Processing and chop length effects in brown-midrib corn silage on intake, digestion, and milk production by dairy cows.

Publisher: American Dairy Science Association Country of Publication: United States NLM ID: 2985126R Publication Model: Print Cited Medium: Print ISSN: 0022-0302 (Print) Linking ISSN: 00220302 NLM ISO Abbreviation: J Dairy Sci Subsets: MEDLINE

Publication: Champaign, IL : American Dairy Science Association
Original Publication: Lancaster, Pa. [etc.]

Digestion* ; Eating* ; Energy Intake* ; Zea mays*/chemistry; Cattle/*physiology ; Food Handling/*methods ; Milk/*metabolism; Animal Feed ; Animals ; Female ; Lactation/physiology ; Mastication/physiology ; Medicago sativa ; Milk/chemistry ; Particle Size ; Random Allocation ; Silage ; Weight Gain

In this experiment, we evaluated the influence of increasing chop length and mechanical processing of whole-plant brown-midrib corn silage on intake, digestion, and milk production by dairy cows. Corn silage treatments were harvested at three-quarter milk line stage of maturity at 13- and 19-mm theoretical chop length without processing, or at 19- and 32-mm theoretical chop length with processing at a 2-mm roll clearance. Twenty-four multiparous Holstein cows that averaged 102 +/- 17 d in milk at trial initiation were randomly assigned to treatments in a replicated 4 x 4 Latin square design with 28-d periods. Preplanned orthogonal contrasts were used to evaluate effects of processing (19 processed vs. 19 mm unprocessed) and chop length (13 vs. 19 mm unprocessed and 19 vs. 32 mm processed). Treatments were fed in total mixed rations containing 60% forage (67% corn silage and 33% alfalfa silage) and 40% shelled corn and soybean meal-based concentrate (dry matter basis). Milk yield was unaffected by treatment. Dry matter intake was unaffected by corn silage processing, but increasing corn silage chop length reduced dry matter intake in unprocessed (26.6 vs. 25.5 kg/d) and processed (25.9 vs. 25.1 kg/d) chop length contrasts. Processing reduced milk fat content (3.36 vs. 3.11%) and yield (1.43 vs. 1.35 kg/d), increased total-tract starch digestion (92.9 vs. 97.4%), and decreased total-tract neutral detergent fiber digestion (51.0 vs. 41.8%). Total chewing time (min/d) was unaffected by treatment. Masticate mean particle length was unaffected by chop length in unprocessed and processed corn silage treatments. In this study with brown-midrib corn silage fed to dairy cows producing 43 kg/d of milk, there were no benefits from crop processing or increasing chop length on lactation performance.

Date Created: 20020413 Date Completed: 20021112 Latest Revision: 20181130

20240627

10.3168/jds.S0022-0302(02)74115-5

11949866