Phenotypic and genetic analysis of auction selling performances of young Simmental calves

Italian Simmental (IS) is a dual-purpose cattle breed that counts about 90,000 cows registered in its official Herdbook. The breeding scheme is based on a composite index in which meat production has a 20% weight. The sale of calves is a source of revenue for farmers; thus, the Italian Simmental Breeders Association is planning to include data coming from auctions in its breeding scheme. The aim of this study was to analyse phenotypic and genetic background of age at auction (AU), live body weight (LBW), price per kg of body weight (PKg) and total sale price (TSP) recorded during auctions. Records were available for 51,825 Simmental calves coming from 2180 herds and sold during 898 auctions in the period 2004–2023. The traits were analysed using herd, sex, age of the dam as cross-classified fixed effects; for the genetic analysis, animal and maternal genetic effects were included. All considered effects had a significant impact on the analysed traits. Heritability estimates were 0.16 ± 0.01, 0.35 ± 0.02, 0.24 ± 0.02 and 0.27 ± 0.02, for AU, LBW, PKg and TSP, respectively. The high phenotypic correlation found between LBW and TSP confirmed the weight as the main variable responsible for the selling price. The results corroborated the negative genetic correlations between AU and weight or TSP. The analysed traits were almost not correlated with the other traits already included in the breeding program. The efficacy of these traits for predicting future performances of calves at the end of the cycle of fattening should be further investigated.