EN
For breeders of racing horses, preventing diarrhea episodes and reduction of diarrhea severity in foals is still a big challenge in the production of top performers. The objective of the study was to assess the effect of heat treated L. farciminis, L. rhamnosus, L. plantarum and Propionibacterium sp. (VivaFlor Optimax) in Thoroughbred mare’s diet during late gestation and early lactation on foals’ diarrhea episodes and severity. Fourteen mares randomly chosen out of 27 mares were placed on a diet supplemented with VivaFlor Optimax in the course of 3 months at 5 g, containing at least 1 × 10⁹ of dead microbial cells/g of formulation, every evening. The remaining 13 (out of 27) mares made up the control group. The number of diarrhea days, the medicine treatment, appearance and behavior of the foals were recorded every day. VivaFlora Optimax reduced the severity and duration of the foals’ diarrhea. The foals of supplemented mares suffered 3 times fewer diarrhea days as compared to the control group. The reduction was statistically significant (Anova test p < 0.05). Moreover, in contrast to the control group, the foals from the supplemented group did not require external treatments in order to fully recover.