by Amanda Smith, Hoard's Dairyman Associate Editor

Improper ration preparation and excessive sorting can defeat our goals to provide a consistent diet. These dietary deficiencies then undermine our herd goals for feed intake, milk yield and efficiency of milk production. How accurately your ration compares to its computerized counterpart and the precision with which it's blended either bolster or rob the bulk tank.

Analyzing 22 Canadian herds feeding a TMR, researchers with the University of Guelph found that:

• Every 0.5-point increase in net energy variation led to a 2.2-pound drop in daily dry matter intake, 7-pound reduction in milk yield and a 4.3 percent drop in production efficiency.
  
  
• Each 5 percent jump in long particle variability from a 19.8 percent baseline (see table) was associated with a 2.5-pound production drop and 2.6 percent reduction in milk production efficiency.
  
  
• The greatest variability from day-to-day ration mixing was the percentage of long and fine particles within the TMR.
  
  
• Even more significant than between day variations were the differences in what was delivered and had been formulated on paper.

Significant TMR variability exists on many farms. Daily composition consistency is key to improving herd-level productivity.