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Journal articles on the topic 'Pasture sampling'
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1
BOYARD, C., J. BARNOUIN, P. GASQUI, and G. VOURC'H. "Local environmental factors characterizing Ixodes ricinus nymph abundance in grazed permanent pastures for cattle." Parasitology 134, no. 7 (February 12, 2007): 987–94. http://dx.doi.org/10.1017/s0031182007002351.
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SUMMARYAlthough Ixodes ricinus ticks are mainly associated with woodland, they are also present in open habitat such as pastures. The distribution of nymphal I. ricinus was monitored by drag sampling the vegetation in May–June 2003 on 61 grazed permanent pastures for cattle located in central France. After selecting explanatory variables from among a set of 155, tick abundance was modelled on the perimeter of the pasture using a negative binomial model that took into account data overdispersion. An abundant tree layer at the perimeter of the pasture associated with a high humidity before sampling greatly enhanced the average number of captured I. ricinus nymphs. The presence of apple or cherry trees around the pasture perimeter, the presence of trees or bushes at the pasture edge, woodland around the pasture and a high number of I. ricinus nymphs in the nearest woodland to the pasture were also favourable to nymph abundance in the pasture. The study highlighted that woodland vegetation associated with humidity and the presence of attractive foraging areas for tick hosts around the pasture played a key role in the abundance of I. ricinus. Finally, the results raised the question of whether and how transfer of ticks between woodland and grazed pastures occurs.
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McCaughey, W. P., K. Wittenberg, and D. Corrigan. "Impact of pasture type on methane production by lactating beef cows." Canadian Journal of Animal Science 79, no. 2 (June 1, 1999): 221–26. http://dx.doi.org/10.4141/a98-107.
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In order to determine the quantity of methane (CH4) produced by lactating beef cows on pasture, 16 Hereford–Simmental first-calf heifers with a mean weight of 511.2 ± 5.8 kg were randomly selected from a larger group of cows (n = 60) on a grazing management experiment and used to evaluate the effects of pasture type on ruminal CH4 production using the sulfur hexafluoride (SF6) tracer-gas technique. Pasture treatments consisted of two pasture types, alfalfa-grass [78% alfalfa (Medicago sativa L.) – 22% meadow bromegrass (Bromus biebersteinii Roem and Schult.)] or 100% meadow bromegrass at each of two fertility levels (either unfertilized or soil test recommended fertilizer levels) with two replications of each pasture treatment (8 pastures). Cows were managed using a "put and take" stocking system to leave equal residual herbage mass on all treatments following the grazing period in each paddock. During the 69-d grazing season, two cows from each pasture were sampled to determine daily forage intake and CH4 production on four occasions. The chemical composition of diets differed between pasture types and sampling periods. Dry matter intake was greater for cows grazing alfalfa–grass pastures than for cows grazing grass-only pastures (11.4 vs. 9.7 kg DM d−1. P < 0.018). However, methane production was greater for cows grazing alfalfa–grass pastures than for cows grazing grass-only pastures (373.8 vs. 411.0 L CH4 d−1. P < 0.008). Consequently, energy lost through eructation of CH4 was less for cows grazing alfalfa–grass pastures than it was for cows grazing grass-only pastures (7.1 vs. 9.5% of GEI; P < 0.001). Key words: Methane, cattle, environment, digestion efficiency, pasture, forage
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Hutchinson, K. J., D. R. Scobie, J. Beautrais, A. D. Mackay, G. M. Rennie, R. A. Moss, and R. A. Dynes. "A protocol for sampling pastures in hill country." Journal of New Zealand Grasslands 78 (January 1, 2016): 203–9. http://dx.doi.org/10.33584/jnzg.2016.78.511.
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To develop a protocol to guide pasture sampling for estimation of paddock pasture mass in hill country, a range of pasture sampling strategies, including random sampling, transects and stratification based on slope and aspect, were evaluated using simulations in a Geographical Information Systems computer environment. The accuracy and efficiency of each strategy was tested by sampling data obtained from intensive field measurements across several farms, regions and seasons. The number of measurements required to obtain an accurate estimate was related to the overall pasture mass and the topographic complexity of a paddock, with more variable paddocks requiring more samples. Random sampling from average slopes provided the best balance between simplicity and reliability. A draft protocol was developed from the simulations, in the form of a decision support tool, where visual determination of the topographic complexity of the paddock, along with the required accuracy, were used to guide the number of measurements recommended. The protocol was field tested and evaluated by groups of users for efficacy and ease of use. This sampling protocol will offer farmers, consultants and researchers an efficient, reliable and simple way to determine pasture mass in New Zealand hill country settings. Keywords: hill country, feed budgeting, protocol pasture mass, slope
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Heard, J. W., S. A. Francis, and P. T. Doyle. "Nutritive characteristics of annual species in irrigated pasture in northern Victoria." Australian Journal of Experimental Agriculture 46, no. 8 (2006): 1015. http://dx.doi.org/10.1071/ea04268.
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We examined changes in estimated metabolisable energy (ME), crude protein (CP) and neutral detergent fibre (NDF) concentrations of irrigated annual pastures through winter and spring in 2002. The types of pastures sampled were ‘high’ subterranean clover (HS, at least 800 g/kg DM clover), ‘low’ subterranean clover (LS, about 400 g/kg DM clover) and ‘low’ Persian clover (LP, about 500 g/kg DM clover). Estimates were also made of selection differentials, namely the nutrient concentration in the pasture fraction likely to be consumed expressed as a proportion of the nutrient concentration in the whole sward to ground level. The ME concentrations in all pasture types increased from May to August, after which concentrations in LS and LP declined, while the ME concentrations in HS declined after September. Low Persian pasture was significantly (P<0.001) higher in ME than the subterranean clover pastures except in September. There was a significant quadratic relationship between ME and time in months and this relationship differed significantly between the 3 pasture treatments. There was a significant (P<0.001) linear decline in CP concentration through the sampling period. The rate of decline in CP concentration was greatest for HS and lowest for LP pastures. Neutral detergent fibre concentrations declined gradually until August and then increased in all pastures. High subterranean clover pastures were lower (P<0.05) than LS pastures in all months. Low Persian clover pastures were higher in NDF than HS pastures, but lower than LS pastures in most months.There were small but significant differences in selection differentials for estimated ME between months when pastures were cut to 4 cm. Selection differentials for ME were between 1.01 and 1.13 across pasture types. Crude protein selection differentials were higher than for ME and varied between 1.11 and 1.46. There were small significant differences in selection differentials between months for NDF (0.74–0.96). Calculated selection differentials at different cut heights indicated that a nutrient gradient existed throughout the annual pasture sward. Pastures cut at high (>8 cm) cut heights had higher ME and CP and lower NDF, than pastures cut to 4 cm. Differences in selection differentials at different cut heights were apparent between pasture types.
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McFarlane, JD, GJ Judson, and J. Gouzos. "Copper deficiency in ruminants in the South East of South Australia." Australian Journal of Experimental Agriculture 30, no. 2 (1990): 187. http://dx.doi.org/10.1071/ea9900187.
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Pasture development in the South East of South Australia has depended upon trace element enriched fertiliser applications. Despite the wide usage of copper-enriched fertilisers, copper deficiency is still evident in livestock at pasture, particularly cattle. Serum collected from cows and heifers during the systematic sampling program of the Brucellosis and Tuberculosis Eradication Scheme was analysed for copper. Of the 3611 pooled herd samples analysed, approximately 9% had low serum copper concentrations (<7 �mol/L). Distribution of those herds identified to be at risk of copper deficiency appeared to be random, apart from areas of high risk on peat soils and the coastal fringe of calcareous sands. Analysis of pasture samples collected from paddocks with cattle having low serum copper concentrations showed that low serum copper was usually associated with raised molybdenum rather than low copper concentrations in pasture. In some instances, moderate concentrations of molybdenum and sulfur in pasture and soil ingestion associated with high iron concentrations may combine to cause hypocupraemia, especially when livestock graze stubbles and subterranean clover pastures in summer-autumn and short pastures in winter. Only 6% of pasture samples had less than 4 mg Cu/kg DM, a concentration which indicates possible copper deficiency in subterranean clover or strawberry clover.
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Serrano, João, Shakib Shahidian, Francisco Moral, Fernando Carvajal-Ramirez, and José Marques da Silva. "Estimation of Productivity in Dryland Mediterranean Pastures: Long-Term Field Tests to Calibration and Validation of the Grassmaster II Probe." AgriEngineering 2, no. 2 (April 25, 2020): 240–55. http://dx.doi.org/10.3390/agriengineering2020015.
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The estimation of pasture productivity is of great interest for the management of animal grazing. The standard method of assessing pasture mass requires great effort and expense to collect enough samples to accurately represent a pasture. This work presents the results of a long-term study to calibrate a Grassmaster II capacitance probe to estimate pasture productivity in two phases: (i) the calibration phase (2007–2018), which included measurements in 1411 sampling points in three parcels; and (ii) the validation phase (2019), which included measurements in 216 sampling points in eight parcels. A regression analysis was performed between the capacitance (CMR) measured by the probe and values of pasture green matter and dry matter (respectively, GM and DM, in kg ha−1). The results showed significant correlations between GM and CMR and between DM and CMR, especially in the early stages of pasture growth cycle. The analysis of the data grouped by classes of pasture moisture content (PMC) shows higher correlation coefficients for PMC content >80% (r = 0.775; p < 0.01; RMSE = 4806 kg ha−1 and CVRMSE = 28.1% for GM; r = 0.750; p < 0.01; RMSE = 763 kg ha−1 and CVRMSE = 29.7% for DM), with a clear tendency for the accuracy to decrease when the pasture vegetative cycle advances and, consequently, the PMC decreases. The validation of calibration equations when PMC > 80% showed a good approximation between GM or DM measured and GM or DM predicted (r = 0.959; p < 0.01; RMSE = 3191 kg ha−1; CVRMSE = 23.6% for GM; r = 0.953; p <0.01; RMSE = 647 kg ha−1 and CVRMSE = 27.3% for DM). It can be concluded that (i) the capacitance probe is an expedient tool that can enable the farm manager to estimate pasture productivity with acceptable accuracy and support the decision-making process in the management of dryland pastures; (ii) the more favorable period for the use of this probe in dryland pastures in a Mediterranean climate, such as the Portuguese Alentejo, coincides with the end of winter and beginning of spring (February–March), corresponding to PMC > 80%.
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McNeill, M. R., and C. Van_Koten. "Weevils in pasture a comparison of sampling techniques." New Zealand Plant Protection 64 (January 8, 2011): 284. http://dx.doi.org/10.30843/nzpp.2011.64.5987.
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This study compared four methods to quantitatively sample adult Listronotus bonariensis and Sitona lepidus (both Coleoptera Curculionidae) in dairy pasture with a view of determining an appropriate sampling method for accurate population estimation in terms of weevils/m2 Collections were made by one of three vacuum methods a vacuum cleaner to take 12 02 m2 quadrats a Vortis (24 16 cm diameter 002 m2) or blowervac (30 m ca 11 cm diameter 327 m2) to suck the weevils from the soil surface; or by taking turf cores (48 10 cm diameter 000785 m2) with extraction of weevils using a Berlesse funnel The sampling was carried out on three occasions and the four methods compared for each occasion Overall for both weevil species coring or the vacuum cleaner generally indicated significantly higher densities compared to the Vortis or blower vac and are concluded to be the most accurate methods for measuring adult density However the blowervac is a convenient tool for mass collection of weevils and parasitoids while the Vortis is useful for monitoring more fragile insects such as Hymenoptera
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McCown∗, S., J. Ringler, K. Watson, B. Cassill, J. Stine, and L. Lawrence. "Sampling Factors Affecting Carbohydrate Measurements in Pasture Grasses." Journal of Equine Veterinary Science 29, no. 5 (May 2009): 410–11. http://dx.doi.org/10.1016/j.jevs.2009.04.109.
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Mudge, P. L., L. A. Schipper, W. T. Baisden, A. Ghani, and R. W. Lewis. "Changes in soil C, N and δ15N along three forest–pasture chronosequences in New Zealand." Soil Research 52, no. 1 (2014): 27. http://dx.doi.org/10.1071/sr13183.
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Changes in total soil carbon (C), nitrogen (N) and natural-abundance N isotopes (δ15N) were measured along three forest-to-pasture chronosequences on pumice soils in the Central North Island of New Zealand. On each of the three chronosequences, exotic pine forests had been converted to intensive dairy pastures 2–11 years before sampling and samples were also taken from remaining pine forests and long-term pastures (40–80 years old). The primary objective of the study was to test the hypothesis that surface-soil δ15N would increase over time following conversion of forest to pasture, due to greater N inputs and isotope-fractionating N losses (e.g. ammonia volatilisation) in pasture systems. Results supported our hypothesis, with linear regression revealing a significant (P < 0.001) positive correlation between log-transformed pasture age (log10[pasture age + 1]) and surface-soil δ15N. There was also a positive correlation (P < 0.001) between pasture age and total soil C and N, and a negative correlation of pasture age with C : N ratio. Surface-soil δ15N was also positively correlated (P < 0.001) with total soil N, and negatively correlated with C : N ratio when C : N was <13.6. These results suggested that as soils became more N-‘saturated’, isotope-fractionating N loss processes increased. Surface-soil δ15N in the pine forests was significantly less than subsoil δ15N, but there was no significant difference between the surface and subsoil in the long-term pastures, due to 15N enrichment of the surface soil. The difference in δ15N between the surface soil and subsoil may be a useful indicator of past land management, in addition to absolute δ15N values of surface soils.
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Batson, M.-G. "Effect of pasture renovation on the size and composition of the germinable fraction of the seed pool beneath bent grass (Agrostis castellana) pastures in southern Victoria." Australian Journal of Agricultural Research 50, no. 1 (1999): 87. http://dx.doi.org/10.1071/a98026.
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This paper investigated the potential for propagation of grass weeds from seed by measuring changes in the size and composition of the germinable fraction of the seed pool beneath 4 bent grass (Agrostis castellana) pastures in southern Victoria during renovation. Soil samples, for the estimation of the seed pool by seedling emergence in the glasshouse, were taken from a control and a renovated pasture on 3 occasions during renovation at each of the 4 sites. The depth distribution of seeds in the top 0–100 mm was assessed by dividing collected soil samples into depths of 0–30 mm and 30–100 mm. The total germinable seed pool (0–30 mm) ranged from 17 620 to 83 540 seedlings/m2, as affected by the time of sampling. There were seedlings from 14 grass genera (12% contribution to the total seed pool), Juncus (60%), 4 leguminous genera (17%), and 22 other dicotyledonous genera (12%). The percentage change in the number of germinated seeds of grasses and dicotyledons between the first and second sampling was negative ( –7·3% to –31·4%) beneath renovated pasture, as opposed to a positive change (29·0–174·4%) beneath undisturbed pasture; this was attributed to the prevention of seeding due to the cultivation of the pasture associated with renovation. The percentage change in the number of germinated seeds of grasses and dicotyledons did not differ significantly between renovated and undisturbed pasture between the second and third sampling, which suggested that no more seed germinated in response to renovation. Re-distribution of germinable seed to lower depths (30–100 mm) with renovation was apparent for grasses and other dicotyledons, and would depress successful emergence of these seedlings. Renovation prevented re-seeding of weeds and buried surface seed, but did not significantly stimulate additional seed to germinate the following autumn after renovation. Weed seeds were still present in the soil seed pool after renovation, which indicated that these species could potentially germinate and establish in new pastures.
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Reed, K. F. M., J. R. Walsh, P. A. Cross, N. M. McFarlane, and M. A. Sprague. "Ryegrass endophyte (Neotyphodium lolii) alkaloids and mineral concentrations in perennial ryegrass (Lolium perenne) from southwest Victorian pasture." Australian Journal of Experimental Agriculture 44, no. 12 (2004): 1185. http://dx.doi.org/10.1071/ea03242.
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On all of 120 farms in south-west Victoria that were selected at random and sampled during autumn and winter over 2 years, perennial ryegrass was present in the pasture and tested positive for the presence of the naturally occurring ryegrass endophyte, Neotyphodium lolii (mean frequency 78%). Ryegrass staggers were reported on 33% (1999) and 43% (2000) of the surveyed farms. Clinically significant concentrations of lolitrem B were detected in perennial ryegrass samples with concentrations in the range 0–4.44 mg/kg. Concentration exceeded 1.8 mg/kg in 37% of pastures indicating an inherent, widespread problem for livestock farmers. Concentration was independent of endophyte frequency, pasture age, pasture height, annual rainfall and origin of sown cultivar. Ergovaline was detected in most of the perennial ryegrass samples with concentrations up to 3.90 mg/kg. In 1999, the mean concentration of ergovaline was 0.76 (± 0.70) mg/kg with 33% of pastures having a level >0.4 mg/kg, the level associated with heat stress in cattle. In 2000, sampling was carried out later in the year than for the 1999 survey and the mean concentration of ergovaline was 0.12 (± 0.10) mg/kg; 3% of samples exceeded 0.4 mg/kg. The mean concentration of peramine was 13.7 (± 6.6) mg/kg in the 1999 survey and 4.2 (± 5.1) mg/kg in the 2000 survey. Mineral analysis indicated that perennial ryegrass nutrition was inadequate with regard to phosphorous on 17% of the dairy pastures and on 37% of the sheep/beef pastures. Potassium was deficient in perennial ryegrass on 5 and 37% of dairy and sheep/beef pastures respectively. For perennial ryegrass in sheep/beef pastures, 25% were deficient in sulphur. For lactating cattle having only perennial ryegrass as a food source, phosphorous and copper concentrations in the grass were inadequate on 80% of the pastures. Calcium, zinc, magnesium, potassium and sulphur concentrations in perennial ryegrass were also inadequate on some pastures. However, with 1 exception, the ratio [K/(Ca+Mg) expressed as equivalents] was less than 2.2, the level associated with the development of hypomagnesemia. Hypomagnesemia (grass tetany) was therefore unlikely to be a major cause of the staggers syndrome. Lolitrem B was negatively correlated with grass potassium concentration (P<0.001). Ergovaline was negatively correlated with date of sampling (P<0.001). Peramine concentration was positively correlated with endophyte frequency, the potassium and sodium concentrations in perennial ryegrass and negatively correlated with date of sampling. The need for research on the economic impact and management of pasture contaminated with ryegrass endophyte toxins is discussed.
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Corazza, Edemar Joaquim, Michel Brossard, Takashi MuraokaI, and Maurício Antonio Coelho Filho. "Spatial variability of soil phosphorus of a low productivity Brachiaria brizantha pasture." Scientia Agricola 60, no. 3 (2003): 559–64. http://dx.doi.org/10.1590/s0103-90162003000300022.
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Studies on soil phosphorus (P) of low productivity cultivated pastures in Cerrado (Brazilian Savanna) areas and surveys on other possible problems related to P are scarce. The spatial variability of soil phosphorus content of a Rhodic Ferralsol was studied in a low productivity pasture of Brachiaria brizantha (BB) grown for 10 years, without fertilizer application, in an experimental area at Planaltina (GO), Brazil. Soil samplings were performed on a regular grid of 10 by 10 meters, with 98 sampling points before (between tussocks and under tussocks) and after the establishment of the experiment (after fertilizing). On the same grid, forage plants were collected and separated into fractions for N and P content analyses. Soil available phosphate was determined by the resin method (Pr) and complemented by the 32P isotopic exchange kinetics analysis. Descriptive statistical and geostatistical analyses were utilized to describe the spatial variability. The Pr content on soil samples under tussocks presented mean and median values 45% larger than in soil samples taken between tussocks. The higher variation is probably related to the greater concentration of BB roots, soil organic matter content and soil P recycled through the plants tussocks. The spatial variability of Pr in this soil was high especially after fertilizer application. This variable did not present spatial dependence for the regular 10 m sampling. The generated knowledge on P variability of soils under low productivity cultivated pastures revealed problems related to the sampling methodology traditionally utilized and to P application.
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Vasco, Ana Caroline Cerqueira de Melo, Ana Margarita Arias-Esquivel, Emma Seals, Fabiane Quevedo da Rosa, Marcelo Wallau, Lori K. Warren, and Carissa Wickens. "111 Grazing behavior of horses managed on legume-grass mixed pastures." Journal of Animal Science 98, Supplement_4 (November 3, 2020): 89. http://dx.doi.org/10.1093/jas/skaa278.162.
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Abstract Intercropping legume into grass pastures improves pasture quality and decreases the need for nitrogen (N) fertilizer, while providing a more heterogenic grazing environment. This study aimed to evaluate the effect of rhizoma peanut (RP, Arachis glabrata) intercropped into bahiagrass (Paspalum notatum) pasture on horse grazing performance. Unfertilized bahiagrass (UNF) with no N fertilizer, bahiagrass with 120 kg N ha-1 (FER), and bahiagrass with RP and 30 kg N ha-1 (RP) pastures were evaluated using twelve mature Quarter Horses continuously stocked for 84 days in a randomized block design with two blocks. Grazing, activity and leisure behaviors were recorded every 10 minutes for 24 hours on day 35 and 70 using scan sampling. Chew (CR, chew/min) and bite (BR, bite/min) rates were counted for five consecutive 1-min intervals on days 36 and 71. Data were analyzed using a repeated measure mixed model ANOVA. Pasture did not affect (P > 0.05) total time spent on grazing (13.57 ± 1.81 h, mean ± SD), leisure (9.64 ± 1.64 h), and activity (0.79 ± 0.60 h). Pasture x time of day interaction (P < 0.05) was significant for grazing, leisure and activity. Horses grazing FER spent more time grazing between 1100 and 1700 h, whereas horses grazing RP spent more time grazing between 2300 and 500 h when compared to horses grazing FER. Horses grazing FER spent more time in leisure between 2300 and 700 h. No day or pasture effects were observed for BR (30.8 ± 6.3 bites/min, mean ± SD), but a pasture x day interaction was observed for CR. On day 36, CR of horses grazing FER was similar to RP (50.8 and 53.8 chews/min), but lower than RP on day 71 (41.4 and 61.3 chews/min). Intercropping RP into bahiagrass pastures does not affect total grazing, leisure and activity time of horses.
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Kariuki, Solomon K., Hailin Zhang, Jackie L. Schroder, Travis Hanks, M. Payton, and Tracy Morris. "Spatial Variability and Soil Sampling in a Grazed Pasture." Communications in Soil Science and Plant Analysis 40, no. 9-10 (May 2009): 1674–87. http://dx.doi.org/10.1080/00103620902832089.
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Lodge, G. M., K. L. King, and S. Harden. "Effects of pasture treatments on detached pasture litter mass, quality, litter loss, decomposition rates, and residence time in northern New South Wales." Australian Journal of Agricultural Research 57, no. 10 (2006): 1073. http://dx.doi.org/10.1071/ar05408.
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Few data are available on litter quantity and quality and decomposition rates over time and what effects stocking rate, grazing method, legume introduction, and fertiliser application may have. Studies were conducted from spring 1997 to 2001 at 3 pasture sites in northern New South Wales to provide such data by examining the effects of pasture treatments on detached litter mass (kg DM/ha) and quality data (percent carbon (C), nitrogen (N) and C : N ratio) collected at 9 sampling times in 2 replicates of 5 (native pasture) or 4 (sown pasture) treatments and examined for differences over time using cubic spline analyses. For each site, decomposition bags were also used to assess differences among treatments for initial and final detached litter mass, organic matter (OM), N values, the relative rate of decomposition (g/g.day), and residence time (days) for periods March to June 1998, June to September 1998, and September to November 1998. Initial and final data were also collected for detached resident and subterranean clover (Trifolium subterraneum) litter for 6 sampling times from September 1998 to January 1999 for a reduced range of treatments at each site. Similar data were collected at each site for resident litter and grass green leaf material from January to April 1999. Detached litter mass declined (P < 0.05) in unfertilised continuously grazed treatments (Barraba native pasture) and with high continuous stocking rate in the Nundle sown pasture. Litter quality was only significantly affected by grazing treatment at the Barraba native pasture site where the fertilised treatment oversown with subterranean clover tended to have low percent C and a lower C : N ratio and higher percent N and microbial biomass C than other treatments. From autumn to spring 1998, the fertilised, oversown treatment at both native pasture sites generally had high litter DM, OM, and N losses and relative rates of decomposition compared with continuously grazed, unfertilised pasture. For the same period, at the Nundle sown pasture site, OM and N losses and the relative rate of decomposition were consistently higher, and residence time lower, in the continuously grazed, high stocking rate treatment compared with all other treatments. Compared with resident detached litter, both subterranean clover litter and green leaf material at the native pasture sites had higher relative decomposition rates and lower residence times. The implications of these data for the management of both native and sown pastures are discussed.
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Lodge, G. M., and S. R. Murphy. "Root depth of native and sown perennial grass-based pastures, North-West Slopes, New South Wales. 1. Estimates from cores and effects of grazing treatments." Australian Journal of Experimental Agriculture 46, no. 3 (2006): 337. http://dx.doi.org/10.1071/ea04276.
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Studies were undertaken on native and sown perennial grass-based pastures as part of the Sustainable Grazing Systems National Experiment to estimate root depth and describe root distribution in these pastures. Samples from soil cores (0–210 cm maximum sampling depth) taken in 1997 (before grazing treatments were imposed) and 4 years later in spring 2001 were used to examine the effects of different grazing regimes on root length density (cm/cm3), root mass density (mg/cm3), root volume density (cm3/cm3), and diameter (mm) at each of 3 sites. In spring 1997, mean maximum root depth was 107 cm for a native perennial grass pasture near Barraba and 74 cm for a pasture sown with phalaris (Phalaris aquatica) and subterranean clover (Trifolium subterraneum) near Nundle, with values being lower for a native pasture near Manilla (65 cm for a Brown Vertosol and 97 cm for a Red Chromosol). For all pasture types, >20% of root mass density, root length density or root volume density was in the 0–5 cm soil layer and >60% was at a depth of 0–30 cm. At all sites, mean total root mass was around 1000 kg DM/ha. After 4 years of grazing (spring 2001) there were relatively few significant effects of grazing treatment on root length density, root mass density, root volume density, or root diameter. Effects that were significant mostly occurred at 0–5 cm for the native pastures and 0–50 cm for the sown pasture. For the Barraba native pasture, root length, volume and mass densities (0–5 cm) were higher (P<0.05) in the continuously grazed, low stocking rate treatment compared with all other treatments. Similarly, for the Manilla native pasture, root length density was higher (P<0.05) in this treatment at soil depths of 0–5 and >5–10 cm compared with all other treatments. In contrast, for the Nundle sown pasture, root length density (0–5 cm) was lowest (P<0.05) in 2 continuously grazed treatments compared with those that were strategically grazed in autumn and spring.
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Pyle, Lysandra A., Linda M. Hall, and Edward W. Bork. "Soil properties in northern temperate pastures do not vary with management practices and are independent of rangeland health." Canadian Journal of Soil Science 99, no. 4 (December 1, 2019): 495–507. http://dx.doi.org/10.1139/cjss-2019-0076.
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Studies examining the influence of disturbance and management history on pasture soils across a large sampling area are uncommon. We report on the soil properties found in 102 northern temperate pastures sampled in central Alberta, Canada, and relate these attributes to ongoing pasture management practices compiled from producer surveys and aboveground measures of rangeland health (RH). Tame pastures, typically seeded to introduced forages, were associated with higher soil fertility (total carbon, nitrogen, and organic matter) than semi-native grasslands, which were associated with coarse-textured soils. Soil properties remained independent of most grazing and pasture management practices, including the grazing systems, class of livestock, fertilization, and stocking rate. However, manure application, often combined with harrowing, was associated with improved soil fertility and increased electrical conductivity (salinity). Soils with a fire history reported by land managers, largely in the Boreal natural region, were characterized by a greater soil C:N ratio. Soil surface properties (litter cover, litter depth, and bare soil) were responsive to grazing management, with growing season and year-round grazing associated with a thinner litter layer having less cover, and bare ground twice as high under continuous grazing compared with pastures rotationally grazed. Further, variation in soil surface cover was associated with contrasting RH classes (healthy, healthy with problems, and unhealthy), whereas soil attributes remained unrelated to RH. This study demonstrates that soils within these northern temperate grasslands are relatively insensitive to many pasture management practices, and highlights that existing RH assessments may provide limited insight into differences in mineral soil properties.
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Wilson, Brian R., and Vanessa E. Lonergan. "Land-use and historical management effects on soil organic carbon in grazing systems on the Northern Tablelands of New South Wales." Soil Research 51, no. 8 (2013): 668. http://dx.doi.org/10.1071/sr12376.
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We examined soil organic carbon (SOC) concentration (mg g–1) and total organic carbon (TOC) stock (Mg ha–1 to 30 cm soil depth) in three pasture systems in northern New South Wales: improved pasture, native pasture, and lightly wooded pasture, at two sampling times (2009 and 2011). No significant difference was found in SOC or TOC between sample times, suggesting that under the conditions we examined, neither 2 years nor an intervening significant rainfall event was sufficient to change the quantity or our capacity to detect SOC, and neither represented a barrier to soil carbon accounting. Low fertility, lightly wooded pastures had a slightly but significantly lower SOC concentration, particularly in the surface soil layers. However, no significant differences in TOC were detected between the three pasture systems studied, and from a carbon estimation perspective, they represent one, single dataset. A wide range in TOC values existed within the dataset that could not be explained by environmental factors. The TOC was weakly but significantly correlated with soil nitrogen and phosphorus, but a more significant pattern seemed to be the association of high TOC with proportionally larger subsoil (0.1–0.3 m) organic carbon storage. This we attribute to historical, long-term rather than contemporary management. Of the SOC fractions, particulate organic carbon (POC) dominated in the surface layers but diminished with depth, whereas the proportion of humic carbon (HUM) and resistant organic carbon (ROC) increased with soil depth. The POC did not differ between the pasture systems but native pasture had larger quantities of HUM and ROC, particularly in the surface soil layers, suggesting that this pasture system tends to accumulate organic carbon in more resistant forms, presumably because of litter input quality and historical management.
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Michez, Adrien, Philippe Lejeune, Sébastien Bauwens, Andriamandroso Herinaina, Yannick Blaise, Eloy Castro Muñoz, Frédéric Lebeau, and Jérôme Bindelle. "Mapping and Monitoring of Biomass and Grazing in Pasture with an Unmanned Aerial System." Remote Sensing 11, no. 5 (February 26, 2019): 473. http://dx.doi.org/10.3390/rs11050473.
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The tools available to farmers to manage grazed pastures and adjust forage demand to grass growth are generally rather static. Unmanned aerial systems (UASs) are interesting versatile tools that can provide relevant 3D information, such as sward height (3D structure), or even describe the physical condition of pastures through the use of spectral information. This study aimed to evaluate the potential of UAS to characterize a pasture’s sward height and above-ground biomass at a very fine spatial scale. The pasture height provided by UAS products showed good agreement (R2 = 0.62) with a reference terrestrial light detection and ranging (LiDAR) dataset. We tested the ability of UAS imagery to model pasture biomass based on three different combinations: UAS sward height, UAS sward multispectral reflectance/vegetation indices, and a combination of both UAS data types. The mixed approach combining the UAS sward height and spectral data performed the best (adj. R2 = 0.49). This approach reached a quality comparable to that of more conventional non-destructive on-field pasture biomass monitoring tools. As all of the UAS variables used in the model fitting process were extracted from spatial information (raster data), a high spatial resolution map of pasture biomass was derived based on the best fitted model. A sward height differences map was also derived from UAS-based sward height maps before and after grazing. Our results demonstrate the potential of UAS imagery as a tool for precision grazing study applications. The UAS approach to height and biomass monitoring was revealed to be a potential alternative to the widely used but time-consuming field approaches. While reaching a similar level of accuracy to the conventional field sampling approach, the UAS approach provides wall-to-wall pasture characterization through very high spatial resolution maps, opening up a new area of research for precision grazing.
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Legg, Mathew, and Stuart Bradley. "Ultrasonic Proximal Sensing of Pasture Biomass." Remote Sensing 11, no. 20 (October 22, 2019): 2459. http://dx.doi.org/10.3390/rs11202459.
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The optimization of pasture food value, known as ‘biomass’, is crucial in the management of the farming of grazing animals and in improving food production for the future. Optical sensing methods, particularly from satellite platforms, provide relatively inexpensive and frequently updated wide-area coverage for monitoring biomass and other forage properties. However, there are also benefits from direct or proximal sensing methods for higher accuracy, more immediate results, and for continuous updates when cloud cover precludes satellite measurements. Direct measurement, by cutting and weighing the pasture, is destructive, and may not give results representative of a larger area of pasture. Proximal sensing methods may also suffer from sampling small areas, and can be generally inaccurate. A new proximal methodology is described here, in which low-frequency ultrasound is used as a sonar to obtain a measure of the vertical variation of the pasture density between the top of the pasture and the ground and to relate this to biomass. The instrument is designed to operate from a farm vehicle moving at up to 20 km h−1, thus allowing a farmer to obtain wide coverage in the normal course of farm operations. This is the only method providing detailed biomass profile information from throughout the entire pasture canopy. An essential feature is the identification of features from the ultrasonic reflectance, which can be related sensibly to biomass, thereby generating a physically-based regression model. The result is significantly improved estimation of pasture biomass, in comparison with other proximal methods. Comparing remotely sensed biomass to the biomass measured via cutting and weighing gives coefficients of determination, R2, in the range of 0.7 to 0.8 for a range of pastures and when operating the farm vehicle at speeds of up to 20 km h−1.
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Bramley, E., I. J. Lean, W. J. Fulkerson, and N. D. Costa. "Feeding management and feeds on dairy farms in New South Wales and Victoria." Animal Production Science 52, no. 1 (2012): 20. http://dx.doi.org/10.1071/an11214.
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Feeding practices in Australian dairy herds were recorded in 100 dairy herds in five districts of two states. A questionnaire about the feeding practices was completed and pasture samples were also collected, where applicable, for analysis. Data and pasture samples were collected once from each farm with visits to regions occurring at different times of the year. Diets were evaluated for nutritional adequacy using the CPM Dairy program. Average milk yield on the day of sampling was 22.8 L/day. The combination of grazed pasture with grain fed during milking was the most prevalent feeding system (54%) in all areas. This was followed by combination of pelleted grain/by-products combined with pasture grazing (25%). Only one herd in the study was not feeding any form of concentrates at the time of sampling. The estimated percentage of concentrate in the diet ranged from 25% ± 11.6 to 44% ± 12.0. Wheat, which was fed at up to 9.8 kg/cow.day DM was the most prevalent grain in all areas, except for Gippsland. The predominant sources of protein in all areas were canola meal, cottonseed meal and lupins. By-products were prevalent, with brewers grain and wheat millrun the most commonly used, fed at 2.8 and 1.6 kg/cow.day DM, respectively. Most farms (81/100) incorporated at least one type of ‘buffer’ in the ration, and limestone (67%) was the most prevalent mineral additive. Monensin and virginiamycin were fed in all areas, with a varying prevalence. Feeding or dose rates used for minerals and rumen modifiers were not always appropriate to those recommended for mineral needs or control of rumen function. This paper demonstrated that a wide variety of feeding systems are used in Australian dairy herds and provides information on nutritive characteristics of pastures.
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Line, Daniel E., William A. Harman, and Gregory D. Jennings. "COMPARING SAMPLING SCHEMES FOR MONITORING POLLUTANT EXPORT FROM A DAIRY PASTURE." Journal of the American Water Resources Association 34, no. 6 (December 1998): 1265–73. http://dx.doi.org/10.1111/j.1752-1688.1998.tb05430.x.
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Turner, David L., and Warren P. Clary. "Sequential Sampling Protocol for Monitoring Pasture Utilization Using Stubble Height Criteria." Journal of Range Management 54, no. 2 (March 2001): 132. http://dx.doi.org/10.2307/4003173.
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McCaughey, W. P., K. Wittenberg, and D. Corrigan. "Methane production by steers on pasture." Canadian Journal of Animal Science 77, no. 3 (September 1, 1997): 519–24. http://dx.doi.org/10.4141/a96-137.
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In order to determine the quantity of methane (CH4) produced by steers on pasture, 16 steers with a mean weight of 356 ± 25 kg were randomly selected from a larger group of cattle (n = 48) to evaluate the effects of grazing management and monensin controlled release capsule (CRC) administration on ruminal CH4 production using the sulphur hexafluoride (SF6) tracer-gas technique. Pasture management treatments consisted of two grazing systems (continuous stocking or 10-paddock rotational stocking) at each of two stocking rates (low, 1.1 steer ha−1 or high, 2.2 steers ha−1) with two replications of each pasture treatment. Half of the animals on each pasture treatment were administered a monensin CRC delivering 270 mg d−1, and untreated animals served as controls. During the 140-d grazing season, one steer from each treatment-replicate combination was sampled to determine daily intake and CH4 production on four occasions. The chemical composition of diets differed between grazing management treatments and sampling periods. Voluntary intake and CH4 production, adjusted for differences in body weight, were unaffected by grazing management, sampling period or by monensin CRC administration and averaged 0.69 ± 0.1 L kg BW−1 d−1 across all grazing management treatments. The energy lost through eructation of CH4 averaged 4.5 ± 1.4% of gross energy intake. Key words: Methane, cattle, environment, digestion efficiency, pasture, forage
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Serrano, João, Shakib Shahidian, Francisco Costa, Emanuel Carreira, Alfredo Pereira, and Mário Carvalho. "Can Soil pH Correction Reduce the Animal Supplementation Needs in the Critical Autumn Period in Mediterranean Montado Ecosystem?" Agronomy 11, no. 3 (March 10, 2021): 514. http://dx.doi.org/10.3390/agronomy11030514.
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Extensive livestock production in Mediterranean climate conditions and acidic soils requires animal feed supplementation. This occurs during the summer and, frequently, also in the autumn and winter, depending on the prevailing rainfall patterns. The purpose of this study was to evaluate the effect of dolomitic limestone application and of tree canopy on availability, quality, and floristic composition of a permanent pasture, grazed by sheep. At the end of autumn, winter, and spring of 2018/2019 and 2019/2020 pasture green and dry matter production (GM and DM, respectively), crude protein (CP), and fiber (neutral detergent fiber) were monitored in 24 sampling points. Half of these points were located in areas amended with dolomitic limestone (COR) and half in unamended areas (UCOR). In each of these, half of the sampling points were located under tree canopy (UTC) and half outside tree canopy (OTC). Pasture floristic composition was monitored in spring 2020. The results show, in autumn, a positive and significant effect (i) of soil pH amendment on pasture DM and CP daily growth rate (kg·ha−1·day−1) (+28.8% and +42.6%, respectively), and (ii) of tree canopy on pasture CP daily growth rate (+26.4%). Both factors affect pasture floristic composition. Pasture species were identified as potential bio-indicators, characteristic of each field area. These results show the practical interest of the soil pH correction to reduce the animal supplementation needs in the critical autumn period in the Mediterranean montado ecosystem.
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Dias, Fabiane Pereira Machado, Ésio de Castro Paes, Flávia de Jesus Nunes, Ana Carolina Rabelo Nonato, Neilon Duarte da Silva, Fabiano de Oliveira de Paula Oliveira, Ludmila Gomes Fereira, and Júlio César Azevedo Nóbrega. "Amostral Optimization of Mechanical Resistance to the Penetration of a Yellow Oxisol Under Pasture." Journal of Agricultural Science 10, no. 9 (August 13, 2018): 275. http://dx.doi.org/10.5539/jas.v10n9p275.
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The degradation of pastures can be characterized by several factors, mainly due to the management adopted, so in view of the country’s territorial extension and the peculiarity of each region and soil type, it is essential to develop research to improve the monitoring of the system. The objective of this study was to evaluate the effect of different sample densities to establish a mesh that gives precision in maps of spatial variability of soil mechanical resistance to root penetration to pasture areas in the coastal tableland region of Northeast Brazil. In a pasture area, three sampling meshes were demarcated for georeferenced evaluation of soil mechanical resistance to root penetration: mesh 1 established in the dimensions of 50 × 50 m, mesh 2 of 100 × 100 m and mesh 3 of 150 × 150 m, totaling an area of 9 ha. The soil resistance to penetration was measured using an automated apparatus, coupled to a tractor. The variation found in the values of penetration resistance in subsurface can be related to the management adopted in the area, as well as the trampling of the animals. Data on soil penetration resistance in pasture showed that the most compacted zone was always below 30 cm depth by using different sample densities. The results allow us to conclude that the higher the density of the sampling mesh, the greater the accuracy of the data and that, independently of the sample mesh, it was possible to identify the layer of higher soil mechanical resistance to root penetration.
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Taylor, Anna R., Randy Dew, Ken Bryan, J. Nathan Pike, and T. Ryan Lock. "173 The effects of Fescue EMTTM Mineral Defense on stocker heifer growth while grazing tall fescue." Journal of Animal Science 97, Supplement_1 (July 2019): 60. http://dx.doi.org/10.1093/jas/skz053.135.
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Abstract Previous research demonstrates grazing tall fescue can decrease reproductive performance and weight gain in cattle. The objective of this study was to evaluate Fescue EMTTM Mineral Defense (Cargill Animal Nutrition, Minneapolis, MN) on summer weight gain in cattle grazing tall fescue pastures in SW Missouri. Heifers (n = 120; initial BW = 236 ± 2.5 kg) were stratified by weight to replicated tall fescue pastures to either a control mineral treatment or Fescue EMT™ Mineral Defense treatment. Forage availability was estimated weekly by ultrasonic sensor. Pasture samples were collected every 21 d and analyzed for ergovaline concentrations. Heifer weights and blood prolactin were measured throughout the trial. Average daily mineral consumption was calculated by mineral offered less residual. Data were analyzed on a pen-mean basis as a completely randomized design using JMP with 6 pens/ treatment and 10 heifers/pen. Prolactin was analyzed as Repeated Measures in JMP. Initial weights between treatments were not different (P > 0.05). Endophyte infection measured 75% or greater in all pastures. No differences were detected in pasture ergovaline (149 ± 19 µg/kg) or pasture availability (2,600 ± 150 kg/ha) between treatments (P > 0.20 at each sampling). Heifer ADG consuming Fescue EMT™ Mineral Defense compared to control mineral was greater at 0.28 kg versus 0.22 kg resulting in total gains of 21.8 kg versus 16.6 kg, respectively (P < 0.05). However, blood prolactin numerically decreased over time in both treatments. Results from this trial demonstrate a 31% improvement in weight gain for cattle consuming Fescue EMTTM Mineral Defense compared with cattle consuming a control mineral while grazing toxic tall fescue.
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Condon, Jason R., A. Scott Black, and Mark K. Conyers. "Simulated sheep urine causes the formation of acidic subsurface layers in soil under field conditions." Soil Research 58, no. 7 (2020): 662. http://dx.doi.org/10.1071/sr20120.
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This study aimed to ascertain whether application of sheep urine led to the development of acidic subsurface layers of a pasture soil. Deionised water or simulated urine solution delivering urea-nitrogen (N) at 44.8 g m–2 and potassium at 25 g m–2 was applied to soil in either winter or spring. Treatments were applied to the soil surface within 10.3 cm internal diameter PVC tubes inserted 20 cm into the soil either under ryegrass or kept bare. Main sampling times corresponded to the completion of various soil N transformations as determined by periodic sampling. Main samplings involved the collection of above ground plant material and soil sampling in 2 cm depth increments in 0–10 cm and 5 cm intervals in 10–20 cm depths. Following treatment application, urea and ammonium-N moved to a depth no greater than 20 cm but the extent of movement was greater in winter than spring due to the influence of initial soil moisture. Following urea hydrolysis, soil pH increased in the 0–15 cm depth. Subsequent nitrification significantly acidified soil under pasture by 0.8–1.0 pH units in the 2–8 and 2–6 cm depths in winter and spring respectively. This created a net acidic subsurface layer of 0.2–0.4 pH units compared with soil at the beginning of the experiment. Subsurface acidification was 0.5–0.7 pH units greater in bare soil compared with the presence of pasture. Transformations of N resulting from application of simulated urine solution formed acidic subsurface layers in the field regardless of the season of application.
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Groppo, J. D., S. R. M. Lins, P. B. Camargo, E. D. Assad, H. S. Pinto, S. C. Martins, P. R. Salgado, et al. "Changes in soil carbon, nitrogen, and phosphorus due to land-use changes in Brazil." Biogeosciences 12, no. 15 (August 7, 2015): 4765–80. http://dx.doi.org/10.5194/bg-12-4765-2015.
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Abstract. In this paper, soil carbon, nitrogen and phosphorus concentrations and stocks were investigated in agricultural and natural areas in 17 plot-level paired sites and in a regional survey encompassing more than 100 pasture soils In the paired sites, elemental soil concentrations and stocks were determined in native vegetation (forests and savannas), pastures and crop–livestock systems (CPSs). Nutrient stocks were calculated for the soil depth intervals 0–10, 0–30, and 0–60 cm for the paired sites and 0–10, and 0–30 cm for the pasture regional survey by sum stocks obtained in each sampling intervals (0–5, 5–10, 10–20, 20–30, 30–40, 40–60 cm). Overall, there were significant differences in soil element concentrations and ratios between different land uses, especially in the surface soil layers. Carbon and nitrogen contents were lower, while phosphorus contents were higher in the pasture and CPS soils than in native vegetation soils. Additionally, soil stoichiometry has changed with changes in land use. The soil C : N ratio was lower in the native vegetation than in the pasture and CPS soils, and the carbon and nitrogen to available phosphorus ratio (PME) decreased from the native vegetation to the pasture to the CPS soils. In the plot-level paired sites, the soil nitrogen stocks were lower in all depth intervals in pasture and in the CPS soils when compared with the native vegetation soils. On the other hand, the soil phosphorus stocks were higher in all depth intervals in agricultural soils when compared with the native vegetation soils. For the regional pasture survey, soil nitrogen and phosphorus stocks were lower in all soil intervals in pasture soils than in native vegetation soils. The nitrogen loss with cultivation observed here is in line with other studies and it seems to be a combination of decreasing organic matter inputs, in cases where crops replaced native forests, with an increase in soil organic matter decomposition that leads to a decrease in the long run. The main cause of the increase in soil phosphorus stocks in the CPS and pastures of the plot-level paired site seems to be linked to phosphorus fertilization by mineral and organics fertilizers. The findings of this paper illustrate that land-use changes that are currently common in Brazil alter soil concentrations, stocks and elemental ratios of carbon, nitrogen and phosphorus. These changes could have an impact on the subsequent vegetation, decreasing soil carbon and increasing nitrogen limitation but alleviating soil phosphorus deficiency.
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Serrano, João, Shakib Shahidian, José Marques da Silva, Luís Paixão, Emanuel Carreira, Rafael Carmona-Cabezas, Julio Nogales-Bueno, and Ana Elisa Rato. "Evaluation of Near Infrared Spectroscopy (NIRS) and Remote Sensing (RS) for Estimating Pasture Quality in Mediterranean Montado Ecosystem." Applied Sciences 10, no. 13 (June 28, 2020): 4463. http://dx.doi.org/10.3390/app10134463.
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Pasture quality monitoring is a key element in the decision making process of a farm manager. Laboratory reference methods for assessing quality parameters such as crude protein (CP) or fibers (neutral detergent fiber: NDF) require collection and analytical procedures involving technicians, time, and reagents, making them laborious and expensive. The objective of this work was to evaluate two technological and expeditious approaches for estimating and monitoring the evolution of the quality parameters in biodiverse Mediterranean pastures: (i) near infrared spectroscopy (NIRS) combined with multivariate data analysis and (ii) remote sensing (RS) based on Sentinel-2 imagery to calculate the normalized difference vegetation index (NDVI) and the normalized difference water index (NDWI). Between February 2018 and March 2019, 21 sampling processes were carried out in nine fields, totaling 398 pasture samples, of which 315 were used during the calibration phase and 83 were used during the validation phase of the NIRS approach. The average reference values of pasture moisture content (PMC), CP, and NDF, obtained in 24 tests carried out between January and May 2019 in eight fields, were used to evaluate the RS accuracy. The results of this study showed significant correlation between NIRS calibration models or spectral indices obtained by remote sensing (NDVIRS and NDWIRS) and reference methods for quantifying pasture quality parameters, both of which open up good prospects for technological-based service providers to develop applications that enable the dynamic management of animal grazing.
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Gourley, C. J. P., and G. S. James. "Predicting the response of irrigated perennial pasture to superphosphate in Victoria." Soil Research 35, no. 2 (1997): 301. http://dx.doi.org/10.1071/s96061.
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Experiments were conducted at 42 sites in the northern and south-eastern irrigation districts of Victoria to determine the relationship between extractable phosphorus (P) using the Olsen P soil test, and response of irrigated perennial pasture to an annual application of superphosphate. Relative responses (the response relative to the maximum yield, P non-limiting) were measured over 4 seasons (summer, autumn, winter, and spring). At 12 of these sites, selected from a range of soils with different clay contents, the effect of clay content on the curvature of the pasture dry mass (DM) response was determined. Different soil-sampling methods, with the surface organic mat included or excluded from the sample, were used to measure Olsen P. A well-defined linear model described the relationship between Olsen P values of soil sampled using these two methods. There was no significant effect of season on the relationship between relative response and Olsen P value. There was also no significant relationship between the curvature of the response to applied P and clay content of the soil. The derived relationship between Olsen P soil test level and relative response to applied fertiliser accounted for only 14 · 6% of the variation and it appears that other factors are markedly affecting irrigated pasture response to applied superphosphate. The accumulation of organic matter on the surface of irrigated perennial pastures may be influencing nutrient availability and pasture growth, and warrants further investigation.
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Townsend, R. J., and T. A. Jackson. "Biocontrol a possibile option to control manuka beetle (Pyronota spp) causing pasture damage on dairy farms on the West Coast." New Zealand Plant Protection 61 (August 1, 2008): 388. http://dx.doi.org/10.30843/nzpp.2008.61.6860.
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Manuka beetle (Pyronota spp Bois Coleoptera Scarabaeidae) has often been reported causing pasture damage frequently in areas close to bush margins Larvae feed on the roots of pasture species producing damage that is often attributed to grass grub (Costelytra zealandica) During 200607 significant pasture damage was observed in dairy pastures established on flipped developments on sandy soils near Cape Foulwind and on hump and hollow developments near Bell Hill north of Lake Brunner Sampling revealed damage was caused by high populations of manuka beetle larvae; no grass grubs were found in either region The common manuka beetle Pyronota festiva was identified from both areas and a second Pyronota species (P edwardsi or P setosa) was found only on the sandy soils at Cape Foulwind A pathogen survey of Pyronota larvae from both regions showed very low levels of infection by bacterial and protozoan pathogens but did reveal moderate infection by the fungi Metarhizium and Beauveria in 3rd instar larvae A laboratory bioassay at 15C showed late third instar Pyronota spp larvae were susceptible to infection by Metarhizium anisopliae and Beauveria bassiana spores mixed into soil Further work will evaluate a promising local Beauveria brongniartii isolate as a biocontrol option against this emerging pest
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Pinto, Alexandrede S., Mercedes M. C. Bustamante, Maria Regina S. S. da Silva, Keith W. Kisselle, Michel Brossard, Ricardo Kruger, Richard G. Zepp, and Roger A. Burke. "Effects of Different Treatments of Pasture Restoration on Soil Trace Gas Emissions in the Cerrados of Central Brazil." Earth Interactions 10, no. 1 (January 1, 2006): 1–26. http://dx.doi.org/10.1175/ei146.1.
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Abstract Planted pastures (mainly Brachiaria spp) are the most extensive land use in the cerrado (savannas of central Brazil) with an area of approximately 50 × 106 ha. The objective of the study was to assess the effects of pasture restoration on the N dynamics (net N mineralization/nitrification, available inorganic N and soil N oxide gas fluxes—NO and N2O), C dynamics (CO2 fluxes and microbial biomass carbon), and diversity of the soil bacterial community using denaturing gradient gel electrophoresis (DGGE) profiles. Sampling was done monthly on a farm in Planaltina, Goiás, Brazil (15°13′S, 47°42′W) from November 2001 to April 2002. Three areas of cerradão (dense cerrado) were converted to pasture (Brachiaria brizantha) in 1991, and after 8 years degradation was evident with the decreasing plant biomass production. Methods to restore these pastures were investigated for their sustainability, principally their effects on trace gas emissions. The pastures have been managed since 1999 as follows: 1) fertilized plot (N = 60 kg ha−1 yr−1, P = 12 kg ha−1 yr−1); 2) grass–legume plot, Brachiaria associated with a legume (Stylosanthes guianensis) with addition of P (12 kg ha−1 yr−1); and 3) a traditional plot without management. A fourth area of cerradão was converted to pasture in 1999 and was not managed (young pasture). Ammonium was the predominant inorganic N form in the soils (∼76 mg N kg−1) for all treatments throughout the study. In December 2001 a reduction in average soil N-NH4+ was observed (∼30 mg N kg−1) compared to November 2001, probably related to plant demand. All plots had high variability of soil N gases emissions, but during the wet season, the NO and N2O soil fluxes were near zero. The results of the water addition experiment made during the dry season (September 2002) indicated that the transition of dry to wet season is an important period for the production of N gases in the fertilized pasture and in the young pasture. Soil CO2 fluxes also increased after the water addition and the grass–legume plot had the highest increase in soil respiration (from ∼2 to 8.3 μmol m−2 s−1). The lowest values of soil respiration and microbial biomass carbon (∼320 mg C kg−1 soil) tended to be observed in the young pasture, because the superficial layer of the soil (0–10 cm) was removed during the conversion to pasture. Trace gas emissions measured after the water addition experiment corresponded to rapid changes in the soil bacterial community. The young pasture sample showed the lowest level of similarity in relation to the others, indicating that the bacterial community is also influenced by the time since conversion. This study indicates that the restoration technique of including Stylosanthes guianensis with B. brizantha increases plant productivity without the peaks of N oxide gas emissions that are often associated with the use of N fertilizers. Additionally, the soil bacterial community structure may be restored to one similar to that of native cerrado grasslands, suggesting that this restoration method may beneficially affect bacterially mediated processes.
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Coates, D. B., and R. M. Dixon. "Faecal near infrared reflectance spectroscopy (F.NIRS) measurements of non-grass proportions in the diet of cattle grazing tropical rangelands." Rangeland Journal 29, no. 1 (2007): 51. http://dx.doi.org/10.1071/rj07011.
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Frequent faecal near infrared reflectance spectroscopy (F.NIRS) analyses of faeces from cattle grazing a range of tropical pastures were used to measure the non-grass component, and other aspects, of their diets. Seasonal profiles of non-grass and crude protein in the diet are presented for nine sites from the speargrass, Aristida–Bothriochloa, and Mitchell grass dominated pasture regions, and for three shrubland sites where browse was plentiful. In grass-dominated native pastures of the speargrass and Aristida–Bothriochloa pasture regions of Queensland where little browse was available, non-grass was usually only 5–15% of the diet. Diet non-grass was even lower for a buffel grass pasture. In uncleared eucalypt woodland in the speargrass region, browse may have contributed up to 20% of the diet in the late dry season when grasses were senesced. In regions with abundant browse (e.g. mulga lands and desert upland systems) cattle preferentially selected actively growing grasses and forbs when they were available. With diminishing availability or declining quality of the forbs and grass due to grazing selection and dry conditions, browse increasingly contributed to intake. In Mitchell grass dominated pastures forbs often comprised more than 50% of the diet, and there appeared to be strong selection for forbs during the dry season. Where browse was available in association with Mitchell grass dominated pastures, it appeared to contribute to intake only in the late dry season. Dry season sampling in monsoonal tallgrass and Mitchell grass dominated pastures indicated dietary crude protein to be linearly correlated with diet non-grass, demonstrating the importance of non-grass in the prevention or alleviation of dry season protein deficiency in cattle. Changes in diet selected by cattle in relation to season and rainfall were generally in accord with the previous limited information, largely with sheep, in comparable vegetation systems. The results demonstrate the value of F.NIRS technology to assist understanding of diet selection by grazing cattle in northern Australia.
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Hill, N. S., J. A. Stuedemann, G. O. Ware, and J. C. Petersen. "Pasture Sampling Requirement for near Infrared Reflectance Spectroscopy Estimates of Botanical Composition." Crop Science 29, no. 3 (May 1989): 774–77. http://dx.doi.org/10.2135/cropsci1989.0011183x002900030047x.
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Vulich, S. A., J. P. Hanrahan, and E. G. O’Riordan. "Evaluation of pasture sampling procedures for the estimation of herbage n-alkanes." Proceedings of the British Society of Animal Production (1972) 1992 (March 1992): 171. http://dx.doi.org/10.1017/s0308229600022819.
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The assessment of herbage intake using the n-alkane technique requires estimates of the n-alkane concentrations in the diet. The objective of the present study was a) to assess the magnitude of sampling variation in n-alkane concentrations among herbage samples taken from individual oesophageal fistulated wethers, b) compare n-alkane concentrations determined from oesophageal extrusa, hand plucked, and mechanically clipped herbage samples and c) assess the effect of errors in the estimates of herbage n-alkane concentrations on the accuracy of intake estimates.
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Acharya, Roshani S., Timothy Leslie, Emily Fitting, Joan Burke, Kelly Loftin, and Neelendra K. Joshi. "Color of Pan Trap Influences Sampling of Bees in Livestock Pasture Ecosystem." Biology 10, no. 5 (May 19, 2021): 445. http://dx.doi.org/10.3390/biology10050445.
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The decline in insect pollinators has increased the importance of accurately monitoring pollinator diversity and abundance over time. Sampling techniques include the use of passive insect traps such as pan traps, yet there is still discussion over their utility and effectiveness in different ecosystems. The objective was to examine four different colors of pan traps (blue, green, yellow, and purple) for their utility in sampling bees in native forages rotationally grazed by sheep and to compare the relative abundance, richness, similarity, and community assemblage patterns among the four trap colors. Most bees were from the Halictidae family (89%). The most abundant species were Lasioglossum imitatum (42.2%), Augochlorella aurata (8.3%), L. subviridatum (6.8), Agapostemon texanus (6.4), and L. birkmani (4.1%). Blue color traps exhibited the highest rates of bee capture and species accumulation. Purple and yellow colored traps were moderately effective in capturing bees, while the green color pan traps were least effective. Similarly, observed and extrapolated species richness was highest in blue trap, followed by purple, yellow, and green. Notably, the blue trap captured the highest number of unique species, followed by purple, yellow and green traps. Considering the total number of insects collected (including bees and other insects), yellow and green traps captured a significantly higher number of insects than other colored traps. The light reflectance from blue, purple, green and yellow pan traps had peaks at ~450, 400, 550, and 600 nm, respectively. Since different insects respond to different light intensities, wavelengths, and reflectivity, these results could be used to guide future trapping protocols targeting certain insect groups in livestock pasture and similar ecosystems.
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Jacobs, J. L., F. R. McKenzie, S. E. Rigby, and G. Kearney. "Effect of nitrogen fertiliser application and length of lock up on dairy pasture dry matter yield and quality for silage in south-western Victoria." Australian Journal of Experimental Agriculture 38, no. 3 (1998): 219. http://dx.doi.org/10.1071/ea97151.
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Summary. This study aimed to define the effect of differing rates of nitrogen application and lock up length on harvested material for silage in south-western Victoria. At 2 sites in south-western Victoria, 140, 3 by 2 m plots of predominantly perennial ryegrass pasture were randomly allocated, within 4 replicate blocks. Five nitrogen fertiliser rates (0, 25, 50, 75, 100 kg N/ha) in combination with 7 lock up lengths were randomly allocated to the 35 plots within each replicate. Nitrogen was applied 1 week after initial lock up (September 10, site 1; September 12, site 2) and harvesting commenced 3 weeks after initial lock up. For each treatment and harvest date, dry matter yield and botanical composition were determined and samples of total pasture and the ryegrass fraction were collected and chemically analysed for dry matter digestibility, crude protein, neutral detergent fibre, water-soluble carbohydrates and mineral content. Metabolisable energy was derived from dry matter digestibility. Increasing rates of nitrogen increased herbage dry matter yield regardless of length of lock up. The yield response was greatest 8 weeks after initial lock up at both sites (site 1, 26 kg DM/kg N; site 2, 14.9 kg DM/kg N). Subsequent regrowth of pasture was increased by nitrogen application over shorter lock up lengths (weeks 3 and 4). Botanical composition was unaffected by treatment during the harvesting period or in the subsequent autumn. Application of nitrogen gave rise to a linear increase in pasture metabolisable energy and crude protein content at both sites until week 5. Thereafter, this response diminished and by week 8 there was a decrease in metabolisable energy and crude protein content. Neutral detergent fibre content was relatively unaffected by nitrogen application until week 8 of the study, at which point there was a linear increase. Application of nitrogen reduced the water-soluble carbohydrate content of pastures throughout the sampling period. It is concluded that application of nitrogen to a mixed sward locked up for silage can increase dry matter yield and, provided pasture is harvested before ryegrass ear emergence, can also have a positive effect on metabolisable energy and crude protein. Given that the decision for removing paddocks from the grazing rotation is based upon pasture growth and stocking rates, the use of nitrogen fertilisers on higher stocked farms could lead to increased dry matter yield over shorter lock up periods. On farms with lower stocking rates shorter lock up periods may allow for pastures to be returned to the grazing rotation earlier, or provide the opportunity for a second harvest of pasture for silage.
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Martínez-Falcón, Ana Paola, Gustavo A. Zurita, Ilse J. Ortega-Martínez, and Claudia E. Moreno. "Populations and assemblages living on the edge: dung beetles responses to forests-pasture ecotones." PeerJ 6 (December 13, 2018): e6148. http://dx.doi.org/10.7717/peerj.6148.
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Edge effects alter insect biodiversity in several ways. However, we still have a limited understanding on simultaneous responses of ecological populations and assemblages to ecotones, especially in human modified landscapes. We analyze edge effects on dung beetle populations and assemblages between livestock pastures and native temperate forests (Juniperusand pine-oak forests (POFs)) to describe how species abundances and assemblage parameters respond to edge effects through gradients in forest-pasture ecotones. InJuniperusforest 13 species avoided the ecotones: six species showed greater abundance in forest interior and seven in pasturelands, while the other two species had a neutral response to the edge. In a different way, in POF we found five species avoiding the edge (four with greater abundance in pastures and only one in forest), two species had a neutral response, and two showed a unimodal pattern of abundance near to the edge. At the assemblage level edge effects are masked, as species richness, diversity, functional richness, functional evenness, and compositional incidence dissimilarity did not vary along forest-pasture ecotones. However, total abundance and functional divergence showed higher values in pastures in one of the two sampling localities. Also, assemblage similarity based on species’ abundance showed a peak near to the edge in POF. We propose that conservation efforts in human-managed landscapes should focus on mitigating current and delayed edge effects. Ecotone management will be crucial in livestock dominated landscapes to conserve regional biodiversity and the environmental services carried out by dung beetles.
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Reppert, Emily J., Kathryn E. Reif, Shawnee R. Montgomery, Geraldine Magnin, Yuntao Zhang, Tomas Martin-Jimenez, K. C. Olson, and Johann F. Coetzee. "Determination of plasma-chlortetracycline (CTC) concentrations in grazing beef cattle fed one of four FDA approved free-choice CTC-medicated minerals." Translational Animal Science 4, no. 2 (April 1, 2020): 1128–33. http://dx.doi.org/10.1093/tas/txaa048.
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Abstract Control of active bovine anaplasmosis in the United States is predicated on the use of chlortetracycline (CTC)-medicated feed throughout the vector season. However, data describing population pharmacokinetics of chlortetracycline in cows, on pasture, having free-choice access to CTC-medicated mineral for consecutive months is lacking. This study documented plasma-CTC concentrations in grazing cows during peak vector season in an anaplasmosis endemic herd. Each pasture was administered one of the four Food and Drug Administration approved CTC-medicated mineral formulations and were assigned as follows: 0.77 g/kg, Aureo Anaplaz C700 Pressed (Sweetlix Livestock Supplements, Mankato, MN); 5.5 g/kg, Purina Anaplasmosis Block (Purina Animal Nutrition, Gray Summit, MO); 6.6 g/kg, Stockmaster Aureo FC C6000 Mineral (Hubbard Feeds, Mankato, MN); 8.8 g/kg, MoorMan’s Special Range Minerals AU 168XFE (ADM Animal Nutrition, Quincy, IL). Blood samples were collected monthly for determining plasma drug concentration by Ultra performance liquid chromatography (UPLC) and mass spectrometry. Continued plasma-CTC monitoring allowed for characterization of trends between treatment groups (pastures), age groups (<3 yr or >4 yr), and sampling times (June to October). Results indicate formulation (pasture) and time were significant factors affecting concentrations of CTC in plasma. Cows exposed to 5.5 g/kg block formulation recorded higher CTC plasma concentrations compared with other pasture groups (P = 0.037). Plasma-CTC concentrations increased over time (month of measurement; P = 0.0005). Specifically, concentrations measured after 5 months of continuous CTC treatment were higher than those measured in earlier months.
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Plaza, Tarik Godoy D., and Carla Galbiati. "Influence of Flood Pulse on Termite Diversity (INSECTA: ISOPTERA) in the Pantanal." Sociobiology 64, no. 3 (October 17, 2017): 310. http://dx.doi.org/10.13102/sociobiology.v64i3.1371.
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This research aimed to associate termite diversity to flood pulse by Paraguay River, and with savannas and pasture areas. The study was conducted nearby the town of Cáceres, in Pantanal - Mato Grosso, on six livestock farms subject to Paraguay River flood pulse. Types of land use sampled were native savanna and cultivated pasture. Flooded and dry plots were selected, both the savanna and the pasture in each sampling area. Termite richness and abundance was analysed based on the environments as an explanatory variable (FP – flooded pasture, DP – dry pasture, FS – flooded savanna, DS – dry savanna) through GLM; Tukey’s test was subsequently performed to determine whether land use and/or flood pulse can significantly affect the termite community. There were 37 termite species and 19 genera. Richness and abundance of termite species cannot be explain by flooding pulse, but were explained only by land use (pasture and savanna). The similarity analysis also identified that species composition was quite affected by flood in grazing areas, but this disturbance does not affect the savanna areas. In conclusion, flood pulse is not a determining factor for savannas or pasture termite richness, but change the composition of the termite fauna in the environment.
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Hill, N. S., F. N. Thompson, J. A. Stuedemann, D. L. Dawe, and E. E. Hiatt. "Urinary Alkaloid Excretion as a Diagnostic Tool for Fescue Toxicosis in Cattle." Journal of Veterinary Diagnostic Investigation 12, no. 3 (May 2000): 210–17. http://dx.doi.org/10.1177/104063870001200303.
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Fescue toxicosis research studies have often included serum prolactin as a physiologic index of the disorder. Serum prolactin has not been used as a clinical measure of fescue toxicosis because of variation associated with sex and physiologic condition of the animal and climatic and seasonal factors. The primary excretory route of the alkaloids responsible for this toxicosis is the urine. Three pasture experiments were conducted to examine serum prolactin and urinary ergot alkaloid variability among steers continuously grazing endophyte-infected (E+) or endophyte-free (E-) tall fescue and among steers that were switched from one pasture form to the other. A fourth grazing experiment was used to examine how to best to manage the steers prior to sampling for urinary ergot alkaloid excretion. Coefficients of variability for urinary alkaloid excretion were consistently lower (46–65%) than serum prolactin (64–142%). Urinary alkaloid excretion patterns changed within 12 hours following switching steers from E+ to E- pasture or visa versa, but serum prolactin was recalcitrant to change. Because it is less variable and more dynamic than serum prolactin, urinary alkaloid excretion can be used for health assessment of steers grazing E+ and E- pastures. Regression analysis established a quadratic relationship between alkaloid excretion and average daily weight gain, with a regression coefficient of 0.86. Urinary alkaloid analysis was useful in determining whether cattle were consuming toxic tall fescue.
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Dobos, R. C., F. A. P. Alvarenga, H. Bansi, K. L. Austin, A. J. Donaldson, R. T. Woodgate, and P. L. Greenwood. "Mapping variability of pasture sward height, dry matter availability and disappearance during grazing." Crop and Pasture Science 72, no. 7 (2021): 551. http://dx.doi.org/10.1071/cp20347.
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This study investigated whether geostatistical methods can be applied to severely drought-affected pastures to assess spatial variability in sward height (SH) and dry matter yield (DMY) and change in SH and DM in response to grazing. Geo-referenced SH data were collected using a rapid, non-destructive method (rapid pasture meter) and analysed by geostatistical methodology. Eight severely drought-affected paddocks (~1.25 ha) were grazed individually by two groups of 20 Angus heifers in two 28-day phases (P1 and P2) between 2 July and 29 August 2019. Pasture DMY was estimated from calibration equations developed for P1 and P2. Ordinary kriging was used to generate estimated surface forming maps with which to visualise the spatial variability. The degree of spatial dependence (dSD) was strongest for SH during P2 post-grazing (11%) and for DMY during P2 pre-grazing (6%). For change in SH, the dSD was 50% for P1 and 0% for P2. Disappearance of DMY dSD was 56% for P1 and 47% for P2. The range of spatial dependence (distance until variability stabilised) for both SH and DMY was lowest for P1 post-grazing (11 m), indicating that intensive sampling is required. The ranges of spatial dependence for the change in both SH and DMY were similar for P1 and P2. These results confirm that intensity of grazing by cattle is not random. Incorporation of this methodology into rapid, non-destructive pasture data collection devices would assist producers and their advisers in improving grazing management decisions. Further analysis with data from non-drought affected pastures is required to determine the robustness of this method.
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Fannin, F. F., D. Kubly, Y. Wang, and L. P. Bush. "Epidemiological study with the mare and Neotyphodium coenophialum toxins." NZGA: Research and Practice Series 13 (January 1, 2007): 423–25. http://dx.doi.org/10.33584/rps.13.2006.3114.
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The objective of this study was to relate chemical components of pastures containing tall fescue suspected to be causative to reduced conception and early embryonic death in the mare. Pasture sampling was conducted on 143 pastures and over 500 sites during mare breeding. Tall fescue was 16- 42% of the forage in most pastures and about 65% of the plants were infected with Neotyphodium coenophialum. Ergovaline content ranged from 0 to 2220 ng/g. Lysergic acid was present in equal or lesser amounts than ergovaline. Approximately 10% of the mares did not conceive or had early foetal loss. Because of other components in the diet, a direct cause/effect relationship cannot be made between mare response and N. coenophialum related toxins. These results suggest that a large number of animals will be required when designing an experiment to show how tall fescue might affect reproduction in mares. Keywords: horse pastures, alkaloids, minerals
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Degens, Bradley P., and Maja Vojvodi´c-Vukovi´c. "A sampling strategy to assess the effects of land use on microbial functional diversity in soils." Soil Research 37, no. 4 (1999): 593. http://dx.doi.org/10.1071/sr98091.
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A suitable sampling strategy is necessary for broad-scale investigations of the effects of land use on microbial functional diversity in soils. We report on the development of procedures for sampling and handling field soils for assessment of heterotrophic functional diversity [by analysis of catabolic response profiles (CRPs)]. Individual CRPs were subject to factor analysis and the results were used for statistical comparisons of the soils. Transect sampling comparing CRPs in forest with pasture showed that most variation was attributable to differences between land uses, followed by field replication and laboratory replication. Differences in CRPs between pasture compared with pine forest, horticultural cropping, or maize cropping could also be determined by a similar sampling strategy. Variation in CRPs between land uses by using these sampling approaches was greater than variation within land uses. CRPs varied little between seasons in 2 land uses and samples could also be stored up to 5 months at 5°C with little change in CRPs. We recommend that microbial functional diversity (CRPs) can be assessed in different land uses without laboratory replication and that transect sampling strategies are suitable for distinguishing clear differences between land uses.
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Baxter, Lisa L., Charles P. West, C. Philip Brown, and Paul E. Green. "Comparing Nondestructive Sampling Techniques for Predicting Forage Mass in Alfalfa-Tall Wheatgrass Pasture." Agronomy Journal 109, no. 5 (September 2017): 2097–106. http://dx.doi.org/10.2134/agronj2016.12.0738.
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Barker, G. M., and P. J. Addison. "Sampling Argentine stem weevil,Listronotus bonariensis(Kuschel), populations in pasture: the egg stage." New Zealand Journal of Agricultural Research 33, no. 4 (October 1990): 649–59. http://dx.doi.org/10.1080/00288233.1990.10428469.
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Peña-Domene, Marinés, Cristina Martínez-Garza, Luz Ayestarán-Hernández, and Henry Howe. "Plant Attributes that Drive Dispersal and Establishment Limitation in Tropical Agricultural Landscapes." Forests 9, no. 10 (October 10, 2018): 620. http://dx.doi.org/10.3390/f9100620.
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Factors that influence tropical-forest regeneration have been of interest across the tropics. We tested the degree of dispersal and establishment limitation of pioneer and non-pioneer tree species with different dispersal modes and seed sizes, using data on both seed fall and seedling establishment in primary forest, secondary forest, and pasture excluded from livestock. The study took place in a lowland tropical rain forest in southeastern Mexico. To calculate dispersal and establishment limitation, we used a density-weighted index that considers: (1) whether a seed or seedling of a given species has arrived in the sample area; and (2) the fraction of seeds or seedlings contributed by a given species relative to the total number of seeds or seedlings arriving at a sampling station. Dispersal limitation of non-pioneer species and animal-dispersed species decreased with succession. The secondary forest had less dispersal limitation for wind-dispersed pioneers than pasture, resulting in a dense aggregation of species with seeds dispersed by wind. Overall, establishment limitation differed between animal-dispersed and wind-dispersed species in the primary forest, and was negatively correlated with seed size. The low capacity of most species to arrive, germinate, and establish as seedlings in pastures slows succession back to forest. To overcome barriers to natural succession in pastures, transplanting seedlings of non-pioneer species is suggested because most of them show high dispersal and establishment limitation.
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Robaina, A. C., C. Grainger, P. Moate, J. Taylor, and J. Stewart. "Responses to grain feeding by grazing dairy cows." Australian Journal of Experimental Agriculture 38, no. 6 (1998): 541. http://dx.doi.org/10.1071/ea97087.
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Summary. Two experiments were conducted on feeding grain supplements to dairy cows during summer. In experiment 1, dairy cows in mid–late lactation were offered one of 2 pasture allowances (about 20 and 40 kg DM/cow.day) with and without a supplement of a grain mix (5 kg of a 70 : 30 mixture of barley and lupins). This experiment was conducted twice over 2 consecutive summer–autumn periods (years 1 and 2). Milk yields were higher at the high pasture allowance and with grain feeding. The marginal response to grain feeding (kg milk/kg grain DM consumed) was 0.7 at both pasture allowances in year 1, and 1.1 and 0.8 at the low and high pasture allowance, respectively, in year 2. Diet had no significant effect on milk composition. Pasture intake was reduced by supplementary feeding and the level of substitution depended on pasture allowance. The alkane-based and sward sampling techniques were used to estimate pasture intake and diet digestibility. Estimates of pasture substitution, based on measurements made with the alkane technique, were 0.3 and 0.6 kg DM reduction in pasture/kg DM grain consumed at the low and high pasture allowance, respectively, in both years. In year 1, the pasture substitution measured with the pasture difference method was 1 kg pasture DM/kg grain DM at both pasture allowances. In year 2, estimates of substitution calculated using the pasture difference method were 0.2 and 0.5 kg pasture DM/kg grain DM at the low and high pasture allowance respectively. In the second experiment (year 3), the effects of level of feeding barley on pasture intake, diet digestibility and milk production were measured during summer. The 4 levels of grain consumed were 0, 1.8, 3.4 and 6.7 kg barley DM/cow. day. Higher grain intake resulted in higher milk yield, higher protein concentration and yields of fat, protein and lactose. Milk yield responses per kilogram of barley diminished from 1.6 at the low barley intake to 0.8 kg milk/kg barley DM at the highest barley intake. It is suggested that higher levels of substitution and a potentially less efficient use of grain contributed to the poorer production responses at higher levels of grain feeding.
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Reed, K. F. M., Z. N. Nie, L. V. Walker, and G. Kearney. "Fluctuations in the concentration of ergovaline and lolitrem B produced by the wild-type endophyte (Neotyphodium lolii) in perennial ryegrass (Lolium perenne) pasture." Animal Production Science 51, no. 12 (2011): 1098. http://dx.doi.org/10.1071/an11143.
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Mammalian toxins produced by the wild-type endophyte, Neotyphodium lolii, in perennial ryegrass (PRG) pasture cause production losses and animal health and welfare problems in livestock. Managing this risk is limited by the lack of information on fluctuations in the concentration of toxin in Australian pasture. We investigated how the toxin concentrations may be related to recent observations of weather. Swards sown from common seedlots of two cultivars of wild endophyte-infected PRG, grazed short by sheep, were sampled at 2–4 weekly intervals from spring to autumn at two sites in Victoria. The highest concentration of ergovaline and lolitrem B was observed at Hamilton, the site with the longer-growing season. The concentration of ergovaline peaked in early summer, coinciding with seed development, and declined through summer, before increasing with the commencement of autumn growth. The concentration of lolitrem B remained low in summer, then rose in autumn. Variation between the two cultivars in the concentration of toxins was small and rarely significant. The concentration of ergovaline declined as the mean daily maximum temperature over the preceding 1–5 days increased. Similarly, for lolitrem B, the concentration declined over the temperature range 12−20°C, from 1.3 to 0.3 mg/kg. At Hamilton, where solar radiation and soil temperature were recorded, both were superior to maximum temperature for predicting lolitrem B. Serial sampling of PRG from old naturalised pasture on seven farms across south-eastern Australia found two seasonal peaks for both alkaloids in most pastures. The concentration of ergovaline reached or exceeded tolerance levels for livestock in 23 of 43 samples, compared with 5 of 43 for lolitrem B. Ergovaline concentrations initially peaked (at 1.0–1.6 mg/kg) when mature reproductive material was present (coinciding with peduncle elongation and seed development). In pastures with low grazing pressure, i.e. where growth was allowed to continue through summer, ergovaline concentration was relatively low (<0.7 mg/kg) but in a hard-grazed pasture (sward height 3 cm), the ergovaline concentration was greater (up to 1.1 mg/kg). Concentration of lolitrem B also peaked in December, except on pasture where growth continued through summer. High concentrations of lolitrem B associated with neurotoxic signs in sheep (viz. 2.4–3.9 mg/kg) were observed only in mid-summer and autumn, and only if conditions favoured growth or where close grazing by sheep left the crown as the dominant source of herbage.