Cereal grains are the main ingredients of ruminant rations, but their rapid degradation seriously impairs rumen fermentation and the health of the host [
1]. The most part of the digestible energy in cereal grains comes from starch. Starch digestion rate is momentous in attention to the venture of rumen acidosis, as a high rate of starch degradation in the rumen induces a severe fall in ruminal pH, which may diminish microbial protein synthesis, fibre digestion, and feed intake, and, in addition, negatively impact the metabolic condition of the animal [
2]. Cereal starch can be an origin of glucose if a procedure of treating is applied, which decreases rumen degradation, thereby allowing it to be digested in the small intestine [
3]. Therefore, the goals of grain processing include attempts to maximize total starch digestion in the animal, to optimize starch fermentation in the rumen to enhance volatile fatty acids yield while avoiding acidosis, and to advance starch availability in the small intestine [
4,
5]. Various processing methods have recently been applied to enhance the digestibility of barley, each of which requires special circumstances and different effects [
6,
1]. Because the starch digestion of the cereals in the rumen adversely affects the efficiency and health of the animal [
7], so many methods including physical and chemical methods are applied to moderate its rumen disappearance rate [
8,
9]. Alkaline processing has been found to increase the digestibility of ruminant feeds [
10]. This response to alkaline processing is due, in part, to solubilization of hemicellulose, as it is a major portion of the seed coat of most cereal grains [
11]. However, information is still limited as to whether alkaline compounds (AC) can impact the rumen ecosystem when it is applied for barley grain processing. It has been proposed that alfalfa and sugar beet pulp are all nice sources of pectin having high cation exchange capacity (CEC). The CEC is a plant’s ability to attract and bind hydrogen ions [
12]. The CEC evaluates the ionized surface groups of fibre, which may affect the rate of adhesion of microorganisms to the fibre and, thus, the rate of digestion, and may also provide significant buffering capacity in the gastrointestinal tract [
12]. When hydrogen ions are bound to a plant component rather than being free in the rumen, the rumen is less acidic [
13]. High concentrations of free hydrogen ions in the rumen bring high rumen acidity. Hydrogen ions have a positive charge and plant cells usually have many negative charges on their surface and so, bind hydrogen ions. If the ions chemically adjoin the plant rather than being free, the rumen will become minor acidic and, so, feeding this group of grains (cereal) can prevent metabolical disorder in cows [
14]. Thus, the microbes flourish faster and the rate of digestion of the plant cell is increased [
14]. In ruminants, however, it is not obvious if this plant ability may apply to processing of cereal grain in view of starch digestion. In this study, assumed that organic treatment versus chemical manners of treating barley grain may alter the abundance or the metabolic activity of microbes in the rumen, most likely by changing the site and extension of the substrate availability. Therefore, the purpose of these experiments was to measure the effect of various chemical or organic treating on
in vitro first order kinetic parameters of digestion and determining
in situ mobile bag disappearance of the dry matter (DM), crude protein (CP), and starch of barley grain in the rumen, post-rumen, and total tract.