morantel and Helminthiasis--Animal

The milbemycins are the only novel broad spectrum anthelmintic chemicals to reach the market place in the last 10 years. Many new systems for delivery and strategies for rational use have, however, been introduced. Boluses which are retained by virtue of specific gravity and by variable geometry are now available. They contain benzimidazoles, morantel, ivermectin and levamisole. Their release mechanisms involve preferential corrosion of a retaining metal core, constant diffusion from a laminated ethylene acetate sandwich, and a hydrostatic pump driven by osmotic pressure. Some are biodegradable. Experimental delivery systems have been developed incorporating ear implants and liposomes. The anthelmintic efficacy of some drugs has been potentiated by the synergistic action of metabolic inhibitors and these combinations hold promise for the future. Much new information is now available on those factors which affect anthelmintic efficacy such as concurrent administration with food and the presence of the target parasites themselves. This knowledge provides a sound basis for the rational use of anthelmintic drugs.

Topics: Alginates; Animals; Anthelmintics; Anti-Bacterial Agents; Benzimidazoles; Drug Combinations; Drug Delivery Systems; Helminthiasis; Helminthiasis, Animal; Ivermectin; Liposomes; Macrolides; Morantel; Pharmaceutical Vehicles

Release rates from controlled release devices are determined by the device itself and thus are accurate, reproducible and predictable, whereas in general, prolonged or slow release systems are sensitive to environmental conditions. Diffusion and dissolution are the principal means of achieving controlled release. A diffusion system is specific for the active ingredient and release rate decreases proportionately to the square root of time because of a decreasing concentration gradient or an increasing diffusion path. In dissolution systems, the choice of matrix determines the rate of dissolution and release rates are linearly related to the area of dissolution which can be maintained constant. Consequently, this system has general application, a sharp cut-off point and can be used for more than one ingredient simulatenously. Potential disadvantages of controlled release technology centre on unacceptable tissue residues and parasite resistance to the chemicals used. Advantages include, the ability to programme the release of compounds to achieve specific effects for various periods, decreasing the frequency of dosage and increasing the choice of compounds for the control of parasitic infections. Sufficient epidemiological information should be available before controlled release technology is implemented. Existing anthelmintics and control strategies can be used to achieve an enhanced, but expected result, e.g., prolonged reduction in pasture contamination to protect both ewes and lambs. In future it should be possible to devise compounds and strategies appropriate to the unique features of controlled release technology, e.g., compounds which interrupt or inhibit the growth and development of parasites. Environmental impact should be low because of the specific effect and low dosage of the chemical used.

Topics: Animals; Animals, Domestic; Anthelmintics; Artiodactyla; Benzimidazoles; Delayed-Action Preparations; Drug Interactions; Drug Resistance; Helminthiasis; Helminthiasis, Animal; Morantel; Pharmaceutical Vehicles; Technology, Pharmaceutical

A high, constant and sustained release of drug appears to be a major requirement to avoid a late season rise in pasture infectivity that may result in production losses in calves in autumn or Type II osteragiasis in the following spring. The timing of administration is of crucial importance and will vary in regions of different epidemiology, such as between northern and southern United States. Lack of a standard and reliable technique for pasture larval counts has resulted in some negative or erratic results which are open to question. Although controlled release anthelmintics offer advantages of convenience, a comparison of the economic benefits at present favours prophylactic treatment of dairy heifers with conventional anthelmintics 3 and 6 weeks after spring turnout in northern regions of the Northern Hemisphere. There is a serious risk that boluses based on controlled release by diffusion will behave like slow decaying insecticides and select strongly for drug resistance, especially if farmers administer them in succession throughout the grazing season. There are, however, 2 features in the design of a controlled release device that in theory may minimize the risk of rapid selection for resistance: a high and constant release of anthelmintic followed by a rapid decline to zero as the device becomes exhausted. Under these conditions, the device may even prolong the useful life of an anthelmintic to which resistance has already developed. This paper was presented at Pfizer Symposium on The Application of Sustained Release Anthelmintic Dosage Forms in the Control of Parasites in Grazing Animals at the World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) 10th International Conference, 18-20 August 1983, Perth, W.A., Australia.

Topics: Animals; Anthelmintics; Cattle; Cattle Diseases; Costs and Cost Analysis; Delayed-Action Preparations; Drug Resistance; Feces; Helminthiasis; Helminthiasis, Animal; Ivermectin; Lactones; Morantel; Parasite Egg Count; Poaceae; Pyrimidines; Seasons

Topics: Animals; Anthelmintics; Drug Resistance; Fenbendazole; Gastrointestinal Diseases; Goat Diseases; Goats; Helminthiasis; Helminthiasis, Animal; India; Ivermectin; Levamisole; Morantel; Nematoda; Parasite Egg Count; Sheep; Sheep Diseases

A comparison was made of the efficacy and parasitological sequelae over 2 years, of continuous and intermittent periods of anthelmintic suppression applied both early and in the middle of the first grazing season of calves. Five groups of 15 calves grazing separate paddocks within the same field were allotted to one of the following treatment regimes during their first year at grass: Group 1, untreated controls; Group 2, treated with ivermectin injections at 3, 8 and 13 weeks after turnout; Group 3, treated with ivermectin injections at 10, 15 and 20 weeks after turnout; Group 4, treated with a morantel slow release intraruminal bolus at turnout; Group 5, treated with a morantel slow release bolus at 10 weeks after turnout. Five animals from each group were slaughtered at the end of both grazing seasons. Two months after the end of the second season the remaining five calves were challenged with an experimental infection of 250,000 third-stage larvae (L3) of both Ostertagia ostertagi and Cooperia oncophora. All treatment regimes protected the respective calves from parasitic gastroenteritis. Over the 2 year observation period Groups 2 and 4 showed significantly better weight gain than other groups, and at the end of the first season, they were found to harbour significantly fewer O. ostertagi in the early fourth stage of development. During Year 1, Groups 2 and 3 excreted much lower percentages of Ostertagia spp. eggs than other groups. In Year 2, Group 2 excreted a higher percentage of Ostertagia spp. eggs although the total egg output was approximately half that of Group 1 during the same period. The results showed that the effects of anthelmintic suppression on egg output of different nematode species was affected by the activity of the anthelmintic used.

Topics: Animal Feed; Animals; Cattle; Cattle Diseases; Delayed-Action Preparations; Helminthiasis; Helminthiasis, Animal; Injections; Ivermectin; Morantel; Ostertagiasis; Parasite Egg Count; Pepsinogens; Poaceae; Seasons

The efficacy of using a bolus containing morantel in a sustained-release preparation for controlling naturally acquired gastrointestinal parasitic infections in weaned calves and yearling cattle was investigated during the 1982 grazing season at selected sites in the United States and Canada. According to a common trial design under various climatic and management conditions, 10 field trials were conducted with the bolus. At the time of spring turnout, a bolus was administered to each calf or yearling in the treated group. Then, treated and control cattle grazed separate but equal areas of divided pasture(s). The epidemiologic pattern of parasitic gastroenteritis in control animals and the effect of treatment on this pattern was determined in each trial. Safety and practicality of use of the bolus also were established. When compared with untreated cattle (control), those given the bolus deposited significantly (P less than 0.05) fewer worm eggs (89% reduction) during the first 90 days of the grazing season, as well as significantly fewer (P less than 0.05) worm eggs (84% reduction) during the entire grazing season. Consequently, during the second half of the grazing season, larval populations on treated pastures remained significantly (P less than 0.05) lower (66% reduction), compared with numbers of larvae found on control pastures. For pastures grazed by treated and control cattle at trial initiation, mean worm counts recovered from tracer calves were equal, indicating comparable pasture contamination at the beginning of the grazing season.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Body Weight; Canada; Cattle; Cattle Diseases; Delayed-Action Preparations; Feces; Helminthiasis; Helminthiasis, Animal; Helminths; Intestinal Diseases, Parasitic; Larva; Morantel; Parasite Egg Count; Pyrimidines; United States

Topics: Animals; Anthelmintics; Benzimidazoles; Cestode Infections; Goats; Helminthiasis; Helminthiasis, Animal; Ivermectin; Kinetics; Lactones; Levamisole; Morantel; Nematode Infections; Phenothiazines; Sheep; Sheep Diseases; Thiabendazole; Trematode Infections

A number of anthelmintics are available for the control of gastrointestinal nematodes in cattle. In North America, O. ostertagi, Cooperia spp., lung worm, and F. hepatica probably cause the greatest losses in production. The older anthelmintics are often deficient in their action against some of these parasites. Recently, the Paratect morantel tartrate slow-release bolus has provided a mechanism for the prevention of infections with gastrointestinal nematodes and lung worm, to some extent, and this has been shown to produce considerable economic benefits. Fenbendazole removes arrested O. ostertagi larvae; thus, its availability is an important step in the prevention of type-2 ostertagiasis. It also has a very broad spectrum of activity that includes most other nematodes and tapeworms and is a very safe anthelmintic. Ivermectin is highly effective against almost all cattle nematodes and also has great value for the control of arthropod ectoparasites. In addition, it and levamisole are the only anti-nematode drugs that can be administered to cattle by injection. Clorsulon is a new, safe anthelmintic that provides good control of liver fluke and, thus, fills a gap in the control of helminths of cattle in North America. The efficient use of anthelmintics in association with management based on a knowledge of parasite epidemiology can ensure that cattle do not rapidly become re-infected. In this way, the benefits from the use of anthelmintics can be very considerable and far greater than the costs of control.

Topics: Animals; Anthelmintics; Benzimidazoles; Cattle; Cattle Diseases; Coumaphos; Fenbendazole; Helminthiasis; Helminthiasis, Animal; Ivermectin; Kinetics; Lactones; Levamisole; Morantel; Organophosphorus Compounds; Phenothiazines; Sulfanilamides; Thiabendazole; Umbelliferones

Topics: Amidines; Animals; Anthelmintics; Benzimidazoles; Cats; Cattle; Diethylcarbamazine; Dogs; Helminthiasis; Helminthiasis, Animal; Horses; Ivermectin; Lactones; Levamisole; Morantel; Organophosphorus Compounds; Piperazine; Piperazines; Praziquantel; Pyrantel; Salicylanilides; Sheep; Tetramisole

A field trial involving 217 dairy cows from 13 herds located in four different areas of Quebec was conducted to determine the level of subclinical parasitism. The effect on milk production was evaluated on 116 cows following a single anthelmintic treatment with morantel tartrate administered at freshening. The results showed that this treatment increased milk production in nine herds, which was statistically significant at P 0.05).

Topics: Animals; Cattle; Cattle Diseases; Female; Helminthiasis; Helminthiasis, Animal; Lactation; Morantel; Pregnancy; Pyrimidines

Topics: Animals; Anthelmintics; Bithionol; Cattle; Cattle Diseases; Drug Therapy, Combination; Ethiopia; Helminthiasis, Animal; Intestinal Diseases, Parasitic; Morantel; Niger; Tetramisole; Thiabendazole

Forty heifer calves, 27 yearling heifers, and 64 yearling steers with naturally occurring infections of nematode parasites were treated with levamisole HCl or morantel tartrate or were not treated. Although heifer calves had much larger worm egg counts before treatment than yearling heifers, necropsies showed a smaller average number of nematodes in the calves. Both anthelmintics significantly reduced the egg counts. At the end of the experiments, 98 to 240 days after treatments, there was no significant difference among groups of cattle in respect to necropsy worm counts. An advantage of 5% in rate of gain in body weight was shown in each experiment or phase of an experiment in favor of the treated groups of cattle. Overall, an advantage of 6% in feed efficiency was calculated for the treated groups of cattle.

Topics: Animal Feed; Animals; Anthelmintics; Body Weight; Cattle; Cattle Diseases; Feces; Female; Georgia; Helminthiasis; Helminthiasis, Animal; Levamisole; Male; Morantel; Parasite Egg Count