Background
The knowledge on bovine vaccines against respiratory viruses on bronchoalveolar fluid cells is scarce.
Objective
To compare the effects of a commercial intranasal (IN) and intramuscular (IM) vaccine against bovine respiratory disease (BRD) complex viruses on bronchoalveolar fluid cells of healthy heifers.
Methods
21 healthy heifers were assigned to three treatment groups: control (CO, N = 7), intranasally vaccinated (IN) (n = 7), and intramuscularly vaccinated (IM) (n = 7). The IN group received 1 mL of the commercial vaccine in each nostril once containing attenuated BoHV-1, bPIV-3, and BRSV. The IM group was vaccinated with two doses of 2 mL with an interval of 21 days of the commercial vaccine containing attenuated BoHV-1, bPIV-3, and BRSV plus inactivated BVDV. At day 0 (D0), before the first vaccine dose, and at D3, D7, and D21, after the last vaccine dose, airway bronchoscopy was performed to observe local irritation and collect bronchoalveolar lavage fluid (BALF). The bronchoalveolar count, cytological evaluation, bronchoalveolar cell oxidative metabolism, and total bronchoalveolar IgA and IgG were measured.
Results
The IN vaccine increased neutrophil cellularity at D7 and D21 and total IgA at D3 in BALF. Total IgA in BALF also increased at D3 and oxidative metabolism of bronchoalveolar cells at D21 lowered compared to the CO group. Following IM vaccination there was no alteration of immunoglobulins or cell oxidative metabolism in BALF. Both vaccines reduced the number of alveolar macrophages.
Conclusion
Both vaccines induced bronchoalveolar inflammation during the establishment of the vaccine immunity, which was more expressive in the IN protocol.
O uso de probióticos a base de leveduras melhora o ganho de peso e o sistema imunológico de bovinos frente a grandes desafios imunológicos, no entanto permanece a dúvida se seu uso também apresentaria efeito em desafios mais tênues. Desta maneira, o presente trabalho verificou se o uso de probiótico a base de Enterococcus faecium e Saccaromyces cerevisiae via oral interfere na imunidade inata e no peso de bezerros sadios, em fase de crescimento, alimentados principalmente com silagem de milho. Para tanto, 12 bezerros da raça Jersey (120 kg ±50 kg e 4-7 meses de idade), foram alocados nos grupos controle (n=6) ou tratamento (n=6), de acordo com a oferta de probiótico (2g/dia, via oral) durante 45 dias. Nos dias 0, 15, 30 e 45, os animais foram submetidos a pesagens, exames clínicos, e colheita de sangue para realização de hemograma e mensuração do metabolismo oxidativo neutrofílico. Observou-se que, o probiótico promoveu pequeno e pontual incremento na função neutrofilica sanguínea (P=0,10, D15), incremento nos valores de hematócrito e hemoglobina (P=0,03 e 0,05, D45), além de maior ganho de peso nas fases iniciais da administração do suplemento (P=0,05), permitindo concluir que o suplemento é benéfico para animais em fase de adaptação de trocas de dieta e de manejo, mesmo quando estes desafios são tênues.
Treatment of the bovine respiratory disease complex (BRDC) can elicit high bacterial resistance and stress to steers in a feedlot. Therefore, the present study aimed to evaluate three therapeutic protocols with long-acting antibiotics against BRDC naturally acquired in steers finished in feedlot. In a total of 80 animals finished in a feedlot, 18 steers showed clinical signs compatible with BRDC (mucopurulent nasal secretion, lung auscultation alteration, leukocytosis, and decrease of dry matter intake). These animals were randomly treated: marbofloxacin in a single dose (M1), marbofloxacin in two doses (M2), or ceftiofur in a single dose (C1) on Day 0. The clinical score of pneumonia, hemogram, daily food intake, and body weight were analyzed during 7 days. On slaughter day (Day 100), the body weight and frequency of lungs with pneumonia was evaluated. On Day 7, M2 showed absence of pneumonia, and M1 and C1 still showed a clinical score of mild pneumonia (P = 0.01). On day 2 and day 3 M2 showed a higher dry matter intake than others treatments (P = 0.05). C1 showed a lower body weight than others group on day 1 and 2 (P = 0.05). The C1 and M1 showed a higher pneumonia frequency than M2 (P = 0.02). The M2 slaughter weight was numerically higher than the other treatments. We conclude the marbofloxacin in two doses eliminated the pneumonia ́s clinical symptoms and allowed the animals to return the productivity earlier than other protocols.
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