When given the chance, heifers will sort their feed — just like lactating cows. Research published in the February 2006 issue of the Professional Animal Scientist evaluates the sorting behavior and dry matter intake of heifers exposed to five different hay-feeding strategies.

The five hay-feeding strategies included: (1) Long hay incorporated into a TMR, (2) Bale-cut hay incorporated into a TMR, (3) Chopped hay incorporated into a TMR, (4) Top-dressed long hay and (5) Top-dressed bale-cut hay. 

Here are some of the results:

  • Top-dressed long hay and top-dressed bale-cut hay reduced dry matter intake by 1.1 pounds per head per day compared to when it was incorporated into the ration.
  • Heifers “heavily refused” long particles, those greater than 12.5 millimeters, in all the diets.
  • Heifers refused 70 percent to 80 percent of corn cobs fed.

When heifers are fed more dry matter than they can consume, they will sort out feeds such as high-fiber forage particles or corn cobs. As a result, the heifers may end up consuming more energy than what the diet was formulated to contain and the chance of over-conditioning is increased, says Pat Hoffman, dairy researcher at the University of Wisconsin’s Marshfield Agricultural Research Station, where the study was done. “Bunk management is critical to assure heifers are consuming high-fiber, low-energy feeds as intended,” he says.

February 2006 Professional Animal Scientist; Pat Hoffman, Universityof Wisconsin