9 research outputs found
Recommended from our members
Effects of degree and timing of social housing on reversal learning and response to novel objects in dairy calves
Rodents and primates deprived of early social contact exhibit deficits in learning and behavioural
flexibility. They often also exhibit apparent signs of elevated anxiety, although the relationship between these effects has not been studied. To investigate whether dairy calves are similarly affected, we first compared calves housed in standard individual pens
(n = 7) to those housed in a dynamic group with access to their mothers (n = 8). All calves learned to approach the correct stimulus in a visual discrimination task. Only one individually housed calf was able to re-learn the task when the stimuli were reversed, compared to all but one calf from the group. A second experiment investigated whether this effect might be explained by anxiety in individually housed animals interfering with their learning, and tested varying degrees of social contact in addition to the complex group: pair housing beginning early (approximately 6 days old) and late (6 weeks old). Again, fewer individually reared calves learned the reversal task (2 of 10 or 20%) compared to early paired and grouped calves (16 of 21 or 76% of calves). Late paired calves had intermediate success. Individually housed calves were slower to touch novel objects, but the magnitude of the fear response did not correlate with reversal performance. We conclude that individually housed calves have learning deficits, but these deficits were not likely associated with increased
anxiety
Collection and morphological characterization of sweet potato landraces in north of Rio de Janeiro state Coleta e caracterização morfológica de variedades locais de batata-doce no norte do Rio de Janeiro
The traditional farmers play an important role in plant genetic resources conservation. Collecting the germplasm maintained by these farmers is a very important action to avoid genetic variability losses. The goals of this work were to collect sweet potato from farms in the north of Rio de Janeiro state; to gather information regarding to the farmers profile, and to characterize the sweet potato landraces collected using morphological descriptors. Fifty three farms were visited in six collection expedition and 46 accessions were collected. During the visits the farmers were interviewed using a query with ten items. Six root traits and eight descriptors for vegetative parts were used for morphological characterization. The data were analyzed based on Cole-Rodgers distance and clustering was done with UPGMA method. Familiar agriculture with subsistence objective was observed and sweet potato was cultivated by 72% of the farmers at least for more than a decade, supporting the observation that this vegetable is traditionally cultivated in small areas in the specific region. The morphological characterization was efficient to detect genetic variability among accessions, revealing that traditional farmers from Campos dos Goytacazes and São João da Barra are responsible for sweet potato genotypes conservation with expressive genetic diversity in their properties. There was no relationship between genetic distance and collecting areas.<br>Os agricultores tradicionais têm um papel fundamental na conservação dos recursos genéticos vegetais e a coleta de germoplasma mantido por esses produtores é muito importante para evitar a perda da variabilidade genética. Os objetivos deste trabalho foram coletar germoplasma de batata-doce em propriedades rurais situadas no norte do estado do Rio de Janeiro; levantar informações quanto ao perfil dos produtores rurais visitados durante as coletas, e caracterizar morfologicamente as variedades locais de batata-doce coletadas. Em seis viagens de coleta foram visitadas 53 propriedades rurais, e coletados 46 acessos. Em todas as visitas foi possível entrevistar o produtor por meio de questionário contendo dez itens. Para a caracterização, foram usados seis caracteres de raiz e oito da parte aérea. A análise dos dados foi efetuada com o uso da distância de Cole-Rodgers e o agrupamento foi gerado com o método UPGMA. Foi constatado predomínio da agricultura familiar, voltada para subsistência, sendo que 72% dos agricultores cultivavam a batata-doce há mais de uma década, o que evidencia a tradição de cultivo desta hortaliça em pequenas áreas na região. A caracterização morfológica foi eficiente para detectar a variabilidade genética entre os acessos, demonstrando que os agricultores tradicionais dos municípios de Campos dos Goytacazes e São João da Barra detêm genótipos de batata-doce com expressiva diversidade genética em suas propriedades. Não foi detectada correlação entre a distância genética e os locais de coleta