Energy balance and net energy for maintenance of beef × dairy crossbred steers

Authors: CANTERBURY, LANDON - Texas Tech University; GALYEAN, MICHAEL - Texas Tech University; DORNBACH, COLTEN - Texas Tech University; CHILDRESS, KALLIE - Texas Tech University; THOMPSON-SMITH, AUBREY - Texas Tech University; SITKA, BLAKE - Texas Tech University; LOEFFLER, TAYLOR - Texas Tech University; GRAND, MADDIE - Texas Tech University; BAKER, MADDY - Texas Tech University; Sanchez, Nicole; Broadway, Paul; HALES, KRISTIN - Texas Tech University

Submitted to: EAAP International Symposium on Energy and Protein Metabolism and Nutrition
Publication Type: Abstract Only
Publication Acceptance Date: 4/5/2025
Publication Date: 9/15/2025
Citation: Canterbury, L.G., Galyean, M.L., Dornbach, C.W., Childress, K.D., Thompson-Smith, A.C., Sitka, B.T., Loeffler, T.A., Grand, M.S., Baker, M.G., Sanchez, N.C., Broadway, P.R., Hales, K.E. 2025. Energy balance and net energy for maintenance of beef × dairy crossbred steers. EAAP International Symposium on Energy and Protein Metabolism and Nutrition.

Interpretive Summary:

Technical Abstract: Our objective was to determine the partitioning of energy in beef × dairy crossbred steers fed at 2 multiples of maintenance and to determine their net energy for maintenance (NEm) requirement. Beef × dairy crossbred cattle make up approximately 28% of the cattle on feed in the United States. Net energy for maintenance and the efficiency of metabolizable energy use is currently unknown in this population. It is hypothesized to be intermediate between beef steers and dairy steers. Beef × dairy steers with Holstein dams and Angus or Angus × Simmental sires were used in a crossover design (n = 17; initial BW = 492 ± 21 kg). Steers were assigned randomly to either maintenance energy intake (1X; estimated at 84 kcal/kg of MBS) or 2-times maintenance energy intake (2X). Total fecal and urine collections were obtained over 6 d along with gas exchange over a 24-h period. After the collection period, steers were fasted, and fasting heat production (FHP) estimates were obtained using indirect respiration calorimeter headboxes (24 h). Body weight and DMI differed (P < 0.01) between treatments. On a megacalorie basis, digestible energy, fecal and urinary energy loss, metabolizable energy, heat production, and recovered energy were greater (P < 0.01) for the 2X steers. Total methane production tended (P = 0.06) to increase for 2X steers. Apparent DM digestibility was less (P = 0.02) in the 1X than in the 2X steers. As a percentage of intake energy (IE), urinary energy loss, metabolizable energy, heat production, and retained energy were greater (P = 0.02) for the 2X than for the 1X steers. Fecal energy loss tended to increase (P = 0.07) for 2X steers, which caused a tendency (P = 0.07) for digestible energy, as a percentage of IE, to decrease for 2X vs. 1X steers. As expected, enteric methane production, as a percentage of IE, was greater (P < 0.01) for 1X steers. Using metabolizable energy intake and recovered energy during FHP, 1X, and 2X measurements the estimate of NEm was 117 kcal/kg BW0.75. This value is greater than native beef cattle and dairy cattle currently reported by NASEM (2016). Steers were outside of thermoneutral for 41% of the study and were younger than the beef and dairy steers evaluated for previous NEm determinations (Blaxter and Wainman, 1966). Both factors could have contributed to an increased NEm value because greater temperature would have changed energy partitioning and younger cattle have increased NEm requirements because of growth. The NEm requirement of beef x dairy steers deserves further research to determine whether this value is repeatable and to directly compare it with purebred beef and dairy cattle in the United States.