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Rangelands in arid and semi-arid regions are the main source of livestock feed. The fragmentation of these ecosystems by continuous grazing gives rise to the modification of ecological processes, which alters the structure and functionality of plant communities. Therefore, the use of geographic information systems and the analysis of satellite images are important to monitor spatial changes and to evaluate these areas in the Tamaulipan Highlands of northeastern Mexico. This work aimed to evaluate the current state of the rangelands and to determine the percentage of modified areas as well as propose the time of permanence, succession, or recovery of five different areas destined for rangelands. For the analysis, Landsat satellite scenes from the period 1973–2020 were used: they were classified into four categories using segmentation and maximum likelihood analysis, as well as a cross-tabulation method to determine the degree of succession. An increase in rangelands was found in three of the five areas analyzed in the period from 1973 to 2020. As rangeland areas increase, the coverage of pine–oak forests, submontane–thorny scrub, and anthropogenic areas, decreases. The disturbance processes were not linear, and the increase in rangeland areas was greater in xerophilous scrub and secondary vegetation. This work is the first contribution that evaluates the changes in land use and cover in grazing areas compromised by continuous grazing in the Tamaulipan Highlands and Mexico. In addition, the results indicate the importance of performing studies based on the coexistence of wildlife and livestock as well as the interaction between soil degradation and plant diversity with the increase in rangelands.

On-farm product differentiation represents a valuable opportunity for mountain agriculture. Consumers appreciate mountain products’ characteristics, but when signalling instruments are lacking, consumers might not be able to recognize (and pay for) them. Through a choice experiment, this paper considers consumers’ willingness to pay for three attributes (mountain origin through the EU Mountain Product term; local endangered landrace; agroecosystems stewardship through rotational grazing). It considers lamb meat production and North-Eastern Italian consumers, also exploring attitudes towards food and differences across groups of consumers. The highest willingness to pay is associated with the EU Mountain Product term, but communication strategies and public information provision are needed to enhance consumers’ overall knowledge.

Adaptive multi-paddock (AMP) grazing has been purported as a ‘climate-smart’ practice due to its potential to mitigate greenhouse gas emissions by increasing soil organic carbon (SOC) stocks, although contrasting results have been observed. The goal of this study was to compare SOC stocks between neighboring AMP and non-AMP beef farms in southern Ontario while simultaneously evaluating the stability and origin of potential SOC stock differences. Higher SOC and total nitrogen stocks were found in AMP, along with higher mineral-associated carbon stocks in the top 15 cm under AMP, indicating greater SOC stability with the grazing strategy. Abundances of microbial phospholipid fatty acids (PLFA) classes via gas chromatography were significantly higher in AMP than non-AMP with no change in community structure or community ratios. No differences were detected in autoclaved citrate-extractable protein, a novel soil health test. This research shows that in southern Ontario and other temperate pastures, AMP grazing should be encouraged over continuous grazing to increase SOC stocks and stability.

Integrating warm-season grasses into cool-season equine grazing systems can increase pasture availability during summer months. The objective of this study was to evaluate effects of this management strategy on the fecal microbiome and relationships between fecal microbiota, forage nutrients, and metabolic responses of grazing horses. Fecal samples were collected from 8 mares after grazing cool-season pasture in spring, warm-season pasture in summer, and cool-season pasture in fall as well as after adaptation to standardized hay diets prior to spring grazing and at the end of the grazing season. Random forest classification was able to predict forage type based on microbial composition (accuracy: 0.90 ± 0.09); regression predicted forage crude protein (CP) and non-structural carbohydrate (NSC) concentrations (p < 0.0001). Akkermansia and Clostridium butyricum were enriched in horses grazing warm-season pasture and were positively correlated with CP and negatively with NSC; Clostridum butyricum was negatively correlated with peak plasma glucose concentrations following oral sugar tests (p ≤ 0.05). These results indicate that distinct shifts in the equine fecal microbiota occur in response different forages. Based on relationships identified between the microbiota, forage nutrients, and metabolic responses, further research should focus on the roles of Akkermansia spp. and Clostridium butyricum within the equine hindgut.

This study investigated the changes in soil physical properties after the abandonment of haypastures dominated by Helictotrichon pubescens and subsequent colonization by successional grasses Brachypodium pinnatum and Calamagrostis epigejos. We also investigated if there are linear relationships among the soil physical properties in the studied soils, and the results of the soil chemical property analysis were used as an aid in the interpretation of these relationships. The studied soil was calcocambisol on limestone. Soil samples were collected in disturbed and undisturbed state, and the differences among them were analysed by Mann-Whitney U test, whereas the relationships between soil properties were analysed with simple linear regression models. Soil solid particle density was higher in the B horizons of successional grasslands (median=2.61 g/cm3) than in those of haypastures (median=2.54 g/cm3). The A horizons of haypastures were barely 2–3 cm deep, whereas under successional grasses their depth reached as much as 25 cm. At the same soil depth (10–12 cm), the soil colonized by successional grasses had higher total porosity (median=53.3%) and lower bulk density (median=1.18 g/cm3) than those of haypasture soil (medians of 45.1% and 1.41 g/cm3, respectively). Soil total porosity and water holding capacity were positively linearly associated (r2= 0.71, P, U ovom istraživanju analizirane su promjene fizikalnih svojstava tla nakon zapuštanja livadnih pašnjaka s dominacijom vrste Helictotrichon pubescnens, te posljedičnog zarastanja sukcesijskim travama Brachypodium pinnatum i Calamagrostis epigejos. Također, utvrđeno je postoje li linearni odnosi između fizikalnih svojstava tla, dok su rezultati kemijskih analiza korišteni za interpretaciju tih odnosa. Istraživanja su provedena na kalkokambisolu na vapnencu, a tlo je uzorkovano u narušenom i prirodnom stanju. Razlike između fizikalnih svojstava tla analizirane su pomoću Mann-Whitney U testa, a odnosi između fizikalnih svojstava tla analizirani su pomoću jednostavnih linearnih regresija. S obzirom na profile tla, B horizonti sukcesijskih travnjaka pokazali su veću gustoću čvrstih čestica (medijan=2.61 g/cm3) od onih u livadnim pašnjacima (medijan=2.54 g/cm3). A horizonti livadnih pašnjaka bili su jedva 2–3 cm duboki, dok se njihova dubina u sukcesijskim travnjacima produbila i do 25 cm. Iz praktične perspektive, na istoj dubini tla (10–12 cm), tla sukcesijskih travnjaka imala su veći ukupni porozitet (medijan=53,3%) od onoga u tlima livadnih pašnjaka (medijan=45.1%) te manju volumnu gustoću (medijan=1.18 g/cm3) od one u tlima livadnih pašnjaka (medijan=1.41 g/cm3). Ukupni porozitet i retencijski kapacitet tla za vodu pokazali su pozitivnu međusobnu linearnu povezanost (r2= 0.71, P

We compared animal and vegetation responses of a 13 600-ha area under holistic grazing management (HGM) with a similar area under continuous grazing (CGM) in a Patagonian station. Limitations were a dry 2012 −2016 experimental period, poorer soils, and grazing of native guanacos (Lama guanicoe) in the HGM area. Forage standing crop in this area before the experience was lower and remained so during the study: (194 ±31 HGM vs. 244 ±33 kg dry matter . ha −1 CGM). Six monitoring sites showed similar and remarkable (though mostly nonsignificant) vegetation improvements in total cover (10.6% HGM vs. 10.9% CGM) and cover of short palatable grasses (21.4% vs. 23.9%, respectively). Species richness showed small changes ( −1 vs. −6%), bare soil interpatches decreased ( −11.9 vs. −5.4%), and land function indicators of Stability (5.4% vs. 9.9%), Infiltration (12.4% vs. 12.0%), and Nutrient recycling (4.2% vs. 20.6%) increased. Tussock cover changed significantly with grazing management, as it decreased −6% (ns) in HGM and grew 42% ( P = 0.03) under CGM, probably due to coarse tussock forage consumption in HGM. Sheep under HGM were 15% lighter (43.9 ±0.5 HGM vs. 51.7 ±0.5 kg . ewe −1 CGM P < 0.001), ewes scored 28% lower body condition (1.60 vs. 2.25, P < 0.001), and lambing rates were 36% lower (48.3 ±2.1% vs . 74.2 ±1.9%). Rotation ended in 2015 as a consequence of low lambing rates, and sheep body condition and reproductive rates recovered to similar values in both areas. Positive vegetation changes in both areas may be driven by residual effects of destocking 3 decades ago and show that improvement is possible using moderate stocking rates. Although it could be argued that rest periods of HGM may be positive in the long term, its negative effects on animal production should be addressed, and fast regeneration using intense management in these severely restricted habitats should not be expected. Slow, persistent progress under careful management seems achievable under both grazing systems. EEA Santa Cruz Fil: Oliva, Gabriel Esteban. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina. Fil: Oliva, Gabriel Esteban. Universidad Nacional de la Patagonia Austral. Unidad Académica Río Gallegos; Argentina. Fil: Ferrante, Daniela. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina. Fil: Ferrante, Daniela. Universidad Nacional de la Patagonia Austral. Unidad Académica Río Gallegos; Argentina. Fil: Cepeda, Carla Tamara. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina. Fil: Humano, Gervasio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina. Fil: Puig, Silvina. Actividad Privada. Estancia Los Pozos. Santa Cruz; Argentina

Gastrointestinal nematode (GIN) parasites in grazing cattle are a major cause of production loss and their control is increasingly difficult due to anthelmintic resistance and climate change. Rotational grazing can support control and decrease reliance on chemical intervention, but is often complex due to the need to track grazing periods and infection levels, and the effect of weather on larval availability. In this paper, a simulation model was developed to predict the availability of infective larvae of the bovine GIN, Ostertagia ostertagi, at the level of individual pastures. The model was applied within a complex rotational grazing system and successfully reproduced observed variation in larval density between fields and over time. Four groups of cattle in their second grazing season (n = 44) were followed throughout the temperate grazing season with regular assessment of GIN faecal egg counts, which were dominated by O. ostertagi, animal weight and recording of field rotations. Each group of cattle was rotationally grazed on six group-specific fields throughout the 2019 grazing season. Maps and calendars were produced to illustrate the change in pasture infectivity (density of L3 on herbage) across the 24 separate grazing fields. Simulations predicted differences in pasture contamination levels in relation to the timing of grazing and the return period. A proportion of L3 was predicted to persist on herbage over winter, declining to similar intensities across fields before the start of the following grazing season, irrespective of contamination levels in the previous year. Model predictions showed good agreement with pasture larval counts. The model also simulated differences in seasonal pasture infectivity under rotational grazing in systems that differed in temperature and rainfall profiles. Further application could support individual farm decisions on evasive grazing and refugia management, and improved regional evaluation of optimal grazing strategies for parasite control. The integration of weather and livestock movement is inherent to the model, and facilitates consideration of climate change adaptation through improved disease control.

The quality of ryegrass–clover pasture was investigated between August (winter: start of calving) and November (spring: end of breeding) on pasture-based dairy farms (>85% of total feed from pasture) that had short (n = 2, Farms A and B; winter ~30 days, spring ~20–25 days) or long (n = 2, Farms C and D; winter ~35 days, spring ~25–30 days) grazing rotations to determine whether quality was affected by grazing rotation length (RT). Weekly assessments of pasture growth and herbage quality were made using a standardised electronic rising plate meter, and near-infrared spectroscopy, respectively. Data were subjected to repeated measure mixed model analysis, in which herbage quality was the outcome variable. The highest pre-grazing dry matter (PGDM) and height, post-grazing dry matter (DM) and height, and number of live leaves per tiller (leaf regrowth stage, LS) were present in late spring. Neutral detergent fibre (NDF), acid detergent fibre (ADF), metabolisable energy (ME), and organic matter digestibility (OMD) were positively correlated to each other (r2 ≥ 0.8) whilst ADF and lipid, and ADF and OMD were negatively correlated (r2 ≥ −0.8; p < 0.01). Metabolisable energy content was negatively correlated with ADF and NDF (r2 = −0.7, −0.8, respectively), and was inversely related to PGDM. Metabolisable energy was higher (p < 0.05) in farms with shorter (overall mean: 11.2 MJ/kg DM) than longer (10.9 MJ/kg DM) RT. Crude protein was also inversely related to PGDM and was higher with shorter (23.2% DM) than longer (18.3% DM; p < 0.05) RT. Pre-grazing DM affected the amount of pasture that was grazed and, hence, the amount of DM remaining after grazing (post-grazing DM or residual), so that PGDM was correlated with post-grazing height and residual DM (r2 = 0.88 and 0.51, respectively; both p < 0.001). In conclusion, RT, LS, and PGDM during winter and spring influenced the herbage quality, therefore, better management of pastures may enhance the productivity of dairy cows.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES The livestock system in Rio Grande do Sul has undergone several changes in its structure, mainly due to the increase in agricultural activities, reducing the areas destined for livestock. Even with the reduction of the grazing area, the size of the beef cattle herd in the state has remained constant over the years. This fact indicates that pasture management techniques that increase the stocking rate, without prejudice to individual performance, should be better studied. Among these techniques are the grazing method with rotational stocking and the provision of supplements for grazing animals. The experiment was carried out in an area belonging to the Animal Science Department of the Federal University of Santa Maria, with field evaluations from July to November 2017. The characteristics of ryegrass pasture, productive performance, forage intake and the ingestive behavior of beef heifers in ryegrass (Lolium multiflorum Lam.) pasture, under two grazing methods (continuous and rotating) and with or without the supply of whole corn grain (0 and 0.76% of body weight) (PC)) as a supplement. The animals evaluated were Angus heifers with a mean initial age of seven months and 150±4.6 kg BW. The experimental design used was complete randomized blocks, with repeated measurements in time, with four treatments and three area replications. Beef heifers in ryegrass, under the rotational or continuous grazing method and receiving 0.76% of the body weight of corn or not, change the way of searching in the pasture harvest process, maintain the same grazing, rumination and idle times and provides similar pasture intake, total intake of crude protein and neutral detergent fiber, resulting in equal individual weight gain of the animals. Rotational grazing for beef calves in the rearing phase provides an increase in stocking rate and consequently in weight gain per area (GPA). The use of 0.76% of body weight of corn grain in ryegrass pasture provides an increase in stocking rate, in GPA, greater gain in croup height and greater gain in body condition score. O sistema pecuário no Rio Grande do Sul tem passado por diversas modificações na sua estrutura, principalmente pelo incremento das atividades agrícolas, reduzindo as áreas destinadas à pecuária. Mesmo com a redução da área pastoril, o tamanho do rebanho de bovinos de corte, no estado, tem se mantido constante ao longo dos anos. Esse fato indica que técnicas de manejo da pastagem que aumentem a taxa de lotação, sem prejuízo do desempenho individual, devem ser melhor estudadas. Dentre estas técnicas estão o método de pastejo com lotação rotacionada e o fornecimento de suplementos para os animais em pastejo. O experimento foi desenvolvido em área pertencente ao Departamento de Zootecnia da Universidade Federal de Santa Maria, com as avaliações de campo no período de julho a novembro de 2017. Foram avaliadas as características da pastagem de azevém, o desempenho produtivo, a ingestão de forragem e o comportamento ingestivo por de bezerras de corte em pastagem de azevém (Lolium multiflorum Lam.), sob dois métodos de pastoreio (contínuo e rotativo) e com ou sem o fornecimento de grão de milho inteiro (0 e 0,76% do peso corporal (PC)) como suplemento. Os animais avaliados foram bezerras Angus com idade média inicial de sete meses e 150±4,6 kg de PC. O delineamento experimental utilizado foi o de blocos completos ao acaso, com medidas repetidas no tempo, com quatro tratamentos e três repetições de área. Bezerras de corte em azevém, sob o método de pastoreio rotativo ou contínuo e recebendo 0,76% do peso corporal de milho ou não, mudam a forma de busca no processo de colheita do pasto, mantem iguais tempos de pastejo, ruminação e ócio e proporciona semelhante ingestão de pasto, ingestão total de proteína bruta e de fibra em detergente neutro, resultando em igual ganho de peso individual dos animais. O pastoreio rotativo para bezerras de corte na fase de recria, proporciona um incremento na taxa de lotação e consequentemente no ganho de peso por área (GPA). A utilização de 0,76% do peso corporal de grão de milho em pastagem de azevém proporciona um incremento na taxa de lotação, no GPA, maior ganho de altura de garupa e maior ganho de escore de condição corporal.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES Elephant grass has high forage potential and adaptation capacity in tropical and subtropical regions. It is usually grown intensively and fertilized with high doses of mineral fertilizers. This strategy results in high production costs and environmental impacts. The objective of this study was to evaluate different grazing systems with elephant grass in organic and conventional production systems that use of low amounts of inputs. The treatments consisted of four grazing systems: (i) one in organic production, in a polyculture, and in association with other spontaneous growth grasses and three in conventional production, (ii) in a monoculture; (iii) in a polyculture, in association with other grasses; and (iv) in association with other grasses + pinto peanut. In all the polyculture systems, elephant grass was planted in rows, and between the rows, annual ryegrass was introduced. The uniform criterion among the grazing systems was the level of nitrogen fertilization (120 kg of N/ha per year). Forage samples were collected before and after grazing to evaluate plant and animal responses. In the grazing system in organic production, there was a better distribution of forage between the periods of the year. In comparison to the other systems, the conventional production system with a monoculture of elephant grass had a higher forage production, with an irregular distribution during the year. In comparison to in the polyculture system without legume, in the system with grass-legume, there was higher forage production, with better nutritional value. O capim-elefante apresenta alto potencial forrageiro e elevada adaptação em regiões tropicais e subtropicais. Normalmente é cultivado com elevadas doses de fertilizantes minerais. Essa estratégia implica em custos de produção e impactos ambientais elevados. O objetivo desta pesquisa foi avaliar sistemas forrageiros baseados no uso de capim-elefante, cultivado nos modelos de agricultura orgânica e convencional, com baixo uso de insumos. Os tratamentos foram constituídos por quatro sistemas forrageiros: (i) um sob produção orgânica, em policultivo, em associação com outras gramíneas de crescimento espontâneo; e três sob produção convencional, (ii) em monocultivo; (iii) em policultivo, em associação com outras gramíneas; e (iiii) em associação com outras gramíneas + amendoim forrageiro. Em todos os sistemas em policultivo, o capim-elefante foi plantado em linhas, e nas entrelinhas fez-se a introdução de azevém anual. O critério de uniformização dos sistemas forrageiros foi o nível de adubação nitrogenada (120 kg/ha/ano de N). Amostras de forragem foram coletadas antes e após os pastejos para avaliar as respostas de plantas e animais. No sistema forrageiro de produção orgânica verificou-se melhor distribuição da produção de forragem entre os períodos do ano. Na produção convencional, com cultivo do capim-elefante em monocultivo, constatou-se maior produção de forragem, com distribuição irregular durante o ano. No sistema de consórcio, verificou-se maior produção de forragem, com melhor valor nutritivo, em relação ao sistema em policultivo, sem leguminosa. Os resultados demonstram que o capim-elefante adapta-se bem, tanto na agricultura orgânica quanto na convencional, valendo-se do uso de baixos insumos.

Rotational grazing is a management practice in which livestock are cycled through multiple fenced grazing areas (paddocks) in order to manage forage production, forage quality, animal health, and environmental quality. USDA, Natural Resources Conservation Service (NRCS) and other organizations promote rotational grazing as an important grazing practice for providing improved environ-mental outcomes, relative to continuous grazing, in which livestock are not cycled between grazing areas. USDA, NRCS provides financial assistance for rotational grazing and related management practices through the Environmental Quality Incentives Program (EQIP), the Conservation Stewardship Program (CSP), and technical assistances through the Conservation Technical Assistance (CTA) program. Despite the breadth of support for rotational grazing, only limited information is available on the prevalence of rotational grazing and the variation in how producers implement the practice, including details on how frequently or “intensively” grazing operations rotate livestock between paddocks and how outcomes such as stocking density and cost relate to system characteristics. This study uses data from the 2018 Agricultural Resource Management Survey Cattle and Calves Cost and Returns Report to fill this information gap. The study finds that about 40 percent of cow-calf operations use rotational grazing, but adoption rates vary by production regions. Most rotational grazing systems are relatively simple. Only 40 percent of cow-calf operations that report using rotational grazing operations use an intensive rotational grazing schedule.

In the context of a growing population, beef production is expected to reduce its consumption of human-edible food and its contribution to global warming. We hypothesize that implementing the innovations of fast rotational grazing and redesigning existing production systems using crossbreeding and sexing may reduce these impacts. In this research, the bio-economic model FarmDyn is used to assess the impact of such innovations on farm profit, workload, global warming potential, and feed-food competition. The innovations are tested in a Belgian system composed of a Belgian Blue breeder and a fattener farm, another system where calves raised in a French suckler cow farm are fattened in a farm in Italy, and third, a German dairy farm that fattens its male calves. The practice of fast rotational grazing with a herd of dairy-to-beef crossbred males is found to have the best potential for greenhouse gas reduction and a reduction of the use of human-edible food when by-products are available. Crossbreeding with early-maturing beef breeds shows a suitable potential to produce grass-based beef with little feed-food competition if the stocking rate considers the grassland yield potential. The results motivate field trials in order to validate the findings.

High doses of nitrogen (N) fertiliser input on permanent pastures are crucial in terms of N surplus and N losses. Quantitative analyses of the response of plant functional traits (PFT) driving crop growth rate (CGR) under low N input are lacking in frequently defoliated pastures. This study aimed to understand the significance of PFTs for productivity and N uptake in permanent grasslands by measuring dynamics in tiller density (TD), tiller weight (TW), leaf weight ratio (LWR), leaf area index (LAI), specific leaf area (SLA), as well as leaf N content per unit mass (LNCm) and per unit area (LNCa) in perennial ryegrass (Lolium perenne)-dominated pastures, in a simulated rotational grazing approach over two consecutive growing seasons. Annual N application rates were 0, 140 and 280 kg N ha−1. The phenological development of perennial ryegrass was the main driver of CGR, N uptake and most PFTs. The effect of N application rate on PFTs varied during the season. N application rate showed the greatest effect on TD, LAI and, to a lesser extent, on SLA and LNCm. The results of this study highlight the importance of TD and its role in driving CGR and N uptake in frequently defoliated permanent pastures.

High doses of nitrogen (N) fertiliser input on permanent pastures are crucial in terms of N surplus and N losses. Quantitative analyses of the response of plant functional traits (PFT) driving crop growth rate (CGR) under low N input are lacking in frequently defoliated pastures. This study aimed to understand the significance of PFTs for productivity and N uptake in permanent grasslands by measuring dynamics in tiller density (TD), tiller weight (TW), leaf weight ratio (LWR), leaf area index (LAI), specific leaf area (SLA), as well as leaf N content per unit mass (LNCm) and per unit area (LNCa) in perennial ryegrass (Lolium perenne)-dominated pastures, in a simulated rotational grazing approach over two consecutive growing seasons. Annual N application rates were 0, 140 and 280 kg N ha−1. The phenological development of perennial ryegrass was the main driver of CGR, N uptake and most PFTs. The effect of N application rate on PFTs varied during the season. N application rate showed the greatest effect on TD, LAI and, to a lesser extent, on SLA and LNCm. The results of this study highlight the importance of TD and its role in driving CGR and N uptake in frequently defoliated permanent pastures.

High input dairy farms that are located on sandy soils in northwest Europe are predisposed to substantial nitrate leaching during a surplus of winter precipitation. Leys within integrated crop-livestock systems play an important role in soil fertility, soil C sequestration and soil N mineralization potentials. Therefore, leys are a feasible option that can be utilized to reduce local N losses to the environment, especially following maize grown for silage. We hypothesize that grass-clover leys ensure low nitrate leaching losses even when grazed intensively. The extent to which NO3-leaching occurred across seven different pasture management systems in terms of their sward composition, cutting, grazing, fertilization and combinations thereof was investigated in integrated animal-crop grazing systems over three winter periods (2017/2018, 2018/2019 and 2019/2020). The observed grazed systems were comprised of cut-used- and grazed grass-clover swards (0, 1 and 2 years after establishment following cereals), a catch crop grazed late in the year as well as a cut-used permanent grassland for comparison. Overall, all treatments resulted in nitrate leaching losses that did not exceed the WHO-threshold (25 mg nitrate/L). The highest level of NO3-leaching was observed in the catch crop system and the lowest in cut-used permanent grassland, with NO3-N losses of 19.6 ± 5.3 and 2.1 ± 0.3 kg NO3-N ha−1 year−1. Annual herbage yields were in the range of 0.9 to 12.4 t DM ha−1 and nitrogen yields varied between 181 ± 51 and 228 ± 66 kg N ha−1 during the study period. The highest herbage-N-yields were observed from the 1- and 2-year-old grass-clover leys. The highest N-field-balance was observed for the grazed leys and the lowest for the cut-used permanent grassland. However, no correlation was found between the highly positive field-N-balance and the amount of NO3-leached. This indicates a high N carry-over from grass-clover swards to the subsequent cash crop unit instead of increasing the risk of groundwater contamination from grazed leys in integrated animal crop-systems and underlines the eco-efficiency of dairy farming based on grazed ley systems.

En este trabajo se analiza la adopción tecnológica en el sistema pastizal de 10 fincas intervenidas bajo un proyecto de mejoramiento de la ganadería doble propósito en el estado Yaracuy, durante el periodo 2010-2011. La metodología empleada se basó en el diagnóstico inicial de las condiciones existentes en los potreros y a partir de este se diseñó e implementó un plan de acción durante 18 meses orientado al mejoramiento de las deficiencias encontradas; posteriormente, se evaluó el impacto logrado. Entre los indicadores valorados, destacaron, por sus altos porcentajes de adopción, la modulación de potreros (80 %), pastoreo rotativo (80 %) y control de malezas (70 %); seguidamente, se ubicaron el establecimiento de bancos proteicos (50 %) y energéticos (50 %), la fertilización (50 %) y la renovación anual de pasturas (40 %). Los indicadores con menores cambios logrados fueron el tamaño de los potreros (20 %) y el uso frecuente de cercas vivas (20 %). A partir de la estadística multivariada (análisis de conglomerado jerárquico), se lograron definir cuatro grupos de fincas de acuerdo al nivel tecnológico alcanzado, G1: fincas de baja adopción tecnológica (20 %); G2: fincas en transición tecnológica (40 %); G3: fincas con amplia adopción tecnológica (20 %) y G4: fincas vitrinas tecnológicas (20 %). Al tomar en cuenta el alto porcentaje de receptividad a los cambios por parte de los productores, se puede considerar de suma importancia el mejoramiento del sistema pastizal dentro de las fincas.

The present study was to evaluate the weight gain of bovinesin three animal loads with two grazing systems and three levels of grazing, furthermore to evaluate the botanic composition of secondary vegetation areas. The study was carried out during two years, in the first year, the animal loads used were 0.25, 0.50 and 0.75 animal unit per hectare (AU/ha).The vegetation which animals were evaluated was secondary vegetation of 8 years old. Botanic composition was determined by transects at the beginning of experiment. The two systems used were rotational and alternate grazing with three animals per each load and system.The initial average weights were 175 kg and evaluation were carried out each 56 days. The experimental design used was random totally with factorial arrange of 3X2, the first factor was the animal load and the second was the grazing system. Results indicated changes in botanic composition caused by grazing effect (P≤0.05), furthermore, grazing system and animal loads showed significative statistical differences between treatments and interaction. The best weight gain was 520 g of weight gain average per day detected in 0.50AU/ha with rotational grazing system (P≤0.05). &nbsp

Livestock grazing frequently affects grasshopper populations, but no prior studies have simultaneously examined a wide range of moderate intensity livestock grazing treatments in the Northern Great Plains. Grasshopper densities varied significantly between years, but five moderate grazing treatments, including both rotational and continuous grazing treatments, did not differentially affect grasshopper densities or species composition. Grasshopper populations appear resilient to different types of moderate grazing at this Northern Great Plains mixed-grass prairie site.

Productivity of grassland ecosystems is highly dependent on the availability of nitrogen (N) from the soil and/or biological fixation (BNF) from the atmosphere. However, the high cost of N-fertilizers and the increasing awareness of the need for sustainable nutrient alternative sources have increased the strategic importance of the BNF. Defoliation interferes with plant growth and also with BNF in legumes, since it modifies the leaf area and the availability of energy to plants. In spite of the potential advantages of forage legumes to pastures, current knowledge regarding the effects of grazing management on BNF is scarce. In order to evaluate the effect of grazing management on aerial and root mass, nodulation and BNF in forage peanut (Arachis pintoi cv. Belmonte), two experimental protocols based on the continuous and intermittent (rotational grazing) stocking methods were used. In the continuous stocking protocol, treatments corresponded to four grazing intensities represented by four management heights - 5, 10, 15 and 20 cm. In the intermittent stocking protocol, treatments corresponded to combinations between two pre- (95% and maximum canopy light interception during regrowth – LI95% and LIMax, respectively) and two post-grazing (post-grazing heights equivalent to 40 and 60% of the pre-grazing height) conditions. It was hypothesized that hard grazing, represented by low management heights under continuous stocking or low post-grazing heights under intermittent stocking, causes reduction in root mass and nodulation interfering with the balance between root and aerial, with negative impacts on BNF. Under continuous stocking, greater number of nodules was associated with lower nodule mass and vice-versa throughout the year. Swards managed at 5 and 10 cm had greater root and nodule mass than those managed at 15 and 20 cm. However, greater BNF (%Ndfa and BNF) was recorded on swards managed at 15 and 20 cm relative to those managed at 5 and 10 cm. Under intermittent stocking, the combinations between frequencies and severities of grazing did not affect root mass or nodule number at both pre- and post-grazing conditions. Overall, swards managed with the LIMax target showed greater BNF than those managed with the LI95% target. For swards managed with the same LI target (LI95% or LIMax), hard grazing (40% of the pre-grazing height) resulted in lower %Ndfa and BNF during early and late spring and summer II. For both grazing methods, the range of management targets used did not result in negative impacts on root mass or nodulation. Regardless of grazing method, BNF was determined by aerial biomass, indicating that moderate intensities of grazing would be adequate for optimizing BNF.

Nitrous oxide (N2O) emissions from pastures can vary significantly depending on soil and environmental conditions, nitrogen (N) input, as well as the plant’s ability to take up the N. We tested the hypothesis that legume-based N sources are characterized by significantly lower emission factors than mineral N based dairy systems. Therefore, this study monitored N2O emissions for a minimum of 100 days and up to two growing seasons across a gradient of plant species diversity. Emissions were measured from both, grazed pastures and a controlled application of urine and dung using the static chamber method. About 90% of the accumulated N2O emissions occurred during the first 60–75 days. The average accumulated N2O emissions were 0.11, 0.87, 0.99, and 0.21 kg ha−1 for control, dung, urine patches, and grazed pastures, respectively. The N uptake efficiency at the excreta patch scale was about 70% for both dung and urine. The highest N2O-N emission factor was less than half compared with the IPCC default (0.3 vs. 0.77), suggesting an overestimation of N2O-N emissions from organically managed pastures in temperate climates. Plant diversity showed no significant effect on the N2O emissions. However, functional groups were significant (p &lt, 0.05). We concluded that legume-containing pasture systems without a fertilizer addition generally appear capable of utilizing nitrogen inputs from excreta patches efficiently, resulting in low N2O emissions.

High input dairy farms that are located on sandy soils in northwest Europe are predisposed to substantial nitrate leaching during a surplus of winter precipitation. Leys within integrated crop-livestock systems play an important role in soil fertility, soil C sequestration and soil N mineralization potentials. Therefore, leys are a feasible option that can be utilized to reduce local N losses to the environment, especially following maize grown for silage. We hypothesize that grass-clover leys ensure low nitrate leaching losses even when grazed intensively. The extent to which NO3-leaching occurred across seven different pasture management systems in terms of their sward composition, cutting, grazing, fertilization and combinations thereof was investigated in integrated animal-crop grazing systems over three winter periods (2017/2018, 2018/2019 and 2019/2020). The observed grazed systems were comprised of cut-used-and grazed grass-clover swards (0, 1 and 2 years after establishment following cereals), a catch crop grazed late in the year as well as a cut-used permanent grassland for comparison. Overall, all treatments resulted in nitrate leaching losses that did not exceed the WHO-threshold (25 mg nitrate/L). The highest level of NO3-leaching was observed in the catch crop system and the lowest in cut-used permanent grassland, with NO3-N losses of 19.6 ± 5.3 and 2.1 ± 0.3 kg NO3-N ha−1 year−1 . Annual herbage yields were in the range of 0.9 to 12.4 t DM ha−1 and nitrogen yields varied between 181 ± 51 and 228 ± 66 kg N ha−1 during the study period. The highest herbage-N-yields were observed from the 1-and 2-year-old grass-clover leys. The highest N-field-balance was observed for the grazed leys and the lowest for the cut-used permanent grassland. However, no correlation was found between the highly positive field-N-balance and the amount of NO3-leached. This indicates a high N carry-over from grass-clover swards to the subsequent cash crop unit instead of increasing the risk of groundwater contamination from grazed leys in integrated animal crop-systems and underlines the eco-efficiency of dairy farming based on grazed ley systems.

En el Centro Operativo Experimental de Tacuarendí, durante la campaña 2018/2019, se llevó adelante una experiencia sobre Pastoreo Rotativo Intensivo Inteligente, (PRII). Su objetivo es ajustar la información sobre este sistema de pastoreo en un ambiente de bajos inundables, con ofertas forrajeras diferentes: pastura implantada (Setaria solander) y pastura natural de paja amarilla. EEA Reconquista Fil: Espindola, Carlos María. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Reconquista. Agencia de Extensión Rural Las Toscas; Argentina Fil: Wuthrich, Aldo Facundo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Reconquista. Agencia de Extensión Rural Las Toscas; Argentina Fil: Castro, Cesar German. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Reconquista; Argentina Fil: Benitez, Fernando. Ministerio de la Producción de la Provincia de Santa Fe; Argentina Fil: Yaccuzzi, Milvana. Ministerio de la Producción de la Provincia de Santa Fe; Argentina Fil: Santana, Duilio. Ministerio de la Producción de la Provincia de Santa Fe; Argentina

Nitrous oxide (N2O) emissions from pastures can vary significantly depending on soil and environmental conditions, nitrogen (N) input, as well as the plant’s ability to take up the N. We tested the hypothesis that legume-based N sources are characterized by significantly lower emission factors than mineral N based dairy systems. Therefore, this study monitored N2O emissions for a minimum of 100 days and up to two growing seasons across a gradient of plant species diversity. Emissions were measured from both, grazed pastures and a controlled application of urine and dung using the static chamber method. About 90% of the accumulated N2O emissions occurred during the first 60–75 days. The average accumulated N2O emissions were 0.11, 0.87, 0.99, and 0.21 kg ha−1 for control, dung, urine patches, and grazed pastures, respectively. The N uptake efficiency at the excreta patch scale was about 70% for both dung and urine. The highest N2O-N emission factor was less than half compared with the IPCC default (0.3 vs. 0.77), suggesting an overestimation of N2O-N emissions from organically managed pastures in temperate climates. Plant diversity showed no significant effect on N2O emission. However, functional groups were significant (p < 0.05). We concluded that legume-containing pasture systems without a fertilizer addition generally appear capable of utilizing nitrogen inputs from excreta patches efficiently, resulting in low N2O emissions

There are many different breeds of dairy cattle in the United States. However, research on how well heifers from different breeds develop when grazing pasture alone has not been done in the United States. This data can be very important for dairy producers, since developing heifers is the second largest expense on most dairy farms. In this study, we evaluated the performance of pre-pubertal heifers from four different breeds within a rotational-grazing system in the Intermountain West. For each of two 105-day grazing seasons, 24 dairy heifers from each of four different breeds [Holstein (HO), Jersey (JE), Holstein/Jersey crossbred (HJ), and VikingRed/Holstein/Montbeliarde crossbred (PRO)] were randomly assigned to one of two pasture treatments that consisted of either grass only (MONO) or grass interseeded with the legume birdsfoot trefoil (BFT; MIX). Within our study we looked at the effects of BFT and the differences between breeds for the following: average daily gain (ADG), change in percent mature body weight (CPMBW), fecal egg count (FEC), rumen volatile fatty acids (VFA), and body condition scores (BCS). We saw that BFT significantly increased ADG for all breeds. Heifers which grazed the MIX treatments averaged 0.48 kg of gain/day, whereas heifers on MONO pastures averaged 0.28 kg/day. Overall changes in BCS were significantly affected by both the differences in treatment and breed of the animals. When CPMBW was analyzed, heifers grazing BFT pastures had greater increases as well as there being a difference in breed with JE heifers outperforming other breeds. The different treatments did not cause any significant differences in FEC or total VFA concentrations. Overall, we found that Jerseys were able to gain a higher percentage of their mature body weight and maintain their body condition better, while grazing, than heifers of other breeds. We also determined that grazing BFT can have noticeable positive effects on ADG, BCS, and CPMBW. For dairy producers who graze their animals, it is important for them to realize the benefit of planting BFT in their pastures and the benefit seen in our study of using Jersey heifers, which had better increases in their mature body weight when compared to other breeds. This knowledge can help dairy producers become more efficient and profitable.

High doses of nitrogen (N) fertiliser input on permanent pastures are crucial in terms of N surplus and N losses. Quantitative analyses of the response of plant functional traits (PFT) driving crop growth rate (CGR) under low N input are lacking in frequently defoliated pastures. This study aimed to understand the significance of PFTs for productivity and N uptake in permanent grasslands by measuring dynamics in tiller density (TD), tiller weight (TW), leaf weight ratio (LWR), leaf area index (LAI), specific leaf area (SLA), as well as leaf N content per unit mass (LNCm) and per unit area (LNCa) in perennial ryegrass (Lolium perenne)-dominated pastures, in a simulated rotational grazing approach over two consecutive growing seasons. Annual N application rates were 0, 140 and 280 kg N ha−1. The phenological development of perennial ryegrass was the main driver of CGR, N uptake and most PFTs. The effect of N application rate on PFTs varied during the season. N application rate showed the greatest effect on TD, LAI and, to a lesser extent, on SLA and LNCm. The results of this study highlight the importance of TD and its role in driving CGR and N uptake in frequently defoliated permanent pastures.

Grassland birds, including Bobolinks (Dolichonyx oryzivorus), have experienced steep population declines across their breeding range in North America. Because of these declines, Bobolinks were listed as threatened by the Ontario and Canadian governments. We assessed nest survival across land-cover types and uses to identify pertinent factors important for conservation of this species-at-risk. We analyzed nest survival for 463 Bobolink nests monitored over 6 years from 3 regions across southern and eastern Ontario, Canada. We used RMark to analyze daily survival rate of nests by assessing 53 models that incorporated temporal, local, and landscape variables. Daily survival rate of Bobolink nests was strongly associated with cattle (Bos taurus) stocking rate (cattle-days/ha) and date. Daily survival rate decreased across the nesting season from 0.98 (CI 95% = 0.97-0.99) to 0.92 (CI 95% = 0.87-0.95). Stocking rate was the only important local variable and was negatively associated with daily survival rate, which decreased from 0.96 (CI 95% = 0.96-0.97) to 0.69 (CI 95% = 0.51-0.82) as stocking rate increased from 0 to 243 cattle-days/ha. Landscape variables, including region, percent forest, cropland, and grassland within 2, 5, and 10 km, were not in competitive models. Our results suggest that all field uses we studied have potential for conservation actions because daily survival rate of nests did not vary significantly across late-cut hayfields, fallow fields, restored grasslands, or pastures; however, stocking rate is important in pastures. In grazed pastures where Bobolink conservation is a priority, we recommend keeping stocking rates low (≤ 40 cattle-days/ha) when most Bobolink nests are active, e.g., 21 May (earliest date of incubation) through 30 June (one week after median date of fledging for first nesting attempts) in our study area.

Tesis para obtener el título de Doctor en Ciencias Agropecuarias, de la Universidad de Buenos Aires, en septiembre de 2020. La producción ovina en Patagonia Sur se realiza sobre extensos cuadros de 1000 a más de 5000 ha. En ese contexto, los animales seleccionan libremente los sitios de pastoreo generando a veces áreas sobrepastoreadas y subutilizadas, lo cual afecta la sustentabilidad del pastizal y su uso eficiente. Por ello, se realizó una encuesta a productores con el fin de interpretar como perciben la problemática del pastoreo heterogéneo. Se encontró que los productores detectan la problemática, aunque no dimensionan totalmente el impacto sobre la sustentabilidad ecológica del sistema. Además, presentan diversas limitaciones para la aplicación de tecnologías de remediación. Por otro lado, para abordar la problemática del pastoreo heterogéneo, se buscó identificar los elementos del ambiente que definen los patrones naturales de distribución en sistemas extensivos. Para ello, se determinó un modelo predictivo de la distribución espacial de ovinos, basado en el análisis de 8 cuadros de pastoreo del sur de Santa Cruz. En cada cuadro se equiparon ovinos con collares GPS y se analizó la selección de sitios en relación a variables forrajeras, antrópicas y geomorfológicas. Se encontró que la distribución de los ovinos responde fundamentalmente a la interacción de la altura del terreno con la disponibilidad forrajera y la distancia a alambrados. También, se analizaron patrones de distribución de ovinos bajo diferentes manejos del pastoreo (Holístico vs Continuo) y se evaluó el uso de atractivos (bloques multinutricionales) para mejorar la distribución de los animales en los cuadros. Al contrastar manejos, no se obtuvieron diferencias que expliquen las variaciones en la respuesta productiva, por lo que se considera posible que las eventuales diferencias se manifiesten bajo otras escalas de observación. El uso de los bloques atractivos mejoró la homogeneidad de uso de los cuadros, lo cual significa una importante herramienta de manejo del pastoreo en estos sistemas. Esta tesis aporta información práctica y de base para desarrollar nuevas tecnologías de uso y conservación del pastizal natural. The sheep production in South Patagonia is carried out on extensive paddocks of 1000 to more than 5000 ha. In this context, the animals freely select the grazing sites, sometimes generating overgrazed and underutilized areas, which affects the grassland sustainability and its efficient use. Therefore, a survey was conducted to ranchers in order to interpret how they perceive the problem of heterogeneous grazing. It was found that ranchers detect the problem although they do not fully measure the impact on the ecological sustainability of the system. They also have various limitations for the application of remediation technologies. On the other hand, to address the problem of heterogeneous grazing, we sought to identify the elements of the environment that define the natural patterns of distribution in extensive systems. To do this, a predictive model of the spatial distribution of sheep was determined, based on the analysis of 8 grazing paddocks in southern Santa Cruz. In each paddock, sheep were equipped with GPS collars and site selection was analyzed in relation to forage, anthropic and geomorphological variables. It was found that the distribution of the sheep responds fundamentally to the interaction of the terrain elevation, the forage availability and the distance to fences. Also, sheep distribution patterns were analyzed under different grazing management (Holistic vs Continuous) and the use of attractive (nutritional blocks) was evaluated to improve the distribution of animals in the paddocks. When contrasting management, no differences were obtained that explain the variations in the productive response, so it is considered possible that differences are manifested under other scales of observation. The use of attractive blocks improved the homogeneity of paddock use, which means an important tool for grazing management in these systems. This thesis provides practical and basic information to develop new technologies for the use and conservation of natural grassland. EEA Santa Cruz Fil: Ormaechea, Sebastián Gabriel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina.

Performance of three racial groups of grazing steers supplemented with agroindustrial by-products. The main objective of this research was to evaluate the productive performance of three racial groups of steers, receiving or not supplementation with agro-industry by-products under grazing conditions in the humid Colombian Caribbean. Forty-eight steers: Angus x Brahman (AxB), Simmental x Brahman (SxB) and Romosinuano x Brahman (RxB) with average weight of 274± 13,76 kg and 17 months old were randomly distributed to two types of feed management; with feed supplementation (CSA: 24 animals) and without feed supplementation (SSA: 24 animals) in each breed group, using a complete randomized design (DCA). The supplementation consisted of a mix of rice bran (56.5%), cottonseed (43.5%) and mineralized salt (100 g/steer/day). The highest daily weight gain (GDP) was observed in the animals of the treatments AxB CSA, SxB CSA and RxB CSA (p= 0.001) with 730, 942 and 650 g/day respectively. The GDP of the animals AxB SSA, SxB SSA and RxB SSA, corresponded to 560, 520, and 608 g/animal/day. Regarding body composition by ultrasound measurements, the greater attributes of theribeye area (p=0.0175) were observed for the AxB CSA (43.73 2.54 cm2) y RxB CSA treatments (45,51±2,34 cm2) and for the rump fat thickness (p=0.0229), the RxB CSA treatment (3.97 0.25 mm). The highest projected meat production kg/ha in a year, corresponded to the average for the biotypes of CSA treatment with 1,131.33 kilograms/ha/year, surpassing by 27.5% the production of SSA biotypes treatment of 821.26 kilograms. From the results obtained in this research, the supplementation of grazing steers with by-products of agro-industry becomes a productive activity to increasing GDP and meat production kg/ha, reflecting the potential of this practice as a valid strategy for the development of more efficient and competitive meat production systems for the humid Colombian Caribbean region. El principal objetivo de esta investigación fue evaluar el desempeño productivo de tres grupos raciales de novillos recibiendo o no suplementación con subproductos de la agroindustria en condiciones de pastoreo en el caribe húmedo colombiano. Cuarenta y ocho novillos: Angus x Brahman (AxB), Simmental x Brahman (SXB) y Romosinuano x Brahman (RXB) con peso promedio de 274± 13,76 kg y 17 meses se distribuyeron aleatoriamente en dos tipos de manejo alimenticio; con suplementación alimenticia (CSA: 24 animales) y sin suplementación alimenticia (SSA: 24 animales) en cada grupo racial, usando un diseño completo al azar (DCA). La suplementación consistió de una mezcla de salvado de arroz (56,5%), semilla de algodón (43,5%) y sal mineralizada (100 g/animal/día). Las mayores ganancias diarias de peso (GDP) fueron observadas en los animales de los tratamientos AxB CSA, SxB CSA y RxB CSA (p=0,001) con 730, 942 y 650 g/animal/día, respectivamente. Las GDP de los animales de los tratamientos AxB SSA, SxB SSA y RxB SSA correspondieron a 560, 520, y 608 g/animal/día. En cuanto a las mediciones de composición corporal por ultrasonido, los mayores atributos del área del ojo del lomo, (p=0,0175) lo presentaron los tratamientos AxB CSA (43,73±2,31 cm2) y RxB CSA (45,51±2,34 cm2) y para el espesor de grasa del anca (p=0,0229), el tratamiento RxB CSA (3,97 ± 0,32 mm). La mayor producción de carne, kg/ha proyectada a un año, correspondió al promedio de los biotipos CSA con 1.131,33 kg/ha/año, superando en 27,5% la producción de biotipos SSA de 821,26 kg. A partir de los resultados obtenidos en esta investigación, la suplementación de novillos en pastoreo con subproductos de la agroindustria se convierte en una actividad productiva para incrementar la GDP y producción de carne kg/ha, reflejando el potencial de esta práctica como una estrategia válida para el desarrollo de sistemas de producción de carne más eficientes y competitivos para la región del caribe húmedo colombiano. &nbsp

Optimizacion en el aprovechamiento de los recursos de la finca en el aumento de peso en bovinos mediante el uso de pastoreo rotacional Optimization in the use of farm resources in increasing weight in cattle through the use of rotational grazing Administrador de Empresas Agropecuarias http://www.ustadistancia.edu.co/?page_id=3956 Pregrado

As pastagens são o recurso predominante utilizado nas dietas dos ruminantes e a fonte mais econômica nos sistemas de produção leiteira. Dessa forma, objetivou-se avaliar pastagens formadas por gramíneas do gênero Cynodon (Cv. Tifton 85 e Coastcross) com diferentes alturas de pastejo por meio da produção de forragem, composição morfológica e composição nutricional da massa de forragem em diferentes horizontes de pastejo. O trabalho foi conduzido na área experimental pertencente à Unidade de Ensino e Pesquisa de Bovinocultura de Leite da Universidade Tecnológica Federal do Paraná, Câmpus Dois Vizinhos. As pastagens de Cynodon foram estabelecidas em 2015. Os tratamentos foram compostos por: Tifton 85 com altura de pastejo entre 20 e 25 cm; Tifton 85 com altura de pastejo entre 35 e 40 cm; Coastcross com altura de pastejo entre 20 e 25 cm e Coastcross com altura de pastejo entre 35 e 40 cm, distribuídos em blocos ao acaso com três repetições (piquetes) para cada tratamento. Foram avaliadas a produção total de forragem, a massa de forragem, componentes estruturais, material senescente e espécies invasoras no pré e pós pastejo. Para os componentes nutricionais foram avaliados os percentuais de proteína bruta, fibra em detergente neutro e ácido e digestibilidade “in vitro” da matéria seca. A pastagem de Tifton 85 e o manejo de altura de 35-40 cm apresentaram maior massa de forragem disponível. Os percentuais de material senescente aumentaram com o avanço das estações. As espécies invasoras desenvolveram-se mais no manejo de altura de 35-40 cm e na pastagem de Coastcross. A lotação animal manteve-se constante e a carga animal foi superior para a gramínea Tifton 85 no outono. A análise qualitativa mostrou maior teor de proteína bruta nos estratos 10-25 e 25-40 cm, sofrendo queda com o decorrer das estações. O manejo de altura 35-40 cm elevou os teores de fibra em detergente neutro e ácido e os teores de digestibilidade foram influenciados pelos manejos de altura adotados, sendo superior para as pastagens com altura de pastejo de 20-25 cm. Pastures are the predominant resource used in ruminants’ diet and it is the most economic source in milk production systems. Thus, we aimed to evaluate pastures formed by grass of the Cynodon genus (Cv. Tifton 85 and Coastcross) with different grazing heights through forage production, morphological composition and nutritional composition of forage mass in different grazing horizons. The study was carried out in the experimental area belonging to the Dairy Cattle Teaching and Research Unit at the Federal Technological University of Paraná, Dois Vizinhos Campus. The Cynodon pastures were established in 2015. The treatments were composed of: Tifton 85 with grazing height between 20 and 25 cm; Tifton 85 with grazing height between 35 and 40 cm; Coastcross with grazing height between 20 and 25 cm and Coastcross with grazing height between 35 and 40 cm, randomly distributed in blocks with three repetitions (paddocks) for each treatment. The total forage production, forage mass, structural components, senescent material and invading species in pre and post grazing were evaluated. For the nutritional components, we evaluated the percentages of crude protein, neutral and acid detergent fiber and “in vitro” digestibility of dry mass. The Tifton 85 pasture and managing with 35-40 cm height presented higher available forage mass. The percentages of senescent material increased with the seasons. The invading species developed more in the 35-40 cm height and in the Coastcross pasture. The animal capacity remained constant and the animal load was superior for Tifton 85 pasture in the fall. The qualitative analysis showed higher crude protein content in the 10-25 and 25-40 cm strata, suffering a reduction with the passing of the seasons. The 35-40 cm height increased the neutral and acid detergent fiber contents and the digestibility contents were influenced by the adopted heights, being higher for pastures with grazing height of 20-25 cm.

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.

International audience; Mixed grazing of breeding goats and cattle (goats to cattle ratio: about 50 %, based on metabolic weight) was monitored for 2 years on a rotational pasture with the two species grazing together, then for 5 years with cattle grazing immediately after goats. For both modalities, the level of goat parasite infection was not significantly different from that of the control groups. Nevertheless, the association allowed a slight improvement in kid growth and goat productivity, probably in relation to a better food quality. The response of adult goats to mixed grazing is therefore very different from that previously obtained with kids post-weaning. The question of the relationship between heterogeneity of pastures, knowledge of their environment, grazing behaviour of adult goats and risk of infection with gastrointestinal nematodes requires further investigation.

The objective was to evaluate productive and reproductive performance of beef heifers receiving 0.5% of balanced supplement, as well as the gross margin and direct financial return of the food systems during winter period and to evaluate productive performance, length of stay and number of bits in feeding station, as well as the displacement between each feeding station in heifers under continuous and rotational grazing in Papuã pasture during summer. Experiments were developed on Animal Science Department area at Federal University of Santa Maria. In winter, experimental area used corresponded to 6.4 hectares, divided into eight paddocks of 0.8 hectares each, which constituted the experimental units. Each paddock was divided into five 0.16 ha plots. Field evaluations were carried out from July 21 to November 3, 2016. The feeding systems consisted of beef heifers exclusively on ryegrass pasture (Lolium multiflorum Lam.) and on ryegrass pasture receiving 0.5% of balanced supplement. Forty Angus heifers were used with an initial average age of eight months and 159 ± 28 kg body weight, with three test heifers being allocated to each experimental unit. The grazing method used was rotational, with a variable number of animals and successive periods of occupation and rest. In the summer, experimental area corresponded to 4.8 hectares, with 6 subdivisions of approximately 0.8 hectares each, which constituted the experimental units. The treatments consisted of beef heifers under continuous or rotational grazing managements on Papuã, totalizing five grazing periods, where the first four lasted 16 days with four days of occupation in each plot and twelve days of rest and the last lasted for 24 days with six days of occupation, summing 88 days of use. Twenty-four Angus heifers were used, with an average initial age of 15 months and an initial average weight of 257 kg of body weight (BW), distributed in six paddocks, with four test heifers per paddock. The use of 0.5% balanced supplement promotes a substitutive and additive effect in a combined manner, allowing heifers to reach puberty early. The highest gross margin was seen in the food system using supplements and the best direct financial return in the system exclusively on pasture. The grazing method does not change the forage supply, nor does the leaf:stem ratio, changing the average daily gain. The stocking rate and weight gain per hectare were higher in rotational grazing method. The stay time between stations was not changed by grazing method, whereas steps between stations and number of bits per season were different between grazing methods. O objetivo da pesquisa foi avaliar o desempenho produtivo e desenvolvimento reprodutivo de novilhas de corte recebendo ou não 0,5% do peso vivo por dia de suplemento energético em pastagem de azevém, bem como a margem bruta e retorno financeiro direto desses sistemas alimentares no periodo de inverno. Na estação quente subsequente se avaliou o desempenho produtivo de novilhas sob pastoreio continuo e rotativo em pastagem de papuã. Nessa ocasião também se avaliou o comportamento ingestivo dos animais. Os experimentos foram desenvolvidos em área do Departamento de Zootecnia da Universidade Federal de Santa Maria. No inverno a área experimental utilizada corresponde a 6,4 hectares, dividida em oito piquetes de 0,8 hectares cada, os quais constituíram as unidades experimentais. Cada piquete foi dividido em cinco parcelas de 0,16 ha. As avaliações de campo foram realizadas no período de 21 de julho a 03 de novembro de 2016. Os sistemas alimentares foram constituídos de novilhas de corte exclusivamente em pastagem de azevém (Lolium multiflorum Lam.) e em pastagem de azevém recebendo 0,5% de suplemento energético. Foram utilizadas 40 novilhas da raça Angus com idade média inicial de oito meses e 159 ± 28 kg de PC, sendo alocadas três novilhas-teste em cada unidade experimental. O método de pastoreio utilizado foi o rotativo, com número variável de animais, para ajuste da carga animal. No verão a área experimental corresponde a 4,8 hectares, com 6 subdivisões de 0,8 hectares cada, as quais constituíram as unidades experimentais. Os tratamentos foram constituídos de novilhas de corte sob método de pastoreio continuo ou rotativo em papuã. No total foram cinco períodos de pastoreio, onde os quatro primeiros tiveram duração de 16 dias com quatro dias de ocupação em cada parcela e doze dias de descanso e o último teve duração de 24 dias seis dias de ocupação, totalizando 88 dias de utilização. Foram utilizadas 24 novilhas da raça Angus com idade média inicial de 15 meses e peso médio inicial de 257 kg de peso corporal (PC), distribuídas em seis potreiros, com quatro novilhas teste por potreiro. No período frio o uso de 0,5% de suplemento energético em pasto de azevém promove um efeito substitutivo e aditivo de forma combinada, permitindo que as novilhas atingissem a puberdade precocemente. A maior margem bruta foi verificada no sistema alimentar com uso de suplemento e o melhor retorno financeiro direto no sistema exclusivamente a pasto. No papuã o método de pastoreio não altera a disponibilidade de forragem, bem como a relação folha:colmo, não alterando o ganho médio diário. A taxa de lotação e o ganho de peso por hectare foram superiores no método de pastoreio rotativo. O tempo de permanência entre estações não é alterado pelo método de pastoreio, já os passos entre estações e o número de bocados por estações foram diferentes entre os métodos de pastoreio.

Under the combined effect of stocking rate and grazing season, it is very significant to ascertain whether there is a quantitative relationship between plant community characteristics, chemical composition of forage, and grazing behaviors of Tibetan sheep to better utilize native pasture in the northeast region of the Qinghai&ndash, Tibetan Plateau (QTP). The two consecutive year observation experiments on Tibetan sheep&rsquo, s grazing behavior were conducted to evaluate the above-stated relationships between stocking rates of 8 sheep/ha and 16 sheep/ha stocking rates in the both the warm and cold seasons. The results demonstrated that at 8 sheep/ha or in the warm season, due to better forage quality, Tibetan sheep had higher herbage mass, forage crude protein (CP) concentration, CP intake, dry matter intake (DMI), and interval between feed boluses and total number of steps, as well as lower fiber concentration than that at 16 sheep/ha or in the cold season. Diurnal intake rate and walking velocity while intaking increased as both average daylight ambient temperature and relative humidity rose. Using the CP concentration, acid detergent fiber (ADF) concentration, neutral detergent fiber (NDF) concentration, and forage metabolic energy (ME) to predict grazing behavior yielded the best fit equation for Tibetan sheep. For local herdsmen to sustainably use the alpine meadow, 8 sheep/ha in the warm season should be considered as the better grazing condition for preventing grassland degradation.

Knowledge on sustainable grassland management is available in the large body of literature. However, it is unclear where to look for it, and what is really relevant to the many interrelated challenges of sustainable grassland management. This special issue illustrates options to fill some of those gaps. This editorial introduces the Special Issue entitled “Grassland Management for Sustainable Agroecosystems”. Two review articles deal with (i) concepts for monitoring grassland degradation (by Tiscornia et al. Agronomy 2019, 9, 239) and (ii) impacts of alternative management practices and disturbances (by Wagle and Gowda et al. Agronomy 2018, 8, 300). One paper (by Steiner et al. Agronomy 2019, 9, 699). summarized a series of papers of the special issue. Other topics covered include four main aspects: (I) Landscape features (Ravetto Enri et al. Agronomy 2019, 9, 333), two papers by Northup et al. Agronomy 2019, 9, 329, Northup et al. Agronomy 2019, 9, 281, and Ma et al. Agronomy 2019, 9, 238; (II) climate (Zhou et al. Agronomy 2019, 9, 219, Starks et al. Agronomy 2019, 9, 235, and Moinet et al. Agronomy 2019, 9, 124); (III) soil fertility (Franzluebbers et al. Agronomy 2019, 9, 204, Poblete-Grant et al. Agronomy 2019, 9, 191); and (IV) one on modeling (Puche et al. Agronomy 2019, 9, 183). Two additional papers are from Andueza et al. Agronomy 2019, 9, 273 (on the feed value of barn-dried hay) and Úbeda et al. Agronomy 2019, 9, 340 (on the role of prescribed burns).

Stocking rate adjustment in grazing management is recommended as a management tool to sustain productivity and improve soil health of permanent grassland ecosystems. The aim of this project was to assess the effect of stocking rates under continuous grazing or simple levels of rotational grazing systems on the local environment, when using a moderate or high grazing intensity in the Argentine Patagonia. The parameters investigated were: 1) soil water infiltration and water retention capacity, 2) soil organic matter, N, erosion, and respiration and 3) Plant composition profiles, aboveground net primary production (ANPP), biomass above- and below- ground, physical plant characteristics, and species diversity. In the humid Magellanic grass steppe static rotational grazing was found to increase soil water infiltration rates, N, proportions of forbs and shrubs, root/aerial plant ratio, number of plant species, and proportion of dead plant. Continuous grazing had a greater ANPP, proportion of bare soil, and grasses and graminoids. Under silvopastoral Andean vegetation conditions, rotational grazing resulted in increased root biomass, root/aerial plant ratio, and proportion of forbs compared to continuous grazing, which was found to increase soil organic matter, N, plant length, root depth, aerial plant biomass, soil respiration, proportion of bare soil and dead plants compared to rotational grazing. Intensive grazing negatively influenced soil water, soil and vegetation parameters. The results indicated that adjustment of stocking rate or rotational grazing has a potential to store more biomass than continuous grazing. EEA Santa Cruz Fil: Bjerring, Anna Trier. University of Copenhagen. Faculty of Health and Medical Sciences. Department of Veterinary and Animal Sciences; Dinamarca Fil: Peri, Pablo Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina. Fil: Peri, Pablo Luis. Universidad Nacional de la Patagonia Austral; Argentina. Fil: Peri, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fil: Christiansen, Rodolfo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina. Fil: Christiansen, Rodolfo. Universidad Nacional de la Patagonia Austral; Argentina. Fil: Vargas-Bello-Pérez, Einar. University of Copenhagen. Faculty of Health and Medical Sciences. Department of Veterinary and Animal Sciences; Dinamarca Fil: Hansen, Hanne Helene. University of Copenhagen. Faculty of Health and Medical Sciences. Department of Veterinary and Animal Sciences; Dinamarca

Capítulo de libro. Los pastizales naturales en bosques de ñire (Nothofagus antarctica) ocupan una superficie de 280.290 ha en Patagonia Sur (Santa Cruz y Tierra del Fuego), de los cuales el 70 % tiene uso silvopastoril, es decir que actualmente existen animales pastoreando sus pastizales en alguna época del año con diferentes intensidades. Más del 75 % de los establecimientos con bosques de ñire de Patagonia Sur presentan un acentuado manejo de los potreros en veranadas e invernadas, con alguna participación mínima del manejo rotativo. Sin embargo, existe un escaso manejo silvopastoril integral de los establecimientos. En Patagonia Sur, la producción bovina y mixta (bovino+ovino) tienen la mayor participación en los establecimientos con bosque de ñire, con una carga promedio de 0,65 ± 0,15 equivalentes ovinos/ha y siendo las razas predominantes Corriedale (ovino) y Hereford (bovino). Los beneficios que el productor percibe de los sistemas silvopastoriles en bosques de ñire son la protección que provee al ganado de los fuertes vientos o bajas temperaturas (principalmente en época de parición) y el aporte de forraje de calidad. Además, se determinó que la evaluación de pastizales no era un criterio adoptado masivamente por los productores que en sus estancias tienen ñire, habiéndose observado valores de sólo un 6 % sobre el total de los establecimientos, y donde hasta el 2008, la evaluación de pastizales del sotobosque para ambas provincias era nula (0 %), lo cual puede deberse en gran parte a la falta de métodos precisos y de fácil aplicación. Para garantizar el uso silvopastoril de los ñirantales en el marco de la sustentabilidad es necesario incorporar la evaluación de pastizales dentro del Plan de Manejo del sistema, ya que provee información clave para optimizar la producción ganadera y evitar el deterioro del sistema por sobrepastoreo. En este contexto, en Patagonia Sur recientemente se ha generado un método de evaluación de pastizales que se adapta al ecosistema de ñirantales en Patagonia Sur (Método Ñirantal Sur -San Jorge) como herramienta para estimar la capacidad de carga animal media en sistemas silvopastoriles a nivel predial, lo que determinó que actualmente existan estancias que comenzaron a implementar la evaluación de pastizales del sotobosque. La garantía del uso sustentable de los bosques nativos toma relevancia a partir de la promulgación de la Ley de Presupuestos Mínimos Ambientales para la protección de los bosques nativos, la cual financia parte de los costos del manejo silvopastoril. EEA Santa Cruz Fil: Peri, Pablo Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina. Fil: Peri, Pablo Luis. Universidad Nacional de la Patagonia Austral; Argentina. Fil: Peri, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.

Here in this study we assessed dairy heifers kept in tropical grasslands during spring and summer seasons to observe the effects of two supplementation strategies upon their performance. Sixteen dairy heifers (Holstein 5/8 x Gyr 3/4) with 135.25 kg of body mass were randomly assigned in two supplementation treatments (e.g., mineral salt and protein salt supplement) during spring and summer seasons, divided into two groups of eight animals that represented 4.29 animal unit ha. Initial and final fasted weights (i.e., feed and water withheld for 16h) were obtained before to start and at the end of each grazing cycle (28 days), and then the weight gain (kg animal-1) per grazing cycle was calculated by the difference between final and initial weights. There was no significant effect (P 0,05) entre os tratamentos, estações e interação tratamento vs estação para o GMD que foram 301,12 e 357,13 g dia-1. Observou-se efeito significativo (P

In the past decade soil health has been intensively studied as a science and practiced as a means to help improve the global social, environmental, and economic sustainability. This paper reviews the recent advances of the scientific soil health system. The current understanding and interpretation of soil health from the perspectives of soil functions, processes, and properties is summarized. Multi-tier soil health indicators were selected from relevant soil physical, chemical, and biological parameters. A suite of soil health assessment methods have been developed, such as soil health card, Solvita soil health tests, Haney soil health test, and comprehensive assessment of soil health. An array of soil health management practices have been recommended, including proper land use, crop rotation, cover crops, conservation tillage, soil organic amendment, crop-range-livestock integration, and rotational grazing. Overall, the recommended soil health indicators and assessment methods need further validation and improvement in relevance, scientific validity, practicality, and local adaptation. Continuous research, education, and outreach efforts are warranted to promote localized development, adoption, and implementation of soil health assessment and management.

Rangeland management strategies must be based on robust ecological and economic concepts if they are to be effective and profitable. Thus, the aim of this paper was to examine concepts related to grazing and resting of grassland and associated effects on grassland productivity and energy flow to livestock. Our review and models demonstrate that grassland and livestock productivity is determined by lagged effects of the previous year’s grazing and by grassland maturation, which influence grass growth rates, as well as forage quality. Livestock productivity is also influenced by the scale at which livestock are able to make foraging decisions in time and space, which is restricted by increasing intensity of management (increasing rotation and declining paddock size). Finally, overstocking will override key management initiatives, such as effective recovery periods, leading to rangeland degradation. Thus, in variable climates, stocking rate should be set conservatively to allow easier adaptation of animal numbers to rainfall variability from year to year. We suggest several key concepts that can be used to design and assess grazing management strategies and make suggestions on how to implement these concepts.Keywords: forage quality, grassland productivity, Holistic Planned Grazing™, livestock performance, rotational grazing

Current research evaluates productivity, stocking and nutritional rates of three forage systems with Elephant Grass (EG) + Italian Ryegrass (IR) + Spontaneous Growth Species (SGS), without forage legumes; EG + IR + SGS + Forage Peanut (FP), mixed with FP; and EG + IR + SGS + Red Clover (RC), mixed with RC, in rotational grazing method by lactating cows. IR developed between rows of EG. FP was maintained, whilst RC was sow to respective forage systems. The experimental design was completely randomized, with three treatments and two replication, subdivided into parcels over time. Mean rate for forage yield and average stocking rate were 10.6, 11.6 and 14.4 t ha-1; 3.0, 2.8 and 3.1 animal unit ha-1 day-1, for the respective systems. Levels of crude protein and total digestible nutrients were 17.8, 18.7 and 17.5%; 66.5, 66.8 and 64.8%, for the respective forage systems. The presence of RC results in better and higher forage yield in the mixture, whilst FP results in greater control of SGS. The inclusion of forage legumes in pasture systems provides better nutritional rates.

Rotacijska ispaša u sustavu krava-tele predstavlja pomno planirano pomicanje goveda na pašnjaku tokom cijele godine. Glavni cilj rotacijske ispaše je kvalitetno upravljanje pašnjakom. Takvim sustavom imitira se prirodna migracija goveda te im je osigurano da svaki dan pasu svježu travu. Pašnjak je ograđen električnim pastirom sa pomičnim i nepomičnim električnim ogradama. Važno je osigurati raznolikost livadnih trava te biti upoznat koje su najpovoljnije za zimsku ispašu. Za ovakav tip sustava koriste se mesne i kombinirane pasmine. Pogodne mesne pasmine za uzgoj su: Salers, Limousin, Charolais, Belgijsko plavo govedo, Hereford i Angus. Od kombiniranih pasmina koristi se simentalska pasmina. Životinje se razmnožavaju na pašnjaku prirodnim pripustom i oteljena krava othranjuje vlastito tele. Proizvodnja je ekonomično isplativa jer su smanjeni troškovi mehanizacije, troškovi veterinarskih usluga, hranidbe i mali je utrošak ljudskog rada. Zbog obitavanja u prirodnom okruženju smanjena je prisutnost zaraze i raznih bolesti. Svakodnevnim rotiranjem trava se regenerira i izbjegava se negativan utjecaj na tlo, zemlja se obogaćuje humusom te se dobiju zdrave životinje., Rotational grazing in cow-calf system is well planned movement of cattle on pasture through out the year. Main goal of rotational grazing is quality of pasture management. Rotational grazing imitates natural movements of cattle which ensures fresh slice of pasture every day. Pasture is enclosed with immobile and mobile electric fences. It is important to ensure diversity of grass and to know which grass is suitable for winter grazing. In cow-calf system are used meat breed and combined breed of cattle. Some of the common meat breeds are: Salers, Limousin, Charolais, Belgian blue bull, Hereford and Angus. Combined breed is Simmental. Animals are breeding on pasture and cow takes care of her calf. Production is economical because there are minimum of mechanization costs, veterinary costs, feeding cost and small amount of human work.is needed. Because of the natural environment the presence of the infection and other diseases is reduced. With every day rotations grass is regenerating and the negative impact on soil is reduced, soil is regenerating with humus and cattle are healthy.

La producción ganadera extensiva en la Patagonia Sur se realiza sobre cuadros de pastoreo de gran superficie, escasa receptividad animal y fragilidad ambiental elevada. El manejo histórico del pastoreo, desde fines del siglo XIX, causó la desertificación del paisaje en gran parte del territorio. Diferentes esfuerzos institucionales buscaron mejorar el manejo de los pastizales a través de adecuar la carga animal en los cuadros. No obstante, la heterogeneidad del paisaje dentro de éstos permite que los animales se concentren en los lugares que más prefieren. En este contexto, el desarrollo de recomendaciones técnicas para controlar el pastoreo heterogéneo requiere un conocimiento actualizado de la percepción de los productores frente a esta problemática. Por ello, se llevó adelante una encuesta a 82 productores ganaderos extensivos de Santa Cruz con el objetivo de caracterizar el manejo que realizan en los cuadros de pastoreo, los criterios para su diseño y su visión sobre el problema del pastoreo heterogéneo. Un porcentaje alto de productores (~75%) detecta la problemática, pero sólo 8.3% de ellos aplica más de 2 tecnologías para enfrentarla. En su conjunto, los productores muestran conocer una gran variedad de tecnologías. Sin embargo, los entrevistados señalaron diversas limitantes que determinan que las tecnologías no se consoliden como prácticas de uso común. El sistema extensivo de producción en la Patagonia Sur se sigue llevando adelante mayormente bajo un esquema de mínima intervención del paisaje, tal como en sus inicios. Es posible que sea necesario revisar el sistema de transferencia tecnológica desde las instituciones de investigación y extensión, pero también es imprescindible que el Estado participe diseñando e implementando políticas orientadas a proveer instrumentos idóneos para incentivar, promover, apoyar y monitorear la adopción de tecnología . The extensive livestock system of South Patagonia is carried out on large-scale paddocks, with low animal carrying capacity and high environmental fragility. The historical grazing management, since the end of the 19th century, has caused the desertification of the landscape in a large part of the territory. Different institutional efforts have sought to promote better management of rangelands based on adapting the stocking rate of the paddocks. However, the heterogeneity of the landscape within the paddocks still allows the concentration of animals in the most preferred places. In this context, the development of technical recommendations that allow the control of the heterogeneous grazing, requires an updated knowledge about the perception of the producers facing this problem. For this reason, a survey was carried out to 82 extensive livestock producers in Santa Cruz, seeking to characterize the management they perform in the paddocks, the criteria for their design and how they visualize the problem of heterogeneous grazing. A high percentage of producers (~ 75%) detects the problem, but only 8.3% applies more than 2 technologies to address it. The producers, as a whole, show knowledge of an important variety of technologies. However, different limitations indicated by the interviewees, determine that the technologies are not consolidated as common use practices. The extensive system in South Patagonia continues to be carried out mainly under a scheme of minimal intervention of the landscape, just as in its beginnings. It may be necessary to review the technology transfer system from research and extension institutions. However, the participation of the State is also essential, through the design and implementation of policies that provide suitable instruments to encourage, promote, support and monitor the adoption of technology. EEA Santa Cruz Fil: Ormaechea, Sebastián Gabriel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Manfredi; Argentina. Fil: Peri, Pablo Luis. Instituto Nacional de Tecnología Agropecuaria (INTA), Estación Experimental Agropecuaria Santa Cruz; Argentina. Fil: Peri, Pablo Luis. Universidad Nacional de la Patagonia Austral; Argentina. Fil: Peri, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fil: Cipriotti, Pablo Ariel. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Métodos Cuantitativos y Sistemas de Información; Argentina. Fil: Distel, Roberto Alejandro. Universidad Nacional del Sur. Departamento de Agronomía; Argentina

Conservation actions for the federally and provincially threatened Bobolink (Dolichonyx oryzivorus) in Ontario, Canada are ongoing in agricultural landscapes, including pastures. However, conditions conducive to Bobolink fledging young from breeding territories in rotationally grazed beef cattle (Bos taurus) pastures are not well understood. We tested two management strategies designed to provide habitat where Bobolink could fledge young in rotationally grazed pastures. We conducted (1) a refuge paddock experiment using a crossover design, comparing fledging success when paddocks were ungrazed in one year to when they were grazed in another year; and (2) a light spring grazing experiment. Additionally, we explored associations between fledging of young from territories with cattle stocking rate and date that cattle first entered paddocks. We used spot mapping and nest monitoring to determine if young fledged in 83 Bobolink territories in 2016 and 72 territories in 2017 on six farms in the Ottawa Valley, Ontario. In the refuge paddock experiment, 54% (N = 28) of Bobolink territories fledged young in eight ungrazed paddocks compared to 16% (N = 25) when these paddocks were grazed in another breeding season. In the light spring grazing experiment, 67% (N = 12) of territories fledged young from four paddocks that were grazed with a low stocking rate between 21 May and 03 June 2017 and not again until after 02 July. Additionally, predictions from a logistic regression model indicated that the probability of young fledging from a territory (N = 118) decreased from 0.53 to 0.04 when mid-season stocking rates increased from 0 to 174 cattle-days/ha. Our results illustrate that paddocks on rotationally grazed beef cattle farms that are ungrazed until the Bobolink breeding season is finished or grazed lightly for a brief duration soon after territories are established can provide areas that enable Bobolink to fledge young.

Many livestock farmers are interested in dynamic rotational grazing (DRG), but management criteria can vary among systems. DRG seeks to maximise the utility of grass and is currently a significant topic of discussion. In our study, a specific DRG method, the Herby method, was applied to 23 plots occurring in different contexts. Animals were put out to graze when the grass was at the 3-leaf stage, and they were removed from the pasture before they had grazed down to the leaf sheath, a period of 3 days at most. During each grazing period, we evaluated grass height (using a herbometer), biomass, and nutritional value at the 3-leaf stage. Grass height varied dramatically (especially among seasons). Digestibility and crude protein content were generally good (mean value of 69% and 16%, respectively). These results indicate that the Herby method can be used to provide livestock with very nutritional forage throughout the year., De nombreux éleveurs s'intéressent à la conduite du pâturage tournant dynamique. Cette technique, qui cherche à maximiser la valorisation de l'herbe, fait débat aujourd'hui. En fait, différents critères de gestion du pâturage sont appliqués. Deux d'entre eux sont ici étudiés. Dans 23 parcelles situées dans des contextes différents, une même gestion de pâturage tournant dynamique a été appliquée (méthode Herby) : entrée des animaux au stade 3 feuilles des graminées dominantes, sortie avant de pâturer leur gaine avec un temps de présence de 3 jours maximum. A chaque pâturage, au stade 3 feuilles, ont été évaluées la hauteur d'herbe (à l'herbomètre), la biomasse, la valeur alimentaire de l'herbe. Au stade 3 feuilles, la hauteur d'herbe est très variable (en particulier selon la saison), la digestibilité et la teneur en MAT sont généralement bonnes (en moyenne respectivement de 69% et 16%), sans lien avec la hauteur du couvert. La méthode Herby permet donc d'obtenir une valeur alimentaire du fourrage très satisfaisante au cours de l'année.

The diversification of tropical pastures with legumes (trees) for increased forage and animal productivity has been advocated. Nevertheless, effects on soil quality and belowground biodiversity, and the implications for sustainable intensification remain poorly documented, particularly when cattle grazing is included in the study. We evaluated the impact of forage system diversification with herbaceous and woody legumes on soil properties and soil macrofauna communities and their spatial heterogeneity in a three-year-old field trial in Cauca Valley, Colombia. Three forage-based systems were compared: (i) a conventional monoculture-species grass pasture system of Brachiaria hybrid cv. Cayman (CP); (ii) a mixed pasture system consisting of Brachiaria grass with the leguminous herb Canavalia brasiliensis (LP); and (iii) a silvopastoral system with rows of the legume tree Leucaena diversifolia planted within LP pastures (SPS). The experiment was arranged in a complete randomized block design with three replicates and grazing cattle rotating across blocks. Plots were grazed by three (treatments CP and LP) or four bulls (SPS) aiming to reflect the expected cattle intensification in SPS systems. Physico-chemical soil properties and macrofauna abundance and their spatial heterogeneity as affected by the distance from the tree rows in SPS, were assessed. Herbaceous legumes positively affected the abundance and diversity of soil macrofauna and soil physical properties in LP and the alleys between tree rows in SPS, as compared to CP. In the SPS, the highest soil quality and macrofauna abundance occurred at the edge of the tree lines, while the highest soil compaction and the lowest abundance of soil macrofauna occurred in the tree rows, probably due to the behavioral change of the grazing cattle in combination with the higher stocking rate in SPS. Soil properties in LP and in the alleys between the tree rows of SPS were comparable despite higher stocking rate in SPS. Overall, the SPS and LP systems, proved to be suitable alternatives to CP allowing for sustainable intensification of pastures although careful evaluation of possible trade-offs associated with increased spatial heterogeneity in SPS is recommended to avoid localized soil compaction. Soil macrofauna, particularly functional groups (classified by feeding habits) proved to be a sensitive soil quality indicator in response to contrasting pasture systems.

Soil carbon pools remain a target for sequestering greenhouse gases, but appropriate land management options to achieve such sequestration remain uncertain. Livestock grazing can have profound positive or negative effects on soil carbon. Different models for assessing the influences of grazing are available, but few explicitly account for different management options on soil organic carbon (SOC). Here, I link a previous simple SOC dynamic model (SNAP) to a recent model of episodic grazing and its effects on primary production. The resulting combined model, called SNAPGRAZE, assesses the potential effects of grazing management on SOC across a range of climates with only eight climate, soil, and management input variables. SNAPGRAZE predicts that, at high stocking densities relative to those sustainable under continuous grazing and at higher mean annual temperature and precipitation, short-duration, high stocking density (SDHSD) grazing schemes can enhance forage production and increase stocks of soil organic carbon. Model predictions for current SOC, given a known 50 year grazing history, agrees well with data from nine private ranches in the North American Great Plains. SNAPGRAZE may provide a framework for exploring the consequences of grazing management for forage production and soil carbon dynamics.

Resumen: Las praderas naturalizadas en Magallanes son agro-ecosistemas importantes pero frágiles a las variaciones climáticas y al sobrepastoreo. Desde el año 2013 se introdujo en Magallanes el Pastoreo Holístico como una nueva alternativa tecnológica de manejo intensivo, que tiene como principio, mejorar la salud del pastizal. Considerando esto, es prioritario generar información científica y mantener un seguimiento permanente sobre este tipo de manejo. El objetivo de este trabajo fue analizar los efectos del Pastoreo Holístico sobre la vegetación en términos de estructura y composición. Se compararon tres estancias manejadas bajo Pastoreo Holístico (PH): La Campana, Lago Sofía y Parcela Tamara, con tres áreas bajo Pastoreo Semi-Intensivo (PSI) que incluye rotaciones con descansos cortos, en las estancias: Tres Pasos, Dos Lagunas y Parcela Colonia Isabel Riquelme, todas ecológicamente equivalentes a praderas naturalizadas que derivan de la sustitución de bosques de ñirre (Nothofagus antarctica (G. Forst.) Oerst.) ubicadas en la provincia de Última Esperanza, con un promedio de 389 mm lluvia anual. El estudio se realizó entre 2014-18. La hipótesis fue que el Pastoreo Holístico incrementa la cobertura vegetal, las especies palatables y la diversidad. Para ello se instalaron seis monitores de vegetación y suelos en tres campos con PH y tres de PSI siguiendo la metodología Monitores Ambientales de Regiones Aridas y Semiaridas (MARAS). Los resultados indican que los cambios a través de los años no fueron significativos en cuanto a la cobertura (p>0.8450), pero sí para riqueza de especies (p0,1710). Como conclusión, no se detectó un incremento de cobertura vegetal para el Pastoreo Holístico, pero hubo un reordenamiento de la dominancia de especies, al incrementar la cobertura de especies exóticas palatables, esto puede deberse a que la presión del pastoreo que disminuyó la competencia en el canopeo, favoreciendo a las especies exóticas naturalizadas como el trébol blanco (Trifolium repens) que no podían competir con las malezas invasoras como: Achillea millefolium y Hieracium prealtum. Futuros ensayos deberían considerar evaluar parámetros productivos como disponibilidad forraje, el peso y el estado sanitario animal. Abstract: Naturalized grasslands in Magallanes are important but fragile agro-ecosystems that may change due to climatic variations and overgrazing. Holistic grazing (HG) has been introduced into Magallanes in 2013 as a new, management intensive technological alternative, that in principle would improve the health of grassland. Considering this, it is priority to generate scientific information and malntaln a permanent follow-up on this type of management. The objective of this study was to analyze the effects on vegetation in order to assess whether holistic grazing degrades or improves the floristic structure and composition of naturalized grasslands. We compared three paddocks managed under grazing holistic (HG): La Campana, Lago Sofía and Parcela Tamara, with three equivalent areas under Semi-Intensive grazing (SIG), a traditional management in the area that includes rotations with short rests: Tres Pasos, Dos Lagos and Parcela Colonia Isabel Riquelme. All areas were ecologically equivalent and derived from substitution of ñirre forests (Nothofagus antárctica (G. Forst.) Oerst.), and located in the province of Última Esperanza, with 389 mm annual ralnfall. The study was conducted between 2014-18, with an average ralnfall of 372 mm which is within normal for that area. The hypothesis was that the HG would increase the vegetation cover, palatable species cover and diversity. Vegetation and soil monitors were installed in three fields with HG and three SIG following the MARAS methodology. The results indicate that changes over the years were not significant in terms of cover (p>0.8450), but significant differences were observed in species richness (P < 0.0001), with a greater number of species for the SIG. Significant differences were also detected in cover of exotic species (p0.1710). In conclusion, plant cover increase was not detected for HG, but species dominance was rearranged, as palatable, exotic species, increased under HG. This is perhaps because grazing pressure decreased competition in the canopy, favoring naturalized exotic species such as white clover (Trifolium repens) that could not compete with invasive weeds like Achillea millefolium and Hieracium prealtum under SIG. Future trials should consider evaluating productive parameters such as forage avallability, weight and animal health status.

Simple Summary In grazing systems of temperate climate zones dairy cows are often fed with a silage- and concentrate-based diet during winter and are gradually introduced to a pasture-based diet in spring. This housing and feeding change involves many complex nutritional, behavioral, and metabolic adaptions, likely connected with alterations in energy metabolism. In a previous trial, feeding low amounts of concentrate during full-time grazing had not prevented energy shortage during the first weeks on a pasture system. Because of this, further research was needed to determine whether a higher concentrate supply during full-time grazing would have attenuated that energy deficit. In this experiment we were able to show that the transition period is connected with a higher activity due to walking and grazing, associated with changes in red blood cell count. Further parameters like lipomobilization, decreasing milk production, and loss in bodyweight confirm the alterations in energy metabolism. In summary, the present study shows the changes and its impact on the animals during transition to full-time grazing. Abstract In spring, the transition from a total mixed ration (TMR) to pasture requires metabolic adaptions for the cow. It had been shown that supply of low amounts of concentrate after transition to full-time grazing caused energy deficits, resulting in a lower milking performance and changes in a variety of variables indicative for energy metabolism. The present study aimed to investigate how a moderate concentrate supply (4.5 kg dry matter cow/day) after transition to pasture influences health and production indicators. Over a 12-week trial period dairy cows were observed during transition from confinement to pasture (pasture group: PG) and compared to cows fed TMR indoors (confinement group: CG). On average, the PG consumed less feed and energy than the CG and mobilized body reserves, which is mirrored in a decrease of body condition and various fat depots. These effects were paralleled by elevated serum concentrations of non-esterified fatty acids and ketone bodies as well as an increase in liver fat content. The physical activity (elevated walking, eating, decreasing rumination time) of the PG was significantly higher than that of the CG, which intensified the energy deficiency and resulted in a lower milk yield. In conclusion, the moderate concentrate supply was insufficient to counterbalance the lower energy intake from pasture during transition.

RESUMO: O sistema de pastejo rotacionado irrigado é uma alternativa para a ovinocultura do semiárido. No entanto, a maior limitante para sua implementação são as dificuldades para controlar as parasitoses gastrintestinais. Neste trabalho objetivou-se determinar medidas de manejo para o controle das helmintoses gastrintestinais de ovinos em pastejo rotacionado irrigado e fazer a análise econômica do sistema. O experimento foi realizado em uma fazenda no Munícipio de Belém do São Francisco, Pernambuco, no período de abril de 2013 a setembro de 2014, em um rebanho de 646 a 859 ovinos mestiços da raça Dopper com Santa Inês, criados em uma área de 12 ha de pastagem de capim coast cross (Cynodon dactylon) dividida em 24 piquetes. Para o pastejo os ovinos foram divididos em dois grupos, um de ovelhas paridas e outro de ovelhas secas e borregas de mais de dois meses, que pastejavam três dias em cada piquete. Os piquetes tinham 36 dias de descanso. Foi feito teste de resistência aos anti-helmínticos no início de experimento e anualmente, que resultou na mudança anual do produto utilizado. No segundo ano, para as coletas de fezes e para o tratamento anti-helmíntico seletivo, as ovelhas paridas e as ovelhas secas foram divididas em dois subgrupos cada: paridas gordas, paridas magras, secas magras e secas gordas. Todos os meses coletavam-se fezes de 10% dos ovinos de cada subgrupo para fazer OPG e coprocultura. Cada grupo era tratado quando apresentavam média de mais de que 1000 OPG. Coletaram-se amostras de capim a cada dois meses para fazer a contagem e identificação de larvas do pasto. Durante os 18 meses de estudo foram tratados individualmente aproximadamente 3797 ovinos, equivalente a 6,49 tratamentos por ovino (3,97 em 2013 e 2,52 em 2014). O helminto mais prevalente nas coproculturas (50-85%) e no pasto (83,2%) foi Haemonchus contortus. Os menores números de larvas infectantes no pasto (94 a 111 larvas L3/ kg MS) ocorreram nos dias 35 e 2 a 8 de pastejo e os maiores números entre os dias 17 a 20 (374 a 761 L3/kg MS). A produção de carne da fazenda foi 1023 kg por hectare e a rentabilidade de 3,31%. Conclui-se que o pastoreio dos potreiros por três dias, com um descanso de 36 dias, com a utilização de tratamento seletivo, permite controlar as helmintoses gastrintestinais em sistemas de pastoreio rotacional irrigado. No entanto, é necessário realizar testes de resistência dos parasitas aos anti-helmínticos anualmente para contornar esse problema. ABSTRACT: The irrigated rotational grazing system is an alternative for sheep farming in the Brazilian semi-arid region. However, the mean limitation for its implementation is the difficulty to control gastrointestinal nematodes. The objective of this research was to determine management measures for the control of the gastrointestinal nematodes of sheep in irrigated rotational grazing and to perform the economic analysis of the system. The experiment was carried out on a farm in the Municipality of Belém do São Francisco, Pernambuco, from April 2013 to September 2014, in a herd of 646 to 859 crossbred Dorper x Santa Inês sheep, reared in an area of 12 hectares with coast cross (Cynodon dactylon) pastures divided into 24 paddocks. For grazing, the sheep were divided into two groups: one of lactating ewes and their lambs, and the other with non-lactating ewes and ewe hoggets older than two months. Both groups grazed three days in each paddock and each paddock lasted 36 days without being grazed. Antihelminth Fecal Egg Count Reduction Tests were performed at the beginning of the experiment and annually, resulting in the annual change of the drug used. In the second year, for fecal collections and for selective anthelmintic treatment, the ewes and the non-lactating sheep were divided into two subgroups each: fat and thin lactating ewes, and fat and thin non-lactating ewes. Each month, feces of 10% of the sheep of each subgroup were collected for egg counts and larval culture. Treatments were performed when the mean fecal egg counts were greater than 1000/g. Samples of grass were collected every two months to count and identify grass free-living Trichostrongylidae larvae. During the 18 months of study, approximately 3797 individual anthelmintic treatments were performed, equivalent to 6.49 treatments per sheep (3.97 in 2013 and 2.52 in 2014). The most prevalent helminth in coprocultures (50%-85%) and pasture (83.2%) was Haemonchus contortus. The lowest numbers of infective larvae in the pasture (94 to 111 larvae L3/kg DM) occurred on days 35 and 2 to 8 of grazing. The highest numbers occurred between days 17 to 20 (374 to 761 L3/kg DM). The meat production of the farm was 1023 kg per hectare and the profitability was 3.31%. It is concluded that grazing the paddocks for 3 days, with a rest of 36 days and using selective treatments, allows the control of gastrointestinal nematodes in irrigated rotational grazing systems. However, annual resistance tests are necessary to mitigate resistance of parasites to anti-helminths.