Avaliação do parasitismo gastrointestinal por nemátodes e céstodes em ovinos das raças Merina Branca e Merina Preta
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2021
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Tradicionalmente e, cada vez mais, a nível mundial a ovinocultura utiliza como fonte
primária de alimentação as pastagens. Contudo, é principalmente nestes ambientes que
proliferam os nemátodes e céstodes gastrointestinais, responsáveis por 40% das perdas
que ultrapassam em custos, só em Portugal, cerca de cinco milhões de euros.
Com o presente trabalho pretendeu-se avaliar a prevalência de nemátodes e
céstodes gastrointestinais, respetivas cargas parasitárias, bem como a necessidade de
desparasitação em ovinos das raças autóctones portuguesas Merina Branca e Merina
Preta. Para tal foram analisadas amostras de fezes de 243 ovinos da raça Merina Branca
e 70 ovinos da raça Merina Preta, colhidas respetivamente em 13 e 7 explorações na
região do Alentejo. As amostras foram analisadas pela técnica de Mini-Flotac para a
identificação e quantificação dos ovos de parasitas.
Verificou-se que 91% e 83% dos animais das raças Merina Branca e Merina
Preta, respetivamente, se encontravam parasitados com um ou mais géneros de
parasitas. Os parasitas mais frequentes foram os estrongilídeos gastrointestinais (87%
Merina Branca; 80% Merina Preta) seguidos dos géneros Strongyloides (19% Merina
Branca; 34% Merina Preta;), Nematodirus (21% Merina Branca; 9% Merina Preta),
Moniezia (17% Merina Branca; 9% Merina Preta) e Trichuris (3% Merina Branca; 1%
Merina Preta). A mediana da carga de ovos foi de 300 OPG na raça Merina Branca e
188 OPG na raça Merina Preta. As diferenças de prevalência e cargas parasitárias
observadas não foram estatisticamente significativas e não permitiram inferir sobre
diferenças na resistência ao parasitismo gastrointestinal entre as duas raças. No que
respeita a necessidade de desparasitação, com base no grau de infeção parasitária
determinado, classificado como leve em 57 % dos animais e moderado a grave em 43%,
a administração de anti-helmínticos seria dispensável na maioria dos casos, justificandose
o tratamento seletivo dos restantes animais.
Traditionally, and increasingly worldwide, sheep farming uses pastures as a primary source of food. However, it is mainly in these environments that gastrointestinal nematodes and cestodes proliferate, which are responsible for 40% of the losses that exceed in costs, in Portugal, around five million euros. This study aimed to assess the prevalence of gastrointestinal nematodes and cestodes, their parasite load, as well as the need for deworming in sheep of the Portuguese autochthonous breeds Merina Branca and Merina Preta. Fecal samples from 243 Merina Branca and 70 Merina Preta sheep, collected in 13 and 7 farms in the Alentejo region, respectively, were analyzed by the Mini-Flotac technique to identify and quantify parasite eggs. It was found that 91% and 83% of the Merina Branca and Merina Preta sheep, respectively, were parasitized with one or more genera of parasites. The most frequent parasites were gastrointestinal strongyles (87% Merina Branca; 80% Merina Preta) followed by the genera Strongyloides (19% Merina Branca; 34% Merina Preta;), Nematodirus (21% Merina Branca; 9% Merina Preta), Moniezia (17% Merina Branca; 9% Merina Preta) and Trichuris (3% Merina Branca; 1% Merina Preta). The median egg load was 300 EPG in the Merina Branca breed and 188 EPG in the Merina Preta breed. The differences in prevalence and parasite loads observed were not statistically significant and did not allow inferring differences in resistance to gastrointestinal parasitism between the two breeds. Regarding the need for deworming, based on the degree of parasitic infection determined, classified as mild in 57% of the animals and moderate to severe in 43%, the use of anthelmintics would be dispensable in most cases, while the remaining animals could benefit from selective treatment.
Traditionally, and increasingly worldwide, sheep farming uses pastures as a primary source of food. However, it is mainly in these environments that gastrointestinal nematodes and cestodes proliferate, which are responsible for 40% of the losses that exceed in costs, in Portugal, around five million euros. This study aimed to assess the prevalence of gastrointestinal nematodes and cestodes, their parasite load, as well as the need for deworming in sheep of the Portuguese autochthonous breeds Merina Branca and Merina Preta. Fecal samples from 243 Merina Branca and 70 Merina Preta sheep, collected in 13 and 7 farms in the Alentejo region, respectively, were analyzed by the Mini-Flotac technique to identify and quantify parasite eggs. It was found that 91% and 83% of the Merina Branca and Merina Preta sheep, respectively, were parasitized with one or more genera of parasites. The most frequent parasites were gastrointestinal strongyles (87% Merina Branca; 80% Merina Preta) followed by the genera Strongyloides (19% Merina Branca; 34% Merina Preta;), Nematodirus (21% Merina Branca; 9% Merina Preta), Moniezia (17% Merina Branca; 9% Merina Preta) and Trichuris (3% Merina Branca; 1% Merina Preta). The median egg load was 300 EPG in the Merina Branca breed and 188 EPG in the Merina Preta breed. The differences in prevalence and parasite loads observed were not statistically significant and did not allow inferring differences in resistance to gastrointestinal parasitism between the two breeds. Regarding the need for deworming, based on the degree of parasitic infection determined, classified as mild in 57% of the animals and moderate to severe in 43%, the use of anthelmintics would be dispensable in most cases, while the remaining animals could benefit from selective treatment.
Descrição
Orientação: Helga Waap
Palavras-chave
MESTRADO INTEGRADO EM MEDICINA VETERINÁRIA, MEDICINA VETERINÁRIA, VETERINÁRIA, OVINOS, PARASITAS, SISTEMA DIGESTIVO, VETERINARY MEDICINE, SHEEP, PARASITES, DIGESTIVE SYSTEM, RAÇA MERINA PRETA, BLACK MERINO SHEEP, RAÇA MERINA BRANCA, WHITE MERINO SHEEP