Made available in DSpace on 2014-12-17T15:34:43Z (GMT). No. of bitstreams: 1 JoaoVEN_DISSERT.pdf: 2633777 bytes, checksum: a59b41665f97067cdafb895c7d67745c (MD5) Previous issue date: 2012-02-16 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / He aim of this study was to evaluate the structural characters, herbage accumulation, nutritive value and performance of sheep in different tropical pastures. The treatments were two cultivars and two of the genera Panicum Brachiaria pastures under intermittent stocking and variable stocking rate, in the rainy season. We evaluated the masses and the components of herbage pre grazing in two layers, and after grazing. Chemical analyzes were made of the stems and leaf blades pre grazing in two layers. We used 48 male sheep and whole for the assessment of individual weight gain and area, and anestrous females to adjust the stocking rate. In the cv. Massai showed the highest herbage mass, leaf blades and dead material, and the largest volume density and leaf blade: stem pre grazing. There was no difference among cultivars for the percentage of leaf blade (PLB) in both strata, but the higher the PLB was higher than the bottom. The highest percentage of dead material (PDM) was observed in cvs. Massai and Marandu in the two strata. In cvs. Massai and Piat? were observed lower levels of crude protein in stem and leaf. In stratum 0-25 cm lower nutritional value was observed in the stem in the leaf blades did not grant the nutritional value among the strata. Herbage mass, leaf blade, PLB and proportion of stem in the residue of the Massai pastures were higher than cv. Aruana. There was no difference for efficiencies in harvest leaf and stem between the cultivars. The cv. Massai got the higher accumulation of leaf per cycle per day. Animals kept in grass swards Aruana had the highest average daily gain. The higher stocking rates and earnings per area were observed in grass swards and Marandu Massai. The cultivars are suitable for sheep meat production in the rainy season / O objetivo deste estudo foi avaliar os caracteres estruturais, o ac?mulo de forragem, o valor nutritivo e o desempenho de ovinos em diferentes pastagens tropicais. Os tratamentos constitu?ram em duas cultivares dos g?neros Panicum e duas de Brachiaria, manejadas sob lota??o intermitente e taxa de lota??o vari?vel, na ?poca das ?guas. Foram avaliadas as massas e os componentes da forragem no pr? pastejo em dois estratos, e no p?s pastejo. Foram feitas an?lises bromatol?gicas dos colmos e das l?minas foliares no pr? pastejo em dois estratos. Utilizou-se 48 ovinos machos e inteiros para a avalia??o do ganho de peso individual e por ?rea, al?m de f?meas em anestro para ajuste na taxa de lota??o. Na cv. Massai foram observadas as maiores massa de forragem, de l?minas foliares e de material morto, al?m da maior densidade volum?trica e rela??o l?mina foliar:colmo no pr? pastejo. N?o houve diferen?a entre as cultivares para o percentual de l?minas foliares (PLF) em ambos os estratos, por?m o PLF no superior foi maior que no inferior. O maior percentual de material morto (PMM) foi observado nas cvs. Massai e Marandu nos dois estratos. Nas cvs. Massai e Piat? foram observados os menores teores de prote?na bruta no colmo e na l?mina foliar. No estrato de 0 25 cm foi observado menor valor nutritivo no colmo, nas l?minas foliares o valor nutritivo n?o deferiu entre os estratos. A massa de forragem, de l?mina foliar, PLF e propor??o de colmo no res?duo dos pastos de Massai foram superiores aos da cv. Aruana. N?o houve diferen?a para as efici?ncias na colheita de l?mina foliar e colmo entre as cultivares estudadas. A cv. Massai obteve os maiores ac?mulos de l?mina foliar por ciclo e por dia. Os animais mantidos em pastos de capim Aruana obtiveram os maiores ganhos m?dios di?rios. As maiores taxas de lota??o e ganhos por ?rea foram observadas nos pastos de capim Massai e Marandu. As cultivares testadas s?o adequadas a produ??o de carne ovina na ?poca das ?guas