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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Research » Publications at this Location » Publication #94274
Title: MECHANICAL MACERATION OF FORAGES

Author
item HINTZ, RODNEY - W-L RES., EVANSVILLE, WI
item Koegel, Richard
item KRAUS, TIMOTHY - NEW HOLLAND-NA
item Mertens, David

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/20/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Forage crops constitute an important part of the rations of ruminant animals such as cattle and sheep. Value of forage crops is frequently severely diminished by rain damage which occurs during field drying of the crop. In addition, value is decreased by the fact that a certain part of the fiber fraction is not digested. Severe mechanical processing, sometimes scalled maceration, can triple the field drying rate under favorable conditions, thus greatly reducing the risk of rain damage during drydown. It has also been shown to increase fiber digestibility by rupturing plant cells, exposing more and different surface area to the digestive process. In order to verify the increased digestibility (increased energy derived) of severely processed alfalfa, a number of feeding trials were conducted using sheep, goats, or dairy cattle, respectively, to compare their performance on conventional or severely processed forage, either as hay or silage. All comparisons showed advantages of the latter in milk production and/or weight gain. The higher energy derived from severely processed forage crops makes them potentially substitutable for part of the grain used as an energy source in current rations. This would improve production economics and reduce the cost of animal products to the consumer while earning the producer a reasonable profit.

Technical Abstract: Maceration is an intensive forage conditioning process that can increase field drying rates by as much as 300%. Because maceration shreds the forage and reduces its rigidity, improvements in bulk density, silage compaction and ensiling characteristics have been observed. Macerating forage also increases the surface area available for microbial attachment in the rumen, ,thereby increasing forage digestibility and animal performance. Feeding trials with sheep have shown increases in DMI of 5 to 31% and increases in DM digestibility of from 14 to 16 percentage units. Lactation studies have demonstrated increases in milk production and bodyweight gain for lactating Holstein cows; however, there is a consistent decrease in milk fat percentage when dairy cattle are fed macerated forage. In vitro studies have shown that maceration decreases lag time associated with NDF digestion and increases rate of NDF digestion. In situ digestibility studies have shown that maceration increases the size of the instantly soluble DM pool and decreases lag time associated with NDF digestion, but may not consistently alter the rate or extent of DM and NDF digestion.