Terminação de novilhos Nelore suplementados em pastagens : comportamento, desempenho, características da carcaça e da carne e a economicidade do sistema

• Autor(a) principal: Silva, Robério Rodrigues
• Data de Publicação: 2008
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/1833
• topic: Novilhos Nelore; Suplementação a pasto; Ácido linoléico conjugado; Comportamento ingestivo; Aspectos econômicos; Etologia; Qualidade de carne; Ruminação; Brasil.; Nellore; Pasture supplementation; Conjugated linoleic acid; Feeding behavior; Economic aspects; Ethology; Meat quality; Rumination; Brazil.; Ciências Agrárias; Zootecnia

This work was carried-out to study the effect of the supplementation levels on the intake behavior, animal performance, physical characteristics of the carcass, the chemical composition of the Longissimus muscle and economic evaluation steers finished in pasture. The field experiment was developed by the Southwestern State University of Bahia. It?s was used 40 Nellore steers of 373.7 + 14.9 kg initial weight and 26 months of age in four treatments T00 = mineral Salt; T03 = 0.3% of energy and protein supplementation; T06 = 0.6% of energy and protein supplementation and T09 = 0.9% of energy and protein supplementation. The animals were kept in this handling during 84 days being 14 of them destined to adaptation. The animals had been observed visually by two periods of 12 hours of the six to the 18 hours. The times of grazing (P<0.00001), ruminating (P<0.06) and idle (P<0.00006) had suffered to quadratic effect and the time from manger increasing linear effect (P<0.00001). The intake of total dry substance in kg for animal per day and percentage of the live weight had not been affected by the supplement levels (P>0.15). The intake of deriving total dry substance of the pasture and the entire variable related to the fiber in neutral detergent and fiber in acid detergent had decreased linearly (P<0.0002). The time of total chew, ruminated cake number and the time for ruminating of each cake had presented cubical effect (P<0.0001). The number of chews for cake decreased linearly (P<0.000001). The number of periods of grazing (P<0.15) and time for period of manger (P<0.000001) had increased linearly. The time for period of grazing decreased linearly (P<0.000001). The number of periods of ruminating (P<0.02), number of periods of idle (P<0.000001) and time for period of ruminating (P<0.0002) had suffered quadratic effect. The number of periods of manger suffered cubical effect (P<0.000001). The time of duration of periods of idle was not modified (P>0.15). The supplement not only compromises the variable diurnal to on the intake behavior in function of the amount of food more also ingested for its composition and pasture:concentrate reason, lacking of attention in the balancing of rations. It was estimated the impacts of the administration of oxide during periods of 28, 56 and 84 days. Gains in weight differ (P <0.01) at all levels of supplementation during periods of 28 and 56 days. In 84 days was no difference (P <0.01) xxii only for the levels of 0.6 and 0.9%. The conversion food and feed efficiency was determined in periods of 56 and 84 days due to negative earnings in the initial period of 28 days. In both periods there was evaluated effect (P <0.01) with elevation of the food conversion efficiency and decrease food. It follows that to ensure the accuracy of the experimental results is not necessary to include the data of weight gain, feed conversion efficiency and the results from the sampling units used to determine the consumption in pasture and which was given the chromium oxide. The supplementation was decreasing effect on pasture intake and in a neutral detergent fiber. There was linear effect in terms of increasing levels of supplementation to crude protein intake, ether extract, not fibrous carbohydrates, total nutrients digestibility, digestibility energy and metabolizble energy. During the rainy season no variable was affected. The animal performance presented linear effect in the growing phase of supplementation and has remained unchanged in rainy season. The feed conversion and feed efficiency were positively affected by the inclusion of levels of supplementation. There was growing linear effect on digestibility coefficients of dry matter, crude protein and not fibrous carbohydrates. The digestibility of neutral detergent fiber presented as quadratic effect of the ether extract was not affected. During the rainy season, none of the variables was affected. By increasing the inclusion of concentrate and therefore the energy density of diet, the greater intake of nutrients promotes improvements in animal performance. However, the occurrence of negative effect associations may undermine the performance biological, and therefore the economy. It had effect on fat thickness (P<0.15), amount of fat and Longissimus muscle area of corrected for 100 kg of weight of hot carcass (P<0.02). The excessively characteristic physics of the carcass had not been affected (P>0.15). Moisture, crude protein, ashes, total fat and cholesterol total had not effect (P>0.15). They had suffered to decreasing linear effect the fat acid heptadecenoic (P<0.07), octatrienoic n-3 (P<0.08) and docosahexaenoic (P<0.11). Fat acid octadecenoic suffered increasing linear effect (P<0.05). Fat acid the vaccenic cis (P<0.06) and octadecatrienoic n-6 (P<0.08) had suffered quadratic effect. The excessively fat acid ones had not been affected (P>0.15) by the supplementation. Total concentration of fat acid omega 3 had decreased linearly (P<0.09) while the reason omega 6/ômega 3 had grown linearly (P<0.0001). The concentrations of monounsaturated fat acid, polyunsaturated fat acids, saturated fat acid and omega 6 fat acid had not been affected xxiii (P>0.15) by the supplementation. The termination of Nellore steers in pasture supplemented does not bring substantial alterations to the physical or chemical characteristics of the carcass. The intensification of production process and consequent increase in number of annual cycles caused an increase in cost of produced meat. The supplementation levels raised the amount of beef produced per hectare, increased the number of productive cycles and therefore created a differentiation at time of sale the animals which is in practice, different prices depending on month of sale lots of animals. The curve of growth of revenue is less sharp than the curve of growth of costs, directing for a flattening of profit according to level of supplementation studied. Better results obtained biological fees for high levels of supplements are not economically sustainable because of the high cost of production. Levels of supplementation in termination, less than 0.3% of body weight, have economic potential.