Foram estudados os efeitos da alimentação com pastagem cultivada de aveia + azevém + trevo vesiculoso ou silagem de milho + concentrado sobre o desempenho e os aspectos quantitativos da produção de lã de ovelhas de cria de parto simples ou duplo da raça Ideal, bem como o efeito destes regimes alimentares sobre o ganho de peso, as características de carcaça e os componentes do peso vivo de cordeiros alimentados ao pé da mãe. Para as variáveis estudadas das ovelhas, apenas o rendimento de lã diferiu significativamente (P<0,01) entre os sistemas alimentares, sendo superior para aquelas alimentadas com silagem de milho + concentrado. Quanto ao tipo de parto, não houve diferenças significativas (P>0,05) para nenhuma das variáveis estudadas. Para os cordeiros, os valores obtidos de desempenho, características da carcaça e componentes do peso vivo, não diferiram significativamente (P>0,05) entre tratamentos.
Fish reproduction in floodplain rivers is often linked to flow regime and with the inundation of floodplain habitats. However, in confined rivers, where floodplains are absent, the relation between reproduction and flow can in comparison be expected to be distinct. In this study, we describe the reproductive life-history of Hemiancistrus fuliginosus and Hypostomus isbrueckeri in a confined river and discuss its differences relative to floodplain loricariids and also the implications for effects of dam construction and flow regulation. We found the reproductive peak of both species occurred during lowering waters, just after maximum river flow, in contrast to floodplain species that tend to spawn during rising waters. The studied species presented attributes of equilibrium life-history strategy, which are related to predictable river flow variation. Because both species spawned during low river flow, which is historically predictable in summer, we suggest that their reproduction may be severely disrupted, depending on how flow regime is affected by dam operation. These results have implications for assessing and mitigating the impacts of river damming on fish populations in confined rivers, and we point to ecologically driven flow management and conservation of free-flowing rivers as mitigation and conservation alternatives.
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