IGF1R and mastitis: Here we demonstrate that cows that are susceptible to mastitis have 13GFEZL and a relatively long stretch of cytosine residues (C stretch) in the 5′ untranslated (5UTR) region of IGF1R. 13GFEZL and the longer C stretch of IGF1R together enhance expression of IGF1R in terms of both messenger RNA (mRNA) and protein levels.