Mortalidade

O ensaio foi iniciado com 549 animais com 78 dias de idade, sendo estes divididos pelos 2 tratamentos. No dia 159, quando foi dado por terminado o ensaio, estavam presentes apenas 526 animais, tendo durante a realização deste morrido 23 animais.

Na tabela 15, podemos observar o número de animais mortos em cada tratamento, sendo que o tratamento no qual ocorreram mais mortes foi no dos animais vacinados, com 13 baixas,

Avaliação dos efeitos da vacinação contra Actinobacillus pleuropneumoniae em suínos na engorda

44

representando 4,51% do número de animais iniciais. No tratamento controlo morreram 10 animais representado estes 3,83 % dos animais que iniciaram o ensaio.

Tabela 15: Taxa de mortalidade durante o ensaio por tratamento

Estes resultados não apresentam diferenças na mortalidade entre os 2 tratamentos (P> 0,05), o que não coincide com os resultados obtidos por Gozio et al. (2006) que obtiveram diferenças estatísticas na taxa de mortalidade, sendo esta de 1,39% nos animais vacinados e de 4,17% nos animais de controlo. No trabalho de Bosch et al. (2012) as diferenças também foram significativas, tendo a taxa de mortalidade dos animais vacinados sido de 2,81%, enquanto que a dos animais controlo foi de 10,73 %. Também Bilic et al. (2000) obtiveram diferenças significativas, tendo neste caso a mortalidade dos animais do grupo vacinado sido de 0,96 % e nos animais de controlo de 5,79 %. Nestes 3 trabalhos as taxas de mortalidade dos animais vacinados foram inferiores às dos animais do grupo não vacinado. No nosso caso não houve quaisquer diferenças nas taxas de mortalidade em ambos os tratamentos. Provavelmente, a não ocorrência de qualquer surto da doença na exploração e, em particular nos animais do ensaio, não permitiu que os animais vacinados e, portanto, imunes ao agente infeccioso, mostrassem vantagens comparativas. Tratamento 2 Controlo Vacina Dia 78 261 288 Dia 159 251 275 Mortes 10 13 Taxa mortalidade (%) 3,83 4,51 Ns

Conclusão

8 Conclusão

As infecções respiratórias provocadas pelo App estão amplamente distribuídas pelos principais países produtores de suínos. Para minimizar os riscos desta infecção se disseminar por todo o efectivo, algumas explorações optam por realizar a vacinação contra o App.

Neste trabalho avaliaram-se os efeitos da aplicação de uma vacina contra o App, comparando os resultados produtivos de animais vacinados com os dos animais não vacinados. Na comparação dos resultados produtivos deste ensaio, verificou-se que não houve diferenças estatísticas significativas (P> 0,05) entre os dois tratamentos. Este resultado pode ser explicado pela não ocorrência de nenhum surto da doença durante a realização do ensaio. Os resultados produtivos (peso de abate, GMD, IC e mortalidade) dos 2 grupos de animais foram melhores quando comparados com os resultados obtidos nas explorações dos principais países produtores de porcos. Também a avaliação feita em matadouros não revelou quaisquer tipos de lesões dignas de destaque.

Num futuro estudo, sobre o efeito da vacinação contra o App, seria interessante realizar o ensaio numa exploração com evidências sorológicas do agente e em que os animais no matadouro apresentem lesões compativeis.

Avaliação dos efeitos da vacinação contra Actinobacillus pleuropneumoniae em suínos na engorda

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