As cows are turned onto pastures this spring, be alert for a drop in milk solids, says Virginia Isler, a dairy specialist with Pennsylvania State University.
“When pasture is lush, cows can be consuming a lot of dry matter from this source,” she says. “Rate of passage can be extremely high, and the result is inadequate fiber and energy…. There is [also] an energy expense to the cow when pastures contain extremely high protein levels.”
So if grazing is a significant portion of the feed cows consume, consider strategies to slow the rate of feed passage through the rumen and increase energy density. “Checking body condition score and bulk tank components can serve as a guide on when to make changes,” Isler says.
And as summer progresses, pasture quality can deteriorate—particularly if there is reduced rainfall. Then, cows might not be consuming enough dry matter.
“If these scenarios continue for any length of time, body condition can start deteriorating, which can negatively affect milk production and components,” she says.
Limiting time on pasture and feeding stored commodities may be required to avoid reduced performance. In today’s economy, maintaining at least 5 ½ pounds of combined milkfat and protein sold per cow per day is necessary to remain competitive, she says.