by Amanda Smith, Associate Editor
Feed refusals and feed efficiency. They go hand in hand and have taken center stage as producers attempt to capitalize on their resources.
Targeting lower feed refusals reduces waste and provides an overall gain in efficiency on a pen basis, noted Rick Grant at the Miner Institute. In turn, this could lower the prevalence of sorting and result in cows consuming a diet closer to what was actually formulated. At the pen level, University of Guelph research suggests that, with feed refusals between 3 and 5 percent, sorting will be virtually eliminated.
Higher levels of feed refusals tend to be associated with additional sorting against long particles. Each 2 percent rise in refusals was associated with a 1 percent boost in sorting against long particles. Compounding this, higher refusal rates will reduce feed efficiency on a pen basis. Overcrowding further hinders the herd, as it expands the variation in the ration consumed among cows.
On the flip side, some herds feed to a clean bunk in an effort to minimize TMR waste. When fed for low refusals, cows typically have a greater eating rate and may be at a greater risk for acidosis. A cow's motivation to eat rises markedly after three hours without feed, and restricting feed access by 10 hours per day reduced dry matter intake by 3.5 pounds per day.
When targeting lower refusal rates (2 to 3 percent), though, you must ask yourself: Can I guarantee that feed intake will not be restricted and that feeding behavior won't be altered in my herd?
