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Simple Summary: Industrial hemp by-products have yet to be approved by the organizations governing what can be considered an animal feed ingredient, highlighting the importance of determining the safety and efficacy of hempseed meal as a potential feed ingredient for ruminants. In this study, hempseed meal, a by-product of hemp oil production, was offered to yearling rough-stock bulls at 10% of the diet. No effects on weight, interim intake, or efficiency were observed, suggesting that the overall performance of animals offered the hempseed meal versus a control supplement was not different. Bulls offered the hempseed meal supplement were also observed to maintain an elevated dry matter intake per day compared to bulls offered the control supplement. Furthermore, elevated plasma urea nitrogen concentrations were observed in the bulls offered the hempseed meal. Bulls offered the hempseed meal performed similarly to those fed the same nutrient profile of standard, commercially available feed ingredients, indicating comparable nutrient availability. This demonstrates the potential of hempseed meal to effectively compete against readily available feed ingredients. 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). [ABSTRACT FROM AUTHOR]

The Association of American Feed Control Officials (AAFCO) is gathering information about the safety and efficacy of hemp and its derivatives as potential animal feedstuffs. Yearling rough-stock bulls (n = 38) were used in a randomized complete block design to evaluate the effects of hempseed meal (HSM) as a concentrate ingredient on growth, dry matter intake (DMI), and efficiency. Bulls were blocked by body weight (BW), grouped into 10 pens (n = 3 or 4 bulls/pen), and randomly assigned to hempseed meal (HSM) or a control supplement treatment (CON; 72.5% cottonseed meal, 14.5% soy hulls, and 13% fat). Ingredients for CON were used because they were common commercial commodities and were formulated to match the macronutrients of HSM. Treatments were top-dressed at 10% of the diet, while 90% was fed as a mixed ration [50% bermudagrass hay, 40% textured commercial feed (10% CP)]. Feed delivery, treatment delivery, and orts were recorded daily. Diet samples were dried and used to calculate dry matter intake (DMI). Blood for urea-N (SUN; VetScan Chemistry Analyzer) and BW were obtained on days 0, 21, 42, and 63. Efficiency was evaluated for each period using DMI and average daily gain (ADG). Data were analyzed using the GLIMMIX procedure in SAS 9.4. Results were considered significant at P < 0.05, and tendencies were discussed at 0.05 > P > 0.10. No treatment×time interaction occurred for BW (P = 0.999), ADG (P = 0.563), interim DMI (P = 0.672), feed efficiency (P = 0.254), or SUN (P = 0.170). Treatment did not affect BW (320.4 and 324.69 ± 121.57 kg for CON and HSM, respectively, P = 0.996), but BW increased over time (261.13 ± 74.71 and 322.5 ± 121.57 kg, initial and final BW, respectively, P = 0.001). No treatment effect on ADG occurred (0.73 and 0.84 ± 0.13 kg for CON and HSM, respectively, P = 0.680). However, ADG decreased over time (1.0 ± 0.29, 1.19 ± 0.21 and 0.79 ± 0.13 kg, d0-21, d21-42, and d42-63, respectively, P = 0.005). Daily DMI resulted in a treatment×time interaction, where HSM often consumed more DM than CON (P < 0.01). Interim DMI increased over time (7.44 ± 1.25, 7.84 ± 0.98, and 8.18 ± 0.82 kg, d0-21, d21-42, and d42-63, respectively, P = 0.0073), but when combined with ADG to determine feed efficiency, the main effects were not different (P = 0.17). Over time, SUN increased (4.91, 10.52, 11.66 and 12.72 ± 0.35 mg/dL for days 0, 21, 42 and 63, respectively, P < 0.001), and HSM had greater SUN than CON (10.46 and 9.45 ± 0.30 mg/dL for HSM and CON, respectively, P = 0.0426). These data suggest that bulls fed HSM at 10% diet DM perform similarly to bulls fed the same nutrient profile of standard commercial feed ingredients, indicating comparable nutrient availability between the treatments. Conversely, increased DMI and SUN in the HSM bulls suggest a difference in nitrogen metabolism between the treatments that warrants further investigation. [ABSTRACT FROM AUTHOR]