The aims of this study were to evaluate the seasonal variation and frequency distribution of Rhipicephalus (Boophilus) microplus, Haematobia irritans, and Dermatobia hominis on crossbred heifers under field conditions in the northeast of Minas Gerais state, southeastern Brazil. From November 2007 to September 2009 (23 months), 40 heifers aged months were divided into groups A ( Holstein × 3/4 Gir) and B ( Holstein × Gir) and had the monthly infestation estimated along with the climatic conditions. The mean maximum and minimum temperatures were 28.5 and 19°C, respectively. The ectoparasites were present on animals in all months of the year. The levels of ticks on the animals were low ( ticks/animal), with the highest density in midwinter. The temperature was the climatic factor that most influenced the tick levels. The population of H. irritans ( flies/animal) and D. hominis ( larvae/animal) on heifers was more influenced by rainfall and exhibited two population peaks during the year. Holstein heifers harbored significantly more H. irritans and D. hominis than Holstein heifers. The results are discussed considering the most appropriate periods to apply ectoparasiticides and the genetic make-up of the animals. 1. Introduction The ectoparasites of cattle in Brazil are a significant hindrance to national livestock. Among the primary ectoparasites are the tick Rhipicephalus (Boophilus) microplus and the flies Haematobia irritans and Dermatobia hominis. Together, the losses caused by these parasites are estimated at more than US$ 2.5 billion per year [1, 2]. Cattle kept under field conditions tend to be parasitized simultaneously by different species of ectoparasites. Proposals to combat more than one parasite at once are more economical and more operationally feasible and may have greater acceptance by farmers [3]. Most control programs are based primarily on the application of ectoparasiticides. The application of these compounds in a strategic manner reduces the amount of ectoparasiticides used and prevents population peaks, keeping the parasite burdens below the levels that cause economic losses. However, for satisfactory results, the number and timing of applications must take into account the biological and ecological characteristics of each ectoparasite in the region in which the program will be implemented. Another very attractive strategy is the insertion of genes from parasite-resistant breeds to use the animals’ immune systems to help fight off the parasites [4]. Several studies have shown that Bos indicus is more resistant to ectoparasites than
References
[1]
D. S. Rodrigues and R. C. Leite, “Economic impact of Rhipicephalus (Boophilus) microplus: estimate of decreased milk production on a dairy farm,” Arquivo Brasileiro de Medicina Veterinaria e Zootecnia, vol. 65, no. 5, pp. 1570–1572, 2013.
[2]
L. Grisi, R. C. Leite, J. R. Martins et al., “Reassessment of the potential economic impact of cattle parasites in Brazil,” Brazilian Journal of Veterinary Parasitology, vol. 23, no. 2, pp. 150–156, 2014.
[3]
L. N. Domingues, Práticas de controle e perfil de suscetibilidade de Haematobia irritans irritans (Linnaeus, 1758) (Diptera: Muscidae) e Rhipicephalus ( Boophilus ) microplus (Canestrini, 1887) (Acari: Ixodidae) à cipermetrina e clorpirifós na mesorregi？o do Triangulo Mineiro e Alto Paranaíba, MG, 2010, UFMG, Belo Horizonte: Brazil, 2011.
[4]
M. J. Mackinnon, K. Meyer, and D. J. S. Hetzel, “Genetic variation and covariation for growth, parasite resistance and heat tolerance in tropical cattle,” Livestock Production Science, vol. 27, no. 2-3, pp. 105–122, 1991.
[5]
P. N. Wambura, P. S. Gwakisa, R. S. Silayo, and E. A. Rugaimukamu, “Breed-associated resistance to tick infestation in Bos indicus and their crosses with Bos taurus,” Veterinary Parasitology, vol. 77, no. 1, pp. 63–70, 1998.
[6]
P. Tugwell, E. C. Burns, and J. W. Turner, “Brahman breeding as a factor affecting the attractiveness or repellency of cattle to the horn fly,” Journal of Economic Entomology, vol. 62, no. 1, pp. 56–57, 1969.
[7]
R. Heitzman, J. Martinez, and R. Wells, “Trichlorfon (Metrifonate),” in Residues of Some Veterinary Drugs in Animals and Foods: Monographs Prepared by the Fifty-Forth Meeting of the Joint FAO/WHO Expert Committee on Food Additives (JECFA), pp. 103–114, FAO/WHO, Geneva, Switzerland, 2000.
[8]
T. R. Adkins Jr., “Residues in cattle tissues following back-line and spray applications of trichlorfon,” Journal of Economic Entomology, vol. 59, no. 6, pp. 1423–1425, 1966.
[9]
W. S. Lima, M. F. Ribeiro, and M. P. Guimaraes, “Seasonal variation of Boophilus microplus (Canestrini, 1887) (Acari: Ixodidae) in cattle in Minas Gerais state, Brazil,” Tropical Animal Health and Production, vol. 32, no. 6, pp. 375–380, 2000.
[10]
G. P. Oliveira and M. M. Alencar, “Resistência de bovinos de seis graus de sangue Holandês-Guzerá ao carrapato (Boophilus microplus) e ao berne (Dermatobia hominis),” Arquivo Brasileiro de Medicina Veterinária e Zootecnia, vol. 42, no. 2, pp. 127–135, 1990.
[11]
R. T. Powell and T. J. Reid, “Project tick control,” Queensland Agricultural Journal, vol. 12, no. 6, pp. 279–300, 1982.
[12]
P. R. Gomes, M. R. Honer, and R. L. Silva, “Intensidade parasitária de larvas de Dermatobia hominis (L. JR. 1781) (Diptera: Cuterebridae) em bovinos de diferentes ra？as criadas extensivamente na regi？o de cerrado do Mato Grosso do Sul,” Revista Brasileira de Parasitologia Veterinária, vol. 5, no. 2, pp. 103–106, 1996.
[13]
A. Gomes, J. C. Souza, A. M. Resende, and J. B. E. Curvo, “Distribui？？o corporal e sazonalidade do berne (larva de D. hominis) em bovinos tratados ou n？o com flor de enxofre,” Pesquisa Agropecuária Brasileira, vol. 23, no. 8, pp. 825–829, 1988.
[14]
L. G. Brito and G. E. Moya-Borja, “Flutua？？o sazonal de Dermatobia hominis em peles bovinas oriundas de matadouro,” Pesquisa Veterinária Brasileira, vol. 20, no. 4, pp. 151–154, 2000.
[15]
W. F. Chamberlain, “Dispersal of horn flies. III effect of environmental factors,” The Southwest Entomol, vol. 9, no. 1, pp. 73–78, 1984.
[16]
N. O. Morgan, “Autecology of the adult horn fly, Haematobia irritans (L.) (Diptera: Muscidae),” Ecology, vol. 45, pp. 728–736, 1964.
[17]
W. G. Bruce, The History and Biology of the Horn Fly, Haematobia irritans (Linnaeus): with Comments on Control, vol. 157 of Technical Bulletin (North Carolina Agricultural Experiment Station), 1964.
[18]
L. G. F. Lima, S. H. V. Perri, and A. P. Prado, “Variation in population density of horn flies (Haematobia irritans) (L.) (Diptera: Muscidae) in Nellore cattle (Bos indicus),” Veterinary Parasitology, vol. 117, no. 4, pp. 309–314, 2003.
[19]
A. T. M. Barros, “Dynamics of Haematobia irritans irritans (Diptera:Muscidae) infestation on cattle in the Pantanal, Brazil,” Memorias do Instituto Oswaldo Cruz, vol. 96, no. 4, pp. 445–450, 2001.
[20]
J. R. Martins, J. A. Porci, J. A. Vieira, and J. A. Porciúncula, “Dinamica populacional da mosca do chifre Haematobia irritans (Diptera: Muscidae) em S？o Gabriel, regi？o centro-oeste do Rio Grande do Sul,” Revista Brasileira de Medicina Veterinária, vol. 11, no. 2, pp. 99–101, 2002.
[21]
A. A. Guglielmone, O. S. Anziani, A. J. Mangold, R. E. Giorgi, M. M. Volpogni, and S. G. Flores, “Seasonal variation of Haematobia irritans (Diptera: Muscidae) in a recently infested region of central Argentina,” Bulletin of Entomological Research, vol. 87, no. 1, pp. 55–59, 1997.
[22]
R. D. Hughes, “Rainfall as a cause of mortality in a dung breeding fly,” Journal of the Australian Entomological Society, vol. 18, pp. 323–327, 1979.
[23]
C. D. Steelman, E. E. Gbur, G. Tolley, and A. H. Brown Jr., “Individual variation within breeds of beef cattle in resistance to horn fly (Diptera: Muscidae),” Journal of Medical Entomology, vol. 30, no. 2, pp. 414–420, 1993.
[24]
I. Bianchin and R. G. O. Alves, “Mosca dos chifres, Haematobia irritans: comportamento e danos em vacas e bezerros Nelore antes da desmama,” Pesquisa Veterinária Brasileira, vol. 22, no. 3, pp. 109–113, 2002.
[25]
I. Bianchin, W. W. Koller, and E. Detmann, “The seasonality of Haematobia irritans in central Brazil,” Pesquisa Veterinaria Brasileira, vol. 26, no. 2, pp. 79–86, 2006.
[26]
E. Castro, A. Gil, J. Piaggio et al., “Population dynamics of horn fly, Haematobia irritans irritans (L.) (Diptera: Muscidae), on Hereford cattle in Uruguay,” Veterinary Parasitology, vol. 151, no. 2–4, pp. 286–299, 2008.
[27]
A. A. Guglielmone, E. Curto, O. S. Anziani, and A. J. Mangold, “Cattle breed-variation in infestation by the horn fly Haematobia irritans,” Medical and Veterinary Entomology, vol. 14, no. 3, pp. 272–276, 2000.
[28]
V. G. Mateus, “Ecologia y control de Dermatobia hominis (L. Jr 1781) en Colombia,” in Seminário Sobre Ecologia y Control de los Parasitos Externos de Importancia Economica que Efectam el Ganado en America Latina, pp. 141–146, International Center for Tropical Agriculture, Cali, Colombia, 1977.
[29]
I. Bianchin, W. W. Koller, R. G. O. Alves, and E. Detmann, “Efeito da mosca-dos-chifres, Haematobia irritans (L.) (Diptera: Muscidae), no ganho de peso de bovinos Nelore,” Ciência Rural, vol. 34, no. 3, pp. 885–890, 2004.
[30]
A. T. M. Barros, “Recomenda？？es para o controle da mosca-dos-chifres no Pantanal,” Comunicado Técnico, vol. 10, pp. 1–4, 1992.
[31]
M. R. Honer, I. Bianchin, and A. Gomes, “Programa de controle da mosca-dos-chifres. I. Brasil Central,” Comunicado Técnico, vol. 34, pp. 1–3, 1990.
[32]
R. C. Leite, A. P. Cunha, A. C. P. P. Bello, L. N. Domingues, and E. Bastianetto, “Controle dos ectoparasitos em bovinocultura de corte,” in Bovinocultura de Corte, A. V. Pires, Ed., vol. 2, pp. 1171–1196, FEALQ, Piracicaba, Brazil, 2010.
[33]
L. N. Domingues, A. P. Cunha, A. C. P. P. Bello, E. Bastianetto, and R. C. Leite, “Epidemiologia das principais parasitoses de bovinos no Brasil Central. Parte II: controle estratégico de parasitos,” V&Z em Minas, vol. 28, no. 97, pp. 27–37, 2008.
[34]
M. B. Molento, F. S. Fortes, A. Buzatti et al., “Partial selective treatment of Rhipicephalus microplus and breed resistance variation in beef cows in Rio Grande do Sul, Brazil,” Veterinary Parasitology, vol. 192, no. 1-3, pp. 234–239, 2013.
[35]
J. R. Martins, D. E. Evans, V. H. Ceresér, and B. L. Corrêa, “Partial strategic tick control within a herd of European breed cattle in the state of Rio Grande do Sul, southern Brazil,” Experimental and Applied Acarology, vol. 27, no. 3, pp. 241–251, 2002.
[36]
F. A. de Almeida, F. D. O. Alari, M. C. Z. Seno, M. M. de Lima, S. T. Nascimento, and M. C. Neto, “Efficiency of partial treatment of cattle infested with horn fly using 40% diazinon,” Revista Brasileira de Parasitologia Veterinaria, vol. 22, no. 4, pp. 554–558, 2013.
