Centro de Ciências Agrárias
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Item Reproductive losses in beef cattle rearing on extensive system production: effects of genotype and parity(Brazilian Journal of Animal Science, 2024-10) Vivián Paradizo, Rodrigo; Pérez-Clariget, Raquel; Espasandin, Ana CarolinaWe evaluated the reproductive losses in three periods: period I - starting from the time the cows were exposed to the bulls to pregnancy diagnoses (PD, number of cows diagnosed as non-pregnant/total exposed cows × 100); period II - from the time of PD to calving (number of calving cows/number of cows diagnosed as pregnant × 100); and period III - from calving to weaning (number of weaned calves/number of calving cows × 100) in purebred Hereford (HH) and Angus (AA) cows and their crosses in beef cows under extensive production systems. Likewise, the effect of parity (nulliparous, primiparous, and multiparous) and the interaction between both factors were studied. A thirteen-year data set (2505 record) of an experimental breeding herd, maintained in an extensive production system based on natural grassland, was used. The dataset was under a complete diallel design between HH and AA breeds. Both the genetic group and parity of the cow affected the reproductive losses, but only in period I. No interaction was found. Purebred cows had higher reproductive losses than the crossbred cows, without differences between the purebred (HH and AA) or between the crossbred (AH and HA). The greatest losses were observed rather in primiparous than in nulliparous and multiparous cows without difference between the latter two. The use of crossbred cows in extensive production systems is an alternative to reduce reproductive losses and to increase calf harvestItem Evaluation of the use of probiotic (Bacillus subtilis C-3102) as additive to improve performance in broiler chicken diets(Brazilian Journal of Animal Science, 2012-11) Nunes, Jaqueline Oliveira; Bertechini, Antonio Gilberto; Brito, Jerônimo Ávito Gonçalves de; Fassani, Édison José; Mesquita, Fabrício Rivelli; Makiyama, Letícia; Meneghetti, CamilaThe objective of this experiment was to evaluate the use of probiotic based upon Bacillus subtilis C-3102 (BS) in broiler diets containing or not conventional additive growth-promoter (AGP). A total of 1,824 one-day-old chicks of the Cobb-500 strain were used and distributed into 48 plots (1.50 × 2.00 m). A completely randomized design with four treatments and 12 repetitions was adopted. The treatments evaluated were: 1- Negative Control - AGP-free diet (NC); 2 - Positive Control, with AGP halquinol 30 mg/kg diet (PC); 3 - NC + BS (3x105 cfu/g diet); and 4 - PC + BS (3x105 cfu/g diet). The diets were on corn, soybean meal and meat and bone meal basis, formulated according to the nutrient allowances of the Strain Cobb Guide, following a feed program with three diets (starter, grower and finisher). At 21 and 42 days of age, feed intake, weight gain and feed conversion were evaluated, and carcass yield characteristics were determined at 42 days of age. Throughout the trial period (starter and total phases), better feed conversion was found for broilers fed diet with both additives (AGP and BS) combined. At the end of the experiment (1 to 42 days), the highest weight gain also occurred in broilers fed diets with a combination of the two additives. In present study, the use of BS or AGP alone in diets did not affect the performance of broilers. The carcass yield was not influenced by the use of the additives and beneficial effects of supplementation of BS and AGP combined in the diet on broiler performance were observed.Item Aerobic fungi in the rumen fluid from dairy cattle fed different sources of forage(Brazilian Journal of Animal Science, 2012-11) Almeida, Patrícia Natalicia Mendes de; Duarte, Eduardo Robson; Abrão, Flávia Oliveira; Freitas, Cláudio Eduardo Silva; Geraseev, Luciana Castro; Rosa, Carlos AugustoThe objective of this study was to evaluate the aerobic microbiota of the rumen fluid from Holstein cows and heifers fed different tropical forage in the north of Minas Gerais, Brazil. A total of 30 samples of rumen fluid from cows fed with sorghum silage were collected: 32 from cows fed Brachiaria brizantha, 12 from heifers that received sorghum silage and 11 from calves fed sugar cane foliage. The culture was carried out using the agar Sabouraud medium and the solid C medium, containing microcrystalline cellulose. The isolated mycelial fungi were identified by microculture technique and yeasts by micromorphological and physical-chemical analysis. Specific identification for yeasts was confirmed by ribosomal DNA sequence analysis. The presence of fungal colonies was confirmed on the Sabouraud medium for 100% of the samples. No significant differences were observed comparing the concentrations of mycelia fungi in the rumen fluid from cows fed different forages and for the two categories evaluated, fed sorghum silage. Yeast populations in the rumen fluid from heifers fed sugarcane were higher compared with those receiving sorghum silage. The yeast Pichia kudriavzevii (Candida krusei) was the most frequent and among the mycelial fungi, the genus Aspergillus was the most frequently observed, corresponding to 56% of the samples. Future studies should elucidate the variations in the populations of these microorganisms considering the carbohydrate sources in the tropical forages and the animal categories. The ecological or pathogenic role of these microorganisms should also be considered, aiming at improved productivity and health of cattle.Item Meat sheep farming systems according to economic and productive indicators: a case study in Southern Brazil(Brazilian Journal of Animal Science, 2021-06) Debortoli, Elísio de Camargo; Monteiro, Alda Lúcia Gomes; Gameiro, Augusto Hauber; Saraiva, Livia Cristina Vale FidalgoThis study aimed to characterize 24 representative sheep production farms from five mesoregions in the state of Paraná, Southern Brazil, so that economic and productive improvement strategies could be proposed. The representative farms for each region were defined at meetings with sheep farmers and technicians via the rapid appraisal methodology and represent 65% of the state’s flock. The information of each representative farm was collected between March 2015 and February 2016. Principal component analysis was used to verify the relationships among the different variables that characterized the farms. These characteristics were: number of ewes (V1), total cost per kilogram of revenue-generating product (V2), feeding costs (V3), labor costs (V4), facility and equipment depreciation costs (V5), and gross margin in the production cycle (V6). Cluster analysis was performed, resulting in three distinct groups: one including eight, another seven, and the third, nine farms. The results aided in classifying the farms into groups with similar characteristics, such as production scale, reproductive efficiency, technical and managerial control, appreciation of cooperatives, and availability of continuous technical assistance. The production scale, reproductive and productive efficiency, adoption of technologies, and cooperative organizational structure can be emphasized as positive performance benchmarks and were the most important aspects to achieve positive economic results.Item Estimation of genetic parameters for weaning and yearling weights in a composite population used to form the Purunã breed(Brazilian Journal of Animal Science, 2021-06) Otto, Pamela Itajara; Santos, Alexandre Leseur dos; Perotto, Daniel; Oliveira, Sheila Nogueira de; Granzotto, Fernanda; Gobo, Diego Ortunio Rosa; Souza, Felipe Eduardo Zanão de; Thomazini, GuilhermeWe aimed to evaluate the effects of sex and the linear and quadratic components of age of dam at calving, as well as apply a mixed model including maternal effect for the genetic evaluation of weaning (WW) and yearling (YW) weights. The phenotypic database was composed by Charolais, Caracu, Aberdeen Angus, and Canchim purebred and crossbred animals. Single-trait analyses were performed using models that included the maternal effect for WW and YW traits, and a model ignoring this effect on YW (YWNM). The Deviance Information Criterion (DIC), model posterior probabilities (MPP), accuracy of breeding values (ACC), and Spearman’s rank correlation were applied to compare the models including and ignoring the maternal effect on YW. Sex and age of dam at calving had significant effects on WW and YW. The direct heritability estimates were 0.21±0.03 and 0.05±0.02, and the maternal heritabilities were 0.11±0.02 and 0.02±0.01 for WW and YW, respectively. The heritabilities estimated for YW may have been influenced by the several genetic groups in the population and by used conventional animal model, which may not have been the better fit model to evaluate YW in this population. The DIC, MPP, and ACC values indicated that YW outperformed the YWNM model, but the rank correlation and percentages of individuals selected in common suggested that the best animals would be selected independently of the model chosen.Item Lactose and milk urea nitrogen: fluctuations during lactation in Holstein cows(Brazilian Journal of Animal Science, 2014-09) Henao-Velásquez, Andrés F.; Múnera-Bedoya, Oscar David; Herrera, Ana Cristina; Agudelo-Trujillo, Jorge H.; Cerón-Muñoz, Mario FernandoThe objective of this study was to evaluate lactose and milk urea nitrogen (MUN) in milk from Holstein cows and their relationship with days in milk (DIM), milk yield, milk fat, milk protein, and somatic cell count (SCC). A total of 1,034 records corresponding to morning and afternoon milkings of 148 Holstein cows were used. Records were taken from 16 herds located in the Northern and Eastern dairy regions of Antioquia (Colombia). The curves were fitted using a generalized additive mixed model with smoothed estimates to find the best smoothing intensity factors involved in MUN and lactose concentration. Regarding MUN, the contemporary group effect was highly significant, but the parity effect was not significant. The DIM, lactose and milk fat smoothed covariates were highly significant, while milk yield and fat and SCC showed no statistical difference. Regarding lactose content, the contemporary group effect was highly significant, while the parity effect was not significant. Days in milk, MUN, milk fat, milk protein, and afternoon-milking SCC smoothed covariates were highly significant, while milk yield and morning-milking SCC were not significant. Lactose and milk urea nitrogen concentrations are affected by various factors throughout lactation, mainly by days in milk.Item Mineral mixtures from solid salt residues for lambs(Brazilian Journal of Animal Science, 2014-09) Manera, Daniel Bomfim; Voltolini, Tadeu Vinhas; Menezes, Daniel Ribeiro; Araújo, Gherman Garcia Leal deThe objective of this study was to evaluate water, mineral, feed and nutrient voluntary intakes, in addition to dry matter and nutrient digestibility and the nitrogen balance of lambs fed three mineral supplements. The first treatment consisted of solid salt residue (SSR) from an aquaculture tank; the second contained SSR from desalination waste; and the third treatment was control, which corresponded to the supplementation of a commercial mineral supplement. The study lasted 20 days, the first 15 of which were used for animals to adapt to the pens and diets, and the last five days were used for data collection. Twenty-four castrated male lambs with a body weight of 19.72±2.52 kg were utilized in the experiment. The mineral supplements evaluated did not affect the intake and digestibility of the dry matter and nutrients, the water and mineral-salt intake or nitrogen balance. Mineral supplements produced from the SSR from aquaculture tanks and from the desalination waste did not reduce feed, nutrient and water intakes or nutrient digestibility, which suggests that these raw materials can be used in the elaboration of mineral mixtures for lambs.Item Resíduo úmido de cervejaria na alimentação de cabras(Brazilian Journal of Animal Science, 2010-07) Silva, Veridiana Basoni; Fonseca, Carlos Elysio Moreira da; Morenz, Mirton José Frota; Peixoto, Eduardo Lucas Terra; Moura, Elisabeth dos Santos; Carvalho, Isabel das Neves Oiticica deObjetivou-se avaliar o efeito da substituição do concentrado pelo resíduo úmido de cervejaria sobre o consumo e a digestibilidade dos nutrientes em cabras. Foram utilizadas cinco cabras mestiças Boer × Saanen e cinco cabras Saanen distribuídas em dois quadrados latinos 5 × 5. As dietas foram compostas de 40% de feno de capim-tifton e os 60% restantes foram compostos de 0, 25, 50, 75 ou 100% de resíduo úmido de cervejaria em substituição ao concentrado. Os consumos de matéria seca (MS), matéria orgânica (MO), proteína bruta (PB), extrato etéreo (EE), carboidratos totais (CT), nutrientes digestíveis totais (NDT) e fibra em detergente neutro (FDN) ajustaram-se ao modelo quadrático, de modo que os maiores valores foram observados para as dietas sem resíduo úmido de cervejaria e com 25% desse resíduo. Os níveis de resíduo úmido de cervejaria tiveram efeito linear decrescente na digestibilidade aparente de matéria seca, matéria orgânica e carboidratos totais e efeito quadrática na digestibilidade da proteína bruta. O resíduo úmido de cervejaria pode ser utilizado em níveis de até 25% como substituto ao concentrado em dietas para cabras no final da lactação.Item Dissecting the genetic architecture of complex traits and its impact on genetic improvement programs: lessons learnt from the Virginia chicken lines(Brazilian Journal of Animal Science, 2010-07) Pettersson, Mats E.; Carlborg, ÖrjanLong-term selection experiments provide a valuable resource for understanding the genetic changes that take place in animal improvement programs. The Virginia chicken lines have for more than 50 years been subjected to singletrait, bi-directional, divergent selection for high and low juvenile body weight. It is one of the most well studied experimental populations in agricultural animals and has played an instrumental role in the understanding of the genetic basis of complex traits. In this paper, we summarize the findings from the more recent publications focusing on the efforts to identify the loci contributing to selection response as well as discuss the currently ongoing research. We conclude by describing some future research prospects that promise to bring new, interesting insights into the biology of complex traits in the near future and their implications for future animal improvement programs.Item Polyculture of Nile tilapia and shrimp at different stocking densities(Brazilian Journal of Animal Science, 2012-07) Bessa Junior, Ambrosio Paula; Azevedo, Celicina Maria da Silveira Borges; Pontes, Frederico Silva Thé; Henry-Silva, Gustavo GonzagaThis study aimed to evaluate the productivity, growth performance and economic feasibility of polyculture of Nile tilapia Oreochromis niloticus and shrimp Litopenaeus vannamei at different stocking densities. Feed was provided based on fish requirements. The experiment was conducted at the Aquaculture facility of the Universidade Federal Rural do SemiÁrido – UFERSA, in a completely randomized design with five treatments and four replicates each. Treatments consisted of a tilapia monoculture with 2 tilapias.m-2; and polyculture with 2 tilapias.m-2 and L. vannamei at four different densities (3, 6, 9 and 12 shrimps.m-2). The initial individual biomass for fish and shrimp were 1.23±0.12 g and 0.133±0.009 g, respectively. Water quality parameters, temperature, dissolved oxygen, pH and transparency were monitored. The experiment lasted 120 days and biomass gain was evaluated every two weeks. Final biomass, survival and feed conversion rates were calculated at the end of the experiment. The economic analysis showed that polyculture systems at stocking densities of nine and twelve shrimps.m-2 resulted in higher gross revenue and operational profits of 120.9% and 97.5% respectively, with mean gross return significantly higher than the monoculture. The O. niloticus and L. vannamei polyculture in oligohaline water was shown to be technically and economically feasible. These two species can be cultured together, without competing for the same resources, because they have different trophic niche, thus increasing productivity and economic returns for the farmers.