Technical Abstract: In a previous study, a normalized cDNA library was developed from pooled mammary gland tissues and sequenced. Expressed sequence tags were assembled into tentative consensus (TC) sequences and compared by BLAST to the gene indices of other species and the human genome assembly. Those TCs identified as unique to the Bos taurus gene index and with no assignment to the Eukaryotic Gene Orthologs (EGO) database were selected for additional sequencing. Clones (n = 69) comprising the 3' end of each TC were sequenced and incorporated into new TC assemblies. These data will be used to characterize previously unidentified transcripts and identify those which may represent genes unique to ruminants.