Abstract #T191

# T191
Forage in close-up rations: Type, inclusion rate, and dry matter adjustments.
Rúbia Lopes*1, Noelia Silva-del-Río1, 1Veterinary Medicine Teaching and Research Center, University of California-Davis, Tulare, CA.

The objective of the present study was to describe the type, inclusion rate (DM %), and frequency of DM adjustments of forages incorporated into the close-up recipe (CUR). Records from a 12-mo (n = 23) or 5-mo (n = 1) consecutive period were extracted from a herd feeding management software (FeedWatch 7.0). Enrolled dairies were located in California and ranged in size from 1,100 to 6,900 cows. The data set included the following variables: date, recipe type, recipe number, ingredient type, ingredient quantity, and ingredient DM. Descriptive statistics were conducted with MedCalc (v. 18.) The median number of forages included in CUR ranged from 2 to 4 across dairies. Corn silage was used in 95% of dairies and alfalfa forages in 83% of dairies [hay (low K: 60%, unknown: 23%), haylage (8%), green chop (4%)]. Half of the dairies incorporated a combination of corn silage and alfalfa hay as the sole sources of forage in CUR. Other forages included in CUR were oat hay (25%), wheat straw hay (25%), wheat silage (12%), and sorghum silage (8%). Across dairies, forage inclusion in CUR ranged from 45 to 90%, with most dairies (70%) including at least 65% of forage. Within dairy, forage inclusion varied over time; it increased up to 2 to 38% from Q10 to Q90. Corn silage inclusion in CUR was <40% (8%), 40 to 60% (56%), and >60% (34%). Within dairy, corn silage inclusion varied, increasing 4 to 77% from Q10 to Q90. Alfalfa hay inclusion in CUR averaged <30% (20%), 30 to 40% (30%), 40 to 50% (40%) and > 50% (10%). On dairies with 12-mo data set (n = 23), DM adjustments for corn silage were performed 0 (17.3%), 3 to < 6 (26.0%), 6 to < 12 (30.4%) or ≥12 (26.0%) times per year. For corn silage, adjustments in DM represented a change of 1.5 to 10% in percentage units of DM. DM adjustments for alfalfa hay were observed 0 (85%) or 1 (15%) time per year; the changes made were of 0.3 to 3 percentage units. Overall, in our study forage inclusion rate varied within and across dairies. Alfalfa forages were used on most dairies but only 60% recorded alfalfa as low K. There seems to be an opportunity to increase the frequency of DM adjustments for corn silage on dairies.

Key Words: forage, DM analysis, dairy cow