Forage Intake of \u3ci\u3eNellore\u3c/i\u3e Steers Grazing a \u3ci\u3eCajanus Cajan\u3c/i\u3eLegume-Grass Intercropped Pasture

This study evaluated forage, supplement, and total (forage + supplement) dry matter intake (DMI, expressed as kg/day and as percentage of average live weight, %ALW) of Nellore steers in different production systems, including a Cajanus cajan (Pigeon pea) legume-grass intercropped pasture by using external (titanium dioxide, TiO2) and internal (indigestible neutral detergent fiber, iNDF) markers. The experiment was carried out at Embrapa Southeast Livestock, São Carlos, SP, Brazil, in the rainy (January) and dry (July) seasons of 2021. Eighteen animals Nellore steers were randomly distributed into three treatments with three replications (1.5 ha paddocks each): 1) degraded pasture of Urochloa decumbens cv. Basilisk (DEG); 2) Intercropped legume-grass pasture composed by U. decumbens cv. Basilisk, U. brizantha cv. Marandu and Cajanus cajan cv. BRS Mandarin limed and fertilized with P, K, S, micronutrients (INT) and 3) mixture pasture of U. decumbens cv. Basilisk and U. brizantha cv. Marandu limed and fertilized with P, K, S, micronutrients and 200 kg N-urea ha-1 year-1 (REC). The statistical model considered treatment and season as fixed effects, and the treatment×season interaction was tested. Data were submitted to analysis of variance (PROC MIXED) and means were compared by the Fisher test at 5%. Significant treatment×season interaction was found (P \u3c 0.05). During the rainy season lower values of forage and total DMI were found for the INT treatment when compared to REC. However, during the dry season, the treatment with Pigeon pea inclusion (INT) presented higher values of forage and total DMI. The DEG and REC system steers reduced their DMI from the rainy season to the dry season, even receiving a mineral energetic-protein supplement with urea, while the INT steers maintained DMI between seasons without receiving the energetic-protein supplement. These results highlight the potential of including Pigeon pea in pasture-based systems, especially during the dry season when tropical grasses present low nutritional quality and forage availability

Performance of Finishing Nellore Beef Steers in Intensively Managed Pastures and Silvopastoral Systems in Southeast of Brazil

This study evaluated the average daily weight gain (ADG), stocking rates, and live weight gain per hectare (LWG) in different intensified animal production systems. The experiment was carried out from September 2020 to September 2021 at Embrapa Southeast Livestock, São Carlos, SP, Brazil. Thirty Nellore steers (285±21 kg of live weight and 12±13 months old) were randomly distributed into five treatments, with two replicates: 1) intensively managed and irrigated Megathyrsus maximus cv. Tanzânia pasture overseeded in the dry season with Avena byzantina and Lolium multiflorum (IHS); 2) intensively managed rainfed M. maximus cv. Tanzânia pasture (RHS); 3) intensively managed rainfed pasture with a mix of Urochloa decumbens cv. Basilisk and U. brizantha cv. Marandu (RMS); 4) intensively managed silvopastoral system with U. decumbens cv. Basilisk and Brazilian native trees (312 trees ha-1) (LFS); and 5) extensively managed degraded pasture of U. brizantha cv. Marandu and U. decumbens cv. Basilisk (DP). Data were submitted to analysis of variance considering treatments and seasons as fixed effects, and the interaction between treatment×season was tested. Means were compared by the Fisher test at 5% using the PROC MIXED of SAS. For all parameters, significant interaction was found (P\u3c .0001). In general, higher ADG, stocking rate and LWG values were found for IHS (0.82 kg d-1, 6.03 AU ha-1 and 459.9 kg ha-1, respectively), while the lowest values were found for DP (0.33 kg d-1); for LFS (1.16 AU ha-1); and for LFS and DP (71.0 and 68.9 kg ha-1, respectively). It is important to consider that for LFS the competition for natural resources between the system components (pasture and trees) together with low temperatures and soil moisture during the autumn and winter seasons may explain the unexpected low performances. Overall, our results showed that more intensified systems allowed better animal performances when compared to DP

Influence of liming and boron on development of young Swietenia macrophylla plants grown in Yellow Oxisol.

The aim of this study was to evaluate the development of young Swietenia macrophylla plants grown in Yellow Oxisol submitted to different liming and boron doses. Experimental design was completely randomized in factorial arrangement (|4x4|+1), with additional treatment (control), being 4 liming levels (0.5, 1.0, 1.5 and 2.0 t ha-1) combined with 4 boron levels (1, 2, 3 and 4 mg kg-1 of substrate). Parameters evaluated were plant height, stem diameter, stem dry matter, aerial part dry matter, root dry matter and aerial part dry matter/root dry matter ratio. The height of young Swietenia macrophylla plants was not influenced by liming and boron levels. Maximum yields of leaves and aerial part were obtained with doses of 1.57 and 1.44 t ha-1 of liming, respectively. The increase of boron levels negatively influenced the production of root dry matter. For the diameter and dry matter of stem and root significant interaction between liming and boron levels were observed. The better results linked to development of young Swietenia macrophylla plants were found at a dose of 1.5 t ha-1 of liming and 1.0 mg kg-1 of boron

Bringing together Brazilian soil scientists to share soil data.

Brazilian soil scientists have recently created a soil data repository using community-built standards and following open data policies in an attempt to address the issues mentioned above. The Free Brazilian Repository for Open Soil Data - febr -, accessible through www.ufsm.br/febr, is a centralized repository targeted at storing open soil data and serving it in a standardized and harmonized format, for various applications. This paper describes the features of febr and the opportunities that it creates for soil science.Na publicação: Wenceslau Teixeira

Chagas Cardiomyopathy Manifestations and Trypanosoma cruzi Genotypes Circulating in Chronic Chagasic Patients

Chagas disease caused by Trypanosoma cruzi is a complex disease that is endemic and an important problem in public health in Latin America. The T. cruzi parasite is classified into six discrete taxonomic units (DTUs) based on the recently proposed nomenclature (TcI, TcII, TcIII, TcIV, TcV and TcVI). The discovery of genetic variability within TcI showed the presence of five genotypes (Ia, Ib, Ic, Id and Ie) related to the transmission cycle of Chagas disease. In Colombia, TcI is more prevalent but TcII has also been reported, as has mixed infection by both TcI and TcII in the same Chagasic patient. The objectives of this study were to determine the T. cruzi DTUs that are circulating in Colombian chronic Chagasic patients and to obtain more information about the molecular epidemiology of Chagas disease in Colombia. We also assessed the presence of electrocardiographic, radiologic and echocardiographic abnormalities with the purpose of correlating T. cruzi genetic variability and cardiac disease. Molecular characterization was performed in Colombian adult chronic Chagasic patients based on the intergenic region of the mini-exon gene, the 24Sα and 18S regions of rDNA and the variable region of satellite DNA, whereby the presence of T.cruzi I, II, III and IV was detected. In our population, mixed infections also occurred, with TcI-TcII, TcI-TcIII and TcI-TcIV, as well as the existence of the TcI genotypes showing the presence of genotypes Ia and Id. Patients infected with TcI demonstrated a higher prevalence of cardiac alterations than those infected with TcII. These results corroborate the predominance of TcI in Colombia and show the first report of TcIII and TcIV in Colombian Chagasic patients. Findings also indicate that Chagas cardiomyopathy manifestations are more correlated with TcI than with TcII in Colombia

Boosting predictive ability of tropical maize hybrids via genotype-by-environment interaction under multivariate GBLUP models.

Genomic selection has been implemented in several plant and animal breeding programs and it has proven to improve efficiency and maximize genetic gains. Phenotypic data of grain yield was measured in 147 maize (Zea mays L.) singlecross hybrids at 12 environments. Single-cross hybrids genotypes were inferred based on their parents (inbred lines) via single nucleotide polymorphism (SNP) markers obtained from genotyping-by-sequencing (GBS). Factor analytic multiplicative genomic best linear unbiased prediction (GBLUP) models, in the framework of multienvironment trials, were used to predict grain yield performance of unobserved tropical maize single-cross hybrids. Predictions were performed for two situations: untested hybrids (CV1), and hybrids evaluated in some environments but missing in others (CV2). Models that borrowed information across individuals through genomic relationships and within individuals across environments presented higher predictive accuracy than those models that ignored it. For these models, predictive accuracies were up to 0.4 until eight environments were considered as missing for the validation set, which represents 67% of missing data for a given hybrid. These results highlight the importance of including genotype-by-environment interactions and genomic relationship information for boosting predictions of tropical maize single-cross hybrids for grain yield