[Comparative trial of drug premixes for preventing dysentery in growing pigs]

Four experiments (three under conditions existing in the practice), each one comprising four groups of pigs equalized in weight from 8 to 35 kg were carried out. All groups received the same ration, but no medicamentous premix was added to the ration of the control group, while the experimental groups were for checking the following premixes: MRz containing ridzol, MPr containing prozhen and MAv containing avimertonid. The mean daily and fodder expenditure were recorded in the course of the experiment. It was established that the experimental groups to the ration of which was added medicamentous premix had 3.4 to 20% higher mean daily gain (P < 0.05), and a 0.428-0.521 kg lower mean fodder expenditure per 1 kg gain (10%). Regular application of medicamentous premixes to the ration of 12 929 pigs in the swine complex of Blagoevgrad and of 44 254 pigs in the swine complex of Harmanli shaprly decreased the sick rate of bacterial, vibrionic and protozoa enterites, growing pig mortality was reduced by 35-50%, and the prime cost of 100 kg gain was lowered by 6-7 Leva. It became evident that it is more feasible to apply a premix containing ridzol during the first period of growth (up to 20 kg body weight) and a prozhen premix during the second period of growth (from 20 to 35 kg).