Home Itens selecionados Provedores de dados OAI Créditos Sobre Ajuda

			Busca avançada
	Provedor de dados Ciência Rural (5) Autor Franti,Charles (5) Riemann,Hans (5) Rojas,José Alfonso Barajas- (2) Barajas-Rojas,Jose Alfonso (1) Barajas-Rojas,José Alfonso (1) Rojas,José Alfonso Barajas (1) Mais... Palavra-chave ELISA (3) Infectious diseases (2) México (2) Serological screening (2) Antibodies (1) Calving intervals (1) Cattie diseases (1) Cohort (1) Markov Chain (1) Pregnancy (1) Prevalence (1) Sentinels (1) Seroconversion (1) Young (1) Mais... Tipo do documento Info:eu-repo/semantics/article (5) Ano 1993 (5) País Brazil (5) Idioma Inglês (5)		Ordenar por:  Relevância Autor Título Ano Registros recuperados: 5 Primeira ... 1 ... Última A STUDY OF ASSOCIATION BETWEEN ELISA RESPONSE TO INFECTIOUS DISEASE AGENTS AND CALVING INTERVAL IN CATTLE IN THE TROPICS OF MÉXICO Ciência Rural Barajas-Rojas,José Alfonso; Riemann,Hans; Franti,Charles. Forty eight cows of Holstein-Zebu crosses with at least one completed pregnancy were tested for antibodies to 20 disease agents. The testing was performed within one month (average two weeks) after calving when the IgG level constantly reaches its lowest value during the cows reproductive cycle. The results indicate that increasing levels of IgG against Leptospira interrogans serovar hardjo and Mycobacterium paratuberculosis may be associated with an increased calving interval. Increase in calving intervals could not be explained by age of cows or their genotypic characteristics. Tipo: Info:eu-repo/semantics/article Palavras-chave: Infectious diseases; Antibodies; Calving intervals; México. Ano: 1993 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84781993000300015 MARKOV CHAIN MODELING OF ENDEMIC CATTLE DISEASES IN THE TROPICS OF MEXICO Ciência Rural Rojas,José Alfonso Barajas; Riemann,Hans; Franti,Charles. Endemic diseases measured by prevalence of IgG antibodies by ELISA all showed remarkably stable overall prevalences over a study period of 3 years. This however does not mean that incidence is low or absent. Observed transition from the state of being positive for a disease to the state of being negative and vice versa suggested fairly high incidence rates (and rates of waning antibodies) for all 19 disease agents tested for. In spite of this dynamic situation Markov Chain simulations indicate that a steady prevalence is reached in a fairly short time. Markov Chain simulations may also be useful in elucidating seasonal changes in prevalence. Tipo: Info:eu-repo/semantics/article Palavras-chave: Prevalence; Markov Chain; México; ELISA. Ano: 1993 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84781993000300014 SEROLOGICAL SCREENING FOR INFECTIOUS CATTLE DISEASES: I. INFLUENCE OF REPRODUCTIVE STATUS Ciência Rural Barajas-Rojas,Jose Alfonso; Riemann,Hans; Franti,Charles. A cohort of 125 cows (Zebu-Holstein crosses) were screened every two months during a period of two years for IgG antibodies to 20 viral, bacterial, rickettsial and parasitic agents. The screening was performed on sera using the ELISA procedure. The IgG levels fluctuated during pregnancy in a regular and similar way for all the antigens tested. IgG reached its lowest levels in the fourth and seventh month of pregnancy, a significant increase ocurred during the last month of pregnancy and this was followed by a precipitous decline during the first month post partum. The IgG fluctuations associated with the different phases of reproductive status may interact with seasonal changes in IgG levels. The changes in IgG levels during pregnancy may have the result... Tipo: Info:eu-repo/semantics/article Palavras-chave: Cohort; Serological screening; Pregnancy. Ano: 1993 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84781993000100013 SEROLOGICAL SCREENING FOR INFECTIOUS CATTLE DISEASES: II. ASSOCIATION BETWEEN PREVALENCE AND LEVEL OF ELISA RESPONSE Ciência Rural Rojas,José Alfonso Barajas-; Riemann,Hans; Franti,Charles. A herd of cattle (Holstein-Zebu crosses) was screened every two months by ELISA during a period of two years for IgG antibodies against 19 infectious disease agents. Two hundred and ninety five sera were collected from 157 young animals (0-4 months of age), 1037 sera from 292 developing animals (4-36 months of age) and 1468 sera from 259 producing animals (> 36 months of age). The results indicate that the difference in ELISA between positive and negative tests is associated with the overall prevalence of positive tests. When the prevalence of positive tests is low the difference between positive and negative tests is greater than when the prevalence is intermediate or high. This means that ELISA, presumably other serological tests for IgG antibodies,... Tipo: Info:eu-repo/semantics/article Palavras-chave: Serological screening; Cattie diseases; ELISA. Ano: 1993 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84781993000200014 SEROLOGICAL SCREENING FOR INFECTOUS CATTLE DISEASES: III. CHOICE OF SENTINEL ANIMALS Ciência Rural Rojas,José Alfonso Barajas-; Riemann,Hans; Franti,Charles. A herd of Cattle (Holstein-Zebu crosses) was screened bimonthly for two years by ELISA for IgG antibodies to infectious disease agents. The herd was composed of 3 age groups: Young animals ( < 4 months of age), developing animals (4-36 months of age) and producing animals ( &gt; 36 months of age). Ali young animals received colostrum within two hours after birth. The overall consistency of ELISA results, i. e agreement between two consecutive tests was about the same for the three age groups and was lowest for infections of intermediate prevalence (40-50%). The interpretation of changes in seroprevalence is most straight forward for young animals. Young animals positive at their first test reflect the immune status of their mothers while young... Tipo: Info:eu-repo/semantics/article Palavras-chave: ELISA; Seroconversion; Young; Sentinels; Infectious diseases. Ano: 1993 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84781993000200015 Registros recuperados: 5 Primeira ... 1 ... Última

Empresa Brasileira de Pesquisa Agropecuária - Embrapa Todos os direitos reservados, conforme Lei n° 9.610 Política de Privacidade Área restrita		Embrapa Parque Estação Biológica - PqEB s/n° Brasília, DF - Brasil - CEP 70770-901 Fone: (61) 3448-4433 - Fax: (61) 3448-4890 / 3448-4891 SAC: https://www.embrapa.br/fale-conosco