hmmm....as a rule, Holsteins are pretty mellow. However, between 1-2 years of age plenty of cows start testing the waters. You have to remind them who is boss. I have Holstein heifer that's about the same age as yours. We loaned her to a friend to keep his single cow company when he brought his others over here for breeding with our bull. While she was there, she learned some bad habits....butting up against people for scratches and treats....so we are re-training her to give us space and respect people.
We've often found too that cycling cows that are not bred often tend to be a little more unpredictable than a cow that is pregnant. Usually these cows settle right down once they are bred.
So basically she saw the last cow act up and jump fences so she coping this...?
About 2 weeks or so ago I loaded and took away a cow that was jumping fences and crushing them. I keep them rotating theses fields like musical chairs repairing old delapidataed fences . I feed them everyday to keep them happy. They in good shape , but fields need improvement and besides cuttin and rollin Hay which I know good enough I know nothingDid I miss something?