Roberto Augusto de Almeida Torres Júnior
Bio: Roberto Augusto de Almeida Torres Júnior is an academic researcher from Empresa Brasileira de Pesquisa Agropecuária. The author has contributed to research in topics: Heritability & Beef cattle. The author has an hindex of 11, co-authored 30 publications receiving 581 citations.
TL;DR: Structural characteristics and herbage accumulation of Tanzania grass pastures under rotationally grazing and accumulation of stem material increased substantially after 95% LI, indicating the importance of grazing frequency as a means of controlling sward structure and composition.
Abstract: The objective of this work was to evaluate the structural characteristics and herbage accumulation of Tanzania grass pastures (Panicum maximum cv. Tanzania) under rotationally grazing, in an Oxisol, in experiment carried out at Campo Grande, MS. Treatments corresponded to combinations of three pre and two post-grazing conditions, and were allocated to experimental units according to a complete randomized block design, with three replications and a 3x2 factorial arrangement. The pre-grazing conditions of 90, 95 and 100% light interception (LI) were achieved consistently with swards heights around 60, 70 and 85 cm, respectively. Grazings at 90% LI resulted in larger number of grazing cycles than grazings at 95 and 100% LI. Total herbage accumulation was larger with grazings at 95% than at 90 and 100% LI, but there was no difference between the 90 and 95% LI treatments for leaf accumulation. Accumulation of stem material increased substantially after 95% LI, indicating the importance of grazing frequency as a means of controlling sward structure and composition.
TL;DR: Genomic regions and genes that play roles in birth weight, weaning weight, and long-yearling weight adjusted for 420 days of age (LYW) in Canchim cattle are identified and new candidate regions for body weight traits were detected.
Abstract: Studies are being conducted on the applicability of genomic data to improve the accuracy of the selection process in livestock, and genome-wide association studies (GWAS) provide valuable information to enhance the understanding on the genetics of complex traits. The aim of this study was to identify genomic regions and genes that play roles in birth weight (BW), weaning weight adjusted for 210 days of age (WW), and long-yearling weight adjusted for 420 days of age (LYW) in Canchim cattle. GWAS were performed by means of the Generalized Quasi-Likelihood Score (GQLS) method using genotypes from the BovineHD BeadChip and estimated breeding values for BW, WW, and LYW. Data consisted of 285 animals from the Canchim breed and 114 from the MA genetic group (derived from crossings between Charolais sires and ½ Canchim + ½ Zebu dams). After applying a false discovery rate correction at a 10% significance level, a total of 4, 12, and 10 SNPs were significantly associated with BW, WW, and LYW, respectively. These SNPs were surveyed to their corresponding genes or to surrounding genes within a distance of 250 kb. The genes DPP6 (dipeptidyl-peptidase 6) and CLEC3B (C-type lectin domain family 3 member B) were highlighted, considering its functions on the development of the brain and skeletal system, respectively. The GQLS method identified regions on chromosome associated with birth weight, weaning weight, and long-yearling weight in Canchim and MA animals. New candidate regions for body weight traits were detected and some of them have interesting biological functions, of which most have not been previously reported. The observation of QTL reports for body weight traits, covering areas surrounding the genes (SNPs) herein identified provides more evidence for these associations. Future studies targeting these areas could provide further knowledge to uncover the genetic architecture underlying growth traits in Canchim cattle.
TL;DR: Post-grazing residues of Tanzania guineagrass under rotational stocking management may be set at either 25 or 50 cm, since the herbage intake was not affected within this grazing intensity range, however, herbage removal and grazing efficiency were reduced with the 50 cm post-Grazing height and grazing time increased with long occupation periods.
Abstract: The objective of this experiment was to evaluate the ingestive behaviour, herbage intake and grazing efficiency of beef cattle steers grazing on Panicum maximum Jacq. cv. Tanzania subjected to different rotational stocking intensities. Treatments corresponded to two post-grazing conditions (residues of 25 and 50 cm) associated with a pre-grazing condition of 95% sward canopy light interception during regrowth (LI). The grazing time increased linearly with the duration of the occupation period (475 to 630 minutes/day). On paddocks grazed down to a residue of 25 cm, the bite rate increased linearly along the occupation period, with an average of 42.5 bites/minute. On paddocks grazed down to a residue of 50 cm, the bite rate was stable and equal to 39 bites/minute. There was no difference in herbage intake between grazing intensities. However, grazing at 25 cm residue resulted in greater herbage removal (68.0 vs. 45.6%) and greater grazing efficiency (90.4 vs. 49.8%) than grazing at 50 cm residue. Post-grazing residues of Tanzania guineagrass under rotational stocking management may be set at either 25 or 50 cm, since the herbage intake was not affected within this grazing intensity range. However, herbage removal and grazing efficiency were reduced with the 50 cm post-grazing height and grazing time increased with long occupation periods.
TL;DR: O experimento foi realizado para avaliar o valor nutritivo da forragem, o desempenho e a conversao alimentar de novilhos em pastos de Panicum maximum Jacq, donde o residuo de 50 cm promove maior ganho individual e maior numero of ciclos de pastejo.
Abstract: O experimento foi realizado para avaliar o valor nutritivo da forragem, o desempenho e a conversao alimentar de novilhos em pastos de Panicum maximum Jacq. cv. Tanzânia submetidos a duas intensidades de pastejo rotativo (residuos de 25 e 50 cm), associadas a intervalo de pastejo correspondente ao tempo necessario para que o dossel forrageiro interceptasse 95% da luz incidente durante a rebrotacao. O delineamento experimental utilizado foi o de blocos completos casualizados, com duas repeticoes. Foram avaliados a altura do dossel pre-pastejo, os intervalos de pastejo, o ganho de peso individual, a conversao alimentar, a taxa de lotacao e o ganho de peso por unidade de area. Pastos manejados com o residuo 50 cm apresentaram maior numero de ciclos de pastejo em relacao aqueles manejados com residuo de 25 cm. O maior ganho de peso medio diario foi registrado nos pastos manejados com 50 cm de residuo (801 g/dia) em relacao aqueles manejados com de 25 cm de residuo (664 g/dia). Em contrapartida, a taxa de lotacao foi mais alta nos pastos manejados com o residuo 25 cm, fazendo com que os ganhos de peso por unidade de area fossem 601 e 559 kg/ha para os residuos de 25 e 50 cm, respectivamente. O manejo do pasto visando altura de residuo de 25 cm proporciona maiores ganhos de peso por unidade de area e maior uniformidade de producao e o residuo de 50 cm promove maior ganho individual e maior numero de ciclos de pastejo.
TL;DR: Calving order quadratically affected pregnancy rate (PR) in this trial; PR of CO1 cows was 69% while that of cows from CO5 to CO8 was 90% followed by a gradual decline until 80% PR in C012 cows; body condition score at weaning also affected PR.
Abstract: The objective of this trial was to evaluate the effects of calving order (CO) and body condition score (BCS), scale 1(thin) to 5 (fat), on reproductive performance of 468 Nellore cows (391 multiparous and 77 primiparous) grazing Brachiaria decumbens Stapf at Brazilian Central West (Cerrados region) during four breeding seasons (from 11/1 to 1/31 of the following year). Calving order quadratically affected pregnancy rate (PR) in this trial; PR of CO1 cows was 69% while that of cows from CO5 to CO8 was 90% followed by a gradual decline until 80% PR in C012 cows. Body condition score at weaning also affected PR. For instance, CO1 cows with BCS of 2.0 and 3.5 had 52.7 and 82.5% of PR, respectively. Cows from CO4 to CO8 and BCS of 3.5 showed 96% of PR. CO1 cows that calved late in the season had 37.7% of PR but independent of CO, cows that calved earlier in the calving season had PR greater than 80%. CO1 cows calved 350.12 days after the start of the mating season while multiparous cows calved earlier (328.32 days). CO1 had the longest calving interval (CI) averaging 392.10 days whereas that from CO5 to CO9 cows averaged 365 days. Calving interval was affected by year, CO, number of days spent to calve in the calving season, and body weight change in the mating season. In addition, cows body weight (BWW) and BC at weaning (BCW) were both affected by CO and year. Body weight of calves at weaning increased from CO1 to CO4/CO5 averaging 159 kg for calves from CO1 cows and 169 kg when all CO levels were included. High production and reproductive performance are obtained from CO3 to CO8 and BCS above 3.0 and 3.5 for multiparous and primiparous Nellore cows, respectively.
28 Sep 2014
TL;DR: A critical appraisal is given of the need for revision and change of paradigms as a means of improving and consolidating the knowledge on animal production from pastures, which idealizes efficient, sound and sustainable grazing management practices necessary to realize the existing potential for animal production in the tropics.
Abstract: Grazing management has been the focus of the research with forage plants in Brazil for many years. Only in the last two decades, however, significant changes and advances have occurred regarding the understanding of the key factors and processes that determine adequate use of tropical forage plants in pastures. The objective of this review is to provide an historical overview of the research with forage plants and grasslands in Brazil, highlighting advances, trends, and results, as well as to describe the current state of the art and identify future perspectives and challenges. The information is presented in a systematic manner, favoring an integrated view of the different trends and research philosophies. A critical appraisal is given of the need for revision and change of paradigms as a means of improving and consolidating the knowledge on animal production from pastures. Such analysis idealizes efficient, sound and sustainable grazing management practices necessary to realize the existing potential for animal production in the tropics.
TL;DR: The endoplasmic reticulum (ER) is a critical organelle for normal cell function and homeostasis and the activation of unfolded protein response (UPR) that encompasses a complex network of intracellular signaling pathways.
Abstract: The endoplasmic reticulum (ER) is a critical organelle for normal cell function and homeostasis. Disturbance in the protein folding process in the ER, termed ER stress, leads to the activation of unfolded protein response (UPR) that encompasses a complex network of intracellular signaling pathways. The UPR can either restore ER homeostasis or activate pro-apoptotic pathways depending on the type of insults, intensity and duration of the stress, and cell types. ER stress and the UPR have recently been linked to inflammation in a variety of human pathologies including autoimmune, infectious, neurodegenerative, and metabolic disorders. In the cell, ER stress and inflammatory signaling share extensive regulators and effectors in a broad spectrum of biological processes. In spite of different etiologies, the two signaling pathways have been shown to form a vicious cycle in exacerbating cellular dysfunction and causing apoptosis in many cells and tissues. However, the interaction between ER stress and inflammation in many of these diseases remains poorly understood. Further understanding of the biochemistry, cell biology, and physiology may enable the development of novel therapies that spontaneously target these pathogenic pathways.
TL;DR: Grazing management should aim for low herbage mass during the transition period from winter to spring in order to allow fast recovery of swards and favour herbage accumulation during the following growing season.
Abstract: Grazing strategies promote changes in sward structure that can affect patterns of herbage accumulation and sward flexibility to management. This experiment evaluated sward structural characteristics and herbage accumulation of Mombaca guinea grass (Panicum maximum Jacq. cv. Mombaca) subjected to rotational stocking managements. Treatments involved grazing when swards reached either 95 or 100% interception of the incident light (LI), to post-grazing heights of 30 and 50 cm, and were allocated to 2,000 m2 paddocks according to a randomised complete block design in a 2 × 2 factorial arrangement with four replications, from January 2001 to February 2002. Sward canopy changed from a vertical to a more horizontal orientation as the light interception area index and height increased from post to pre-grazing. Leaf canopy height pre-grazing was stable throughout the year and around 90 and 115 cm for the 95% and 100% LI treatments respectively, indicating a potential for development and use of target-based grazing management practices. Herbage mass pre and post-grazing was lower for the 95% than the 100% LI treatments, but with higher proportion of leaf and lower proportions of stem and dead material. Treatment effects on herbage accumulation were cumulative and became more evident as the experiment progressed, with up to 6 t ha-1 DM advantage to the 95/30 treatment. Although based on a single year experiment, grazing management should aim for low herbage mass during the transition period from winter to spring in order to allow fast recovery of swards and favour herbage accumulation during the following growing season.
TL;DR: Results obtidos indicam that, durante o rebaixamento do dossel, pastejos mais frequentes e menos severos proporcionam aos animais a obtencao de dietas com elevada proporcoes de lâminas foliares, o that deve aumentar o valor nutritivo da forragem consumida.
Abstract: O objetivo deste trabalho foi avaliar o efeito de estrategias de pastejo rotativo sobre a composicao morfologica da forragem consumida por bovinos de corte em pastos de Brachiaria brizantha cv. Marandu. Os pastejos foram realizados sempre que o dossel atingia 95 ou 100% de intercepcao luminosa (IL) ate as alturas pos-pastejo de 10 e 15 cm. Foi avaliada a composicao morfologica das extrusas coletadas de animais fistulados no esofago em tres etapas ao longo do rebaixamento dos pastos. A medida que o rebaixamento progrediu, a proporcao de lâminas foliares na extrusa diminuiu e a de colmos e de material morto aumentou. Pastejos iniciados com 100% de IL ou realizados ate a altura pos-pastejo de 10 cm resultaram em menor proporcao de lâminas foliares e maior de colmos e de material morto. O tratamento 95/15 foi consistente entre os tratamentos que apresentaram as maiores proporcoes de lâminas foliares e menores de colmos e de material e, mesmo no final do rebaixamento, apresentou, ainda, mais de 50% de proporcao de lâminas foliares na extrusa. Os resultados obtidos indicam que, durante o rebaixamento do dossel, pastejos mais frequentes e menos severos proporcionam aos animais a obtencao de dietas com elevada proporcao de lâminas foliares, o que deve aumentar o valor nutritivo da forragem consumida.