University of Minnesota M.S. thesis. April 2019. Major: Animal Sciences. Advisor: Alfredo DiCostanzo. 1 computer file (PDF); vii, 44 pages.A series of three 10-d experiments using a Latin Square design, was performed to determine whether hay processing and feeding method (Exp. 1), energy supplement moisture content and feeding method (Exp. 2) or access time to hay (Exp. 3) by late-gestating beef cows affected hay or supplement DMI and waste. In Exp. 1, large round bales were processed with a bale buster, to an average theoretical length of 12 cm, and delivered on the pen surface or in a bunk or left unprocessed and delivered in a hay ring or rolled out on the pen surface. In Exp. 2, corn screenings (CS) or wet beet pulp (BP) was fed in a structure (inverted tire or feed bunk) or on the pen surface (BP only). In Exp. 3, cows were permitted access to large round-bale hay in a hay ring for either 6, 14 or 24 h. In Exp. 1, hay DMI was not (P > 0.05) affected by hay processing or feeding method, and averaged 11.6 kg/d. Hay waste was greater (P = 0.0003) for cows fed hay on the pen surface (19.1%). In Exp. 2, hay DMI was greatest (P < 0.05) for cows fed no energy supplement and those fed CS in a bunk. Cows fed BP in a bunk wasted the most (P < 0.0001) hay (18.1%). In Exp. 3, DMI and waste was greatest (P < 0.0001) when cows had access to hay for 24 h. Cows allowed 6-h access to hay consumed and wasted less (P < 0.0001) hay compared to those given 14-h or 24-h access. In these experiments, cows fed hay on the pen surface achieved similar DMI as those fed in a structure, but wasted more hay. Delivering a high-moisture supple¬ment on the pen surface or bunk increased supplement or hay waste. Controlling access to hay reduced DMI and waste while maintaining cow BW
