Influence of hempseed cake inclusion on growth performance, carcass characteristics, feeding behavior, and blood parameters in finishing heifers

Authors: WINDERS, T - North Dakota State University; Serum, Eric; Smith, David; NEVILLE, B - North Dakota State University; MIA, G - North Dakota State University; AMAT, S - North Dakota State University; DAHLEN, C - North Dakota State University; SWANSON, K - North Dakota State University

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/26/2022
Publication Date: 5/3/2022
Citation: Winders, T.M., Serum, E.M., Smith, D.J., Neville, B.W., Mia, G.K., Amat, S., Dahlen, C.R., Swanson, K.C. 2022. Influence of hempseed cake inclusion on growth performance, carcass characteristics, feeding behavior, and blood parameters in finishing heifers. Journal of Animal Science. 100:1-8. https://doi.org/10.1093/jas/skac159.
DOI: https://doi.org/10.1093/jas/skac159

Interpretive Summary: Industrial hemp is grown commercially for its fiber and its seeds are used for extracting hempseed oil. Oils pressed from industrial hemp seeds typically contain low concentrations of cannabinoids as does the pressed hempseed residue (hempseed cake). Hempseed cake, a nutrient-rich by-product of oil extraction, has a well-documented historical precedence for use as an alternative feed source for cattle. In recent times, however, very few studies have evaluated the usefulness of hempseed cake when incorporated into a modern feedlot ration. To this end, a study was conducted that compared the performance of feedlot heifers fed rations containing 20% dietary hempseed cake or 20% distillers dried grains plus solubles for a 16-week feeding period. Although cattle fed hempseed cake had slightly poorer growth performance measures than cattle fed distiller dried grains with solubles -likely due to a higher fiber content- performance of hempseed cake-fed heifers was considered acceptable and carcass measures did not differ from the control animals. The study demonstrated that hempseed cake supports growth of feedlot heifers, and could be an economically valuable feed source if competitively priced with other common by-product feeds.

Technical Abstract: As hemp continues to be grown in the US, there is interest in feeding byproducts of industrial hemp production to livestock. An experiment using crossbred finishing heifers (n = 31; initial BW= 494 kg, SE = 10) was conducted to determine the effects of feeding hempseed cake in a corn-based finishing diet (10% forage) formulated to meet or exceed ruminally degradable and metabolizable protein requirements on growth performance, carcass characteristics, feeding behavior, and plasma metabolites. Dietary treatments were inclusion of 20% (dry-matter basis): 1.) dried distillers grains plus solubles (DDGS, n = 16), or 2.) hempseed cake (HEMP , n = 15). Cattle were housed in two pens, had ad-libitum access to feed and water, and individual intakes and feeding behaviors were captured using the Insentec BV feeding system. Cattle were fed treatment diets for 111 to 119 days, body weights (BW) were measured, and blood samples were collected every 14 days. Final BW, average daily gain (ADG), feed conversion (G:F) and hot carcass weight (HCW) decreased (P = 0.05) by 2.3%, 7.7%, 7.7%, and 2.6% respectively in heifers fed the HEMP diet than in heifers fed the DDGS diet. Estimated dietary net energy for maintenance (NEm) and gain (NEg; Mcal/kg of feed, DM basis) were greater (P = 0.02) in diets for heifers fed the DDGS diet than in diets for heifers fed the HEMP diet. All other performance and carcass characteristics were similar (P = 0.20) between treatments. Blood plasma was analyzed for glucose, urea nitrogen, and individual amino acids. Plasma urea nitrogen was greater (P < 0.01) in heifers fed the HEMP diet than in heifers fed the DDGS diet, while glucose was not influenced (P = 0.17) by dietary treatment. Total amino acids, non-essential amino acids, and essential amino acid plasma concentrations were not different between treatments (P = 0.09), while several amino acids were influenced by treatment but not in a consistent manner. There were several observed interactions between treatment and day for individual amino acids. These data suggest that hempseed cake has a lower NEm and NEg relative to DDGS when adequate MP is supplied, while still providing adequate nutrition to support acceptable performance of finishing cattle.