Efficacy of febantel against abomasal nematodes and lungworms in cattle.
The efficacy of febantel at a dosage of 5 mg/kg (45.5% paste formulation) against inhibited early 4th-stage larvae (EL4) of Ostertagia ostertagi, other nematodes of the abomasum, and Dictyocaulus viviparus was investigated in 4- to 6-month-old Holstein calves that grazed on pasture heavily contaminated with parasites from February 24 to April 1, 1986 (36 days). In Louisiana, this is the first month of a 3-month period in which increasing numbers of inhibition-prone O ostertagi larvae are acquired, and infection risk with D viviparus may remain high. Three of 4 calves that died of lungworm infection during the pasture-exposure period were necropsied. Large numbers of abomasal nematodes, including inhibited O ostertagi larvae, and large numbers of D viviparus were recovered. Twenty-five calves were randomly allotted by equal distribution of body weight to 2 groups and treated on April 4: placebo-treated calves (n = 13) and febantel-treated calves (n = 12). Equal numbers of treated and control calves were killed at 6 and 7 days, respectively, after treatment. Mean numbers of O ostertagi in control cattle were: adults, 4,931; developing 4th-stage larvae (DL4), 1,119; and inhibited EL4, 3,410. Ostertagia lyrata, Trichostrongylus axei, Haemonchus sp, and D viviparus were well distributed in nearly all control calves. Percentage reduction of O ostertagi in treated calves, when compared with controls, was: adults, 83.6%; DL4, 57.8%; and inhibited EL4, 34.8%. Percentage reductions of other species were: O lyrata, 92.6%; T axei adults, 99.3% and 4th-stage larvae (L4), 100%; Haemonchus sp adults, 66.7%, and L4, 64%; D viviparus adults 90.6%, and immature forms, 97.1%.(ABSTRACT TRUNCATED AT 250 WORDS)
Williams
J C
JC
Department of Veterinary Science, Louisiana State University Agricultural Center, Louisiana Agricultural Experiment Station, Baton Rouge 70803.
Marbury
K S
KS
Eddi
C S
CS
Willis
E R
ER
Luther
D G
DG
D000018:Abomasum / Q000469:parasitology*; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy* / Q000469:parasitology; D004022:Dictyocaulus Infections / Q000188:drug therapy* / Q000469:parasitology; D004341:Drug Evaluation; D005243:Feces / Q000469:parasitology; D006146:Guanidines / Q000008:administration & dosage / Q000627:therapeutic use*; D010029:Ostertagiasis / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*; D010270:Parasite Egg Count / Q000662:veterinary; D014252:Trichostrongyloidiasis / Q000662:veterinary*
D006146:Guanidines; C017309:febantel