Comprehensive assessment of candidate genes associated with fattening performance in Holstein–Friesian bulls

The objective of this study was to determine the association of single nucleotide polymorphisms (SNPs) in selected candidate genes with fattening performance traits in a commercial cattle herd. Fifteen SNPs in 12 candidate genes (LEP, FABP4, DGAT1, TG, IGF1, IGF1R, MYF5, LGB, CAPN1, CAST, GHR, and OLR1) were evaluated in 296 purebred Holstein–Friesian bulls using PCR-RFLP (polymerase chain reaction – restriction fragment length polymorphism). Associations between each segregating SNP and genetic merit for fattening performance were quantified using linear mixed models. Traits included in the study were fattening period, final weight, dry matter intake, feed conversion rate, and average daily weight gain. Apart from the general determination of the above-mentioned traits, each trait was evaluated based on the fattening periods between five selected target body weights (W1 [Formula: see text] 100 kg, W2 [Formula: see text] 200 kg, W3 [Formula: see text] 300 kg, W4 [Formula: see text] 400 kg, W5 [Formula: see text] 450 kg). All markers with the exception of CAPN1 530, IGF1R, TG, and DGAT1 were associated with at least one of the traits. Furthermore, novel associations were observed for LEP [Formula: see text] GHR, IGF1 [Formula: see text] LEP, FABP4 3691 [Formula: see text] FABP4 2834, and FAP4 3533 [Formula: see text] LEP interactions. The results of this study confirm some previously reported associations. Moreover, novel associations have been identified, which may be incorporated into breeding programs to improve fattening performance.