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Grazing management and nitrogen fertilisation may affect forage accumulation (FA), nutritive value, and grazing efficiency (GE) of the highly productive 'Zuri' guineagrass [Megathyrsus maximus (Jacq.) B.K.Simon & S.W.L. Jacobs syn. Panicum maximum Jacq.]. The objective of this study was to assess the effects of pre‐graze canopy heights [55 and 75 cm (H55 and H75, respectively)] and N fertilisation rates [150 and 300 kg N ha−1 year−1 (N150 and N300, respectively)] on FA, GE, grazing losses (GL), and nutritive value of Zuri under rotational stocking. The stubble height was 50% of the pre‐graze canopy height. The total FA was 20% greater under H75 than H55 (22,120 vs. 18,370 kg DM ha−1 year−1), as well as the GL was greater under H75 (85%) than under H55 (79%). Regardless of pre‐graze height, the upper stratum of the canopy was composed mostly of leaves contributing to similar crude protein (CP) (142 g kg−1) and in vitro digestible organic matter (IVDOM) (559 g kg−1) concentrations. Greater N rate (N300) increased FA (23,500 vs. 16,980 kg DM ha−1 year−1) and resulted in greater GE (84% vs. 80%) compared to N150. The CP and IVDOM concentrations under N300 (157 and 571 g kg−1, respectively) were greater than under N150 (128 and 547 g kg−1). Zuri guineagrass grazed at H75 has great FA and GE, maintaining a similar forage nutritive value compared to H55. [ABSTRACT FROM AUTHOR]

One of the main constraints for sheep production in tropical and subtropical areas is the lack of knowledge of how to manage erect tropical grasses for lambs. The objective of this study was to assess the effect of pasture height and structure of an erect tropical grass, Aruana Guinea grass (Megathyrsus maximus cv. IZ-5) on the intake and performance of young weaned lambs. The experiment was repeated in two consecutive years. Thirty young weaned lambs were equally assigned, each year, to three pasture heights: (1) Tall 75 cm; (2) Medium 50 cm and (3) Short 25 cm. Herbage mass (HM), pasture height, plant morphological composition, pasture nutritional quality, lambs' average daily gain, gain per hectare and herbage intake were measured. The Short treatment had higher (p < 0.05) leaf:stem ratio (L:S; 2.6 ± 0.27) and average daily gain (ADG; 92 ± 10 g day−1) than the Tall treatment (0.9 ± 0.11 and 40 ± 13 g, respectively). The Medium treatment showed intermediate ADG (69 ± 11 g) and L:S ratio (1.4 ± 0.09). The height of the pasture affects the rate at which the number of stems increases relative to the number of leaves. There was a significant interaction between treatment and period (summer and early autumn) for herbage intake. Intake decreased markedly on the Tall treatment from the first to the second period. This study showed that for a better performance of weaned young lambs during summer–autumn, it is important to maintain tropical swards at a short height (25 cm). However, if the grass height exceeds this condition, the use of cattle or a mower are good options to maintain the sward height. [ABSTRACT FROM AUTHOR]

Combinations between crop intercropping and forage production in a no-tillage system are not well established for environments under low water retention and soil fertility conditions. Our study aimed to evaluate the potential interactions between soybean-grass intercropping with residual nitrogen in a no-tillage system. The experimental design was a randomized block with four replications in a subdivided plot scheme. The main plots in the summer season were: 1) soybean monoculture; 2) soybean - Aruana Guinea grass (Megathyrsus maximus cv. Aruana) intercropping, and 3) soybean - Congo grass (Urochloa ruziziensis cv. Comum) intercropping. The subplots were the nitrogen rates of 0, 50, 100, and 150 kg ha-1, applied as side-dressing in maize and grasses during the autumn-winter season. Here, the results of the summer seasons are shown. To do so, the parameters evaluated were soybean agronomic traits, dry biomass production, and macronutrient concentrations of plants intercropped. The main effects and interactions were studied. Our findings showed that soybean-Aruana Guinea grass intercropping is an alternative to no-tillage system implementation. Moreover, residual nitrogen from the autumn-winter season directly interfered with the dry biomass production of grasses intercropped with soybeans in the summer season. In short, the systems studied seem suitable for implementing a no-tillage system, which aims to neutralize degraded pastures and produce forage for ensilage. Despite the changes in macronutrient concentrations within the intercropping system and residual nitrogen, and among intercropped crops over the years, Congo grass intercropped with soybeans in the summer season showed great capacity for phosphorus, potassium, and magnesium cycling. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the forage mass and nutritional value (NV) of Guinea Massai grass (Megathyrsus maximus × Megathyrsus infestum) in an open pasture (OP) or the silvopastoral system (SPS) at different stages of development (SDs). The experimental design was completely randomized, with five replications. The treatments were distributed in a factorial scheme 2 × 4, corresponding to types of systems (OP and SPS) and four SD (vegetative stage—S1, pre-flowering—S2, full flowering—S3 and maturity after flowering—S4). There was no interaction of the system × stage of plant development in any of the variables evaluated. The production of forage mass and Guinea Massai grass morphological components did not differ (p > 0.05) between SPS and OP. However, they differed between the SDs (p ≤ 0.05), with an increasing linear effect for forage mass, percentage of the stem, and dead material, and decreasing for leaf percentage and leaf: stem ratio. Only protein content differed (p < 0.05) among the chemical composition variables between culture systems. The shading caused by the SPS did not decrease the forage mass, NV, and in vitro dry matter digestibility of Guinea Massai grass compared to the system in OP. The advance of the SD of Guinea Massai grass increases the forage mass, with higher proportions of morphological components of low NV, such as stem and dead material. Silvopastoral system of Guinea Massai grass and eucalyptus is effective to prolongate the grazing season, with a greater amount of green leaves in the sward and better NV, without compromising herbage mass production in the forage growing season. [ABSTRACT FROM AUTHOR]

A two‐year experiment assessed herbage production and above‐ and below‐ground characteristics of a highly productive monoculture ('BRS Zuri' guineagrass [Panicum maximum Jacq.]) and two mixtures of three grasses (Mixture 1: 'BRS Zuri' guineagrass, 'BRS Xaraés' palisadegrass [Brachiaria brizantha Stapf.], and 'Basilisk' signalgrass [Brachiaria decumbens Stapf.]; Mixture 2: 'BRS Quênia' guineagrass [Panicum maximum Jacq.], 'Marandu' palisadegrass [Brachiaria brizantha Stapf.], and 'BRS Paiaguás' palisadegrass [Brachiaria brizantha Stapf.]), cultivated in the Brazilian tropical savanna. Mixtures 1 and 2 were subjected to two grazing intensities (removal of 40 or 60% of pre‐grazing height) and 'BRS Zuri' guineagrass monoculture was defoliated to a single grazing intensity of 50%. Treatments were randomly assigned to fifteen 0.25‐ha plots and managed under intermittent stocking by cattle. Herbage accumulation rate was similar among pastures and years (p >.1). The root mass in the tussocks did not differ (p >.1), with mean values ranging between 0.62 to 1.81 kg DM m−2. Root density in the tussock interspaces was greater in the mixtures (p <.001), regardless of seasons (p =.405) and years (p =.292). The mixtures were dominated by guineagrass (70%) and palisadegrass (30%) at the end of the experiment, with the population of 'Basilisk' and 'BRS Paiaguás' being completely suppressed throughout the experimental period. Mixing guineagrass and brachiariagrasses can be an alternative to the traditional pastoral systems in the tropics, as it does not compromise herbage production and presents a capacity to produce more roots than a very productive monoculture of 'BRS Zuri' guineagrass. [ABSTRACT FROM AUTHOR]

Due to the compacting of cow manure in the dairy farms, it is rarely used in the pasture and forage areas, resulting in low agricultural yields and low milk production. This work was developed during five years in five dairy farms of the “El Tablón” Livestock Enterprise, Cienfuegos, through the manufacture and application to the soil of natural organo-mineral fertilizer (Zeofert) with the objective of increasing the yield of pasture and forage. For the preparation of Zeofert, fresh cow dung deposited by the animals on the floor of the shaded sheds was used and mixed with 1-3 mm particles of natural zeolitic rock (Fertisol). The obtained decompacted manure (2,362 t) was applied manually on 94.5 ha of pasture and forage at a rate of 25 t ha -1 . The results showed that the application of Zeofert to the soil significantly increased the yield of Panicum maximum Jacq. cultivar ‘Common’ (natural grass) and P. maximum cultivar ‘Likoni’ (guinea grass) by 52 % and of Pennisetum purpureum Schum. (king grass) cultivar ‘CT-115’ by 77 %, while milk production was increased by 20 %, all with respect to the control. The return of nutrients to the soil was restored, with a significant increase in the contents of P2O5, K2O, organic matter and pH values. The use of 99, 124 and 116 t of NH4NO3, simple supersulfate and KCl were substituted as equivalent chemical fertilizers, respectively. The use of this technology is recommended in those units that have cattle in stabled or semistabled conditions. [ABSTRACT FROM AUTHOR]

Nitrogen fertilization has been recognized as an essential tool towards the establishment of sustainable intensification of pasture-based livestock systems using tropical perennial grasses if, for a given ecosystem it is capable of increasing forage growth, stocking rates and animal performance. This study assessed pasture growth traits, nutritive value, animal and economic responses of Panicum maximum cv. Mombaça guinea grass pastures subjected to different levels of N fertilization (100 (N100), 200 (N200), and 300 (N300) kg N ha−1 yr−1). Pastures were managed under rotational stocking to maintain similar pre (80–90 cm) and post-grazing (45 cm) canopy heights. A partial budget and a Benefit–Cost Analysis were used to assess the economic returns on increasing N fertilization. N300 resulted in greater post-grazing herbage mass. A slightly higher neutral fiber and acid lignin detergent was observed at N100 (P < 0.05); crude protein increased linearly, and in vitro digestible organic matter reached maximum value at 265.4 kg N ha−1 yr−1. Annual averages of animal weight gain were 515, 590 and 660 g d−1, respectively, for N100, N200 and N300. There was a decrease from 3.7 to 1.9 kg of body weight gain per kg of additional N applied when increasing N rates from 100 to 200 and from 100 to 300 kg ha−1. The net profit improved with increasing N levels, but at reducing rates, reaching its maximum at the N300 level. The change from 100 to 200 kg N ha−1 presented the best return, with USD 3.73 for each additional dollar invested, while the change from 200 kg N ha−1 to 300 kg N ha−1 was economically less than optimal, recouping only USD 1.60 for each dollar. The N300 rate presented the highest net profit per hectare (accounting profit), even in a pessimist scenario (25% reduction in production). Despite being profitable, the N300 rate was less than optimal from an economic standpoint, since an additional 100 kg of Nitrogen ha−1 to change from N200 to N300 level reduced both the net returns and the Benefit–Cost ratio. Our results suggest that the economically optimal level of N fertilization for Mombaça guinea grass pasture should be between 200 and 300 kg ha−1. [ABSTRACT FROM AUTHOR]

Introduction: Fertilization is a cultural practice of utmost importance in the productive response of crops. Specifically, in tropical grasses and forages, alternatives should be sought to improve performance, without affecting the agronomic and economic efficiency of the source used. Diatomaceous soil (diatomite) is a ground natural rock, made up of microfossils of seaweed with high silica content and is beginning to be used globally as a natural fertilizer. There are currently very few research works on the use of diatomite as fertilizer in pastures. Objective: To evaluate the agronomic and nutritional response of diatomite in Guinea grass cv Mombasa. Methods: Four treatments (doses) of diatomite (T0 = Natural Fertility T1=850 kg/ha, T2=1,600 kg/ha and T3=2,500 kg/ha) were evaluated under a Completely Random Design, in containers with soil volume of 1,300 g. Each container constituted the E.U., with five repetitions per treatment (dose). Dry matter production (kg/ha), dry matter (%), H/T ratio, height (cm), NDF (%), CP (%) and DIVMS (%) were evaluated as experimental variables. Results and Discussion: Dry matter production was significantly higher (P=0.01) for T2 and T3 (257 g/container and 280 g/container) vs T0 and T1 (156 g/container and 151 g/container). Height was higher (P=0.01) for T2 (49.8 cm) vs T0, T1 and T3 (33.8, 34.4 and 33.9) respectively. The percentage of dry matter was higher (P=0.01) for T1 (39.05%) in relation to the other treatments (22.47%, 32.16% and 28.11%, for T0, T2 and T3). The H/T ratio was significantly higher (P=0.01) in the Diatomite treatments (3.75; 3.49; 3.20 vs 2.75 in T0). No significant statistical differences were found in the nutritional variables for the four treatments. Conclusion: Diatomite is a viable alternative to improve some agronomic variables of Guinea grass, especially dry forage production. [ABSTRACT FROM AUTHOR]

Tropical pasture canopy characteristics can alter lamb ingestive behavior. Our study evaluated the ingestive behavior of young lambs in different tropical pastures to identify which variables interfere in their grazing activity. Two years of study were carried out with 54 weaned lambs distributed in three different pasture canopies: 1) monoculture of an upright grass, guinea grass (Panicum maximum; GG); 2) monoculture of a shrubby legume pigeon pea (Cajanus cajan; PP) and 3) contiguous paddock with half GG and half PP (GP). The experiment was set out in a randomized complete block design (3 blocks). Lamb ingestive behavior was observed from sunrise to sunset with records every 5 minutes. To identify the main variables that affected lamb grazing activity, a multivariate analysis of the Decision Tree was performed. Our results showed that there was no difference in the ingestive behavior parameters of young lambs in different canopies (P > 0.05). There was interaction among the canopies and the experimental periods for the variables idleness time and biting rate (P ≤ 0.05). Lambs in all canopies showed more idleness time in the first evaluation period. Lambs in canopies containing grass (GG and GP) exhibited greater bites per minute throughout the experimental period. Lamb grazing time increased 40% as experimental period progressed and plants matured. The Decision Tree identified leaf:stem ratio as the variable that most influenced lamb grazing time in GG and GP canopies while in the PP, grazing time was directly related to canopy height. The behavior of young lambs on tropical pasture is variable as there is a change in the behavioral response to canopy characteristics over time. In addition, the grazing time of these animals can be estimated by means of variables related to canopy structural characteristics (leaf:stem ratio and height) together with chemical variables. [ABSTRACT FROM AUTHOR]

The aim of this study was to quantify and verify the defoliation dynamics process of the Panicum maximum, Brachiaria brizantha, and Brachiaria decumbens intercropping during the formation of four grazing horizons in lenient grazing intensities and high grazing intensity. Pastures were managed in a pregrazing height of 70 cm, and as post-grazing height, the criteria of 40% and 60% were used in relation to the pre-grazing height. The experimental design used was a completely randomized design with a 3x4 factorial arrangement. The first factor was the cultivars of intercropped grasses consisted of 3 cultivars, i.e., BRS Zuri, Xaraés, and Basilisk. The second factor was grazing horizons consisted of 4 levels, i.e., I: one; II: two; III: three; IV: four. In the intercropping managed with 40% of the forage canopy height removal, oscillations were observed in the severity of defoliation of the extended tiller among the intercropped species, in which the tiller reduction of the 'Basilisk' was 32% lower in relation to 'BRS Zuri'. In the intercropping managed with 60% of the forage canopy height removal intensity, disproportionality was observed among the grasses, because the 'Basilisk' suffered a higher severity and frequency of pseudostem defoliation. In intercropped pastures managed under grazing intensities of 40%, as the animal explores the grazing horizons, the vertical distribution of the pseudostem could modify the shape and positioning of the depth of the bite, leading the animal to perform less selective grazing among the species. Due to the higher supply of pseudostem mass at the intensity of 60%, it was possible to infer that there was a reduction in forage intake. [ABSTRACT FROM AUTHOR]

African mahogany (Khaya spp.) produces high-value wood, and its cultivation is expanding in tropical regions. The silvopastoral system is an alternative method for growing timber trees, but may involve cattle stripping bark from trees, which limits its usefulness. We evaluated cattle bark-stripping rates in two African mahogany species, K. grandifoliola and K. senegalensis, in a silvopastoral system with Guinea grass, Panicum maximum, in South-eastern Brazil. Cattle had free access to plantations of both tree species for 2 weeks in May 2018 and July 2019, when trees were 5 and 6 years old, respectively. In 2018, we found bark-stripping only in K. grandifoliola, but in 2019 both species were bark-stripped. The proportion of bark-stripped trees was higher for K. grandifoliola than for K. senegalensis. Considering both years, 29/155 (18.7%) K. senegalensis trees and 106/153 (69.3%) K. grandifoliola trees had some of their bark-stripped by cattle. Bark-stripped trees had lower trunk diameter growth than unaffected trees, and their growth was affected by the degree of bark-stripping. Some trees were girdled by bark-stripping. These trees dried up, and some of them fell down 1 year after girdling. In 2019, despite the high herbage mass, levels of crude protein in the pasture were very low, which may have stimulated bark-stripping. Although we could not identify the reasons for bark-stripping, we recommend avoiding the use of silvopastoral systems with cattle and African mahogany in times of the year when pasture has a low quality. [ABSTRACT FROM AUTHOR]

Aims: To identify factors driving soil respiration (Rsoil) in a tropical C4-dominated perennial managed grassland ecosystem exposed to elevated carbon (C) dioxide concentration ([CO2]) and temperature. Methods: The perennial grass Panicum maximum was grown at 600 μmol CO2 mol−1 and + 2 °C above ambient temperatures for one full growing cycle (from grazing to regrowth for about ~30–45 days) using a free-air CO2 and infrared warming system. Plant growth and CO2 fluxes were measured during the growing cycle. Results: Both high [CO2] and warming increased canopy photosynthesis but warming alone increased biomass by 53% and Rsoil by 26%. There was a strong diel effect on Rsoil, which was 16% greater at noon than at 18:00 h. Rsoil had low sensitivity to soil temperature (Q10 ~ 1) regardless of the CO2 treatment. Conclusions: In this tropical managed pasture, diel variation in photosynthesis strongly affected Rsoil, suggesting that Rsoil may be more limited by substrate availability than abiotic factors such as temperature. Predicted changes in climate for the region will likely affect the C dynamics of C4-dominated tropical pastures. Although, the short-term experiment may limit the extrapolations of our findings, the highly controlled settings of the experiment highlighted the role of canopy photosynthesis on Rsoil respiration in tropical C4-pastures. [ABSTRACT FROM AUTHOR]

Cultivated pastures may increase the meat production of sheep, but it is necessary to understand the plant-animal relationships in a pastoral environment. This study aimed to assess the effect of forage cultivars on the intake and feeding behavior of sheep. Four treatments were evaluated, consisted of the cultivars Panicum maximum cvs. Aruana and Massai and Brachiaria brizantha cvs. Marandu and Piatã. Twenty-four sheep, male of the Santa Inês genotype, were used with six replications per treatment. Daily forage and nutrient intakes were evaluated in addition to time in grazing, rumination, and leisure activities. The animals in the pasture of Aruana grass demanded the most extended times of grazing and rumination (p<0.05). The leisure time was higher (p<0.05) in the animals kept in pastures of Piatã grass. The highest intakes of dry matter and crude protein in g/day (p<0.05) were found in the animals kept in the pasture of Marandu grass, and a smaller intake was found in the animals kept in the pasture of Massai grass. Intake of leaf blades was higher (p<0.05) in the animals kept in pastures of Massai and Marandu. The neutral detergent fiber intake did not differ among the cultivars. It is concluded that pasture structure and chemical composition of tropical forage cultivars influence the nutrient intake and feeding behavior of sheep. The low leaf blade offer of the pasture of the Aruana grass negatively affects the feeding behavior of the sheep, but the crude protein in forage of this cultivar favors the nutrient intake, feed conversion, and performance of sheep. [ABSTRACT FROM AUTHOR]

The nutritional requirements can be met, and carcass quality can be achieved by using concentrate supplementation in the diets of grazing lambs. This study evaluated the effects of different concentrate supplementation rates (0 %, 1.5 %, and 3 % of body weight) and tropical pastures (Panicum maximum cv. 'Aruana' and Brachiaria brizantha cv. 'Marandu') on lamb carcass traits. Thirty-six male Suffolk lambs, with an initial body weight of 22.54 ± 2.72 kg , were evaluated in a 3 × 2 factorial experimental design. The concentrate used consisted of milled soybean, maize, and oat grains. The pasture species affected empty body weight and commercial cuts. The use of concentrate supplementation affected carcass weight, yield, indexes, and commercial cuts. Also, the use of concentrate supplementation improved the weight of muscle and fat content. Based on discriminant analysis it is possible to identify the rearing systems, when all variables where used, or the level of concentrate supplementation when variables of weight were used. Carcasses of animals on grass-only diets were different and easier to discriminate. The use of concentrate supplementation on rearing lambs improves the quality of carcass traits. The period of finishing can be shorted with supplementation of 3 % of body weigh in Aruana and Marandu grass. The discriminant analysis can identify the differences between rearing systems based on all carcass traits. This analysis can be used to develop carcass traceability systems. [ABSTRACT FROM AUTHOR]

Panicum maximum Jacq. 'Mombaça' (Guinea grass) is a C4 forage grass widely used in tropical pastures for cattle feeding. In this study, we evaluated the isolated and combined effects of warming and elevated CO2 concentration [CO2] during summer on nutrient content, nutrient accumulation, nutrient use efficiency and growth of P. maximum under field conditions. Field temperature and [CO2] were controlled by temperature free-air controlled enhancement and free-air CO2 enrichment systems, respectively. We tested two levels of canopy temperature: ambient temperature (aT) and 2°C above ambient temperature (eT), as well as two levels of atmospheric [CO2]: ambient [CO2] (aCO2) and 200 ppm above ambient CO2 (eCO2). The experiment was established in a completely randomized design with four replications, in a 2×2 factorial scheme. After pasture establishment, plants were exposed to the treatments during 30 days, with evaluations at 9, 16, 23 and 30 days after the treatments started. Results were dependent on the time of the evaluation, but in the last evaluation (beginning of the grazing), contents of N, K, Mg and S did not change as a function of treatments. However, P decreased as a function of warming under both levels of [CO2], and Ca increased under [eCO2] combined with warming. There was an increase in root dry mass under warming treatment. Combined treatment increased N, Ca and S accumulation without a corresponding increase in the use efficiency of these same nutrients, indicating that the fertiliser dose should increase in the next decades due to climate change. Our short-term results in young and well fertilized pasture suggest that under the combination of [eCO2] and eT conditions, P. maximum productivity will increase and the nutritional requirement for N, Ca and S will also increase. [ABSTRACT FROM AUTHOR]

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Tropical pastures can be important natural sources of antioxidant compounds and may impact production and quality of animal protein with repercussions on human health. The objective of this study was to evaluate the concentrations of α-tocopherol, condensed tannin (CT) and nutritional values of important tropical species used in grazing. The species included guinea grass (Panicum maximum), bermudagrass (Cynodon spp.), pigeon pea (Cajanus cajan), soybean (Glycine max), creeping beggarweed (Desmodium incanum), macrocephala stylo (Stylosanthes macrocephala) and pinto rhizoma peanut (Arachis pintoii). The species were distributed in a randomised block design with four replicates each. There were no differences in α-tocopherol between the mid and late growing season; there were likewise no differences among forage species. The highest (P = 0.02) concentrations of CT were observed in creeping beggarweed (66.5 ± 13.8 g kg−1 dry matter [DM]), pinto (15.7 ± 5.2 g kg−1 DM) and pigeon pea (8.7 ± 0.8 g kg−1 DM). Among these species, creeping beggarweed showed the highest percentage of extractable CTs (68% of total CT) and was the only species where the CT showed biological activity (protein precipitation by phenols = 60.1 g kg−1 DM). Among the tropical grasses and legumes, creeping beggarweed could become an important CT source for animal production. [ABSTRACT FROM AUTHOR]

Objectives of this study were to evaluate effects of grazing tropical forage species and level of supplementation with grain on characteristics of lamb meat. Ninety-day-old lambs (n = 36) (22.54 ± 2.72 kg) were randomly assigned to a 2 x 3 factorial arrangement of pasture types (Aruana and Marandu) and levels of concentrate supplementation (0%, 1.5% and 3% of bodyweight). Water retention capacity, shear force, weight loss after cooking, pH, colour, and intramuscular lipid content of the meat were evaluated. A panel of 145 consumers evaluated the appearance, flavour, fat flavour, odour, and softness of the meat and provided an overall assessment. Supplementation at 3% of bodyweight reduced the luminosity of the meat. The appearance of meat from lambs that grazed Aruana grass was deemed preferable to that of meat from lambs that grazed Marandu grass. Total branched-chain fatty acids (BCFAs) were increased when grazing Marandu grass compared to Aruana grass. Lambs supplemented with concentrate had reduced BCFA/kg of meat and its content of both monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids were increased. Supplementation with concentrate at 1.5% and 3.0% of bodyweight increased n-6 PUFAs by 16.8% and 90.0%, decreased n-3 PUFAs by 49.7% and 35.9%, and thus increased the n-6/n-3 ratio by 135.0% and 183.8%, respectively. Lambs that were finished on grass without supplementation had a more healthful fatty acid profile and received better scores for flavour and global appreciation. To improve the quality of fatty acids in the meat, the pasture system is recommended. [ABSTRACT FROM AUTHOR]

Traditional cassava cultivation involves mechanical manipulation of the soil with one plowing and two harrowings, a practice that may generate problems such as soil erosion, compaction and nutrient loss. These issues may be even bigger in sandy soils. The objective of this study was to evaluate the cassava roots components and the soil physical attributes in planting rows and between planting rows in tillage systems substituting the conventional tillage before the Mombasa grass pasture (Panicum maximum), in Northwestern Paraná, Brazil. Soil tillage treatments in 2014 were carried out as follows: conventional (disc harrow, moldboard plow and disking), minimum (disc harrow and chisel plow - clod breaking) and zero tillage. In 2015, soil samples were collected in layers 0.0-0.1, 0.1-0.2 and 0.2-0.4 m deep, between, and within cassava planting rows, for soil bulk density and macroporosity determinations. Number of plants, number of tuberous roots per plant, fresh and dry mass of cassava tuberous roots were evaluated as well. The soil physical attributes within the planting rows negatively affected the production of cassava tuberous roots in zero tillage in succession to the Mombasa grass pasture. The minimum and conventional tillage systems did not present soil physical limitations to the cassava yield components in succession to Mombasa grass pasture. Minimum tillage may be an alternative to conventional tillage without compromising soil physical attributes and cassava root yield in the Mombasa pastureland reform areas, in northwestern Paraná. [ABSTRACT FROM AUTHOR]

Copyright of Revista Caatinga is the property of Revista Caatinga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tropical Grasslands / Forrajes Tropicales is the property of International Centre for Tropical Agriculture - CIAT and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Eighty-four Nellore bulls (269 ± 27 kg; 13 months) were used in a completely randomized design to evaluate different supplementation strategies on the performance of growing Nellore cattle grazing Panicum maximum cv. Tanzania in the rainy season and rainy-to-dry season transition. In the rainy season, 42 animals received mineral salt (MS) ad libitum and 42 received protein supplement (PR) at 1 g kg−1 body weight (BW). In the rainy-to-dry season transition, 28 animals received MS, 28 received PR at 1 g kg−1 BW, and 28 received a protein-energy (PE) supplement at 3 g kg−1 BW. In the rainy season, the PR supplement increased average daily gain (ADG), providing a significant increase of 17 kg in final BW. In the first period of the rainy-to-dry season transition, PE promoted better performance than MS, while PR did not differ from the two other treatments. In the second period of the rainy-to-dry season transition, PE and PR increased ADG by 41% and 31%, respectively, compared with MS. In the third period, all supplements differed from each other. Bulls fed PE had greater final BW compared with animals fed PR and MS. In conclusion, during the rainy season, PR supplementation should be provided even under good pasture conditions. Also, during the rainy-to-dry season transition, protein-energy supplementation is recommended to compensate for quantitative and qualitative deficiencies of the pasture. Nellore cattle being backgrounded on pasture with supplementation has greater body weight in the feedlot entry. Supplementation is recommended to compensate for quantitative and qualitative deficiencies of the pasture. Supplementation promotes a positive response in animal performance. [ABSTRACT FROM AUTHOR]

Abstract: In swards of tall, tufted, tropical grasses like Mombaça guinea grass (Panicum maximum (Jacq.)), post‐grazing heights promote changes in sward structure, which influence animal performance. This study evaluated changes in sward structure in response to grazing management at two post‐grazing heights (30 and 50 cm), associated with 90 cm pre‐grazing height. Each treatment was allocated to experimental unit (1.5 ha) in three replicated blocks. Pastures were evaluated pre‐ and post‐grazing to estimate herbage mass, percentages of leaf (LP), stem (SP) and dead material (DP), and nutritive value (VN). Stocking rate was adjusted twice a week “using the put‐and‐take approach,” and animals were weighed every 28 days. Forage accumulation rate was greater for pasture managed at 30 cm (64.8 vs. 55.1 kg ha−1 day−1) than 50 cm. A greater number of days were required after grazing 30‐cm residual pasture to achieve the pre‐grazing target height, resulting in 25% decrease in number of grazing cycles compared with pastures managed at 50 cm. Regardless of post‐grazing height targets, SP and DP decreased, whereas LP and NV increased from soil level to top of canopy. Stocking rate was greater in pastures managed to 30 cm than in those managed to 50 cm residual height (4.7 vs. 3.4 AU ha−1). However, average daily gain was greater for 50 cm than for 30 cm post‐grazing height (795 vs. 590 g steer−1 day−1), resulting in a greater animal production per area (917 vs. 794 kg/ha of live weight). Thus, Mombaça guinea grass subject to intermittent grazing should be managed at 50 cm residual height. [ABSTRACT FROM AUTHOR]

Purpose: Cadmium has caused serious environmental problems due to its phytotoxicity, requiring solutions to reduce its concentration in the environment. Because S can alleviate the phytotoxicity caused by heavy metals, the evaluation of the effects of S supply is a promising approach to address this problem. The aim of this study was to determine the influence of S in reducing the phytotoxicity caused by Cd to Panicum maximum Jacq. cv. Tanzania (guinea grass) and to evaluate the potential of this grass for Cd phytoextraction. Materials and methods: Tanzania guinea grass was cultivated in a nutrient solution to evaluate the combinations of five rates of S (0.1, 1.0, 1.9, 2.8, and 3.7 mmol L) and five rates of Cd (0.0, 0.5, 1.0, 1.5, and 2.0 mmol L), in a 5 fractional factorial design with six replications. Six plants were grown per pot in two growth periods to evaluate the effect of Cd on the establishment (51 days of age) and on the regrowth (18 days of growth) of the plants. During regrowth, Cd was not supplied in the nutrient solution. At the end of each growth period, growth parameters, concentrations of S and Cd, Cd transport factor, and concentrations of hydrogen peroxide (HO), malondialdehyde, reduced glutathione, and oxidized glutathione were evaluated. Results and discussion: On the establishment of Tanzania guinea grass, application of Cd reduced mass production by 39 % due to the increases in the concentration of Cd (30 times compared with the treatment without Cd) and in lipid peroxidation (124 %). During regrowth, the residual effect of Cd resulted in a lower number of tillers (62 %) and leaves (89 %) caused by the increase in concentrations of Cd, HO (49 %), and lipid peroxidation, which resulted in a 65 % lower dry mass production. The proper supply of S reduced concentration of Cd and tiller mortality rate due to the residual effect of Cd on the regrowth of the grass. Mass production by the roots was 43 % lower because of Cd, but the transport of Cd from roots to shoots increased. The increase in the concentration of glutathione (GSH) associated with a possible higher activity of antioxidant enzymes alleviated the phytotoxic effects of Cd on the guinea grass. Conclusions: The supply of S reduces the phytotoxicity caused by Cd to guinea grass, especially during the regrowth of the plant, when the concentration of Cd is higher because of the transport from roots to shoots. Tanzania guinea grass showed to be very promising for phytoextraction of Cd due to its high mass production, even when Cd was largely available in the nutrient solution. [ABSTRACT FROM AUTHOR]

Copyright of Tropical Grasslands / Forrajes Tropicales is the property of International Centre for Tropical Agriculture - CIAT and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ciência Animal Brasileira is the property of Universidade Federal de Goias, Escola de Veterinaria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of this work was to develop and evaluate agrometeorological models to simulate the production of Guineagrass. For this purpose, we used forage yield from 54 growing periods between December 2004-January 2007 and April 2010-March 2012 in irrigated and non-irrigated pastures in São Carlos, São Paulo state, Brazil (latitude 21°57′42″ S, longitude 47°50′28″ W and altitude 860 m). Initially we performed linear regressions between the agrometeorological variables and the average dry matter accumulation rate for irrigated conditions. Then we determined the effect of soil water availability on the relative forage yield considering irrigated and non-irrigated pastures, by means of segmented linear regression among water balance and relative production variables (dry matter accumulation rates with and without irrigation). The models generated were evaluated with independent data related to 21 growing periods without irrigation in the same location, from eight growing periods in 2000 and 13 growing periods between December 2004-January 2007 and April 2010-March 2012. The results obtained show the satisfactory predictive capacity of the agrometeorological models under irrigated conditions based on univariate regression (mean temperature, minimum temperature and potential evapotranspiration or degreedays) or multivariate regression. The response of irrigation on production was well correlated with the climatological water balance variables (ratio between actual and potential evapotranspiration or between actual and maximum soil water storage). The models that performed best for estimating Guineagrass yield without irrigation were based on minimum temperature corrected by relative soil water storage, determined by the ratio between the actual soil water storage and the soil water holding capacity.irrigation in the same location, in 2000, 2010 and 2011. The results obtained show the satisfactory predictive capacity of the agrometeorological models under irrigated conditions based on univariate regression (mean temperature, potential evapotranspiration or degree-days) or multivariate regression. The response of irrigation on production was well correlated with the climatological water balance variables (ratio between actual and potential evapotranspiration or between actual and maximum soil water storage). The models that performed best for estimating Guineagrass yield without irrigation were based on degree-days corrected by the water deficit factor. [ABSTRACT FROM AUTHOR]

In a grassland of common guinea grass (Panicum maximum, Jacq), damaged and invaded by the wiregrass (Sporobolus indicus), the influence of sowing different varieties of improved grasses on the control of wiregrass was studied. The treatments were distributed in a random block design with four replicates: a) plantation of Pennisetum purpureum cv. Cuba CT-115, b) plantation of Cynodon nlemfuensis cv. Star grass, c) sowing of Brachiaria decumbens cv. Basilisk, d) sowing of Panicum maximum cv. Likoni and f) sowing of Panicum maximum cv. Mombaza. At the begining, there were no significant differences on the population and height of the wiregrass. Its population was reduced from 7 to less than 0.9 plant/ m² at the end of the experiment in all treatments. In the two samplings conducted with the variaties sown, the highest pasture height (P < 0.001) was found in Cuba CT-115 and the lowest values were presented in star grass and brachiaria. At the end of the experiment, the lowest (P < 0.01) population of wiregrass (0.26 plants/m²) was presented where sowing guinea Likoni. The number of tillers/plant of wiregrass was lower when brachiaria was planted, without differing from the treatments where CT-115 or guinea Likoni were sown. Guinea Mombaza and Cuba CT-115 were the variaties less invaded by weeds in general and ended with more than 98 % of pureness. Star grass and brachiaria had less than 50 % of pureness. Guinea Likoni had an intermediate performance. The highest biomass production (P < 0.001) and the lowest (P < 0.001) cost/t/ha of GM and DM produced were reached when Cuba CT-115 was planted. An intermediate value for this measurement was achieved in Guinea Mombaza. The results of this study indicate that the use of improved pastures could be an option for the control of wiregrass by renewing or with new sowings. A good agrotechnical management is recommended as well as taking care of the soil fertility after controlling the wiregrass. [ABSTRACT FROM AUTHOR]

The influence of wire grass (Sporobolus indicus. L) (0, 2, 4 and 6 plants/m²) on yield, cost and quality of Guinea grass (Panicum maximum Jacq cv. Likoni) biomass was studied in a calcic ferralic soil, through a completely random design and ten repetitions. The wire grass height did not vary with the increase of its population and the area of the soil covered was increased (P < 0.001). There was an inverse ratio (r = -0.88) (P < 0.001) between Guinea grass yield and wire grass population. The forage cost increased from 25.21 to 78.63 pesos, for 0 and 6 plants of wire grass/m², respectively. The chemical composition of the soil did not vary with the treatments. The highest wire grass population produced lower (P < 0.05) content of organic matter digestibility (OMD) and Ca (P < 0.01). There was no effect on the chemical composition of Guinea grass. In the wire grass, only CP and P were lower (P < 0.01) with the population increase. It is concluded that the increase of wire grass population diminished the Guinea grass yield, elevated the cost of biomass production and altered some indicators of forage quality. Further studies on the possible effects of wire grass population on biomass quality of improved pastures are recommended. [ABSTRACT FROM AUTHOR]

The economic viability of finishing sheep on Tanzania grass under intermittent grazing was evaluated with four concentrate supplementation levels (0; 0.6; 1.2 and 1.8% LW), two herd separation systems (electric and net fence) and three pasture sizes (1.0; 3.0 and 5.0 ha). The analysis was carried out to determine the minimal necessary conditions to have a viable business. Net income, benefitcost ratio, net present value and internal rate of return with an interest of rate of 8.75% per year were verified. The total implantation cost and maintenance to each system was estimated according to Fortaleza/CE market. Sale price between R$ 2.60 to 3.20/kg LW was considered to estimate total budget. The pasture sized 1.0 ha was economically unviable for both kinds of system tested. The system with net fence was more expensive than the one with electric fence. For the systems with supplementation, data showed viability only for a sale price above R$ 3.00/kg LW and, in some cases, in areas above 5.0 ha. [ABSTRACT FROM AUTHOR]

Durante tres años consecutivos se determinó el comportamiento de numerosos indicadores del suelo y del pasto en dos tipos de pastizales silvopastoriles basados en Leucaena leucocephala-Panicum maximum, para seleccionar los que mostraron mayor variabilidad, determinar los más útiles y conocer el grado de estabilidad del sistema suelo-pasto, de modo que pueda darse seguimiento al efecto del manejo al cual se someten. Los pastizales fueron: a) silvopastoreo ubicado en un suelo Ferralítico Rojo Hidratado con seis años en explotación y b) silvopastoreo ubicado en un suelo Ferralítico Rojo Lixiviado con cinco años en explotación. Mediante el análisis de componentes principales se obtuvieron tres grupos de indicadores: vegetación, indicadores físico-químicos e indicadores biológicos del suelo. Se escogieron los que tuvieron valor de preponderancia mayor de ± 0.78 y que explicaron, al menos, 65 % de la varianza acumulada. En la vegetación se estudiaron hasta 50 indicadores, de los que se seleccionaron 7 y 9 (para seis y cinco años en explotación, respectivamente). En ellos coincidieron la cobertura vegetal, el suelo desnudo, la densidad del pasto base y la presencia de pastos naturales. De los 76 indicadores del suelo, se seleccionaron 15 y 19 (para seis y cinco años en explotación, respectivamente). En ellos, la distribución de agregados en húmedo y en seco, la estabilidad estructural, el valor n, la fitomasa subterránea, la macrofauna y la mesofauna se reiteraron para explicar su variabilidad. Ambos sistemas silvopastoriles progresaron en el tiempo por el incremento de la población del pasto base y su estabilidad productiva, así como por la mejora de sus características edáficas. El comportamiento de los indicadores seleccionados permitió caracterizar el estado del sistema suelo- planta de cada pastizal y mostró que el manejo a que se sometieron ambos pastizales influyó en su mejora ecológica y productiva. Se presentan tablas con rangos de valores de confianza para los indicadores seleccionados, los que podrán servir como herramientas útiles, confiables y sensibles para conocer los cambios que ocurren en cada tipo de pastizal y que podrán usarse en la investigación, la docencia y la producción. [ABSTRACT FROM AUTHOR]

A study was carried out at the Experimental Station of Pastures and Forages "Indio Hatuey", Matanzas, with the objective of determining the litter decomposition of Panicum maximum and its relationship to some of the biotic and abiotic factors. The litter decomposition was determined as the loss of biomass in time, with regards to the initial weight. For the study of the decomposition dynamics the method of litter bags was used. The bags measured 10 x 10 x 10 cm, with pores of 1 cm diameter, which allows access inside of a wide range of the edaphic biota. Forty bags that contained litter of P. maximum were distributed randomly. In each bag 20 g of previously collected litter (dry base) were put. The results showed that the decomposition process of P. maximum litter was slow, because 210 days after being deposited the litter still showed 45,3% of its initial weight, with a higher decomposition rate in the first 30 days. In the remnant material of the process of litter decomposition, the N-NDF concentration increased. The taxonomic composition of the fauna associated to the decomposition process was constituted by three phyla, five classes, eight orders, seven genera and seven determined species. The presence of a diverse and stable fauna associated to the bags influenced the process of litter decomposition. The species Venezillo sp., Nagarus sp. and Pycnocelus surinamensis were the ones with higher presence during the whole process. The mathematical model that shows the effect of temperature, relative humidity and rainfall, showed the best adjustment in the process of litter decomposition in this pastureland. [ABSTRACT FROM AUTHOR]

A study was carried out at the Experimental Station of Pastures and Forages "Indio Hatuey", Matanzas, Cuba, with the objective of determining the litter accumulation in a pastureland of Panicum maximum Jacq cv . Likoni and in a silvopastoral system of Panicum maximum and Leucaena leucocephala (Lam) de Wit cv. Cunningham. In the P. ma x imum pasturelands of both systems the litter accumulation was determined by means of the technique proposed by Bruce and Ebershon (1982), while the litter of L. leucocephala accumulated in the silvopastoral system was determined according to Santa Regina et al. (1997). In general, the results showed that in both pasturelands the Guinea grass accumulated a lower quantity of litter during the June-December period, stage in which its highest vegetative development occurs. In leucaena, the highest litter production occurred in the December-January period, associated to the natural fall of its leaves that is produced due to the effect of the lower temperatures and the scarce moisture in the soil. In the silvopastoral system the leucaena litter represented the highest percentage of weight within the total production, with a higher nitrogen and calcium content than the litter of the herbaceous stratum. In the Guinea grass the rainfall was the climatic factor that showed higher negative correlation with the litter production in both systems, and in leucaena the highest negative correlation was found with the lowest temperature. [ABSTRACT FROM AUTHOR]

A study was carried out at the Experimental Station of Pastures and Forages "Indio Hatuey", Matanzas, Cuba, with the objective of determining the litter accumulation in a pastureland of Panicum maximum Jacq cv. Likoni and in a silvopastoral system of Panicum maximum and Leucaena leucocephala (Lam) de Wit cv. Cunningham. In the P. maximum pasturelands of both systems the litter accumulation was determined by means of the technique proposed by Bruce and Ebershon (1982), while the litter of L. leucocephala accumulated in the silvopastoral system was determined according to Santa Regina et al. (1997). In general, the results showed that in both pasturelands the Guinea grass accumulated a lower quantity of litter during the June- December period, stage in which its highest vegetative development occurs. In leucaena, the highest litter production occurred in the December-January period, associated to the natural fall of its leaves that is produced due to the effect of the lower temperatures and the scarce moisture in the soil. In the silvopastoral system the leucaena litter represented the highest percentage of weight within the total production, with a higher nitrogen and calcium content than the litter of the herbaceous stratum. In the Guinea grass the rainfall was the climatic factor that showed higher negative correlation with the litter production in both systems, and in leucaena the highest negative correlation was found with the lowest temperature. [ABSTRACT FROM AUTHOR]

With the objective of describing the performance of the herbaceous stratum of an association of Morus alba (Linn.) and Panicum maximum cv. Likoni, with different distances between rows (1, 2 and 3 m) and cutting heights (10, 100 and 200 cm) under grazing conditions with cattle, a research was carried out at the EEPF "Indio Hatuey", in Cuba, using a randomized block design with 3 × 3 factorial arrangement and three repetitions. The dispersion percentages of the base pasture (P. maximum), natural pastures, herbaceous legumes, weeds and the depopulation were measured. An increase in the occurrence frequency of P. maximum was observed with regards to the initial rotation (85,0 vs 69,0%); while the distance between rows and cutting height in the tree caused discreet numerical variations. Natural pastures, creeping legumes and weeds, in total did not exceed 11% of the covered area and only the second ones showed slight increases with the increasing distances between rows (0,64; 2,23 and 2,54%). Towards the conclusion of the experiment, depopulation was lower than 1%. The results allow to conclude that the grassland evolved positively due to the increase of the base pasture population, the decrease of depopulated area and the discreet variability in the occurrence percentages of the weed species. The distance between rows and cutting height cause numerical variations of little importance in the herbaceous stratum. To increase the evaluation period is recommended in order to elucidate the effect of the studied variables on the evolution of the botanical composition of the system. [ABSTRACT FROM AUTHOR]

This article provides information on a study that investigated the fattening performance in the grazing when animals consume the granulated product Jordán. A number of yearling steers of the Zebu breed were used in this study in a grazing area of Guine grass and star grass. The amount of granulated product given to the animals was cited. Results of the study showed an inverse correlation between pasture and animal intake. The study also found a change in the time of grazing, rumination and resting habits of the animals.

Simple Summary: Biometric measurements have been used to estimate the composition and yield of sheep carcass cuts. However, for the most part, they are carried out with animals finished in feedlots and/or with released animals, which do not represent the reality of production systems located in tropical regions because tropical forage grasses are the food base of small and large ruminants and are responsible for most of the meat produced in the tropics. Therefore, the objective was to predict the weights of the primary carcass cuts of Santa Inês lambs finished in tropical pastures through biometric measurements. Adjustments of multiple linear equations and selection of variables to predict carcass characteristics were performed using the STEPWISE option and Mallow's Cp. The biometric measurements obtained at the time of slaughter can be used as predictive variables of carcass of Santa Inês sheep finished in tropical pastures. The prediction equations are precise and accurate. The aim of this study was to predict carcass traits of Santa Inês lambs finished in tropical pastures by using biometric measurements. Data originated from two experiments involving 56 lambs (32 in experiment I and 24 in experiment II). In both experiments, the sheep were finished in that were finished in pastures of Panicum maximum and Brachiaria brizantha, experiment I being conducted in the rainy season and experiment II in the dry season. The following biometric measurements were recorded before slaughter: body length (BL), withers height (WH), rump height (RH), thorax width (TW), rump width (RW), chest width (CW), heart girth (HG), thigh circumference (TC), rump circumference (RC) and leg length (LL), in addition to live weight at slaughter (SW). After slaughter, hot carcass weight (HCW), cold carcass weight (CCW) and the weights of primal cuts (shoulder, neck, loin, leg and rib) were recorded. In the equations generated to predict SW, HCW and CCW, R2 ranged from 0.58 to 0.91 and the measurements of WH, TC, CW, HG and RW were the most relevant. In the equations developed to predict the weight of primal cuts, in turn, R2 ranged from 0.26 to 0.99. In these models, SW, BL, CW, TC, LL and HG explained most of the variation in the weight of primal cuts. Biometric measurements can be used to accurately and precisely predict HCW, CCW and the weight of primal cuts from the carcass of Santa Inês sheep finished in tropical pastures, since the equations presented R2 and correlation coefficient and agreement above 0.8. [ABSTRACT FROM AUTHOR]

Simple Summary: Livestock activity plays a crucial role in the Amazon region of Ecuador. However, the rapid expansion of extensive pastures has led to serious problems in the environment. Grasses, such as Panicum maximum, are widely used by producers in Orellana Province, but poor management practices have resulted in inefficient production systems, as evidenced by decreased yield. Our study demonstrates that in silvopastoral systems, resources are used very efficiently, and growing conditions are improved, leading to greater productive responses. Furthermore, we observed that guinea grass responded well in silvopastoral systems. Therefore, these plants should be managed through well-planned grazing to achieve a high yield and better chemical composition. Climate change has increased the interannual and seasonal variation in the average temperature and precipitation rate, which determine forage availability globally. Similar patterns of change have occurred in tropical regions, and Ecuador is no exception. This region includes other influencing factors, such as the conversion of tropical forests to extensive pastures. Therefore, this study was carried out to evaluate guinea grass (Panicum maximum) cultivated under silvopastoral systems with different management strategies in both of the seasons of the study region in Ecuador (rainy season and dry season). A randomized complete block design was used for the experiment, with three repetitions and three treatments. Agronomic measures, forage production, chemical composition, animal responses, and soil properties were evaluated. Data were analyzed with the Mixed model of SAS. Differences in all evaluated parameters were observed between treatments, and silvopastoral systems (SPSs) produced better results than conventional grass monoculture. Furthermore, there was a strong seasonal effect on forage production, chemical composition, and soil properties. Therefore, management of Panicum maximum with well-planned grazing can enhance animal responses and help to retain natural resources, lowering the pressure on forests. [ABSTRACT FROM AUTHOR]

The Brazilian territory contains approximately 160 million hectares of pastures, and it is necessary to develop techniques to automate their management and increase their production. This technical note has two objectives: First, to estimate the canopy height using unmanned aerial vehicle (UAV) photogrammetry; second, to propose an equation for the estimation of biomass of Brazilian savanna (Cerrado) pastures based on UAV canopy height. Four experimental units of Panicum maximum cv. BRS Tamani were evaluated. Herbage mass sampling, height measurements, and UAV image collection were simultaneously performed. The UAVs were flown at a height of 50 m, and images were generated with a mean ground sample distance (GSD) of approximately 1.55 cm. The forage canopy height estimated by UAVs was calculated as the difference between the digital surface model (DSM) and the digital terrain model (DTM). The R2 between ruler height and UAV height was 0.80; between biomass (kg ha−1 GB—green biomass) and ruler height, 0.81; and between biomass (kg ha−1 GB) and UAV height, 0.74. UAV photogrammetry proved to be a potential technique to estimate height and biomass in Brazilian Panicum maximum cv. BRS Tamani pastures located in the endangered Brazilian savanna (Cerrado) biome. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the residual herbage mass on the sward structure of a rotational tropical pasture (Panicum maximum Jacq), grazed by F1 Boer x Saanen goats. The area was divided into 12 paddocks of 990 m2 each, allocated in six blocks. Each paddock was divided into two identical plots (treatments, TRT) with high residual (HR) and low residual (LR) green mass (GM). Each plot was grazed for three consecutive d before animals were rotated. Sward height and herbage samples were taken in the morning on day 1, 2, 3 of grazing and on residual mass (D1, D2, D3 and D4). For each sampling, two quadrates of 50 x 50 cm were randomly cast within the plot. Herbage mass (HM) was cut down to the ground level within the quadrates, weighed, divided into three parts: green leaves mass, stem mass and dead herbage mass, and dried at 65°C. Measurements were conducted during three consecutive grazing cycles of 36 d. The HM, GM, leaf proportion and sward height decreased from D1 to R. In contrast stem:leaf ratio (S:L) increased from D1 to R (Table). Sward height was higher for HR than in LR, even though both treatments had similar HM, GM and S:L values in the first grazing day (D1) of the paddock. Our findings suggested that green leaf might be the principal component that dictates intake in tropical pastures, even when herbage allowances are low. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the grazing behaviour of F1 Boer x Saanen goats maintained in a tropical pasture (Panicum maximum Jacq), under rotational grazing system in different sward structure. The area was divided into 12 paddocks of 990 m2 each, allocated in six blocks. Each paddock was divided into two identical plots (treatments, TRT) with high residual (HR, 3.1 t/ha of green herbage mass; GHM) and low residual (LR, 2.0 t/ha GHM). Each plot was grazed for three consecutive d (D1, D2 and D3) before animals were rotated. Grazing time (GT, min) was recorded during daytime (0700 to 1900 h) and behavior was observed every 10 min, with four animals per TRT. Bite rate (BR, bites/min) was the total number of bites during three minutes, and bite mass (BM, g/bite) was estimated with esophageally fistulated animals. Measurements were conducted during three consecutive grazing cycles of 36 d. The mean stocking rate for HR was 33 goats/ha (or 6.6 animal unity (AU)/ha) and for LR was 43 goats/ha (or 8.4 AU/ha). The GT increased from D1 to D3 (468, 491 and 535 min for D1, D2, D3) in the LR, but did not differ in the HR (468 min). BR did not differ between treatments (P=0.12) or among days (P=0.42), and averaged 80.3 bites/min. In contrast, BM was higher (P=0.01) in HR (0.18 g/bite) than in LR(0.15 g/bite), and decreased from D1 to D3 (0.22; 0.16 and 0.11 g/bite). These differences can be explained by the low herbage allowances in the LR. We observed the functional relationship between BM and GT, in which the animal increased the grazing time to offset the lower BM. Our findings are consistent with the general assumption that BM are greatest during the first day, as a result of the trade-off between quantity and quality of the herbage mass. a Sponsored by FAPESP and CNPq, Brazil. [ABSTRACT FROM AUTHOR]

Sorghum is tipically used for silage, but also can be used for grazing. Hybrid sorghum is often planted for fall pasture when the quality of tropical pasture decline. The objective of this trial was to compare the milk production of crossbred cows grazing a perennial tropical pasture composed of guineagrass ( Panicum maximum) and sorghum x sudangrass(Sorghum bicolor x Sorghum sudanense ) pastures in a rotational system during the fall. Eighteen crossbred cows (Holstein x Gir), from 30 to 90 days in milk (in each experimental period) were used during two consecutives years and two grazing cycles per year. The experimental design was a split-split plot (two cycles and two years), analysed with SAS program. The three treatments were sorghum x sudangrass only (negative control), sorghum x sudangrass plus 3 kg of concentrate/hd/d, and guineagrass plus 6 kg of concentrate/hd/d. A significant (P< 0.01) diet effect was observed on milk yield. Cows fed sorghum x sudangrass plus 3 kg of concentrate and guineagrass plus 6 kg of concentrate showed higher milk production than cows fed with sorghum x sudangrass pasture. However there were no differences (P >0.10) in fat-corrected milk production. Treatments did not affect %fat, %protein, %lactose, or %total solids not fat. Year affected %fat (P<0.001). No parameters were affected by grazing cycles. The authors concluded that concentrate supplementation improves the milk production for cows grazing sorghum x sudangrass pastures. [ABSTRACT FROM AUTHOR]