Enables UDP-galactose:beta-N-acetylglucosamine beta-1,3-galactosyltransferase activity. Acts upstream of or within glycosaminoglycan biosynthetic process. Located in Golgi medial cisterna. Human ortholog(s) of this gene implicated in Ehlers-Danlos syndrome spondylodysplastic type 2 and spondyloepimetaphyseal dysplasia with joint laxity type 1. Orthologous to human B3GALT6 (beta-1,3-galactosyltransferase 6). [provided by Alliance of Genome Resources, Apr 2022]