José Antônio de Freitas

Avaliação do consumo e ganho de peso de novilhos em pastejo rotacionado de capim-elefante (Pennisetum purpureum, Schum.) cv. Napier, na estação chuvosa

The research was conducted in the experimental farm of the EPAMIG-Leopoldina, MG, to evaluate intake of elephantgrass, the effectiveness of limiting grazing time to four daily hours for keeping intake close to maintenance level, and the weight gain of thirty-six steers during five successive periods of thirty-six days, during the rainy season. The treatments were: free access to pasture (unlimited grazing) and restricted grazing. The availability of green dry matter varied from 4.0 to 7.8 kg/100kg LW. The average daily weight gain of animals with free access to pasture was 516.5 g and their dry matter intake corresponded to 1.61 times that from the restricted grazing ones. The estimated gain per hectare was 423.5 kg, which is within the range reported for elephantgrass in Brasil. Metabolizable energy intake, per unit metabolic size, remained stable in the first three periods and increased in the last two, during which the highest weight gains of the animals. Four daily hours grazing period ensured intake close to maintenance level.

Composição corporal e exigências de energia de mantença em bovinos Nelore, puros mestiços, em confinamento

The objectives of this trial were to estimate the body composition of fat and protein and the net energy requirements for maintenance of purebred and crossbred Nellore. Seventy-two young bulls averaging 10 to 11 months of age from four genetic groups were used: 18 Nellore, 18 F1 Nellore x Angus, 18 F1 Nellore x Brown Swiss and 18 F1 Nellore x Simental with initial average weights of 286, 309, 333 and 310 kg, respectively. A completely randomized design was adopted and bulls from the four genetic groups were fed diets containing: 30, 40, 60 and 70% of concentrate. Three animals from each genetic group were feed restricted while other three bulls were slaughtered at the beginning of the trial and used as reference. The net energy requirements of maintenance were obtained by regressing heat production (kcal/kg0.75/day) on metabolizable energy intake (Mcal/kg0.75/day) extrapolating to zero level of metabolizable energy intake. There was no difference in net energy requirements for maintenance among genetic groups. Body contents of fat, protein and fat concentration (g/kg EBW) increased, respectively, 260.2, 92.6 and 67.8% when body weight increased from 250 to 550 kg whereas body protein concentration reduced 10.9%. The identity test of the non-linear model indicated no significant differences among genetic groups for body composition of fat, protein and energy as well as for net energy requirements for maintenance. The estimated net energy requirement for maintenance was 79.45 kcal/kg0.75/day in this study.

Net efficiency of metabolizable energy utilization of purebred and crossbred Nellore young bulls fed diets with different concentrate levels

The objective of this trial was to estimate the efficiency of utilization of metabolizable energy (MEEU) for maintenance (Km) and weight gain (kg) of feedlot purebred and crossbred Nellore. Seventy-two young bulls averaging 10 to 11 months of age from four genetic groups: Nellore, F1 Nellore x Angus, F1 Nellore x Brown Swiss and F1 Nellore x Simental and initial average body weights of 286, 309, 333 and 310 kg, respectively, were used in this study. A completely randomized design with a 4x4 factorial arrangement was adopted and bulls from the four genetic groups were fed diets containing: 30, 40, 60 and 70% of concentrate on dry matter basis. Three animals from each genetic group were assigned to the maintenance group and other three were slaughtered at the beginning of the trial. The intake of metabolizable energy for maintenance (MMEI), expressed in Kcal/kg0.75, corresponded to the point in which the coefficient between fasting heat production (FHP) and MMEI was closer to 1. The MEEU for maintenance (Km) was estimated by dividing FHP by MEIm while that for gain (Kg) was estimated by regressing retained energy (kcal/kg0.75) on MEIg. The ME requirements were obtained by dividing the net energy requirements by Km. Genetic group and dietary level of concentrate did not significantly affect Km and Kg that averaged 0.67 and 0.40, respectively. The ME requirements for gain (MEg) and the total ME requirements (MEt) followed the increase in body weight. However, the requirement of MEt and MEg per unit of empty body weight (EBW) decreased as body weight increased indicating a greater efficiency of metabolizable energy utilization.The objective of this trial was to estimate the efficiency of utilization of metabolizable energy (MEEU) for maintenance (Km) and weight gain (kg) of feedlot purebred and crossbred Nellore. Seventy-two young bulls averaging 10 to 11 months of age from four genetic groups: Nellore, F1 Nellore x Angus, F1 Nellore x Brown Swiss and F1 Nellore x Simental and initial average body weights of 286, 309, 333 and 310 kg, respectively, were used in this study. A completely randomized design with a 4x4 factorial arrangement was adopted and bulls from the four genetic groups were fed diets containing: 30, 40, 60 and 70% of concentrate on dry matter basis. Three animals from each genetic group were assigned to the maintenance group and other three were slaughtered at the beginning of the trial. The intake of metabolizable energy for maintenance (MMEI), expressed in Kcal/kg0.75, corresponded to the point in which the coefficient between fasting heat production (FHP) and MMEI was closer to 1. The MEEU for maintenance (Km) was estimated by dividing FHP by MEIm while that for gain (Kg) was estimated by regressing retained energy (kcal/kg0.75) on MEIg. The ME requirements were obtained by dividing the net energy requirements by Km. Genetic group and dietary level of concentrate did not significantly affect Km and Kg that averaged 0.67 and 0.40, respectively. The ME requirements for gain (MEg) and the total ME requirements (MEt) followed the increase in body weight. However, the requirement of MEt and MEg per unit of empty body weight (EBW) decreased as body weight increased indicating a greater efficiency of metabolizable energy utilization.

Exigências nutricionais em macronutrientes minerais (Ca, P, Mg, Na e K) para novilhos de diferentes grupos genéticos

The objective of this trial was to determine the macrominerals requirements (Ca, P, Mg, Na, and K) for young bulls from different genetic groups. Forty-four young bulls from the following genetic groups were used: Nellore, F1 Nellore x Aberdeen-Angus, F1 Nellore x Brown Swiss, and F1 Nellore x Simmental. Animals averaged 362 ± 35 kg of initial body weight and between 10 to 11 months of age. Diet contained signal grass hay (Brachiaria decumbens, Stapf.), soybean meal, ground corn, molasses, and macro and microminerals premix. The net requirements for weight gain of each macromineral were obtained by the first derivative of their respective equations generated from non-linear regression of the mineral content (Ca, P, Mg, Na, and K) in function of the animal empty body weight. The equation obtained from regressing empty body weight on weights taken immediately before slaughter was used for the conversion of body weight into empty body weight. The macrominerals requirements for maintenance were estimated using the NRC and ARC models recommendation while absorption coefficients used were those proposed by the ARC model. The model test of identity indicates no difference comparing regression equations for all studied macrominerals among the four genetic groups.

Parâmetros e tendências genéticas para pesos de várias idades em bovinos Nelore

The study aimed to was estimate the genetics parameters, correlations and trends for the weight of Nellore breed bovines at 205, 365 and 550 days of age. Genetics analysis was carried out by the methodology of mixing models, the statistical model containing the aleatory direct and maternal genetic effects, the uncorrelated maternal permanent environmental effect and the error, as fixed effects of contemporary group (farm, sex, season, water and drought, the year of birth of the calf), and the covariable age of dam. The genetic trends were estimated by linear regression of the breeding values on years of birth of the animals. Estimates of direct heritabilities were 0.13 ± 0.03 to W205; 0.03 ± 0.02 to W365; and 0.12 ± 0.04 to W550. Genetic correlations were of 0.55 a 0.85. The genetic parameters allow gains through selection and, according to the correlations, selection for weight gain to a certain age will allow gains weight at later ages, despite the gains are slow due to low heritability coefficients.

Interação genótipo x ambiente sobre características produtivas e reprodutivas de fêmeas Nelore

Genetic parameters were estimated and the genotype x environment interaction was evaluated for weight adjusted for 420 days old, age at first calving and first calving interval, in females of the Nelore raised in three regions in the state of Mato Grosso do Sul. The statistical model contained the genetic effects and direct additive (random effects) and residual, as fixed, the effects of farm and contemporary group. Analyses were performed with univariate and bivariate animal model. Heritability estimates were 0.41; 0.16; 0.09; for W420, AFC and FCI, respectively. When was utilized the Spearman correlation to compare the variation in the ordering of the expected progeny differences, there was noted the change in classification of the sires from region to region. These results show evidence of genotype by environment interaction for the traits studied, with possibility of breeders selected as top genetic merit for a region not be for others.

High detection rate and genetic diversity of picobirnavirus in a sheep flock in Brazil

This study reports the detection by RT-PCR and molecular characterization of partial RdRp gene of picobirnavirus (PBV) dsRNA in fecal samples (n = 100) from a meat sheep flock in southern Brazil. The analysis of the results allowed the identification of two important characteristics of PBV infection. The first was the high frequency of infection in the sheep flock evaluated where 62% of the analyzed fecal samples were PBV-positive. The second was the high genetic variability found in field strains of ovine PBV genogroup I circulating in animals of the same sheep flock.

Carcass and meat traits, and non-carcass components of lambs fed ration containing increasing levels of urea

The objective of this study was to evaluate the carcass and meat traits, and the non-carcass components of crossbred Dorper lambs fed diets with increasing levels of urea (0.0, 0.5, 1.0, and 1.5% of dry matter – DM). The experimental design was completely randomized with four treatments (urea inclusion levels) and six replicates per treatment. Lambs were fed ad libitum for 56 days and slaughtered at 37.9 ± 5.1 kg of body weight (BW). The weight and yield of carcass before and after cooling were not influenced by urea levels, with average values of 16.9 kg and 44.6% for cold carcass weight and yield. Urea levels did not affect the morphometric measurements, the fat deposition on the carcass, the weight of carcass cuts and the weight of non-carcass components. There was a quadratic effect of urea levels on the loin yield, which may achieve maximum value of 11.31% with the inclusion of 0.84% DM urea in the feed. The pH and the color coordinates L* (brightness), a* (red intensity) and C* (saturation) of the meat also showed quadratic response to the urea levels, where in the minimum value of 5.53 for pH, maximum value of 48.67 for L* and minimum values of 14.04 and 16.21 for a* and C* may be obtained by including 0.53 to 0.70% DM urea in the ration. The inclusion of 0.84% DM urea in the ration is recommended to obtain maximum yield of loin and meat with attractive characteristics to the consumer, which is characterized by high red intensity and brightness. If consumers have preference for lamb meat with a more intense red color, the inclusion of 1.5% DM urea should be considered in the ration formulation.

Inoculation of Bradyrhizobium japonicum (Kirchner, 1896) Jordan (1982) (Bradyrhizobiaceae) on Inga edulis Mart. (Leguminosae, Mimosoideae)

1Centro Universitário Norte do Espírito Santo – CEUNES/UFES. Rodovia BR 101 Norte, km. 60, Bairro Litorâneo, São Mateus – ES, Brazil, 29932-540. 2Escola Nacional de Botânica Tropical, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro. Rua Pacheco Leão, 915, sala 107, Jardim Botânico, Rio de Janeiro – RJ, Brazil, 22460-038. 3Centro de Ciências e Saúde (CCS), Universidade Federal do Rio de Janeiro. Av. Carlos Chagas Filho 373, Bloco J sala 25, Ilha do Fundão, Rio de Janeiro, RJ, Brazil, 22541-900. 4Faculdade Católica Salesiana do Espírito Santo. Av. Vitória, a950, Forte São João, Vitória – ES, Brazil, 29017-950.

Estabilidade e adaptabilidade de touros Tabapuã para característica de desempenho em função do índice de rebanhos

In order to study the stability and adaptability of Tabapua cattle for the characteristic weight at 120 days of maternal effect, we used methods based on linear regression. The analysis included differences in the expected progeny of five sire sin herds located in four farms in the states of Bahia, (herds 1and 2), Parana (herd 3) and Minas Gerais (herd 4). The results show that the performance of bulls depend largely on the genetic variability of the matrices for different characteristics in herds studied, allowing the recommendation of a specific breeding herd. Analyses of adaptability and stability discriminated performance differences in herds. Bulls were identified as adapted and perfectly stable, bulls with general adaptation, and with specific adaptation to favorable and unfavorable environments.