How much feed need a cow per day?

The rule of thumb for the amount of protein beef cattle need is as follows:

• The 7-9-11 Rule: Seven percent protein for mid-gestating cows, 9 percent protein for late-gestation cows, 11 percent protein for lactating post-calving cows.
• The 14-12-10 Rule: 14 percent protein for feeder calves weighing 550 to 800 lbs, 12 percent protein for feeder calves weighing 800 to 1050 lbs, and 10 percent protein for feeders weighing 1050 lbs to finish weight. Similar can be said for young cattle (heifers and bulls) being raised as replacements.

For dairy cows, it gets more complicated, as we have to factor in digestable intake protein [DIP] (also known as rumen degradable protein or RDP) and undigestable intake protein [UIP] (also known as rumen undegradable protein or RUP, or by-pass protein) along with crude protein content of a ration, or rather, divide crude protein into RDP and RUP. Typically, though, we should expect to feed around 10 to 12 percent protein in the form of RDP to dairy cows.