Efficacy of Oxibendazole As an Anthelmintic in Cattle

OF WASHINGTON, VOLUME 42, NUMBER 2, JULY 197.5 135

G. W. Elam. 1963. Critical tests of thia- levamisole-piperazine mixture as an anthel- benclazole as an anthelmintic in the horse. mintic in the horse. Am. J. Vet. Res. 35: Am. J. Vet. Res. 24: 1217-1222. 67-72. —. 1965. The use of anthelmintics for Lyons, E. T., and J. H. Drudge. 1970. Crit- parasite control in the horse. Vet. Med./Sm. ical tests on dl-tetramisole against internal An. Clin. 60: 243-247. parasites of the horse. Am. J. Vet. Res. 31: . 1972. Endoparasitisms. In Equine Medi- 1477_148(). cine and Surgery, 2nd Ed., American Veter- Trace, J. C., W. H. Hcppcrle, R. J. Eppley, inary Publications, Wheaton, 111., p. 157-179. L. Sender, and G. T. Edds. 1962. New , E. T. Lyons, and T. W. Swerc/ek. broad spectrum anthelmintic for horses. Vet. 1974. Critical tests and safety studies on a Mecl. 57: 144-146.

Efficacy of Oxibendazole as an Anthelmintic in Cattle

H. HERLICH1 : ,.; United States Department of Agriculture «v.»

ABSTRACT: In a critical test of the activity of Oxibendazole at dose rates of 5 and 10 mg/kg in cattle, efficacy against adult Haemonchus contortus, Ostertagia ostertagi, Trichostrongylus axei, Tricho- strongylus colubriformis, Cooperia oncophora, and Oesophagostomum radiatum ranged from 85 to 100%. Efficacy was slightly poorer against H. contortus and C. oncophora at the lower dosage. Ac- tivity at 10 mg/kg against 3- and 7-day-old worms of these species was assessed in a controlled test. Efficacy was above 90% against H. contortus, T. colubriformis, and C. oncophora, 76 and 87% against T. axei, and 34% against O. ostertagi; there was no activity against O. radiatum.

A new anthelmintic, Oxibendazole (methyl dose of the following mixture of nematode 5 n-propoxy-2-benzimidazole carbonate), has larvae: 17,000 H. contortus, 180,000 O. oster- been reported (Theodorides et al., 1973; tagi, 120,000 T. axei, 90,000 C. oncophora, Theodorides and Chang, 1974) to be highly 100,000 T. colubriformis, and 10,000 O. radia- effective against the adult stages of the nema- tum. After 28 days, oxibenclazole (supplied by todes, Haemonchus contortus, Ostertagia oster- Smith, Kline and French, Inc., Philadelphia, tagi, Trichostrongylus axei, Trichostrongylus Pennsylvania) was given per os to five calves colubriformis, Cooperia spp., and Oesophago- at a dose rate of 5 mg/kg body weight and to stomtim radiatum in eattle. They (loc. cit.) five calves at 10 mg/kg. Feces were collected also reported that the drug was highly effective every 24 hr for 4 days and examined by the against immature and adult stages of species technique of Swanson et al., (1940). After 4 from the same genera that parasitize sheep. days, residual worm counts were determined at Their results were based on controlled tests in necropsy by techniques of Porter (1942) and which limited numbers of animals were used. Herlich (1956). This report presents the results of critical tests Twelve 3-month-olcl calves were used in with oxibenclazole against adult nematodes in controlled tests against 3- and 7-day-old worms. cattle and a controlled test against immature Each calf was inoculated with a single dose of stages. the following infective larvae: 15,000 H. contortus, 40,000 O. ostertagi, 40,000 T. axei, Procedure 30,000 T. colubriformis, 50,000 C. oncophora, and 5,000 O. radiatum. Three days after inoc- Ten 4-month-old calves were used for the ulation, four calves were treated with oxibenda- critical tests. Each was inoculated with a single zole at 10 mg/kg; 7 days after inoculation four other calves were similarly treated; and four 1 Animal Parasitology Institute, Agricultural Research Service, Beltsville, Maryland 20705. calves were left untreated to serve as controls.

Table 1. Anthelmintic activity of oxibendazole against adult gastrointestinal nematodes in 10 calves treated at a dosage of 5 or 10 mg/kg.

Dosage and Worms eliminated after treatment animal No. H.c. O.o. T.a. T.c. C.o. O.r. 5 mg/kg: 714 270 18,900 42,000 2,400 31,080 2,072 715 190 30,800 42,000 2,800 27,160 196 730 530 26,180 33,600 4,200 16,520 1,568 731 460 39,100 51,200 3,300 14,180 1,210 732 420 17,500 29,800 3,090 28,420 1,415 Avg. 374 26,496 39,720 3,158 23,472 1,292

i y 714 27 13 0 0 1,960 0 715 0 133 0 0 4,620 0 730 80 93 0 0 6,160 0 731 45 122 0 0 1,820 0 732 50 60 0 0 3,200 0 A vs. 40 (89) 84 (99) 0 (100) 0 (100) 3,552 (85) 0 (100)

Worms eliminated after treatment H) mg/kg: 668 480 37,925 47,930 1,800 14,485 1,680 ( 93 260 49,105 75,325 4,200 15,520 4,600 694 340 34,645 50,600 6,000 13,795 230 695 240 39,905 41,745 3,800 21,850 4,280 G96 360 30,900 52,600 3,900 14,120 1,760 Avg. 336 38,496 53,640 3,940 15,954 2,510 Worms recovered at necropsy* 668 0 1,620 840 0 30 0 ( 93 0 270 60 0 60 0 694 0 360 120 0 90 0 695 0 210 0 0 0 0 C90 0 460 0 0 20 0 Avg. 0 (100) 584 (98) 204 (99) 0 (100) 40 (99) 0 (100) H.c. = H.. contorttis; O.o. = O. ostertaxi; T.a. = T. trxei; T.c. = T. cohibriformifi; C.o. = C. oncophora; O.r. = O. radi- (itiim. * Figures in parentheses represent percentage of efficacy.

Necropsy was performed on all calves 28 days ostertagi at the lower dosage. Because intact after inoculation to determine residual worm specimens of H. contortus were infrequently counts. recovered, the estimate of numbers expelled was based on posterior ends of worms only. Results and Discussion The fact that this species was so severely affec- ted by hostal digestion suggests that estimates Worm count data for calves in the critical tests of the numbers expelled were conservative and are shown in Table 1. Nearly all worms (90% that the efficacy of oxibendazole at 5 mg/kg or more) were expelled within 48 hr. Most of was probably greater than 89%. Calf 732, the worms recovered during the next 48 hr which was passing eggs of Bunostomum phle- were C. oncophora and lesser numbers of O. botomum at the time of inoculation, expelled ostertagi. seven hookworms and had none at necropsy. The drug was 85 to 100% effective against These results confirm those reported by Theo- adults of all species at both dose rates; it was clorides et al. (1973) and Theodorides and slightly less active against H. contortus and O. Chang (1974).

Table 2. Anthelmintic activity oi oxibendazole against 3- and 7-day-old gastrointestinal nematodes in eight calves treated at a dosage of 10 mg/kg.

Worms recovered at necropsy" Animal No. H.c. O.o T.a. T.c. G.o. O.r. Group I— -Treated 3 days postinoculation 751 400 18,400 6,200 0 180 1,320 750 820 18,200 3,600 0 60 1,980 767 140 11,400 1,600 0 150 2,380 768 1,060 33,600 7,600 60 600 2,135 Avg. 605 (91) 20,400 (34) 4,750 (76) 15 (99) 248 (99) 1,954 (0)

Group II——Treated 7 days postinoculation* 757 520 27,200 2,600 0 720 2,960 758 280 29,600 3,800 0 2,460 1,170 769 240 6,200 600 0 1,290 1,980 770 480 18,600 2,800 0 1,060 2,425 Avg. 380 ( 94 ) 20,400 (34) 2,450 (87) 0 (100) 1,383 (96) 1,748 (0)

Group III — Untreated controls 759 6,480 38,200 15,400 1,500 26,400 1,710 771 9,140 27,400 21,800 4,500 33,900 1,800 773 3,560 27,600 21,200 3,900 39,900 2,100 774 6,740 29,800 19,200 4,500 24,900 1,380 Avg. 6,480 30,750 19,400 3,600 31,275 1,748 H.c. = H. contortus; O.o. = O. ostertagl; T.a. = T. uxei; T.c. = T. colubrijormia; C.o. — C. oncophora; O.r. = O. nidi- atum. * Figures in parentheses represent percentage of efficacy.

Results of the controlled test with immature Porter, D. A. 1942. Incidence of gastrointes- worms are shown in Table 2. Efficacy against tinal nematodes of cattle in the southeastern 3- and 7-day-old H. contortus, T. colubriformis, United States. Am. J. Vet. Res. 3: 304-308. and C. oncophora ranged from 91 to 99%, com- Swanson, L. E., D. A. Porter, and J. W. Con- nelly. 1940. Efficacy of nonconditioned paring favorably with the anthelmintic action phenothiazine in removing worms from the against adults. However, activity against O. alimentary canal of cattle. JAVMA 96: 704- ostertagi and T. axei was poor, and the drug 707. was totally ineffective against O. radiatum. Theodorides, V. J., and J. Chang. 1974. The results with these three species are in sharp Oxibendazole—a new effective nematocide contrast to the reported (Theodorides et al., against the gastrointestinal nematodes of cat- 1973) activity of oxibendazole against imma- tle. Proc. 3rd Int. Cong. Parasit. 3: 1406- ture stages of the same or closely related para- 1407. sites in sheep. However, precise details of the , , C. J. DiCuollo, G. M. Grass, R. C. Parish, and G. C. Scott. 1973. Oxi- developmental stages and species of nematode bendazole, a new broad spectrum anthelmintic were not given for that study, and subsequent effective against gastrointestinal nematodes of work by that group has yielded results (pers. domestic animals. Brit. Vet. J. 129: 97-98. comm.) similar to mine. Literature Cited Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the Herlich, H. 1956. A digestion method for post- product by the U. S. Department of Agriculture, mortem recovery of nematodes from rumi- and does not imply its approval to the exclusion nants. Proc. Helm. Soc. Wash. 23: 102-103. of other products that may be suitable.