Evaluation of a new long-acting oxytetracycline formulation against anaplasmosis in colombian cattle.

A long-acting injectable (Terramycin/LA) forulated to contain 200 mg/ml of oxytetracycline was tested and compared to a commercially available oxytetracycline injectable (Emicina) containing 50 mg/ml in the treatments of experimentally induced Anaplasma marginale infection in Colombian cattle. Group 1, consisting of 10 infected calves, served as non-treated controls. Ten infected calves (Group 2) were treated with two doses of Emicina, each at 10 mg/kg, intramuscularly (IM), and another ten infected calves (Group 3) were treated once IM, with 20 mg/kg of Terramycin/LA. All treatments were given during the acute phase of infection after A. marginale parasitemia was demonstrated and when the packed cell volume (PCV) had decreased to 60-64% of normal value. Two treatments with Emicina and one with Terramycin/LA were both effective in moderating the course of A. marginale infection and in preventing serious clinical signs of disease under laboratory conditions.