Baermannization of Dictyocaulus spp. from faeces of cattle, sheep and donkeys

Faeces were collected per rectum from calves infected with Dictyocaulus viviparus (D.v.), from lambs infected with Dictyocaulus filaria (D.f.) and donkeys infected with Dictyocaulus arnfieldi (D.a.). In one experiment, the influence of storage temperature before Baermannization was investigated. Recovery rate for D.v. was approximately 80% after 24 h at 4 degrees C or 16 degrees C but only 40% at 20 degrees C. After two days at 20 degrees C the rate had fallen to 20%. Recovery rates for D.f. decreased so markedly during the first 12 h at 4, 16 and 20 degrees C that storage can not be recommended. Losses in the recovery rates of D.a. appeared insignificant after 48 h at 4 degrees C but not at 16 degrees C and 20 degrees C. In experiment II the time taken for larvae to emerge from a 10-g sample as well as the sedimentation time in Baermann tubes was investigated. The bulk of the D.v. larvae remained in the faeces for about 10 h whereas D.f. larvae emerged during the first few hours. D.a. larvae were intermediate in this respect. Sedimentation of the bulk of larvae from all three species took place within a few hours with the modified Baermann technique used.