Have had alot of dairy cross animals over the years. They make good nurse cows, will raise nice enough calves as they do milk quite a bit. Sometimes the "dairyness" comes out in the calves and it will hurt them at the sale barn, but a 3/4 beef calf will usually do okay. Yes, they do tend to fall off weight some if you run them just with the beef cows and since you didn't list where you are, the winters can take a little more out of them. Their udders will sometimes "fall" as they get some age on them. Still, I have several, and will keep any I can get. If you have the place to do it, they will often take an orphan calf, and a couple of mine have been seen in the field with 2 calves on them so they sometimes let other calves steal off of them.
Do you have other beef cows? The way prices are you may not be getting a bargain, but you didn't say how much they wanted. She will never get as big as a beef cow but will usually raise more pounds for her size than you would expect since she will make more milk.
If she has heifers, she will put more milk back into them and they will raise nice calves bred beef, as they will have a little more milk for their calves. We have about 4 that are 3/4 angus and 1/4 holstein in the herd and they milk like crazy and their calves look all beef.
