Holstein feeder sales are fairly common in areas with alot of dairies. They don't sell on BCS system.....although they are graded on flesh/condition and frame size.....they are sold at all weights... most are in the 350 lb range and up... weaned and on feed. It depends on the area and the farmer... but many are put on feed by former/retired dairy farmers, Because they were good at growing holstein heifers, and since they no longer milk, they are good at feeding holstein steers.....some feed up to 1,000 lbs and then they go on feedlots.
So, anyone that raises some bottle calves will get them weaned and started on feed. Grain and hay and some grass... Holsteins eat alot and have to have a good protein to grow body & bone.... so many people will sell them by the time they reach 4-500 lbs . Most holsteins are weaned off bottles by 8-12 weeks...
Many are sold in the weaned 4-5 wt range...
The buyers know what they are looking for... there are farmers that specialize in feeding out holsteins. There are buyers for all sizes. One of my dairies feeds his to the 8-900 lb range... another that likes to ship them off at 550 or 600.
Used to be a farmer would raise his holstein bull calves up, make them steers, then sell once a year to pay taxes or have extra money at Christmas. Value added when he had the extra feed already there to feed..... Some would sell in the 4-6 wt range in the spring when it was greening up for grass...
For years we would get $.50/lb average for most any weight holstein.. with the cost of milk replacer being low, or raising them on a nurse cow, even with feeding grain, you could make a little money on them. Then the bottom fell out, baby calves were giveaways... and the milk replacer costs jumped but the return did not. Wasn't hardly worth the time...
Now with baby calves ... holstein, black or whatever, bringing in the $750-1500 range... holstein feeders are a gamble but are bringing decent money. However, most of my dairy farmers are selling them at 3 day old size, because at 500 lbs and bringing $3.00 lb... there is not much return for all those months work. Black ones... holstein/black beef crosses are in the high end prices... if you lose one or 2 you have buried a real significant amount of money.
But if you can get some of the smaller (60-75 lb ) holstein bull calves for lesser money, there is a return selling them as feeders. Many will grow out decently, they just need a little more time to catch up to their 100 lb "brothers.