Scielo RSS <![CDATA[Revista Brasileira de Zootecnia]]> vol. 41 num. 8 lang. en <![CDATA[SciELO Logo]]> <![CDATA[<b>Apparent nutrient digestibility and mineral availability of protein-rich ingredients in extruded diets for Nile tilapia</b>]]> Apparent digestibility coefficients (ADC) of gross energy and dry matter (DM) and mineral availability were evaluated for eight protein-rich ingredients (corn gluten meal, soybean meal, cottonseed meal at 280.0 and 380.0 g/kg, poultry by-product meal, meat meal, fish meal and feather meal) in compound diets for Nile tilapia. Chromic oxide was used as inert digestibility marker. Higher ADC values of DM and energy were, respectively, 0.862 and 0.881 for corn gluten meal, 0.811 and 0.888 for poultry by-product meal; 0.729 and 0.731 for feather meal; 0.666 and 0.754 for fish meal; 0.578 and 0.642 for soybean meal; 0.476 and 0.652 for meat meal at 450.0 g/kg; 0.352 and 0.449 for cottonseed meal at 380 g/kg; and 0.251 and 0.324 for cottonseed meal at 280.0 g/kg. The highest average mineral availability was for poultry by-product meal (0.582), and the lowest calcium and phosphorus availability were recorded for cottonseed meal at 280.0 g/kg. Therefore, poultry by-product meal appears to be the best ingredient for using in Nile tilapia diets. <![CDATA[<b>Morphogenetic traits and biomass accumulation of <i>Brachiaria brizantha</i> cv. Xaraés subjected to nitrogen doses</b>]]> The objective of this experiment was to evaluate the morphogenetic traits and biomass accumulation of Brachiaria brizantha cv. Xaraés subjected to doses of N (0, 125, 250, 375 and 500 kg.ha-1 N). The treatments were arranged in a completely randomized design with four replications. Morphogenetic traits and biomass accumulation of dry matter (DM).ha-1 were evaluated. The results were subjected to statistical analysis by grouping the data in two periods, rainy season and throughout the year. Nitrogen doses influenced leaf appearance in the rainy season and throughout the year, with significant increase in leaf elongation during the rainy season, an increase of 56% compared with control. During this period, maximum dose of N (248.1 kg.ha-1) produced 214.49 DM of leaf blade, which was 133% higher than the control. However, the higher N dose in the rainy season resulted in an increase of 137% in the stalk accumulation compared with non-fertilized grass; estimating maximum accumulation of salk of 84.97 of DM for the application of 326.2 kg.ha-1 N. Doses of N also intensified leaf senescence during the rainy season and throughout the year. The control treatment presented 32% less senescence compared with maximum N dose (270.1 kg.ha-1 N) in the rainy season. Forage loss was estimated at 26.08 kg DM at the maximum dose of 295.0 kg.ha-1 N for this period. All variables studied responded positively to N supply in the rainy season. The accumulation of biomass of the plant reached the maximum point with fertilization close to 250 kg.ha-1 N in the rainy season and 375 kg.ha-1 N throughout the year. <![CDATA[<b>Prevention of natural grassland invasion by <i>Eragrostis plana</i> Nees using ecological management practices</b>]]> The objective of this research was to evaluate the effects of different types of disturbance on the ability of the natural grassland to avoid the invasion of Eragrostis plana Nees (South African lovegrass). The experiment was carried out in Dom Pedrito, Rio Grande do Sul, Brazil, in an area free of South African lovegrass, from Feb. 2004 to Apr. 2007. The treatments were: 1) grassland management regimes: exclusion; low grazing intensity (rotational grazing), ±10 cm; and high grazing intensity (continuous grazing), ±5 cm; 2) initial levels of soil disturbance: high grassland, ±10 cm; low grassland, ±5 cm height; and low grassland with scarified soil; 3) fertilization regimes: without fertilization; phosphorus; and nitrogen. The experimental design was a split-split-plot type in complete blocks, with three replicates. Three winter cultivated species - Trefoil repens L., Lotus corniculatus L., Lolium multiflorum Lam. and South African lovegrass -were sown in 54 split-splitplots (split-plots: low grassland, and low grassland with scarified soil). The other 27 split-split-plots (split-plots: high grassland) were sown only with South African lovegrass. The grassland height, plant number of South African lovegrass, grassland dry mass and photosynthetic active radiation intercepted (FARint) at the soil level were recorded. The fertilization regimes did not influence the South African lovegrass plant number. The initial levels of soil disturbance and grassland management regimes influenced the invasion of South African lovegrass. The invasion was favored by the lower grassland height and lower forage mass, higher intensity of the soil disturbance, and higher FARint due to the continuous grazing. On the contrary, higher grassland height, higher forage mass, lower soil disturbance and lower FARint, associated with rotational grazing or exclusion, showed higher potential to control the invasion of South African lovegrass in the natural grassland. <![CDATA[<b>Tillering and biomass partitioning of Mombasa grass under nitrogen fertilization during regrowth</b>]]> Biomass partitioning in forages is highly variable during plant development and with the rate of nutrient supply. This study was carried out with the objective to evaluate the tillering pattern and biomass partitioning of Mombasa grass (Megathyrsus maximus cv. Mombaça) subjected to rates of nitrogen (N) during regrowth. The treatments consisted of three weekly rates of N: control (without N supply), 25 and 50 mg dm-3 of N, which were evaluated by 1, 2, 4, 8, 16 and 32 days after defoliation. The design was of completely randomized blocks in a 3 × 6 factorial arrangement with three replicates. The number of tillers was measured and harvesting and weighting of the following morphological components were performed: leaf (leaf blades), pseudostem, stem base and root. Interaction between N rates and regrowth times was found for all variables analyzed. The N supply increased the number and weight of tiller (up to 117.3 and 167.6%, respectively), as well as the shoot dry matter yield of Mombasa grass. That effect was most significant particularly at 32 days of regrowth. Among the treatments receiving N supply, the highest N rate was more significant to leaf and shoot yield only after 6-11 days of regrowth. High N supply must be applied to Mombasa grass only after that time and the biomass harvested between 24-28 days of regrowth. <![CDATA[<b>Nitrogen fertilization strategies for xaraes and tifton 85 grasses irrigated in the dry season</b>]]> An experiment was carried out to assess rates and nitrogen fertilization strategies on the forage yield using irrigation to supply the water deficit during the dry season. The grasses Cynodon spp cv. tifton 85 and Brachiaria brizantha cv. Xaraés were cultivated with nitrogen (N) at levels of 200 and 400 kg/ha according to strategies: 1) half dose applied during the rainy season (RS) and half during the dry season (DS); 2) 1/3 during the RS and 2/3 during the DS; 3) 2/3 during the RS and 1/3 during the DS; 4) all doses applied during the DS. In each season the dose was divided in three applications. Eleven harvests were conducted: six in the RS and five in the DS. When 2/3 of N was applied in the DS, forage yield in this period was statistically equivalent to those obtained in the RS in three of the five harvests for both 200 and 400 kg/ha of N. With 100% of N applied in the DS, the yield of four of five cuts of forage was similar to that obtained in the RS for both rates of N. The strategy of applying more N in the DS rather than in the RS was effective, keeping the yield steadily throughout the year. The application of 100% of the dose of 200 kg/ha N and 2/3 of the dose of 400 kg/ha N both in the dry period, under irrigation, promote uniform productions per harvest throughout the year. <![CDATA[<b>Dynamics of production and forage utilization on elephant grass pastures managed with different post-grazing heights</b>]]> This study was conducted to evaluate the daily production of forage and its morphological components, as well as the potential of forage utilization in pastures of Pennisetum purpureum cv. Napier managed with three post-grazing heights (30, 50 and 70 cm). Two experiments were carried out: one from February to May 2009 and another from December 2009 to May 2010, characterizing months of summer and fall. The experimental design was of completely randomized blocks with three replicates. The grazing was performed by crossbred heifers of approximately 270 kg body weight, when the sward intercepted 95% of the incoming light. In both experiments, the pastures managed with post-grazing height of 30 cm, in the summer months (December to March), presented lower daily production of leaves and stems, as well as less daily leaf senescence, which resulted in lower daily forage production and accumulation in comparison with those managed at 70 and 50 cm. In the period from February to March 2009 (experiment 1) and December 2009 to March 2010 (experiment 2), pastures presented greater daily production of leaves and forage, greater daily forage accumulation and more daily leaf senescence in relation to the months of April and May 2009 and 2010. On the other hand, the daily production of stems was higher in the fall, in comparison with the summer. Therefore, elevation in the post-grazing height, especially in the summer, increases the regrowth vigor of elephant grass cv. Napier. <![CDATA[<b>Frequencies and intensities of defoliation in Aruana guineagrass swards</b>: <b>morphogenetic and structural characteristics</b>]]> The objective of this study was to evaluate the morphogenetic and structural characteristics of Aruana guineagrass pastures (Panicum maximum cv. Aruana) subjected to rotational stocking by sheep. The treatments corresponded to grazing when swards reached 95 or 98% of interception of incident light (LI) until post-grazing heights of 10 and 15cm and were allocated to experimental units (plots of 196 m²), according to a 2 × 2 factorial arrangement in a completely randomized design, with three replications, from January to May 2009. The morphogenetic assessments included: leaf appearance and elongation rates (LAR and LER), phyllochron (PHY) and leaf life span (LLS). Structural evaluations assessed the number of green leaves (NGL), dead leaves (NDL) and expanded leaves (NEL) per tiller, tiller population density (TPD) and final leaf length (FLL). The pre-grazing sward height relatively constant during the experimental period, with values ranging between 30 and 40 cm for treatments of 95 and 98% of LI, respectively, indicating potential for the development and use of management practices based on pasture conditions goals. The morphogenetic and structural characteristics were influenced by the frequency and intensity of grazing adopted, as well as by the seasons, implying that the capacity and speed for the recovery of Aruana grass pastures after grazing depend mainly on the management and edaphoclimatic conditions. The best grazing management for Aruana guineagrass is 95% canopy light interception, i.e., 30 cm pre-grazing height pastures interrupted when reaching 15 cm residue. <![CDATA[<b>Tabapuã breed in Northeastern Brazil</b>: <b>genetic progress and population structure</b>]]> The objective of this study was to evaluate the history of the Tabapuã breed in Northeastern Brazil by determining its population structure and genetic progress. Pedigree information from animals born in the period between 1965 and 2006 and weight-adjusted data at 205 (W205), 365 (W365) and 550 (W550) days of age for bovines born between 1975 and 2006 were used. The (co)variance components and genetic value were estimated using the application MTDFREML. Also, the software ENDOG was used for pedigree analysis and parameter estimation based on the probabilities of gene origin, inbreeding and average generation interval. The heritability coefficients for direct genetic effects were 0.21±0.03, 0.26±0.04 and 0.36±0.05 for W205, W365 and W550, respectively. During the first 20 years studied, the observed effective size was small. The generation intervals by gametic pathway were: 7.7±3.4 (sire-son), 7.8±3.7 (sire-daughter), 6.9±3.3 (dam-son), 6.8 ± 3.1 (dam-daughter), and mean interval of 7.3±3.4 years. The studied population showed moderate heritability coefficients, whereas the genetic gains based on the studied traits may be higher than those estimated by genetic tendencies. Reduced generation interval, increased effective size and continuous mating control of relatives are important strategies for the genetic progress of the Tabapuã breed in the region. <![CDATA[<b>Evaluation of milled pearl millet in the feeding of growing rabbits</b>]]> Two experiments were carried out in order to estimate the nutritional value and the performance of growing rabbits fed different levels of pearl millet (ADR 7010). In the digestibility trial, nutritional values of pearl millet were determined in 22 45-day-old New Zealand White rabbits, allotted in a completely randomized design, subjected to two treatments - a reference diet and a test diet with 70% of its volume composed of reference diet and 30% of pearl millet - and 11 replications. The apparent digestibility values of dry matter, crude protein, neutral detergent fiber and gross energy of the pearl millet were 88.7, 85.4, 24.4 and 75.0%, respectively. In the performance trial, 120 32-day-old New Zealand White rabbits were used. Rabbits were allotted in a completely randomized design and subjected to six treatments, with 10 replications and two animals for each experimental unit. The diets were formulated with increasing levels of pearl millet (20, 40, 60, 80 and 100%), substituting the corn in the reference diet, according to the digestible energy. No differences were observed in daily feed intake, daily weight gain, feed conversion, carcass traits and feed cost per kilogram of rabbit. Regardless of the amount of corn substituted, pearl can replace corn in diets for growing rabbits. <![CDATA[<b>Sources of organic trace minerals in diets for weaned piglets</b>]]> One hundred and twenty six piglets from a commercial genetic strain weaned at 21 days of age (6.11±0.42 kg) were used to evaluate the effects of supplementation levels of organic sources of trace minerals in the diets of weaned piglets on performance, occurrence of diarrhea, excretion of copper and zinc in the feces, and hematological parameters. A completely randomized block design was adopted, composed of six treatments (diets containing 100% of inorganic trace minerals premix at 3.00 kg/T; diets containing 0, 25, 50, 75 or 100% of organic trace minerals premix, equivalent to 0; 0.75; 1.50; 2.25 or 3.00 kg/T, respectively), seven replicates and three animals per plot. During the experimental period (from 21 to 63 days of age), the increasing levels of organic trace minerals premix in the diets determined a quadratic effect on daily weight gain (DWG), feed conversion (FC), percentage of hematocrit (Ht), hemoglobin (Hb), mean corpuscular hemoglobin (MCH), mean corpuscular volume (MCV), platelets (Pt), and a linear increase of Cu and Zn concentrations in feces. The comparison of means between the treatment with inorganic trace minerals premix and the other treatments showed that piglets fed diets without trace minerals premix had lower values of DWG, Ht, Hb, MCH, MCV, Pt and the worst FC value of piglets fed diets containing 25% of organic trace minerals premix presented lower values of Ht and Hb, in comparison with those fed diets with 100% of inorganic trace minerals premix. Inorganic trace minerals premix can be substituted by organic trace minerals premix at a lower level of inclusion in diets for weaned piglets. <![CDATA[<b>Reduction in the protein level and addition of oil in diets for finishing pugs under different temperatures</b>]]> The objective of this study was to evaluate the effect of reducing the crude protein (CP) with the use of amino acids in diets with the same amount of calories anddifferent levels of soybean oil (SO) for finishing pigs kept in two different ambient temperatures. A total of 120 barrows (initial weight of 68.0±1.9 kg) were utilized for the experiment. The design was of randomized blocks in a 2 × 3 × 2 factorial arrangement (two levels of CP, 16.2 and 13.7%; three levels of SO, 1.5; 3.0 and 4.5%; and two ambient temperatures, 19 and 31 ºC), totaling twelve treatments with five replicates for thirty days. The heat reduced feed intake (FI) of the animals, regardless of the levels of CP and SO used, and reduced weight gain (WG) in diets with reduced CP and SO or higher SO. The increased level of CP and SO improved feed conversion (FC) when the animals were kept in thermoneutral environment and given a diet with higher protein content. The reduction in CP increased FI only in the thermoneutral environment. In the heat, WG increased in diets with higher levels of SO, without influencing FC. The manipulation of diet and temperature did not affect most carcass traits. The SO reduced backfat thickness (BT) only in diets with high CP and animals kept in thermoneutral environment. The reduction of CP increased the BT only in diets with high content of SO, both in hot and thermoneutral environments. Heat reduces FI and the inclusion of SO does not improve performance or carcass characteristics in these conditions. The reduction in CP improves WG only in diets with high oil content; however, it increases BT. In thermoneutral environment, increasing the SO is beneficial for performance and carcass characteristics, except when diets with reduced CP are used. The reduction in CP improves performance only in diets with low oil content. <![CDATA[<b>Performance of broilers experimentally inoculated with <i>Salmonella </i>Typhimurium and fed diets with addition of lactulosis</b>]]> The objective of this experiment was to evaluate the influence of lactulose on performance as well as its ability to prevent colonization by Salmonella Typhimurium in broilers orally inoculated with this pathogen. The design adopted was completely randomized, with 630 one-day-old male chicks distributed into six treatments, with seven replications and 15 birds per experimental unit. The treatments comprised the following procedures: T1 (control group) - no S. Typhimurium inoculation or supply of lactulosis; T2 - only inoculation of S. Typhimurium; T3 - only lactulosis supply; T4 supply of lactulosis and S. Typhimurium inoculation on the first day of life; T5 - supply of lactulosis 48 hours before S. Typhimurium inoculation; and T6 - supply of lactulosis 48 hours after inoculation of S. Typhimurium. Performance variables were evaluated on the seventh, 14th, 21st and 28th days of age; fragments of the duodenum and jejunum were collected and sent to histomorphometric assessment at 14 days of age, and S. Typhimurium excretion was verified in cloacal swabs on the 10th, 24th and 35th days of age. Performance data were analyzed by ANOVA and Tukey's test (5%) and fecal excretion data were assessed by non-parametric chi-square test. Better weight gain and feed conversion were observed in groups fed lactulosis with or without challenge of S. Typhimurium up to 21 days of age. Reduced duodenum villous height was verified on the 14th day in groups challenged with the pathogen. Reduction of S. Typhimurium fecal excretion was verified in broilers fed lactulosis from the first day of life on and 48 hours before receiving S. Typhimurium directly into the crop. Lactulosis increases broiler performance up to one week after its inoculation, influences duodenum villous height and reduces the fecal excretion of Salmonella Typhimurium. <![CDATA[<b><i>In situ</i></b><b> and <i>in vitro</i> degradation kinetics and prediction of the digestible neutral detergent fiber of agricultural and agro-industrial byproducts</b>]]> The objective of this study was to evaluate the in situ and in vitro degradation kinetics and to predict the digestible neutral detergent fiber (dNDF) from the incubation times; in situ and in vitro degradation kinetic parameters; and equations fitted for agricultural and agro-industrial byproducts. Byproducts from pineapple, cocoa, palm kernel, corn gluten meal, common bean, sunflower, guava, cassava bark, cassava stems, cassava foliage, papaya, mango, passion fruit and turnips were evaluated. There were differences between the byproducts as for the potentially neutral detergent fiber (NDF) fraction and the in situ NDF degradation rate in the final volume of the gases generated by fibrous carbohydrates (FC), for the lag time and for the in vitro fractional degradation rate of the FC. There was equivalence between the dNDF values predicted in situ and those observed in vivo; however, there was low precision of estimates. The degradability in the in vitro incubation times of 30 and 48 hours presented equivalence with the values observed, but also did not present precision in the estimates. The equations fitted without lignin were not precise and accurate to estimate the dNDF of agricultural and agro-industrial byproducts. The equation with lignin and with the digestion rate obtained by the in vitro method presented more precise estimates. Byproducts from common bean, cassava bark and papaya presented greater NDF availability, whereas those of guava had the lowest NDF availability. The digestible NDF fraction was best predicted with the in situ incubation time of 72 hours. The equation fitted utilizing in vitro or in situ digestion rates enables the prediction of the NDF availability of agricultural and agroindustrial byproducts. <![CDATA[<b>Estimation of endogenous contribution and urinary excretion of purine derivatives from the total digestible nutrient intake in Nellore heifers</b>]]> The objectives of this experiment were to estimate the endogenous excretion of purine derivatives (PD), the intake and digestibility of nutrients, the urinary excretion of PD from the intake of total digestible nutrients (TDN) and digestible organic matter (DOM) in Nellore heifers. Eight heifers, 267±17 kg body weight (BW), were assigned to two 4 × 4 latin squares. The planned treatments were four dry matter intake (DMI) levels: 10, 14, 18 and 22 g/kg BW. The diet contained 70% corn silage and 30% concentrate. The endogenous losses were obtained by regression between excretion of PD (mmol/BW0.75) and DMI (g/BW0.75). When PD excretion (mmol/d) was related to the intake of DOM and TDN (kg/d), the following equations were obtained: ŶPD= 32.98 + 21.94*DOM and ŶPD= 32.47 + 20.40*TDN, respectively. The excretion of PD (mmol/d) was a function of DMI (kg/d): ŶPD = 0.605 + 0.014 x (r² = 0.46), and 0.60 mmol/BW0.75 was the endogenous fraction of PD. The endogenous losses of PD and nitrogen compounds obtained when the animals were fasted for 5 d, with free access to water, were 0.332 mmol/BW0.75 and 0.384 gN/BW0.75, respectively. The net protein requirement for maintenance was estimated at 2.4 g/BW0.75. Creatinine excretion is not affected by feed restriction. <![CDATA[<b>Prediction of non-carcass components in cattle</b>]]> This study was conducted to develop equations to predict chemical composition of head, limbs, hide and blood in cattle. A database containing 335 animals from 10 trials, with 221 Nellore, 38 Nellore-Simmental and 76 Nellore-Angus (96 steers, 118 heifers and 121 bulls) animals was used. Models were constructed to estimate water, ether extract (EE), crude protein (CP), ash and macrominerals (calcium, phosphorus, magnesium, sodium and potassium) in the non-carcass parts of cattle. A stepwise procedure was conducted to determine the most significant variables within each model. Subsequently, a random coefficient model was used to construct the equation using studies as random effect, and sex and breed as fixed effects. The visceral fat was the most important variable in the prediction models developed, affecting EE and water in head and limbs; head CP; and hide and blood water. Carcass dressing affected head EE and water and water in the limbs. Carcass weight had significant influence on head CP and hide EE; it was also affected by hide percentage in empty body weight (EBW). The percentage of OV in EBW influenced hide water. Lastly, EBW had influence only on hide sodium. Sex affected the EE of head and limbs. No breed effect was observed on any of the equations obtained. The estimation of the composition of head, limbs, hind and blood is possible and recommended, once they do not have great relevance to the estimation of EBW composition. <![CDATA[<b>Sensory profile of warmed-over flavour in tenderloin from steers supplemented with alpha-tocopherol</b>]]> The objective of the present study was to evaluate the occurrence of warmed-over flavour (WOF) in cooked tenderloin and the influence of alpha-tocopherol on its inhibition. A total of 24 animals were confined, 12 of which received 1200 mg/head/day of alpha-tocopherol acetate for 90 days. Longissimus dorsi muscle cuts (tenderloin) were obtained for sensory profile assessment by nine trained tasters. The tasters evaluated the taste of the meat based on four general and 18 specific attributes. The results of the evaluations were analysed with ANOVA, post-hoc tests of the means (Tukey tests), and principal component analysis (PCA). There was no significant difference in the WOF between the cuts of meat from the supplemented and non-supplemented animals. However, as the refrigeration period increased, there was a decrease in the intensity of the umami and sweet taste attributes and the flavour and aroma of the roast meat as well as an increase in the intensity of the oxidised vegetable oil flavour and the aromas of fish, hard-boiled egg, flaxseed oil, and oxidised vegetable oil. The samples that had been stored for one day were characterised by PCA as having sweet and umami tastes and the flavour and aroma of roast meat, whereas after three days, the samples were classified as having sour and bitter tastes, the flavour of chicken and nuts, and the aroma of fish. The typical sensory attributes desirable for roasted meat decreased in intensity during the three days of storage after cooking, whereas the intensity of unpleasant (oxidative) attributes for the consumer increased. <![CDATA[<b>Behavior pattern of beef heifers supplemented with different energy sources on oat and ryegrass pasture</b>]]> The objective of this study was to evaluate behavior patterns of heifers grazing on black oat (Avena strigosa Schreb.) and ryegrass (Lolium multiflorum Lam.), fed supplementation with brown rice meal and/or protected fat. A total of 28 Charolais × Nellore crossbred heifers at average initial age of 18 months and with initial live weight of 274.9±4.97 kg were used in the experiment. Animals were kept in oat + ryegrass pastures and distributed in the following treatments: no supplementation; Megalac (MEG): protected fat supplementation; supplementation with brown rice meal (BRM); and supplementation with BRM + MEG. The neutral detergent fiber (NDF) intake of pasture either in kg or in percentage of live weight was not changed by supply of supplement, but increased linearly (0.045 kg per day) over grazing periods. Supplementation with BRM and BRM + MEG reduced grazing time, 49.63%, in relation to non-supplemented animals and animals supplemented with MEG, 63.13%. Feeding seasons per minute increased over the experimental period with reduction in time spent in each feeding station. The number of bites per feeding station decreased linearly, with a variation of 34.48% in the late grazing period. Heifers supplemented with BRM and BRM + MEG require less time for grazing and increase their idle time, with no modification in displacement patterns within the paddocks and pasture ingestion. Grazing and idle time does not change in the distinct periods of pasture use, but rumination time increases with days of pasture use and with increase in NDF intake. <![CDATA[<b>Production parameters and forage loss of oat and rye grass pastures managed with beef heifers fed diets with energy supplementation</b>]]> Production parameters of intercropped pastures of oat and rye grass managed with beef heifers supplemented with brown rice meal and/or protected fat were evaluated. Twenty-eight Charolais × Nellore crossbred heifers at initial average age of 18 months and initial average live weight of 274.9 kg were utilized in the experiment. Animals were kept on oat + rye grass pastures and distributed in the following treatments: no-supplementation (NS): heifers kept only in pastures; Megalac (MEG): supplementation with protected fat; brown rice meal (BRM): supplementation with BRM; BRM + MEG: supplementation with BRM plus protected fat. The greater participation of oat leaf was from July 5th to August 10th, 2009 and of rye grass, from August 30th to September 26th, 2009. The crude protein content increased until the 55th day (225.1 g/kg). Pasture total digestible nutrients presented a cubic behavior, with an average of 722.0 g/kg. The highest supply of leaf blades, 5.17 kg of dry matter/100 kg of live weight, was found in the second period. Pasture intake increased throughout the periods. Forage mass and support capacity of the animal did not differ between treatments, presenting means of 1245.02 kg of dry matter/ha and 882 kg of live weight/ha, respectively. Stoking rate, forage loss and pasture intake were not affected by the treatments. Supplementation of beef heifers with rice meal and/or protected fat did not change production parameters of oat + rye grass pastures or pasture intake. Increase in daily accumulation rate of dry matter and supporting capacity of the animals increases forage losses. <![CDATA[<b>Heifer Retention Program in the Pantanal</b>: <b>a study with data envelopment analysis (DEA) and Malmquist index</b>]]> The objective of this study was to propose Data Envelopment Analysis (DEA) models and non-parametric Malmquist indexes to evaluate the efficiency of 11 livestock farms in the Pantanal region. These farms took out a loan from 'Fundo Constitucional de Financiamento do Centro-Oeste' - FCO (Constitutional Financial Fund for the Midwest), a line of credit for financing heifer retention. The beneficiaries were the farmers whose properties met the following conditions: farms located in the plain of Pantanal, with at least 50% of native pasture; farms that were part of managerial capacity building projects intended to ensure better management and animal performance indexes; and farms with pasture areas where the activity could potentially evolve. The management of the loan on 11 farms were studied in relation to the technology introduced in the period from 2004 to 2008. Five properties presented technical efficiency below 1, that is, the technical management efficiency with the objective to increase the cattle through heifer retention and the purchase of higher genetic quality heifers was not achieved. However, the index of technological progress was above 1 on all tested farms, which means that technology was in fact incorporated in all properties, which resulted in total factor productivity growth on all farms. The main objective was fully met, even on the technically inefficient farms. <![CDATA[<b>Technical performance of milk producers in the state of Goiás , Brazil, in the short and long terms</b>]]> The objective of this study was to identify groups of technologically homogeneous milk producers in the State of Goiás and calculate the gains for inefficient producers, considering the ones of better performance (benchmarks) with the same technological level, i.e., in the short term, and the benchmarks in higher technological level, i.e., in the long term. Multivariate statistical analysis techniques were used for the formation of homogeneous producer groups and multi-stage model of data envelopment analysis (DEA) for the estimation of efficiency scores and identification of benchmarks. The results indicated the formation of four groups of producers and indicate that, on average, the dairy farming in Goiás presents mainly characteristics of traditional, less specialized production. Estimated average efficiency for producers as a whole, or efficiency of long-term, was 0.571. The short-term results vary according to the group analyzed, but were higher than the long-term values, indicating that the factor analysis promoted technological homogeneity between the producers of the same group. Results showed a trend in dairy farming of Goiás towards adequacy of the input/output ratio to the standards of less capitalintensive production systems. <![CDATA[<b>Locomotion problems of broiler chickens and its relationship with the gait score</b>]]> The objective of this study was to evaluate the correlation between the ability to walk (gait score), incidence of femoral degeneration, tibial dyschondroplasia, valgus and varus deformity and leg symmetry of broiler chickens. Male chickens of the Cobb strain from a commercial poultry farm were utilized in this experiment. Fifty 35 and 42-day-old birds were evaluated according to the gait score and valgus or varus incidence. To assess the bilateral symmetry and the lesion score for femoral degeneration and tibial dyschondroplasia, broilers were weighed and euthanized for the removal of the femur and tibia of both legs. The lesion scores for femoral degeneration and tibial dyschondroplasia, varus or valgus deformity, bone symmetry and gait scores of the chickens were then correlated. It was found that weight, age and the incidence of femoral degeneration and tibial dyschondroplasia are not always correlated with the gait score and that only valgus deformity is more correlated. <![CDATA[<b>Evaluation of cysteamine associated with different energy patterns in diets for broiler chickens</b>]]> This experiment was conducted with the objective of evaluating cysteamine (CS) supplementation in broiler chick diets with different energy density patterns. A total of 980 chicks of the Cobb 500 strain at one day of age were allocated into 28 plots. A completely randomized design in a 2 × 2 factorial arrangement, with 7 replications, was adopted. The factors under study were the supplementation (or absence) of cysteamine (60 mg/kg and 80 mg/kg of feed in the starter and growth/finishing phases, respectively) and two patterns of apparent metabolizable energy corrected by nitrogen balance (AMEn) in the diets. The energy levels (Mcal/kg of feed) practiced in pattern 1 were 3.00; 3.10; and 3.20, and for pattern 2, they were 3.05; 3.20; and 3.30 in the starter, growth and finishing phases, respectively. The diets were on the basis of corn and soybean meal with a feeding program with three diets. Feed intake, weight gain, feed conversion, feasibility and carcass yield were evaluated. There was no interaction between the CS supplementation and AME patterns in the diet upon the performance and/or carcass characteristic evaluated. Broilers fed the diet supplemented with CS presented improved feed conversion along the rearing cycle, but feed intake and weight gain were not affected by the supplementation of CS. The highest pattern of energy density (2) provided increased weigh gain in the starter phase of rearing and better feed conversion of the birds over the whole rearing period. The carcass yield was not influenced by the cysteamine supplementation and/or energy levels studied. <![CDATA[<b>Testicular echotexture and seminal quality of young Montana Tropical Compound bulls classified as sound and unsound for breeding</b>]]> The objective of this study was to investigate the relationship between testicular echotexture and seminal quality, in addition to evaluate the testicular parenchyma echogenicity pattern in young Montana bulls classified as sound and unsound for breeding. Fifty-two young Montana Tropical Compound bulls from 22 to 33 months of age were used. The animals were previously evaluated by breeding soundness evaluation and thereafter divided into two groups of breeding soundness classes: 1 = 16 animals sound for breeding; 2 = 36 animals unsound for breeding by means of physical and morphological analysis of semen. All animals underwent an ultrasound examination of the testes, and the images were analyzed with the software "Image J". ANOVA was used for statistical analysis, to determine the effect of groups in relation to testicular measurements, physical and morphological semen features and ultrasound pixel analysis. There was a difference between scrotal circumference between classes, with 39.7±2.1 cm and 37.3±3.1 cm for sound and unsound animals, respectively. Regarding testicular echotexture, mean values for the pixel intensity were 95.7 and 94.0 for sound and unsound animals for breeding, respectively, with no difference between the classes. None of the studied parameters were correlated with each other, indicating that the quantification of the pixel intensity in testicular echotexture was not effective in determining the degree of sexual maturity in Montana Tropical Compound bulls.