Beef cattle

Assessment of genetic parameters and trends for growth, carcass, reproductive, feed-efficiency, and methane-emission traits in an experimental beef cattle population over four decades of selection

---

Abstract

Long-term assessment of selection strategies is essential to capture their cumulative effects, verify the maintenance of genetic gain, and detect correlated responses that may not be apparent in the early stages of a breeding program. The Nellore experimental breeding program at the Institute of Animal Science (Brazil) was established in 1980 with three closed lines of Nellore cattle selected for postweaning weight (WSEL) and residual feed intake (RFI). The main objectives of this study were to: (i) estimate heritability (h²) and genetic correlations (rg) for growth, carcass, reproductive, feed efficiency, and methane emission traits; and (ii) assess genetic trends for these traits over more than four decades of selection. The database included 13,360 animals in the pedigree file born from 1958 (founders) to 2024, of which 3,860 were genotyped and imputed to a high-density SNP panel (383,507 SNPs). The traits evaluated were birth weight (BW), body weight adjusted to 210 days of age (W210), WSEL, RFI, postweaning average daily gain (ADG), postweaning residual ADG (RADG), hip height (HH), heart girth (HG), ribeye area (REA), backfat thickness (BFT), rump fat thickness (RFT), days to calving (DC), scrotal circumference (SC), dry matter intake (DMI), feed conversion ratio (FCR), and methane emission (CH₄). Genetic parameters were estimated using AIREML method based on a ssGBLUP approach. Genetic trends were estimated by linear regressions of the mean GEBV for each birth year from 1981 to 2024. The highest h2 were observed for HH (0.49±0.02), SC (0.48±0.03), and BW (0.44±0.02), followed by WSEL (0.34±0.02), RFT, and DMI (both 0.33±0.03), HG and REA (both 0.31±0.02), CH₄ (0.30±0.06), BFT (0.29±0.02), and ADG (0.26±0.03). Lower h2 were obtained for RFI (0.19±0.03), W210 and RADG (both 0.13±0.03), FCR (0.12±0.03), and DC (0.09±0.01). WSEL was strongly genetically associated with W210 (0.92±0.02), HG (0.84±0.02), HH (0.73±0.02), ADG (0.71±0.05), DMI (0.70±0.05), BW (0.53±0.04), REA (0.50±0.05), and CH₄ (0.50±0.15). Low to moderate rg were found between WSEL with RADG (0.29±0.11), FCR (-0.27±0.11), SC (0.20±0.05), BFT (0.17±0.06), RFT (0.15±0.06), DC (0.02±0.07), and RFI (0.01±0.09). Genetic trends of GEBVs from the two selected lines (without the control line) were higher for WSEL (1.33 kg/year), W210 (0.66 kg/year), CH4 (0.57 g/day/year), HG (0.21 cm/year), HH (0.17 cm/year), REA (0.12 cm2/year), BW (0.11 kg/year) and SC (0.03 cm/year). Smaller but positive trends were observed for DMI (0.03 kg/year), RFT (0.01 mm/year), and BFT (0.01 mm/year), whereas ADG, RADG, and RFI were very close to zero. DC (−0.18 days/year) and FCR (-0.01) showed negative and favorable genetic trends. These results demonstrate that long-term selection for postweaning weight in Nellore cattle can sustain genetic progress in growth and body size, while revealing correlated responses in feed efficiency, reproduction, and methane output, thereby providing important guidance for beef cattle breeding programs.

Keywords: 2026

How to Cite:

Mercadante, M., Rodrigues, G., Valente, J., Silva, J., Soares, T., Feitosa, F., Pinto, K., Brito, L., Canesin, R., Bonilha, S. & Cyrillo, J., (2026) “Assessment of genetic parameters and trends for growth, carcass, reproductive, feed-efficiency, and methane-emission traits in an experimental beef cattle population over four decades of selection”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2286428. doi: https://doi.org/10.31274/wcgalp.24001

Rights: 1