Dry matter intake and neutral detergent fiber intake of dairy cattle.

摘要

Accurately determining feed intake of dairy cattle is essential to formulate cost effective, nutritionally balanced diets. Understanding factors such as neutral detergent fiber (NDF) and how they affect feed intake is needed.; Alfalfa leaf meal (ALM) was included at 0, 12.5 or 25% of pelleted calf starters fed to Holstein calves from 4 to 60 days of age. Calved fed starter with 12.5 and 25% ALM had similar average daily gains and feed intake to calves fed a commercial (0% ALM) calf starter. When ALM partially replaced either by-products (30% NDF) or forages (34% NDF) in diets fed to lactating dairy cows, changes in milk production and dry matter intake (DMI) indicated ALM was not a profitable alternative to by-products or forages.; A two year study was conducted to investigate the optimum feeding level of a leafy corn silage hybrid (17, 18, 20, 22, 24, and 26% NDF from forage) in diets for lactating Holstein cows. As NDF from corn silage increased, DMI decreased and milk production increased for multiparous cows. Level of NDF from corn silage did not affect milk production or feed intake of primiparous cows.; Previously developed DMI prediction equations were evaluated for their accuracy in predicting the average pen DMI of lactating dairy cows on three commercial dairy farms. The most accurate equations were developed by the National Research Council (2001) and May (1994). Accurate determination of average milk production, days in milk, and body weight for a pen of lactating Holstein cows on a specific day is needed to attain an accurate prediction of DMI using these equations.; Equations were developed to predict the average per cow DMI per day of lactating Holstein cows grouped in freestall barns. Variables included in the equations were easily attainable from on-farm data and accounted for 77 to 82% of the variation in actual DMI. Climate accounted for more variation in DMI than previously reported in published equations while milk production and composition accounted for less.