Phenotypic and genetic correlations between feeding behaviours and feed efficiency in crossbred beef replacement females
Olson, C.A., Li, C., Block, H., McKeown, L., Basarab, J.A. (2020). Phenotypic and genetic correlations between feeding behaviours and feed efficiency in crossbred beef replacement females. Canadian Journal of Animal Science, [online] 100(4), 781-785. http://dx.doi.org/10.1139/CJAS-2019-0212
Plain language summary
Feeding behaviour, dry matter intake, and feed efficiency are important traits of beef cows as they are related to animal welfare or production efficiency. However, reports on genetic parameters including heritability and genetic correlations of the traits in beef cows are limited. In this study, dry matter intake (DMI), feeding duration (DUR), feeding frequency (FREQ), head down time (HD), and time-to-bunk (TTB) were collected on 1394 crossbred replacement heifers using the GrowSafe automated feed bunk systems. Feed efficiency was measured as residual feed intake adjusted for off-test ultrasound back fat thickness (RFIFAT). The data were used to estimate genetic parameters for the traits. Heritability estimates for DUR, HD, FREQ, TTB, DMI, and RFIFAT were 0.25, 0.26, 0.27, 0.29, 0.26, and 0.40, respectively, which was from low to moderately high. Genetic correlations of the feeding behaviour traits with DMI and RFIFAT were general y low. However, moderately high genetic correlation (r=0.41) between DUR and DMI was observed (0.41), indicating that selection for reduced DMI could affect feeding duration. These genetic parameters will help design a better selection program that optimizes performance of feeding behaviour, dry matter intake, and feed efficiency in beef cattle.
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 (RFIFAT) were also reported. The h2 estimates for DUR, HD, FREQ, TTB, DMI, and RFIFAT 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.