Relação entre a imunidade passiva e a ocorrência de diarreia neonatal e doença respiratória em vitelos neonatos
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2021
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A ingestão de um colostro de boa qualidade desempenha um papel fundamental em assegurar o sucesso da transferência imunitária passiva em vitelos neonatos, sendo que, a qualidade do colostro será definida pelo seu teor de imunoglobulinas e outros compostos.
O presente estudo teve como objetivo determinar o estado imunitário em vitelas de aptidão leiteira após a ingestão de dois tipos de colostro: um de qualidade controlada (concentração de IgG do colostro conhecida na altura da alimentação) fornecido ao grupo I, e outro de qualidade não controlada (concentração de IgG do colostro desconhecida na altura da alimentação) fornecido ao grupo II. O estado imunitário foi determinado através da análise sérica de brix com recurso a um refratómetro digital e atribuída a classificação de falha ou sucesso na transferência imunitária de acordo com os valores medidos. Posteriormente, relacionou-se a classificação imunitária com a ocorrência e severidade da diarreia neonatal ou da doença respiratória.
Foi realizada a monitorização da saúde dos 2 grupos de vitelas ao longo das primeiras 4 semanas de vida, avaliando os seguintes parâmetros: temperatura rectal, estado de hidratação, globo ocular, auscultação pulmonar, classificação respiratória, descarga nasal e consistência fecal. Verificou-se que no grupo I, 74% da amostra apresentou sucesso enquanto os restantes 27% obteve falha, já no grupo II, 100% da amostra apresentou falha na transferência imunitária. A ocorrência de alterações clínicas foi significativamente diferente (p<0.05) entre os grupos, com uma maior probabilidade de desenvolver menos alterações clínicas no grupo I.
Apesar de não ter sido estabelecida a relação entre o estado imunitário e as alterações clínicas detetadas em todas as semanas do estudo, os dados da terceira semana indicam que a relação entre as variáveis foi significante (p<0.05) nesta semana. Foi ainda possível observar que em casos de falha ocorrem mais alterações clínicas, indicando um maior grau de severidade da doença. Ainda, na primeira semana do estudo foi determinada uma relação significante (p<0.05) no grupo I entre as variáveis qualidade do colostro e a severidade da doença. A prevalência de falha detetada neste estudo foi superior no grupo II enquanto a prevalência de sucesso foi superior no grupo I.
The ingestion of a good quality colostrum plays a key role in ensuring a successful transfer of passive immunity in neonatal calves, the quality of the colostrum will be defined by its content of immunoglobulins and other components. The present study aimed to determine the immune status of female calves after the ingestion of two types of colostrum: one of controlled quality (IgG concentration of colostrum know at the time of feeding) and one of uncontrolled quality (IgG concentration of colostrum unknown at the time of feeding). Immune status was determined by serum brix analysis using a digital refractometer, failure or success in the immune transfer of passive immunity was assigned according to the measured values. Subsquently, failure in the immune transfer was related to the incidence and severity of the neonatal diarrhea or the respiratory disease when it was present. A health follow-up of the two groups of calves was performed throughout the first four weeks of life, assessing the following parameters: rectal temperature, hydration status, eyeball, lung auscultation, respiratory classification, nasal discharge and fecal consistency. It was found that in group I, 74% of the sample obtained success while the remaining 27% of the sample obtained failure, while in group II, 100% of the sample was obtained failure in the transfer of immunity. The occurrence of clinical changes was significantly different (p < 0,05) between the groups that each calf belongs, with a higher probability of developing fewer clinical alterations in group I. Although the relationship between the immune status and the clinical changes detected was not established in all four weeks of the study, the data from the third week indicate that the relationship between the variables was significant (p < 0,05) in this week. It was also possible to observe that in failure cases more clinical changes occur, indicating a higher degree of the severity of the disease. through the data obtained that in case of FIPT classification, more clinical changes occur, suggesting a higher degree of severity of the disease associated with this classification. Also, in the first week of the study, a significant relationship (p<0.05) was determined in group I between the variables colostrum quality and disease severity. The prevalence of failure detected in this study was higher in group II while the prevalence of success was higher in group I.
The ingestion of a good quality colostrum plays a key role in ensuring a successful transfer of passive immunity in neonatal calves, the quality of the colostrum will be defined by its content of immunoglobulins and other components. The present study aimed to determine the immune status of female calves after the ingestion of two types of colostrum: one of controlled quality (IgG concentration of colostrum know at the time of feeding) and one of uncontrolled quality (IgG concentration of colostrum unknown at the time of feeding). Immune status was determined by serum brix analysis using a digital refractometer, failure or success in the immune transfer of passive immunity was assigned according to the measured values. Subsquently, failure in the immune transfer was related to the incidence and severity of the neonatal diarrhea or the respiratory disease when it was present. A health follow-up of the two groups of calves was performed throughout the first four weeks of life, assessing the following parameters: rectal temperature, hydration status, eyeball, lung auscultation, respiratory classification, nasal discharge and fecal consistency. It was found that in group I, 74% of the sample obtained success while the remaining 27% of the sample obtained failure, while in group II, 100% of the sample was obtained failure in the transfer of immunity. The occurrence of clinical changes was significantly different (p < 0,05) between the groups that each calf belongs, with a higher probability of developing fewer clinical alterations in group I. Although the relationship between the immune status and the clinical changes detected was not established in all four weeks of the study, the data from the third week indicate that the relationship between the variables was significant (p < 0,05) in this week. It was also possible to observe that in failure cases more clinical changes occur, indicating a higher degree of the severity of the disease. through the data obtained that in case of FIPT classification, more clinical changes occur, suggesting a higher degree of severity of the disease associated with this classification. Also, in the first week of the study, a significant relationship (p<0.05) was determined in group I between the variables colostrum quality and disease severity. The prevalence of failure detected in this study was higher in group II while the prevalence of success was higher in group I.
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Orientação: João Cannas da Silva
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MESTRADO INTEGRADO EM MEDICINA VETERINÁRIA, MEDICINA VETERINÁRIA, VETERINÁRIA, BOVÍDEOS, SISTEMA IMUNITÁRIO, DOENÇAS, VETERINARY MEDICINE, BOVIDS, IMMUNE SYSTEM, DISEASES, COLOSTRUM, COLOSTRO