Dinámica de los niveles de infección por estrongilidos digestivos en bovinos a pastoreo

a total of 54 young cattle were monthly submitted, during 1 year to coprological (mac master technique) and hematogical (microhematocrit) examination. statistical differences in the fecal egg count (epg) of strongylids was found between sexes, corresponding the highest values to the males (p<0.04). a significant positive correlation (rs = 69, p < 0.05) between strongylid prevalence and the percentage of animals with high worm burden (？wormy animals？) was found. a significant negative correlation between the hematocrit values and the epg counts was found (rs = 0.29, p < 0.05). the hematocrit values resulted lower in males than in females, but without statistical differences. some animals resulted negatives in many or in the total of coprological evaluations, independently of breed or sex, indicating a individual response. this animals has been classified as high responder against the strongylid infection, being this manifestation of resistance genetic in nature and therefore heritable, the importance of this fact in animal selection as a mechanism of parasite control, is discussed.