E. Videv, J. Krastanov*, S. Laleva, Т. Angelova, M. Oblakova, N. Oblakov, D. Yordanova, V. Karabashev
Agricultural Institute, 6000 Stara Zagora, Bulgaria
(Manuscript received 24 March 2017; accepted for publication 30 May 2017)
Abstract. Investigation for determining the amount of in vitro gas production after feeding different groups of forages was performed at the Agricultural Institute-Stara Zagora. Forages from different regions were collected and analyzed for in vitro gas production at 24 h and 48 h by Ankom Technology®. The following parameters of the tested forages were determinated: Neutral detergent fibre (NDF, %), Acid detergent fibre (ADF, %), Digestibility of dry matter (DDM, %), Dry matter intakе (DMI, %) and Relative Feed Value (RFV, %). RFV was calculated on the base of DDM and DMI in comparison with alfalfa biomass in flowering stage. Collected feeds (46 samples) were divided in 11 groups on the base of their composition and structure – fibre component content. Depending on the amount of gas production forages can be divided in 3 groups: 1) Grain feeds generating the highest amount of gas – average 387.93 ml/g DM; 2) Combined feeds, fresh forages, complete feed mixtures – average 213.87- 245.15 ml/g DM; 3) Hay, silage, straw, complete feed mixtures + bioadditives – average 115.06 – 208.34 ml/g DM. Intensity of gas production in grain feeds was higher at 24 h, while on the opposite, was higher at 48 h in roughage feeds due to the different speed of degradation of feeds – concentrated had a very intensive and quick degradation, roughages – slow degradation. Supplementation of combined feeds with bioadditives Rumanol, Biolife, Bibor decreased the amount of gas production by 9.87% – 29.05%.