Scielo RSS <![CDATA[Revista Brasileira de Zootecnia]]> http://www.scielo.br/rss.php?pid=1516-359820170004&lang=es vol. 46 num. 4 lang. es <![CDATA[SciELO Logo]]> http://www.scielo.br/img/en/fbpelogp.gif http://www.scielo.br <![CDATA[Histopathological aspects of the liver of free-living and farmed bullfrogs (<em>Lithobates catesbeianus</em>)]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982017000400275&lng=es&nrm=iso&tlng=es ABSTRACT The objective of this study was to compare the histopathological aspects of the liver of free-living and farmed bullfrogs (Lithobates catesbeianus). Thirty liver samples were collected from young and adult bullfrogs in the states of Minas Gerais and Rio de Janeiro, Brazil. Marked blood congestion and even hemorrhage and a large number of melanomacrophages were observed in most of the livers from free-living bullfrogs. Additionally, hepatocytes showed cytoplasmic eosinophilia and some showed nuclear hypertrophy and presence of microvesicular steatosis; small foci of infiltrates of mononuclear cells were observed in some samples, as well as a thicker capsule. In the farmed bullfrogs, cytoplasmic rarefaction was normal. Morphologically, unlike the livers of animals reared on farms, the livers of free-living animals did not show any evidence of protein-mineral deficiency, characterized by cytoplasmic vacuolation and a larger number of melanomacrophages, suggesting greater aggression to the liver parenchyma, probably due to environmental toxicity. Free-living bullfrogs feed on proteins of better biological value, derived from animals preyed in the natural environment. <![CDATA[Effects of type of lesion and trimming on short-term behavior of grazing dairy cows]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982017000400280&lng=es&nrm=iso&tlng=es ABSTRACT This study aimed to investigate how type of hoof injury and corrective trimming alter the behavior of dairy cows. Thirty-four lactating Holstein and Jersey cows were used. They were scored for lameness score on days –2 and 6, before and after trimming and treatment, respectively, using a numerical rating system, in which 1 = perfect gait and 5 = severely lame, and had their postural and ingestive behavior evaluated on days –1 and 6 before and after trimming and treatment, respectively. Locomotion score was analyzed using t-paired test and behavioral data were analyzed by univariate variance analysis with cows as the experimental units, according to a completely randomized design with repeated measurements. Cows with infectious hoof diseases spent less time lying down and idling, but more time standing up and feeding at the trough than those with non-infectious hoof diseases. Locomotion score and the proportion of time spent standing decreased one week after trimming and treatment, while time spent lying down increased. Trimming plus treatment and type of hoof diseases do not change ingestive behavior but change postural behavior of dairy cows. <![CDATA[Recovery of a dystrophic Red Latosol (Oxisol) and pasture as a function of gypsum in the Cerrado biome]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982017000400286&lng=es&nrm=iso&tlng=es ABSTRACT This study was conducted to evaluate the chemical effects of gypsum on the soil and on the recovery of a pasture established with palisade grass (Urochloa brizantha) in a Cerrado biome region. A randomized block experimental design with six treatments and four replications was adopted. Treatments consisted of five levels of gypsum (0, 450, 900, 1800, and 3600 kg ha−1) plus an unmanaged control treatment (without gypsum or additional chemical fertilizers). The gypsum treatments received addition of fertilizer (200 and 40 kg ha−1 of N and P respectively). The soil treatment started in October 2012. The application of gypsum provided an increase in plant height, number of tillers, and dry matter of the shoots of palisade grass. Gypsum combined with chemical fertilizers provided an increase in productivity compared with chemical fertilizers alone. The use of gypsum improved the chemical characteristics of the soil, increasing calcium and sulfur in the deeper layers, consequently, providing greater development of the palisade grass root system. High gypsum levels impaired the development of the root system, especially in the 0.20–0.40 m layer. Gypsum provides recovery of soil and degraded pastures. <![CDATA[Genetic variability of the components of seed yield in interspecific hybrids of <em>Paspalum</em>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982017000400296&lng=es&nrm=iso&tlng=es ABSTRACT This study aimed to determine the variability and expression of the components of seed yield in twenty-three apomictic Paspalum plicatulum × Paspalum lepton hybrids and two male parent plants (P. lepton). We used a randomized block design with genotypes individually arranged into ten blocks. The variables were: number of total tillers/plant, number of vegetative tillers/plant, number of reproductive tillers/plant, percentage of reproductive tillers, number of racemes/inflorescence, number of seeds/inflorescence, weight of a thousand seeds, and seed yield. We assessed genetic variability using multivariate procedures: generalized Mahalanobis distance, Tocher's clustering optimization method, and quantification of the relative contribution of the variables. The quantification of variability, based on the components of seed yield of Paspalum plicatulum × Paspalum lepton hybrids, allows the formation of six groups of genotypes using Tocher's method, with high means for the characteristics studied. Weight of a thousand seeds and number of seeds/inflorescence were the traits that most contributed to the genetic dissimilarity. Genetic crosses involving genotype 10E5052 from group VI and 10E4071 from group V could be undertaken to isolate high yielding segregants, since these genotypes have high seed yielding potential. <![CDATA[Genetic parameters of age at first calving, weight gain, and visual scores in Nelore heifers]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982017000400303&lng=es&nrm=iso&tlng=es ABSTRACT This study aimed at estimating the heritability of age at first calving and of performance traits included in the selection index and the genetic correlations between age at first calving and these performance traits. Data were extracted from the Conexão Delta G database and only data from herds in which heifers were bred younger than 24 months of age were used, resulting in a file with 331,310 evaluated animals. The following traits were included in the analyses: age at first calving, birth to weaning gain, post-weaning weight gain, visual scores of conformation, precocity, and muscling evaluated at weaning and in yearling heifers. Covariance components were obtained by bi-character analyses between traits. An alternative age at first calving was also taken into account, in which all heifers were used, including those that were mated and did not calve. Covariance components and estimates of the effects included in the model were obtained using the software program DMU. Heritability estimates were 0.11 and 0.13 for age at first calving and alternative age at first calving, 0.38 for birth to weaning gain, and 0.13 for post-weaning weight gain. Visual score estimates ranged between 0.16 and 0.18 at weaning and 0.19 and 0.29 in yearlings. Genetic correlation estimates of the traits were low, but in the desirable direction. Selection for birth to weaning gain and visual scores does not have a negative effect on age at first calving or alternative age at first calving. <![CDATA[Associations among growth, scrotal circumference, and visual score of beef cattle in performance tests on pasture or in feedlots]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982017000400309&lng=es&nrm=iso&tlng=es ABSTRACT This study aimed to evaluate associations among final weight (FW), average daily gain (ADG), scrotal circumference (SC), and visual score (VS) of beef cattle in performance tests on pasture or in feedlots. Genetic parameters for FW, ADG, SC, and VS of young Nellore bulls performance-tested on pasture or in feedlots were evaluated by mixed model. The performance test and final age were considered as fixed effects and additive genetic and residual effects were considered as random effects. Additive genetic and residual variances for final weight and average daily gain were smaller on pasture than in feedlots. There was no difference between genetic and residual variances and heritability for scrotal circumference on pasture or in feedlots. Genetic variance and heritability for visual score on pasture were smaller than those in feedlots. The posterior means (and highest posterior density intervals with 90% of samples (HPD90) in parentheses) for heritability were 0.46 (0.42; 0.50) and 0.49 (0.41; 0.55) for FW, 0.25 (0.22; 0.29) and 0.25 (0.19; 0.30) for ADG, 0.56 (0.51; 0.61) and 0.60 (0.51; 0.68) for SC, and 0.31 (0.27; 0.34) and 0.42 (0.36; 0.48) for VS on pasture or in feedlots, respectively. The genetic correlations (posterior means with HPD90 in parentheses) were 0.74 (0.69; 0.79) and 0.67 (0.58; 0.77) between FW and ADG; 0.49 (0.43; 0.55) and 0.60 (0.53; 0.68) for FW and SC; 0.79 (0.75; 0.83) and 0.85 (0.80; 0.90) for FW and VS; 0.37 (0.29; 0.46) and 0.34 (0.19; 0.50) for ADG and SC; 0.65 (0.59; 0.71) and 0.74 (0.64; 0.84) for ADG and VS; and 0.46 (0.39; 0.52) and 0.53 (0.44; 0.62) for SC and VS, obtained on pasture or in feedlots, respectively. The genetic and residual (co)variances of growth, scrotal circumference, and visual score of beef cattle vary across environments; however, genetic and residual correlation and efficiency of correlated response among these traits remain constant on pasture or in feedlots. <![CDATA[Biometry and ultrasound evaluation of testicles and accessory glands in Santa Ines rams]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982017000400317&lng=es&nrm=iso&tlng=es ABSTRACT This work aimed to investigate the relationship between echogenicity, testicular biometry, and accessory gland biometry and evaluate the echogenicity pattern of these structures in Santa Ines rams. Fifty-four healthy Santa Ines sheep were classified into three age groups: group 1 - 3 to 5 months (pre-pubertal); group 2 - 7 to 11 months (pubertal); and group 3 - 13 to 28 months (sexually mature). The averages of testicular biometry and bulbourethral gland biometry were different among age groups. The testicular parenchyma was homogeneous with low echogenicity (pre-pubertal group) and medium echogenicity (pubertal and sexually mature groups), suggesting that testicular echogenicity can be a helpful tool to identify the start of puberty. The accessory glands were heterogeneous with low echogenicity in all age groups. Correlations were high between weight, biometry of testis and of bulbourethral gland and echogenicity of the accessory glands, indicating that sexually mature rams with higher body development have larger testicles and larger glands. We recommend the use of testicular biometry as a complementary evaluation of the reproductive efficiency of Santa Ines rams. The average values of echogenicity and the biometry of accessory glands are important parameters to assist the selection of breeding rams. <![CDATA[Substitution of blood plasma with soy protein concentrate in piglet diet]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982017000400324&lng=es&nrm=iso&tlng=es ABSTRACT In this study, we evaluated the effects of substitution of partial and total spray-dried blood plasma (BP) with soy protein concentrate (SPC) in the diet of post-weaning piglets on their performance, intestinal histomorphometry, and blood parameters. Fifty-four castrated male piglets, weaned at an average age of 21 days and an initial average weight of 7.01±0.294 kg, were distributed in a completely randomized block design, with three diets (0%SPC-5%BP, 2.5%SPC-2.5%BP, and 5%SPC-0%BP), six replicates, and three piglets per experimental unit. The experimental feeds were formulated to meet the requirements of the piglets at 21-32 and 33-42 days of age (pre-starter diet) and 43-66 days of age (starter diet). From 21 to 32 and 21 to 42 days of age, daily feed intake, daily weight gain, and final weight of the animals were higher in the group fed 2.5%SPC-2.5%BP and 0%SPC-5%BP. From 21 to 66 days of age, daily weight gain and daily feed intake were higher in the animals fed 2.5%SPC-2.5%BP. No effect was observed on the histomorphometry variables. The total leukocyte count was higher in animals fed 2.5%SPC-2.5%BP and 5%SPC-0%BP and the lymphocyte count was lower in the piglets that received 0%SPC-5%BP. The combined use of soy protein concentrate and spray-dried blood plasma in the feeds of piglets between 21 and 42 days of age improves their productive performance. <![CDATA[Carcass traits and short-chain fatty acid profile in cecal digesta of piglets fed alfalfa hay and fructooligosaccharides]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982017000400331&lng=es&nrm=iso&tlng=es ABSTRACT The objective of this study was to evaluate the effects of the addition of the prebiotic fructooligosaccharide and/or alfalfa hay to piglet diets on carcass traits and short-chain fatty acid profiles in the cecal digesta. Seventy-two commercial crossbred piglets of both sexes, with an average initial weight about 6 kg and age of approximately 21 days, were distributed in a randomized block design, using a factorial scheme, which consisted of three alfalfa hay levels (0, 5, and 10%) and two fructooligosaccharide levels (0 and 0.3%). Fiber addition in the presence of the prebiotic exerted an effect on cecal digesta short-chain fatty acid, increasing the acetic and reducing the butyric acid concentrations. The meat quality was also affected by the treatments, water activity, water-holding capacity of meat, and especially the reduction of fat content and the increase of moisture. The treatments did not affect the pH and the ammonia content in the cecal digesta. Most carcass traits were not affected by the treatments, except for carcass weight and backfat thickness in points 1 and 2, that decreased with the inclusions of fiber and prebiotic. The addition of 5% alfalfa hay improves carcass and meat traits in growing pigs without any change in carcass weight, demonstrating the advantage of using this ingredient to obtain a healthy final product to the customers. <![CDATA[Seasonal variation, method of determination of bovine milk stability, and its relation with physical, chemical, and sanitary characteristics of raw milk]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982017000400340&lng=es&nrm=iso&tlng=es ABSTRACT The objective of this research was to determine the variation of milk stability evaluated with ethanol, boiling, and coagulation time tests (CTT) to identify milk components related with stability and verify the correlation between the three methods. Bulk raw milk was collected monthly at 50 dairy farms from January 2007 to October 2009 and physicochemical attributes, somatic cell (SCC), and total bacterial counts (TBC) were determined. Milk samples were classified into low, medium, and high stability to ethanol test when coagulation occurred at 72 °GL, between 74 and 78 °GL, and above 78 °GL, respectively. Univariate analysis was performed considering the effects of year, months, and interaction in a completely randomized design. Principal factor analysis and logistic regression were done. There was an interaction between months and years for stability to the ethanol test and coagulation time. All samples were stable at the boiling test. Boiling test was not related to ethanol and coagulation time tests. Coagulation time was weakly but positively correlated with ethanol test. Broken line analysis revealed that milk stability measured with CTT and ethanol tests decreased sharply when SCC attained 790,000 or 106 cell/mL of milk, respectively. Milk stability measured with ethanol test decreased when TBC was higher than 250,000 cfu/mL, while there was no inflexion point between TBC and stability measured with CTT. Milk with high stability presented lower values for acidity, TBC, and SCC but higher values for pH, lactose, protein, and CTT compared with low-stability milk. Due to the execution easiness, single-point cut-off result and low cost, we do not recommend the replacement of ethanol test for boiling or coagulation time test. <![CDATA[Effect of calcium propionate and monensin on <em>in vitro</em> digestibility and gas production]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982017000400348&lng=es&nrm=iso&tlng=es ABSTRACT An evaluation of the effects of monensin and calcium propionate on the in vitro kinetics of gas production, digestibility, carbon dioxide, and minor gas production on different days was performed using the ruminal fluid from eight Suffolk lamb donors, after receiving additives for 1, 10, and 20 days. Treatments consisted of a control ration of 40% grain; 30 mg/kg of monensin in a diet with 40% grain; 10 g/kg calcium propionate in a diet with 30% grain; and the combination of both additives in a diet with 30% grain. The gas production was measured up to 72 h of incubation and all incubation procedures were repeated three times on days 1, 10, and 20. On incubation day 20, the volume and production of methane and minor gases were measured. There was an interaction between calcium propionate and monensin for maximum gas production, in vitro dry matter digestibility (IVDMD), carbon dioxide, and minor gases. Monensin reduced gas production on days 1 and 20, whereas calcium propionate increased gas production (Vm) on day 1. The rate of gas production (s) was reduced by calcium propionate on day 1 and by the combination of additives on day 10. Lag time was reduced by monensin on day 10; however, it declined linearly with the feeding time of the additives. Monensin had no effect on IVDMD (62.29 vs. 62.24%), while calcium propionate increased the IVDMD (60.00 vs. 64.53%). The inclusion of monensin increased CO2; however, the combination of monensin and calcium propionate had no effect on CO2 production. Monensin reduced methane (25.37 vs. 20.29%) and increased CO2. None of the additives showed consistent effects on the kinetic parameters of in vitro gas production over time. The treatments with monensin and calcium propionate showed a significant reduction in methane production, with a higher fermentation efficiency since the IVDMD was increased. Both additives are a strategy to consider to reduce methane emissions without affecting the ruminal fermentation. <![CDATA[Relevance of brands and beef quality differentials for the consumer at the time of purchase]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982017000400354&lng=es&nrm=iso&tlng=es ABSTRACT The objective of this study was to identify the purchase habits and preferences of beef consumers, their level of knowledge on brands and products with quality differentials (certifications, packaging, premium lines), and the relevance of different attributes in the purchase decision, and to group consumers according to the profile of purchase decision. The methodology consisted of using an information-collecting instrument applied to 271 beef consumers. The data collected were analyzed using descriptive statistical analyses, chi-square analysis, and correspondence analysis, relating socio-demographic profile of the respondents with the other variables collected. Chi-square and correspondence analyses showed that younger consumers with lower levels of income and education are influenced by posters and advertisements at the point of sale, unaware of differentiated and branded products, and that they do not choose branded beef at the time of purchase. Consumers over 60 years showed a more conservative purchase profile, with no influence. The most valued attributes are appearance, price, and type of cut, being brand and certifications little relevant as tools to help decide the product purchase.