Generally you have to do a little more than "offer"... :lol: I fed a dairy bull calf his first bottle this afternoon and he threw a huge fit. Didn't want me near him, didn't want his mouth open, didn't want the bottle in - but then he did want the milk! Drained the bottle.
I'd supplement her with a bottle, so you know how much milk she's getting (sometimes those cows can have huge bags, but it's mostly just swelling, no milk), and then pen up the cow and calf for a day or two to keep an eye on them and make sure the calf nurses. Also, if it were mine, I'd give a Bo-Se shot and Vitamin B complex shot. If your area isn't deficent in selenium it wouldn't be a problem, but our area certainly is and most of my calves get a Bo-Se shot. The Vitamin B seems to give them an appetite and generally perks them up - I've given that to several calves that "just didn't act quite right". (However, it's worth noting that they also had some other problem I was/would be treating them for - ie scours or pnemonia.)