Hematological and immunological development from birth to six months of age in Holstein calves / Desenvolvimento hematológico e imunológico em bezerros Holandeses do nascimento aos seis meses de idade

The hematological and immunological development of calves from birth to 6 months of age was performed by hemogram and cellular phenotype. Ten male Holstein calves were assessed in 13 moments: before colostrum intake (D0), every 2 days until the 10th day of life (D2 to D10), at the 15th day after birth (D15), and then monthly up to 6 months (D180). Calves presented hemoconcentration on day (D) 0 and showed a gradual decrease in hematimetric rates until D180. The inversion of the neutrophilic for lymphocytic profile was observed on D4. The percentage of CD3+ cells on D10 was higher than D30 up to D180. The number of CD4+ and CD8+ cells did not change between time points. The number of CD21+ lymphocytes was significantly higher at early time points of D0 up to D15, compared on D30 until D150. In conclusion, the neonatal period was marked by stress leukogram in the first 4 days, and low number of B lymphocytes. These might be risk factors for bacterial infections responsible for navel inflammation and diarrhea. The increase in the number of B cells from 30 days of age demonstrated that the calves were functional and able to generate an immune response.(AU)

O desenvolvimento hematológico e o imunológico de bezerros do nascimento aos seis meses de idade foram avaliados por meio hemograma e imunofenotipagem dos linfócitos. Para tanto, 10 bezerros machos Holandeses foram avaliados em 13 momentos: antes da ingestão do colostro (D0), a cada dois dias até o 10º dia (D2 a D10), 15º dia (D15) e, em seguida, mensalmente até seis meses de idade (D180). Os bezerros apresentaram hemoconcentração em D0 e decréscimo gradual dos índices hematimétricos até D180. A inversão do perfil neutrofílico para linfocítico foi observada em D4. Os valores de CD3+ (%) em D10 foram maiores que aqueles observados em D30 até D180. CD4+ e CD8+ não apresentaram alterações entre os momentos. Os linfócitos B CD21+ aumentaram significativamente a partir dos primeiros momentos D0 até D15, em comparação com os momentos subsequentes D30 até D150. Em conclusão, o período neonatal foi caracterizado pelo leucograma de estresse nos primeiros quatro dias e o baixo número de linfócitos B. Esses fatos podem ser considerados como fatores de risco para infecções bacterianas responsáveis pelas inflamações umbilicais e pela diarreia. Por outro lado, o aumento de células B após os 30 dias de vida demonstrou que os bezerros foram capazes de gerar uma resposta imune.(AU)

Excretion of Brucella abortus vaccine B19 strain during a reproductive cycle in dairy cows

This paper aimed to determine the excretion period of B19 vaccine strain during a complete reproductive cycle (from estrus synchronization, artificial insemination, pregnancy and until 30 days after parturition) of dairy cows from 3 to 9 years old that were previously vaccinated from 3 to 8 months. Three groups were monitored with monthly milk and urine collection during 12 months: G1 with seven cows from 3 to 4 years old; G2 with three cows from 5 to 6 years old; and G3 with four cows from 7 to 9 years old. Urine and milk samples were submitted to bacteriological culture and urine and PCR reactions for detection of Brucella spp. and PCR-multiplex for B19 strain identification. Ring test (RT) was also performed in the milk samples, and serum samples were tested by buffered acidified plate antigen test (BAPA). All animals were serologically negative at BAPA and Brucella spp. was not isolated from both urine and milk samples. RT revealed 13/210 (6.2%) positive milk samples. PCR reactions detected DNA of Brucella spp. in 86/420 (20.5%) samples. In urine it was found a significantly higher frequency (35.2%; 74/210) than in milk (5.7%; 12/210), more frequently from the estrus to 150 days of pregnancy and after parturition (6.7%; 10/150), and from 150 days of pregnancy to parturition (3.4%; 2/60), and they were all identified as B19 strain. In three groups, intermittent excretion of B19 strain was detected mainly in urine samples, which confirmed its multiplication and persistence in cows for until 9 years.