The aim of this study was to investigate the effects of a treatment with the antibiotic tiamulin (Denagard®, Novartis Animal Health Inc., DE) on the occurrence of different bacterial lung pathogens and clinical signs of a respiratory disease in growing pigs in a field trial.
The study included 150 pigs at 9 weeks of age, which were randomly divided into a treatment group (TIA) and a control group (KONT). The pigs of the TIA-group received 15 mg / kg / day tiamulin (tiamulin hydrogen fumarate, Denagard® 45 % oral, Novartis Animal Health Inc., DE) through the drinking water over 14 days, while the KONT-group was left untreated. Out of every group, 30 pigs served as sampling animals to acquire brochoalveolar lavage fluid (BALF). The BALF was collected on study day 0, 14 and 21. The BALF samples were used for further bacteriological investigation and a PCR was conducted for the detection of Mycoplasma (M.) hyorhinis and M. hyopneumoniae. A clinical investigation was done on those 60 sampling animals on day 0, 14 and 21, which included the specific parameters: body condition, auscultation of the lung, colour of nose and skin and swelling of tarsal joints. The results were listed using a specific scoring system (PALZER et al., 2007b). Additionally on study day 1, 2, 3, 5, 7, 9, 11, 13, 14, 15, 17, 19 and 21, a cough index was calculated for both groups including all animals in the pens. All pigs were weighed individually on study day 0, 14 and 21.
The results showed a significant reduction of the amount of Haemophilus (H.) parasuis, M. hyorhinis and α-hemolytic Streptococci in the TIA-group. A significant reduction could also be seen for H. parasuis in the KONT-group. The amount of Pasteurella (P.) multocida and Bordetella (B.) bronchiseptica isolated, did not differ significantly between the three sampling days in both groups. Actinobacillus (A.) pleuropneumoniae could only be isolated from the BALF of six animals at the beginning (day 0) of the study. β-hemolytic Streptococci could only be isolated sporadically. The cough index measured, showed an estimated decrease of 50% within 6.1 days in the TIA-group, while in the KONT-group a decrease of 50% could not be obtained during the study period of 21 days. The clinical score of the KONT-group showed a significant increase over the study period, leading to a significant lower clinical score in the treated animals on day 14. The average weight gain of the TIA-group was significantly higher than in the KONT-group during the trial period. In the present study, a significant reduction of different lung pathogens could be seen in the group of pigs treated with Tiamulin. In addition the treatment with tiamulin led to a significant improvement of clinical behaviour and performance of the pigs.