Orientador: Ricardo Velludo Gomes de Soutello Soutello / Resumo: Os parasitos influenciam de maneira significativa a bovinocultura no Brasil, sendo a aplicação de endectocidas da família das lactonas macrocíclicas umas das formas mais utilizadas para o controle, porém podem proporcionar contaminação ao ambiente, visto que sua eliminação é principalmente via fezes e urina. Com isto, este trabalho objetivou verificar o desenvolvimento de microrganismos edáficos e a decomposição das fezes de bovinos ao longo do tempo após o tratamento com diferentes lactonas macrocíclicas. Foram avaliadas as fezes de doze animais, divididos em quatro grupos homogêneos, sendo o G1- controle (sem a administração de endectocida), G2-Ivermectina 1%, G3-Ivermectina 3,15% e G4- Moxidectina 1%. As colheitas das fezes dos animais foram realizadas nos dias 0, 7, 14, 21, 28,42 e 56 pós tratamento, e submetidas a três ambientes de decomposição, sendo ambiente controlado (BOD), Natural (NAT): exposto as condições climáticas naturais e enterradas no solo (Solo). Nos dias das cada colheitas e 112 dias após cada colheita, foi realizada a avaliação matéria orgânica. As avaliações da microbiota das fezes foram realizadas nos dias das colheitas e 7 após cada colheita. Observou-se que as ivermectinas em suas duas concentrações (1 e 3,15%) interferiram no desenvolvimento da população microbiana, já a moxidectina 1% não alterou a dinâmica populacional das bactérias, que também não foi influenciada pelo ambiente exposto em nenhum dos tratamento. A decomposição não foi afetada pela... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

This book was assembled using the latest information for compiling the nutrient requirements of sheep, goats, cattle and water buffalo. Because of the complexity of the interactions between an animal, its diet, its physiological state, and the environment; the values depicting the nutrient requirements are estimates and not absolutes. These values, however, are considered to be adequate to meet the minimum requirements of healthy animals maintained in a thermoneutral environment. The mean energy and protein values used in the nutrient tables were arrived at from combining values found in the literature and those provided in personal communication with animal nutritionists in many developing countries. In some cases, only two or three observations were found for estimating the values used. Future research in ruminant nutrition should be designed to provide information needed to confirm or modify the values presented here. Feed composition tables representing feeds commonly found in Latin America, Africa, Asia and the Middle East have been included for an easy reference when formulating diets. Units of expression of data in the tables of feed composition and animal nutrient requirements are presented using three systems: Metabolizable energy (ME), net energy (NE); total digestible nutrients (TDN) and Scandinavian feed units (FU). conversion factors from SE to ME, TDN, etc., are presented in Section 1 for those who need this information. Also a list of abbreviations used appear in Appendix 5. A brief discussion showing three methods of calculating rations by hand are presented. Each of these methods permits some consideration for calculating a "least-cost" ration. It is important, however, that the person formulating a diet has a knowledge of the animal's nutrient requirements, an understanding of the digestibility and utilization of feeds and the various combinations required to formulate a diet adequate to supply all the needs of animals. Examples of hand calculated rations appear in Appendix 3. Adulteration of feedstuffs is a common complaint from livestock producers in many developing countries. This problem has been encountered at various times throughout most regions of the world. In section 12, some suggestions are offered as a means to establish quality control regulations and to set standards for all manufactured feedstuffs offered for sale.

Managing cattle to disseminate seeds of desirable plants, or alternatively, to restrict weed seed contamination on rangelands is of interest to managers. Four experiments were conducted to determine effects of ruminant digestion on germination of ingested seeds. A number of plant species representing a variety of seed size and seed coat hardness were subjected to in vitro digestion. Experiment one was conducted to determine effect of varying lengths of digestion time on seed germination. Seed germination varied by plant species in response to length of digestion. Germination of large soft-coated seeds, such as bluebunch wheatgrass (Agropyron spicatum (Pursh) Scribn. & Smith Goldar) and basin wildrye (Elymus cinereus Scribn & Merril Magnar), was reduced to 0%. Smaller grass seeds, such as Sherman big bluegrass (Poa secunda Presl. Sherman), survived but germination declined following 24-hour, 48-hour, and 72-hour digestion. Experiment two examined effect of different stages of ruminant digestion on seed germination. The combination of Stage I (rumen-simulated digestion) and Stage II (abomasal-simulated digestion) resulted in greatest seed mortality. Two water treatments were included to evaluate the effects of high temperatures (39��C), moisture uptake, and lack of oxygen. Water + O��� and Water + CO��� reduced germination, however not as much as Stage I and Stage II treatments. The third experiment determined effects of diet quality on seed germination. Seeds digested in rumen fluid collected from steers fed a 72% corn concentrate diet resulted in 0% germination for all species. Grass seed germination was low for seeds digested in rumen fluid collected from steers fed a forage diet. Whitetop (Cardaria draba (L.) Hand.) germination was 24% and 28% for 35-hour and 59-hour roughage treatment, respectively, and germination was 0% for 35-hour and 59-hour concentrate treatments. Germination of water-only treatments for most species was reduced in comparison to the control treatment, but was greater than remaining treatments. Experiment four evaluated germination of seeds exposed to in situ versus in vitro digestion. In situ digestion resulted in lower seed germination than in vitro digestion for all species examined. Large, soft grass seeds may not be suitable candidates for reseeding rangelands. However, it is important for managers to recognize that cattle may distribute viable weed seeds in feces. Confining cattle or supplementing with high concentrate diets may help prevent spread of weedy species. / Graduation date: 1997

Reproduction de : Thèse de doctorat : Sciences animales : Toulouse, INPT : 2006. / Titre provenant de l'écran-titre. Bibliogr. 295 réf.

Thèse de doctorat : Sciences animales : INPL : 2007. / Titre provenant de l'écran-titre. Bibliogr.

No description available.

No description available.

No description available.

No description available.

A study on the epidemiological dynamics of gastrointestinal nematodes of small ruminants was conducted in a semi-arid area of Kenya over a period of two years. Three major trichostrongylid species were identified; Haemonchus, Trichostrongylus and Oesophagostomum. Trichuris and Strongyloides species were occasionally encountered. Of the major trichostrongylids, Haemonchus spp. was the most prevalent (90%) and accounted for about 80% of the total worm burden. This species was found to undergo hypobiosis at levels that varied with seasons: nil levels of hypobiosis were recorded during the wet months and as much as 80% was recorded during the dry months. Hypobiosis was not investigated in the other nematode species. Evaluation of the relationship between the faecal egg count and the worm burden showed that the two parameters were more highly correlated during the wet months than during the dry months. This was a desirable situation because it is during the wet season that livestock owners in this area need to closely monitor the worm burdens in their animals. Treatment with ivermectin before the onset of the rains not only delayed the onset of egg shedding but also controlled clinical helminthiasis. In addition, a temporal change in the pattern of the appearance of infective larvae on pasture was observed; the appearance was delayed for about a month after the onset of the rains. The effect of treatment administered during the rains was a temporary and a short-lived relief of infection as evidenced by a brief decline in egg output: it had no detectable impact on pasture infectivity. These results suggested that removal of hypobiotic larvae before they resumed development had the combined benefit of reducing both the severity of clinical helminthiasis and the level of pasture contamination. This impact was expressed in improved flock performance and particularly in the improvement of birth weights that subsequently enhanced kid and lamb survival rates. Probably due to