Evaluation of Ruminal Dry Matter Disappearance and pH of Dry Corn, High-Moisture Corn, and Rye under <i>in Vitro</i> Conditions

Abstract

An in vitro experiment was conducted to evaluate the effects of grain type on in vitro dry matter disappearance (IVDMD) and pH using ruminal fluid and a buffer reagent. Five beef cows were used for ruminal fluid collection and ruminal fluid was pooled prior to use. The cows used for ruminal fluid collection were maintained on a forage-based diet (60:40 forage to concentrate) for 28 d prior to ruminal fluid collection. Three grain types were evaluated: 1) dry corn (89% dry matter; DRC), 2) high-moisture corn (72% dry matter; HMC) and 3) rye (89% dry matter; RYE). Data were analyzed as a completely randomized design. A total of twenty-one replications of each grain type were used for statistical analysis (n = 63 tubes total). IVDMD was greater ( P ≤ 0.05) by 97.1% and 46.4% for RYE compared to DRC and HMC, respectively. Additionally, IVDMD was greater ( P = 0.05) by 34.6% for HMC compared to DRC. Final pH was decreased ( P ≤ 0.05) for RYE by 12.3% and 2.8% for RYE compared to DRC and HMC, respectively. Also, final pH was decreased ( P = 0.05) by 9.8% for HMC compared to DRC. These data indicate that corn harvest method (dry vs. high-moisture) influences IVDMD and final pH and that rye has a greater disappearance of dry matter and lower final pH than corn under in vitro conditions.