Whole Milk vs. Milk Replacer for Calves
Today I was asked about feeding whole milk to calves rather than milk replacer.
Here is the situation. The owner buys cheap bull calves at a sale barn. He has been feeding milk replacer. Last week a nearby dairy offered him waste milk free - just come get it. His question was essentially, "Would feeding whole milk be better for the calves than milk replacer [he was feeding 20-20]?"
I explained that as an energy source waste milk at roughly 4.0 percent fat is substantially higher in energy than his 20-20 milk replacer. In fact the waste milk is likely 50 percent higher in energy!
However, on the downside, waste milk can be quite variable in both composition and dry matter. That is, dry matter on just the one farm could easily vary from 11 to 15 percent solids. This fluctuation can encourage scours in calves compared to a fixed dry matter percentage. How much of a risk? Probably low but present.
Protein and fat levels can go up and down, too. This may be less of an issue given these levels are higher than the milk replacer he is presently feeding.
I recommended that on several different days he get samples of the milk that is being offered. Freeze them and get them to a lab to be cultured for bacteria. Coming out of the cows the bacteria levels are likely to be acceptable for feeding calves. But, depending on post-collection handling, waste milk bacteria counts often approach 1,000,000 cfu/ml - very, very high and unacceptable for feeding calves.
I have to admit that I did not get information from him about the bacteria counts of the "as-fed" milk replacer on his operation. I hope this was not too great an omission.