If you're looking at nucleosome positioning you probably need ATAC-seq data and/or DNAse -seq data etc. ChIP-seq won't give you that unless you are looking at a specific nucleosome remodeling protein (or any protein for that matter). Also specifying from what bovine tissue you want would be most helpful. People generally don't sequence nucleic acids from the whole eukaryotic organism.
You can download most SRA files from published data if authors of a specific paper have made it available. If you read this post here on biostar it is pretty detailed about how to go about doing that.
Best wishes, Val