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Medicina da produção leiteira : estudos de relação entre o desempenho reprodutivo e as mastites
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Orientador(es)
Resumo(s)
O impacto das mastites na eficiência reprodutiva dos bovinos leiteiros, tem sido estudado ao longo dos últimos anos, por diversos autores. O objetivo do presente estudo, foi analisar a possível associação causal entre a ocorrência de mastites subclínicas e a alteração do desempenho reprodutivo.
Recorrendo a uma base de dados de contraste leiteiro, na qual existiam registos provenientes de 9 explorações nacionais, introduzidos entre 1996 e 2016, procedeu-se à análise da relação da contagem de células somáticas, com o intervalo parto-conceção. Os resultados obtidos demonstraram que, à medida que aumenta a contagem de células somáticas, aumenta o intervalo parto-conceção. Tais resultados foram estatisticamente significativos e mais pronunciados para os dados relativos à segunda lactação. Observou-se ainda que, para cada aumento do número de eventos, cuja contagem de células somáticas se encontra acima do limiar de distinção entre infetado e saudável, o intervalo parto-conceção aumenta 28,7 dias para a primeira lactação e 27,9 dias para a segunda. Tais resultados, sugerem a hipótese de haver uma relação da cronicidade da infeção, com a fertilidade.
Assim, à semelhança do reportado por autores anteriores, os resultados obtidos apontam a existência de uma relação entre as mastites subclínicas e o desempenho reprodutivo dos bovinos leiteiros.
ABSTRACT - Dairy Production Medicine: studies of the relationship between reproductive performance and mastitis - The impact of mastitis on reproductive performance of dairy cattle has been studied throughout the last years, by several authors. The objective of this study was to evaluate the possible causal association between the occurrence of subclinical mastitis and altered reproductive performance. Through the analysis of a database, in which there was access to milk recording data from 9 national dairy farms, introduced from 1996 to 2016, the relationship between the somatic cell count and the calving-to-conception interval was analyzed. The obtained results showed that, as the somatic cell count increases, the calving-to-conception interval increases. These results were statistically significant and more pronounced on the second lactation. Furthermore, it was observed that, with increases in the number of mastitis episodes, in which somatic cell counts were above the considered threshold between infected and healthy, the calving-to-conception interval progressively increased 28,7 days for the first lactation and 27,9 days for the second. These results support the existence of a relationship between the chronicity of the episodes and fertility. As such, similarly to results presented by previous authors, this study supports the existence of a direct relationship between mastitis and the reproductive performance of dairy cattle.
ABSTRACT - Dairy Production Medicine: studies of the relationship between reproductive performance and mastitis - The impact of mastitis on reproductive performance of dairy cattle has been studied throughout the last years, by several authors. The objective of this study was to evaluate the possible causal association between the occurrence of subclinical mastitis and altered reproductive performance. Through the analysis of a database, in which there was access to milk recording data from 9 national dairy farms, introduced from 1996 to 2016, the relationship between the somatic cell count and the calving-to-conception interval was analyzed. The obtained results showed that, as the somatic cell count increases, the calving-to-conception interval increases. These results were statistically significant and more pronounced on the second lactation. Furthermore, it was observed that, with increases in the number of mastitis episodes, in which somatic cell counts were above the considered threshold between infected and healthy, the calving-to-conception interval progressively increased 28,7 days for the first lactation and 27,9 days for the second. These results support the existence of a relationship between the chronicity of the episodes and fertility. As such, similarly to results presented by previous authors, this study supports the existence of a direct relationship between mastitis and the reproductive performance of dairy cattle.
Descrição
Dissertação de Mestrado Integrado em Medicina Veterinária
Palavras-chave
bovinos leiteiros contagem de células somáticas intervalo parto-conceção mastites desempenho reprodutivo calving-to-conception interval dairy cattle mastitis reproductive performance somatic cell count
Contexto Educativo
Citação
Fraga, C.A.M.C. (2018). Medicina da produção leiteira : estudos de relação entre o desempenho reprodutivo e as mastites. Dissertação de mestrado. Universidade de Lisboa, Faculdade de Medicina Veterinária, Lisboa.
Editora
Universidade de Lisboa, Faculdade de Medicina Veterinária