Efficacy of fenbendazole against adult Dictyocaulus viviparus in experimentally infected calves.

Fenbendazole, methyl-5(phenylthio)-2-benzimidazolecarbamate, a new broad-spectrum anthelmintic, was evaluated against the adult Dictyocaulus viviparus, lungworm of cattle, in artificially infected calves. At a dosage of 5 mg/kg of body weight, fenbendazole removed 100% of the worms if given as an oral suspension, and 99.7% of the worms if given as a feed additive.     

Anthelmintic activity of Croton zehntneri and Lippia sidoides essential oils

Because of the development of anthelmintic resistant populations, the search for new drugs is essential to maintain the productivity of small ruminants. The aim of this study was to evaluate the anthelmintic activity of Croton zehntneri and Lippia sidoides essential oils and their major constituents, anethole and thymol. The effects of these oils and their constituents were determined by in vitro assays with the eggs and larvae of the sheep gastrointestinal nematode Haemonchus contortus. The two essential oils were evaluated on intestinal nematodes of mice at 800 mg kg(-1) dose. In the last experiment, the mice were treated with larger doses of L. sidoides, 1200 and 1600 mg kg(-1). The essential oils and their constituents prevented more than 98% of the H. contortus eggs from hatching at a concentration of 1.25 mg ml(-1) and inhibited more than 90% of H. contortus larval development at a concentration of 10 mg ml(-1). At a concentration of 800 mg kg(-1), the two essential oils were 46.3% and 11.64% effective against Syphacia obvelata and Aspiculuris tetraptera. At 1200 and 1600 mg kg(-1), L. sidoides essential oil's efficacy on the mouse worm burden was 57.6% and 68.9%, respectively. The fact that L. sidoides essential oil was almost 70% effective against mouse intestinal nematodes indicates it should be evaluated against gastrointestinal nematodes of sheep and goats.     

Anthelmintic activity of continuous low doses of fenbendazole into the rumen of sheep

Fenbendazole (FBZ) was continuously infused for 30 days into the rumen of 103 lambs which had mature or developing benzimidazole-susceptible or thiabendazole-resistant Haemonchus contortus and susceptible Trichostrongylus colubriformis infections. Ovicidal, larvicidal and adulticidal activities were exhibited against benzimidazole-susceptible and benzimidazole-resistant H. contortus worms by FBZ at a dose level of greater than or equal to 0.2 mg kg-1 body weight day-1. Reasonably consistent high level efficacy against H. contortus was obtained with dose levels greater than 0.4 mg kg-1. Excellent control of susceptible T. colubriformis worms was achieved with the lowest dose tested of 0.4 mg kg-1 day-1. The intraruminal infusion critical study method is a tool to determine the feasibility of incorporating a candidate anthelmintic compound in a continuous sustained-release rumen device formulation. The anthelmintic profile of FBZ obtained by low-level intraruminal administration suggests that it would be a potential candidate.     

Efficacy of fenbendazole against helminth parasites of poultry in Uganda

Summary Fenbendazole 4% (Panacur, Hoechst) administered in feed was used to treat chickens infected withAscaridia galli, Heterakis gallinarum andRailletina spp. It was also used to treatSyngamus trachea in broiler birds. There was a marked drop in helminth egg counts in the faeces on the second day of treatment and the faeces became negative by the seventh day after the last treatment. Post-mortem examination 15 to 21 days later showed that the drug was 100% effective againstAscaridia galli andHeterakis gallinarum at 10 mg/kg. However, for complete removal ofRailletina spp. 15 mg/kg was required. Similarly 20 mg/kg fenbendazole was effective againstSyngamus trachea. It was concluded that fenbendazole is suitable for the treatment of the important intestinal and tracheal worms of poultry, a dose of 15 to 20 mg/kg for 3 consecutive days being recommended for use under field conditions.

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Eficacia Del Fenbendazole Contra Helmintos De Aves Domesticas En Uganda

Presumen Se administró Fenbendazole 4% (Panacur, Hoechst) en el alimento, para tratar aves infectadas conAscaridia galli, Heterakis gallinarum y Railletina spp. También se utilizó la droga para tratar pollos de engorde infectados conSyngamus trachea. Hubo un descenso marcado en el conteo de huevos de helmintos al segundo día del tratamiento, y las heces fueron negatives 7 días después del último tratamiento. El examen pos-mortem 15 y 21 días después del tratamiento mostró que la droga fue 100% efectiva contraAscaridia galli y Heterakis gallinarum en dosis de 10 mg/kg. Sin embargo, para el control deRailletina spp. 1a dosis se incrementó a 15 mg/kg. Similarmente, 20 mg/kg de Fenbendazole fueron efectivas contraSyngamus trachea. Se concluye, que el Fenbendazole es efectivo contra el tratamiento de los principales parásitos intestinales y traqueales de las aves domésticas, en dosis de 15 a 20 mg/kg, administrado por días consecutivos, en casos de campo.

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Efficacite Du Fenbendazole Contre Les Helminthes Parasites Des Volailles En Ouganda

Résumé Le Fenbendazole 4 p. 100 (Panacur, Hoechst) administré dans l'alimentation a été utilisé pour le traitement de poulets infectés parAscaridia galli, Heterakis gallinarum etRailletina spp. Il a été également utilisé contreSyngamus trachea chez les oiseaux de chair. On a observé une baisse marquée dans la numération des oeufs dans les fèces dès le deuxième jour du traitement et ces fèces étaient devenues négatives le septième jour après le dernier traitement. L'examen post-mortem pratiqué de 15 à 20 jours plus tard a montré que le produit était efficace à 100 p. 100 contreAscaridia galli etHeterakis gallinarum à 10 mg/kg. Cependant, il a fallu en arriver à la dose de 15 mg/kg pour obtenir la complète élimination deRailletina spp. De même le Fenbendazole à la dose de 20 mg/kg a été effectif contreSyngamus trachea. Il en est conclu que ce produit convient pour le traitement des helminthes intestinaux et trachéaux des volailles, la dose de 15 à 20 mg/kg pendant 3 jours consécutifs étant recommandée lors de son utilisation sur le terrain.

     

Expulsion of small strongyle nematodes (cyathostomin spp) following deworming of horses on a stud farm in Sweden

This study was conducted on a stud farm in Sweden to investigate the species composition of cyathostomins expelled in the faeces of horses after deworming using three different anthelmintic preparations. Twenty-seven horses excreting > or = 200 strongyle eggs per gram faeces (EPG) were divided into three comparable groups and dewormed on day 0 with either of following compounds: 0.2 mg ivermectin per kg body weight (bw), 19 mg pyrantel pamoate per kg bw or 7.5 mg fenbendazole per kg bw. For each of the 3 days following anthelmintic treatment faeces was collected from individual horses and subsamples were fixed in formalin. Four days after the anthelmintic treatment all horses were re-treated with ivermectin and faeces was collected on day 5. Individual subsamples from each of the four sampling occasions were examined for cyathostomin nematodes. Sixty-three to 270 worms per horse were identified to the species level. The majority of the worms recovered were expelled during the first day from horses treated with ivermectin or pyrantel pamoate, and during the second day from horses treated with fenbendazole. Fifteen cyathostomin species were identified and the six most prevalent were Cylicocyclus nassatus, Cyathostomum catinatum, Cylicostephanus longibursatus, Cylicocyclus leptostomus, Cylicostephanus minutus and Cylicostephanus calicatus. These species composed 91% of the total burden of cyathostomins. The number of species found per horse ranged from 6 to 13, with an average of 9. No significant differences in species composition or distribution were found between the treatment groups. On day 5, i.e. 1 day after the last ivermectin treatment, 93% of the adult worms were recovered from horses in the fenbendazole group.This study showed that it was possible to identify cyathostomins expelled in faeces of dewormed horses, and that the most prevalent species corresponded to those found in autopsy surveys performed in other countries.     

The anthelmintic efficacy of fenbendazole against a mixed nematode infection in sheep.

Fenbendazole (methyl-5-(phenylthio)-2-benzimidazole carbamate) at dose rates of 5 mg/kg and above was 100 per cent effective in eliminating a naturally acquired Dictyocaulus filaria infection in sheep. The drug was 100 per cent effective in eliminating concurrent infections of adult Trichostrongylus axei, Haemonchus contortus, Haemonchus placei, Ostertagia circumcincta, Ostertagia ostertagii, Cooperia oncophora, Cooperia mcmasterii, Nematodirus spathiger, Neumatodirus filcollis, Oesophagostomum venulosum and Chabertia ovina. Fenbendazole was 93 per cent and 97 per cent effective at doses of 5 and 10 mg/kg respectively in removing infection with adult T colubriformis, and post-treatment worm-egg production was completely suppressed in surviving female worms. No adverse side-effects were observed in treated sheep at either of the two dose rates used.     

Ascaridia galli infections in free-range layers fed on diets with different protein contents

1. One hundred and twenty 17-week-old Lohman Brown hens were divided into 4 groups. Groups 1 and 3 were given a diet with 180 g protein/kg and groups 2 and 4 were given a diet with 140 g protein/kg. Groups 1 and 2 were orally infected with 500 (50) embryonated Ascaridia galli eggs. 2. Marked differences in mean weekly weight gain for the 4 groups were observed. 3. Hens given 140 g protein/kg had a significant lower mean worm burden of adult A. galli worms and a significant lower weight gain compared to the group given 18 g protein/kg. 4. There was no significant difference in faecal egg counts between the 2 parasitised groups. 5. The egg production did not differ significantly between any of the groups. 6. The results of this study indicate that the amount of dietary protein in the diet has an effect on the establishment of A. galli infections in the gut of layers kept under free range conditions.     

Anthelmintic activity of Trianthema portulacastrum L. and Musa paradisiaca L. against gastrointestinal nematodes of sheep

Evaluation of anthelmintic effects of Trianthema (T.) portulacastrum L. (Aizoaceae) whole plant and Musa (M.) paradisiaca L. (Musaceae) leaves against prevalent gastrointestinal worms of sheep was done that may justify their traditional use in veterinary clinical medicine. In vitro anthelmintic activity of the crude aqueous methanolic extract (CAME) of both the plants was determined using mature female Haemonchus (H.) contortus and their eggs in adult motility assay (AMA) and egg hatch test (EHT), respectively. In vivo anthelmintic activity of crude powder (CP) and CAME in increasing doses (1.0-8.0 g kg(-1)) was determined in sheep naturally infected with mixed species of nematodes using fecal egg count reduction test (FECRT) and larval counts. The study design also included untreated as well as treated controls. Fecal egg count reduction and larval counts from coprocultures were performed pre- and post-treatments to assess the anthelmintic activity of the plants. CAME of T. portulacastrum and M. paradisiaca showed a strong in vitro anthelmintic activity and pronounced inhibitory effects on H. contortus egg hatching as observed through AMA and EHT, respectively. Both plants exhibited dose and time dependent anthelmintic effects on live worms as well as egg hatching. M. paradisiaca (LC(50)=2.13 μg mL(-1)) was found to be more potent than T. portulacastrum (LC(50)=2.41 μg mL(-1)) in EHT. However, in vivo, maximum reduction in eggs per gram (EPG) of faeces was recorded as 85.6% and 80.7% with CAME of T. portulacastrum and M. paradisiaca at 8.0 g kg(-1) on 15th day post-treatment, respectively as compared to that of Levamisole (7.5 mg kg(-1)) that caused 97.0% reduction in EPG. All the species of gastrointestinal nematodes (GINs), i.e. Haemonchus contortus, Trichostronglyus spp., Oesophagostomum columbianum and Trichuris ovis which were prevalent, found susceptible (P<0.01) to the different doses of CP and CAME of both plants. The data showed that both T. portulacastrum and M. paradisiaca possess strong anthelmintic activity in vitro and in vivo, thus, justifying their use in the traditional medicine system of Pakistan.     

The effect of levamisole and albendazole on some enzymes of Ascaridia galli and Heterakis gallinae

Ascaridia galli and Heterakis gallinae obtained from the common fowl Gallus gallus were exposed to 10(-2)-10(-5)M levamisole and albendazole; both compounds caused death of the parasites in vitro. The effect of the drugs was investigated on homogenates of the treated worms. Albendazole, at 10(-2)M, inhibited oxaloacetate reduction by 67 and 53% and malate oxidation by 21 and 17% in A. galli and H. gallinae, respectively, whereas 10(-4)M levamisole completely inhibited malate dehydrogenase activity in both directions in the two parasites. Lactate dehydrogenase was not affected significantly by either anthelmintic. Aldolase activity was diminished by 57 and 32% in A. galli and H. gallinae, respectively, with 10(-4)M levamisole. Levamisole at 10(-4)M also inhibited the activity of acid and alkaline phosphomonoesterase and cholinesterase. Albendazole had no significant effect on these enzymes in either parasite. Malate dehydrogenase and cholinesterase activity of the host tissue (intestine and caecum) was also reduced significantly with 10(-2) and 10(-3)M levamisole. These studies indicated a multiple mode of action of levamisole and albendazole.     

Characteristics of a flubendazole resistant isolate of Oesophagostomum dentatum from Germany.

Two controlled tests were performed to investigate the benzimidazole resistance of a nodular worm isolate "GIBZ" from a pig breeding farm in Germany. In Trial I, groups of five pigs, artificially infected with Oesophagostomum larvae isolated from that farm were treated with flubendazole at a single dose of 5 mg kg(-1) bodyweight (BW) or remained untreated. In Trial II, three groups of three pigs each infected with larvae after a further laboratory passage of this isolate were treated with flubendazole either at a single dose of 5 mg kg(-1) BW or at a divided dose of 1.5 mg kg(-1) BW daily for 5 consecutive days, or with fenbendazole at a single dose of 5 mg kg(-1) BW, the fourth infected group remained untreated. The respective doses of anthelmintics were mixed with a small amount of feed and administered to individual pigs in both trials. Fecal egg counts before and after treatment and post-mortem worm burdens 7 days after (last) treatment were examined to assess the anthelmintic efficacies. Only infections with Oesophagostomum dentatum were found in both trials. In Trial I, the mean worm count reduction by flubendazole was 30% as compared to the untreated controls. In Trial II, flubendazole administered at a single or divided dose reduced the mean worm burden by 0 and 85%, respectively, whereas fenbendazole was 100% effective. These results establish resistance to flubendazole in the isolate "GIBZ" of O. dentatum. The failure to reveal side resistance to fenbendazole may be explained by that the currently recommended dose rate of this compound is supra-optimal for porcine nodular worms.     

Response of gilts with delayed puberty to pregnant mare serum gonadotropin or estrogen

The effect of pregnant mare serum gonadotropin (PMSG) or estradiol cyclopentylpropionate (EC) on the induction of estrus, duration of estrus, and serum progesterone concentration after estrus was evaluated in 8 gilts with delayed puberty. Four gilts were given 500 IU of PMSG IM and 4 were given 2 mg of EC, IM. The inactive status of the ovaries at the time of treatment was verified by serum progesterone values of less than 0.5 ng/ml in serial samples collected before treatment. The 4 EC-treated gilts came into estrus at a mean of 3.5 days after treatment, but 1 of the gilts did not form corpora lutea. Three PMSG-treated gilts came into estrus at a mean of 4.0 days after treatment. The remaining PMSG-treated gilt remained anestrus and did not form corpora lutea. The mean duration of estrus in EC-treated gilts was 5.25 days compared with 2.0 days for PMSG-treated gilts (P less than 0.05). Serum progesterone concentrations were higher in PMSG-treated gilts than in EC-treated gilts at 8, 11, and 17 days after treatment (P less than 0.05).     

Study of the acetylcholinesterase activity of Ascaridia galli: kinetic properties and the effect of anthelmintics.

Acetylcholinesterase (EC 3.1.1.7) activity was demonstrated in whole worm homogenates of adult Ascaridia galli with acetylthiocholine as substrate. The pH optimum was not measurable because of an autohydrolysis of the substrate. The Michaelis constant (Km) was 4 mM with saturation by excess substrate. Optimum enzyme activity was noted at a protein concentration of 200 mg/ml assay medium and at a temperature of 37 degrees C. Arrhenius plot of temperature dependence of the enzyme activity showed an energy of activation (delta Ea) of 28.962 K joule/mole above, and 25.448 K joule/mole below, the transition temperature (37 degrees C). Complete inhibition by eserine (physostigmine), a specific and classical acetylcholinesterase inhibitor, established the identity of the enzyme. A marginally higher enzyme activity was observed in females than in males as well as in homogenates from worms of mixed sexes. The enzyme was markedly activated by divalent metal cations such as Fe2+, Mg2+, Cd2+, Cu2+, Zn2+ and Ca2+, while Co2+ and Mn2+ inhibited the activity. Piperazine adipate at a concentration of 10(-3) M caused 45.5% and albendazole, a benzimidazole anthelmintic, 37.5% inhibition in the enzyme activity, while levamisole and mebendazole proved to be practically ineffective, causing an inhibition of 12 and 9%, respectively.     

Evaluation of fenbendazole as an extended anthelmintic treatment regimen for swine

Fenbendazole was given in the feed to swine at a cumulative dosage of 9 mg/kg of body weight over a period of 3, 6, and 12 days to compare efficacy. Four treatment groups of ten 2- to 3-month-old pigs each, with a mean of 15 kg of body weight per group, received 3 mg of fenbendazole/kg/day for 3 days, 1.5 mg/kg/day for 6 days, 0.75 mg/kg/day for 12 days, and no medication. Medicated feed was scheduled so that all treated pigs reached the last day of treatment on the same day, thus making the time between the last treatment and necropsy equal for all groups. Ascaris suum and Trichuris suis were the target species, their presence before treatment being determined by fecal egg counts and at necropsy by worm counts. At necropsy, 9 control pigs were infected with A suum (mean of 18.0 worms/pig), and all control pigs had T suis infection (mean of 36.5 worms/pig). All 3 treatment schedules were 100% effective in removal of A suum; and for T suis, the 3-day regimen was 100% effective, the 6-day regimen, 99.2%, and the 12-day regimen, 91.0%.     

EFFECTIVENESS OF ANTHELMINTIC TREATMENTS AGAINST LEVAMISOLE-RESISTANT OSTERTAGIA

Adult worms from a population of Ostertagia consisting of 88% O. circumcincta and 12% O. trifurcata were found to survive a double drench (14 mg/kg) of levamisole. An anthelmintic assay on this population found that against levamisole the LD50 was 11.95 mg/kg and the LD99 was 67.75 mg/kg. Three benzimidazoles were also tested against this population and the LD50 and LD99 were respectively thiabendazole 11.8 and 144.9 mg/kg, oxfendazole 0.17 and 6.10 mg/kg and albendazole 0.08 and 2.55 mg/kg. The percentage of worms killed by the recommended dose rate was levamisole 24%; thiabendazole 91%; oxfendazole 99% and albendazole 99%.     

Further characterisation of a triple resistant field isolate of Teladorsagia from a Scottish lowland sheep farm

Anthelmintic efficacies against juvenile developing populations of Teladorsagia species that were known to be resistant to anthelmintics from all three broad spectrum families were examined using a controlled efficacy test. Fenbendazole (FBZ), levamisole (LEV), ivermectin (IVM), combinations of these anthelmintics and moxidectin (MOX) were assessed in parasite na?ve lambs artificially infected with 8,000 third stage larvae (Tci5) and treated orally 8-day post-infection with the compounds at the manufacturers recommended dose rates, FBZ, 5 mg/kg body weight (BW); LEV, 7.5 mg/kg BW; IVM, 0.2 mg/kg BW; MOX (0.2 mg/kg BW). The lambs were slaughtered 14-day post-treatment. The arithmetic mean worm burden reductions resulting from oral treatments with FBZ; IVM; LEV; FBZ+IVM; FBZ+LEV; FBZ, LEV+IVM or MOX were 36%, 82%, 38%, 86%, 60%, 88% and 97%, respectively. The results illustrate that combination treatments showed improved efficacies against the juvenile population compared to individually administered treatments but that these improvements were not wholly effective. Moxidectin was the only treatment that was over 95% effective, though caution should be noted when advising the use of MOX prophylactically since 3% of the infection still survived this treatment. Treatments directed at juvenile stages of Tci5 were less effective, with the exception of IVM, compared to a similar trial using Tci5 where the same treatments were directed against a predominantly adult population. No interaction was detected comparing the timings of treatments and its effectiveness with the exception of IVM (two-way ANOVA, p < 0.05). These findings suggest that, on the whole, the selection processes for anthelmintic resistance (AR) may occur at an early stage of development within the parasites, having severe implications for the early detection of AR.     

The anthelmintic effect of aqueous methanol extract of Combretum molle (R. Br. x. G. Don) (Combretaceae) in lambs experimentally infected with Haemonchus contortus

The aqueous methanol extract from the stem-bark of Combretum molle was evaluated for anthelmintic activity in lambs infected with Haemonchus contortus using faecal egg count (FEC) reduction assay. The extract showed a dose-dependent reduction in FEC in infected animals. At doses of 500, 1000 and 2000 mg kg(-1), the extract caused FEC reduction of 63%, 69.25% and 96.23%, respectively. Similarly, the standard anthelmintic (albendazole) at a dose of 200 mg kg(-1) produced FEC reduction of 99.24%. FEC reduction produced by the extract at doses of 500 and 1000 mg kg(-1) is below the minimum standard of 90% FEC recommended by the World Association for the Advancement of Veterinary Parasitology (WAAVP). However, there was no significant (P>0.05) difference between the means of groups treated with 1000 mg kg(-1) and 2000 mg kg(-1) compared to that of albendazole. In this study, C. molle has shown a promising anthelmintic activity against experimental haemonchosis. Nonetheless, further studies to evaluate its detailed toxicity are required for the plant extract to be developed into a useful anthelmintic drug. There is also the need to evaluate other parts of the plant (root, leaves, fruits, etc.) for the same effect.     

Oxfendazole--anthelmintic activity in Egyptian goats artificially infected with gastrointestinal nematodes.

The recently developed benzimidazole anthelmintic, oxfendazole, was tested against artificial nematode infestations in Egyptian goats using oral dosing at 4.5 and 2.8 mg/kg. A 100% clearance of mature and immature Haemonchus contortus, Trichostrongylus axei, Ostertagia circumcincta, Coopera curticei, Bunostomum trigonocephalum and Chabertia ovina was obtained at the 4.5 mg/kg level. Very high levels of clearance against the mature worms were obtained at 2.8 mg/kg but the drug was less effective against immature worms at the lower dose rate. PCV, hemoglobin concentration and total erythrocyte counts declined after infection but became significantly (P less than 0.001) raised in treated animal.     

In vivo anthelmintic activity of bruceine A and bruceine D from Brucea javanica against Dactylogyrus intermedius (Monogenea) in goldfish (Carassius auratus)

The present study was designated to ascertain the anthelmintic activity of the dried fruits of Brucea javanica and to isolate and characterise the active constituents. The methanol extract from the fruits of B. javanica showed significant anthelmintic activity against Dactylogyrus intermedius (EC(50) (median effective concentration) value=49.96 mg l(-1)). Based on this finding, the methanol extract was fractionated on silica gel column chromatography in a bioassay-guided fractionation affording two known quassinoids showing potent activity, bruceine A and bruceine D. Both bruceine A and D exhibited significant activity against D. intermedius with EC(50) values of 0.49 mg l(-1) and 0.57 mg l(-1), respectively, which were more effective than the positive control, mebendazole (EC(50) value=1.25 mg l(-1)). In addition, the 48-h median lethal concentration (LC(50)) for bruceine A and D against the host (Carassius auratus) was 10.6-fold and 9.7-fold higher than the EC(50) for D. intermedius. These results provide evidence that the isolated compounds might be potential sources of new anti-parasitic drugs for the control of Dactylogyrus. This is the first report on an in vivo anthelmintic investigation for B. javanica against D. intermedius.     

Anthelmintic efficacy of febantel combined with praziquantel against Ancylostoma tubaeforme, Toxocara cati, and Taenia taeniaeformis in cats

Forty cats, each harboring 2 or 3 parasitic infections (Ancylostoma tubaeforme, Toxocara cati, and/or Taenia taeniaeformis), were used to titrate the anthelmintic efficacy of a paste containing 3.4% febantel and 0.34% praziquantel. The cats were allotted into 4 groups (10 cats/group). For 3 consecutive days, the cats were given febantel/praziquantel at 5/0.5 mg/kg/day, 10/1 mg/kg/day, 15/1.5 mg/kg/day, or a blank paste vehicle (control) at 0.29 g/kg of body weight. The recommended dosage of 10 mg of febantel and 1 mg of praziquantel/kg cleared greater than or equal to 98% of the 3 helminth species.     

EFFICACY OF ANTHELMINTICS AGAINST CATTLE NEMATODES

The efficacies of fenbendazole and thiabendazole against artifically acquired cattle nematodes and the efficacies of fenbendazole, prabendazole and levamisole against naturally acquired cattle nematodes were studied in western Victoria. Fenbendazole significantly (P less than 0.05) reduced numbers of late and early fourth stage larvae (greater than 96%), artificially acquired Cooperla spp (100%) and naturally acquired adult Ostertagia ostertagi (98%) and Trichostrongylus axei (90%). Thiabendazole significantly reduced numbers of artificially acquired late fourth stage larvae (83%) and parbendazole significantly reduced numbers of adult O. ostertagi (72%) in one group of cattle. Fenbendazole was the most effective anthelmintic.