In vitro and in vivo evaluation of the effects of a compound based on plants, yeast and trace elements on the ruminal function of dairy cows | Evaluation in vitro et in vivo d'un composé à base de plantes, levures et oligo-élements sur la fonction ruménale des vaches laitières.

anglais. peer reviewed

anglais. High production levels reached by the dairy sector need adjustment in nutritional inputs and effi-cient feed conversion. In this context, we evaluated a compound (QY-Qualix Yellow) combining optimized inputs in trace elements and 20% MIX 3.0. In a first step, the effects of MIX 3.0 on ru-minal function were assessed in vitro by incubating ruminal fluid with the mixture at a ratio 20:1. The results obtained encouraged us to test QY in vivo, on a herd of dairy cows. The herd was di-vided into one group of 19 dairy cows receiving the compound and a control group of 20 animals conducted in the same conditions but which have not received it: the production performance and feed efficiency of the 2 groups were compared. In vitro experiments showed improved diges-tion of acid and neutral detergent fibers by 10%. The propionate production was enhanced by 14.5% after 6 h incubation with MIX 3.0. The plant mixture decreased the production of methane and ammonia by 37% and 52% respectively and reduced by 50% the number of protozoa. An in-crease in milk yield by 2.4 kg/cow/d (p < 0.1) combined with a decrease in concentrate consump-tion of 0.27 kg DM/cow/d (p < 0.001) was observed in vivo after consumption of the compound. After 66 days since the beginning of the trial, methane emissions per kg of milk were significantly lower in the group receiving QY. In conclusion, MIX 3.0 induced change in ruminal function in vitro and when it entered into the composition of the QY, it appeared to improve feed efficiency and production performance in vivo.