How to bring the reference genome to Usegalaxy

How to bring the reference genome bovine to Usegalaxy for use in GATK, Variant Recalibrator
there are not “bovine” reference genome in Variant Recalibrator.
I bring refseq with UCSC but i think sth is wrong and Variant Recalibrator done with error!
I did it in UCSC as below:
UCSC/genome:Cow/select the assembly then group:Mapping and Sequencing, Track Assembly/ last output format:= “sequence” and get output to Galaxy

Look at “Custom builds” under the User menu

Thanks, can you tell me how i can use this option in usegalaxy?