I agree with that. We like to keep them in good shape all the time. Not over fat, but in good shape. It's cold enough here that it means hay in front of them all the time, except right now, when they're grazing corn.
Yours will be in the last trimester soon, and that's when the calf grows the most, and they need their groceries to make sure the calves are strong, and if they're in good shape then, rebreeding will be easier.
I'm not sure by weights if it's enough, but if the cows are in good shape, then it is. If they're losing weight, I'd bump it up.