| epidemiology of dictyocaulus viviparus in louisiana (u.s.a.). | an epidemiological investigation was conducted during a 1-year period on a permanent pasture naturally contaminated with dictyocaulus viviparus and grazed by a varying number of yearling cattle. seasonal variation in pasture infectivity to cattle was monitored by monthly slaughter of tracer calves, slaughter of pairs of resident yearlings at 30-60-day intervals, herbage larval recovery and by counts of first stage larvae in feces (modified baermann technique) of resident cattle. a clinical outbr ... | 1989 | 2524929 |