Nutritive Value Variation and In Vitro Digestibility of Hempseed Meal.

Abstract

Simple SummaryWhile there have been international studies on hemp as a livestock feed source, information is limited in the U.S.A. Hempseed meal, the byproduct of oil production, is relatively unexplored. Our research focused on determining variability among hemp seed meal sources and batches within sources, through chemical analysis and in vitro digestibility of samples. Our research found nutritive value variability among batches, but not sources, of hempseed meal. In vitro digestibility only slightly decreased when hempseed meal was included at increasing percentages as a protein replacement in the ration. These data indicate that hempseed meal may be an effective source of crude protein for inclusion in ruminant livestock rations. Hempseed meal (HSM) is left after oil extraction of hemp and may act as a protein source in livestock. The first phase of this research evaluated variation in nutritive value and in vitro dry matter digestibility (IVDMD) of HSM from various sources in North America; the second phase utilized IVDMD to evaluate the efficacy of hempseed meal as an ingredient in ruminant feed. In phase one, the source had no contribution to variance for neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), or crude protein (CP) (p ≥ 0.20). However, batch within source contributed to variation for NDF (50%), ADF (37%), ADL (13%), and CP (31%; p ≤ 0.01). Irrespective of differences in nutritive value, there was no contribution to variation (p = 0.23) of any measured response on in vitro true digestibility (53.0%). In phase two, two experiments evaluated HSM IVDMD as (1) a concentrate replacement or (2) a protein replacement in rations at varying rates. In the first experiment, IVDMD decreased (p < 0.05) with increasing levels of HSM. In the second experiment, IVDMD decreased (p < 0.01) as HSM inclusion increased. Although IVDMD decreased as HSM inclusion increased, values still met the digestibility threshold for ruminant rations, indicating that HSM has potential as an alternative protein ingredient.