Ligori Viviane Andrade, Malheiros Jessica Moraes, Carrara Eula Regina, Dominguez-Castaño Pablo, da Silva Neto João Barbosa, Dos Santos Gonçalves Cyrillo Joslaine Noely, Mercadante Maria Eugênia Zerlotti, Zadra Lenira El Faro
School of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal, SP, Brazil.
Animal Science Institute, Beef Cattle Research Center, Sertãozinho, SP, Brazil.
J Appl Genet. 2025 Mar 17. doi: 10.1007/s13353-025-00959-3.
The Caracu is a taurine breed adapted to Brazil's climatic conditions and has been selected for 40 + years for Body Weight (BW), maintaining performance records across multiple generations in its database. However, selecting young animals for BW can result in excessive growth, potentially impacting carcass and reproductive traits. This study aimed to estimate genetic correlations and, based on these estimates, evaluate how selection for BW (adjusted to 378 and 550 days of age for males and females, respectively) has influenced carcass traits and reproductive efficiency in this breed. The dataset contained records for BW (kg), Ribeye area (REA, cm), Height-to-width ratio of the Longissimus dorsi muscle (HWR), Backfat thickness (BFT, mm), Rump fat thickness (RFT, mm), Yearly scrotal circumference (SC, cm), and Days to calving (DC, days) from animals born between 1966 and 2022. (Co)variance components were estimated by Bayesian inference using two-trait animal models. Analyses were conducted to estimate genetic parameters for pairs of traits, including BW with carcass traits (BW × REA, BW × HWR, BW × BFT, and BW × RFT) and BW with reproductive traits (BW × DC and BW × SC). Additionally, analyses were performed for pairwise combinations among carcass traits (REA × HWR, REA × BFT, REA × RFT, HWR × BFT, HWR × RFT, and RFT × BFT) and between reproductive traits (DC × SC). The relationship matrix included 4,783 animals, of which 829 were genotyped with the GGP Bovine 100 K SNP panel. Favorable genetic correlations (r) were observed between BW and REA (0.51 ± 0.11), HWR (0.45 ± 0.17), SC (0.24 ± 0.13), and RFT (0.15 ± 0.21), with the latter being favorable but low. On the other hand, unfavorable genetic correlations were observed between BW and BFT (-0.07 ± 0.21), which was unfavorable but close to zero relationship, and between BW and DC (0.48 ± 0.15). The significance of carcass and reproductive traits is underscored by the favorable, r between BW and the carcass traits REA (BW × REA) and HWR (BW × HWR), while a high, unfavorable r was observed between BW and DC cows. These findings emphasize the importance of carefully balancing genetic selection to optimize growth, carcass quality, and adequate reproduction in Caracu cattle.
卡拉库牛是一个适应巴西气候条件的瘤牛品种，在其数据库中已针对体重（BW）进行了40多年的选育，保持了多代的性能记录。然而，选择体重较大的幼畜可能会导致过度生长，潜在地影响胴体和繁殖性状。本研究旨在估计遗传相关性，并基于这些估计值，评估针对体重（分别针对雄性和雌性调整至378日龄和550日龄）的选择如何影响该品种的胴体性状和繁殖效率。数据集包含1966年至2022年间出生动物的体重（kg）、眼肌面积（REA，cm）、背最长肌高宽比（HWR）、背膘厚度（BFT，mm）、臀脂厚度（RFT，mm）、年阴囊周长（SC，cm）和产犊天数（DC，天）的记录。通过使用双性状动物模型的贝叶斯推断估计（协）方差成分。进行分析以估计性状对的遗传参数，包括体重与胴体性状（BW×REA、BW×HWR、BW×BFT和BW×RFT）以及体重与繁殖性状（BW×DC和BW×SC）。此外，还对胴体性状之间（REA×HWR、REA×BFT、REA×RFT、HWR×BFT、HWR×RFT和RFT×BFT）以及繁殖性状之间（DC×SC）的成对组合进行了分析。关系矩阵包括4783头动物，其中829头用GGP牛100K SNP芯片进行了基因分型。在体重与眼肌面积（0.51±0.11）、背最长肌高宽比（0.45±0.17）、阴囊周长（0.24±0.13）和臀脂厚度（0.15±0.21）之间观察到有利的遗传相关性，后者虽有利但较低。另一方面，在体重与背膘厚度之间观察到不利的遗传相关性（-0.07±0.21），虽不利但接近零相关，在体重与产犊天数之间观察到不利的遗传相关性（0.48±0.15）。体重与胴体性状眼肌面积（BW×REA）和背最长肌高宽比（BW×HWR）之间的有利遗传相关性强调了胴体和繁殖性状的重要性，而在体重与母牛产犊天数之间观察到较高的不利遗传相关性。这些发现强调了仔细平衡遗传选择以优化卡拉库牛生长、胴体质量和适当繁殖的重要性。
