688. Candidate genomic regions for forage dry matter intake in Swedish dairy cows using single-step genome-wide association

The study was conducted to identify genomic regions associated with forage dry matter intake (DMIFor) in Swedish Red (SR) and Holstein (SH) cows using single-step genome-wide association methods. Phenotypic data were from 1,177 lactations of 356 SR and 219 SH cows, of which 255 were genotyped. A mixed linear animal model was fitted. The gene annotation revealed 84 variants associated with DMIFor, 76 of which were found for parity2+ in SH. The genomic variants were annotated and generated 33 candidate genes associated with DMIFor only in SH. The candidate genes that include MAPK10, SOX6, TCF7L2, CREB5, INPP4A, ATP13A3, SND1 and IRS1 were detected associated with DMIFor. The study revealed 10 QTL regions in 9 chromosomes. Our findings offer new insights into the genetic basis of DMIFor and provide a guide to breeding cows producing milk on forage.