Postmodern management of starchy grains for ruminants: A barley grain perspective

Abstract

Maintaining optimal rumen conditions faces many challenges when feeding ruminants barley grain (BG). This is because >90% of BG endosperm can be rapidly degraded to acids, peptides, and ammonia, whereas corn grain is degraded more slowly and only by 35–50%. Excessive processing may reduce and maintain rumen pH under 5.8, causing prolonged subacute rumen acidosis (SARA) and suppressed immunity. Steam-rolling and grinding are two main global processing methods for BG. It is criticized how inaccurately inherited focus on processing rather than accurate dietary inclusion rate of BG has compromised rumen and ruminant health. Overemphasis on processing methods and quality control have kept producers far from granting deserving thoughts into safe BG inclusion rates under different feeding programs. A major philosophy for steam processing of hard grains (e.g., corn and sorghum) is to increase rumen starch and protein fermentation extent, whereas in softer grains (e.g., BG) a primary goal is totally different, being instead to control and decelerate fermentation shortly post-feeding. These aims must be profoundly appreciated to maximize microbial mass yield and overall VFA production with minimized risks from SARA and immune dysfunction. Optimum dietary inclusion rates and physical form of BG in relation to physiological stage and lactation performance are discussed. In practice, challenges usually arise from too-complex outlooks. Main challenges faced by ruminant industries will not be to alleviate or attenuate disorders such as SARA and pro-inflammatory reactions, but instead to prevent and minimize their occurrence. A perturbing trend in modern ruminant industries has been creating health problems by improper feeding strategies and investing time and other resources to overcome such problems. Optimum processing techniques and feeding strategies of BG should aim to minimize metabolic complexities, and improve economics by more effective prognosis, diagnosis, and treatment. Effectual ruminant management is in controlled microbial cereal starch utilization in the rumen. Rumen is a foremost target to improve starch and BG assimilation in postmodern ruminants.