Studies on multispecific resistance of gastrointestinal nematodes to benzimidazoles on dairy-goat farms.

Multispecific resistance to benzimidazoles was studied in three selected farms. These farms had bred dairy goats for more than 15 years. The helminths were introduced with the goats at the establishment of the farms which afterwards remained isolated. Nematode resistance could then be related to their own management practices. Faecal egg count tests and egg hatch assays were performed to assess intensity of resistance. The generic (infective larvae in faecal cultures) and specific richness (adult worms) were assessed. The resistant species were Trichostrongylus colubriformis, Teladorsagia circumcincta, Haemonchus contortus and Oesophagostomum venulosum. Faecal egg count reduction tests and egg-hatch assays did not match exactly. Faecal larval counts after treatments gave a distorted picture of multispecific resistance: Haemonchus and Oesophagostomum were very largely over represented. The number of species found in the three farms was relatively low compared with other reports in goat farms of the area. This reduction of diversity might also be due in part to characteristics of breeding management and history (use of permanent pasture and introduction of goats at the establishment of farm).

Respiratory and pulmonary haemodynamic changes during experimental organophosphate poisoning in goats.

Five French Alpine goats received 2 mg kg-1 of dichlorvos (DDVP) by intravenous injection and 0.15 mg kg-1 of atropine sulphate 5-10 min later. Ventilatory mechanics, gas exchanges, pulmonary haemodynamics and pulmonary vascular resistance (PVR) were measured before treatment, 5 min after DDVP injection and 5 min after atropine injection. Within 2 min of DDVP administration, all the goats showed acute respiratory distress, excitation and slight muscle fasciculations. A post-inspiratory pause was recorded in 3 goats. Hypersecretion of saliva or nasal discharge was not observed. Dynamic compliance and heart rate decreased significantly and total pulmonary resistance, pulmonary artery and wedge pressures increased significantly. On the other hand, minute ventilation, arterial oxygen and carbon dioxide tensions were not significantly altered by DDVP. Atropine treatment reversed all the clinical and functional parameters, with the exception of the central nervous and muscular signs, which disappeared within 12 h. It was concluded that experimental DDVP toxicosis induced changes in the mechanics of breathing and pulmonary haemodynamics associated with diffuse bronchoconstriction and cardiac insufficiency respectively.