Studies on the use of a long-acting oxytetracycline in turkeys: serum levels and tissue residues following injection.

Forty 6-week-old large white commercial turkeys were injected subcutaneously with a long-acting oxytetracycline formulation (69 mg/lb). The turkeys were divided into four groups of 10 birds each, and the birds in each group were bled twice at different times between 4 and 144 hours postinjection (PI) to determine serum levels of oxytetracycline. Two additional groups of turkeys were also given the long-acting oxytetracycline formulation mixed with either neomycin or a bacterin for Pasteurella multocida to determine if either of these compounds interfered with absorption of the oxytetracycline. Serum levels of oxytetracycline were 5.38 micrograms/ml, 1.59 microgram/ml, and 0.93 microgram/ml at 24, 48, and 72 hours PI, respectively, following an average dose of 69 mg/lb of body weight. These levels are all considered therapeutic. There appeared to be no interference with absorption of oxytetracycline when mixed with either neomycin or the bacterin. Tissue residues of oxytetracycline in the muscle, liver, and kidney were within tolerance levels by 3 weeks PI.

Studies on the use of a long-acting oxytetracycline in turkeys: efficacy against experimental infections with Alcaligenes faecalis and Pasteurella multocida.

A group of 2-week-old turkey poults was inoculated with a pathogenic strain of Alcaligenes faecalis. One week later, half the group was injected with a long-acting oxytetracycline formulation. Poults were examined post-mortem on days 3, 5, and 10 post-treatment. Swabs were taken of the trachea, sinus, and lung of each poult. Poults were observed closely for clinical signs, and appropriate tissues were taken for histopathology. Results showed no evidence of therapeutic effect on A. faecalis infection in vivo, even though the organism was highly sensitive in vitro. Six-week-old turkeys were inoculated intramuscularly with 3.7 X 10(3) organisms of the P-1059 strain of Pasteurella multocida. Immediately following inoculation, half the group was treated with the long-acting oxytetracycline. Ninety percent of the untreated poults were dead 72 hours postinoculation, whereas none of the treated turkeys died. No evidence of any clinical disease was observed in the treated group during the 8-day observation period. The long-acting oxytetracycline product was highly efficacious in preventing disease caused by experimental inoculation with the P-1059 strain of P. multocida.