Made available in DSpace on 2016-04-28T20:15:31Z (GMT). No. of bitstreams: 1 2008 - Simone Quinelato final.pdf: 1288089 bytes, checksum: 806c125a6ebd7474f17e8efb57adbc3f (MD5) Previous issue date: 2008-02-29 / The knowledge of biology and epidemiology of cyathostomin free living stages have been helping the development of control programs that limitis anthelmintic use. However little is known about environmental larvae dynamics, mainly in tropical climate. Studies about pasture contamination can help to estimate parasitic risks for animals and to set up integrate control programs. The present study was elaborated in three complemented parts: first, it was evaluated the distribution, recovery and survival of cyatostomin infective larvae of equines in feces and pasture during 15 months. Fecal samples were monthly placed on Tifton 85 (Cynodon spp. cv. Tifton 85) pasture, from september of 2003 to september of 2004. Grass and feces were collected weekly, at 8 a.m., 1 and 5 p.m. and processed by Baermann technique. The results indicate that the environmental conditions were favorable for L3 development and survival. In feces, more L3 was recovered during the rainy period and on the grass in dry period. L3 survival was higher in the dry period for feces and grass samples. L3 were recovered during the three times of collection and no significant difference was observed among three times. The second part was more wide-ranging and approaches the distribution, recovery and survival of cyathostomin infective larvae in feces and pasture for february 2005 to march 2007. Seven days after the deposit, sample of feces and grass were collected weekly at 8 a.m., 1 p.m. and 5p.m., from three different field sites. Grass sample was divided into base (0-20 cm) and apex (20-40 cm). The samples were processed by the Baermann technique for L3 recovery. In the rainy period, more infective larvae were recovered on the feces and grass apex. In the dry period, the recovery was higher only on the grass base, as well as the L3 survival on feces and grass. More larvae were recovered at 8 a.m., except from the grass apex, where the highest recovery was at 1 p.m. The third part refers to the seasonal distribution and recovery of cyathostomin infective larvae in feces, pasture and soil. In the beginning of the seasons feces samples were placed on experimental Tifton 85 plot. The collections began one week after deposit, and later every 15 days. L3 recovered were higher in the autumn and winter and smaller in the spring and mainly in the summer. More L3 were recovered in the morning, although no statistic difference has been observed between the collection times in each season. The soil didn't demonstrate to be potential L3 reservoir, seen the low larvae recovery in this study. / O conhecimento da biologia e epidemiologia das fases pr?-paras?ticas de ciatostom?neos de eq?inos t?m contribu?do para o desenvolvimento de programas de controle que limitem a utiliza??o de anti-helm?nticos. No entanto, pouco se conhece sobre a din?mica das larvas no ambiente, principalmente nas regi?es de clima tropical. Estudos sobre o grau de contamina??o das pastagens por larvas infectantes de ciatostom?neos podem auxiliar na determina??o do risco de infec??o dos animais e fornecer dados para o estabelecimento de programas de controle integrado. O presente estudo foi dividido em tr?s etapas complementares: na primeira etapa, avaliou-se a distribui??o, recupera??o e sobreviv?ncia de larvas infectantes (L3) de ciatostom?neos de eq?inos nas fezes e na pastagem no per?odo de 15 meses. Massas fecais foram depositadas mensalmente na gram?nea Tifton 85 (Cynodon spp. cv. Tifton 85) no per?odo de setembro de 2003 a setembro de 2004. Gram?nea e fezes foram coletadas a cada sete dias, ?s 8, 12 e 17h e processadas pela t?cnica de Baermann. De acordo com os resultados, as condi??es ambientais foram favor?veis para o desenvolvimento e sobreviv?ncia das L3. Nas fezes, a recupera??o das L3 foi superior durante o per?odo chuvoso e na gram?nea no per?odo seco. A sobreviv?ncia das larvas foi superior no per?odo seco, tanto para as amostras de fezes quanto para as de gram?nea. As L3 foram recuperadas durante os tr?s hor?rios de coleta e n?o se observou diferen?a significativa entre os hor?rios. A segunda etapa foi mais abrangente e aborda o estudo da distribui??o, recupera??o e sobreviv?ncia de larvas infectantes de ciatostom?neos de eq?inos nas fezes e na pastagem no per?odo de fevereiro de 2005 a mar?o de 2007. Sete dias ap?s cada dep?sito de massa fecal foram realizadas coletas de amostras de fezes e gram?nea ?s 8, 13 e 17 h, de tr?s pontos distintos em sentido hor?rio. As amostras de gram?nea coletadas foram divididas em base (0-20 cm) e ?pice (20-40 cm), tendo sido processadas pela t?cnica de Baermann para recupera??o das L3. No per?odo chuvoso, as larvas infectantes foram recuperadas em maior n?mero das fezes e do ?pice da gram?nea. No per?odo seco, a recupera??o foi superior na base da gram?nea, assim como a sobreviv?ncia das L3 nas fezes e na gram?nea. Maior n?mero de larvas foi recuperado ?s 8 h, exceto na base da gram?nea, onde a maior recupera??o de L3 ocorreu ?s 13 h. A terceira parte refere-se ? distribui??o sazonal e recupera??o de larvas infectantes de ciatostom?neos nas fezes, na pastagem e no solo. Ao in?cio de cada esta??o do ano foram depositadas amostras de fezes no canteiro experimental de Tifton 85. As coletas iniciaram-se uma semana ap?s o dep?sito e posteriormente a cada 15 dias. As L3 foram recuperadas em maior quantidade no outono e inverno e em menor quantidade na primavera e principalmente no ver?o. No hor?rio da manh? as larvas foram recuperadas em maior n?mero, embora n?o tenha sido observada diferen?a estat?stica entre os hor?rios de coleta em cada esta??o do ano. O solo n?o demonstrou ser potencial reservat?rio de L3, visto a baixa recupera??o de larvas neste estudo.