De. Jacobs et al., AN EVALUATION OF ABAMECTIN GIVEN AT TURNOUT AND 6 WEEKS AFTER TURNOUTFOR THE CONTROL OF NEMATODE INFECTIONS IN CALVES, Veterinary record, 136(15), 1995, pp. 386-389
Two groups of 16 set-stocked calves were used to evaluate a new strate
gy for the prevention of parasitic bronchitis and parasitic gastroente
ritis. One group was left untreated while the calves in the other were
treated with abamectin at 0.2 mg/kg at turnout and again six weeks la
ter. The treatment prevented the output of nematode eggs and lungworm
larvae in faeces for at least 70 days. The number of infective larvae
subsequently appearing on the pasture was reduced by 90.2 per cent and
the infectivity of the pasture (as monitored by tracer calves) by 96.
0 to 99.8 per cent in the case of Dictyocaulus viviparus, 88.2 to 99.2
per cent for Ostertagia ostertagi and 69.3 to 98.1 per cent for Coope
ria oncophora. Parasitic bronchitis occurred in the control calves and
both bronchitis and gastroenteritis in the tracer calves grazing the
paddock grazed by the control calves, but no disease occurred either i
n any of the calves treated with abamectin or in the tracer calves gra
zing the paddock grazed by these calves.