Continuous Grazing Systems Research Articles

Effects of rumen-protected fat on performance, carcass and meat characteristics, and feeding behaviour of Nellore bulls finished in intensive grazing systems

Context Beef cattle production in the tropics is based on the grazing system. Concentrate supplementation has a significant influence on carcass gain and meat quality. Additionally, the inclusion of some lipid feedstuffs, such as rumen-protected fat (RPF), can increase the net energy for weight gain, and be an alternative to increase the productive performance and carcass traits of grazing beef cattle. Aims This study evaluated the effects of RPF on performance, carcass traits and feeding behaviour of Nellore bulls in an intensive grazing system during the rainy season. Methods Twenty-four Nellore bulls (initial bodyweight of 454.0 ± 46.1 kg) were used in a randomised completed block design, based on initial bodyweight. The animals were distributed in 12 paddocks (two bulls per paddock) in a continuous grazing system and randomly assigned to one of two treatments: control (n = 6), a concentrate without added protected fat provided ad libitum, and RPF (n = 6), a concentrate with the addition of 3% protected fat (Nutricorp, Araras, São Paulo, Brazil) provided ad libitum. Statistical analysis was performed using the MIXED procedure of SAS 9.4 with paddock as the experimental unit (12 paddocks). The principal model included fixed effect of treatment and block as a random effect. For forage characteristics, the experimental period was a considered fixed effect. The study lasted 105 days, and was divided into four periods. At the end of each period, forage collections were performed, bulls were weighed and feeding behaviour was recorded. After 105 days, the bulls were slaughtered in a commercial slaughterhouse, and three 2.54-cm Longissimus dorsi steaks of each animal were collected to evaluate the colour, the chemical and physical composition, and the sensory analysis of the meat. Keys results The inclusion of RPF in the concentrate did not affect (P > 0.05) the final bodyweight, average daily gain, concentrate intake and feed efficiency, but there was a tendency (P < 0.07) for higher carcass weight for the bulls that received RPF. Bulls supplemented with RPF had a greater (P < 0.05) average carcass gain. For meat quality, an effect (P < 0.01) was observed for hue (25.32 and 27.91 for control and RPF, respectively). Conclusions The addition of 3% RPF in the concentrate ration has the potential to improve carcass traits and meat quality of beef cattle in an intensive pasture finishing system. Implications The inclusion of RPF will increase dietary energy density of grazing beef cattle with a tendency to increase carcass gain. This can be an opportunity to increase the production per animal and income of farmers.

An update in Claviceps paspali disease: a comprehensive analysis on field and greenhouse Paspalum spp. Infection.

Paspalum L. is a genus of the Poaceae family, with many species serving as well-adapted forage plants in subtropical climates and continuous grazing systems. However, Claviceps paspali, an ascomycete of the order Hypocreales, represents a major threat to Paspalum species. This fungus induces ergot disease, characterized by the replacement of infected flower seeds with sclerotia, which adversely affects seed production and animal health through mycotoxin production. Although ergot disease is reported in many countries, no totally resistant Paspalum cultivars have been reported for commercial use. This study comparatively evaluated disease development in six Paspalum species under greenhouse conditions with three specific isolates of C. paspali, along with field trials. In addition, field isolates of C. paspali were analyzed for phenotypic characteristics and phylogenetic relationships. Greenhouse evaluation revealed variable susceptibility among Paspalum species, with P. malacophyllum,P. notatum and P. umbrosum being the most resistant. In field trials P. dilatatum showed the highest severity index, while P. umbrosum and P. malacophyllum were less affected. Phenotypic characterization of 22 C. paspali isolates showed variability in pigmentation and growth rates, with PDA being the culture medium where the highest growth rate was observed. Phylogenetic analysis of the isolates identified two well-supported lineages between C. paspali species. This research reports an ergot resistance gradient among Paspalum species, identifying genuine sources of resistance. In addition, virulent isolates of C. paspali potentially useful for rapid screening of accessions or crosses in Paspalum breeding programs were identified.

The LTAR-integrated grazing land common experiment at the Texas Gulf.

Extreme weather and climate events have become more frequent and directly affect the ecological structure and function of integrated grazing lands. While the Great Plains have experienced a long history of regular disturbances from drought and floods, grazing, and fires, the increased frequency and magnitude of these disturbances can reduce ecological resilience, largely depending on management practices. Alternative strategies designed to adaptively manage grazing land resources based on the ecology of the system should increase the resistance and resilience to disturbances when compared to prevailing practices. Determining the ecologic and economic value of alternative strategies will require long-term evaluations across large spatial scales. The Long-Term Agroecosystem Research Network has been established to evaluate the differences between alternative and prevailing practices among 18 strategically located sites and across decadal time scales throughout the continental United States. A key integrated grazing land site within this network is the Texas Gulf located at the Riesel Watersheds in the Blackland Prairie of Central Texas. At this study site, the differences between alternative and prevailing grazing management strategies are now being evaluated. The alternative strategy was designed using a combination of knowledge of the site and species ecology with modern-day tools and technologies. Alternatively, the prevailing practice implements a conventional year-round continuous grazing system with heavy reliance on hay and supplemental protein during winter. Results will provide grazing land managers with economically viable adaptive management choices for increasing ecological resilience following extreme and frequent disturbance events.

PSIV-A-2 Comparison of rising plate meter and total collection methods for forage mass determination of tall fescue

Abstract The objective was to compare estimates of forage mass (FM) determined with a rising plate meter (RPM) with forage mass determined by total collection method. Estimates of FM impact management decisions and give the producer a greater understanding of forage availability for their herd. Traditional methods of FM estimation using a forage ring or quadrat and total collection are labor intensive and time consuming. The RPM tool aims to provide a quicker method of FM estimation without sacrificing accuracy. The reliability of this tool can be impacted by season, species composition, plant growth state, and pasture management. Forage samples were collected from six random locations within both continuous and rotationally grazed systems. The predominant forage species was endophyte-infected tall fescue. A 0.25 m2 forage ring was randomly thrown, then two RPM (Jenquip Manual Platemeter) measurements were collected in the ring, followed by five measurements adjacent to the ring. The RPM determined the compressed sward height (CSH). Subsequently, forage within the ring was hand-clipped at ground level and collected. Samples were dried for 120 h at 55° C to determine forage availability (kg/ha). This process was repeated weekly for 6 wk. Rising plate meter FM was estimated using the equation: kg dry matter (DM)/ha = CSH × 158 + 200. Data were analyzed using the CORR procedure of SAS 9.4. Forage mass estimates from total ring collection method and RPM were weakly correlated in the rotational grazing system (r = 0.26; P = 0.13) and in the continuous grazing system (r = 0.20; P = 0.24). It is important to note that certain sample collection dates had stronger correlations than others. In the rotationally grazed paddocks, FM from RPM were strongly correlated (r ≥ 0.89, P ≤ 0.02) with FM from total ring collection on 6/23/23 and 7/26/23. In the continuously grazed paddocks, FM estimations from RPM were strongly correlated (r ≥ 0.73, P ≤ 0.10) with forage mass from total collection on 7/20/23 and 7/26/23. Variation among the seven RPM readings at each collection site could have contributed to variability. Coefficient of variation ranged from 9 to 48% and averaged 18% for all samples. The inconsistencies in relationship of forage mass determination methods suggests that more variables need to be considered when determining the accuracy of RPM-derived estimates of forage mass of tall fescue.

Impact of diversified grazing systems on milk production, nutrient use and enteric methane emissions in dual-purpose cows.

This study evaluated three continuous grazing systems: Brachiaria Brizantha, Clitoria ternatea and naturalized pastures, complemented with commercial concentrate and C. ternatea silage on milk yield, nutrient use and enteric methane (CH4) emissions. Nine multiparous cows of local Zebu breeds, with an average weight of 448 ± 87kg, were used. The chemical composition of the food was determined. Live weight, milk production, and quality were assessed. Furthermore, serum urea, urea nitrogen, creatinine and glucose in blood were monitored, and nitrogen use efficiency were calculated. Enteric methane (CH4) emissions were estimated using Tier-2 methodology. A 3 × 3 latin square experimental design was applied. The grazing systems of B. brizantha and C. ternatea had the greater live weights of 465.8 and 453.3kg/cow, although the latter is similar to naturalized pasture. Milk production and quality were not affected by grazing system, with the exception of the non-fat solids, where the C. ternatea system was lower (102.2g/kg) than the other grazing systems. The crude protein and N intake, and N excretion in feces and urine were lower in naturalized pasture systems (1139.0g/day). N outputs in milk was high in the C. ternatea system (56.3g/cow/day). The naturalized pastures systems showed the better feed use efficiency (25.7%) compared to others. Serum urea and blood urea nitrogen were greater in B. brizantha followed by C. ternatea. Enteric CH4 emissions were indifferent among grazing systems when expressed as a percentage of greenhouse gases (7.1%). In conclusion, the grazing C. ternatea supplemented with commercial concentrate and C. ternatea silage maintains milk production and quality, reduced cow/day emissions (by 2.5%) and lowered energy losses as methane.

Activity budget and movement patterns of Brown Swiss and Alpine Grey lactating cows during summer grazing in alpine pastures

We used GPS tracking to monitor the grazing patterns of Brown Swiss and Alpine grey lactating cows on an alpine summer pasture (2038 m a.s.l.; SD = 146) in the Dolomites. The pasture (171 ha) was managed with a continuous grazing system (0.52 LU/ha) with morning and evening milking in the barn, guided grazing during the ‘day’, and free grazing at ‘night’. GPS positions were collected from 8 Brown Swiss multiparous and 9 Alpine Grey (4 primiparous and 5 multiparous) cows every two minutes. We inferred behaviours (grazing, resting, walking) from movement metrics, activity sensors and direct behavioural observations. After excluding milking periods, the cows grazed for 8 h/d, rested 10–11 h/d, and walked for 1.5/d. Grazing extended into late evening after milking, and resting prevailed throughout the ‘night’ until the morning milking. When grazing and resting, cows mainly used grasslands as the preferred habitat, but forest and sparse shrub were also used remarkably without consistent negative or positive selection. The pasture use was highly heterogeneous, with higher animal loads close to the barn, especially at night, and in areas with gentler slopes. Alpine Grey primiparous cows were less limited by slope and distance from the barn in their movement but were more selective in habitat use than multiparous cows. Differences between multiparous cows of the two breeds were less marked. Further studies should help understand the internal and external drivers of cattle grazing patterns to devise management practices combining animals’ productivity and welfare with the conservation of the grassland ecosystem services.

Analysis of Labor Productivity in Single and Multi-household Grassland Management Patterns: A Case Study in Maqu County, Qinghai-Tibetan Plateau

This study investigated labor productivity in meat and milk/dairy production within single and multi-household management patterns, based on primary data collected from 156 randomly selected herder households in Maqu County, Tibetan Plateau. The results showed that in the rotational grazing system, herder households in both single and multi-household management patterns achieved higher labor productivity for meat production (70.36 Kg/man-day and 51.21 Kg/man-day, respectively) compared to the overall study households (40.89 Kg/man-day). In contrast, within the continuous grazing system, the single-household management pattern recorded lower labor productivity for meat production (23.04 Kg/man-day). Significantly, regional variations in the distance between pastures and market centers led herder households in the single-household management pattern within the continuous grazing system to achieve superior labor productivity for milk and dairy production (19.74 $/man-day) compared to the overall study households (15.44 $/man-day). In the rotational grazing system, labor productivity for milk and dairy production stood at 12.63 $/man-day for the single-household management pattern and 8.30 $/man-day for the multi-household management pattern. These findings underscore the complexities associated with achieving high labor productivity simultaneously in both meat and milk/dairy production within the same grassland management pattern. While the multi-household management pattern shows promise in reducing labor inputs, it also grapples with challenges in achieving substantial production levels for meat and milk/dairy products. To address these challenges, policymakers should consider follow-up measures that prioritize the simultaneous enhancement of meat and milk/dairy production within the multi-household management pattern. Special attention should be given to reducing the distance between herder households and market centers to facilitate the sale of milk/dairy products. Simply advocating for the broader adoption of the multi-household management pattern may fall short without addressing these production-related hurdles.

The Effect of Continuous Grazing and Rest Rotational Management Systems on Grass Species Composition, Basal Cover and Production on Three Soil Types in the North West Province, South Africa

Rangelands represent the most extensive land cover type on Earth and many people depend on these rangelands for their livelihoods and for the ecosystem services that effect human wellbeing. The impact of grazing on community structure and ecosystem functioning is a key issue for rangeland management in order to maximize livestock production and sustainability of the operations. It is a known fact that soil differences cause differences in the palatability and utilization of grasses. Year-round continuous grazing is the management strategy used in the communal areas of the North West Province of South Africa. In this study the effect of continuous grazing and rest rotation grazing on grass species composition, basal cover and biomass production on different soil types were assessed. From the results it was clear that the effect of continuous grazing was the biggest on the andesitic soils (high clay), then the diabase soils (medium clay), whilst the effect on the quartzite soils was limited to even positive. In the rest rotation system, the effect of soil type on the different variables was negligibly small and the rangeland remained healthy and productive.

Cost-Benefit Analysis of Continuous and Rotational Grazing Systems——A Case Study in Maqu County, China

The rotational grazing systems (RGS) have been advocated as a superior grazing strategy by the Chinese government based on their significant ecological advantage compared to continuous grazing systems (CGS). In practice, however, due to the low-adoption rate of RGS the favorable effect is limited. This study analyzed the total production cost, gross production value, and net margin of CGS and RGS from the perspective of cost benefits. Data were collected from telephone and face-to-face questionnaire survey of 121 randomly sampled households in Maqu County in the Qinghai-Tibet Plateau. The results indicate that although economic benefits were achieved by herder households in both CGS and RGS, the total production costs spent on each sheep unit in RGS were higher than in the overall that of the total households, and the gross production values produced by herder households from livestock products were lower than in the overall that of the total households due to the difference in production practices. This finding suggests that higher production costs may reduce herders’ adoption rate of RGS. Furthermore, the transfer from CGS to RGS also implies that herders may have to face the challenge the change in production practices related to native grass availability, forage seeding, supplementary feeding, livestock transfer, and grazing duration. The policy implications of these findings towards the implementation of rotational grazing systems are as follows: first, policy makers can consider bringing higher economic advantages to the adopters of rotational grazing systems via incentives; Second, policy measures should assist herders to be able to adapt more easily to the production practices in RGS.

The effects of NPK fertilization on hay production and some yield components of crested wheatgrass (Agropyron cristatum) in the dry steppe zone of Eastern Kazakhstan

A three-year-long field experiment was conducted in a continuous grazing system with a variable stocking rate to evaluate effects of increasing NPK fertilization rates (Control- N0P0K0, N60P40K30, and N80P50K40) in crested wheatgrass (Agropyron cristatum) on hay production, some yield components and crude protein concentration in the dry steppe zone of Eastern Kazakhstan. At harvesting, hay production (fresh and dry weight), seeding rate (SER), shrub diameter (SHD), height of generative shoots (HGS), length of root leaves (LRL), weight per bush (WEB), percentage of leaves and vegetative shoots (LVS) and crude protein concentration of crested wheatgrass (Agropyron cristatum) were determined. NPK fertilizer treatments increased hay production, SER, SHD, HGS, LRL, WEB, LVS and crude protein concentration. The results showed that crested wheatgrass at the N80P50K40 treatments achieved a higher hay production and some yield components of crested wheatgrass (Agropyron cristatum) in the dry steppe zone of Eastern Kazakhstan than other NPK treatment and control.

Greenhouse gas balance and mitigation of pasture-based dairy production systems in the Brazilian Atlantic Forest Biome.

Brazilian cattle production is mostly carried out in pastures, and the need to mitigate the livestock's greenhouse gas (GHG) emissions and its environmental footprint has become an important requirement. The adoption of well-suited breeds and the intensification of pasture-based livestock production systems are alternatives to optimize the sector's land use. However, further research on tropical systems is necessary. The objective of this research was to evaluate the effect of Holstein (HO) and Jersey–Holstein (JE x HO) crossbred cows in different levels of pasture intensification (continuous grazing system with low stocking rate–CLS; irrigated rotational grazing system with high stocking rate–RHS), and the interaction between these two factors on GHG mitigation. Twenty-four HO and 24 JE x HO crossbred dairy cows were used to evaluate the effect of two grazing systems on milk production and composition, soil GHG emissions, methane (CH4) emission, and soil carbon accumulation (0–100 cm). These variables were used to calculate carbon balance (CB), GHG emission intensity, the number of trees required to mitigate GHG emission, and the land-saving effect. The number of trees necessary to mitigate GHG emission was calculated, considering the C balance within the farm gate. The mitigation of GHG emissions comes from the annual growth rate and accumulation of C in eucalyptus trees' trunks. The CB of all systems and genotypes presented a deficit in carbon (C); there was no difference for genotypes, but RHS was more deficient than CLS (-4.99 to CLS and −28.72 to RHS ton CO2e..ha−1.year−1). The deficit of C on GHG emission intensity was similar between genotypes and higher for RHS (−0.480 to RHS and −0.299 to CLS kg CO2e..kg FCPCmilk−1). Lower GHG removals (0.14 to CLS higher than 0.02 to RHS kg CO2e..kg FCPCmilk−1) had the greatest influence on the GHG emission intensity of milk production. The deficit number of trees to abatement emissions was higher to HO (−46.06 to HO and −38.37 trees/cow to JE x HO) and to RHS (−51.9 to RHS and −33.05 trees/cow to CLS). However, when the results are expressed per ton of FCPCmilk, there was a difference only between pasture management, requiring −6.34 tree. ton FCPCmilk−1 for the RHS and −3.99 tree. ton FCPCmilk−1 for the CLS system. The intensification of pastures resulted in higher milk production and land-saving effect of 2.7 ha. Due to the reservation of the pasture-based dairy systems in increasing soil C sequestration to offset the GHG emissions, especially enteric CH4, planting trees can be used as a mitigation strategy. Also, the land-save effect of intensification can contribute to the issue, since the area spared through the intensification in pasture management becomes available for reforestation with commercial trees.

Citrus Pulp Replacing Corn in the Supplement Decreased Fibre Digestibility with No Impacts on Performance of Cattle Grazing Marandu Palisade Grass in the Wet-Dry Transition Period.

Simple SummaryDeterioration of forage quality as the dry season approaches has detrimental effects on the performance of cattle grazing tropical grasses unless supplementation strategies are implemented. In this study, corn was replaced by citrus pulp as an energy source to evaluate the effects of supplementation on liveweight performance and metabolic parameters of Bos indicus cattle grazing Urochloa brizantha cv. Marandu in the wet-dry transition period.The wet-dry transition period brings unique challenges to cattle producers in the tropics as the forage quality starts to decrease and animal performance is negatively affected unless supplementation strategies are applied. Two experiments were conducted concomitantly to evaluate the performance and metabolic parameters of cattle supplemented with two different energy sources under a C4 tropical grass continuous grazing system in the wet-dry transition period. In experiment (exp) 1, the liveweight (LW) gain of 42 growing Bos indicus Nellore bulls allocated to 12 paddocks of Uruchloa brizantha cv. Marandu, in a completely randomized block design, was evaluated to compare corn and citrus pulp-based supplements offered at 0.5% LW. Metabolism was evaluated in exp 2 with eight rumen-cannulated Nellore steers in an incomplete replicated Latin square design (RLSD) 4 × 2 (steers × treatment) fed the same two treatments as in exp 1. No differences in animal performance were observed between corn or citrus pulp-based supplements. Rumen pH, ammonia nitrogen, and blood urea nitrogen were lower in the rumen of animals supplemented with citrus pulp. Despite this, there were no differences in total dry matter intake amongst the two energy sources. The neutral detergent fibre digestibility of the diet containing corn decreased, but it neither affected performance nor liveweight gain per area. The findings suggest that corn can be replaced by citrus pulp with neither detrimental effects on animal performance nor indirect effects on pastures productivity.

The influence of protected fat in supplements on the performance and carcass characteristics of Nellore beef bulls in tropical pasture.

The finishing stages for uncastrated Nellore beef cattle on tropical pasture often produce high yielding carcasses with minimal fat cover. This study aimed to evaluate the performance and carcass characteristics of uncastrated Nellore beef bulls fed a diet containing rumen-protected fat during the rainy period for 210days. Eighty Nellore beef bulls with 28months of age, and an initial live weight of 416kg ± 16kg, were allocated into eight paddocks (7.0ha), totaling 56ha, at 10 animals/paddock, in a continuous-grazing system. The pasture characteristics, performance production, loin-eye area (cm2), subcutaneous fat thickness (mm), and rump fat thickness were evaluated. There was no effect (P > 0.05) on the average total weight gain (203.00kg) and average daily gain (0.98kg/day). On the other hand, the subcutaneous fat thickness and rump fat thickness were 42.8% and 49.5% greater, respectively, when the animals were fed a diet containing rumen-protected fat inclusion (P < 0.05). Supplementation with rumen-protected fat provided a thicker fat layer in the carcass of Nellore beef bulls grazing on tropical pasture during the rainy period.

Performance, nutrient use, and methanogenesis of Nellore cattle on a continuous grazing system of Urochloa brizantha and fed supplement types varying on protein and energy sources

Supplementation of grazing cattle may improve forage utilization, methane emission and efficiency of nutrients use. This study aimed to evaluate the effect of different supllementation strategies on performance, metabolic parameters and methane emission in Nellore cattle reared on well-managed marandu palisadegrass (Urochloa brizantha cv Marandu) pastures. Three supplementation strategies consisted of protein and energy sources from traditional ingredients compared to a novel feedstuff: TS) Traditional supplement (protein-energy) composed of ground corn and soybean meal; ES) energy supplement composed of ground corn; and DS) Distiller's coproduct supplement (protein-energy) composed of ground corn and dried distiller grain (DDG). All supplements were offered at 0.3% of body weight (BW). Sixty-nine growing Nellore bulls [251 kg of body weight (BW) ± 13.0 kg] were randomly distributed according to initial BW in nine paddocks (twenty-three animals per treatment, three paddocks per treatment) to evaluate liveweight gain. From these, eighteen bulls (381.83 kg BW ± 16.15 kg) were selected for methane emission measurements (six animals per treatment) using sulfur hexafluoride tracer gas technique. Six rumen cannulated steers (289.5 kg BW ± 19.6 kg) across six paddocks (two per treatment) were used in an incomplete double Latin square design (3 treatments x 4 periods) to evaluate metabolic parameters. Statistical analyses were done using the Mixed Procedure in SAS and adopting significance level at 5%. It was hypothesized that the use of DS or ES, could increase the N use efficiency because of a higher rumen undegradable protein content, and more energy available for microbial synthesis in the rumen, respectively. Overall, there were no differences on animal performance, intake, nutrients digestibility, ruminal parameters, and microbial protein synthesis among treatments indicating that any of the supplemental sources could be utilized. Although, animals in DS had lower urine N excretion. The ES supplement increased methane yield (g/DMI) and the methane conversion factor Ym (% of gross energy intake) when compared to other treatments, but not methane production, which was similar among all treatments.

Avaliação dos sistemas de pastejo em propriedades rurais de leite em Confresa-MT

O manejo correto de uma pastagem é o fator determinante para uma boa produção e resposta por parte do animal. Assim o presente trabalho visou comparar o desenvolvimento dos sistemas rotacionado e extensivo de pastejo em propriedades rurais produtoras de leite do município de Confresa-MT. A metodologia do projeto buscou a aplicação de questionário, coleta de amostras de forragem, e acompanhamento da produção leiteira das doze propriedades escolhidas, as amostras de cada propriedade avaliada foram coletadas e encaminhadas para o laboratório de bromatologia do Instituto Federal de Mato Grosso – Campus Confresa, um total de 36 amostras de diferentes forrageiras avaliadas. Foram analisados três tratamentos, sistema rotacionado de pastejo com dois dias de ocupação, rotacionado com mais de dois dias de ocupação e sistema contínuo de pastejo. Segundo dados estatísticos ao teste de Tukey a 5% o sistema rotacionado com 2 dias de ocupação apresentou resultados superiores em teores de massa verde, massa seca e produtividade leiteira em relação aos demais sistemas. Verificou se que o período de descanso foi fator primordial para tal resultado.

Collaborative Adaptive Rangeland Management, Multipaddock Rotational Grazing, and the Story of the Regrazed Grass Plant

Frequent, severe defoliation reduces grass production and can alter plant species composition in grasslands. Multipaddock rotational grazing has been proposed as a grazing strategy that may reduce the frequency and intensity of defoliation on palatable grass plants without altering stocking rates. Previous studies evaluated this hypothesis using small, homogeneous paddocks and nonadaptive rotation schedules and found small and inconsistent differences between continuous and rotational grazing systems. Using a stakeholder-driven collaborative adaptive management (CAM) framework, we conducted the first ranch-scale experimental investigation into tiller defoliation patterns in the context of adaptive multipaddock rotational grazing. We monitored tiller defoliation frequency and intensity in 10 paired 130-ha pastures assigned to either a collaborative adaptive multipaddock rotational grazing treatment (CARM, one livestock herd) or a season-long continuous grazing treatment (traditional rangeland management [TRM]; 10 separate herds) in shortgrass steppe. Consistent with previous studies, we observed that frequencies of grazing and regrazing on a palatable, cool-season grass (western wheatgrass, Pascopyrum smithii) were much more sensitive to stocking rate than grazing system. Under moderate stocking rates used in both CARM and TRM treatments, roughly two-thirds of western wheatgrass tillers remained ungrazed annually, regardless of grazing system. Thus, season-long rest is present in season-long continuous and rotational grazing systems. Frequencies of tiller regrazing were low (5−15%) and similar between CARM and TRM treatments. Although defoliation patterns were similar between treatments at the whole-ranch scale, CARM enhanced spatial and temporal heterogeneity in defoliation frequencies among individual pastures. Pastures grazed earlier in the season or for longer experienced more defoliation. Managers implementing adaptive, multipaddock rotational grazing could use this heightened and predictable variability to strategically manage impacts of grazing on western wheatgrass at the individual pasture scale. The CAM model enabled our team to identify and directly address key stakeholder hypotheses and resulted in coproduction of management-relevant research.

Combinations of by-products from biodiesel production included in the supplement for finishing heifers on deferred pastures.

We hypothesized that by-products from biodiesel production like crambe meal (Crambe abyssinica) totally replace soybean meal (Glycine max) and crude glycerin could partially replace corn (Zea mays). Our aim was to evaluate different supplements with combinations of crambe meal and crude glycerin replacing soybean meal or corn on performance and carcass traits of finishing heifers. Sixty Nellore heifers 18 months old were used, and 298.96 ± 21.99 kg of body weight allotted in Brachiaria brizantha pastures. All heifers were distributed in a randomized complete block design, with four treatments being the following supplements: corn + soybean meal (CS), corn + crambe meal (CCr), corn + soybean meal + crude glycerin (CSG), corn + crambe meal + crude glycerin + (CCrG). The animals were distributed in four paddocks of 13 hectares each, in a continuous grazing system. We evaluated pasture characteristics, intake, performance, carcass traits, characteristics, and centesimal composition of Longissimus thoracis muscle. There was an effect (P < 0.05) of inclusion of crambe meal on the performance of the animals for slaughter weight and daily gain. The supplement containing corn + soybean meal (CS) presented better conversion rates and food efficiency. There was an effect of inclusion of crambe meal and crude glycerin on the centesimal composition of Longissimus thoracis muscle. The use of crambe meal and crude glycerin as alternative sources from the agro-industry of biodiesel in concentrate supplement for finishing heifers in pastures can promote positive effects related to productive performance and carcass characteristics.

Soil carbon dynamics in Brazilian Atlantic forest converted into pasture‐based dairy production systems

AbstractThe conversion of Brazilian tropical forests into pastureland was a complex process, potentially harmful to the environment, heightened by degraded grazing systems that did not ensure sustainability and affected the ecosystem resilience. This study was conducted to determine the long‐term changes in soil C stocks in native forest (FOR) converted to pasture‐based dairy systems (continuous grazing system with low stocking rate–CLS; rotational grazing system with high stocking rate–RHS). Soil samples were analyzed for texture, C, organic matter (OM), bulk density (BD), C stock, and carbon accumulation rates (CAR) in 0‐to‐5‐, 5‐to‐10‐, 10‐to‐20‐, 20‐to‐30‐, 30‐to‐40‐, 40‐to‐60‐, 60‐to‐80‐, and 80‐to‐100‐cm depths in six trenches. Bulk density was higher in RHS compared with CLS and FOR in most of the soil layers. In the 0‐to‐5‐cm layer, C and OM were greater in CLS. Carbon contents were similar in RHS and FOR, whereas OM was higher in FOR. Intensification increased BD, reduced OM, and did not affect C content in the 0‐to‐5 cm layer. For all treatments, C stock and CAR were higher in the 0‐to‐100 cm (136.73 Mg ha−1 and 0.4252 Mg ha−1 yr−1) than the 0‐to‐30 cm (61.79 Mg ha−1 and 0.0447 Mg ha−1 yr−1) layer. The soil C stock remained equal for both pastureland and presented a positive CAR in relation to the forest, working as C sinks. The RHS presented the greatest forage yield, carrying capacity and milk yield. This management resulted in a land‐saving effect of 2.7 ha for each hectare of high intensified pasture.

Effects of 27 mo of rotational vs. continuous grazing on horse and pasture condition.

The objective of this study was to determine whether rotational grazing generates horse, pasture, or cost benefits over continuous grazing. The study established two replicates (1.57 ha each) of rotational (R; four grazing sections and a stress lot per replicate, where horses were fed a moderate quality grass hay at 2% of body weight when not grazing) and continuous (C) grazing systems (treatments). Twelve Standardbred mares were grazed for an overall stocking rate of 0.52 ha/horse (n = 3 in each pasture). Recommended management practices for each grazing system were followed for 27 mo including three grazing seasons. Samples were collected monthly between 0800 and 1000. Results were analyzed in SAS (V9.4) using mixed model repeated-measures analysis of covariance, chi-square tests of association, and two-sample t-tests. Alpha level was set at P < 0.05. The C horses were maintained on pasture for 100% of the study duration (844 d; August 1, 2014 to November 22, 2016), while R horses had access to pasture for approximately half of this time (408 ± 33 d). The average length of grazing bout per rotational grazing section during the grazing season increased numerically each year from 7.88 ± 0.76 d in 2014, 10.0 ± 0.61 d in 2015, and 10.9 ± 0.80 d in 2016. Average horse body condition score (BCS) and body fat differed by treatment, with C horses (BCS 6.3 ± 0.05, 17.9 ± 0.15% body fat) greater than R horses (BCS 5.9 ± 0.05, 16.8 ± 0.15% body fat). Both sward height and herbage mass were greater in R (11.8 ± 0.1 cm tall; 1,513 ± 41 kg/ha) than C pastures (6.9 ± 0.1 cm tall; 781 ± 35 kg/ha). The R pastures had higher proportions of vegetative and total cover, planted grasses (tall fescue and orchardgrass), and weeds but lower proportions of grass weeds (nonplanted grasses) and other (rocks, litter, bare ground, etc.) as compared with C pastures. Digestible energy, acid detergent fiber, and calcium were higher in R vs. C pastures; however, crude protein was lower in R vs. C pastures. There were no significant differences between treatments for average monthly amount of hay fed (C, 597 ± 34.1 vs. R, 659 ± 34.1 kg) or average monthly pasture maintenance cost (C, $17.55 ± 3.14 vs. R, $20.50 ± 3.14). This study is one of few replicated experiments comparing the effects of rotational and continuous grazing for horses on pasture quality, horse condition, and production costs. The results here support the recommendation of rotational grazing for production, environmental, and ecological purposes.

Plant diversity and botanical composition in an Atlantic heather-gorse dominated understory after horse grazing suspension: Comparison of a continuous and rotational management

Floristic diversity changes substantially depending on the type of land management. We evaluated the impact of a continuous (CG) and rotational (RG) grazing system on the dynamics of plant diversity and community composition in a heather-gorse understory after a two and six-year pause from horse grazing. Previously grazed sites had higher total and rare species richness and diversity than ungrazed (UN), regardless the type of grazing system. The positive impact of previous grazing on species richness was higher in CG and continued after six years in both grazing systems. Seven species of high conservation interest in heathlands were present in the studied areas. Most of them were associated to CG management and none was exclusively in RG. The reduction of the shrub component by previous horse grazing led to a decrease of gorse dominance, thus potentially reducing fire risk and increasing plant diversity. The extent of the positive effect of horse grazing controlling excessive accumulation of combustible material and favoring species richness differed when relative abundance of species, and not solely the number of species, was taken into account (Simpson’s dominance increased and Pielou’s evenness decreased after six years). Overall, the effects of previous rotational and continuous grazing on plant diversity in an Atlantic heather-gorse dominated plant community were still apparent 2 or 6 years after grazing interruption, although declined after the six-year grazing interlude. Rotational management revealed a slight advantage upon the control of gorse biomass long term, and assisted to maintain the relative abundance of species more evenly over time. The alpha and beta diversity indices confirmed that plant diversity similarity between rotational and continuous management increased after six years.