Effect of Dietary Hempseed Meal on Growth Performance, Feed Efficiency and Blood Parameters in Yearling Rough Stock Bulls

Abstract

Yearling rough-stock bulls (n = 38) were utilized in a randomized complete block design to evaluate dietary hempseed meal (HSM) inclusion on growth (ADG), intake (DMI), and efficiency (F:G). Bulls were blocked by body weight (BW), grouped into 10 pens (n = 3–4 bulls/pen), and randomly assigned to an HSM or control supplement treatment (CON; 72.5% cottonseed meal, 14.5% soy hulls, 13% fat). Treatments were offered at 10%, while 90% was fed as a mixed ration [50% Bermuda grass hay, 40% textured commercial feed (10% CP)]. Diet samples were dried and DMI was calculated. F:G was evaluated using DMI and ADG. Blood for plasma analysis and BW were obtained on sample days, prior to feed delivery. Data were analyzed using the GLIMMIX procedure in SAS version 9.4. The results were considered significant when p ≤ 0.050. There was no treatment × time interaction, or treatment effect for interim BW, ADG, or F:G (p ≥ 0.100). A treatment × time interaction occurred for DMI (p < 0.01), and BW (p = 0.01) increased in all bulls over time, while ADG decreased (p = 0.005), suggesting that interim live performance was not affected by HSM. Plasma urea nitrogen increased over time (p < 0.001) in all bulls, with greater concentrations observed in HSM bulls (p = 0.043).