Mestrado em Zootecnia (EVZ)
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Navegando Mestrado em Zootecnia (EVZ) por Por Orientador "Couto, Victor Rezende Moreira"
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Item Nitrato encapsulado na suplementação para novilhos de corte em pastejo(Universidade Federal de Goiás, 2020-10-02) Berti, Guilherme Felipe; Silva, Maurícia Brandão da; http://lattes.cnpq.br/9608210292530980; Fernandes, Juliano José Resende; http://lattes.cnpq.br/7949776443064259; Couto, Victor Rezende Moreira; http://lattes.cnpq.br/4329309889502866; Couto, Victor Rezende Moreira; Barbosa, Analívia Martins; Araújo, Rafael Canonenco deThe present work evaluated the effects of the partial replacement of soybean meal with encapsulated nitrate in suplemented grazing beef cattle diets. The experimental design was a cross-over, conducted in two consecutive periods of 21 days each. Eight crossbred steers (average body of 345 kg), castrated, fitted with ruminal cannula were distributed in two treatments: Control - multiple supplement based on soybean meal, without nitrate; and NE - supplement with encapsulated nitrate (5% on the concentrate dry matter), replacing soybean meal. Each animal were daily supplemented with 1.0% of his body weight. The data were analyzed using mixed models, using the MIXED procedure of the SAS program and comparisons between treatments were made using the F test, at the level of 5% probability. The total dry matter intake (DMI) was not affected (P = 0.459), as well as the forage DMI (P = 0.906). However, a decreae of the concentrate DMI rate (% body weight) was observed (from 0.92% to 0.88%) (P = 0.024). Control and EN animals showed higher concentrate intake during three hours after feed, however EN had lower and slower consumption throughout the day. The use of EN did not change the digestibility of the dry matter (P = 0.090), as well as the digestibility of the crude protein (P = 0.160), neutral detergent fiber (P = 0.122) and non-fibrous carbohydrate (P = 0.872), but decreased the ether extract digestibility from 68.81% to 61.21% (P <0.05). The EN decreased butyrate (P <0.01) and valerate rates (P <0.0095) 9 hours after feeding. There was no effect of EN on propionate (P> 0.1215) and total AGCC rates (P> 0.8620), whereas EN increased the total acetate rates 3, 6 and 12 hours after supplementation (P <0.0018). There was no effect of EN on the ruminal NH3 concentration (P> 0.5845). In summary, EN provides lower palatability to concentrate diets, maybe increasing the time spent in the trough throughout a day, but did not decreases the dry matter intake of suplemented grazing cattles.Item Probiótico na terminação de bovinos em pastejo durante o período da seca(Universidade Federal de Goiás, 2019-02-26) Calaça, Alana Maria Menezes Di; Fernandes, Juliano José de Resende; http://lattes.cnpq.br/7949776443064259; Couto, Victor Rezende Moreira; http://lattes.cnpq.br/4329309889502866; Couto, Victor Rezende Moreira; Santos, Mateus Castilho; Restle, JoãoProbiotics have been promised to be an alternative additive to antibiotic use and as a growth promoter. However, the performance results of animals fed probiotics are variable. The objectives were to evaluate the productive performance of Nellore bulls on grazing system for intensive fattening during the dry season, receiving probiotic concentrate composed of Bacillus toyonensis; influence of probiotic on ruminal and intestinal mucosa development and probiotic effect on digestibility and ruminal fermentation. The experiment was carried out between July and November 2017, which corresponds to the dry period in the region. Four animals were slaughtered at the beginning of the experiment so that the initial carcass yield could be estimated. Nellore bulls (n = 80) with initial mean weight of 354.02 ± 3.38 kg were blocked according to body weight and divided into two treatments: concentrate with probiotic and concentrate without probiotic (control). They were allocated in 16 paddocks formed by Urochloa brizantha, supplemented at 2% of the body weight in concentrate. At the end of 133 days of experiment, the animals were slaughtered and data of carcass weight, yield, carcass gain, average daily carcass gain and 12th-rib fat thickness were obtained. The in vivo digestibility assay was performed with eight rumen cannulated steers, in a cross over 2x2 design, with two treatments and two periods. Titanium dioxide was used as an external marker to estimate fecal excretion and iFDN was used as an internal marker to estimate dry matter intake. On the last day of each experimental period, ruminal fluid was collected to evaluate the concentration of short chain fatty acids and ammoniacal nitrogen. The use of probiotic composed of Bacillus toyonensis did not improve final body weight (528.2 ± 3.38 kg – p=0,2360) nor the daily average gain (1,333 kg– p= 0,2531) and feed efficiency (0.165– p=0,2016). The subcutaneous fat thickness was lower in animals receiving the probiotic (4.06 vs. 2.97 mm mm – p=0,0423). There was no influence of probiotic on other carcass traits. No significant effect on the development of the ruminal and intestinal epithelium was observed with the use of probiotic. Bacillus toyonensis did not improve dry matter intake and nutrient digestibility. There was no effect on rumen fermentation. Probiotic based on Bacillus toyonensis altered fat deposition in carcasses.