Summary and Implications
The relationships between body condition score (BCS) observed during the first 45 days of lactation and two measures of feed efficiency, residual feed intake (RFI) and gross efficiency (GE) defined as milk energy / DMI, measured during mid-lactation were assessed in 255 first lactation Holstein cows. No significant differences in BCS at calving and at approximately 40 days in milk (DIM) nor in BCS loss during the first 25 and first 45 DIM were observed between the most feed efficient and feed inefficient cows when either RFI or GE was used as the measure of feed efficiency. However when feed efficiency was measured as GE, feed efficient cows had significantly lower BCS at 40 DIM. Our findings suggest that selection based on RFI as a measure of feed efficiency during mid-lactation should not impact BCS loss during early lactation.
Iowa State University
Hardie, Lydia C. and Spurlock, Diane M.
"Relationship between Early Lactation BCS and Mid-Lactation Feed Efficiency in Dairy Cattle,"
Animal Industry Report:
AS 661, ASL R2965.
Available at: http://lib.dr.iastate.edu/ans_air/vol661/iss1/28