Goats from the Venezuelan northem arid zones were found infested by the following nematodes: Haemonchus contortus, Trichostrongylus axei, T. colubriformis, Cooperia curticei, Oesophagostomum columbianum, Skrjabinema ovis y Trichuris globulosa. The Shannon-Weaver index of diversity values oscillated between 0.045 and 1.73 bits (X = 1.16 ± 0.24 bits). The maximum value of montly diversity ranged from 1 to 2.80 bits (X = 2.49 ± 0.28 bits) and the equitability ranged from 0.045 to 0.67 (X = 0.44 ± 0.09). Parasitic associations were found among 1) T. axei, T. colubriformis and H. contortus, 2) T. colubriformis, H. contornus and O. columbianum and 3) T. colubriformis, S. ovis and T. globulosa. The above results suggest that in months when the diversity index is close to the maximum value and the equitability index is near unity, wide spectrum antihelmintic treatment should be used for poly-parasitized animals.
parasites; nematodes; goats; microecology; arid zones