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Bovine genetic resistance effects on biological traits of Rhipicephalus (Boophilus) microplus.
Biegelmeyer, P; Nizoli, L Q; da Silva, S S; dos Santos, T R B; Dionello, N J L; Gulias-Gomes, C C; Cardoso, F F.
Afiliação
  • Biegelmeyer P; Department of Animal Science, Federal University of Pelotas, 96160000 Capão do Leão, RS, Brazil.
  • Nizoli LQ; Faculty of Veterinary, Federal University of Pelotas, 96160000 Capão do Leão, RS, Brazil.
  • da Silva SS; Faculty of Veterinary, Federal University of Pelotas, 96160000 Capão do Leão, RS, Brazil.
  • dos Santos TR; Faculty of Veterinary, Federal University of Pelotas, 96160000 Capão do Leão, RS, Brazil.
  • Dionello NJ; Department of Animal Science, Federal University of Pelotas, 96160000 Capão do Leão, RS, Brazil; National Council for Scientific and Technological Development, 71605-001 Brasília, DF, Brazil.
  • Gulias-Gomes CC; Embrapa Southern Region Animal Husbandry, 96401970 Bagé, RS, Brazil.
  • Cardoso FF; Department of Animal Science, Federal University of Pelotas, 96160000 Capão do Leão, RS, Brazil; Embrapa Southern Region Animal Husbandry, 96401970 Bagé, RS, Brazil; National Council for Scientific and Technological Development, 71605-001 Brasília, DF, Brazil. Electronic address: fernando.cardoso@em
Vet Parasitol ; 208(3-4): 231-7, 2015 Mar 15.
Article em En | MEDLINE | ID: mdl-25648284
This study aimed to verify the influence of bovine genetic resistance on biological traits of the Rhipicephalus (Boophilus) microplus tick. Genetic resistance or susceptibility was determined according to breeding values for tick counts, predicted using a dataset of 9007 Hereford and Braford (Hereford×Zebu) bovines naturally infested and raised under extensive production systems in southern Brazil. From a total of 974 Braford heifers born in 2008, 20 were classified as genetically tick-resistant and 20 classified as genetically tick-susceptible, and used to obtain the ticks samples used in this study. The 40 heifers were exposed to four subsequent artificial infestations with approximately 20,000 larvae at 14-day intervals. From the 19th to 23rd day of each infestation tick counts were performed on the left body side of the heifers. Engorged ticks were manually collected on the day of highest observed burden after each infestation. Tick counts on susceptible heifers were 5.5, 10.5, 11.1 and 6.9 times larger than on resistant heifers, respectively, after the first, second, third and fourth artificial infestations. In the third infestation, ticks from resistant heifers showed lower egg production index (P<0.0001) than ticks from susceptible heifers. In the fourth infestation, ticks from susceptible group showed higher egg mass weight (P<0.05) and nutrient index (P<0.0001) than ticks from resistant heifers. Tick initial weights showed a positive association with egg production index in susceptible heifers (P<0.05) and a negative association in the resistant group (P<0.05), suggesting a host defense mechanism that reduces the conversion efficiency of ingested blood to eggs in engorged ticks from resistant cattle. This shows that bovine genetic tick resistance, in addition to affecting the number of ticks carried by the animals, also affected the egg mass weight, egg production and nutrient indexes of ticks. The results of the present study imply that the selection of resistant animals could be used as a strategic tool for tick control in production systems, reducing infestation levels on cattle and environment.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Infestações por Carrapato / Doenças dos Bovinos / Predisposição Genética para Doença / Rhipicephalus Limite: Animals Idioma: En Revista: Vet Parasitol Ano de publicação: 2015 Tipo de documento: Article País de afiliação: Brasil País de publicação: Holanda

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Infestações por Carrapato / Doenças dos Bovinos / Predisposição Genética para Doença / Rhipicephalus Limite: Animals Idioma: En Revista: Vet Parasitol Ano de publicação: 2015 Tipo de documento: Article País de afiliação: Brasil País de publicação: Holanda