RELATIVE EFFECT OF TEMPERATURE AND MOISTURE ON THE DEVELOPMENT OF STRONGYLE EGGS TO INFECTIVE LARVAE IN BOVINE PATS IN ARGENTINA

To determine the most efficient microclimatic factors in bovine faeces that could explain the rate of development of parasitic nematode spec ies, experimental pats were deposited in three locations (sun, shade a nd laboratory) in central-west Argentina during summer, autumn and win ter seasons. Faecal water content (FWC) and temperature inside the pat s were recorded during the duration of the experimental periods. The m ean temperature and minimal values of FWC explained 54% of the variabi lity of the rate of development of Haemonchus (third-stage larvae per 100 eggs) and mean maximal temperature and minimal FWC values were the two main factors regulating Cooperia development (R(2) = 0.42). Rainf all was the third factor. No microclimatic component explained the dev elopment of Ostertagia in our experiments.