Bunk management isn’t just ‘bunk’!
How quickly would you adopt a practice that improves milk and component yields plus feed efficiency — without costing any money? “In a snap,” you say?
Then don’t overlook the mundane task of managing the feed bunk. While often overlooked, it’s where money’s to be made! It ensures your cows are actually taking in the balanced diet they’re receiving.
• There’s “milk money” to be made in better feed bunk management.
• In-day and day-to-day intake variations erode rumen efficiency.
• Top-producing cows are often the best at sorting out the “goodies.”
I constantly preach about high forage diets and maximizing forage intake. Along with high forage diets comes maintaining a consistent forage-to-concentrate ratio of delivered feed.
Day-to-day variations in that ratio affect the rate of volatile fatty acid production in the rumen. That, in turn, affects rumen pH. And that, in turn, affects rumen bacteria species and population.
When populations and species change, rumen digestion also changes. The name of your rumen digestibility game is consistency!
‘Sorting’ disrupts your game
Cows “nose” through feed for the goodies. But this sorting alters your forage-to-concentrate ratio.
When they’re allowed to sort, and that ratio varies throughout the day, they lose and you lose. How? Let me list the ways:
• Decreased overall digestibility
• Increased acidosis
• Erratic feed intake
• Lower milk-fat tests
• Increased incidence of metabolic disease
Sorting can be caused by long particles, dry forages (greater than 60%), widely varying ingredient density, or too much dry hay. In each case, the physical attributes of the diet allow it to be easily separated by the cow.
Other factors may also be involved. They include:
• Feed bunk space per cow
• Amount of time that feed is available
• How many times a day that a total mixed ration is fed
• Number of times that feed is pushed up
High-producing cows, according to research, have the greatest ability to sort feed over other herd groups. Feeding high-producing cows is “riding the line” between adequate physically effective neutral detergent fiber, or peNDF, and sorting of higher NDF forages. Cows will sort out longer material if there’s too much of it.
Cows are adept sorters! They typically eat large particles last and sort against large particles, especially those with stems.
Dry alfalfa hay is easy for dairy cows to sort. But dry, coarsely chopped corn silage and long grass hay also can also be sorted.
How to reduce sorting
Feeding more frequently and pushing up feed more often will reduce sorting. So will feeding high-quality hay.
Processing dry hay and corn silage (especially if it’s dry) will reduce sorting without compromising peNDF. Double-check your chopper’s processor to make sure it’s functioning properly and that knives are sharp to avoid long pieces of cornstalks, leaves and cobs.
Feeding fibrous byproduct feeds like soy hulls, citrus pulp and beet pulp can help mitigate rumen pH by increasing diet NDF content without adding long particles. Avoid feeding diets having more than a third of the forage longer than 4 inches.
Also keep in mind that anything that increases competition at the feed bunk also increases the possibility for sorting. Grouping cows by body size will help even out competition for feed.
Carson and husband Steve partner in Harkdale Farms of Newbury, Vt. She’s also a professor at Vermont Technical College.
This article published in the October, 2010 edition of AMERICAN AGRICULTURIST.