Effect of dietary energy on growth and reproductive characteristics of Angus and Senepol bulls during summer in Florida

Pubertal Angus bulls (n=10, 503 days of age and weighing 366 kg) and Senepol bulls (n=10, 457 days of age and weighing 381 kg) were stratified by age and weight into 2 dietary treatments formulated to provide equal amounts of crude protein and 75% (below) or 150% (above) of the maintenance requirements for metabolizable energy. Measurements to assess body growth and libido were collected at 28-day intervals for 112 days (June through September). Twice during each 28-day interval, the bulls were subjected to breeding soundness examinations. At the end of the experiment, gonadotropin releasing hormone (GnRH) — induced secretion of luteinizing hormone (LH) and testosterone (T) in the serum were determined. At the end of the experiment, bulls fed the above maintenance diet (P