartments in the pre‐wetland state (i.e., algae and diatoms) had higher assimilatory uptake and turnover rates than those in the wetland state (i.e., vascular plants). Overall, results show that the shift in the composition and dominance of primary producers induced by the cessation of cattle grazing within the stream‐riparian corridor changes in‐stream N processing from a dominance of intense and fast N recycling to a prevalence of N retention in biomass of primary producers.

102 Effects of Cattle Removal Date on Forage Production and Steer Performance in Grazed Cover Crops

Abstract Grazing of cool-season cover crops has been shown to be a viable tool in extending the grazing season while mitigating environmental risks associated with row crop farming systems. Grazing cover crops is not novel, but most information available on this practice focuses on soil health as opposed to forage production and animal performance. The objective was to evaluate the effects of cattle removal date on steer performance, forage yield, and forage quality. Twelve 1.2-ha pastures were established in a forage mix consisting of ‘Cosaque’ oats (Avena strigose), ‘FL401’ cereal rye (Secale cereale), ‘AU Sunrise’ crimson clover (Trifolium incarnatum), and ‘T-raptor’ brassica (Brassica napus ×B. rapa) and randomly allocated to be grazed through either mid-February (FEB), mid-March (MAR), or mid-April (APR) with an un-grazed control (CON). Three tester steers were randomly placed in each paddock with the exception of CON and allowed ad libitum grazing. Animals were weighed every 30 d for determination of average daily gain (ADG). Forage was harvested bi-weekly and analyzed for average yield, NDF, ADF, and CP. All data were analyzed using MIXED procedure of SAS version 9.4 (SAS Inst., Cary, NC). The following data represents the first three years of a four-year project. Differences in yield were detected between CON and FEB (3,913 vs. 2,398 kg/ha; P < 0.001), CON and MAR (3,913 vs. 1,908 kg/ha; P < 0.001), and CON and APR (3,913 vs. 2,126 kg/ha; P < 0.001). A difference in CP was detected between MAR and CON (13.36% vs. 11.78%; P < 0.02). No differences were detected for ADG (1.2 kg/day, P = 0.56), NDF (52.48%, P = 0.99), or ADF (30.82%, P = 0.4) among treatments. These results indicate that grazing will reduce forage yield, but removal date of cattle will not further affect forage yield or steer average daily gain.

Northern Bobwhite Response to Vegetation Management and Recovery in South Texas

The northern bobwhite (Colinus virginianus; hereafter, bobwhite) requires habitat structure and composition with grass cover for nesting, predator avoidance, and thermal refuge and forb cover for feeding on phytophagous arthropods and seeds. During the past 2 decades, many land managers with interest in promoting quail hunting opportunities have reduced or completely eliminated livestock across South Texas, USA, rangelands. Resting the land from grazing allows vegetation—especially grasses and forbs—to recover and thus provide nesting and foraging habitat for bobwhite and other birds. How bobwhite respond to postgrazing vegetation recovery is of keen interest to rangeland quail managers, but this topic is poorly known because case histories with quantitative data are lacking. Our objective was to investigate how bobwhite respond to the vegetation changes following removal of cattle grazing. Our study was conducted on a private ranch in Jim Hogg County, Texas and involved 3 different categories of postgrazing recovery and management: 1 area at 15 years post-cattle grazing where the landscape has been brush-sculpted and is actively managed since removal of cattle, 1 area at 3 years post-grazing with a previous stocking density of 7 ha/animal unit (high stocking density), and 1 area at 3 years post-grazing with a previous stocking density of 14 ha/animal unit (moderate stocking density). We trapped, radio-marked, and located bobwhites from March to September during 2015–2016 on the 3 comparative units. We estimated nest survival, adult breeding-season survival, home range size, and early winter density. We hypothesized that the 15-year postgrazing site would have higher early winter density, higher adult breeding season survival, and higher nest survival along with smaller mean home range size compared to the 2 more recently grazed sites. On average, the probability of a nest surviving the 23-day incubation period was highest on the 15-year postgrazing site at 0.61 ± 0.12 (mean nest survival ± standard error), with estimates of 0.32 ± 0.12 on the 3-year moderate postgrazing site and 0.33 ± 0.12 on the 3-year high postgrazing site. Adult breeding season survival did not differ among the 3 sites, and was instead influenced mostly by month within the season, probably a result of summer heat. An adult bobwhite had a 0.48 ± 0.04 probability of surviving the breeding season. Early winter density, after summer and fall production was complete, increased on all sites from 2015 to 2016 and was consistently highest on the 15-year postgrazing site. Home range sizes on the

Weak negative responses of spider diversity to short-term ‘kraaling’

The influence of short-duration, concentrated kraaling (enclosure) has been documented for plants, wildlife, and macro-invertebrates. However, limited information is available on its impact on ground-dwelling spiders. The purpose of this study was to assess the effect of short-duration kraaling, time since cattle removal, and microhabitat variables on spider assemblages in Matabeleland North Province, Zimbabwe. We used a matched-pair and space for time design (inside vs outside previously kraaled inclusions) across 11 sites, using four cattle herds (H1, H6, H7 and HNguni). Spiders were sampled in the early and late rainy season with pitfall traps left open for 14-day sampling periods and emptied twice in each period. We captured 634 spiders, comprising 63 species in 44 genera and 18 families. The most abundant family was Lycosidae (37%; 16 spp.), followed by Gnaphosidae (15%; 10 spp.) and Salticidae (14.5%; 7 spp.). Generalised linear mixed models showed that generic richness was greater in sites with more bare ground. However, this effect was reversed in previously kraaled sites, and was particularly evident for spider abundance that responded negatively relative to unkraaled sites. Furthermore, with a U-shaped recovery, generic richness increased with time since kraaling. Model-based multivariate models showed that short-duration kraaling had a significant impact on spider assemblage structure, but this impact was relatively small compared with the effect of seasonality. Most of the species that made significant contributions to this multivariate response were less abundant in kraaled sites. Spider diversity, therefore, had a weak negative response to short-term kraaling. However, these impacts should also be assessed at broader scales, including areas where cattle go to graze during the day.

Impacts of winter grazing on soil health in southeastern cropping systems

AbstractCoastal Plain soils are often characterized by low soil organic carbon (SOC) as a result of natural and anthropogenic factors. A rotation of cotton (Gossypium hirsutum L.) and peanut (Arachis hypogaea L.) under conventional tillage is typical in this region, but an opportunity to increase SOC and improve soil health by incorporating winter grazing of cover crops exists for producers with row crop and livestock operations. A study to assess winter grazing impacts on soil health was established in the U.S. Coastal Plain. Three cattle removal dates and an ungrazed control were evaluated for impacts on selected soil health indicators: SOC, permanganate oxidizable carbon (POXC), water stable aggregates (WSA), penetration resistance (PR), microbial biomass C (MBC), and arbuscular mycorrhizal fungi (AMF) colonization rates. After two years, MBC was highest in the control treatments, likely due to greater cover crop biomass on the soil surface at termination. No differences were observed between treatments for SOC, POXC, WSA, PR, or AMF. Increased cotton lint yield was observed in control and mid‐February treatments in 2019, likely due to greater cover crop residues on the soil surface following grazing, which may have conserved soil moisture during the growing season. Peanut yields were unaffected by treatments in 2020. Lack of differences in soil health indicators suggests that integrating winter‐grazing livestock does not negatively nor positively impact selected dynamic soil properties in the short‐term, but more time under grazing treatments is needed to thoroughly evaluate how winter‐grazing livestock impacts soil health and crop yield.

Economic, social, and environmental impacts of cattle on grazing land ecosystems

• Sustainable beef is a socially responsible, environmentally sound, and economically viable product that prioritizes planet, people, animals, and progress. Beef sustainability requires awareness of the complex relationships among these three pillars. • In practice, sustainability to beef farmers and ranchers is about taking care of the animals, land, and water, while being a good neighbor and community member, and maintaining profitability. The beef industry has made improvements across these three areas of sustainability, in all sectors of the industry, from the cow-calf level to the packer phase. • The removal of beef cattle from grazing lands would effectively eliminate the beef industry, which would have a ripple effect on other industries that serve as input suppliers across the beef supply chain, while also eliminating critical social, economic, and environmental services provided by grazing cattle. • We describe the science on the economic, social, and environmental benefits of grazing cattle on grazing lands, and discuss the sustainability impacts of eliminating the beef industry in the U.S.

173 Grazing Cover Crops: Effects of Cattle Removal Date on Forage Production and Cattle Performance

Abstract Use of cool-season annual cover crops through grazing has been shown to be a potential tool in extending the grazing season, while still mitigating environmental risks associated with warm-season row crop production. Although data describing the effects of grazing on soil health are not novel, effects of grazing length on animal performance and cover crop production are limited. The objective was to determine cattle performance and forage production when grazing a cool-season annual cover-crop. Twelve, 1.2-ha pastures were established in a four species forage mix and randomly allocated to be grazed through either mid-February (FEB), mid-March (MAR), or mid-April (APR) with a non-grazed control (CON). Three tester steers were randomly placed in each paddock and a 1:1 forage allowance was maintained in each paddock using put-and-take steers. Animals were weighed every 30 d for determination of average daily gain (ADG). Forage was harvested bi-weekly and analyzed for forage production, neutral detergent fiber (NDF), and acid detergent fiber (ADF). Fiber fractions were measured using an ANKOM fiber analyzer (ANKOM Tech, Macedon, NY). All data were analyzed using MIXED procedure of SAS version 9.4 (SAS Inst., Cary, NC). Differences in forage mass were detected between CON and FEB (3,694.75 vs. 2,539.68 kg/ha; P < 0.003), CON and MAR (3,694.75 vs. 1,823.45 kg/ha; P < 0.001), and CON and APR (3,694.75 vs. 1,976.23 kg/ha; P < 0.001). Differences in total gain/acre were detected between APR and MAR (212.24 vs. 101.74 kg/ha; P < 0.0001), APR and FEB (212.24 vs 52.65 kg/ha; P < 0.0001), and FEB and MAR (101.74 vs. 52.65 kg/ha; P < 0.003). No differences were detected for tester ADG (1.23 kg/day, P = 0.56), NDF (44.9%, P = 0.99), or ADF (27.2%, P = 0.92) among treatments. These results indicate that cattle removal date effected forage yield and total gain/hectare.

Rotational grazing can mitigate ecosystem service trade‐offs between livestock production and water quality in semi‐arid rangelands

Abstract Mitigating ecosystem service (ES) trade‐offs is a key management goal in locations where stakeholders value different and potentially conflicting ecosystem services (ESs). However, studies are not often designed to examine how local management actions address ES trade‐offs, and therefore do not provide options that can alleviate conflict. In semi‐arid rangelands, we examined the potential for managers to mitigate trade‐offs between livestock production and water quality. To move away from solutions that offer cattle removal as a singular management strategy, we examined how cattle presence, plus two elements of rotational grazing—the length of time cattle spend on rangeland (i.e. duration), and the season grazed (i.e. timing), affected stream Escherichia coli (E. coli concentrations). We also modelled how grazing duration and timing affected the ability to meet regulatory benchmarks for water quality throughout a grazing season. Grazing duration controlled the length of time E. coli concentrations were high in streams. In short‐ and medium‐duration systems, E. coli concentrations were high for shorter periods of time than in long‐duration systems, resulting in fewer violations of national and state water quality standards. Stream E. coli concentrations showed a consistent seasonal pattern, starting low in spring, peaking in summer and declining towards fall. Thus, grazing during spring or fall, rather than in summer, reduced the number of days that E. coli levels exceeded water quality standards. Our results suggest that reducing the grazing duration and shifting its timing are complementary strategies that can mitigate the trade‐offs between livestock grazing and water quality without fencing‐off riparian areas or removing cattle from pastures with streams. Synthesis and applications. In this study, we found grazing duration and timing can be used as tools to mitigate ecosystem service (ES) trade‐offs between cattle production and water quality in rangeland streams. Shorter grazing durations reduced the number of days E. coli levels were above regulatory limits, as did grazing that occurred either early or late in the season. These results support the idea that rotational grazing can be an effective strategy to manage water quality in semi‐arid rangelands. They also highlight the need for more grazing studies that incorporate gradients of duration and timing into study designs.

Recovery of the herbaceous component of degraded sagebrush steppe is unimpeded by 75 years of moderate cattle grazing

AbstractUnderstanding the effects of contemporary cattle grazing on herbaceous perennial communities in big sagebrush steppe is important for managing for wildlife habitat, plant diversity, and productivity, yet potentially complicated by legacy impacts of historic, often higher intensity, livestock grazing. Here, we evaluate whether recovery of herbaceous communities in eastern Oregon, USA, after the cessation of intense spring sheep grazing (1935) was affected by moderate cattle grazing in paired plots with or without grazing over the past 75 yr (1936–2011). We tested for the effects of cattle grazing on herbaceous community recovery, as indicated by changes over time in plant density, and composition, as measured by Bray–Curtis dissimilarity. We also included current and prior to sampling year precipitation anomalies, to account for the weather effects, and a random term for pasture location of plot pairs to include potential subtle differences in abiotic environment and grazing management. We further tested whether time since cessation of intense sheep grazing and moderate cattle grazing were associated with convergence or divergence in community composition indicated by changes in evenness, richness, species relative abundance (rank order), and turnover or species appearance or disappearance. Total perennial herbaceous, forb, and grass density increased over time in sites grazed and ungrazed by cattle, though species varied in the direction of their response to contemporary cattle grazing. Community composition metrics indicated convergence over time including increasing evenness, decreasing Bray–Curtis dissimilarity, decreasing shifts in species relative abundance (rank order), and lower rates of species turnover (and gain and loss). Contemporary cattle grazing was not associated with convergence or divergence in composition. Precipitation anomalies for the current or prior water year were only occasionally significant in herbaceous density and community composition change models. Our results indicate similar long‐term recovery trajectories occurred in sites with moderate cattle grazing or removal of all livestock following cessation of intense sheep grazing. Management planning and resource assessment focused on herbaceous perennial communities in sagebrush steppe should seek to separate the impacts of historic from contemporary livestock grazing practices.

Effects of white-tailed deer habitat use preferences on southern cattle fever tick eradication: simulating impact on \u201cpasture vacation\u201d strategies

BackgroundRhipicephalus (Boophilus) annulatus and Rhipicephalus (Boophilus) microplus (southern cattle fever tick; SCFT), collectively known as cattle-fever ticks (CFTs), are vectors of protozoal parasites (Babesia bigemina and Babesia bovis) that cause bovine babesiosis (also known as cattle fever). One traditional strategy for CFT eradication involves the implementation of a “pasture vacation,” which involves removing cattle (Bos taurus) from an infested pasture for an extended period of time. However, vacated pastures are often inhabited by wildlife hosts, such as white-tailed deer (WTD; Odocoileus virginianus), which can serve as alternate hosts for questing CFTs. We hypothesized that the distribution of host-seeking larvae among habitat types post-pasture vacation would reflect habitat use patterns of WTD, and in turn, affect the subsequent rate of pasture infestation by CFT.MethodsWe adapted a spatially explicit, individual-based model to simulate interactions among SCFT, cattle, and WTD as a tool to investigate the potential effects of WTD habitat use preferences on the efficacy of a pasture vacation. We parameterized the model to represent conditions typical of rangelands in south Texas, USA, simulated a 1-year pasture vacation under different assumptions regarding WTD habitat use preferences, and summarized effects on efficacy through (1) time post-vacation to reach 100% of pre-vacation densities of host-seeking larvae, and (2) the ecological conditions that resulted in the lowest host-seeking larval densities following pasture vacation.ResultsLarval densities at the landscape scale varied seasonally in a similar manner over the entire simulation period, regardless of WTD habitat use preferences. Following the removal of cattle, larval densities declined sharply to < 100 larvae/ha. Following the return of cattle, larval densities increased to > 60% of pre-vacation densities ≈ 21 weeks post-vacation, and reached pre-vacation levels in less than a year. Trends in larval densities in different habitat types paralleled those at the landscape scale over the entire simulation period, but differed quantitatively from one another during the pasture vacation. Relative larval densities (highest to lowest) shifted from (1) wood/shrub, (2) grass, (3) mixed-brush during the pre-vacation period to (1) mixed-brush, (2) wood/shrub, (3) grass or (1) wood/shrub, (2) mixed-brush, (3) grass during the post-vacation period, depending on WTD habitat use preferences.ConclusionsBy monitoring WTD-driven shifts in distributions of SCFT host-seeking larvae among habitat types during simulated pasture vacation experiments, we were able to identify potential SCFT refugia from which recrudescence of infestations could originate. Such information could inform timely applications of acaricides to specific refugia habitats immediately prior to the termination of pasture vacations.Graphical

Quantifying responses of dung beetle assemblages to cattle grazing removal over a short-term in introduced Brazilian pastures

Pasture management techniques may affect the biodiversity of insects beneficial to pastures, such as dung beetles. Cattle grazing removal over a short-term is widely used in introduced Brazilian pastures. However, the impact of this management on dung beetles is still unknown. This study evaluated the taxonomic (species richness, abundance, biomass, species composition, Shannon, and Simpson indexes) and functional (functional richness FRic, functional dispersion FDis, functional evenness FEve, and community-weighted means of trait values CWMs) dung beetle assemblages response to cattle grazing removal over a short-in introduced pastures. We sampled dung beetles, with pitfall traps baited with cattle dung and carrion, simultaneously in pastures with constant cattle grazing (control), and one, three, and five months after cattle grazing removal in Aquidauana, Mato Grosso do Sul, Brazil. Taxonomic metrics and FRic, FDis, and FEve did not differ among control and pasture treatments. We found that pastures with one month of cattle removal maintain the same CWM coprophagous diet from the control, and higher CWM biomass in relation to control. Although cattle grazing removal, at least over the short-term, does not cause a negative impact on dung beetle taxonomic metrics and functional diversity indexes, two important traits associated to dung removal are negatively affected after three months of cattle removal. Thus, we suggest that one month of cattle removal to grazing rotational management in introduced Brazilian pastures can be a useful strategy to, besides conserving the grass, also conserving dung beetle diversity, and consequently the ecological functions performed by them.

Contributions of dairy products to environmental impacts and nutritional supplies from United States agriculture

Questions regarding the balance between the contribution to human nutrition and the environmental impact of livestock food products rarely evaluate specific species or how to accomplish the recommended depopulation. The objective of this study was to assess current contributions of the US dairy industry to the supply of nutrients and environmental impact, characterize potential impacts of alternative land use for land previously used for crops for dairy cattle, and evaluate the impacts of these approaches on US dairy herd depopulation. We modeled 3 scenarios to reflect different sets of assumptions for how and why to remove dairy cattle from the US food production system coupled with 4 land-use strategies for the potential newly available land previously cropped for dairy feed. Scenarios also differed in assumptions of how to repurpose land previously used to grow grain for dairy cows. The current system provides sufficient fluid milk to meet the annual energy, protein, and calcium requirements of 71.2, 169, and 254 million people, respectively. Vitamins supplied by dairy products also make up a high proportion of total domestic supplies from foods, with dairy providing 39% of the vitamin A, 54% of the vitamin D, 47% of the riboflavin, 57% of the vitamin B12, and 29% of the choline available for human consumption in the United States. Retiring (maintaining animals without milk harvesting) dairy cattle under their current management resulted in no change in absolute greenhouse gas emissions (GHGE) relative to the current production system. Both depopulation and retirement to pasture resulted in modest reductions (6.8-12.0%) in GHGE relative to the current agricultural system. Most dairy cow removal scenarios reduced availability of essential micronutrients such as α-linolenic acid, Ca, and vitamins A, D, B12, and choline. Those removal scenarios that did not reduce micronutrient availability also did not improve GHGE relative to the current production system. These results suggest that removal of dairy cattle to reduce GHGE without reducing the supply of the most limiting nutrients to the population would be difficult.

Bovine leukemia virus detection and dynamics following experimental inoculation

Bovine leukemia virus (BLV) infects more than 40% of the United States cattle population and impacts animal health and production. Control programs aiming to reduce disease prevalence and incidence depend on the ability to detect the BLV provirus, anti-BLV antibodies, and differences in blood lymphocyte counts following infection. These disease parameters also can be indicative of long-term disease progression. The objectives of this study were to determine the timing and to describe early fluctuations of BLV-detection by qPCR, ELISA, and lymphocyte counts. Fifteen Holstein steers were experimentally inoculated with 100 μL of a blood saline inoculum. Three steers served as in-pen negative controls and were housed with the experimentally infected steers to observe the potential for contract transmission. Five additional negative controls were housed separately. Steers were followed for 147 days post-inoculation (DPI). Infections were detected in experimentally infected steers by qPCR and ELISA an average of 24- and 36 DPI, respectively. Significant differences in lymphocyte counts between experimentally infected and control steers were observed from 30 to 45 DPI. Furthermore, a wide variation in peak proviral load and establishment was observed between experimentally infected steers. The results of this study can be used to inform control programs focused on the detection and removal of infectious cattle.