Response of cattle treated with a fenbendazole slow release bolus to challenge from nematodes the following season.
Nematode infection of cattle treated in their first year at pasture with the fenbendazole slow release bolus ('Bolus group') was compared during the second year with that of untreated cattle. Ostertagia was the most prevalent parasite associated with Cooperia. Except for the Dictyocaulus spp. which caused clinical signs of bronchitis in the 'Bolus' group, the infection during the second year resulted in a moderate response of the cattle whatever the group. Rises in both pepsinogen and gastrin levels were correlated with the number of Ostertagia L3 on herbage. Damages in the abomasal mucosa were more frequent and severe in the 'Bolus' group where more inflammatory signs were observed in spite of a smaller number of worms. Nevertheless, the differences in total weight gains were not significant thanks to a compensatory effect during the second part of the grazing season in the 'Bolus' group. Hypotheses related to a minimum threshold of infection during the first year necessary to develop high enough protection during the second year are discussed. The pathological effects of gastrointestinal nematodes seem to vary more according to the inflammatory response than to the number of worms.
Kerboeuf
D
D
INRA, Station de Pathologie Aviaire et de Parasitologie, Unité d' Helminthologie, Nouzilly, France.
Hoste
H
H
Hubert
J
J
Le Stang
J P
JP
D000821:Animal Feed; D000818:Animals; D000969:Antinematodal Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D002417:Cattle; D002418:Cattle Diseases; D003692:Delayed-Action Preparations; D004021:Dictyocaulus / Q000302:isolation & purification; D005273:Fenbendazole / Q000008:administration & dosage* / Q000627:therapeutic use; D005755:Gastrins / Q000097:blood; D009348:Nematoda / Q000302:isolation & purification*; D009349:Nematode Infections / Q000453:epidemiology / Q000517:prevention & control / Q000662:veterinary*; D010028:Ostertagia / Q000302:isolation & purification; D010270:Parasite Egg Count; D010435:Pepsinogens / Q000097:blood; D006109:Poaceae; D015995:Prevalence; D012621:Seasons; D013997:Time Factors
D000969:Antinematodal Agents; D003692:Delayed-Action Preparations; D005755:Gastrins; D010435:Pepsinogens; D005273:Fenbendazole