Levels of natural resistance to Boophilus microplus (Acari Ixodidae) in Carora breed bulls

• Roy D. Meléndez ^[1] ; Alfredo Coronado ^[1] ; Franklin Mujica ^[1] ; Franco Cerutti ^[2] ; Ortelio Mosquera ^[3]
  1. [1] Universidad Centroccidental
  2. [2] Universitá de Milano Facoltá di Medicina Veterinaria
  3. [3] Ministerio de Agricultura y Cría Servicio Autónomo de Sanidad Animal del Estado Lara

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• Localización: Revista de Biología Tropical, ISSN 0034-7744, Vol. 46, Nº. 3, 1998, págs. 691-696
• Idioma: inglés
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• Resumen

  • Boophilus microplus infestation is one of the most serious limitations to cattle industry in tropical regions, even though bovines show natural resistance to ticks. This resistance was evaluated in Cross-bred Carora Bulls (CCB) a tropicalized dairy breed from Venezuela. Seven CCB were experimentally infested with B. microplus larvae, "Mozo" strain, they were considered tick-naive because they had never been infested with ticks. The mean inoculum size applied on each bull was 6 477 larvae. After life cycle was completed adult female body weight (BW), egg mass weight (EW), egg hatching rate (%EH), and reproductive index (RI) were recorded. Results revealed a high variability in the levels of resistance to B. microplus. Thus, one animal showed greater resistance (Dunnett, p< 0.05) for the analyzed parameters in contrast with three non-resistant bulls. The others had moderate resistance. The trait "resistance" should be included togheter with other traits often used in genetic selection of cattle.