The objectives of this study were to identify the phenotypic and genetic relationships and heritability (h²) of feeding behaviours (FB) in replacement beef females. Between 2005 and 2017, heifers (N = 1394) were tested for feed intake using an electronic feed bunk system. The various FB were feeding duration (DUR; min d⁻¹), head down time (HD; min d⁻¹), feeding frequency (FREQ; events d⁻¹), time-to-bunk (TTB; min). Dry matter intake (DMI; kg d⁻¹), and residual feed intake adjusted for off-test ultrasound back fat thickness (RFI_FAT) were also reported. The h² estimates for DUR, HD, FREQ, TTB, DMI, and RFI_FAT were 0.25 ± 0.05, 0.26 ± 0.06, 0.27 ± 0.05, 0.29 ± 0.06, 0.26 ± 0.05, and 0.40 ± 0.07, respectively. These are the first h² to be presented for these FB among developing replacement heifers on a high-forage diet.