Incidence de facteurs alimentaires sur l'obtention de resultats faux positifs lors de la detection des antibiotiques dans le lait par la methode Delvotest SP.

The study described in this paper was performed to show the influence of feed complemented by minerals, oligo-elements and vitamins (CMV) on the results of Delvotest SP®. Three trials were developed. In the first trial, a group of 13 dairy cows was divided into two subgroups of six and seven cows, receiving the first one a feed basis without CMV, the second one, the same feed basis added of 100 g CMV per day. During the second trial, the dose of CMV was doubled for the last seven cows. During the third trial, all the 8 cows were grazing. The four cows of the test group received 200 g of CMV per day. The two homogeneous groups of cows (somatic cells, number of lactations) were followed for detection of inhibitors in milk using Delvotest SP®. The test gave positive results with milk from complemented cows during the first and the second trials. All results were negative during the third trial. Feed appears to be a factor that may give false positive results in the determination of antibiotics in milk with Delvotest SP®.