Abundância e fatores de risco de Dermatobia hominis (Linnaeus JR., 1781) (Díptera: Cuterebridae) em bovinos em Pecuária Orgânica na Fazendinha Agroecológica Km 47, RJ

Abstract

Studies on larvae of Dermatobia hominis have been described, but no data were found on this infestation in dairy cattle raised under organic conditions. This study aimed to provide information on this parasitic skin disease in an organic nursery, verifying the location and distribution of larvae on the body surface of cattle, to determine the frequency of infestation in relation to sex, age and coat color, beyond the influence of climatic factors. The herd consisted of 40 crossbred dairy Zebu x European, divided into lots of young and adult animals. Inspection was carried out fortnightly (915 inspections) with mapping for the presence of larvae on the body surface, from September 2009 to August 2010 in the "FAZENDINHA AGROECOLÓGICA KM 47”. The results indicated incidence of parasitism in females (average 21.98 against 8.37 in males), in males a higher number of nodules on the right side (4.46 against 3.90 on the left side), where the right posterior superior region (RPDS ) was the most infested. In females highest number of nodules on the left and right anterior superior (RADS). The infestation in adults (average 31.55) was higher than in young animals in lactation were less infested (average 8.01) in both groups of young animals infested the side was left in the group where breast-feeding region most affected was the anterior right superior (RADS), and the weaned group was the left anterior superior (RAES) in the adult group was the most infested area to the anterior right superior (RADS), the coat was more infested painted white to black (average 36.69 per animal), the coats were the least infested red hues typical (average 14.13 per animal) and light brown and dark (12:33). The highest rates occurred in November and December while the lowest in June and July. With respect to rainfall and relative humidity, each increment of 1mm ³ of water caused a mean increase of 1.03 in the relative risk of occurrence of dermatobiosis and every one degree increase in average temperature, there was an average increase of 1 , 14 in the relative risk for infestation. The results were significant for all climatic variables studied. It can be argued that this ideal breeding animals are brown fur and red hues typical. One can not say that there is influence of lateral decubitus on the right-external body infected. The climatic factor that most influenced the dermatbiosis was temperature. The organic management system used was able to keep the animals safe level of infection where the parasite load was not able to cause clinical disease in catlle