Resumo em Português:

Foram avaliados o desempenho e a composição muscular da carcaça de alevinos de tambatinga, com peso inicial de 6,521 ± 0,300 g, alimentados com dietas isoenergéticas, isocálcicas e isofosfóricas contendo 40, 37, 34, 31 ou 28% de proteína bruta. Os peixes foram mantidos durante 40 dias em tanques de polietileno, com sistema de recirculação de água. No início e final do experimento, os peixes foram pesados e os dados utilizados para avaliação do ganho de peso diário, consumo diário de ração, conversão alimentar aparente, índice de conversão alimentar, consumo diário de proteína, taxa de crescimento específico e taxa de eficiência proteica. No início e final do experimento, foram selecionadas amostras de peixes para análise da composição muscular, e os resultados utilizados para avaliar a eficiência de retenção de proteína e a proporção de proteína e extrato etéreo no ganho de peso. Entre os parâmetros de desempenho, os níveis de PB influenciaram apenas o consumo de proteína e a taxa de eficiência proteica, com efeito linear. Os teores de proteína bruta, a proporção de proteína no ganho de peso e eficiência de retenção de proteína no músculo dos alevinos de tambatinga aumentaram linearmente com a redução de proteína bruta na dieta, enquanto o teor de extrato etéreo e sua proporção no ganho de peso diminuíram. O nível de 28% de PB, quando há suplementação com aminoácidos, pode ser utilizado em dietas para alimentação dos alevinos de tambatinga, pois não prejudica seu desempenho.

Resumo em Inglês:

This study was developed to evaluate the performance and carcass composition of tambatinga fingerlings, with initial weight of 6.521 ± 0.300 g, fed with isocaloric, isocalcic and isophosphoric diets (40, 37, 34, 31 and 28% of CP). Fish were cultivated for forty days in polyethylene tanks, with water recirculation system. Fishes were weighed at the beginning and at the end of the trial and the data were used for evaluation of weight gain, feed intake, apparent feed conversion, index of feed conversion, protein intake, specific growth rate and protein efficiency rate. At the beginning and end of the experiment, samples of fishes were selected for analysis of muscle composition, and the results were utilized to assess protein retention efficiency and proportion of protein and ethereal extract at weight gain. Among the performance parameters, crude protein levels influenced only protein intake and protein efficiency rate, with linear effect. Crude protein amount, proportion protein on weight gain and protein retention efficiency of the tambatinga fingerling's muscle, increased linearly with protein reduction in the diet, whereas ethereal extract and its proportion on weight gain decreased. It was concluded that the diet with 28% of protein can be used for tambatinga fingerlings without affecting performance.

Resumo em Português:

Este estudo foi realizado com o objetivo de investigar o efeito estimulante de cinco aminoácidos (alanina, arginina, glicina, histidina e lisina) da betaína e de suas misturas sobre a taxa de ingestão de dieta microencapsulada durante o desenvolvimento larval de pacu Piaractus mesopotamicus. Os resultados da análise estatística comprovaram a existência de efeito significativo, tanto da idade das larvas como dos aminoácidos, sobre a taxa de ingestão. No entanto, não houve significância estatística para a interação dos dois fatores. A glicina, a lisina e a betaína foram considerados bons estimuladores do comportamento alimentar de larvas de pacu.

Resumo em Inglês:

The present study aimed to investigate the stimulant effect of five amino acids (alanine, arginine, glycine, histidine and lysine) from betaine and their mixtures on the ingestion rates of formulated diet during the larval development of pacu Piaractus mesopotamicus. The statistical results showed significant effect of age and treatment. However, no significant effect was observed for the interaction of both factors. Glycine, lysine and betaine are considered good stimulants of the pacu feeding behavior.

Resumo em Português:

A fixação biológica de nitrogênio foi avaliada em jureminha (Desmanthus pernambucanus), orelha-de-onça (Macroptilium martii) e feijão-de-rolinha (Macroptilium lathyroides) cultivados em solos do semiárido da Paraíba, em vasos sem e com esterco bovino. Foram determinados o número e a biomassa de nódulos, os teores e as proporções de nitrogênio (N) fixado (percentual de nitrogênio da planta derivado do ar-%Ndda), pelo método da abundância natural, utilizando-se o capim-buffel como planta controle. As leguminosas tiveram nodulação abundante, nos três solos e na ausência ou presença de esterco, salvo quando cultivadas em Neossolo Flúvico sem adubação. A adubação com esterco aumentou o número e a biomassa de nódulos. A fixação biológica de nitrogênio foi alta nas três espécies, nos três solos: na maioria das plantas, os valores superaram 50%, chegando a 85%. Esses dados permitem estimar a capacidade de fixação das espécies no campo em 10 a 30 kg ha-1 de N, considerando as densidades de plantio e produtividade usuais. As menores %Ndda e quantidades fixadas foram encontradas nas plantas cultivadas em Neossolo Regolítico e aumentaram com a adição de esterco. Entre as espécies testadas, a fixação biológica de nitrogênio foi menos importante para D. pernambucanus. Nenhum dos parâmetros de nodulação avaliados (número, biomassa e biomassa/nódulo) explicou as proporções nem as quantidades de nitrogênio fixadas pelas plantas.

Resumo em Inglês:

The biological nitrogen fixation (BNF) of Desmanthus pernambucanus (pigeon bundleflower), Macroptilium martii and M. lathyroides (wild bushbean), grown in soils from the semiarid region of Paraíba, manured or not, was evaluated in a pot experiment. Nodule number and biomass, N content and the proportions of fixed N (%Ndfa) were estimated, using the natural abundance methodology and buffel grass as a reference plant. The legume plants nodulated abundantly in all three soils, manured or not, except when grown in Fluvic Neosol without manure. The number and biomass of the nodules increased with manure. The BNF was high in all three species and soils: in most of the plants resulting in %Ndfa above 50% and reaching 85%. Using these data, a rough estimate of the fixation capacity of these species in the field indicates amounts of 10 to 30 kg ha-1 of N, taking planting and yielding usual densities. The lowest %Ndfa and fixed quantities were obtained in plants growing in the Regolithic Neosol and they increased with manure application. Among the species, BNF was least important to D. pernambucanus. Neither the proportion nor the fixed quantities were explained by any of the nodule variables measured (number, biomass or biomass/nodule).

Resumo em Inglês:

The objective of this study was to evaluate gas exchange in the massai grass during establishment and regrowth cycles in a greenhouse, using five nitrogen (N) fertilization levels. A completely randomized split-plot design of five nitrogen levels (0; 150; 300; 450 and 600 mg N•dm-3 of soil) was employed with the N levels as plots, and the cycles (establishment, regrowth 1 and 2) as subplots, evaluated with five replicates. We evaluated leaf transpiration (E), leaf temperature (TFOL), leaf photosynthesis rate (A), leaf carbon dioxide concentration (Ci), stomatal conductance (gs), photosynthesis/transpiration ratio (A/E), photosynthesis/conductance ratio (A/gs), chlorophyll relative index (CRI), and nitrogen sufficiency index (NSI). Growth cycles influenced all physiological characteristics, except for NSI. N fertilization levels affected TFOL, A, CRI and NSI variables, whereas for gs, E, Ci, A/E and A/gs it did not occur. A increased from 6.38 to 10.33 µmol•m-2.s-1, at levels 0 and 600 mg N•dm-3 of soil, respectively. Gas exchange in the massai grass was favored by nitrogen fertilization, since the cycles amended these characteristics of the grass.

Resumo em Português:

Objetivou-se avaliar características morfogênicas e estruturais do capim-tifton 85 adubado com nitrogênio nas doses de 0, 33, 66, 100 ou 133 kg/ha.ano em três alturas à data de corte (30, 40 ou 50 cm). O delineamento foi inteiramente casualizado em esquema de parcelas subdivididas com três repetições. As doses de nitrogênio (N) corresponderam às parcelas e as alturas ao tempo de corte, às subparcelas. A taxa de aparecimento foliar do capim-tifton 85 foi influenciada de forma negativa pela altura da planta na época do corte e de maneira positiva pela dose de nitrogênio. A taxa de senescência foliar e o número total de folhas por perfilho diminuíram, enquanto a taxa de alongamento foliar aumentou com a adubação nitrogenada. Por outro lado, a taxa de senescência foliar e o número total de folhas por perfilho aumentaram com a altura das plantas na época da colheita. Já o número de folhas vivas por perfilho não foi influenciado pela dose de nitrogênio nem pela altura da planta na época do corte. Para uma mesma altura do capim-tifton 85 na época da colheita, a adubação nitrogenada aumenta o fluxo de tecidos e a frequência de desfolhação. Na condição de desfolhação intermitente, o capim-tifton 85 deve ser colhido com altura de até 30 cm.

Resumo em Inglês:

The objective of this study was to evaluate the morphogenic and structural characteristics of tifton 85 bermudagrass under different nitrogen doses (0, 33, 66, 100 or 133 kg/ha.year of N) and three different plant heights (30, 40 or 50 cm) at harvesting time. A split plot scheme in a completely randomized design with three replications was used. The nitrogen (N) doses stood for the portions and the haversting heights, for the subportions. The leaf appearance rate of tifton 85 bermudagrass was negatively influenced by plant height at harvesting time, but positively influenced by N dose. Leaf senescence rate and total number of leaves per tiller decreased, whereas leaf elongation rate increased with nitrogen fertilization. On the other hand, leaf senescence rates and total leaf number per tiller increased according to the plant height at harvesting time. Contrarily, the number of green leaf per tiller was not influenced by N dose or plant height at harvesting time. For the same height of 'tifton 85' bermudagrass at harvesting time, nitrogen fertilization increases tissues flux and defoliation frequency. Under intermittent defoliation conditions, 'tifton 85' bermudagrass should be harvested at 30 cm of height.

Resumo em Português:

O objetivo neste trabalho foi selecionar genótipos mais produtivos e persistentes de trevo-branco (Trifolium repens L.) por meio da avaliação agronômica de suas progênies. Foi avaliada a produção de matéria seca (MS) de 22 progênies comparadas à população UFRGS-2004-2 e à cultivar Jacuí de trevo-branco consorciadas com azevém (Lolium multiflorum Lam.) durante os anos de 2008 e 2009. A média de produção de MS de trevo-branco durante os dois anos foi de 3.671 e 2.107 kg/ha em Eldorado do Sul e Bagé, respectivamente. Em Eldorado do Sul e Bagé, a cultivar Jacuí com mais 13 progênies formaram os grupos com maior produção. Sete progênies ficaram no grupo "a" em ambos os locais, enquanto somente a população UFRGS e uma progênie apresentaram menores produções nos dois locais, havendo interação genótipo × ambiente. As progênies 2, 6 e 7 oriundas de Bagé e 22 (Etiópia), 23 (Portugal), 24 (Estados Unidos) e 30 (Irlanda) podem ser utilizadas na formação de uma cultivar sintética mais produtiva e persistente as condições do verão.

Resumo em Inglês:

The aim of this work was to select higher yielding and persistent genotypes, evaluating their progenies agronomically. The DM yield of 22 progenies compared with the population of UFRGS-2004-2 and with the Jacuí cultivar of white clover mixed with ryegrass (Lolium multiflorum Lam.), during the years 2008 and 2009 was evaluated. The average DM yield of white clover during the two years was 3671 and 2107 kg/ha, in Eldorado do Sul and Bagé, respectively. In Eldorado do Sul and Bagé the Jacuí cultivar with thirteen more progenies formed groups with higher production. Seven progenies were in the group "a" in both places, whereas only the population of UFRGS and one progeny had lower production in both sites, with genotype × environment interaction. Progenies 2, 6 and 7 from Bage and 22 (Ethiopia), 23 (Portugal), 24 (United States) and 30 (Ireland), can be utilized in the creation of a more productive and synthetic cultivar, in addition to being more resistant to summer conditions.

Resumo em Inglês:

The objective of this study was to evaluate the agronomic divergence of 25 sorghum hybrids (Sorghum bicolor L. Moench) in the semiarid region of Paraiba. A randomized block design with three replications was used for evaluation of plant height (PH), total natural matter production (TNMP) and total dry matter production (TDMP) and the percentage of components of DM (panicle, leaf blade, stem and dead matter) of the following hybrids: 866005, 866019, 866033, 866034, 866035, 866036, 866037, 866040, 866041, 866042, 866043, 866044, 870025, 870031, 870035, 870041, 870051, 870067, 870081, 870085, 870095, 1F305, BRS 610, Volumax, and XBS60329. Hybrid 1F305, followed by hybrid 866034, presented the highest average PH. There was a range from 7.679 to 20.948 kg/ha (average of 13,799 kg/ha) for TDMP. Hybrids 1F305, BRS 610 and Volumax presented less potential, and hybrids 866,041 and 866,042 were the most productive. Based on cluster analysis and subjective cut in 50% of dissimilarity, it was possible to establish four hierarchical groups, from which two stood out concerning productive characteristics. The group formed by hybrids Volumax, BRS 610, and XBS60329 presented lower averages for yield and lower percentage of panicle. Hybrids 866041 and 866042 show a higher total dry matter production, with values around 20,000 kg/ha.

Resumo em Inglês:

The objective of this study was to evaluate the effects of stalk/leaf ratio and the stage of maturity on the digestibility of the corn plant. Hybrids AG1051, AG4051, AG5011, DOW2B710, DOW2C577, DOW2A525, NB7315 and P30F90 were used, harvested at the one-half milk line (½ ML), three-quarters milk line (¾ ML) and black layer (BL) stages. A randomized block design was used in an 8 (hybrids) × 3 (stages of maturity) factorial design, with three replications. The means generated were used for grouping into high and low stalk/leaf ratio and a new analysis of variance was generated in a 2 × 3 (two groups and three stages of maturity) factorial design. The whole plant and its stalk, leaf, husk, cob and grain components were incubated in situ in the rumen of three cows for determination of degradability of dry matter and degradable neutral detergent fiber. Stalk/leaf ratio did not influence neutral detergent fiber content or the degradability of dry matter and neutral detergent fiber of any of the components, except for the cob, in which the high ratio group had greater degradable neutral detergent fiber contents. There was a reduction in the degradability of all the parts, except for the stalk and cob, and an increase in the neutral detergent fiber contents of the vegetative parts, except for the stalk. Unlike the vegetative components, the neutral detergent fiber contents of the whole plant decreased throughout the stages evaluated. For degradable neutral detergent fiber, there was a reduction in the whole plant and in its components. The advance of maturity reduces the quality of the vegetative components; however, this loss in the entire plant is moderated by grain filling. Forage quality depends more on the quality of the components than on their proportions in the dry matter.

Resumo em Português:

Verificou-se a influência da heterogeneidade de variâncias na avaliação genética de bovinos de corte da raça Nelore. Dados de pesos padronizados aos 365, 450 e 550 dias de idade foram estratificados com base no desvio-padrão fenotípico dos rebanhos para cada peso. Nas análises de múltiplas características, em que o mesmo peso foi considerado característica distinta em cada classe de desvio-padrão, as variâncias genéticas e residuais aumentaram com o desvio-padrão da classe. As estimativas de herdabilidade foram iguais a 0,34 e 0,36; 0,41 e 0,41, 38 e 49 nas classes de alto e baixo desvio-padrão fenotípico para os pesos aos 365, 450 e 550 dias, respectivamente. As correlações genéticas entre o mesmo peso nas classes de baixo e alto desvio-padrão foram iguais a 0,71; 0,80; e 0,84 para os pesos aos 365, 450 e 550 dias, respectivamente. As correlações de Spearman entre os valores genéticos, obtidos de análises múltiplas e de análise geral (sem as classes), e entre o mesmo peso nas classes de desvios-padrão, reduziram à medida que aumentou a intensidade de seleção sobre os reprodutores. A presença de heterogeneidade de variâncias causa maior impacto sobre a avaliação genética dos reprodutores sob intensidade de seleção elevada, sendo interessante sua consideração no processo de avaliação genética.

Resumo em Inglês:

Data from Nellore beef cattle breed were used to study the influence of variance heterogeneity on genetic evaluation. Adjusted weights at 365, 450 and 550 days of age were classified as high and low classes of standard deviation, based on phenotypic standard deviation of herds in each weight. At multiple trait analyses, where the same weight was considered a distinct characteristic regarding each class of standard deviation, genetic and residual variances increased as the standard deviation of the class increased. Genetic correlations between the same weight, in high and low phenotypic standard deviation classes were 0.71, 0.80 and 0.84 for weights at 365, 450 and 550 days, respectively. Spearman correlations between breeding values obtained from multiple trait analyses and general analysis (without classes), and between classes of standard deviations, lowered as the intensity of selection on sires increased. The presence of heterogeneity of variances has greater impact on the genetic evaluation of breeding under high intensity of selection, it is interesting your consideration in the process of genetic evaluation.

Resumo em Inglês:

Genetic and phenotypic parameters considering the genetic effect on hygienic behavior of queen and workers from 40 Africanized honeybees colonies were estimated separately. Maternal origin of queens was controlled whereas the paternal was unknown, and different groups of workers were considered in three seasons, October 2006, April 2007 and August 2007, but with the same queen. Colonies were 21 honey producers and 19 royal jelly producers. After the method of freezing capped brood, hygienic behavior was determined by the ratio between the number of dead capped brood removed at 24, 48 and 72 hours and the total number of capped brood at zero hour. Data was submitted to single and three traits analyses using Bayesian inference. Estimates of direct heritability at 24, 48 and 72 hours (0.10, 0.11 and 0.11) were identical to the motherly ones. Estimates by three trait analysis of direct heritability were 0.28, 0.15, 0.24, and of maternal heritability were 0.23, 0.29, 0.27, at 24, 48 and 72 hours, respectively. Correlations between maternal and genetic effects were 0.12, 0.09 and - 0.08 at, 24, 48 and 72 hours, respectively. Correlation between 24 and 48 hours was 0.49; between 24 and 72 hours, 0.40; and between 48 and 72 hours, 0.47. Moderate genetic correlations with the number of capped brood removed until 48 and 72 hours indicate that after the selection of a few generations, these traits can become an efficient criterion for selection in 24 hours.

Resumo em Português:

Objetivou-se determinar a idade à puberdade e maturidade sexual e sua relação com peso corporal e mensurações testiculares em tourinhos da raça Simental criados sob regime extensivo em clima tropical. Utilizaram-se 44 tourinhos com 1 a 30 meses de idade. As mensurações corporais e testiculares foram feitas mensalmente e os ejaculados coletados quinzenalmente, a partir dos seis meses de idade, utilizando-se o método de eletroejaculação. Observou-se idade à puberdade aos 13,42 ± 3,02 meses e maturidade sexual aos 21,43 ± 6,6 meses de idade, com peso corporal e perímetro escrotal, respectivamente, de 324,2 ± 23,7 kg e 26,90 ± 1,41 cm para a puberdade e 360 ± 69,04 kg e 34,88 ± 3,9 cm para maturidade sexual. Este estudo revelou idade tardia para a cronologia dos eventos reprodutivos, com relação direta do tipo de manejo adotado.

Resumo em Inglês:

The objective of this study was to determine the age at puberty and sexual maturity and its relationship with body weight and testicular measurements in Simmental young bulls raised under pasture conditions in a tropical climate. Forty-four young bulls at 1 to 30 months of age were used. Body and testicular measurements were made monthly and ejaculates collected fortnightly, from six months of age by using the method of electroejaculation. Age at puberty was 13.42 ± 3.02 months and sexual maturity was observed at 21.43 ± 6.6 months of age, with body weight and scrotal circumference of 324.2 ± 23.7 kg and 26.90 ± 1.41 cm for puberty and 360 ± 69.04 kg and 34.88 ± 3.9 cm to sexual maturity, respectively. This study found late age to the timing of reproductive events, with direct relation to the type of management adopted.

Resumo em Português:

Este estudo foi realizado para avaliar níveis de lisina digestível para suínos dos 30 aos 60 kg mantidos sob estresse por calor. Utilizaram-se 70 suínos machos castrados mantidos em ambiente a 30ºC e outros 70 em ambiente a 34ºC, distribuídos em delineamento de blocos ao acaso, com cinco tratamentos (0,83; 0,93; 1,03; 1,13 e 1,23% de lisina digestível), sete repetições e dois animais por unidade experimental. O ganho de peso diário dos animais mantidos a 30ºC aumentou até o nível de 1,04% de lisina digestível, mas a 34ºC não variou. O consumo de ração diário dos animais a 30 e a 34ºC não variou com os níveis de lisina. O consumo de lisina diário dos animais, em ambos os ambientes, aumentou de acordo com o nível de lisina da ração. A 30ºC, a conversão alimentar melhorou até o nível de 1,07% de lisina, enquanto a 34ºC não variou entre os níveis de lisina. Independentemente da temperatura, a eficiência de utilização de lisina reduziu conforme aumentaram os níveis de lisina e foi 4,4% pior no ambiente com temperatura mais elevada. A deposição de proteína na carcaça dos animais no ambiente a 30ºC aumentou até o nível de 1,05% de lisina, mas não variou no ambiente a 34ºC. A 30ºC, a deposição de gordura reduziu até o nível de 1,08% de lisina, enquanto a 34ºC, aumentou até o nível de 1,08% e foi, em média, 25,6% menor que a 30ºC. Os níveis de triiodotironina e tiroxina foram 35 e 30%, respectivamente, menores nos animais mantidos em ambiente a 34ºC, em que a frequência respiratória e temperatura retal também foram mais altas que as observadas nos animais mantidos a 30ºC. Os níveis de 1,04 e 0,83% de lisina digestível proporcionam maior ganho de peso e deposição de proteína em suínos mantidos, respectivamente, em ambientes a 30 e 34ºC.

Resumo em Inglês:

This study was conducted to evaluate levels of digestible lysine for pigs at 30 to 60 kg kept under heat stress. It was used 70 castrated animals kept in environment at 30ºC and others 70 kept at 34ºC, distributed in a randomized block design, with five treatments (0.83, 0.93, 1.03, 1.13 and 1.23% digestible lysine), and seven repetitions with two animals per experimental unit. The daily weight gain of the animals kept at 30ºC increased up to 1.04% of digestible lysine, whereas it did not change at 34ºC. Feed daily intake of animals at 30ºC and 34ºC did not change with levels of lysine. Daily lysine intake of animals, in both environments, increased according to the level of lysine in the diet. At 30ºC, feed conversion improved up to the level of 1.07% lysine, whereas at 34ºC, it did not vary among lysine levels. Regardless of the temperature, use efficiency of lysine decreased as levels of lysine increased and it was 4.4% worse in the environment with higher temperature. Protein deposition in carcass in the 30ºC environment increased up to the level of 1.05% lysine, but it did not change at 34ºC. At 30ºC, fat deposition decreased down to 1.08% lysine, whereas in the 34ºC environment, it increased up to 1.08%, and it was on average 25.6% lower than at 30ºC. Levels of triiodothyronine and thyroxine were 35 and 30%, respectively, which was lower in animals kept in the 34ºC environment, where respiratory rate and rectal temperature were higher than those observed in animals kept in the environment at 30ºC. The levels of 1.04 and 0.83% of digestible lysine provide greater weight gain and protein deposition in pigs kept in environments at 30ºC and 34ºC, respectively.

Resumo em Inglês:

This study was carried out to evaluate the creatine and maltodextrine dietetic supplementation of eventing horses. The experimental period consisted of 56 days, with 20 horses, which were randomly divided into four groups with different diets. Diets were: diet without supplement (Control); diet supplemented with creatine, 44.4 mg/kg body weight/day (20 g creatine/horse/day); diet supplemented with creatine, 88.8 mg/kg body weight/day (40 g creatine/horse/day); diet supplemented with maltodextrine, 222.2 mg/kg body weight/day (100 g/horse/day), during three days before each test. Every horse was submitted to three tests. Blood samples and heart rate were collected at rest, immediately after the tests and 10 and 20 minutes after the test. Supplementation with creatine (44.4 mg/kg body weight/day) and maltodextrine reduced plasma concentration of lactate in horses during tests. Supplementation of creatine and maltodextrine did not alter serum concentration of aspartate aminotransferase, γ-glutamyltransferase, urea or creatinine, but training affected blood biochemical variables in eventing horses.

Resumo em Inglês:

In order to evaluate the effects of dietary digestible lysine levels on performance and carcass traits of two genetic lines of pigs selected for meat deposition, from 60 to 100 days of age, a total of 120 crossbred barrows, with initial average body weight of 25.42 ± 2.08 kg were used. Pigs were allotted in a complete randomized block design, within a 4 × 2 factorial arrangement (four digestible lysine levels: 0.90, 1.00, 1.10, and 1.20%, and two genetic lines: A and B), with five replicates and three pigs per pen, which was the experimental unit. There was no interaction between genetic and digestible lysine levels for any variable of performance and carcass traits assessed. There was also no effect of digestible lysine levels in feed intake, body weight gain, and feed conversion. Digestible lysine intake of pigs increased linearly with increasing digestible lysine levels in the diets. Except for carcass yield that increased quadratically up to 1.04% estimate level of digestible lysine, there was no effect of lysine levels on the other carcass traits assessed (loin and ham yield, and amount of meat in the carcass). The digestible lysine level of 0.90%, corresponding to an estimated daily intake of 19.10 g, meets the requirements of castrated male pigs selected for meat deposition from both genetic lines, from 60 to 100 days of age.

Resumo em Português:

Neste experimento foram avaliados os efeitos de níveis de lisina digestível no desempenho, no balanço de nitrogênio e na digestibilidade de extrato etéreo em poedeiras Lohmann LSL entre 16 e 25 semanas de idade. Foram avaliados quatro níveis de lisina digestível (0,6; 0,7; 0,8 e 0,9% da ração) utilizando-se 160 poedeiras durante o período de 16 até 25 semanas de idade. As dietas foram isonutritivas, com 17% de PB e 2.800 (pré-postura) e 2.750 kcal (pré-pico) EM/kg. O delineamento inteiramente casualizado foi adotado com quatro níveis de lisina digestível avaliados em quatro repetições. Os níveis de lisina digestível não influenciaram o ganho de peso, os consumos de ração e de proteína e energia, a idade ao primeiro ovo, a produção e o peso dos ovos, os índices de conversão alimentar, a massa do ovo e os balanços de nitrogênio e extrato etéreo. Houve aumento linear positivo do consumo de lisina de acordo com os níveis dietéticos de lisina digestível. Os níveis de lisina utilizados não interferem no desempenho nem no balanço de nutrientes. Sugere-se o uso de 0,6% de lisina por quilograma de ração.

Resumo em Inglês:

In this experiment, the effects of digestible lysine levels on performance, nitrogen balance and fat digestibility in Lohmann LSL hens 16 to 25 weeks of age were evaluated. Four levels of digestible lysine (0.6, 0.7, 0.8 and 0.9% in ration) were assessed by utilizing 160 16-year-old laying hens 16 to 25 weeks of age. The diets were isonutritive with 17% CP and 2800 (pre laying) and 2750 (pre peak) kcal/kg. A completely randomized design was used with four lysine levels assessed in four replicates. The lysine levels did not influence weight gain, feed intake, protein and energy intake, age at first egg laying, egg production, egg weight, feed conversion indexes, egg mass, nitrogen balance or crude fat. There was positive linear increase on lysine intake according to the dietary levels of digestible lysine. Lysine levels do not influence the performance or the nutrients balance, and 0.6% of lysine per kilogram of feed is recommended.

Resumo em Português:

Conduziu-se este estudo com o objetivo de avaliar planos nutricionais de lisina digestível para suínos machos na fase dos 67 aos 165 dias de idade imunocastrados aos 107 e aos 135 dias. Foram utilizados 240 animais com peso inicial de 27,73 ± 1,57 kg distribuídos em delineamento de blocos ao acaso, com quatro planos nutricionais de lisina digestível para suínos imunocastrados (0,9-0,8-0,7; 1,0-0,9-0,8; 1,1-1,0-0,9 e 1,2-1,1-1,0%, respectivamente, dos 67 aos 107 dias, dos 108 aos 135 dias e dos 136 aos 165 dias), com quatro repetições e um plano controle para suínos castrados (1,1-1,0-0,9% de lisina digestível), com oito repetições de dez animais. O plano nutricional com a sequência de 1,1-1,0-0,9% de lisina digestível melhorou a conversão alimentar, reduziu a espessura de toucinho e aumentou a quantidade de carne magra na carcaça dos suínos em comparação aos demais planos nutricionais. As demais variáveis de desempenho e características de carcaça não foram influenciadas pelos planos nutricionais. Planos nutricionais com fornecimento de lisina digestível na sequência de 1,1-1,0-0,9%, respectivamente, para os períodos de 67 aos 107 dias, dos 108 aos 135 dias e dos 136 aos 165 dias, atendem às necessidades nutricionais de suínos machos imunocastrados aos 107 e aos 135 dias de idade.

Resumo em Inglês:

This study was conducted to evaluate nutritional plans of digestible lysine for boars 67 to 165 days of age, immunocastrated at their 107 and 135 days. Two hundred and forty animals, with initial body weight of 27.73 ± 1.57 kg, were sorted in a randomized block design with four nutritional plans of digestible lysine for immunocastrated pigs (0.9-0.8-0.7; 1.0-0.9-0.8; 1.1-1.0-0.9 and 1.2-1.1-1.0%, respectively from 67 to 107 days, from 108 to 135 days and 136 to 165 days) with four replications and a control plan for barrows (1.1-1.0-0.9% of digestible lysine) with eight replications and ten animals each. The nutritional plan with the sequence containing 1.1-1.0-0.9% digestible lysine improved feed conversion, reduced backfat thickness and increased the amount of lean meat of pigs carcass when compared to other nutritional plans. The other performance and carcass variables were not affected by nutritional plans. Nutritional plans with the sequence 1.1-1.0-0.9% of digestible lysine for periods of 67 to 107 days, 108 to 135 days and 136 to 165 days, respectively, meet the nutritional needs of immunocastrade boars 107 to 135 days old.

Resumo em Português:

O objetivo neste trabalho foi avaliar o peso vivo, o peso de pernas, os aspectos morfológicos das fibras musculares do músculo flexor longo do hálux e o perfil eletroforético das miosinas de cadeia pesada de quatro linhagens de frangos de corte criados nos sistemas de confinamento e semiconfinamento. Foram utilizados 1.440 pintos distribuídos em delineamento inteiramente casualisado em esquema fatorial 4 × 2, composto de quatro linhagens (Ross 305, Máster Gris, Label Rouge e Vermelhão Pesado) e dois sistemas de criação (confinamento e semiconfinamento), cada combinação avaliada com quatro repetições. Aos 28 e 84 dias de idade, foram abatidas quatro aves por tratamento, totalizando 64 aves. A eletroforese identificou a presença das três isoformas de miosinas, tipo MyHC-I, MyHC-IIa e MyHC-IIb, no músculo flexor longo do hálux dos frangos de corte. Com aumento da idade, a isoforma de miosina MyHC-II aumenta, enquanto a MyHC-I diminui. Somente aos 84 dias de idade, a expressão das isoformas de miosina do tipo MyHC-II foram influenciadas pela linhagem, confirmando o reflexo da seleção na linhagem Ross no músculo mais glicolítico.A linhagem Ross apresenta maior peso vivo, peso de perna, peso e área do músculo flexor longo do hálux em comparação às linhagens tipo caipira.

Resumo em Inglês:

The objective was to evaluate body weight, leg weight and morphologic aspects of the muscle fibers of the flexor hallucis longus muscle and electrophoretic profile of myosin heavy chain of four strains of broilers, reared in confinement and semi-confinement systems. 1440 chicks were randomly assigned in a 4 × 2 factorial arrangement: four strains (Ross 305, Master Gris, Label Rouge and Vermelhao Pesado), two production systems (confinement and semi-confinement), with four replicates for each treatment. Four birds were sacrificed for each treatment, at 28 and 84 d, totaling 64 animals. Electrophoresis technique identified the presence of three myosin heavy chain types: MyHC-I, MyHC-IIa and MyHC-IIb, in the flexor hallucis longus muscle of the broilers. There was increase in MyHC-II and decrease in MyHC-I, as age passed. Only at 84 days-old was the MyHC-II expression influenced by strain, confirming a response of selection in Ross lineage on a more glycolytic muscle. The Ross lineage has higher live weight, leg weight, weight and area of the flexor hallucis longus, compared to different chicken strains.

Resumo em Português:

Objetivou-se com este estudo avaliar níveis de energia líquida e ractopamina em dietas para leitoas em terminação sob conforto térmico. Foram utilizadas 40 leitoas com peso inicial de 67,4 ± 3,4 kg, distribuídas em delineamento de blocos ao acaso em esquema fatorial 2 × 4, composto de dois níveis de ractopamina, 0 e 20 ppm, em combinação aos níveis de energia líquida de 2.300; 2.424; 2.548 e 2.668 kcal/kg de ração, com cinco repetições, considerando cada animal uma unidade experimental. O período experimental teve duração de 28 dias. A temperatura do ar, a umidade relativa, a temperatura de globo negro e o índice de temperatura de globo e umidade foram de 21,5 ± 2,8ºC, 91,7 ± 6,8%, 21,7 ± 2,9ºC e 70,1 ± 3,7, respectivamente. Houve interação entre níveis de energia líquida e ractopamina, uma vez que a inclusão de 20 ppm de ractopamina em dietas contendo 2.668 kcal de energia líquida/kg de ração ocasionou redução da espessura de toucinho e aumento da porcentagem de carne magra e do índice de bonificação de carcaças. A inclusão de 20 ppm de ractopamina proporcionou aumento do ganho diário de peso e melhora na conversão alimentar, proporcionando maior peso de carcaça quente e aumentando a quantidade de carne magra nas carcaças. Dietas suplementadas com 20 ppm de ractopamina melhoram o desempenho e aumentam a produção de carne em leitoas em terminação. A ractopamina é ineficiente em reduzir a deposição de gordura e aumentar o percentual de carne magra na carcaça de leitoas alimentadas com dietas contendo baixa concentração de energia. O nível de 2.300 kcal de energia líquida/kg de ração atende à exigência nutricional de leitoas em terminação sob conforto térmico.

Resumo em Inglês:

This research was conducted to evaluate the net energy and ractopamine levels in the diet of finishing gilts kept under thermal comfort conditions. Forty gilts were used, with initial weight of 67.4 ± 3.4 kg, distributed in a randomized blocks design in a 2 × 4 factorial scheme composed of two levels of ractopamine, 0 and 20 ppm, combined with net energy levels of 2,300; 2,424; 2,548 and 2,668 kcal/kg of feed, with five replications, considering each animal per experimental unit. The experimental period lasted 28 days. Air temperature, relative humidity, black globe temperature, and black globe temperature and humidity index were 21.5 ± 2.8ºC, 91.7 ± 6.8%, 21.7 ± 2.9ºC and 70.1 ± 3.7, respectively. There was interaction between net energy levels and ractopamine, once the inclusion of 20 ppm of ractopamine in diets with 2,668 kcal of net energy/kg of feed resulted in a decrease in backfat thickness and consequently an increase in lean meat percentage and in carcass allowance index. The inclusion of 20 ppm of ractopamine caused an increased in daily weight gain, improved feed gain ratio, providing higher hot carcass weight and increasing the lean meat amount in carcasses. Diets supplemented with 20 ppm of ractopamine improve the performance and increase meat production of finishing gilts. Ractopamine is ineffective in reducing fat deposition and increasing the percentage of lean meat in the carcass of gilts fed with diets containing low concentration of energy. The level of 2,300 kcal of net energy/kg diet meets the nutritional requirement of finishing gilts under thermal comfort.

Resumo em Português:

Este trabalho foi realizado com o objetivo de avaliar o consumo voluntário, a digestibilidade aparente e o balanço de nitrogênio em ovinos alimentados com dietas contendo torta de dendê. A adição da torta de dendê foi avaliada nos níveis 0; 20; 40; 60 e 80% em substituição à silagem de capim-elefante utilizando-se 20 ovinos machos castrados em um delineamento experimental inteiramente casualizado. Em todas as formas como foram expressos, o consumo e a digestibilidade de nutrientes apresentou em geral resposta quadrática aos níveis de torta de dendê utilizados na dieta. A inclusão de torta de dendê nas dietas teve efeito quadrático também sobre o balanço de nitrogênio, que aumentou até o nível de 45% de adição desse subproduto e decresceu, devido ao baixo consumo de proteína bruta nos maiores níveis. A torta de dendê possui características próprias de um alimento volumoso e tem como principal limitação o baixo consumo alimentar, por isso, seu uso na alimentação de ovinos deve ser restrito ao nível máximo de 37,34% da dieta total.

Resumo em Inglês:

This research was conducted to evaluate the voluntary intake, the apparent digestibility and the nitrogen balance in sheep fed with diets containing palm kernel cake. The addition of palm kernel cake was assessed at the 0; 20; 40; 60 and 80% levels replacing the elephant grass silages by utilizing 20 castrated male sheep in a completely randomized design. In all the forms they were expressed, intake and digestibility of nutrients showed quadract effect at the levels of palm kernel pie utilized in the diet. The inclusion of palm kernel pie in the diets had quadract effect also on the nitrogen balance, due to low consumption of crude protein at higher levels. Palm kernel pie presents the characteristics of bulky feed, and its biggest limitation is the low feeding intake, hence, its use at sheep's feeding must be restricted to up to 37.34% of the total diet.

Resumo em Inglês:

This study aimed to validate the estimates of the ruminal degradation of total carbohydrates (TC), ruminal and total digestion of fibrous carbohydrates (FC) and microbial nitrogen flow in the abomasum evaluated by in vitro gas production technique (IVGP). Six ruminally and abomasally cannulated steers arranged in a double 3 × 3 latin square were used to measure described parameters with indigestible neutral detergent fiber (INDF) utilization as marker. Total and fibrous carbohydrates degraded in the rumen were estimated through digestion rates obtained for fibrous (FC) and non fibrous carbohydrates (NFC) using in vitro gas production technique, corrected for its respective ruminal and postruminal passage rates. The estimation of the total digestion of FC was done by the sum of ruminal and post-ruminal digestion of these compounds. The microbial nitrogen flow in the abomasum was estimated by the calculating the microbial efficiency of bacteria that ferment FC and NFC, utilizing the microbial growth rate obtained by the ruminal digestion rate for carbohydrate fractions in IVGP. The utilization of the in vitro gas production technique allows obtaining accurate estimates of the ruminal digestion of total carbohydrates, total and ruminal digestion of fiber carbohydrates and microbial protein flow in the abomasum.

Resumo em Inglês:

The objective of this paper is to assess the effects of the inclusion of different levels of green propolis extract in the diet of lambs in feedlot on ingestive behavior, nutrients digestibility, physiological parameters and performance. Eight lambs were distributed in double Latin Square with four treatments, corresponding to the inclusion levels (4, 8, 12, 16 mL) of green propolis ethanolic extract (30 g of ground crude propolis was infused in a 100-mL hydroalcoholic solution, 700 mL/L). The diets were composed of Brachiaria brizantha cv. MG5 hay and a commercial concentrate (roughage:concentrate ratio was 50:50) in a dry matter basis. No effect was observed on dry matter (31.2 g/kg of BW), crude protein, ether extract, neutral detergent fiber, non-fibrous carbohydrates and total digestible nutrients content (TDN) intakes. No significant effect was seen on the digestibility coefficients, presenting an average of 65.94% of TDN. The green propolis extract levels do not have a significant effect on behavior or physiologic parameters. Seeking to maximize feeding efficiency, the inclusion of 7.60 mL/day (2.1189 mg of dry matter and 0.1123 mg of flavonoids) of green propolis extract in the diet of lambs in feedlot is recommended.

Resumo em Inglês:

This study aimed at estimating the kinetic parameters of ruminal degradation of neutral detergent fiber from agroindustrial byproducts of cashew (pulp and cashew nut), passion fruit, melon, pineapple, West Indian cherry, grape, annatto and coconut through the gravimetric technique of nylon bag, and to evaluate the prediction equation of indigestible fraction of neutral detergent fiber suggested by the Cornell Net Carbohydrate and Protein System. Samples of feed crushed to 2 mm were placed in 7 × 14 cm nylon bags with porosity of 50 µm in a ratio of 20 g DM/cm² and incubated in duplicate in the rumen of a heifer at 0, 3, 6, 9, 12, 16, 24, 36, 48, 72, 96 and 144 hours. The incubation residues were analyzed for NDF content and evaluated by a non-linear logistic model. The evaluation process of predicting the indigestible fraction of NDF was carried out through adjustment of linear regression models between predicted and observed values. There was a wide variation in the degradation parameters of NDF among byproducts. The degradation rate of NDF ranged from 0.0267 h-1 to 0.0971 h-1 for grape and West Indian cherry, respectively. The potentially digestible fraction of NDF ranged from 4.17 to 90.67%, respectively, for melon and coconut byproducts. The CNCPS equation was sensitive to predict the indigestible fraction of neutral detergent fiber of the byproducts. However, due to the high value of the mean squared error of prediction, such estimates are very variable; hence the most suitable would be estimation by biological methods.

Resumo em Inglês:

Dry fecal matter production was estimated from neutral detergent indicators on indigestible fiber, indigestible acid detergent fiber, indigestible dry matter, incubated for 144 hours and 288 hours, as well as chromium oxide (Cr2O3) and enriched and purified isolated lignin (LIPE®) in two sampling schemes (3 and 5 days) on buffaloes. Sample consisted of five castrated animals with average weight of 300 ± 0.6 kg fed on elephant grass cv Cameroon (Pennisetum purpureum). Experimental design consisted of randomized blocks in subdivided plots. Production of dry fecal matter was overestimated when using Cr2O3, indigestible acid detergent fiber 144 hours, indigestible neutral detergent fiber 144 hours, indigestible neutral detergent fiber 288 hours and indigestible dry matter 144 hours, while indigestible acid detergent fiber 288 hours, indigestible dry matter 288 hours and LIPE® did not differ from total collection. The same result was observed for apparent digestibility of nutrients. There was no difference in dry fecal matter production and digestibility between both collection periods of 3 and 5 days, demonstrating that a collection period of three days can be used to estimate dry fecal matter production in buffaloes. A three-day period of sample collection, in order to estimate dry fecal matter production and apparent digestibility coefficients, is therefore recommended. The use of LIPE®, fibers in indigestible acid detergent and indigestible dry matter as indicators, both latter incubated for 288 hours, result in accurate estimates of dry fecal matter production in confined buffaloes, fed on a forage based diet.

Resumo em Inglês:

The study assessed performance, microbial protein synthesis, intake and digestibility of nutrients by beef heifers receiving levels of multiple supplements or nitrogen salt, in a self-controlled intake, on pasture, during the dry season. Thirty-five beef heifers, from 6 to 9 months of age and average initial body weight of 203.4 + 4.5 kg, were used. Study factors were: control - mineral mixture; nitrogen salt - 50% of urea + mineral mixture, at proportion of 1:1, and 50% of corn (75% of crude protein); levels of multiple supplementation - multiple supplements with different percentages of intake controller mixture (urea + mineral mixture, at the proportion of 1:1), corn and soybean meal (45% of crude protein). Supplement consumptions observed were: 115, 173, 572 and 1214 g/animal/day for animals fed on nitrogen salt, low, medium and high levels of multiple supplement, respectively. Supplemented animals had greater average daily gain, evidencing the positive linear effect of the levels of multiple supplementation on average daily gain. Overall, there were no significant differences between average daily gain of animals fed on multiple supplements or nitrogen salt. Supplementation increased the intake and digestibility of nutrients, except for digestibility of neutral detergent fiber, although the intake of digested neutral detergent fiber increased. Supplementation increased the production of microbial nitrogen as well as nitrogen losses in urine, although the quantity of nitrogen assimilated by bacteria, proportionally to intake, was higher. Supplementation improves nutritional parameters and weight gain.

Resumo em Inglês:

The objective of this study was to evaluate the thermal comfort of broilers reared under two lighting programs (almost continuous and intermittent) in broiler houses with yellow or blue lateral curtains. The experiment was carried out from June 24, 2004 until May 12, 2005. Six consecutive flocks were housed in four 12 × 10 m broilers houses internally divided into four pens of 200 birds each. Six flocks were raised on the same litter. The registration of data was accomplished at 3-hour intervals, for 24 hours twice a week. In the center of each pen and outside the house, dry and wet bulb temperatures, black globe temperature, and air velocity were collected. Based on the data collected at each time, air temperature (AT) (ºC), black globe humidity temperature index (BGHTI), radiant thermal load (RTL) (W/m²), and relative air humidity (RH) were determined. Harmonic analysis was used to estimate m, R, and f parameters. In general, the best results in terms of thermal comfort for the birds were found when near-continuous lighting program and yellow curtain were used.

Resumo em Inglês:

The objective of the present study was to evaluate mortality and performance, darkling beetle population (Alphitobius diaperinus), light intensity, electrical energy consumption and economic efficiency of broilers reared under two lighting programs (nearly continuous or intermittent) and two curtain colors (yellow or blue). The experiment was conducted between June, 2004 and May, 2005. Six flocks were sequentially housed in four 12 × 10 m broiler houses divided into 4 pens with 200 birds each. Litter was reused six times or until flock 6. Body weight and feed conversion were determined on days 21, 35, and 42 of each flock. Mortality was recorded daily. Electrical energy consumption was recorded at the end of the grow-out of each flock (every 42 days). A completely randomized design in a 6 × 2 × 2 factorial arrangement (flocks, lighting programs, curtains) with four replicates per treatment was applied. Broilers reared in houses with yellow curtains and under nearly continuous lighting programs presented the best feed conversion ratio and the highest body weight. Nearly continuous lighting programs resulted in 1.48 times more sudden deaths and 1.34 times higher general mortality when compared with intermittent lighting programs. Electrical energy consumption was 2.12 times higher in nearly continuous lighting programs in relation to intermittent lighting programs. The presence of darkling beetles was higher in broiler houses with blue curtains and intermittent lighting program. The economic analysis showed the feasibility of using a mixed system, with intermittent light program in winter and spring and nearly continuous lighting program in the summer and autumn, both in broiler houses with yellow curtains.

Resumo em Inglês:

The objective of the present study was to evaluate carcass and parts' yield, abdominal fat deposition and breast and foot pad blisters of broilers reared under two lighting programs (nearly continuous or intermittent) in broilers houses with yellow and blue curtains. The experiment was conducted between June, 2004 and May, 2005. Six flocks were sequentially housed in four 12 × 10 m broiler houses divided into 4 pens with 200 birds each. The litter was reused six times or until flock 6. A completely randomized design in a 6 × 2 × 2 factorial arrangement (flocks, lighting programs, curtains) with four replicates per treatment was applied. A total of 288 birds were evaluated for carcass yield. Curtain color did not affect carcass or parts' yield. The effect of lighting program and curtain color on carcass yield may depend on other factors related to flock. Intermittent lighting program promoted the highest drumstick and thigh yields. Lighting programs and curtain colors did not affect abdominal fat deposition or the presence of breast and foot pad blisters.

Resumo em Inglês:

The objective of this study was to evaluate the vegetal and animal production of a natural pasture on a Mollisol soil in the region of Campanha, in RS. The experimental design consisted of complete randomized blocks with three replicates, which enables the comparison between natural unfertilized pastures with fertilized pastures and pastures fertilized and overseeded with Lolium multiflorum, Lotus corniculatus cv. São Gabriel and Trifolium repens cv. Lucero (NPO). Data were submitted to the analyses of variance considering seasons of the year as time repeated measurements. Aberddeen Angus calves of about nine months of age were used in continuous stocking with variable stocking rate in order to maintain forage offer at 13% of live weight. Data were collected between July 7th (2007) and May 3rd (2008), totaling 302 days. Fertilized and oversown pastures showed higher green forage mass mainly in the spring, as result of higher dry matter (DM) accumulation rate. Average daily live-weight gain for fertilized pasture (0.581 kg/day) was higher than for natural pasture (0.473 kg/day). Higher live-weight gains were obtained in the fall (0.869 kg/day). Stocking rate showed interaction with the seasons of the year, with higher stocking rates obtained in oversown pasture (701 kg of LW/ha) and fertilized pasture (667 kg of LW/ha) during the spring. Live-weight gain per hectare from natural pasture (224 kg LW/ha) was lower than on fertilized (310 kg LW/ha) and over-sown pasture (287 kg LW/ha). Forage mass, dry matter content, forage allowance and pasture height explained 61% of the average live weight gain. Despite the good performance of native grasslands in this region in its natural condition, the utilization of different inputs as fertilization and oversowing of winter cultivated species promoted positive differences in forage production and its distribution along the year and in animal yield.

Resumo em Português:

Avaliou-se a viabilidade de abater animais de distintos grupos raciais com até quatro dentes em diferentes tipos de pastagem: natural, adubada, e melhorada por fertilização e sobressemeadura de espécies hiberno-primaveris. O delineamento experimental utilizado foi o de blocos ao acaso, com três repetições. Os dados foram agrupados em estações do ano (inverno e primavera) e submetidos à análise de variância. Foram utilizados novilhos de corte Angus e mestiços, ambos com média de idade inicial de 20 meses. A massa de forragem total e a altura do pasto apresentaram diferenças entre os tipos de pastagem e as estações do ano. A taxa de lotação e a massa de forragem verde sofreram interação entre o tipo de pastagem e a estação do ano. O ganho por área ao longo do experimento foi maior na pastagem adubada (259 kg/ha) e melhorada (263 kg/ha) em comparação à pastagem natural (126 kg/ha). O ganho médio diário foi maior para os novilhos Angus (1,087 kg/dia) e na estação de inverno (1,251 kg/dia). Não houve diferença para a área de olho-de-lombo entre o tipo de pastagem e grupo racial na data do abate. A espessura de gordura subcutânea sofreu interação entre o tipo de manejo e o grupo racial, uma vez que novilhos mestiços depositaram mais gordura na pastagem adubada e novilhos Angus na melhorada. Animais mestiços atingiram menor peso ao abate (505 kg), porém maior rendimento de carcaça (51,6%). Somente os animais mantidos na pastagem natural não atingiram acabamento suficiente para a comercialização. A utilização de fertlizantes e sementes na pastagem natural possibilita o abate de novilhos precoces independente do grupo racial. O ambiente pastoril determina diferentes respostas produtivas conforme a genética utilizada. O cruzamento é uma alternativa para incrementar atributos importantes da carcaça e diminuir o tempo de terminação.

Resumo em Inglês:

The viability for slaughtering steers of distinct breeds with four teeth at most, on different types of pasture (natural, fertilized and fertilized with overseeding) with winter species was evaluated. The experimental design was randomized blocks with three replicates (padlocks). Data were analyzed according to the seasons (winter and spring) and submitted to analyses of variance. Angus calves and crossbred calves were used, both 20 months of age on average. Total forage mass and the pasture height showed differences between pasture type and seasons. Carrying capacity rate and green forage mass showed interaction between pasture type and season. Yield per unit area during the experimental period was higher in fertilized (259 kg/ha) and oversown pasture (263 kg/ha) than natural pasture (126 kg/ha). Average live-weight gain was higher for the Angus steers (1.087 kg/day) and during the winter (1.251 kg/day). Rib eye area did not show statistical difference between the pasture type and breeds at slaughtering time. Fat thickness showed interaction according to pasture and breeds, where crossbred steers were fatter on fertilized pasture and Angus steers were fatter on oversow pasture. Crossbred animals got lower slaughtering weight (505 kg), yet higher carcass yields (51.6%). Only steers kept on natural pasture did not reach enough fatness for commercialization. The use of fertilizer and seed on the natural pasture allows for slaughtering young steers regardless of the breed. Pasture condition allows different productive performances according to the animal genetics used. Crossbreeding is an alternative to increase important attributes on carcass and to reduce the finishing phase duration.

Resumo em Português:

O objetivo neste estudo foi avaliar o custo de produção e a resposta econômica da utilização de casca de soja (CS) associada a duas fontes de nitrogênio não-proteico (NNP) na terminação de cordeiros em confinamento. Foram utilizados 80 cordeiros mestiços Suffolk, com idade inicial de 69 ± 6 dias e peso vivo inicial de 23,11 ± 1,78 kg. Os animais foram distribuídos em quatro grupos, cada um com uma dieta formulada com uma fonte de NNP: grupo ureia convencional, na proporção de 1%; grupo ureia protegida, na proporção de 1%; grupo ureia protegida convencional, na proporção de 1% + 0,5% de ureia convencional, da dieta total, respectivamente; e grupo controle, sem fonte adicional de NNP. O custo total de produção do cordeiro até a desmama foi de R$ 85,27/animal. Entre os componentes desse custo, a categoria de ovelhas foi a principal contribuinte, com 68,55%, seguida pelos custos referentes ao próprio cordeiro (0-67 dias), que representaram 25,57%, e a dos carneiros, com participação de apenas 5,88%. O custo total médio da terminação em confinamento foi de R$ 57,73/cordeiro. O custo operacional efetivo (COEf) representou R$ 57,35, ou 99,33% do custo total à terminação. As variáveis de maior representatividade do COEf foram alimentação (61,56%) e impostos (31,06%). As dietas que permitiram obter margem bruta/cordeiro positiva foram aquelas com ureia convencional e sem fonte adicional de NNP (R$ 1,77 e R$ 4,35), respectivamente. No entanto, todas as dietas apresentaram margem líquida e resultado econômico negativos. Em sistemas de terminação de cordeiros em confinamento, o uso de dietas sem fonte adicional de nitrogênio não-proteico é a opção que permite obter melhor resultado zootécnico e econômico.

Resumo em Inglês:

The aim of this study was to evaluate the production costs and economic return of soybean husks (CS) associated with two non-protein nitrogen (NNP) sources, in feedlot finishing lamb. Eighty (80) Suffolk cross lambs, averaging initial age of 79 ± 6 days and initial live weight of 23.11 ± 1.78 kg were used. The animals were grouped in four experimental lots accordingly to NNP source: conventional urea group (CUG, n = 20), which received 1% of common urea; protected urea group (PUG, n = 20), which received 1% of protected urea, at the ratio of 1% + 0.5% conventional urea, of total diet, respectively; and control group, with no additional source of NNP. Total production cost (CT) of lambs at weaning was R$ 85.27/animal. In this cost ewes contributed with 68.55%, followed by the lamb cost (0-67 days), which represented 25.57% and rams with only 5.88%. The average CT in feedlot finishing was of R$ 57.73/lamb. Effective operational cost (COEf) represented R$ 57.35 or 99.33% of CT finishing. Variables of higher representativeness of COEf were: ration (61.56%) and taxes (31.06%). Diets with higher positive gross margin (MB)/lamb were GUC and CG (R$ 1.77 and R$ 44.35), respectively. All diets presented negative net margin (ML) and economic return (RE). In finishing systems of feedlot lamb, the use of diets with no additional source of non-protein nitrogen is the option that allows better economic and productivity results.