Evaluation of the zootechnical and economic effectiveness of using the Kluver Pro+ supplement in feeding replacement heifers

The article presents the results of a comprehensive study on the use of the Kluver Pro+ feed supplement based on live Kluyveromyces marxianus milk yeast in the rations of Holstein replacement heifers. The aim of the work is to assess the zootechnical and economic efficiency of probiotics used in feeding dairy and transitional growing animals. A six-month scientific and economic experiment has been conducted on three groups of heifers, 14 heads each. In addition to the basic ration in the control group, 4 and 8 g / head / day of Kluver Pro+ supplement have been additionally fed to heifers in Groups 1 and 2. It has been found that the addition of the yeast probiotics in the rations of growing animals has improved the digestibility of feed mixtures, significantly increased the digestibility coefficients of dry and organic matter, crude protein and crude fiber, the number of rumen ciliates, and prevented the colonization of the rumen by pathogenic bacteria. The absolute live weight gain during the experiment has averaged 141.5 kg for the control group, while in experimental groups 1 and 2, it has been 151.0 and 158.9 kg, respectively, with an increase of 6.7 and 12.3%. The experiment has revealed that the supplement under study has increased the average daily weight gain of breeding heifers from 786 to 839 and 882 g, respectively, and improved the animals’ conformation parameters, including oblique body length, height at the withers, and chest width and depth. Based on the analysis of zootechnical and economic parameters, the Kluver Pro+ dosage of 8 g/head/day should be considered as the most effective one, achieving the highest live weight gain and increasing the production profitability to 15.6%.