Effect of direct-fed microbials plus enzyme supplementation on the fattening performance of Holstein young bulls at two different initial body weights

The study was designated to determine the effects of direct-fed microbials (DFM) plus enzyme supplement and initial body weights on the finishing performance, feed intake and feed efficiency ratio characteristics of Holstein Friesian young bulls. Eighteen male Holstein Friesian from two weight groups [light body weight (LBW) group = 178.3 kg and heavy body weight (HBW) group = 278.3 kg] were fed concentrate and roughages (dry hay and corn silage) for 182 days. DFM plus enzyme-treated animals were fed concentrate supplemented with 20 g of the combination of Lactobacillus acidophilus, L. casei, L. plantarum, Bacillus subtilis, B. licheniformis, Aspergillus oryzae, Enterococcus faecium, as well as enzymes (amylase, protease, cellulose, lipase, pectinase). Although average daily and total weight gains, final weight and DMI from all feeds of the bulls in the DFM plus enzyme group were numerically greater than these of cattle in control group, the differences were not statistically significant. However, supplementing diets with DFM plus enzyme significantly (P<0.01) improved feed efficiency ratio of the young bulls. While total and daily weight gains of the bulls in LBW group were significantly (P<0.01) higher than these of cattle in HBW, DMI from concentrate, roughage and all feeds (P<0.05) of HBW group was greater than these of LBW group. Improvement in the feed efficiency of the bulls in LBW was significant (P<0.01). There were significant (P<0.01) interactions of weight groups and DFM plus enzyme for weight gains and feed efficiency ratio.