Genetic association between different criteria to define sexual precocious heifers with growth, carcass, reproductive and feed efficiency indicator traits in Nellore cattle using genomic information

Abstract

The aim of this study was to estimate genetic parameters for different precocious calving criteria and their relationship with reproductive, growth, carcass and feed efficiency in Nellore cattle using the single‐step genomic BLUP. The reproductive traits used were probability of precocious calving (PPC) at 24 (PPC24), 26 (PPC26), 28 (PPC28) and 30 (PPC30) months of age, stayability (STAY) and scrotal circumference at 455 days of age (SC455). Growth traits such as weights at 240 (W240) and 455 (W455) days of age and adult weight (AW) were used. Rib eye area (REA), subcutaneous fat thickness (SFT), rump fat thickness (RFT) and residual feed intake (RFI) were included in the analyses. The estimation of genetic parameters was performed using a bi‐trait threshold model including genomic information in a single‐step approach. Heritability for PPC traits was moderate to high (0.29–0.56) with highest estimates for PPC24 (0.56) and PPC26 (0.50). Genetic correlation estimates between PPC and STAY weakened as a function of calving age. Correlation with SC455, growth and carcass traits were low (0.25–0.31; −0.22 to 0.04; −0.09 to 0.18, respectively), the same occurs with RFI (−0.09 to 0.08), this suggests independence between female sexual precocity and feed efficiency traits. The results of this study encourage the use of PPC traits in Nellore cattle because the selection for such trait would not have a negative impact on reproductive, growth, carcass and feed efficiency indicator traits. Stayability for sexual precocious heifers (PPC24 and PPC26) must be redefined to avoid incorrectly phenotype assignment.

Genomic evaluation for novel stayability traits in Nellore cattle

“…These estimates are greater than those reported by Silva et al (), who presented heritability estimates of STAY63 in Nellore cattle ranging from 0.03 to 0.07. In contrast, the results of the present study corroborate with Teixeira et al () and Bonamy et al () who reported heritability for STAY63 of 0.14 and 0.16, respectively. Valente et al () evaluating Nellore cows' ability to calve at least three times before reaching 65 months of age, obtained similar results for STAY53, including a heritability estimate equal to 0.13.…”

“…who presented heritability estimates of STAY63 in Nellore cattle ranging from 0.03 to 0.07. In contrast, the results of the present study corroborate withTeixeira et al (2017) andBonamy et al (2018) who reported heritability for STAY63 of 0.14 and 0.16, respectively. Prediction accuracy (r) of estimated breeding values (EBVs), genomic EBVs (GEBVs) and bias obtained through the BLUP and ssGBLUP methods for four stayability traits, and the percentage of increase in prediction accuracy (>Acc) obtained by the ssGBLUP method, in Nellore cattle…”

Genome‐wide association study and pathway analysis for fat deposition traits in nellore cattle raised in pasture–based systems

“…Similar results were reported by Bonamy et al. (2019) with heritabilities of 0.21 and 0.34 for BFT and RFT, respectively, which confirms the selective potential of these traits. The genetic correlation estimates between BFT and RFT were 0.68 ± 0.04, similar to the values reported in other studies with Nellore cattle, as in Buzanskas et al.…”

“…Regarding the heritabilities, estimates of 0.26 for BFT and 0.30 for RFT are of moderate magnitude, indicating a good potential for selection response. Similar results were reported by Bonamy et al (2019) with heritabilities of 0.21 and 0.34 for BFT and RFT, respectively, which confirms the selective potential of these traits. The genetic correlation estimates between BFT and RFT were 0.68 ± 0.04, similar to the values reported in other studies with Nellore cattle, as in Buzanskas et al (2017), Ceacero et al (2016) and Kluska et al (2018), who obtained correlation values between BFT and RFT of 0.59 ± 0.07, 0.79 ± 0.05 and 0.73 ± 0.03, respectively.…”

“…(2015) reported means of 2.77 ± 1.59 mm and 3.77 ± 2.84 mm for BFT and RTF, respectively, and Bonamy et al. (2019) presented means of 3.68 ± 1.75 mm and 4.61 ± 2.44 mm for the same traits. Regarding the heritabilities, estimates of 0.26 for BFT and 0.30 for RFT are of moderate magnitude, indicating a good potential for selection response.…”