A pound of milk doesn’t buy as much feed these days. The milk-feed price ratio — the government’s benchmark of producer profitability — fell to just 1.83 in May. The more the ratio drops below the target of 3.0, the less feed you can buy per pound of milk sold.

Whether you track the milk-feed ratio or income over feed cost, profit margins are tight. Your feed dollar can only stretch so far. Keep it from losing more elasticity by honing in on metabolizable or “true” protein. You’ll lower dietary protein, spend less on feed cost, but maintain milk production. 

Better quality protein 

The concept of using metabolizable protein in ration balancing is not new, but it makes a whole lot of sense during times of high feed cost.

The idea is to feed the cow more closely to her protein needs. When you do that, the rumen works more efficiently at synthesizing its own protein. The benefit of that is two-fold. You get more metabolizable or “true” protein — the type that’s absorbed in the small intestine and converted into amino acids, and you feed less dietary crude protein.

A couple years ago, the Penn State University dairy farm reduced crude protein from 18 percent to 16 percent in the lactating-cow ration. This improved amino-acid profiles in the metabolizable protein generated by the cows. This is what you want because amino acids, and not protein, are what cows require to make milk, explains Gabriella Varga, dairy nutritionist at Penn State University.

Amino-acid profiles are difficult to measure on-farm, but the concept of using metabolizable protein in ration balancing still makes sense because it’s a better source of protein for the cow. On farm, the value of that is evident in other ways.

Lower MUN

About a year ago, Chuck Hempfling of Delphos, Ohio, started feeding less crude protein to his lactating cows. Dietary crude protein in the ration dropped from 18 percent to 15 percent. In nearby Haviland, Ohio, Jaap Van Erk did the same thing. He cut crude protein from 17.6 percent to 16.5 percent.

“What we’re doing is optimizing protein utilization,” says John Wenning, dairy nutritionist with Land O’ Lakes Purina Feed and nutritionist for both herds.

One of the first side benefits that both herds noticed was a reduction in milk urea nitrogen levels.

In Hempfling’s herd, MUN readings fell from 12 to 14 milligrams per deciliter to 10 or 11 mg per dL. The lower MUN level means he’s not wasting money on excess dietary protein, and neither is Van Erk. His 650-cow herd’s bulk tank MUN score is usually around 11 mg per dL — down from 15 mg per dL a year ago.

Both producers stopped wasting crude protein and ended up with diets that more closely matched the cows’ needs. It was a smart decision then — and even more so this year with the price of soybean meal at least $125 per ton higher than a year ago.

Both producers say that lower MUN levels also have improved pregnancy rates. 

No production loss

With less crude protein in the diet, you might expect milk production to decline. Not so. Both Hempfling and Van Erk achieve consistent — if not better — milk production. Feed intakes also have stayed consistent in both herds.

In Van Erk’s herd, production is at 75 pounds per cow per day. The fresh group achieves 95 pounds per cow per day. This is consistent with the milk production he saw prior to initiating a metabolizable-protein program. Sure, he’d like to see it higher, but Van Erk is still pleased because he’s getting the same amount of milk on less dietary protein.

Hempfling’s 188-cow herd saw a production jump of 6 to 7 pounds per cow per day when he started on the Land O’ Lakes metabolizable-protein system last year. He has since gone off rbST, which cut into production. Now, production is usually a consistent 70 pounds per cow per day.

Research studies also show no loss in production when crude protein levels drop. In fact, it’s often optimized at lower levels. Research conducted a few years ago at the U.S. Dairy Forage Research Center in Madison, Wis., shows that milk production is greatest when dietary crude protein is 16.5 percent as opposed to higher levels. Cows fed 16.5-percent crude protein achieved a peak milk yield of 84.3 pounds compared to 80.5 pounds and 81.4 pounds per day at 17.9 percent and 19.4 percent crude protein, respectively.

Current market conditions have driven up feed cost per hundredweight of milk. These Ohio producers have used metabolizable protein to their advantage. Try it. It just might make your feed dollar stretch further, too.

More on metabolizable protein

Read a paper on metabolizable protein, presented at the 2007 Penn State Dairy Cattle Nutrition Workshop. Go to: www.dairyherd.com/nutrition.