Efficacy, safety, and residue evaluation of levamisole gel formulation in sows.

Anthelmintic efficacy, safety, and residue studies were conducted in sows and gilts with a levamisole gel containing 11.5% levamisole HCl. In 12 sows and 12 gilts, 8 mg of levamisole HCl equivalent/kg of body weight orally was 100% (resinate) and 91.1% (gel) effective against 55-day-old Ascaris suum and 100% (gel) and 96.1% (resinate) effective against Oesophagostomum dentatum. In 20 sows given levamisole gel (8 mg of levamisole HCl/kg) orally just before breeding, 4 to 6 weeks after breeding, 4 to 6 weeks before farrowing, and just before farrowing, there were no adverse effects. Transient salivation was noticed in five sows after treatment. In 4 groups of 4 sows each given levamisole gel orally to provide 8, 24, 40, or 80 mg of levamisole HCl/kg, adverse clinical signs were not observed in sows treated with 8 mg/kg. Transient salivation was noticed in one sow given 24 mg/kg, two sows given 40 mg/kg, and four sows given 80 mg/kg. Multiple emesis and chomping occurred in one sow given 80 mg/kg. Levamisole residues in edible tissues from sows given 8 mg of levamisole gel/kg orally were less than 0.1 mg/kg of muscle and fat in sows killed on posttreatment day (PTD) 3 and less than 0.1 mg/kg of kidney in sows killed on PTD 5. Liver residues averaged 0.78 mg/kg in sows killed on PTD 3 and were reduced to 0.31 mg/kg in sows killed on PTD 5. The 99% upper tolerance limit with 95% confidence on the withdrawal time to assure levamisole residues of less than 0.10 mg/kg in liver tissue was 11 days.

Comparative efficacy of sulfamethazine and sulfathiazole in feed for control of Bordetella bronchiseptica infection in swine.

Seventy-two conventionally raised pigs were challenge exposed intranasally when approximately 3.5 weeks old with yolk-grown Bordetella bronchiseptica. Twenty-four pigs acted as noninfected, nonmedicated controls. Feed containing sulfamethazine or sulfathiazole (110 mg/kg of feed) was initiated in 2 groups of 24 infected pigs each 3 days after challenge exposure and was fed continuously for 56 days. Twenty-four infected pigs were given nonmedicated feed. Challenge exposure with the B bronchiseptica resulted in nasal bordetellosis characterized by isolations of the test organism from nasal cavities of infected control pigs at greater than 90% frequency through 28 days and from at least 50% of the pigs through 56 days. Moderate turbinate atrophy developed with a 48% increase in mean turbinate space in infected control pigs at necropsy. Performance was not affected by the infection which was confined to the nasal cavity. The B bronchiseptica isolation rate decreased faster (P less than 0.01) in the sulfamethazine group than in the sulfathiazole group. By day 42, sulfamethazine-medicated pigs were negative for B bronchiseptica in nasal swab samples; whereas 8% to 17% of sulfathiazole-medicated pigs were positive from days 42 to 56. Turbinate spacing measurements averaged 11% less in the sulfamethazine group than in the sulfathiazole group.

Anthelmintic efficacy, safety, and residue evaluation of levamisole gel formulation in cattle.

Anthelmintic efficacy, safety, and residue studies were conducted in beef calves using a levamisole gel formulation. The effectiveness of levamisole gel and tablet formulations was studied in 30 calves with experimental infection of Ostertagia ostertagi. Removal of 33- to 34-day-old O ostertagi was 99.6% and 97.7%, for the gel and tablet formulation, respectively, when administered orally to supply 8 mg of levamisole HCl equivalent/kg of body weight. A comparative blood concentration study was also used to demonstrate bioequivalence of the levamisole gel to the tablet formulation. In a cross-over-designed test, 5 cattle/treatment group were dosed orally with levamisole 11.5% gel or levamisole tablets at the dosage rate of 8 mg of levamisole HCl/kg. Blood levamisole values were similar with the levamisole gel and tablet formulations. In a safety study, 3 groups of 6 calves each were given levamisole gel orally to provide 8, 24, or 40 mg of levamisole HCl/kg. A 4th group served as controls. Adverse clinical signs were not observed in cattle treated with the recommended dosage level of 8 mg/kg. Transient salivation was noticed in 1 placebo control calf, 2 calves given 24 mg/kg, and 4 calves given 40 mg/kg. Edible tissues from cattle given a single oral dose of levamisole gel (8 mg/kg) were analyzed for drug residues 2 hours and 2, 3, 5, and 7 days after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)