Randy Shaver, a University of Wisconsin Extension dairy specialist, conducted in-depth surveys of 15 these herds since 2004. These herds typically have a tank average of 95 to 100 lb/cow/day. And he has recently analyzed rations of several herds that are reaching 120 lb of milk or more per cow on some of groups.
A summary of all these rations shows that 60 lb of milk is coming from the nutrients in the high-quality forages that are being fed, and just 33 to 40 lb is coming from the grain and concentrate ration components.
Broken down another way, 45% of the crude protein of the diets comes from forage, along with 40% of the starch and 55% of the non-fiber carbohydrates, and 50% of the energy if the diets are heavy in highly digestible corn silage. The forage in these diets also provides 75% of the neutral detergent fiber (NDF) and 85% of the physically effective NDF.
In these herds, every ton of forage dry matter is producing about 3,000 lb of milk, Shaver estimates.
All of the herds were feeding some combination of alfalfa haylage and corn silage, and 11 of the 15 were feeding some dry hay as well. Crude protein on the alfalfa haylage ranged from 17 to 26%, NDF from 34 to 47% and In Vitro NDF Digestibility (IVNDFD)at 30 hours from 39 to 59%. The corn silage starch ranged from 25 to 41% and IVNDFD from 60 to 67%.
The highest herd, with milk production surpassing 40,000 lb of milk per cow, was getting about 84 lb. of milk from forage out of tank average of 140 lb/cow. That, too, is about 60% of the milk production coming from forage.
The alfalfa haylage in this herd tested at 24.5% crude protein, 36% neutral detergent fiber and 52% IVNDFD. The corn silage, however, is where the herd really stands out. It was a BMR variety that was high chopped, at 30” to 36”, to maximize fiber digestibility and starch. It had 35% NDF, 60% IVNDFD and had 41% starch.
“The thing I take away from this analysis is that a lot of farmers and others think we have to feed a lot of grain to get high levels of milk production. This analysis show that that is really not the case,” says Shaver.
The key is high quality forage—both alfalfa and corn silage—that is harvested, stored and preserved to optimize fiber digestibility. “The high herd really shows the potential of maximum production, at least at this point, from forage,” says.
Source: Dairy Herd
Link: http://www.dairyherd.com/magazine/forage-quality-drives-milk-production