PLANT RESIDUES AS AN ALTERNATIVE FOR SUBSTRATE COMPOSITION IN THE PRODUCTION OF Eucalyptus grandis SEEDLINGS

Selecting constituents for substrate formulations is of fundamental importance for the production of quality seedlings. The objective of this work was to evaluate the initial growth of Eucalyptus grandis seedlings, using carbonized and fresh coffee husks, cattle manure, coconut fiber and carbonized rice husks as substrate constituents, in different combinations. As a control treatment, the commercial substrate Maxfértil was used. The experiment was set in a nursery, in a randomized block design, consisting of eight treatments and four replications, with a sample unit of 16 seedlings. To evaluate the quality of the seedlings formed, the biometric variables, and plant biomass were quantified and the characterization of the physical and chemical properties of the formulated substrates was also carried out, regarding the characteristics of the seedlings produced. Qualitative analyses were used, where the ease of removing the seedlings from the tube and the aggregation of the roots to the substrate were assessed. After data analysis, it was found that the use of coffee husks was adequate for the production of Eucalyptus grandis seedlings for most of the analyzed variables, with higher values than the seedlings formed in the control treatment. Thus, coffee husks are indicated as an alternative constituent of substrates for the production of seedlings of the referred specie

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Desempenho e exigências de aminoácidos de bovinos Nelore e cruzados Angus × Nelore alimentados com dietas contendodiferentes teores de proteína bruta durante os estágios de crescimento e terminação

An experiment was conducted to evaluate whether a reduction in dietary crude protein and genetic group (GG) affects animal performance, feed efficiency and carcass traits of beef cattle at different stages of feedlot. Forty-four animals (22 Nellore and 22 crossbred F1 Angus x Nellore), with 8 months and initial shrunk BW (SBW) = 218.6 ± 2.15 kg (Nellore = 211.5 kg; Angus x Nellore = 225.7 kg) were used in this experiment. Eight animals (4 from each genetic group) slaughtered at the beginning of the experiment were used as baseline reference to estimate initial chemical body composition. The 36 remaining bulls were randomly assigned to one of three dietary treatments. The experiment was conducted in a completely randomized design with six replicates, in a 2x3 factorial scheme. The factors were two genetic groups (Nellore and crossbred F1 Angus x Nellore - A×N) and three crude protein contents (CP) (100, 120 and 140 g/kg DM).The experimental period lasted 224 days, being divided in 2 growing stages (GS; Growing (GR) = 112 days, and Finishing (FS) = 112 days). At the end of the experiment, all animals were slaughtered to evaluate their chemical body composition, and carcass characteristics. Crossbred A×N had a higher DMI (%BW) (19.28) compared to Nellore (18.26), and also higher ADG (A×N = 1.18; Nellore = 0.88 kg/d), regardless of growth stage or CP. Crossbred A×N had a higher intake of all nutrients regardless theCPor growth stage. Crossbred A×N ended up the experiment heavier than Nellore, since they showed a greater ADG and were more efficient when compared to Nellore animals. DMI did not differ (P> 0.05) among CP contents within growth stages, however it increased over time. Animals fed 14% CP had a lower DMI (g/BW) during growing stage, however differences were vanished on finishing stage. During growing stage, animals fed 10% CP had a lower ADG compared with animals fed 12 and 14% CP, which did not differ between them. However, during finishing stage there was no difference among CP on ADG. Differences among CP regarding efficiency were also eliminated during finishing stage. Our study found that crossbred animals have, not only greater performance, but also show better carcass traits compared to Nellore, representing an option to increase productivity. We also found that it is possible to adjust diets according to feedlot stage. During the growing stage, 12% of CP should be used, being reduced to 10% during finishing stage of feedlot, without adversely affects performance or carcass characteristics. A second trial aimed to evaluate amino acids requirements for beef cattle. It is expected to work with AA instead of CP requirements in order to provide the correct amount of essential AA to meet maintenance and production requirements. Despite the advances in determining microbial protein synthesis and AA digestibility in small intestine (Rutherfurd et al., 2016), lesser advances were done in intermediate metabolism of AA and especially in net requirements of AAs (Tedeschi et al., 2015). Furthermore, the use of crossbred animals has been increasingly, however, there is no data in the literature comparing AAs requirements between GG, or correlating efficiency with amino acids requirements. Therefore, the objective of this study was to evaluate the retention of AA in the empty body weight and also to determine net requirements of AA in purebred (Nellore) and crossbred (A×N) bulls, fed different crude protein content. Fifty-two bulls, (26 Nellore and 26 crossbred F1 Angus x Nellore) with 8 months and initial shrunk BW (SBW) = 215.0 ± 15.0 kg (Nellore = 208.0±12.78 kg; Angus x Nellore = 221.9±14.16 kg) were used in this experiment. Eight animals (4 from each genetic group) slaughtered at the beginning of the experiment were used as baseline reference to estimate initial chemical body composition. The 36 remaining bulls were randomly assigned to one of three dietary treatments. The experiment was conducted in a completely randomized design with six replicates, in a 2x3 factorial scheme. The factors were two genetic groups (Nellore and crossbred F1 Angus x Nellore - A×N) and three crude protein contents (CP) (100,120 and 140 g/kg DM).The experimental period lasted 224 days. At the end of the experiment, all animals were slaughtered to evaluate their amino acid composition in the body and also the net requirements of amino acids for gain. In the present study it is observed that some AA as lysine and phenylalanine have high correlation with muscle, however, other amino acids (e.g. methionine) have a stronger correlation with body’s composition. It is worth mentioning that this behavior is not constant among different weights, showing that more studies like this need to be conducted to determine more precisely the net requirements of amino acids.A third experiment was divided in two trials. The objective of the first trial was to the nutritional requirements of protein and energy for maintenance and weight gain and the efficiencies of use of metabolizable energy for maintenance and weight gain using the comparative slaughter technique. In the second trial, the net energy requirements for maintenance were also estimated using the heat production measured in a respirometric chamber. In trial 1, 52 animals (26 Nellore and 25 Angus × Nellore), with 8 months and initial body weight = 215.0 ± 15.08 kg (Nellore = 208.0 ± 12.78 kg; F1 Angus x Nellore = 221.9 ± 14.16 kg). The experiment was conducted in a completely randomized design with six replicates, in a 2×3 factorial scheme. The factors were two genetic groups (Nellore and cross-breed F1 Angus × Nellore - A × N) and three crude protein contents (CP, 100, 120 and 140 g / kg DM). The animals selected for voluntary consumption were randomly assigned to one of three dietary treatments. The animals in maintenance were fed with 12g DM/kg BW, with the diet of 12% CP on the DM basis. The animals assigned to the reference group were slaughtered for evaluation of initial empty body weight (EBW) and initial chemical composition of EBW. At the end of 225 days the animals were slaughtered. Trial 2 was carried out at the Federal University of Minas Gerais, where the production of heat (PC) and methane from eight animals (4 Nellor and 4 Crusaders Angus × Nellore) were measured in a respirometric chamber. Soon after, these same animals returned to the UFV, where a digestibility experiment was conducted using a 4 × 4 Latin Square. The relationship between SBW and EBW found in this study was 0.925. There was a difference (P 0.05) for NEg, and the equation was: RE = 0.0643 x EBW0.75 x EBWG0.6191. The conversion efficiencies of NEm to MEm of Nellore and crossbred animals in this experiment were, respectively, 61.1 and 62.7%. The equation obtained to estimate the net protein requirement for gain was: RP = 188.37 x EBWG - 9.39 x RE. The efficiency of use of the metabolizable protein for gain (k) was 0.3302. In trial 2, apparent digestibilities of nutrients did not differ (P> 0.05) among GG. Likewise, there was no difference for apparent digestibilities of nutrients (P> 0.05) when comparing restricted and voluntary consumption. CPI increased linearly (P 0,05) entre os PB dentro de estágios de crescimento, no entanto, aumentou ao longo do tempo. Animais alimentados com 14% PB tiveram um CMS (%PV) inferior durante a fase de crescimento, no entanto, diferenças foram desaparecendo durante aterminação. Durante fase de crescimento, os animais alimentados com 10% PB tiveram um GMD menor em comparação com os animais alimentados com 12 e 14% PC, que não diferiram entre si. No entanto, durante a terminação, não houve diferença entre PB em GMD. As diferenças entre PB em matéria de eficiência também foram eliminados durante a fase de terminação. Nosso estudo mostra que os animais mestiços têm, não só um maior desempenho, mas também apresentam melhores características de carcaça em relação ao Nelore, representando uma opção para aumentar a produtividade. Nós também acreditamos que seja possível ajustar as dietas de acordo com a fase de confinamento. Durante a fase de crescimento, 12% da PB deve ser usado, sendo reduzido para 10% durante a fase de terminação do confinamento, sem afetar o desempenho ou as características de carcaça. Um segundo experimento teve como objetivo avaliar as exigências de aminoácidos para bovinos de corte. Espera-se poder trabalhar com exigência de AA e não de PB, a fim de proporcionar a quantidade correta de AA essenciais para satisfazer os requisitos de mantenã e de produção. Apesar dos avanços na determinação de síntese de proteína microbiana edigestibilidade dos AA no intestino delgado (Rutherfurd et al., 2016), os avanços menores foram feitas no metabolismo intermediário de AA e especialmente em exigências líquidas de AAs (Tedeschi et al., 2015). Além disso, a utilização de animais cruzados tem sido cada vez mais, no entanto, não há dados na literatura comparando requisitos AAs entre GG, ou correlacionando a eficiência com as exigências de aminoácidos. Portanto, o objetivo deste estudo foi avaliar a proporção e a retenção dos AA na carcaça, bem como determinar as exigências líquidas de AA em touros Nelore e cruzados A × N, alimentado com dietas contendo diferentes níveis de proteína. Cinquenta e dois touros, (26 Nelore e 26 mestiças F1 Angus x Nelore), com 8 meses e peso corporal em jejum (PCj) inicial = 215,0 ± 15,0 kg (Nelore = 208,0 ± 12,78 kg; Angus x Nelore = 221,9 ± 14,16 kg) foram utilizados neste experimento. Oito animais (4 de cada grupo genético) foram abatidos no início do experimento, e utilizados como base de referência para estimar a composição química corporal inicial. Os 36 touros restantes foram distribuídos aleatoriamente a um dos três tratamentos. O experimento foi conduzido em delineamento inteiramente casualizado, com seis repetições, em esquema fatorial 2x3. Os fatores foram dois grupos genéticos (Nelore e cruzados F1 Angus x Nelore - A × N) e três teores de proteína bruta (PB) (100, 120 e 140 g / kg MS). O período experimental foi de 224 dias. Ao final do experimento, todos os animais foram abatidos para avaliar sua composição corporal de aminoácidos e as exigências líquidas de aminoácidos para ganho. No presente estudo, observa-se que alguns AA como lisina e fenilalanina tem alta correlação com o músculo, no entanto, outros aminoácidos (por exemplo, metionina) têm uma forte correlação com a composição do corpo. Vale ressaltar que este comportamento não é constante entre os diferentes pesos, mostrando que mais estudos como este precisam ser realizados para determinar com maior precisão as necessidades líquidas de aminoácidos para bovinos de corte. Um terceiro experimento foi conduzido com o objetivo de avaliar as exigências nutricionais de proteína e energia para mantença e ganho de peso e as eficiências de utilização da energia metabolizável para mantença e ganho de peso, usando a técnica do abate comparativo, e, ainda, estimar as exigências líquidas de energia para mantença utilizando-se a produção de calor mensurada em câmara respirométrica. Para avaliação da exigência pelo método do abate comparativo, foram utilizados 52 bovinos machos, não castrados, comida de média de 8 meses e peso médio inicial de 215,0±15,08 kg (Nelore = 208,0±12,78 kg; F1 Angus x Nelore = 221,9±14,16 kg). O experimento foi conduzido em delineamento inteiramente casualizado com seis repetições, em esquema fatorial 2x3. Os fatores foram dois grupos genéticos (Nelore e cruzado F1 Angus × Nelore - A × N) e três conteúdos de proteína bruta (PB) (100, 120 e 140 g/kg MS). Os animais selecionados para consumo voluntário foram redistribuídos aleatoriamente em três grupos que receberam uma das 3 dietas experimentais. Os animais em manteça foram alimentados com 12g de MS por kg de peso corporal, com a dieta de 12% de PB na base da MS. Os animais designados ao grupo referência foram abatidos para avaliação do peso PCVZ inicial e da composição química inicial do PCVZ. Ao final de 225 dias os animais foram abatidos.Para a avaliação em câmara respiromética,oito animais (4 Nelores e 4 cruzados Angus × Nelore) foram enviados para a Universidade Federal de Minas Gerais, onde, a produção de calor (PC) e de metano foram mensuradas. Logo após, esses mesmos 8 animais voltaram para a UFV, onde um experimento de digestibilidade foi conduzido utilizando um QL 4 × 4. A relação entre PCJ e o PCVZ encontrada neste estudo foi de 0,925. Houve diferença (P 0,05) para ELg, sendo obtida a equação: ER = 0,0643 x PCVZ0,75 x GPCVZ0,6191. As eficiências de conversão da ELm para EMm de animais Nelore e cruzados neste experimento foram, respectivamente, 61,1 e 62,7%. A equação obtida para estimar a exigência líquida de proteína para ganho foi: PR = 188,37 x GPCVZ – 9,39 x ER. A eficiência de utilização da proteína metabolizável para ganho (k) foi de 0,3302. No experimento 2, as digestibilidades aparentes dos nutrientes não diferiram (P> 0,05) entre os GG. Da mesma forma, não houve diferença para as digestibilidades aparentes dos nutrientes (P> 0,05) quando se comparou consumo restrito e voluntário. O CPB aumentou linearmente (P< 0,05) com os níveis de PB. Houve efeito linear dos níveis dietéticos de PB (P< 0,05) sobre as digestibilidades aparentes da MS e MO. Uma Elmde 85,2 kcal/PCVZ0,75/dia e uma EMm de 114 kcal/PCVZ0,75/dia foram obtidas com a utilização da câmara respirométrica, sendo esses valores superior e inferior, respectivamente, aos obtidos pelo abate comparativo.Conselho Nacional de Desenvolvimento Científico e Tecnológic

Performance and nutritional requirements of crosbreed holstein x zebu bulls fed with diets containing different protein levels

O presente trabalho foi realizado a partir de um experimento descrito na forma de dois capítulos. No capítulo 1 objetivou-se avaliar os consumos de matéria seca (CMS) e dos constituintes da dieta, o ganho médio diário (GMD), a digestibilidade aparente, e o rendimento de carcaça fria (RCF) e de cortes básicos (RCB) de bovinos machos cruzados holandês x zebu, não castrados, recebendo dois níveis de proteína (PB) na fase inicial e final do experimento. Utilizaram-se 24 animais com peso corporal inicial médio de 417±54 kg, distribuídos em delineamento inteiramente casualizado, com seis repetições, em esquema fatorial 2x2, em que os fatores foram dois níveis de PB na fase inicial do confinamento (11 ou 13% de PB, dos dias 1 a 36) e dois níveis de PB na fase final (11 ou 13% de PB, dos dias 37 a 72). As digestibilidades das dietas foram avaliadas no final de cada período experimental, utilizando-se a fibra em detergente neutro indigestível (FDNi) como indicador. Ao final do experimento, os animais foram abatidos para a determinação das características da carcaça. Os dados foram analisados utilizando-se o procedimento PROC MIXED do SAS. Não houve efeito (P>0,05) da interação entre o nível de proteína na fase inicial e final sobre os consumos de nenhum dos nutrientes avaliados. Não houve efeito (P>0,05) dos níveis de proteína nas fases inicial e final sobre o consumo de MS, matéria orgânica (MO), proteína bruta (PB), fibra em detergente neutro corrigida para cinzas e proteína (FDNcp), extrato etéreo (EE), carboidratos não fibrosos (CNF) e de nutrientes digestíveis totais (NDT). Houve efeito da interação (P0,05) sobre o GMD, os cortes comerciais agrupados ou não, e o RCF. Conclui-se que não há efeito benéfico da utilização de níveis variados de PB para terminação de bovinos e recomenda-se o nível fixo de 11% de PB. No capítulo 2 objetivou-se determinar as exigências nutricionais de energia e proteína para mantença e ganho de peso, as eficiências parciais de deposição de energia na forma de proteína (kp) e gordura (kf), e a eficiência da utilização da energia metabolizável para mantença (km) e ganho de peso (kg) de bovinos cruzados holandês x zebu em terminação. Foi realizado um experimento de abate comparativo no qual foram utilizados 32 animais não castrados, com peso médio inicial de 410±55 kg. Destes, quatro animais foram aleatoriamente selecionados para serem abatidos ao início do experimento, compondo o grupo referência. Outros quatro animais foram selecionados aleatoriamente para perfazer o grupo mantença, sendo estes alimentados na base de 12g de MS por kg de peso corporal durante todo o período experimental. Os 24 animais restantes receberam um de dois níveis de proteína na dieta (11 ou 13% de PB, com base na MS). Após 36 dias, metade dos animais alimentados com cada nível proteico foi selecionada para a reversão do nível de PB. As dietas foram compostas por 65% de silagem de milho (SM) e 35% de concentrado, na base da matéria seca (MS). Para calcular os consumos de energia foi realizado um ensaio de digestibilidade em cada período de 36 dias, cuja excreção fecal foi determinada utilizando a fibra em detergente neutro indigestível (FDNi) como indicador. Após o abate, a meia carcaça direita foi desossada para determinação da composição corporal. As exigências de energia líquida (ELm) e metabolizável (EMm) para mantença foram obtidas relacionando exponencialmente a produção de calor (PC) e o consumo de energia metabolizável, enquanto as exigências de energia para ganho (ELg) e de proteína para ganho (PLg) foram obtidas em função do peso de corpo vazio (PCVZ),usando equações alométricas. As exigências de ELm e EMm foram de 78,6 e 113,56 kcal/PCVZ0,75/dia, respectivamente. A km foi de 69,21%. As equações obtidas para ELg e PLg foram: ELg(Mcal/dia) = 0,1568 x PCVZ0,5417 e PLg (g/dia) = 0,0511 x PCVZ0,1917. A kg foi de 36,09%. As eficiências parciais foram de 17,2% e 56,8% para kp e kf, respectivamente. A energia retida na forma de proteína (ERp) foi: ERp = 1,0693 x (ER/GPCVZ)-1,5187 . Conclui-se que as exigências de ELm e EMm para bovinos cruzados holandês x zebu não castrados em terminação são de 78,6 e 113,56 kcal/PCVZ0,75/dia e que ELg e PLg podem ser obtidas pelas equações: ELg(Mcal/dia) = 0,1568 x PCVZ0,5417 e PLg (g/dia) = 0,0511 x PCVZ 0,1917.This work was prepared from a single experiment divided in two chapters. The chapter 1 objective to evaluate the dry matter intake (DMI), nutrient intake and digestibility, average daily gain (ADG), cold carcass yield (CCY) and primary cuts yield (PCY) of crossbreed holstein x zebu bulls fed with two levels of crude protein (CP) on the initial and final phases. We used 24 steers with 417±54 kg of initial body weight, distributed in a completely randomized design with six replicates in a 2x2 factorial design. The factors were two levels of CP in the early phase (11 or 13% CP, days 1-36) and two levels of CP until the end of confinement (11 or 13% CP, days 37-72). The digestibility was evaluated at the end of each experimental phase, using indigestible neutral detergent fiber (iNDF) as a internal marker. The animals were slaughtered to determine carcass composition at the end of the experiment. Data were analyzed using the MIXED procedure of SAS. There was no effect (P> 0.05) of protein levels at the early and final phases on dry matter, organic matter (OM), CP, neutral detergent fiber corrected for ash and protein (NDFap), ether extract (EE), non-fibrous carbohydrates (NFC) and total digestible nutrients (TDN) intakes. There was no effect of the interaction (P>0.05) between the CP level at early phase and CP level at final phase in any evaluated nutrient intake. There was effect (P0.05) on the ADG as well as CCY and PCY. It can be concluded that there was no benefits of using variable levels of CP in feedlot, so the fixed level of 11% CP should be recommended. The chapter 2 objective to determine the nutritional requirements of energy and protein for maintenance and body weight gain, the partial efficiencies of energy deposition as protein (kp) and fat (kf), and the efficiency of utilization of metabolizable energy for maintenance (km) and body weight gain (kg) in crossbreed holstein x zebu bulls. We conducted a comparative slaughter experiment in which 32 bulls were used, with initial body weight of 410 ± 55 kg. Four animals were randomly selected to be slaughtered at the beginning of the experiment, composing the reference group. Another four animals were randomly selected to compose the maintenance group, which were fed with 12g DM per kg of body weight throughout the experimental period. The remaining 24 animals received four treatments, constituted by two levels of crude protein (11 or 13% CP) and two feed scheme (fixed or variable). The resulting four treatments were 11-11;11-13;13-11 e13-13% of CP in DM basis. After 36 days, the half of the animals receiving each protein level was randomly selected to receive the other CP level. The diets were composed of 65% corn silage (CS) and 35% concentrate, on the dry matter basis (DM). To calculate the energy intake a digestibility trial was carried out in each period of 36 days, when fecal excretion was determined using indigestible neutral detergent fiber (iNDF) as a internal marker. After slaughter, the right half carcass was dissected for determination of body composition. The net energy requirements for maintenance (NEm) and metabolizable energy for maintenance (MEm) were obtained by an exponential relationship between heat production (HP) and metabolizable energy intake. The energy requirements for gain (NEg) and Protein requirements for gain (NPg) were obtained as a function of empty body weight (EBW) using allometric equations. The requirements NEm and MEm were 78.6 and 113.56 kcal/PCVZ0, 75/day, respectively. The km was 69%. The equations to NEg and NPg were: NEg (Mcal/day) = 0.1568 x PCVZ0, 5417 and NPg (g/day) = 0.0511 x PCVZ0, 1917. The kg was 36%. The partial efficiencies were 17.2% and 56.8% for kp and kf, respectively. The energy retained as protein (ERp) was: ERp = 1.0693 x (RE/EBW)-1.5187. It is concluded that the NEm and MEm in crossbred Holstein x Zebu bulls are 78.6 and 113.56 kcal/EBW, and NEg and NPg could be obtained by the equations: NEg (Mcal/day) = 0.1568 x PCVZ0, 5417 and NPg (g/day) = 0.0511 x PCVZ 0,1917

O Uso de adubos de liberação lenta na produção de mudas de Handroanthus impetiginosus

The species Handroanthus impetiginosus has great economic interest due to the quality of its wood. Aiming to understand and expand the knowledge about the formation of seedlings with quality of the species, was study the efficiency and adequate doses of two slow-release fertilizers in the production of seedlings of Handroanthus impetiginosus. The experiment was carried out in a randomized block design, in a factorial (2x5). Two fertilizers (SRF1 and SRF2) were taken in five doses (0, 3, 6, 9, 12 kg dm-³). Height, stem diameter, H/SD, shoot dry mass, root and total dry mass, and Dickson Quality Index were measured. For each variable, a maximum dose of technical efficiency (MDTE) was set. An analysis of variation and comparison of means was carried out using the Tukey test for the two fertilizers used and a regression analysis of the means for the doses used. All analyzes were evaluated using the R software. All variables showed positive quadratic growth. The results of the study indicate that both fertilizers are suitable for the production of seedlings of Handroanthus impetiginosus, in the MDTE of 11.65 kg dm-3 for SRF1 and 9.19 kg dm-3 for SRF2.A espécie Handroanthus impetiginosus possui grande interesse econômico devido a qualidade da sua madeira. Visando entender e ampliar os conhecimentos sobre a sua formação de mudas com qualidade da espécie, foi estudado a eficiência e as doses adequadas de dois adubos de liberação lenta na produção de mudas de Handroanthus impetiginosus. O experimento foi conduzido em delineamento em blocos casualizados, em fatorial (2x5). Foram avaliados dois adubos (SRF1 e o SRF2) em cinco doses (0, 3, 6, 9, 12 kg dm-³). Foram mensurados a altura, diâmetro de coleto, H/SD, massa seca da parte aérea, do sistema radicular e total, e o Índice de Qualidade de Dickson. Para cada variável foi calculado a dose máxima de eficiência técnica (MDTE). Realizou-se a análise de variância e a comparação de médias pelo teste Tukey para os dois adubos utilizados e análise de regressão das médias para as doses utilizadas. Todas as análises foram realizadas utilizando o software R. Todas as variáveis apresentaram crescimento quadrático positivo. Os resultados deste estudo indicam que ambos os adubos são adequados para produção de mudas de Handroanthus impetiginosus, nas MDTE de 11,65 kg dm-3 para SRF1 e 9,19 kg dm-3 para SRF2

Energy nutritional requirements for females of Nellore, Nellore × Angus and Nellore × Simmental fed on two forage: concentrate ratios

The objective of this study was to determine the energy nutritional requirements for females of Nellore, Nellore × Angus and Nellore × Simmental fed on two levels of concentrate. Sixty heifers from three genetic groups were used: 20 Nellore, 20 Nellore × Angus and 20 Nellore × Simmental. Twelve belonged to the reference group (four of each genetic group) and were slaughtered at the beginning of the experiment. Another 12 heifers (four of each genetic group) were fed on the maintenance level and 36 heifers (12 animals of each genetic group) were kept in feeding system ad libitum with 30 (six in each group) or 50% (six of each group) dry matter concentrate. Animals were randomly assigned to six treatments in a 3 × 2 factorial arrangement (three genetic groups and two diets) with six replicates per treatment. Nine more heifers were used in a parallel experiment to estimate the apparent digestibility coefficients (three from each genetic group). Net energy requirements were estimated by the equation of retained energy as a function of metabolic empty body weight (EBW0.75) and empty body weight gain (EBWg). Requirements of metabolizable and net energy were estimated for maintenance by the equation of heat production as a function of metabolizable energy intake. Using the combined equation RE (retained energy; Mcal/day) = 0.0703 × EBW.75 × EBWg1.128 to predict net energy requirements for weight gain is recommended. The requirement of metabolizable and net energy for maintenance of all groups is 70.55 and 106.53 kcal/kgEBW0.75/day, respectively. Use efficiencies of metabolizable energy for gain and maintenance are 36.41 and 66.23%, for the three genetic groups respectively

Intake, digestibility and nitrogen use efficiency in crossbred F1 Holstein × Zebu grazing cows

The objective of this study was to evaluate intake, digestibility and nitrogen (N) compounds use efficiency in F1 Holstein × Zebu grazing cows. Eighteen crossbred cows (six Holstein × Gir, six Holstein × Guzerat, and six Holstein × Nellore) were used in the experiment, constituting three experimental treatments in simple random samples, under the same feeding conditions. At the estimation of individual intake at grazing, titanium dioxide was used for estimating fecal excretion and indigestible neutral detergent fiber, in order to determine pasture intake. There was effect of the lactation period on nutrient intake, except for the intakes of dry matter (DM), organic matter (OM) and total digestible nutrients (TDN) in % of body weight (BW), as well as those of non-fibrous carbohydrates (NFC), in kg. The digestibility coefficients of crude protein (CP), neutral detergent fiber corrected for ash and protein (NDFap) and the contents of TDN varied in function of the lactation period, whereas the coefficients of digestibility of DM, ether extract (EE) and OM did not present such effect. The total milk production projected at 305 days of lactation for Holstein × Gir cows was superior in relation to Holstein × Guzerat and Holstein × Nellore cows. The excretion of urea into urine and of urea N into the milk and the plasma presented quadratic behavior in function of the lactation period. The utilization of the genetic group from Holstein × Zebu grazing cows does not cause alterations in intake, nutrient digestibility or nitrogen use efficiency; however, there is variation in function of the lactation period. Holstein × Gir cows presented greater accumulated production during lactation and persistence, followed by Holstein × Guzerat and Holstein × Nellore cows

Exigências nutricionais de vacas nelores primíparas lactantes

Objetivou-se avaliar as exigências nutricionais de proteína e energia de vacas nelores em lactação no período de 0 a 180 dias. Foram utilizadas 20 vacas primíparas com peso corporal médio ao parto de 362±25 kg. Quatro vacas foram abatidas logo após o parto e foram consideradas grupo referência. Do parto aos 90 dias, quatro vacas receberam alimentação restrita na proporção de 1,5% do peso corporal (PC), em porcentagem da matéria seca (MS), e 12 foram alimentadas à vontade. Aos 90 dias do pós-parto, foram abatidas oito vacas (quatro de cada oferta alimentar). Dos 90 aos 180 dias, quatro vacas foram realocadas para mantença (1,8% PC em MS) e quatro continuaram em consumo voluntário, sendo todas abatidas ao final do período. Os conteúdos corporais de proteína e energia foram estimados pelo equação Y = a . Xb, em que X é o peso de corpo vazio (PCVZ) e a e b os parâmetros da equação. Foram obtidas relações médias de 0,894 para PCVZ/PC e de 0,936 para ganho de PCVZ (GPCVZ)/ganho de PC (GPC). As exigências líquidas de energia para mantença (ELm) foram de 97,84 kcal/PCVZ0,75 e as de energia metabolizável para mantença (EMm), 140,17 kcal/PCVZ0,75. As eficiências de utilização da energia para mantença e ganho de peso foram 0,70 e 0,44, respectivamente. Os conteúdos corporais de proteína diminuíram com o aumento do PC, enquanto os de energia aumentaram. No leite das vacas, foram determinados teores médios de 3,71; 3,88; e 4,74%, respectivamente, de proteína bruta, gordura e lactose. A exigência de ELm para lactação de vacas nelores é de 97,84 kcal/PCVZ0,75, enquanto a de EMm é de 140,17 kcal/PCVZ0,75 e a de proteína metabolizável, de 52,8 g. Para produzir 1 kg de leite com 4% de gordura, vacas nelores necessitam de 0,300 kg de NDT

Effect of phase-feeding crude protein on performance and carcass characteristics of crossbred beef bulls: an application to reduce nitrogen compounds in beef cattle diets

Beef cattle (24) with an average initial body weight of 417 ± 54 kg were assigned in a 2 × 2 factorial design with six repetitions. The factors studied were two levels of CP: 11 (low CP) or 13 % (high CP) in the initial feedlot phase (days 1–36) and in the final phase (days 37–72). After 36 days, half of the bulls fed with each level of CP were selected to reverse the CP level. No interaction was observed (P > 0.05) between the level of protein in the initial and final phases on the intake of the nutrients evaluated. There was no effect (P > 0.05) of the protein levels in the initial and final phases on intake of dry matter, organic matter, CP, non-fiber carbohydrates, and total digestible nutrients. No differences were observed among treatments (P > 0.05) for average daily gain (X = 1.99 kg/day) and carcass traits. We conclude that it is possible to feed Holstein-Zebu crossed bulls with an average daily gain of approximately 2 kg using a fixed level of 11 % CP during the entire feedlot period, and this diet is economically viable and environmentally sound