JOURNAL OF ANIMAL SCIENCE

Mazandaran, Iranin the diets of lactating dairy cattle. The first two are the nature of the NDF and the nature of non-fiber carbohy-drates (NFC), and the third component is one of the fol-lowing: NDF content, NFC content, or NDF:NFC ratio [1-3]. Carbohydrates consisting of NDF and NFC frac-tions make up 65%–75 % of rations. However, issues have whereas NFC content ranges from 45 % to 35 % [3,4]. The NFC has been represented as a single value for feeds or diets, but the type of carbohydrates in this frac-tion largely varies. For example, the NFC in corn grain is mostly starch (65%–70 % of DM), beet and citrus pulp provides sugar (12%–40 % of DM) and neutral detergent-soluble carbohydrate (NDSC) (25%–44 % of DM), and sugar (mono- and oligosaccharides) predominates in molasses [5]. In addition, some of the variation in the re-sults of the effect of the type and amount of NFC o