In a pasture environment without a significant supplementation program, Holsten X beef cows do generally poorly. Given average quality forage, they alwasy tend to look poor. Frequently increasing the supplementation just increases milk yield without an improvment in condition. Even with a high degree of supplementation, dairy cows being milked have a poor breed back rate. Those the cheat the bucket will sometimes breed back early, but that is pretty counterproductive.
The standard joke with our vet is how poor of a condition is "too" poor condition. We have one Red Angus cow that milks the weight off and I jokingly refer to her as my red Holstein. During August and September she will shed weight till she's just a rack of bones. But she's bred back by then and carrys her calf. After weaning she'll gain 4-5 lbs a day on just pasture and go into winter in good condition and be fat by next calving season. Holstein X beef cows won't ave a very high value at the sale barn if they come off of pasture. But, if she breeds back, raises a good calf, doesn't break down and goes into calving season in good condition, you might as well keep her around until she fails to produce. The worst part is the amount of feed that she will require all year round to do her job. A smaller cow that doesn;t milk as heavy will in the long run be more economical