Objective: We assessed the quality of the disinfection Prophylactic of formaldehyde at 2 % with a temperature of 70 ° C in a not faulty cattle installation. Materials and Methods: After mechanical cleaning, the disinfectant solution was applied by a mobile unit and after three hours of exposition, it was carried out the sampling by means of swapped of floors, walls, troughs and drinking troughs, being proceeded later on to the inoculation in parallel of three means of cultivations: Modified Heifetz (MH), modified Heifetz with histidine 0.1% (MHH) and at Lactose bromothymol blue broth (LBBB) for coli forms. Results and Conclusion: Lapsed the period of incubation, the results were evaluated statistically by means of the test of comparison of proportions. Under the conditions of the experiment bigger effectiveness was verified in terms of delectability of the LBBB, with differences statistically significant (p < 0.05) regarding the MH (41.0 vs. 17.9%). The differences among the comparisons LBBB vs. MHH (41.0 vs. 30.8%) and MH vs. MHH (17.9 vs. 30.8%) were not significant.
